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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 
31 /*
32  * Btree magic numbers.
33  */
34 static const uint32_t xfs_magics[2][XFS_BTNUM_MAX] = {
35 	{ XFS_ABTB_MAGIC, XFS_ABTC_MAGIC, 0, XFS_BMAP_MAGIC, XFS_IBT_MAGIC,
36 	  XFS_FIBT_MAGIC, 0 },
37 	{ XFS_ABTB_CRC_MAGIC, XFS_ABTC_CRC_MAGIC, XFS_RMAP_CRC_MAGIC,
38 	  XFS_BMAP_CRC_MAGIC, XFS_IBT_CRC_MAGIC, XFS_FIBT_CRC_MAGIC,
39 	  XFS_REFC_CRC_MAGIC }
40 };
41 
42 uint32_t
xfs_btree_magic(int crc,xfs_btnum_t btnum)43 xfs_btree_magic(
44 	int			crc,
45 	xfs_btnum_t		btnum)
46 {
47 	uint32_t		magic = xfs_magics[crc][btnum];
48 
49 	/* Ensure we asked for crc for crc-only magics. */
50 	ASSERT(magic != 0);
51 	return magic;
52 }
53 
54 /*
55  * These sibling pointer checks are optimised for null sibling pointers. This
56  * happens a lot, and we don't need to byte swap at runtime if the sibling
57  * pointer is NULL.
58  *
59  * These are explicitly marked at inline because the cost of calling them as
60  * functions instead of inlining them is about 36 bytes extra code per call site
61  * on x86-64. Yes, gcc-11 fails to inline them, and explicit inlining of these
62  * two sibling check functions reduces the compiled code size by over 300
63  * bytes.
64  */
65 static inline xfs_failaddr_t
xfs_btree_check_lblock_siblings(struct xfs_mount * mp,struct xfs_btree_cur * cur,int level,xfs_fsblock_t fsb,__be64 dsibling)66 xfs_btree_check_lblock_siblings(
67 	struct xfs_mount	*mp,
68 	struct xfs_btree_cur	*cur,
69 	int			level,
70 	xfs_fsblock_t		fsb,
71 	__be64			dsibling)
72 {
73 	xfs_fsblock_t		sibling;
74 
75 	if (dsibling == cpu_to_be64(NULLFSBLOCK))
76 		return NULL;
77 
78 	sibling = be64_to_cpu(dsibling);
79 	if (sibling == fsb)
80 		return __this_address;
81 	if (level >= 0) {
82 		if (!xfs_btree_check_lptr(cur, sibling, level + 1))
83 			return __this_address;
84 	} else {
85 		if (!xfs_verify_fsbno(mp, sibling))
86 			return __this_address;
87 	}
88 
89 	return NULL;
90 }
91 
92 static inline xfs_failaddr_t
xfs_btree_check_sblock_siblings(struct xfs_perag * pag,struct xfs_btree_cur * cur,int level,xfs_agblock_t agbno,__be32 dsibling)93 xfs_btree_check_sblock_siblings(
94 	struct xfs_perag	*pag,
95 	struct xfs_btree_cur	*cur,
96 	int			level,
97 	xfs_agblock_t		agbno,
98 	__be32			dsibling)
99 {
100 	xfs_agblock_t		sibling;
101 
102 	if (dsibling == cpu_to_be32(NULLAGBLOCK))
103 		return NULL;
104 
105 	sibling = be32_to_cpu(dsibling);
106 	if (sibling == agbno)
107 		return __this_address;
108 	if (level >= 0) {
109 		if (!xfs_btree_check_sptr(cur, sibling, level + 1))
110 			return __this_address;
111 	} else {
112 		if (!xfs_verify_agbno(pag, sibling))
113 			return __this_address;
114 	}
115 	return NULL;
116 }
117 
118 /*
119  * Check a long btree block header.  Return the address of the failing check,
120  * or NULL if everything is ok.
121  */
122 xfs_failaddr_t
__xfs_btree_check_lblock(struct xfs_btree_cur * cur,struct xfs_btree_block * block,int level,struct xfs_buf * bp)123 __xfs_btree_check_lblock(
124 	struct xfs_btree_cur	*cur,
125 	struct xfs_btree_block	*block,
126 	int			level,
127 	struct xfs_buf		*bp)
128 {
129 	struct xfs_mount	*mp = cur->bc_mp;
130 	xfs_btnum_t		btnum = cur->bc_btnum;
131 	int			crc = xfs_has_crc(mp);
132 	xfs_failaddr_t		fa;
133 	xfs_fsblock_t		fsb = NULLFSBLOCK;
134 
135 	if (crc) {
136 		if (!uuid_equal(&block->bb_u.l.bb_uuid, &mp->m_sb.sb_meta_uuid))
137 			return __this_address;
138 		if (block->bb_u.l.bb_blkno !=
139 		    cpu_to_be64(bp ? xfs_buf_daddr(bp) : XFS_BUF_DADDR_NULL))
140 			return __this_address;
141 		if (block->bb_u.l.bb_pad != cpu_to_be32(0))
142 			return __this_address;
143 	}
144 
145 	if (be32_to_cpu(block->bb_magic) != xfs_btree_magic(crc, btnum))
146 		return __this_address;
147 	if (be16_to_cpu(block->bb_level) != level)
148 		return __this_address;
149 	if (be16_to_cpu(block->bb_numrecs) >
150 	    cur->bc_ops->get_maxrecs(cur, level))
151 		return __this_address;
152 
153 	if (bp)
154 		fsb = XFS_DADDR_TO_FSB(mp, xfs_buf_daddr(bp));
155 
156 	fa = xfs_btree_check_lblock_siblings(mp, cur, level, fsb,
157 			block->bb_u.l.bb_leftsib);
158 	if (!fa)
159 		fa = xfs_btree_check_lblock_siblings(mp, cur, level, fsb,
160 				block->bb_u.l.bb_rightsib);
161 	return fa;
162 }
163 
164 /* Check a long btree block header. */
165 static int
xfs_btree_check_lblock(struct xfs_btree_cur * cur,struct xfs_btree_block * block,int level,struct xfs_buf * bp)166 xfs_btree_check_lblock(
167 	struct xfs_btree_cur	*cur,
168 	struct xfs_btree_block	*block,
169 	int			level,
170 	struct xfs_buf		*bp)
171 {
172 	struct xfs_mount	*mp = cur->bc_mp;
173 	xfs_failaddr_t		fa;
174 
175 	fa = __xfs_btree_check_lblock(cur, block, level, bp);
176 	if (XFS_IS_CORRUPT(mp, fa != NULL) ||
177 	    XFS_TEST_ERROR(false, mp, XFS_ERRTAG_BTREE_CHECK_LBLOCK)) {
178 		if (bp)
179 			trace_xfs_btree_corrupt(bp, _RET_IP_);
180 		return -EFSCORRUPTED;
181 	}
182 	return 0;
183 }
184 
185 /*
186  * Check a short btree block header.  Return the address of the failing check,
187  * or NULL if everything is ok.
188  */
189 xfs_failaddr_t
__xfs_btree_check_sblock(struct xfs_btree_cur * cur,struct xfs_btree_block * block,int level,struct xfs_buf * bp)190 __xfs_btree_check_sblock(
191 	struct xfs_btree_cur	*cur,
192 	struct xfs_btree_block	*block,
193 	int			level,
194 	struct xfs_buf		*bp)
195 {
196 	struct xfs_mount	*mp = cur->bc_mp;
197 	struct xfs_perag	*pag = cur->bc_ag.pag;
198 	xfs_btnum_t		btnum = cur->bc_btnum;
199 	int			crc = xfs_has_crc(mp);
200 	xfs_failaddr_t		fa;
201 	xfs_agblock_t		agbno = NULLAGBLOCK;
202 
203 	if (crc) {
204 		if (!uuid_equal(&block->bb_u.s.bb_uuid, &mp->m_sb.sb_meta_uuid))
205 			return __this_address;
206 		if (block->bb_u.s.bb_blkno !=
207 		    cpu_to_be64(bp ? xfs_buf_daddr(bp) : XFS_BUF_DADDR_NULL))
208 			return __this_address;
209 	}
210 
211 	if (be32_to_cpu(block->bb_magic) != xfs_btree_magic(crc, btnum))
212 		return __this_address;
213 	if (be16_to_cpu(block->bb_level) != level)
214 		return __this_address;
215 	if (be16_to_cpu(block->bb_numrecs) >
216 	    cur->bc_ops->get_maxrecs(cur, level))
217 		return __this_address;
218 
219 	if (bp)
220 		agbno = xfs_daddr_to_agbno(mp, xfs_buf_daddr(bp));
221 
222 	fa = xfs_btree_check_sblock_siblings(pag, cur, level, agbno,
223 			block->bb_u.s.bb_leftsib);
224 	if (!fa)
225 		fa = xfs_btree_check_sblock_siblings(pag, cur, level, agbno,
226 				block->bb_u.s.bb_rightsib);
227 	return fa;
228 }
229 
230 /* Check a short btree block header. */
231 STATIC int
xfs_btree_check_sblock(struct xfs_btree_cur * cur,struct xfs_btree_block * block,int level,struct xfs_buf * bp)232 xfs_btree_check_sblock(
233 	struct xfs_btree_cur	*cur,
234 	struct xfs_btree_block	*block,
235 	int			level,
236 	struct xfs_buf		*bp)
237 {
238 	struct xfs_mount	*mp = cur->bc_mp;
239 	xfs_failaddr_t		fa;
240 
241 	fa = __xfs_btree_check_sblock(cur, block, level, bp);
242 	if (XFS_IS_CORRUPT(mp, fa != NULL) ||
243 	    XFS_TEST_ERROR(false, mp, XFS_ERRTAG_BTREE_CHECK_SBLOCK)) {
244 		if (bp)
245 			trace_xfs_btree_corrupt(bp, _RET_IP_);
246 		return -EFSCORRUPTED;
247 	}
248 	return 0;
249 }
250 
251 /*
252  * Debug routine: check that block header is ok.
253  */
254 int
xfs_btree_check_block(struct xfs_btree_cur * cur,struct xfs_btree_block * block,int level,struct xfs_buf * bp)255 xfs_btree_check_block(
256 	struct xfs_btree_cur	*cur,	/* btree cursor */
257 	struct xfs_btree_block	*block,	/* generic btree block pointer */
258 	int			level,	/* level of the btree block */
259 	struct xfs_buf		*bp)	/* buffer containing block, if any */
260 {
261 	if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
262 		return xfs_btree_check_lblock(cur, block, level, bp);
263 	else
264 		return xfs_btree_check_sblock(cur, block, level, bp);
265 }
266 
267 /* Check that this long pointer is valid and points within the fs. */
268 bool
xfs_btree_check_lptr(struct xfs_btree_cur * cur,xfs_fsblock_t fsbno,int level)269 xfs_btree_check_lptr(
270 	struct xfs_btree_cur	*cur,
271 	xfs_fsblock_t		fsbno,
272 	int			level)
273 {
274 	if (level <= 0)
275 		return false;
276 	return xfs_verify_fsbno(cur->bc_mp, fsbno);
277 }
278 
279 /* Check that this short pointer is valid and points within the AG. */
280 bool
xfs_btree_check_sptr(struct xfs_btree_cur * cur,xfs_agblock_t agbno,int level)281 xfs_btree_check_sptr(
282 	struct xfs_btree_cur	*cur,
283 	xfs_agblock_t		agbno,
284 	int			level)
285 {
286 	if (level <= 0)
287 		return false;
288 	return xfs_verify_agbno(cur->bc_ag.pag, agbno);
289 }
290 
291 /*
292  * Check that a given (indexed) btree pointer at a certain level of a
293  * btree is valid and doesn't point past where it should.
294  */
295 static int
xfs_btree_check_ptr(struct xfs_btree_cur * cur,const union xfs_btree_ptr * ptr,int index,int level)296 xfs_btree_check_ptr(
297 	struct xfs_btree_cur		*cur,
298 	const union xfs_btree_ptr	*ptr,
299 	int				index,
300 	int				level)
301 {
302 	if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
303 		if (xfs_btree_check_lptr(cur, be64_to_cpu((&ptr->l)[index]),
304 				level))
305 			return 0;
306 		xfs_err(cur->bc_mp,
307 "Inode %llu fork %d: Corrupt btree %d pointer at level %d index %d.",
308 				cur->bc_ino.ip->i_ino,
309 				cur->bc_ino.whichfork, cur->bc_btnum,
310 				level, index);
311 	} else {
312 		if (xfs_btree_check_sptr(cur, be32_to_cpu((&ptr->s)[index]),
313 				level))
314 			return 0;
315 		xfs_err(cur->bc_mp,
316 "AG %u: Corrupt btree %d pointer at level %d index %d.",
317 				cur->bc_ag.pag->pag_agno, cur->bc_btnum,
318 				level, index);
319 	}
320 
321 	return -EFSCORRUPTED;
322 }
323 
324 #ifdef DEBUG
325 # define xfs_btree_debug_check_ptr	xfs_btree_check_ptr
326 #else
327 # define xfs_btree_debug_check_ptr(...)	(0)
328 #endif
329 
330 /*
331  * Calculate CRC on the whole btree block and stuff it into the
332  * long-form btree header.
333  *
334  * Prior to calculting the CRC, pull the LSN out of the buffer log item and put
335  * it into the buffer so recovery knows what the last modification was that made
336  * it to disk.
337  */
338 void
xfs_btree_lblock_calc_crc(struct xfs_buf * bp)339 xfs_btree_lblock_calc_crc(
340 	struct xfs_buf		*bp)
341 {
342 	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
343 	struct xfs_buf_log_item	*bip = bp->b_log_item;
344 
345 	if (!xfs_has_crc(bp->b_mount))
346 		return;
347 	if (bip)
348 		block->bb_u.l.bb_lsn = cpu_to_be64(bip->bli_item.li_lsn);
349 	xfs_buf_update_cksum(bp, XFS_BTREE_LBLOCK_CRC_OFF);
350 }
351 
352 bool
xfs_btree_lblock_verify_crc(struct xfs_buf * bp)353 xfs_btree_lblock_verify_crc(
354 	struct xfs_buf		*bp)
355 {
356 	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
357 	struct xfs_mount	*mp = bp->b_mount;
358 
359 	if (xfs_has_crc(mp)) {
360 		if (!xfs_log_check_lsn(mp, be64_to_cpu(block->bb_u.l.bb_lsn)))
361 			return false;
362 		return xfs_buf_verify_cksum(bp, XFS_BTREE_LBLOCK_CRC_OFF);
363 	}
364 
365 	return true;
366 }
367 
368 /*
369  * Calculate CRC on the whole btree block and stuff it into the
370  * short-form btree header.
371  *
372  * Prior to calculting the CRC, pull the LSN out of the buffer log item and put
373  * it into the buffer so recovery knows what the last modification was that made
374  * it to disk.
375  */
376 void
xfs_btree_sblock_calc_crc(struct xfs_buf * bp)377 xfs_btree_sblock_calc_crc(
378 	struct xfs_buf		*bp)
379 {
380 	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
381 	struct xfs_buf_log_item	*bip = bp->b_log_item;
382 
383 	if (!xfs_has_crc(bp->b_mount))
384 		return;
385 	if (bip)
386 		block->bb_u.s.bb_lsn = cpu_to_be64(bip->bli_item.li_lsn);
387 	xfs_buf_update_cksum(bp, XFS_BTREE_SBLOCK_CRC_OFF);
388 }
389 
390 bool
xfs_btree_sblock_verify_crc(struct xfs_buf * bp)391 xfs_btree_sblock_verify_crc(
392 	struct xfs_buf		*bp)
393 {
394 	struct xfs_btree_block  *block = XFS_BUF_TO_BLOCK(bp);
395 	struct xfs_mount	*mp = bp->b_mount;
396 
397 	if (xfs_has_crc(mp)) {
398 		if (!xfs_log_check_lsn(mp, be64_to_cpu(block->bb_u.s.bb_lsn)))
399 			return false;
400 		return xfs_buf_verify_cksum(bp, XFS_BTREE_SBLOCK_CRC_OFF);
401 	}
402 
403 	return true;
404 }
405 
406 static int
xfs_btree_free_block(struct xfs_btree_cur * cur,struct xfs_buf * bp)407 xfs_btree_free_block(
408 	struct xfs_btree_cur	*cur,
409 	struct xfs_buf		*bp)
410 {
411 	int			error;
412 
413 	error = cur->bc_ops->free_block(cur, bp);
414 	if (!error) {
415 		xfs_trans_binval(cur->bc_tp, bp);
416 		XFS_BTREE_STATS_INC(cur, free);
417 	}
418 	return error;
419 }
420 
421 /*
422  * Delete the btree cursor.
423  */
424 void
xfs_btree_del_cursor(struct xfs_btree_cur * cur,int error)425 xfs_btree_del_cursor(
426 	struct xfs_btree_cur	*cur,		/* btree cursor */
427 	int			error)		/* del because of error */
428 {
429 	int			i;		/* btree level */
430 
431 	/*
432 	 * Clear the buffer pointers and release the buffers. If we're doing
433 	 * this because of an error, inspect all of the entries in the bc_bufs
434 	 * array for buffers to be unlocked. This is because some of the btree
435 	 * code works from level n down to 0, and if we get an error along the
436 	 * way we won't have initialized all the entries down to 0.
437 	 */
438 	for (i = 0; i < cur->bc_nlevels; i++) {
439 		if (cur->bc_levels[i].bp)
440 			xfs_trans_brelse(cur->bc_tp, cur->bc_levels[i].bp);
441 		else if (!error)
442 			break;
443 	}
444 
445 	/*
446 	 * If we are doing a BMBT update, the number of unaccounted blocks
447 	 * allocated during this cursor life time should be zero. If it's not
448 	 * zero, then we should be shut down or on our way to shutdown due to
449 	 * cancelling a dirty transaction on error.
450 	 */
451 	ASSERT(cur->bc_btnum != XFS_BTNUM_BMAP || cur->bc_ino.allocated == 0 ||
452 	       xfs_is_shutdown(cur->bc_mp) || error != 0);
453 	if (unlikely(cur->bc_flags & XFS_BTREE_STAGING))
454 		kmem_free(cur->bc_ops);
455 	if (!(cur->bc_flags & XFS_BTREE_LONG_PTRS) && cur->bc_ag.pag)
456 		xfs_perag_put(cur->bc_ag.pag);
457 	kmem_cache_free(cur->bc_cache, cur);
458 }
459 
460 /*
461  * Duplicate the btree cursor.
462  * Allocate a new one, copy the record, re-get the buffers.
463  */
464 int					/* error */
xfs_btree_dup_cursor(struct xfs_btree_cur * cur,struct xfs_btree_cur ** ncur)465 xfs_btree_dup_cursor(
466 	struct xfs_btree_cur *cur,		/* input cursor */
467 	struct xfs_btree_cur **ncur)		/* output cursor */
468 {
469 	struct xfs_buf	*bp;		/* btree block's buffer pointer */
470 	int		error;		/* error return value */
471 	int		i;		/* level number of btree block */
472 	xfs_mount_t	*mp;		/* mount structure for filesystem */
473 	struct xfs_btree_cur *new;		/* new cursor value */
474 	xfs_trans_t	*tp;		/* transaction pointer, can be NULL */
475 
476 	tp = cur->bc_tp;
477 	mp = cur->bc_mp;
478 
479 	/*
480 	 * Allocate a new cursor like the old one.
481 	 */
482 	new = cur->bc_ops->dup_cursor(cur);
483 
484 	/*
485 	 * Copy the record currently in the cursor.
486 	 */
487 	new->bc_rec = cur->bc_rec;
488 
489 	/*
490 	 * For each level current, re-get the buffer and copy the ptr value.
491 	 */
492 	for (i = 0; i < new->bc_nlevels; i++) {
493 		new->bc_levels[i].ptr = cur->bc_levels[i].ptr;
494 		new->bc_levels[i].ra = cur->bc_levels[i].ra;
495 		bp = cur->bc_levels[i].bp;
496 		if (bp) {
497 			error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp,
498 						   xfs_buf_daddr(bp), mp->m_bsize,
499 						   0, &bp,
500 						   cur->bc_ops->buf_ops);
501 			if (error) {
502 				xfs_btree_del_cursor(new, error);
503 				*ncur = NULL;
504 				return error;
505 			}
506 		}
507 		new->bc_levels[i].bp = bp;
508 	}
509 	*ncur = new;
510 	return 0;
511 }
512 
513 /*
514  * XFS btree block layout and addressing:
515  *
516  * There are two types of blocks in the btree: leaf and non-leaf blocks.
517  *
518  * The leaf record start with a header then followed by records containing
519  * the values.  A non-leaf block also starts with the same header, and
520  * then first contains lookup keys followed by an equal number of pointers
521  * to the btree blocks at the previous level.
522  *
523  *		+--------+-------+-------+-------+-------+-------+-------+
524  * Leaf:	| header | rec 1 | rec 2 | rec 3 | rec 4 | rec 5 | rec N |
525  *		+--------+-------+-------+-------+-------+-------+-------+
526  *
527  *		+--------+-------+-------+-------+-------+-------+-------+
528  * Non-Leaf:	| header | key 1 | key 2 | key N | ptr 1 | ptr 2 | ptr N |
529  *		+--------+-------+-------+-------+-------+-------+-------+
530  *
531  * The header is called struct xfs_btree_block for reasons better left unknown
532  * and comes in different versions for short (32bit) and long (64bit) block
533  * pointers.  The record and key structures are defined by the btree instances
534  * and opaque to the btree core.  The block pointers are simple disk endian
535  * integers, available in a short (32bit) and long (64bit) variant.
536  *
537  * The helpers below calculate the offset of a given record, key or pointer
538  * into a btree block (xfs_btree_*_offset) or return a pointer to the given
539  * record, key or pointer (xfs_btree_*_addr).  Note that all addressing
540  * inside the btree block is done using indices starting at one, not zero!
541  *
542  * If XFS_BTREE_OVERLAPPING is set, then this btree supports keys containing
543  * overlapping intervals.  In such a tree, records are still sorted lowest to
544  * highest and indexed by the smallest key value that refers to the record.
545  * However, nodes are different: each pointer has two associated keys -- one
546  * indexing the lowest key available in the block(s) below (the same behavior
547  * as the key in a regular btree) and another indexing the highest key
548  * available in the block(s) below.  Because records are /not/ sorted by the
549  * highest key, all leaf block updates require us to compute the highest key
550  * that matches any record in the leaf and to recursively update the high keys
551  * in the nodes going further up in the tree, if necessary.  Nodes look like
552  * this:
553  *
554  *		+--------+-----+-----+-----+-----+-----+-------+-------+-----+
555  * Non-Leaf:	| header | lo1 | hi1 | lo2 | hi2 | ... | ptr 1 | ptr 2 | ... |
556  *		+--------+-----+-----+-----+-----+-----+-------+-------+-----+
557  *
558  * To perform an interval query on an overlapped tree, perform the usual
559  * depth-first search and use the low and high keys to decide if we can skip
560  * that particular node.  If a leaf node is reached, return the records that
561  * intersect the interval.  Note that an interval query may return numerous
562  * entries.  For a non-overlapped tree, simply search for the record associated
563  * with the lowest key and iterate forward until a non-matching record is
564  * found.  Section 14.3 ("Interval Trees") of _Introduction to Algorithms_ by
565  * Cormen, Leiserson, Rivest, and Stein (2nd or 3rd ed. only) discuss this in
566  * more detail.
567  *
568  * Why do we care about overlapping intervals?  Let's say you have a bunch of
569  * reverse mapping records on a reflink filesystem:
570  *
571  * 1: +- file A startblock B offset C length D -----------+
572  * 2:      +- file E startblock F offset G length H --------------+
573  * 3:      +- file I startblock F offset J length K --+
574  * 4:                                                        +- file L... --+
575  *
576  * Now say we want to map block (B+D) into file A at offset (C+D).  Ideally,
577  * we'd simply increment the length of record 1.  But how do we find the record
578  * that ends at (B+D-1) (i.e. record 1)?  A LE lookup of (B+D-1) would return
579  * record 3 because the keys are ordered first by startblock.  An interval
580  * query would return records 1 and 2 because they both overlap (B+D-1), and
581  * from that we can pick out record 1 as the appropriate left neighbor.
582  *
583  * In the non-overlapped case you can do a LE lookup and decrement the cursor
584  * because a record's interval must end before the next record.
585  */
586 
587 /*
588  * Return size of the btree block header for this btree instance.
589  */
xfs_btree_block_len(struct xfs_btree_cur * cur)590 static inline size_t xfs_btree_block_len(struct xfs_btree_cur *cur)
591 {
592 	if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
593 		if (cur->bc_flags & XFS_BTREE_CRC_BLOCKS)
594 			return XFS_BTREE_LBLOCK_CRC_LEN;
595 		return XFS_BTREE_LBLOCK_LEN;
596 	}
597 	if (cur->bc_flags & XFS_BTREE_CRC_BLOCKS)
598 		return XFS_BTREE_SBLOCK_CRC_LEN;
599 	return XFS_BTREE_SBLOCK_LEN;
600 }
601 
602 /*
603  * Return size of btree block pointers for this btree instance.
604  */
xfs_btree_ptr_len(struct xfs_btree_cur * cur)605 static inline size_t xfs_btree_ptr_len(struct xfs_btree_cur *cur)
606 {
607 	return (cur->bc_flags & XFS_BTREE_LONG_PTRS) ?
608 		sizeof(__be64) : sizeof(__be32);
609 }
610 
611 /*
612  * Calculate offset of the n-th record in a btree block.
613  */
614 STATIC size_t
xfs_btree_rec_offset(struct xfs_btree_cur * cur,int n)615 xfs_btree_rec_offset(
616 	struct xfs_btree_cur	*cur,
617 	int			n)
618 {
619 	return xfs_btree_block_len(cur) +
620 		(n - 1) * cur->bc_ops->rec_len;
621 }
622 
623 /*
624  * Calculate offset of the n-th key in a btree block.
625  */
626 STATIC size_t
xfs_btree_key_offset(struct xfs_btree_cur * cur,int n)627 xfs_btree_key_offset(
628 	struct xfs_btree_cur	*cur,
629 	int			n)
630 {
631 	return xfs_btree_block_len(cur) +
632 		(n - 1) * cur->bc_ops->key_len;
633 }
634 
635 /*
636  * Calculate offset of the n-th high key in a btree block.
637  */
638 STATIC size_t
xfs_btree_high_key_offset(struct xfs_btree_cur * cur,int n)639 xfs_btree_high_key_offset(
640 	struct xfs_btree_cur	*cur,
641 	int			n)
642 {
643 	return xfs_btree_block_len(cur) +
644 		(n - 1) * cur->bc_ops->key_len + (cur->bc_ops->key_len / 2);
645 }
646 
647 /*
648  * Calculate offset of the n-th block pointer in a btree block.
649  */
650 STATIC size_t
xfs_btree_ptr_offset(struct xfs_btree_cur * cur,int n,int level)651 xfs_btree_ptr_offset(
652 	struct xfs_btree_cur	*cur,
653 	int			n,
654 	int			level)
655 {
656 	return xfs_btree_block_len(cur) +
657 		cur->bc_ops->get_maxrecs(cur, level) * cur->bc_ops->key_len +
658 		(n - 1) * xfs_btree_ptr_len(cur);
659 }
660 
661 /*
662  * Return a pointer to the n-th record in the btree block.
663  */
664 union xfs_btree_rec *
xfs_btree_rec_addr(struct xfs_btree_cur * cur,int n,struct xfs_btree_block * block)665 xfs_btree_rec_addr(
666 	struct xfs_btree_cur	*cur,
667 	int			n,
668 	struct xfs_btree_block	*block)
669 {
670 	return (union xfs_btree_rec *)
671 		((char *)block + xfs_btree_rec_offset(cur, n));
672 }
673 
674 /*
675  * Return a pointer to the n-th key in the btree block.
676  */
677 union xfs_btree_key *
xfs_btree_key_addr(struct xfs_btree_cur * cur,int n,struct xfs_btree_block * block)678 xfs_btree_key_addr(
679 	struct xfs_btree_cur	*cur,
680 	int			n,
681 	struct xfs_btree_block	*block)
682 {
683 	return (union xfs_btree_key *)
684 		((char *)block + xfs_btree_key_offset(cur, n));
685 }
686 
687 /*
688  * Return a pointer to the n-th high key in the btree block.
689  */
690 union xfs_btree_key *
xfs_btree_high_key_addr(struct xfs_btree_cur * cur,int n,struct xfs_btree_block * block)691 xfs_btree_high_key_addr(
692 	struct xfs_btree_cur	*cur,
693 	int			n,
694 	struct xfs_btree_block	*block)
695 {
696 	return (union xfs_btree_key *)
697 		((char *)block + xfs_btree_high_key_offset(cur, n));
698 }
699 
700 /*
701  * Return a pointer to the n-th block pointer in the btree block.
702  */
703 union xfs_btree_ptr *
xfs_btree_ptr_addr(struct xfs_btree_cur * cur,int n,struct xfs_btree_block * block)704 xfs_btree_ptr_addr(
705 	struct xfs_btree_cur	*cur,
706 	int			n,
707 	struct xfs_btree_block	*block)
708 {
709 	int			level = xfs_btree_get_level(block);
710 
711 	ASSERT(block->bb_level != 0);
712 
713 	return (union xfs_btree_ptr *)
714 		((char *)block + xfs_btree_ptr_offset(cur, n, level));
715 }
716 
717 struct xfs_ifork *
xfs_btree_ifork_ptr(struct xfs_btree_cur * cur)718 xfs_btree_ifork_ptr(
719 	struct xfs_btree_cur	*cur)
720 {
721 	ASSERT(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE);
722 
723 	if (cur->bc_flags & XFS_BTREE_STAGING)
724 		return cur->bc_ino.ifake->if_fork;
725 	return xfs_ifork_ptr(cur->bc_ino.ip, cur->bc_ino.whichfork);
726 }
727 
728 /*
729  * Get the root block which is stored in the inode.
730  *
731  * For now this btree implementation assumes the btree root is always
732  * stored in the if_broot field of an inode fork.
733  */
734 STATIC struct xfs_btree_block *
xfs_btree_get_iroot(struct xfs_btree_cur * cur)735 xfs_btree_get_iroot(
736 	struct xfs_btree_cur	*cur)
737 {
738 	struct xfs_ifork	*ifp = xfs_btree_ifork_ptr(cur);
739 
740 	return (struct xfs_btree_block *)ifp->if_broot;
741 }
742 
743 /*
744  * Retrieve the block pointer from the cursor at the given level.
745  * This may be an inode btree root or from a buffer.
746  */
747 struct xfs_btree_block *		/* generic btree block pointer */
xfs_btree_get_block(struct xfs_btree_cur * cur,int level,struct xfs_buf ** bpp)748 xfs_btree_get_block(
749 	struct xfs_btree_cur	*cur,	/* btree cursor */
750 	int			level,	/* level in btree */
751 	struct xfs_buf		**bpp)	/* buffer containing the block */
752 {
753 	if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
754 	    (level == cur->bc_nlevels - 1)) {
755 		*bpp = NULL;
756 		return xfs_btree_get_iroot(cur);
757 	}
758 
759 	*bpp = cur->bc_levels[level].bp;
760 	return XFS_BUF_TO_BLOCK(*bpp);
761 }
762 
763 /*
764  * Change the cursor to point to the first record at the given level.
765  * Other levels are unaffected.
766  */
767 STATIC int				/* success=1, failure=0 */
xfs_btree_firstrec(struct xfs_btree_cur * cur,int level)768 xfs_btree_firstrec(
769 	struct xfs_btree_cur	*cur,	/* btree cursor */
770 	int			level)	/* level to change */
771 {
772 	struct xfs_btree_block	*block;	/* generic btree block pointer */
773 	struct xfs_buf		*bp;	/* buffer containing block */
774 
775 	/*
776 	 * Get the block pointer for this level.
777 	 */
778 	block = xfs_btree_get_block(cur, level, &bp);
779 	if (xfs_btree_check_block(cur, block, level, bp))
780 		return 0;
781 	/*
782 	 * It's empty, there is no such record.
783 	 */
784 	if (!block->bb_numrecs)
785 		return 0;
786 	/*
787 	 * Set the ptr value to 1, that's the first record/key.
788 	 */
789 	cur->bc_levels[level].ptr = 1;
790 	return 1;
791 }
792 
793 /*
794  * Change the cursor to point to the last record in the current block
795  * at the given level.  Other levels are unaffected.
796  */
797 STATIC int				/* success=1, failure=0 */
xfs_btree_lastrec(struct xfs_btree_cur * cur,int level)798 xfs_btree_lastrec(
799 	struct xfs_btree_cur	*cur,	/* btree cursor */
800 	int			level)	/* level to change */
801 {
802 	struct xfs_btree_block	*block;	/* generic btree block pointer */
803 	struct xfs_buf		*bp;	/* buffer containing block */
804 
805 	/*
806 	 * Get the block pointer for this level.
807 	 */
808 	block = xfs_btree_get_block(cur, level, &bp);
809 	if (xfs_btree_check_block(cur, block, level, bp))
810 		return 0;
811 	/*
812 	 * It's empty, there is no such record.
813 	 */
814 	if (!block->bb_numrecs)
815 		return 0;
816 	/*
817 	 * Set the ptr value to numrecs, that's the last record/key.
818 	 */
819 	cur->bc_levels[level].ptr = be16_to_cpu(block->bb_numrecs);
820 	return 1;
821 }
822 
823 /*
824  * Compute first and last byte offsets for the fields given.
825  * Interprets the offsets table, which contains struct field offsets.
826  */
827 void
xfs_btree_offsets(uint32_t fields,const short * offsets,int nbits,int * first,int * last)828 xfs_btree_offsets(
829 	uint32_t	fields,		/* bitmask of fields */
830 	const short	*offsets,	/* table of field offsets */
831 	int		nbits,		/* number of bits to inspect */
832 	int		*first,		/* output: first byte offset */
833 	int		*last)		/* output: last byte offset */
834 {
835 	int		i;		/* current bit number */
836 	uint32_t	imask;		/* mask for current bit number */
837 
838 	ASSERT(fields != 0);
839 	/*
840 	 * Find the lowest bit, so the first byte offset.
841 	 */
842 	for (i = 0, imask = 1u; ; i++, imask <<= 1) {
843 		if (imask & fields) {
844 			*first = offsets[i];
845 			break;
846 		}
847 	}
848 	/*
849 	 * Find the highest bit, so the last byte offset.
850 	 */
851 	for (i = nbits - 1, imask = 1u << i; ; i--, imask >>= 1) {
852 		if (imask & fields) {
853 			*last = offsets[i + 1] - 1;
854 			break;
855 		}
856 	}
857 }
858 
859 /*
860  * Get a buffer for the block, return it read in.
861  * Long-form addressing.
862  */
863 int
xfs_btree_read_bufl(struct xfs_mount * mp,struct xfs_trans * tp,xfs_fsblock_t fsbno,struct xfs_buf ** bpp,int refval,const struct xfs_buf_ops * ops)864 xfs_btree_read_bufl(
865 	struct xfs_mount	*mp,		/* file system mount point */
866 	struct xfs_trans	*tp,		/* transaction pointer */
867 	xfs_fsblock_t		fsbno,		/* file system block number */
868 	struct xfs_buf		**bpp,		/* buffer for fsbno */
869 	int			refval,		/* ref count value for buffer */
870 	const struct xfs_buf_ops *ops)
871 {
872 	struct xfs_buf		*bp;		/* return value */
873 	xfs_daddr_t		d;		/* real disk block address */
874 	int			error;
875 
876 	if (!xfs_verify_fsbno(mp, fsbno))
877 		return -EFSCORRUPTED;
878 	d = XFS_FSB_TO_DADDR(mp, fsbno);
879 	error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp, d,
880 				   mp->m_bsize, 0, &bp, ops);
881 	if (error)
882 		return error;
883 	if (bp)
884 		xfs_buf_set_ref(bp, refval);
885 	*bpp = bp;
886 	return 0;
887 }
888 
889 /*
890  * Read-ahead the block, don't wait for it, don't return a buffer.
891  * Long-form addressing.
892  */
893 /* ARGSUSED */
894 void
xfs_btree_reada_bufl(struct xfs_mount * mp,xfs_fsblock_t fsbno,xfs_extlen_t count,const struct xfs_buf_ops * ops)895 xfs_btree_reada_bufl(
896 	struct xfs_mount	*mp,		/* file system mount point */
897 	xfs_fsblock_t		fsbno,		/* file system block number */
898 	xfs_extlen_t		count,		/* count of filesystem blocks */
899 	const struct xfs_buf_ops *ops)
900 {
901 	xfs_daddr_t		d;
902 
903 	ASSERT(fsbno != NULLFSBLOCK);
904 	d = XFS_FSB_TO_DADDR(mp, fsbno);
905 	xfs_buf_readahead(mp->m_ddev_targp, d, mp->m_bsize * count, ops);
906 }
907 
908 /*
909  * Read-ahead the block, don't wait for it, don't return a buffer.
910  * Short-form addressing.
911  */
912 /* ARGSUSED */
913 void
xfs_btree_reada_bufs(struct xfs_mount * mp,xfs_agnumber_t agno,xfs_agblock_t agbno,xfs_extlen_t count,const struct xfs_buf_ops * ops)914 xfs_btree_reada_bufs(
915 	struct xfs_mount	*mp,		/* file system mount point */
916 	xfs_agnumber_t		agno,		/* allocation group number */
917 	xfs_agblock_t		agbno,		/* allocation group block number */
918 	xfs_extlen_t		count,		/* count of filesystem blocks */
919 	const struct xfs_buf_ops *ops)
920 {
921 	xfs_daddr_t		d;
922 
923 	ASSERT(agno != NULLAGNUMBER);
924 	ASSERT(agbno != NULLAGBLOCK);
925 	d = XFS_AGB_TO_DADDR(mp, agno, agbno);
926 	xfs_buf_readahead(mp->m_ddev_targp, d, mp->m_bsize * count, ops);
927 }
928 
929 STATIC int
xfs_btree_readahead_lblock(struct xfs_btree_cur * cur,int lr,struct xfs_btree_block * block)930 xfs_btree_readahead_lblock(
931 	struct xfs_btree_cur	*cur,
932 	int			lr,
933 	struct xfs_btree_block	*block)
934 {
935 	int			rval = 0;
936 	xfs_fsblock_t		left = be64_to_cpu(block->bb_u.l.bb_leftsib);
937 	xfs_fsblock_t		right = be64_to_cpu(block->bb_u.l.bb_rightsib);
938 
939 	if ((lr & XFS_BTCUR_LEFTRA) && left != NULLFSBLOCK) {
940 		xfs_btree_reada_bufl(cur->bc_mp, left, 1,
941 				     cur->bc_ops->buf_ops);
942 		rval++;
943 	}
944 
945 	if ((lr & XFS_BTCUR_RIGHTRA) && right != NULLFSBLOCK) {
946 		xfs_btree_reada_bufl(cur->bc_mp, right, 1,
947 				     cur->bc_ops->buf_ops);
948 		rval++;
949 	}
950 
951 	return rval;
952 }
953 
954 STATIC int
xfs_btree_readahead_sblock(struct xfs_btree_cur * cur,int lr,struct xfs_btree_block * block)955 xfs_btree_readahead_sblock(
956 	struct xfs_btree_cur	*cur,
957 	int			lr,
958 	struct xfs_btree_block *block)
959 {
960 	int			rval = 0;
961 	xfs_agblock_t		left = be32_to_cpu(block->bb_u.s.bb_leftsib);
962 	xfs_agblock_t		right = be32_to_cpu(block->bb_u.s.bb_rightsib);
963 
964 
965 	if ((lr & XFS_BTCUR_LEFTRA) && left != NULLAGBLOCK) {
966 		xfs_btree_reada_bufs(cur->bc_mp, cur->bc_ag.pag->pag_agno,
967 				     left, 1, cur->bc_ops->buf_ops);
968 		rval++;
969 	}
970 
971 	if ((lr & XFS_BTCUR_RIGHTRA) && right != NULLAGBLOCK) {
972 		xfs_btree_reada_bufs(cur->bc_mp, cur->bc_ag.pag->pag_agno,
973 				     right, 1, cur->bc_ops->buf_ops);
974 		rval++;
975 	}
976 
977 	return rval;
978 }
979 
980 /*
981  * Read-ahead btree blocks, at the given level.
982  * Bits in lr are set from XFS_BTCUR_{LEFT,RIGHT}RA.
983  */
984 STATIC int
xfs_btree_readahead(struct xfs_btree_cur * cur,int lev,int lr)985 xfs_btree_readahead(
986 	struct xfs_btree_cur	*cur,		/* btree cursor */
987 	int			lev,		/* level in btree */
988 	int			lr)		/* left/right bits */
989 {
990 	struct xfs_btree_block	*block;
991 
992 	/*
993 	 * No readahead needed if we are at the root level and the
994 	 * btree root is stored in the inode.
995 	 */
996 	if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
997 	    (lev == cur->bc_nlevels - 1))
998 		return 0;
999 
1000 	if ((cur->bc_levels[lev].ra | lr) == cur->bc_levels[lev].ra)
1001 		return 0;
1002 
1003 	cur->bc_levels[lev].ra |= lr;
1004 	block = XFS_BUF_TO_BLOCK(cur->bc_levels[lev].bp);
1005 
1006 	if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
1007 		return xfs_btree_readahead_lblock(cur, lr, block);
1008 	return xfs_btree_readahead_sblock(cur, lr, block);
1009 }
1010 
1011 STATIC int
xfs_btree_ptr_to_daddr(struct xfs_btree_cur * cur,const union xfs_btree_ptr * ptr,xfs_daddr_t * daddr)1012 xfs_btree_ptr_to_daddr(
1013 	struct xfs_btree_cur		*cur,
1014 	const union xfs_btree_ptr	*ptr,
1015 	xfs_daddr_t			*daddr)
1016 {
1017 	xfs_fsblock_t		fsbno;
1018 	xfs_agblock_t		agbno;
1019 	int			error;
1020 
1021 	error = xfs_btree_check_ptr(cur, ptr, 0, 1);
1022 	if (error)
1023 		return error;
1024 
1025 	if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
1026 		fsbno = be64_to_cpu(ptr->l);
1027 		*daddr = XFS_FSB_TO_DADDR(cur->bc_mp, fsbno);
1028 	} else {
1029 		agbno = be32_to_cpu(ptr->s);
1030 		*daddr = XFS_AGB_TO_DADDR(cur->bc_mp, cur->bc_ag.pag->pag_agno,
1031 				agbno);
1032 	}
1033 
1034 	return 0;
1035 }
1036 
1037 /*
1038  * Readahead @count btree blocks at the given @ptr location.
1039  *
1040  * We don't need to care about long or short form btrees here as we have a
1041  * method of converting the ptr directly to a daddr available to us.
1042  */
1043 STATIC void
xfs_btree_readahead_ptr(struct xfs_btree_cur * cur,union xfs_btree_ptr * ptr,xfs_extlen_t count)1044 xfs_btree_readahead_ptr(
1045 	struct xfs_btree_cur	*cur,
1046 	union xfs_btree_ptr	*ptr,
1047 	xfs_extlen_t		count)
1048 {
1049 	xfs_daddr_t		daddr;
1050 
1051 	if (xfs_btree_ptr_to_daddr(cur, ptr, &daddr))
1052 		return;
1053 	xfs_buf_readahead(cur->bc_mp->m_ddev_targp, daddr,
1054 			  cur->bc_mp->m_bsize * count, cur->bc_ops->buf_ops);
1055 }
1056 
1057 /*
1058  * Set the buffer for level "lev" in the cursor to bp, releasing
1059  * any previous buffer.
1060  */
1061 STATIC void
xfs_btree_setbuf(struct xfs_btree_cur * cur,int lev,struct xfs_buf * bp)1062 xfs_btree_setbuf(
1063 	struct xfs_btree_cur	*cur,	/* btree cursor */
1064 	int			lev,	/* level in btree */
1065 	struct xfs_buf		*bp)	/* new buffer to set */
1066 {
1067 	struct xfs_btree_block	*b;	/* btree block */
1068 
1069 	if (cur->bc_levels[lev].bp)
1070 		xfs_trans_brelse(cur->bc_tp, cur->bc_levels[lev].bp);
1071 	cur->bc_levels[lev].bp = bp;
1072 	cur->bc_levels[lev].ra = 0;
1073 
1074 	b = XFS_BUF_TO_BLOCK(bp);
1075 	if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
1076 		if (b->bb_u.l.bb_leftsib == cpu_to_be64(NULLFSBLOCK))
1077 			cur->bc_levels[lev].ra |= XFS_BTCUR_LEFTRA;
1078 		if (b->bb_u.l.bb_rightsib == cpu_to_be64(NULLFSBLOCK))
1079 			cur->bc_levels[lev].ra |= XFS_BTCUR_RIGHTRA;
1080 	} else {
1081 		if (b->bb_u.s.bb_leftsib == cpu_to_be32(NULLAGBLOCK))
1082 			cur->bc_levels[lev].ra |= XFS_BTCUR_LEFTRA;
1083 		if (b->bb_u.s.bb_rightsib == cpu_to_be32(NULLAGBLOCK))
1084 			cur->bc_levels[lev].ra |= XFS_BTCUR_RIGHTRA;
1085 	}
1086 }
1087 
1088 bool
xfs_btree_ptr_is_null(struct xfs_btree_cur * cur,const union xfs_btree_ptr * ptr)1089 xfs_btree_ptr_is_null(
1090 	struct xfs_btree_cur		*cur,
1091 	const union xfs_btree_ptr	*ptr)
1092 {
1093 	if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
1094 		return ptr->l == cpu_to_be64(NULLFSBLOCK);
1095 	else
1096 		return ptr->s == cpu_to_be32(NULLAGBLOCK);
1097 }
1098 
1099 void
xfs_btree_set_ptr_null(struct xfs_btree_cur * cur,union xfs_btree_ptr * ptr)1100 xfs_btree_set_ptr_null(
1101 	struct xfs_btree_cur	*cur,
1102 	union xfs_btree_ptr	*ptr)
1103 {
1104 	if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
1105 		ptr->l = cpu_to_be64(NULLFSBLOCK);
1106 	else
1107 		ptr->s = cpu_to_be32(NULLAGBLOCK);
1108 }
1109 
1110 /*
1111  * Get/set/init sibling pointers
1112  */
1113 void
xfs_btree_get_sibling(struct xfs_btree_cur * cur,struct xfs_btree_block * block,union xfs_btree_ptr * ptr,int lr)1114 xfs_btree_get_sibling(
1115 	struct xfs_btree_cur	*cur,
1116 	struct xfs_btree_block	*block,
1117 	union xfs_btree_ptr	*ptr,
1118 	int			lr)
1119 {
1120 	ASSERT(lr == XFS_BB_LEFTSIB || lr == XFS_BB_RIGHTSIB);
1121 
1122 	if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
1123 		if (lr == XFS_BB_RIGHTSIB)
1124 			ptr->l = block->bb_u.l.bb_rightsib;
1125 		else
1126 			ptr->l = block->bb_u.l.bb_leftsib;
1127 	} else {
1128 		if (lr == XFS_BB_RIGHTSIB)
1129 			ptr->s = block->bb_u.s.bb_rightsib;
1130 		else
1131 			ptr->s = block->bb_u.s.bb_leftsib;
1132 	}
1133 }
1134 
1135 void
xfs_btree_set_sibling(struct xfs_btree_cur * cur,struct xfs_btree_block * block,const union xfs_btree_ptr * ptr,int lr)1136 xfs_btree_set_sibling(
1137 	struct xfs_btree_cur		*cur,
1138 	struct xfs_btree_block		*block,
1139 	const union xfs_btree_ptr	*ptr,
1140 	int				lr)
1141 {
1142 	ASSERT(lr == XFS_BB_LEFTSIB || lr == XFS_BB_RIGHTSIB);
1143 
1144 	if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
1145 		if (lr == XFS_BB_RIGHTSIB)
1146 			block->bb_u.l.bb_rightsib = ptr->l;
1147 		else
1148 			block->bb_u.l.bb_leftsib = ptr->l;
1149 	} else {
1150 		if (lr == XFS_BB_RIGHTSIB)
1151 			block->bb_u.s.bb_rightsib = ptr->s;
1152 		else
1153 			block->bb_u.s.bb_leftsib = ptr->s;
1154 	}
1155 }
1156 
1157 void
xfs_btree_init_block_int(struct xfs_mount * mp,struct xfs_btree_block * buf,xfs_daddr_t blkno,xfs_btnum_t btnum,__u16 level,__u16 numrecs,__u64 owner,unsigned int flags)1158 xfs_btree_init_block_int(
1159 	struct xfs_mount	*mp,
1160 	struct xfs_btree_block	*buf,
1161 	xfs_daddr_t		blkno,
1162 	xfs_btnum_t		btnum,
1163 	__u16			level,
1164 	__u16			numrecs,
1165 	__u64			owner,
1166 	unsigned int		flags)
1167 {
1168 	int			crc = xfs_has_crc(mp);
1169 	__u32			magic = xfs_btree_magic(crc, btnum);
1170 
1171 	buf->bb_magic = cpu_to_be32(magic);
1172 	buf->bb_level = cpu_to_be16(level);
1173 	buf->bb_numrecs = cpu_to_be16(numrecs);
1174 
1175 	if (flags & XFS_BTREE_LONG_PTRS) {
1176 		buf->bb_u.l.bb_leftsib = cpu_to_be64(NULLFSBLOCK);
1177 		buf->bb_u.l.bb_rightsib = cpu_to_be64(NULLFSBLOCK);
1178 		if (crc) {
1179 			buf->bb_u.l.bb_blkno = cpu_to_be64(blkno);
1180 			buf->bb_u.l.bb_owner = cpu_to_be64(owner);
1181 			uuid_copy(&buf->bb_u.l.bb_uuid, &mp->m_sb.sb_meta_uuid);
1182 			buf->bb_u.l.bb_pad = 0;
1183 			buf->bb_u.l.bb_lsn = 0;
1184 		}
1185 	} else {
1186 		/* owner is a 32 bit value on short blocks */
1187 		__u32 __owner = (__u32)owner;
1188 
1189 		buf->bb_u.s.bb_leftsib = cpu_to_be32(NULLAGBLOCK);
1190 		buf->bb_u.s.bb_rightsib = cpu_to_be32(NULLAGBLOCK);
1191 		if (crc) {
1192 			buf->bb_u.s.bb_blkno = cpu_to_be64(blkno);
1193 			buf->bb_u.s.bb_owner = cpu_to_be32(__owner);
1194 			uuid_copy(&buf->bb_u.s.bb_uuid, &mp->m_sb.sb_meta_uuid);
1195 			buf->bb_u.s.bb_lsn = 0;
1196 		}
1197 	}
1198 }
1199 
1200 void
xfs_btree_init_block(struct xfs_mount * mp,struct xfs_buf * bp,xfs_btnum_t btnum,__u16 level,__u16 numrecs,__u64 owner)1201 xfs_btree_init_block(
1202 	struct xfs_mount *mp,
1203 	struct xfs_buf	*bp,
1204 	xfs_btnum_t	btnum,
1205 	__u16		level,
1206 	__u16		numrecs,
1207 	__u64		owner)
1208 {
1209 	xfs_btree_init_block_int(mp, XFS_BUF_TO_BLOCK(bp), xfs_buf_daddr(bp),
1210 				 btnum, level, numrecs, owner, 0);
1211 }
1212 
1213 void
xfs_btree_init_block_cur(struct xfs_btree_cur * cur,struct xfs_buf * bp,int level,int numrecs)1214 xfs_btree_init_block_cur(
1215 	struct xfs_btree_cur	*cur,
1216 	struct xfs_buf		*bp,
1217 	int			level,
1218 	int			numrecs)
1219 {
1220 	__u64			owner;
1221 
1222 	/*
1223 	 * we can pull the owner from the cursor right now as the different
1224 	 * owners align directly with the pointer size of the btree. This may
1225 	 * change in future, but is safe for current users of the generic btree
1226 	 * code.
1227 	 */
1228 	if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
1229 		owner = cur->bc_ino.ip->i_ino;
1230 	else
1231 		owner = cur->bc_ag.pag->pag_agno;
1232 
1233 	xfs_btree_init_block_int(cur->bc_mp, XFS_BUF_TO_BLOCK(bp),
1234 				xfs_buf_daddr(bp), cur->bc_btnum, level,
1235 				numrecs, owner, cur->bc_flags);
1236 }
1237 
1238 /*
1239  * Return true if ptr is the last record in the btree and
1240  * we need to track updates to this record.  The decision
1241  * will be further refined in the update_lastrec method.
1242  */
1243 STATIC int
xfs_btree_is_lastrec(struct xfs_btree_cur * cur,struct xfs_btree_block * block,int level)1244 xfs_btree_is_lastrec(
1245 	struct xfs_btree_cur	*cur,
1246 	struct xfs_btree_block	*block,
1247 	int			level)
1248 {
1249 	union xfs_btree_ptr	ptr;
1250 
1251 	if (level > 0)
1252 		return 0;
1253 	if (!(cur->bc_flags & XFS_BTREE_LASTREC_UPDATE))
1254 		return 0;
1255 
1256 	xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
1257 	if (!xfs_btree_ptr_is_null(cur, &ptr))
1258 		return 0;
1259 	return 1;
1260 }
1261 
1262 STATIC void
xfs_btree_buf_to_ptr(struct xfs_btree_cur * cur,struct xfs_buf * bp,union xfs_btree_ptr * ptr)1263 xfs_btree_buf_to_ptr(
1264 	struct xfs_btree_cur	*cur,
1265 	struct xfs_buf		*bp,
1266 	union xfs_btree_ptr	*ptr)
1267 {
1268 	if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
1269 		ptr->l = cpu_to_be64(XFS_DADDR_TO_FSB(cur->bc_mp,
1270 					xfs_buf_daddr(bp)));
1271 	else {
1272 		ptr->s = cpu_to_be32(xfs_daddr_to_agbno(cur->bc_mp,
1273 					xfs_buf_daddr(bp)));
1274 	}
1275 }
1276 
1277 STATIC void
xfs_btree_set_refs(struct xfs_btree_cur * cur,struct xfs_buf * bp)1278 xfs_btree_set_refs(
1279 	struct xfs_btree_cur	*cur,
1280 	struct xfs_buf		*bp)
1281 {
1282 	switch (cur->bc_btnum) {
1283 	case XFS_BTNUM_BNO:
1284 	case XFS_BTNUM_CNT:
1285 		xfs_buf_set_ref(bp, XFS_ALLOC_BTREE_REF);
1286 		break;
1287 	case XFS_BTNUM_INO:
1288 	case XFS_BTNUM_FINO:
1289 		xfs_buf_set_ref(bp, XFS_INO_BTREE_REF);
1290 		break;
1291 	case XFS_BTNUM_BMAP:
1292 		xfs_buf_set_ref(bp, XFS_BMAP_BTREE_REF);
1293 		break;
1294 	case XFS_BTNUM_RMAP:
1295 		xfs_buf_set_ref(bp, XFS_RMAP_BTREE_REF);
1296 		break;
1297 	case XFS_BTNUM_REFC:
1298 		xfs_buf_set_ref(bp, XFS_REFC_BTREE_REF);
1299 		break;
1300 	default:
1301 		ASSERT(0);
1302 	}
1303 }
1304 
1305 int
xfs_btree_get_buf_block(struct xfs_btree_cur * cur,const union xfs_btree_ptr * ptr,struct xfs_btree_block ** block,struct xfs_buf ** bpp)1306 xfs_btree_get_buf_block(
1307 	struct xfs_btree_cur		*cur,
1308 	const union xfs_btree_ptr	*ptr,
1309 	struct xfs_btree_block		**block,
1310 	struct xfs_buf			**bpp)
1311 {
1312 	struct xfs_mount	*mp = cur->bc_mp;
1313 	xfs_daddr_t		d;
1314 	int			error;
1315 
1316 	error = xfs_btree_ptr_to_daddr(cur, ptr, &d);
1317 	if (error)
1318 		return error;
1319 	error = xfs_trans_get_buf(cur->bc_tp, mp->m_ddev_targp, d, mp->m_bsize,
1320 			0, bpp);
1321 	if (error)
1322 		return error;
1323 
1324 	(*bpp)->b_ops = cur->bc_ops->buf_ops;
1325 	*block = XFS_BUF_TO_BLOCK(*bpp);
1326 	return 0;
1327 }
1328 
1329 /*
1330  * Read in the buffer at the given ptr and return the buffer and
1331  * the block pointer within the buffer.
1332  */
1333 STATIC int
xfs_btree_read_buf_block(struct xfs_btree_cur * cur,const union xfs_btree_ptr * ptr,int flags,struct xfs_btree_block ** block,struct xfs_buf ** bpp)1334 xfs_btree_read_buf_block(
1335 	struct xfs_btree_cur		*cur,
1336 	const union xfs_btree_ptr	*ptr,
1337 	int				flags,
1338 	struct xfs_btree_block		**block,
1339 	struct xfs_buf			**bpp)
1340 {
1341 	struct xfs_mount	*mp = cur->bc_mp;
1342 	xfs_daddr_t		d;
1343 	int			error;
1344 
1345 	/* need to sort out how callers deal with failures first */
1346 	ASSERT(!(flags & XBF_TRYLOCK));
1347 
1348 	error = xfs_btree_ptr_to_daddr(cur, ptr, &d);
1349 	if (error)
1350 		return error;
1351 	error = xfs_trans_read_buf(mp, cur->bc_tp, mp->m_ddev_targp, d,
1352 				   mp->m_bsize, flags, bpp,
1353 				   cur->bc_ops->buf_ops);
1354 	if (error)
1355 		return error;
1356 
1357 	xfs_btree_set_refs(cur, *bpp);
1358 	*block = XFS_BUF_TO_BLOCK(*bpp);
1359 	return 0;
1360 }
1361 
1362 /*
1363  * Copy keys from one btree block to another.
1364  */
1365 void
xfs_btree_copy_keys(struct xfs_btree_cur * cur,union xfs_btree_key * dst_key,const union xfs_btree_key * src_key,int numkeys)1366 xfs_btree_copy_keys(
1367 	struct xfs_btree_cur		*cur,
1368 	union xfs_btree_key		*dst_key,
1369 	const union xfs_btree_key	*src_key,
1370 	int				numkeys)
1371 {
1372 	ASSERT(numkeys >= 0);
1373 	memcpy(dst_key, src_key, numkeys * cur->bc_ops->key_len);
1374 }
1375 
1376 /*
1377  * Copy records from one btree block to another.
1378  */
1379 STATIC void
xfs_btree_copy_recs(struct xfs_btree_cur * cur,union xfs_btree_rec * dst_rec,union xfs_btree_rec * src_rec,int numrecs)1380 xfs_btree_copy_recs(
1381 	struct xfs_btree_cur	*cur,
1382 	union xfs_btree_rec	*dst_rec,
1383 	union xfs_btree_rec	*src_rec,
1384 	int			numrecs)
1385 {
1386 	ASSERT(numrecs >= 0);
1387 	memcpy(dst_rec, src_rec, numrecs * cur->bc_ops->rec_len);
1388 }
1389 
1390 /*
1391  * Copy block pointers from one btree block to another.
1392  */
1393 void
xfs_btree_copy_ptrs(struct xfs_btree_cur * cur,union xfs_btree_ptr * dst_ptr,const union xfs_btree_ptr * src_ptr,int numptrs)1394 xfs_btree_copy_ptrs(
1395 	struct xfs_btree_cur	*cur,
1396 	union xfs_btree_ptr	*dst_ptr,
1397 	const union xfs_btree_ptr *src_ptr,
1398 	int			numptrs)
1399 {
1400 	ASSERT(numptrs >= 0);
1401 	memcpy(dst_ptr, src_ptr, numptrs * xfs_btree_ptr_len(cur));
1402 }
1403 
1404 /*
1405  * Shift keys one index left/right inside a single btree block.
1406  */
1407 STATIC void
xfs_btree_shift_keys(struct xfs_btree_cur * cur,union xfs_btree_key * key,int dir,int numkeys)1408 xfs_btree_shift_keys(
1409 	struct xfs_btree_cur	*cur,
1410 	union xfs_btree_key	*key,
1411 	int			dir,
1412 	int			numkeys)
1413 {
1414 	char			*dst_key;
1415 
1416 	ASSERT(numkeys >= 0);
1417 	ASSERT(dir == 1 || dir == -1);
1418 
1419 	dst_key = (char *)key + (dir * cur->bc_ops->key_len);
1420 	memmove(dst_key, key, numkeys * cur->bc_ops->key_len);
1421 }
1422 
1423 /*
1424  * Shift records one index left/right inside a single btree block.
1425  */
1426 STATIC void
xfs_btree_shift_recs(struct xfs_btree_cur * cur,union xfs_btree_rec * rec,int dir,int numrecs)1427 xfs_btree_shift_recs(
1428 	struct xfs_btree_cur	*cur,
1429 	union xfs_btree_rec	*rec,
1430 	int			dir,
1431 	int			numrecs)
1432 {
1433 	char			*dst_rec;
1434 
1435 	ASSERT(numrecs >= 0);
1436 	ASSERT(dir == 1 || dir == -1);
1437 
1438 	dst_rec = (char *)rec + (dir * cur->bc_ops->rec_len);
1439 	memmove(dst_rec, rec, numrecs * cur->bc_ops->rec_len);
1440 }
1441 
1442 /*
1443  * Shift block pointers one index left/right inside a single btree block.
1444  */
1445 STATIC void
xfs_btree_shift_ptrs(struct xfs_btree_cur * cur,union xfs_btree_ptr * ptr,int dir,int numptrs)1446 xfs_btree_shift_ptrs(
1447 	struct xfs_btree_cur	*cur,
1448 	union xfs_btree_ptr	*ptr,
1449 	int			dir,
1450 	int			numptrs)
1451 {
1452 	char			*dst_ptr;
1453 
1454 	ASSERT(numptrs >= 0);
1455 	ASSERT(dir == 1 || dir == -1);
1456 
1457 	dst_ptr = (char *)ptr + (dir * xfs_btree_ptr_len(cur));
1458 	memmove(dst_ptr, ptr, numptrs * xfs_btree_ptr_len(cur));
1459 }
1460 
1461 /*
1462  * Log key values from the btree block.
1463  */
1464 STATIC void
xfs_btree_log_keys(struct xfs_btree_cur * cur,struct xfs_buf * bp,int first,int last)1465 xfs_btree_log_keys(
1466 	struct xfs_btree_cur	*cur,
1467 	struct xfs_buf		*bp,
1468 	int			first,
1469 	int			last)
1470 {
1471 
1472 	if (bp) {
1473 		xfs_trans_buf_set_type(cur->bc_tp, bp, XFS_BLFT_BTREE_BUF);
1474 		xfs_trans_log_buf(cur->bc_tp, bp,
1475 				  xfs_btree_key_offset(cur, first),
1476 				  xfs_btree_key_offset(cur, last + 1) - 1);
1477 	} else {
1478 		xfs_trans_log_inode(cur->bc_tp, cur->bc_ino.ip,
1479 				xfs_ilog_fbroot(cur->bc_ino.whichfork));
1480 	}
1481 }
1482 
1483 /*
1484  * Log record values from the btree block.
1485  */
1486 void
xfs_btree_log_recs(struct xfs_btree_cur * cur,struct xfs_buf * bp,int first,int last)1487 xfs_btree_log_recs(
1488 	struct xfs_btree_cur	*cur,
1489 	struct xfs_buf		*bp,
1490 	int			first,
1491 	int			last)
1492 {
1493 
1494 	xfs_trans_buf_set_type(cur->bc_tp, bp, XFS_BLFT_BTREE_BUF);
1495 	xfs_trans_log_buf(cur->bc_tp, bp,
1496 			  xfs_btree_rec_offset(cur, first),
1497 			  xfs_btree_rec_offset(cur, last + 1) - 1);
1498 
1499 }
1500 
1501 /*
1502  * Log block pointer fields from a btree block (nonleaf).
1503  */
1504 STATIC void
xfs_btree_log_ptrs(struct xfs_btree_cur * cur,struct xfs_buf * bp,int first,int last)1505 xfs_btree_log_ptrs(
1506 	struct xfs_btree_cur	*cur,	/* btree cursor */
1507 	struct xfs_buf		*bp,	/* buffer containing btree block */
1508 	int			first,	/* index of first pointer to log */
1509 	int			last)	/* index of last pointer to log */
1510 {
1511 
1512 	if (bp) {
1513 		struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
1514 		int			level = xfs_btree_get_level(block);
1515 
1516 		xfs_trans_buf_set_type(cur->bc_tp, bp, XFS_BLFT_BTREE_BUF);
1517 		xfs_trans_log_buf(cur->bc_tp, bp,
1518 				xfs_btree_ptr_offset(cur, first, level),
1519 				xfs_btree_ptr_offset(cur, last + 1, level) - 1);
1520 	} else {
1521 		xfs_trans_log_inode(cur->bc_tp, cur->bc_ino.ip,
1522 			xfs_ilog_fbroot(cur->bc_ino.whichfork));
1523 	}
1524 
1525 }
1526 
1527 /*
1528  * Log fields from a btree block header.
1529  */
1530 void
xfs_btree_log_block(struct xfs_btree_cur * cur,struct xfs_buf * bp,uint32_t fields)1531 xfs_btree_log_block(
1532 	struct xfs_btree_cur	*cur,	/* btree cursor */
1533 	struct xfs_buf		*bp,	/* buffer containing btree block */
1534 	uint32_t		fields)	/* mask of fields: XFS_BB_... */
1535 {
1536 	int			first;	/* first byte offset logged */
1537 	int			last;	/* last byte offset logged */
1538 	static const short	soffsets[] = {	/* table of offsets (short) */
1539 		offsetof(struct xfs_btree_block, bb_magic),
1540 		offsetof(struct xfs_btree_block, bb_level),
1541 		offsetof(struct xfs_btree_block, bb_numrecs),
1542 		offsetof(struct xfs_btree_block, bb_u.s.bb_leftsib),
1543 		offsetof(struct xfs_btree_block, bb_u.s.bb_rightsib),
1544 		offsetof(struct xfs_btree_block, bb_u.s.bb_blkno),
1545 		offsetof(struct xfs_btree_block, bb_u.s.bb_lsn),
1546 		offsetof(struct xfs_btree_block, bb_u.s.bb_uuid),
1547 		offsetof(struct xfs_btree_block, bb_u.s.bb_owner),
1548 		offsetof(struct xfs_btree_block, bb_u.s.bb_crc),
1549 		XFS_BTREE_SBLOCK_CRC_LEN
1550 	};
1551 	static const short	loffsets[] = {	/* table of offsets (long) */
1552 		offsetof(struct xfs_btree_block, bb_magic),
1553 		offsetof(struct xfs_btree_block, bb_level),
1554 		offsetof(struct xfs_btree_block, bb_numrecs),
1555 		offsetof(struct xfs_btree_block, bb_u.l.bb_leftsib),
1556 		offsetof(struct xfs_btree_block, bb_u.l.bb_rightsib),
1557 		offsetof(struct xfs_btree_block, bb_u.l.bb_blkno),
1558 		offsetof(struct xfs_btree_block, bb_u.l.bb_lsn),
1559 		offsetof(struct xfs_btree_block, bb_u.l.bb_uuid),
1560 		offsetof(struct xfs_btree_block, bb_u.l.bb_owner),
1561 		offsetof(struct xfs_btree_block, bb_u.l.bb_crc),
1562 		offsetof(struct xfs_btree_block, bb_u.l.bb_pad),
1563 		XFS_BTREE_LBLOCK_CRC_LEN
1564 	};
1565 
1566 	if (bp) {
1567 		int nbits;
1568 
1569 		if (cur->bc_flags & XFS_BTREE_CRC_BLOCKS) {
1570 			/*
1571 			 * We don't log the CRC when updating a btree
1572 			 * block but instead recreate it during log
1573 			 * recovery.  As the log buffers have checksums
1574 			 * of their own this is safe and avoids logging a crc
1575 			 * update in a lot of places.
1576 			 */
1577 			if (fields == XFS_BB_ALL_BITS)
1578 				fields = XFS_BB_ALL_BITS_CRC;
1579 			nbits = XFS_BB_NUM_BITS_CRC;
1580 		} else {
1581 			nbits = XFS_BB_NUM_BITS;
1582 		}
1583 		xfs_btree_offsets(fields,
1584 				  (cur->bc_flags & XFS_BTREE_LONG_PTRS) ?
1585 					loffsets : soffsets,
1586 				  nbits, &first, &last);
1587 		xfs_trans_buf_set_type(cur->bc_tp, bp, XFS_BLFT_BTREE_BUF);
1588 		xfs_trans_log_buf(cur->bc_tp, bp, first, last);
1589 	} else {
1590 		xfs_trans_log_inode(cur->bc_tp, cur->bc_ino.ip,
1591 			xfs_ilog_fbroot(cur->bc_ino.whichfork));
1592 	}
1593 }
1594 
1595 /*
1596  * Increment cursor by one record at the level.
1597  * For nonzero levels the leaf-ward information is untouched.
1598  */
1599 int						/* error */
xfs_btree_increment(struct xfs_btree_cur * cur,int level,int * stat)1600 xfs_btree_increment(
1601 	struct xfs_btree_cur	*cur,
1602 	int			level,
1603 	int			*stat)		/* success/failure */
1604 {
1605 	struct xfs_btree_block	*block;
1606 	union xfs_btree_ptr	ptr;
1607 	struct xfs_buf		*bp;
1608 	int			error;		/* error return value */
1609 	int			lev;
1610 
1611 	ASSERT(level < cur->bc_nlevels);
1612 
1613 	/* Read-ahead to the right at this level. */
1614 	xfs_btree_readahead(cur, level, XFS_BTCUR_RIGHTRA);
1615 
1616 	/* Get a pointer to the btree block. */
1617 	block = xfs_btree_get_block(cur, level, &bp);
1618 
1619 #ifdef DEBUG
1620 	error = xfs_btree_check_block(cur, block, level, bp);
1621 	if (error)
1622 		goto error0;
1623 #endif
1624 
1625 	/* We're done if we remain in the block after the increment. */
1626 	if (++cur->bc_levels[level].ptr <= xfs_btree_get_numrecs(block))
1627 		goto out1;
1628 
1629 	/* Fail if we just went off the right edge of the tree. */
1630 	xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
1631 	if (xfs_btree_ptr_is_null(cur, &ptr))
1632 		goto out0;
1633 
1634 	XFS_BTREE_STATS_INC(cur, increment);
1635 
1636 	/*
1637 	 * March up the tree incrementing pointers.
1638 	 * Stop when we don't go off the right edge of a block.
1639 	 */
1640 	for (lev = level + 1; lev < cur->bc_nlevels; lev++) {
1641 		block = xfs_btree_get_block(cur, lev, &bp);
1642 
1643 #ifdef DEBUG
1644 		error = xfs_btree_check_block(cur, block, lev, bp);
1645 		if (error)
1646 			goto error0;
1647 #endif
1648 
1649 		if (++cur->bc_levels[lev].ptr <= xfs_btree_get_numrecs(block))
1650 			break;
1651 
1652 		/* Read-ahead the right block for the next loop. */
1653 		xfs_btree_readahead(cur, lev, XFS_BTCUR_RIGHTRA);
1654 	}
1655 
1656 	/*
1657 	 * If we went off the root then we are either seriously
1658 	 * confused or have the tree root in an inode.
1659 	 */
1660 	if (lev == cur->bc_nlevels) {
1661 		if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE)
1662 			goto out0;
1663 		ASSERT(0);
1664 		error = -EFSCORRUPTED;
1665 		goto error0;
1666 	}
1667 	ASSERT(lev < cur->bc_nlevels);
1668 
1669 	/*
1670 	 * Now walk back down the tree, fixing up the cursor's buffer
1671 	 * pointers and key numbers.
1672 	 */
1673 	for (block = xfs_btree_get_block(cur, lev, &bp); lev > level; ) {
1674 		union xfs_btree_ptr	*ptrp;
1675 
1676 		ptrp = xfs_btree_ptr_addr(cur, cur->bc_levels[lev].ptr, block);
1677 		--lev;
1678 		error = xfs_btree_read_buf_block(cur, ptrp, 0, &block, &bp);
1679 		if (error)
1680 			goto error0;
1681 
1682 		xfs_btree_setbuf(cur, lev, bp);
1683 		cur->bc_levels[lev].ptr = 1;
1684 	}
1685 out1:
1686 	*stat = 1;
1687 	return 0;
1688 
1689 out0:
1690 	*stat = 0;
1691 	return 0;
1692 
1693 error0:
1694 	return error;
1695 }
1696 
1697 /*
1698  * Decrement cursor by one record at the level.
1699  * For nonzero levels the leaf-ward information is untouched.
1700  */
1701 int						/* error */
xfs_btree_decrement(struct xfs_btree_cur * cur,int level,int * stat)1702 xfs_btree_decrement(
1703 	struct xfs_btree_cur	*cur,
1704 	int			level,
1705 	int			*stat)		/* success/failure */
1706 {
1707 	struct xfs_btree_block	*block;
1708 	struct xfs_buf		*bp;
1709 	int			error;		/* error return value */
1710 	int			lev;
1711 	union xfs_btree_ptr	ptr;
1712 
1713 	ASSERT(level < cur->bc_nlevels);
1714 
1715 	/* Read-ahead to the left at this level. */
1716 	xfs_btree_readahead(cur, level, XFS_BTCUR_LEFTRA);
1717 
1718 	/* We're done if we remain in the block after the decrement. */
1719 	if (--cur->bc_levels[level].ptr > 0)
1720 		goto out1;
1721 
1722 	/* Get a pointer to the btree block. */
1723 	block = xfs_btree_get_block(cur, level, &bp);
1724 
1725 #ifdef DEBUG
1726 	error = xfs_btree_check_block(cur, block, level, bp);
1727 	if (error)
1728 		goto error0;
1729 #endif
1730 
1731 	/* Fail if we just went off the left edge of the tree. */
1732 	xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_LEFTSIB);
1733 	if (xfs_btree_ptr_is_null(cur, &ptr))
1734 		goto out0;
1735 
1736 	XFS_BTREE_STATS_INC(cur, decrement);
1737 
1738 	/*
1739 	 * March up the tree decrementing pointers.
1740 	 * Stop when we don't go off the left edge of a block.
1741 	 */
1742 	for (lev = level + 1; lev < cur->bc_nlevels; lev++) {
1743 		if (--cur->bc_levels[lev].ptr > 0)
1744 			break;
1745 		/* Read-ahead the left block for the next loop. */
1746 		xfs_btree_readahead(cur, lev, XFS_BTCUR_LEFTRA);
1747 	}
1748 
1749 	/*
1750 	 * If we went off the root then we are seriously confused.
1751 	 * or the root of the tree is in an inode.
1752 	 */
1753 	if (lev == cur->bc_nlevels) {
1754 		if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE)
1755 			goto out0;
1756 		ASSERT(0);
1757 		error = -EFSCORRUPTED;
1758 		goto error0;
1759 	}
1760 	ASSERT(lev < cur->bc_nlevels);
1761 
1762 	/*
1763 	 * Now walk back down the tree, fixing up the cursor's buffer
1764 	 * pointers and key numbers.
1765 	 */
1766 	for (block = xfs_btree_get_block(cur, lev, &bp); lev > level; ) {
1767 		union xfs_btree_ptr	*ptrp;
1768 
1769 		ptrp = xfs_btree_ptr_addr(cur, cur->bc_levels[lev].ptr, block);
1770 		--lev;
1771 		error = xfs_btree_read_buf_block(cur, ptrp, 0, &block, &bp);
1772 		if (error)
1773 			goto error0;
1774 		xfs_btree_setbuf(cur, lev, bp);
1775 		cur->bc_levels[lev].ptr = xfs_btree_get_numrecs(block);
1776 	}
1777 out1:
1778 	*stat = 1;
1779 	return 0;
1780 
1781 out0:
1782 	*stat = 0;
1783 	return 0;
1784 
1785 error0:
1786 	return error;
1787 }
1788 
1789 int
xfs_btree_lookup_get_block(struct xfs_btree_cur * cur,int level,const union xfs_btree_ptr * pp,struct xfs_btree_block ** blkp)1790 xfs_btree_lookup_get_block(
1791 	struct xfs_btree_cur		*cur,	/* btree cursor */
1792 	int				level,	/* level in the btree */
1793 	const union xfs_btree_ptr	*pp,	/* ptr to btree block */
1794 	struct xfs_btree_block		**blkp) /* return btree block */
1795 {
1796 	struct xfs_buf		*bp;	/* buffer pointer for btree block */
1797 	xfs_daddr_t		daddr;
1798 	int			error = 0;
1799 
1800 	/* special case the root block if in an inode */
1801 	if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
1802 	    (level == cur->bc_nlevels - 1)) {
1803 		*blkp = xfs_btree_get_iroot(cur);
1804 		return 0;
1805 	}
1806 
1807 	/*
1808 	 * If the old buffer at this level for the disk address we are
1809 	 * looking for re-use it.
1810 	 *
1811 	 * Otherwise throw it away and get a new one.
1812 	 */
1813 	bp = cur->bc_levels[level].bp;
1814 	error = xfs_btree_ptr_to_daddr(cur, pp, &daddr);
1815 	if (error)
1816 		return error;
1817 	if (bp && xfs_buf_daddr(bp) == daddr) {
1818 		*blkp = XFS_BUF_TO_BLOCK(bp);
1819 		return 0;
1820 	}
1821 
1822 	error = xfs_btree_read_buf_block(cur, pp, 0, blkp, &bp);
1823 	if (error)
1824 		return error;
1825 
1826 	/* Check the inode owner since the verifiers don't. */
1827 	if (xfs_has_crc(cur->bc_mp) &&
1828 	    !(cur->bc_ino.flags & XFS_BTCUR_BMBT_INVALID_OWNER) &&
1829 	    (cur->bc_flags & XFS_BTREE_LONG_PTRS) &&
1830 	    be64_to_cpu((*blkp)->bb_u.l.bb_owner) !=
1831 			cur->bc_ino.ip->i_ino)
1832 		goto out_bad;
1833 
1834 	/* Did we get the level we were looking for? */
1835 	if (be16_to_cpu((*blkp)->bb_level) != level)
1836 		goto out_bad;
1837 
1838 	/* Check that internal nodes have at least one record. */
1839 	if (level != 0 && be16_to_cpu((*blkp)->bb_numrecs) == 0)
1840 		goto out_bad;
1841 
1842 	xfs_btree_setbuf(cur, level, bp);
1843 	return 0;
1844 
1845 out_bad:
1846 	*blkp = NULL;
1847 	xfs_buf_mark_corrupt(bp);
1848 	xfs_trans_brelse(cur->bc_tp, bp);
1849 	return -EFSCORRUPTED;
1850 }
1851 
1852 /*
1853  * Get current search key.  For level 0 we don't actually have a key
1854  * structure so we make one up from the record.  For all other levels
1855  * we just return the right key.
1856  */
1857 STATIC union xfs_btree_key *
xfs_lookup_get_search_key(struct xfs_btree_cur * cur,int level,int keyno,struct xfs_btree_block * block,union xfs_btree_key * kp)1858 xfs_lookup_get_search_key(
1859 	struct xfs_btree_cur	*cur,
1860 	int			level,
1861 	int			keyno,
1862 	struct xfs_btree_block	*block,
1863 	union xfs_btree_key	*kp)
1864 {
1865 	if (level == 0) {
1866 		cur->bc_ops->init_key_from_rec(kp,
1867 				xfs_btree_rec_addr(cur, keyno, block));
1868 		return kp;
1869 	}
1870 
1871 	return xfs_btree_key_addr(cur, keyno, block);
1872 }
1873 
1874 /*
1875  * Lookup the record.  The cursor is made to point to it, based on dir.
1876  * stat is set to 0 if can't find any such record, 1 for success.
1877  */
1878 int					/* error */
xfs_btree_lookup(struct xfs_btree_cur * cur,xfs_lookup_t dir,int * stat)1879 xfs_btree_lookup(
1880 	struct xfs_btree_cur	*cur,	/* btree cursor */
1881 	xfs_lookup_t		dir,	/* <=, ==, or >= */
1882 	int			*stat)	/* success/failure */
1883 {
1884 	struct xfs_btree_block	*block;	/* current btree block */
1885 	int64_t			diff;	/* difference for the current key */
1886 	int			error;	/* error return value */
1887 	int			keyno;	/* current key number */
1888 	int			level;	/* level in the btree */
1889 	union xfs_btree_ptr	*pp;	/* ptr to btree block */
1890 	union xfs_btree_ptr	ptr;	/* ptr to btree block */
1891 
1892 	XFS_BTREE_STATS_INC(cur, lookup);
1893 
1894 	/* No such thing as a zero-level tree. */
1895 	if (XFS_IS_CORRUPT(cur->bc_mp, cur->bc_nlevels == 0))
1896 		return -EFSCORRUPTED;
1897 
1898 	block = NULL;
1899 	keyno = 0;
1900 
1901 	/* initialise start pointer from cursor */
1902 	cur->bc_ops->init_ptr_from_cur(cur, &ptr);
1903 	pp = &ptr;
1904 
1905 	/*
1906 	 * Iterate over each level in the btree, starting at the root.
1907 	 * For each level above the leaves, find the key we need, based
1908 	 * on the lookup record, then follow the corresponding block
1909 	 * pointer down to the next level.
1910 	 */
1911 	for (level = cur->bc_nlevels - 1, diff = 1; level >= 0; level--) {
1912 		/* Get the block we need to do the lookup on. */
1913 		error = xfs_btree_lookup_get_block(cur, level, pp, &block);
1914 		if (error)
1915 			goto error0;
1916 
1917 		if (diff == 0) {
1918 			/*
1919 			 * If we already had a key match at a higher level, we
1920 			 * know we need to use the first entry in this block.
1921 			 */
1922 			keyno = 1;
1923 		} else {
1924 			/* Otherwise search this block. Do a binary search. */
1925 
1926 			int	high;	/* high entry number */
1927 			int	low;	/* low entry number */
1928 
1929 			/* Set low and high entry numbers, 1-based. */
1930 			low = 1;
1931 			high = xfs_btree_get_numrecs(block);
1932 			if (!high) {
1933 				/* Block is empty, must be an empty leaf. */
1934 				if (level != 0 || cur->bc_nlevels != 1) {
1935 					XFS_CORRUPTION_ERROR(__func__,
1936 							XFS_ERRLEVEL_LOW,
1937 							cur->bc_mp, block,
1938 							sizeof(*block));
1939 					return -EFSCORRUPTED;
1940 				}
1941 
1942 				cur->bc_levels[0].ptr = dir != XFS_LOOKUP_LE;
1943 				*stat = 0;
1944 				return 0;
1945 			}
1946 
1947 			/* Binary search the block. */
1948 			while (low <= high) {
1949 				union xfs_btree_key	key;
1950 				union xfs_btree_key	*kp;
1951 
1952 				XFS_BTREE_STATS_INC(cur, compare);
1953 
1954 				/* keyno is average of low and high. */
1955 				keyno = (low + high) >> 1;
1956 
1957 				/* Get current search key */
1958 				kp = xfs_lookup_get_search_key(cur, level,
1959 						keyno, block, &key);
1960 
1961 				/*
1962 				 * Compute difference to get next direction:
1963 				 *  - less than, move right
1964 				 *  - greater than, move left
1965 				 *  - equal, we're done
1966 				 */
1967 				diff = cur->bc_ops->key_diff(cur, kp);
1968 				if (diff < 0)
1969 					low = keyno + 1;
1970 				else if (diff > 0)
1971 					high = keyno - 1;
1972 				else
1973 					break;
1974 			}
1975 		}
1976 
1977 		/*
1978 		 * If there are more levels, set up for the next level
1979 		 * by getting the block number and filling in the cursor.
1980 		 */
1981 		if (level > 0) {
1982 			/*
1983 			 * If we moved left, need the previous key number,
1984 			 * unless there isn't one.
1985 			 */
1986 			if (diff > 0 && --keyno < 1)
1987 				keyno = 1;
1988 			pp = xfs_btree_ptr_addr(cur, keyno, block);
1989 
1990 			error = xfs_btree_debug_check_ptr(cur, pp, 0, level);
1991 			if (error)
1992 				goto error0;
1993 
1994 			cur->bc_levels[level].ptr = keyno;
1995 		}
1996 	}
1997 
1998 	/* Done with the search. See if we need to adjust the results. */
1999 	if (dir != XFS_LOOKUP_LE && diff < 0) {
2000 		keyno++;
2001 		/*
2002 		 * If ge search and we went off the end of the block, but it's
2003 		 * not the last block, we're in the wrong block.
2004 		 */
2005 		xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
2006 		if (dir == XFS_LOOKUP_GE &&
2007 		    keyno > xfs_btree_get_numrecs(block) &&
2008 		    !xfs_btree_ptr_is_null(cur, &ptr)) {
2009 			int	i;
2010 
2011 			cur->bc_levels[0].ptr = keyno;
2012 			error = xfs_btree_increment(cur, 0, &i);
2013 			if (error)
2014 				goto error0;
2015 			if (XFS_IS_CORRUPT(cur->bc_mp, i != 1))
2016 				return -EFSCORRUPTED;
2017 			*stat = 1;
2018 			return 0;
2019 		}
2020 	} else if (dir == XFS_LOOKUP_LE && diff > 0)
2021 		keyno--;
2022 	cur->bc_levels[0].ptr = keyno;
2023 
2024 	/* Return if we succeeded or not. */
2025 	if (keyno == 0 || keyno > xfs_btree_get_numrecs(block))
2026 		*stat = 0;
2027 	else if (dir != XFS_LOOKUP_EQ || diff == 0)
2028 		*stat = 1;
2029 	else
2030 		*stat = 0;
2031 	return 0;
2032 
2033 error0:
2034 	return error;
2035 }
2036 
2037 /* Find the high key storage area from a regular key. */
2038 union xfs_btree_key *
xfs_btree_high_key_from_key(struct xfs_btree_cur * cur,union xfs_btree_key * key)2039 xfs_btree_high_key_from_key(
2040 	struct xfs_btree_cur	*cur,
2041 	union xfs_btree_key	*key)
2042 {
2043 	ASSERT(cur->bc_flags & XFS_BTREE_OVERLAPPING);
2044 	return (union xfs_btree_key *)((char *)key +
2045 			(cur->bc_ops->key_len / 2));
2046 }
2047 
2048 /* Determine the low (and high if overlapped) keys of a leaf block */
2049 STATIC void
xfs_btree_get_leaf_keys(struct xfs_btree_cur * cur,struct xfs_btree_block * block,union xfs_btree_key * key)2050 xfs_btree_get_leaf_keys(
2051 	struct xfs_btree_cur	*cur,
2052 	struct xfs_btree_block	*block,
2053 	union xfs_btree_key	*key)
2054 {
2055 	union xfs_btree_key	max_hkey;
2056 	union xfs_btree_key	hkey;
2057 	union xfs_btree_rec	*rec;
2058 	union xfs_btree_key	*high;
2059 	int			n;
2060 
2061 	rec = xfs_btree_rec_addr(cur, 1, block);
2062 	cur->bc_ops->init_key_from_rec(key, rec);
2063 
2064 	if (cur->bc_flags & XFS_BTREE_OVERLAPPING) {
2065 
2066 		cur->bc_ops->init_high_key_from_rec(&max_hkey, rec);
2067 		for (n = 2; n <= xfs_btree_get_numrecs(block); n++) {
2068 			rec = xfs_btree_rec_addr(cur, n, block);
2069 			cur->bc_ops->init_high_key_from_rec(&hkey, rec);
2070 			if (xfs_btree_keycmp_gt(cur, &hkey, &max_hkey))
2071 				max_hkey = hkey;
2072 		}
2073 
2074 		high = xfs_btree_high_key_from_key(cur, key);
2075 		memcpy(high, &max_hkey, cur->bc_ops->key_len / 2);
2076 	}
2077 }
2078 
2079 /* Determine the low (and high if overlapped) keys of a node block */
2080 STATIC void
xfs_btree_get_node_keys(struct xfs_btree_cur * cur,struct xfs_btree_block * block,union xfs_btree_key * key)2081 xfs_btree_get_node_keys(
2082 	struct xfs_btree_cur	*cur,
2083 	struct xfs_btree_block	*block,
2084 	union xfs_btree_key	*key)
2085 {
2086 	union xfs_btree_key	*hkey;
2087 	union xfs_btree_key	*max_hkey;
2088 	union xfs_btree_key	*high;
2089 	int			n;
2090 
2091 	if (cur->bc_flags & XFS_BTREE_OVERLAPPING) {
2092 		memcpy(key, xfs_btree_key_addr(cur, 1, block),
2093 				cur->bc_ops->key_len / 2);
2094 
2095 		max_hkey = xfs_btree_high_key_addr(cur, 1, block);
2096 		for (n = 2; n <= xfs_btree_get_numrecs(block); n++) {
2097 			hkey = xfs_btree_high_key_addr(cur, n, block);
2098 			if (xfs_btree_keycmp_gt(cur, hkey, max_hkey))
2099 				max_hkey = hkey;
2100 		}
2101 
2102 		high = xfs_btree_high_key_from_key(cur, key);
2103 		memcpy(high, max_hkey, cur->bc_ops->key_len / 2);
2104 	} else {
2105 		memcpy(key, xfs_btree_key_addr(cur, 1, block),
2106 				cur->bc_ops->key_len);
2107 	}
2108 }
2109 
2110 /* Derive the keys for any btree block. */
2111 void
xfs_btree_get_keys(struct xfs_btree_cur * cur,struct xfs_btree_block * block,union xfs_btree_key * key)2112 xfs_btree_get_keys(
2113 	struct xfs_btree_cur	*cur,
2114 	struct xfs_btree_block	*block,
2115 	union xfs_btree_key	*key)
2116 {
2117 	if (be16_to_cpu(block->bb_level) == 0)
2118 		xfs_btree_get_leaf_keys(cur, block, key);
2119 	else
2120 		xfs_btree_get_node_keys(cur, block, key);
2121 }
2122 
2123 /*
2124  * Decide if we need to update the parent keys of a btree block.  For
2125  * a standard btree this is only necessary if we're updating the first
2126  * record/key.  For an overlapping btree, we must always update the
2127  * keys because the highest key can be in any of the records or keys
2128  * in the block.
2129  */
2130 static inline bool
xfs_btree_needs_key_update(struct xfs_btree_cur * cur,int ptr)2131 xfs_btree_needs_key_update(
2132 	struct xfs_btree_cur	*cur,
2133 	int			ptr)
2134 {
2135 	return (cur->bc_flags & XFS_BTREE_OVERLAPPING) || ptr == 1;
2136 }
2137 
2138 /*
2139  * Update the low and high parent keys of the given level, progressing
2140  * towards the root.  If force_all is false, stop if the keys for a given
2141  * level do not need updating.
2142  */
2143 STATIC int
__xfs_btree_updkeys(struct xfs_btree_cur * cur,int level,struct xfs_btree_block * block,struct xfs_buf * bp0,bool force_all)2144 __xfs_btree_updkeys(
2145 	struct xfs_btree_cur	*cur,
2146 	int			level,
2147 	struct xfs_btree_block	*block,
2148 	struct xfs_buf		*bp0,
2149 	bool			force_all)
2150 {
2151 	union xfs_btree_key	key;	/* keys from current level */
2152 	union xfs_btree_key	*lkey;	/* keys from the next level up */
2153 	union xfs_btree_key	*hkey;
2154 	union xfs_btree_key	*nlkey;	/* keys from the next level up */
2155 	union xfs_btree_key	*nhkey;
2156 	struct xfs_buf		*bp;
2157 	int			ptr;
2158 
2159 	ASSERT(cur->bc_flags & XFS_BTREE_OVERLAPPING);
2160 
2161 	/* Exit if there aren't any parent levels to update. */
2162 	if (level + 1 >= cur->bc_nlevels)
2163 		return 0;
2164 
2165 	trace_xfs_btree_updkeys(cur, level, bp0);
2166 
2167 	lkey = &key;
2168 	hkey = xfs_btree_high_key_from_key(cur, lkey);
2169 	xfs_btree_get_keys(cur, block, lkey);
2170 	for (level++; level < cur->bc_nlevels; level++) {
2171 #ifdef DEBUG
2172 		int		error;
2173 #endif
2174 		block = xfs_btree_get_block(cur, level, &bp);
2175 		trace_xfs_btree_updkeys(cur, level, bp);
2176 #ifdef DEBUG
2177 		error = xfs_btree_check_block(cur, block, level, bp);
2178 		if (error)
2179 			return error;
2180 #endif
2181 		ptr = cur->bc_levels[level].ptr;
2182 		nlkey = xfs_btree_key_addr(cur, ptr, block);
2183 		nhkey = xfs_btree_high_key_addr(cur, ptr, block);
2184 		if (!force_all &&
2185 		    xfs_btree_keycmp_eq(cur, nlkey, lkey) &&
2186 		    xfs_btree_keycmp_eq(cur, nhkey, hkey))
2187 			break;
2188 		xfs_btree_copy_keys(cur, nlkey, lkey, 1);
2189 		xfs_btree_log_keys(cur, bp, ptr, ptr);
2190 		if (level + 1 >= cur->bc_nlevels)
2191 			break;
2192 		xfs_btree_get_node_keys(cur, block, lkey);
2193 	}
2194 
2195 	return 0;
2196 }
2197 
2198 /* Update all the keys from some level in cursor back to the root. */
2199 STATIC int
xfs_btree_updkeys_force(struct xfs_btree_cur * cur,int level)2200 xfs_btree_updkeys_force(
2201 	struct xfs_btree_cur	*cur,
2202 	int			level)
2203 {
2204 	struct xfs_buf		*bp;
2205 	struct xfs_btree_block	*block;
2206 
2207 	block = xfs_btree_get_block(cur, level, &bp);
2208 	return __xfs_btree_updkeys(cur, level, block, bp, true);
2209 }
2210 
2211 /*
2212  * Update the parent keys of the given level, progressing towards the root.
2213  */
2214 STATIC int
xfs_btree_update_keys(struct xfs_btree_cur * cur,int level)2215 xfs_btree_update_keys(
2216 	struct xfs_btree_cur	*cur,
2217 	int			level)
2218 {
2219 	struct xfs_btree_block	*block;
2220 	struct xfs_buf		*bp;
2221 	union xfs_btree_key	*kp;
2222 	union xfs_btree_key	key;
2223 	int			ptr;
2224 
2225 	ASSERT(level >= 0);
2226 
2227 	block = xfs_btree_get_block(cur, level, &bp);
2228 	if (cur->bc_flags & XFS_BTREE_OVERLAPPING)
2229 		return __xfs_btree_updkeys(cur, level, block, bp, false);
2230 
2231 	/*
2232 	 * Go up the tree from this level toward the root.
2233 	 * At each level, update the key value to the value input.
2234 	 * Stop when we reach a level where the cursor isn't pointing
2235 	 * at the first entry in the block.
2236 	 */
2237 	xfs_btree_get_keys(cur, block, &key);
2238 	for (level++, ptr = 1; ptr == 1 && level < cur->bc_nlevels; level++) {
2239 #ifdef DEBUG
2240 		int		error;
2241 #endif
2242 		block = xfs_btree_get_block(cur, level, &bp);
2243 #ifdef DEBUG
2244 		error = xfs_btree_check_block(cur, block, level, bp);
2245 		if (error)
2246 			return error;
2247 #endif
2248 		ptr = cur->bc_levels[level].ptr;
2249 		kp = xfs_btree_key_addr(cur, ptr, block);
2250 		xfs_btree_copy_keys(cur, kp, &key, 1);
2251 		xfs_btree_log_keys(cur, bp, ptr, ptr);
2252 	}
2253 
2254 	return 0;
2255 }
2256 
2257 /*
2258  * Update the record referred to by cur to the value in the
2259  * given record. This either works (return 0) or gets an
2260  * EFSCORRUPTED error.
2261  */
2262 int
xfs_btree_update(struct xfs_btree_cur * cur,union xfs_btree_rec * rec)2263 xfs_btree_update(
2264 	struct xfs_btree_cur	*cur,
2265 	union xfs_btree_rec	*rec)
2266 {
2267 	struct xfs_btree_block	*block;
2268 	struct xfs_buf		*bp;
2269 	int			error;
2270 	int			ptr;
2271 	union xfs_btree_rec	*rp;
2272 
2273 	/* Pick up the current block. */
2274 	block = xfs_btree_get_block(cur, 0, &bp);
2275 
2276 #ifdef DEBUG
2277 	error = xfs_btree_check_block(cur, block, 0, bp);
2278 	if (error)
2279 		goto error0;
2280 #endif
2281 	/* Get the address of the rec to be updated. */
2282 	ptr = cur->bc_levels[0].ptr;
2283 	rp = xfs_btree_rec_addr(cur, ptr, block);
2284 
2285 	/* Fill in the new contents and log them. */
2286 	xfs_btree_copy_recs(cur, rp, rec, 1);
2287 	xfs_btree_log_recs(cur, bp, ptr, ptr);
2288 
2289 	/*
2290 	 * If we are tracking the last record in the tree and
2291 	 * we are at the far right edge of the tree, update it.
2292 	 */
2293 	if (xfs_btree_is_lastrec(cur, block, 0)) {
2294 		cur->bc_ops->update_lastrec(cur, block, rec,
2295 					    ptr, LASTREC_UPDATE);
2296 	}
2297 
2298 	/* Pass new key value up to our parent. */
2299 	if (xfs_btree_needs_key_update(cur, ptr)) {
2300 		error = xfs_btree_update_keys(cur, 0);
2301 		if (error)
2302 			goto error0;
2303 	}
2304 
2305 	return 0;
2306 
2307 error0:
2308 	return error;
2309 }
2310 
2311 /*
2312  * Move 1 record left from cur/level if possible.
2313  * Update cur to reflect the new path.
2314  */
2315 STATIC int					/* error */
xfs_btree_lshift(struct xfs_btree_cur * cur,int level,int * stat)2316 xfs_btree_lshift(
2317 	struct xfs_btree_cur	*cur,
2318 	int			level,
2319 	int			*stat)		/* success/failure */
2320 {
2321 	struct xfs_buf		*lbp;		/* left buffer pointer */
2322 	struct xfs_btree_block	*left;		/* left btree block */
2323 	int			lrecs;		/* left record count */
2324 	struct xfs_buf		*rbp;		/* right buffer pointer */
2325 	struct xfs_btree_block	*right;		/* right btree block */
2326 	struct xfs_btree_cur	*tcur;		/* temporary btree cursor */
2327 	int			rrecs;		/* right record count */
2328 	union xfs_btree_ptr	lptr;		/* left btree pointer */
2329 	union xfs_btree_key	*rkp = NULL;	/* right btree key */
2330 	union xfs_btree_ptr	*rpp = NULL;	/* right address pointer */
2331 	union xfs_btree_rec	*rrp = NULL;	/* right record pointer */
2332 	int			error;		/* error return value */
2333 	int			i;
2334 
2335 	if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
2336 	    level == cur->bc_nlevels - 1)
2337 		goto out0;
2338 
2339 	/* Set up variables for this block as "right". */
2340 	right = xfs_btree_get_block(cur, level, &rbp);
2341 
2342 #ifdef DEBUG
2343 	error = xfs_btree_check_block(cur, right, level, rbp);
2344 	if (error)
2345 		goto error0;
2346 #endif
2347 
2348 	/* If we've got no left sibling then we can't shift an entry left. */
2349 	xfs_btree_get_sibling(cur, right, &lptr, XFS_BB_LEFTSIB);
2350 	if (xfs_btree_ptr_is_null(cur, &lptr))
2351 		goto out0;
2352 
2353 	/*
2354 	 * If the cursor entry is the one that would be moved, don't
2355 	 * do it... it's too complicated.
2356 	 */
2357 	if (cur->bc_levels[level].ptr <= 1)
2358 		goto out0;
2359 
2360 	/* Set up the left neighbor as "left". */
2361 	error = xfs_btree_read_buf_block(cur, &lptr, 0, &left, &lbp);
2362 	if (error)
2363 		goto error0;
2364 
2365 	/* If it's full, it can't take another entry. */
2366 	lrecs = xfs_btree_get_numrecs(left);
2367 	if (lrecs == cur->bc_ops->get_maxrecs(cur, level))
2368 		goto out0;
2369 
2370 	rrecs = xfs_btree_get_numrecs(right);
2371 
2372 	/*
2373 	 * We add one entry to the left side and remove one for the right side.
2374 	 * Account for it here, the changes will be updated on disk and logged
2375 	 * later.
2376 	 */
2377 	lrecs++;
2378 	rrecs--;
2379 
2380 	XFS_BTREE_STATS_INC(cur, lshift);
2381 	XFS_BTREE_STATS_ADD(cur, moves, 1);
2382 
2383 	/*
2384 	 * If non-leaf, copy a key and a ptr to the left block.
2385 	 * Log the changes to the left block.
2386 	 */
2387 	if (level > 0) {
2388 		/* It's a non-leaf.  Move keys and pointers. */
2389 		union xfs_btree_key	*lkp;	/* left btree key */
2390 		union xfs_btree_ptr	*lpp;	/* left address pointer */
2391 
2392 		lkp = xfs_btree_key_addr(cur, lrecs, left);
2393 		rkp = xfs_btree_key_addr(cur, 1, right);
2394 
2395 		lpp = xfs_btree_ptr_addr(cur, lrecs, left);
2396 		rpp = xfs_btree_ptr_addr(cur, 1, right);
2397 
2398 		error = xfs_btree_debug_check_ptr(cur, rpp, 0, level);
2399 		if (error)
2400 			goto error0;
2401 
2402 		xfs_btree_copy_keys(cur, lkp, rkp, 1);
2403 		xfs_btree_copy_ptrs(cur, lpp, rpp, 1);
2404 
2405 		xfs_btree_log_keys(cur, lbp, lrecs, lrecs);
2406 		xfs_btree_log_ptrs(cur, lbp, lrecs, lrecs);
2407 
2408 		ASSERT(cur->bc_ops->keys_inorder(cur,
2409 			xfs_btree_key_addr(cur, lrecs - 1, left), lkp));
2410 	} else {
2411 		/* It's a leaf.  Move records.  */
2412 		union xfs_btree_rec	*lrp;	/* left record pointer */
2413 
2414 		lrp = xfs_btree_rec_addr(cur, lrecs, left);
2415 		rrp = xfs_btree_rec_addr(cur, 1, right);
2416 
2417 		xfs_btree_copy_recs(cur, lrp, rrp, 1);
2418 		xfs_btree_log_recs(cur, lbp, lrecs, lrecs);
2419 
2420 		ASSERT(cur->bc_ops->recs_inorder(cur,
2421 			xfs_btree_rec_addr(cur, lrecs - 1, left), lrp));
2422 	}
2423 
2424 	xfs_btree_set_numrecs(left, lrecs);
2425 	xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS);
2426 
2427 	xfs_btree_set_numrecs(right, rrecs);
2428 	xfs_btree_log_block(cur, rbp, XFS_BB_NUMRECS);
2429 
2430 	/*
2431 	 * Slide the contents of right down one entry.
2432 	 */
2433 	XFS_BTREE_STATS_ADD(cur, moves, rrecs - 1);
2434 	if (level > 0) {
2435 		/* It's a nonleaf. operate on keys and ptrs */
2436 		for (i = 0; i < rrecs; i++) {
2437 			error = xfs_btree_debug_check_ptr(cur, rpp, i + 1, level);
2438 			if (error)
2439 				goto error0;
2440 		}
2441 
2442 		xfs_btree_shift_keys(cur,
2443 				xfs_btree_key_addr(cur, 2, right),
2444 				-1, rrecs);
2445 		xfs_btree_shift_ptrs(cur,
2446 				xfs_btree_ptr_addr(cur, 2, right),
2447 				-1, rrecs);
2448 
2449 		xfs_btree_log_keys(cur, rbp, 1, rrecs);
2450 		xfs_btree_log_ptrs(cur, rbp, 1, rrecs);
2451 	} else {
2452 		/* It's a leaf. operate on records */
2453 		xfs_btree_shift_recs(cur,
2454 			xfs_btree_rec_addr(cur, 2, right),
2455 			-1, rrecs);
2456 		xfs_btree_log_recs(cur, rbp, 1, rrecs);
2457 	}
2458 
2459 	/*
2460 	 * Using a temporary cursor, update the parent key values of the
2461 	 * block on the left.
2462 	 */
2463 	if (cur->bc_flags & XFS_BTREE_OVERLAPPING) {
2464 		error = xfs_btree_dup_cursor(cur, &tcur);
2465 		if (error)
2466 			goto error0;
2467 		i = xfs_btree_firstrec(tcur, level);
2468 		if (XFS_IS_CORRUPT(tcur->bc_mp, i != 1)) {
2469 			error = -EFSCORRUPTED;
2470 			goto error0;
2471 		}
2472 
2473 		error = xfs_btree_decrement(tcur, level, &i);
2474 		if (error)
2475 			goto error1;
2476 
2477 		/* Update the parent high keys of the left block, if needed. */
2478 		error = xfs_btree_update_keys(tcur, level);
2479 		if (error)
2480 			goto error1;
2481 
2482 		xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
2483 	}
2484 
2485 	/* Update the parent keys of the right block. */
2486 	error = xfs_btree_update_keys(cur, level);
2487 	if (error)
2488 		goto error0;
2489 
2490 	/* Slide the cursor value left one. */
2491 	cur->bc_levels[level].ptr--;
2492 
2493 	*stat = 1;
2494 	return 0;
2495 
2496 out0:
2497 	*stat = 0;
2498 	return 0;
2499 
2500 error0:
2501 	return error;
2502 
2503 error1:
2504 	xfs_btree_del_cursor(tcur, XFS_BTREE_ERROR);
2505 	return error;
2506 }
2507 
2508 /*
2509  * Move 1 record right from cur/level if possible.
2510  * Update cur to reflect the new path.
2511  */
2512 STATIC int					/* error */
xfs_btree_rshift(struct xfs_btree_cur * cur,int level,int * stat)2513 xfs_btree_rshift(
2514 	struct xfs_btree_cur	*cur,
2515 	int			level,
2516 	int			*stat)		/* success/failure */
2517 {
2518 	struct xfs_buf		*lbp;		/* left buffer pointer */
2519 	struct xfs_btree_block	*left;		/* left btree block */
2520 	struct xfs_buf		*rbp;		/* right buffer pointer */
2521 	struct xfs_btree_block	*right;		/* right btree block */
2522 	struct xfs_btree_cur	*tcur;		/* temporary btree cursor */
2523 	union xfs_btree_ptr	rptr;		/* right block pointer */
2524 	union xfs_btree_key	*rkp;		/* right btree key */
2525 	int			rrecs;		/* right record count */
2526 	int			lrecs;		/* left record count */
2527 	int			error;		/* error return value */
2528 	int			i;		/* loop counter */
2529 
2530 	if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
2531 	    (level == cur->bc_nlevels - 1))
2532 		goto out0;
2533 
2534 	/* Set up variables for this block as "left". */
2535 	left = xfs_btree_get_block(cur, level, &lbp);
2536 
2537 #ifdef DEBUG
2538 	error = xfs_btree_check_block(cur, left, level, lbp);
2539 	if (error)
2540 		goto error0;
2541 #endif
2542 
2543 	/* If we've got no right sibling then we can't shift an entry right. */
2544 	xfs_btree_get_sibling(cur, left, &rptr, XFS_BB_RIGHTSIB);
2545 	if (xfs_btree_ptr_is_null(cur, &rptr))
2546 		goto out0;
2547 
2548 	/*
2549 	 * If the cursor entry is the one that would be moved, don't
2550 	 * do it... it's too complicated.
2551 	 */
2552 	lrecs = xfs_btree_get_numrecs(left);
2553 	if (cur->bc_levels[level].ptr >= lrecs)
2554 		goto out0;
2555 
2556 	/* Set up the right neighbor as "right". */
2557 	error = xfs_btree_read_buf_block(cur, &rptr, 0, &right, &rbp);
2558 	if (error)
2559 		goto error0;
2560 
2561 	/* If it's full, it can't take another entry. */
2562 	rrecs = xfs_btree_get_numrecs(right);
2563 	if (rrecs == cur->bc_ops->get_maxrecs(cur, level))
2564 		goto out0;
2565 
2566 	XFS_BTREE_STATS_INC(cur, rshift);
2567 	XFS_BTREE_STATS_ADD(cur, moves, rrecs);
2568 
2569 	/*
2570 	 * Make a hole at the start of the right neighbor block, then
2571 	 * copy the last left block entry to the hole.
2572 	 */
2573 	if (level > 0) {
2574 		/* It's a nonleaf. make a hole in the keys and ptrs */
2575 		union xfs_btree_key	*lkp;
2576 		union xfs_btree_ptr	*lpp;
2577 		union xfs_btree_ptr	*rpp;
2578 
2579 		lkp = xfs_btree_key_addr(cur, lrecs, left);
2580 		lpp = xfs_btree_ptr_addr(cur, lrecs, left);
2581 		rkp = xfs_btree_key_addr(cur, 1, right);
2582 		rpp = xfs_btree_ptr_addr(cur, 1, right);
2583 
2584 		for (i = rrecs - 1; i >= 0; i--) {
2585 			error = xfs_btree_debug_check_ptr(cur, rpp, i, level);
2586 			if (error)
2587 				goto error0;
2588 		}
2589 
2590 		xfs_btree_shift_keys(cur, rkp, 1, rrecs);
2591 		xfs_btree_shift_ptrs(cur, rpp, 1, rrecs);
2592 
2593 		error = xfs_btree_debug_check_ptr(cur, lpp, 0, level);
2594 		if (error)
2595 			goto error0;
2596 
2597 		/* Now put the new data in, and log it. */
2598 		xfs_btree_copy_keys(cur, rkp, lkp, 1);
2599 		xfs_btree_copy_ptrs(cur, rpp, lpp, 1);
2600 
2601 		xfs_btree_log_keys(cur, rbp, 1, rrecs + 1);
2602 		xfs_btree_log_ptrs(cur, rbp, 1, rrecs + 1);
2603 
2604 		ASSERT(cur->bc_ops->keys_inorder(cur, rkp,
2605 			xfs_btree_key_addr(cur, 2, right)));
2606 	} else {
2607 		/* It's a leaf. make a hole in the records */
2608 		union xfs_btree_rec	*lrp;
2609 		union xfs_btree_rec	*rrp;
2610 
2611 		lrp = xfs_btree_rec_addr(cur, lrecs, left);
2612 		rrp = xfs_btree_rec_addr(cur, 1, right);
2613 
2614 		xfs_btree_shift_recs(cur, rrp, 1, rrecs);
2615 
2616 		/* Now put the new data in, and log it. */
2617 		xfs_btree_copy_recs(cur, rrp, lrp, 1);
2618 		xfs_btree_log_recs(cur, rbp, 1, rrecs + 1);
2619 	}
2620 
2621 	/*
2622 	 * Decrement and log left's numrecs, bump and log right's numrecs.
2623 	 */
2624 	xfs_btree_set_numrecs(left, --lrecs);
2625 	xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS);
2626 
2627 	xfs_btree_set_numrecs(right, ++rrecs);
2628 	xfs_btree_log_block(cur, rbp, XFS_BB_NUMRECS);
2629 
2630 	/*
2631 	 * Using a temporary cursor, update the parent key values of the
2632 	 * block on the right.
2633 	 */
2634 	error = xfs_btree_dup_cursor(cur, &tcur);
2635 	if (error)
2636 		goto error0;
2637 	i = xfs_btree_lastrec(tcur, level);
2638 	if (XFS_IS_CORRUPT(tcur->bc_mp, i != 1)) {
2639 		error = -EFSCORRUPTED;
2640 		goto error0;
2641 	}
2642 
2643 	error = xfs_btree_increment(tcur, level, &i);
2644 	if (error)
2645 		goto error1;
2646 
2647 	/* Update the parent high keys of the left block, if needed. */
2648 	if (cur->bc_flags & XFS_BTREE_OVERLAPPING) {
2649 		error = xfs_btree_update_keys(cur, level);
2650 		if (error)
2651 			goto error1;
2652 	}
2653 
2654 	/* Update the parent keys of the right block. */
2655 	error = xfs_btree_update_keys(tcur, level);
2656 	if (error)
2657 		goto error1;
2658 
2659 	xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
2660 
2661 	*stat = 1;
2662 	return 0;
2663 
2664 out0:
2665 	*stat = 0;
2666 	return 0;
2667 
2668 error0:
2669 	return error;
2670 
2671 error1:
2672 	xfs_btree_del_cursor(tcur, XFS_BTREE_ERROR);
2673 	return error;
2674 }
2675 
2676 /*
2677  * Split cur/level block in half.
2678  * Return new block number and the key to its first
2679  * record (to be inserted into parent).
2680  */
2681 STATIC int					/* error */
__xfs_btree_split(struct xfs_btree_cur * cur,int level,union xfs_btree_ptr * ptrp,union xfs_btree_key * key,struct xfs_btree_cur ** curp,int * stat)2682 __xfs_btree_split(
2683 	struct xfs_btree_cur	*cur,
2684 	int			level,
2685 	union xfs_btree_ptr	*ptrp,
2686 	union xfs_btree_key	*key,
2687 	struct xfs_btree_cur	**curp,
2688 	int			*stat)		/* success/failure */
2689 {
2690 	union xfs_btree_ptr	lptr;		/* left sibling block ptr */
2691 	struct xfs_buf		*lbp;		/* left buffer pointer */
2692 	struct xfs_btree_block	*left;		/* left btree block */
2693 	union xfs_btree_ptr	rptr;		/* right sibling block ptr */
2694 	struct xfs_buf		*rbp;		/* right buffer pointer */
2695 	struct xfs_btree_block	*right;		/* right btree block */
2696 	union xfs_btree_ptr	rrptr;		/* right-right sibling ptr */
2697 	struct xfs_buf		*rrbp;		/* right-right buffer pointer */
2698 	struct xfs_btree_block	*rrblock;	/* right-right btree block */
2699 	int			lrecs;
2700 	int			rrecs;
2701 	int			src_index;
2702 	int			error;		/* error return value */
2703 	int			i;
2704 
2705 	XFS_BTREE_STATS_INC(cur, split);
2706 
2707 	/* Set up left block (current one). */
2708 	left = xfs_btree_get_block(cur, level, &lbp);
2709 
2710 #ifdef DEBUG
2711 	error = xfs_btree_check_block(cur, left, level, lbp);
2712 	if (error)
2713 		goto error0;
2714 #endif
2715 
2716 	xfs_btree_buf_to_ptr(cur, lbp, &lptr);
2717 
2718 	/* Allocate the new block. If we can't do it, we're toast. Give up. */
2719 	error = cur->bc_ops->alloc_block(cur, &lptr, &rptr, stat);
2720 	if (error)
2721 		goto error0;
2722 	if (*stat == 0)
2723 		goto out0;
2724 	XFS_BTREE_STATS_INC(cur, alloc);
2725 
2726 	/* Set up the new block as "right". */
2727 	error = xfs_btree_get_buf_block(cur, &rptr, &right, &rbp);
2728 	if (error)
2729 		goto error0;
2730 
2731 	/* Fill in the btree header for the new right block. */
2732 	xfs_btree_init_block_cur(cur, rbp, xfs_btree_get_level(left), 0);
2733 
2734 	/*
2735 	 * Split the entries between the old and the new block evenly.
2736 	 * Make sure that if there's an odd number of entries now, that
2737 	 * each new block will have the same number of entries.
2738 	 */
2739 	lrecs = xfs_btree_get_numrecs(left);
2740 	rrecs = lrecs / 2;
2741 	if ((lrecs & 1) && cur->bc_levels[level].ptr <= rrecs + 1)
2742 		rrecs++;
2743 	src_index = (lrecs - rrecs + 1);
2744 
2745 	XFS_BTREE_STATS_ADD(cur, moves, rrecs);
2746 
2747 	/* Adjust numrecs for the later get_*_keys() calls. */
2748 	lrecs -= rrecs;
2749 	xfs_btree_set_numrecs(left, lrecs);
2750 	xfs_btree_set_numrecs(right, xfs_btree_get_numrecs(right) + rrecs);
2751 
2752 	/*
2753 	 * Copy btree block entries from the left block over to the
2754 	 * new block, the right. Update the right block and log the
2755 	 * changes.
2756 	 */
2757 	if (level > 0) {
2758 		/* It's a non-leaf.  Move keys and pointers. */
2759 		union xfs_btree_key	*lkp;	/* left btree key */
2760 		union xfs_btree_ptr	*lpp;	/* left address pointer */
2761 		union xfs_btree_key	*rkp;	/* right btree key */
2762 		union xfs_btree_ptr	*rpp;	/* right address pointer */
2763 
2764 		lkp = xfs_btree_key_addr(cur, src_index, left);
2765 		lpp = xfs_btree_ptr_addr(cur, src_index, left);
2766 		rkp = xfs_btree_key_addr(cur, 1, right);
2767 		rpp = xfs_btree_ptr_addr(cur, 1, right);
2768 
2769 		for (i = src_index; i < rrecs; i++) {
2770 			error = xfs_btree_debug_check_ptr(cur, lpp, i, level);
2771 			if (error)
2772 				goto error0;
2773 		}
2774 
2775 		/* Copy the keys & pointers to the new block. */
2776 		xfs_btree_copy_keys(cur, rkp, lkp, rrecs);
2777 		xfs_btree_copy_ptrs(cur, rpp, lpp, rrecs);
2778 
2779 		xfs_btree_log_keys(cur, rbp, 1, rrecs);
2780 		xfs_btree_log_ptrs(cur, rbp, 1, rrecs);
2781 
2782 		/* Stash the keys of the new block for later insertion. */
2783 		xfs_btree_get_node_keys(cur, right, key);
2784 	} else {
2785 		/* It's a leaf.  Move records.  */
2786 		union xfs_btree_rec	*lrp;	/* left record pointer */
2787 		union xfs_btree_rec	*rrp;	/* right record pointer */
2788 
2789 		lrp = xfs_btree_rec_addr(cur, src_index, left);
2790 		rrp = xfs_btree_rec_addr(cur, 1, right);
2791 
2792 		/* Copy records to the new block. */
2793 		xfs_btree_copy_recs(cur, rrp, lrp, rrecs);
2794 		xfs_btree_log_recs(cur, rbp, 1, rrecs);
2795 
2796 		/* Stash the keys of the new block for later insertion. */
2797 		xfs_btree_get_leaf_keys(cur, right, key);
2798 	}
2799 
2800 	/*
2801 	 * Find the left block number by looking in the buffer.
2802 	 * Adjust sibling pointers.
2803 	 */
2804 	xfs_btree_get_sibling(cur, left, &rrptr, XFS_BB_RIGHTSIB);
2805 	xfs_btree_set_sibling(cur, right, &rrptr, XFS_BB_RIGHTSIB);
2806 	xfs_btree_set_sibling(cur, right, &lptr, XFS_BB_LEFTSIB);
2807 	xfs_btree_set_sibling(cur, left, &rptr, XFS_BB_RIGHTSIB);
2808 
2809 	xfs_btree_log_block(cur, rbp, XFS_BB_ALL_BITS);
2810 	xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS | XFS_BB_RIGHTSIB);
2811 
2812 	/*
2813 	 * If there's a block to the new block's right, make that block
2814 	 * point back to right instead of to left.
2815 	 */
2816 	if (!xfs_btree_ptr_is_null(cur, &rrptr)) {
2817 		error = xfs_btree_read_buf_block(cur, &rrptr,
2818 							0, &rrblock, &rrbp);
2819 		if (error)
2820 			goto error0;
2821 		xfs_btree_set_sibling(cur, rrblock, &rptr, XFS_BB_LEFTSIB);
2822 		xfs_btree_log_block(cur, rrbp, XFS_BB_LEFTSIB);
2823 	}
2824 
2825 	/* Update the parent high keys of the left block, if needed. */
2826 	if (cur->bc_flags & XFS_BTREE_OVERLAPPING) {
2827 		error = xfs_btree_update_keys(cur, level);
2828 		if (error)
2829 			goto error0;
2830 	}
2831 
2832 	/*
2833 	 * If the cursor is really in the right block, move it there.
2834 	 * If it's just pointing past the last entry in left, then we'll
2835 	 * insert there, so don't change anything in that case.
2836 	 */
2837 	if (cur->bc_levels[level].ptr > lrecs + 1) {
2838 		xfs_btree_setbuf(cur, level, rbp);
2839 		cur->bc_levels[level].ptr -= lrecs;
2840 	}
2841 	/*
2842 	 * If there are more levels, we'll need another cursor which refers
2843 	 * the right block, no matter where this cursor was.
2844 	 */
2845 	if (level + 1 < cur->bc_nlevels) {
2846 		error = xfs_btree_dup_cursor(cur, curp);
2847 		if (error)
2848 			goto error0;
2849 		(*curp)->bc_levels[level + 1].ptr++;
2850 	}
2851 	*ptrp = rptr;
2852 	*stat = 1;
2853 	return 0;
2854 out0:
2855 	*stat = 0;
2856 	return 0;
2857 
2858 error0:
2859 	return error;
2860 }
2861 
2862 #ifdef __KERNEL__
2863 struct xfs_btree_split_args {
2864 	struct xfs_btree_cur	*cur;
2865 	int			level;
2866 	union xfs_btree_ptr	*ptrp;
2867 	union xfs_btree_key	*key;
2868 	struct xfs_btree_cur	**curp;
2869 	int			*stat;		/* success/failure */
2870 	int			result;
2871 	bool			kswapd;	/* allocation in kswapd context */
2872 	struct completion	*done;
2873 	struct work_struct	work;
2874 };
2875 
2876 /*
2877  * Stack switching interfaces for allocation
2878  */
2879 static void
xfs_btree_split_worker(struct work_struct * work)2880 xfs_btree_split_worker(
2881 	struct work_struct	*work)
2882 {
2883 	struct xfs_btree_split_args	*args = container_of(work,
2884 						struct xfs_btree_split_args, work);
2885 	unsigned long		pflags;
2886 	unsigned long		new_pflags = 0;
2887 
2888 	/*
2889 	 * we are in a transaction context here, but may also be doing work
2890 	 * in kswapd context, and hence we may need to inherit that state
2891 	 * temporarily to ensure that we don't block waiting for memory reclaim
2892 	 * in any way.
2893 	 */
2894 	if (args->kswapd)
2895 		new_pflags |= PF_MEMALLOC | PF_KSWAPD;
2896 
2897 	current_set_flags_nested(&pflags, new_pflags);
2898 	xfs_trans_set_context(args->cur->bc_tp);
2899 
2900 	args->result = __xfs_btree_split(args->cur, args->level, args->ptrp,
2901 					 args->key, args->curp, args->stat);
2902 
2903 	xfs_trans_clear_context(args->cur->bc_tp);
2904 	current_restore_flags_nested(&pflags, new_pflags);
2905 
2906 	/*
2907 	 * Do not access args after complete() has run here. We don't own args
2908 	 * and the owner may run and free args before we return here.
2909 	 */
2910 	complete(args->done);
2911 
2912 }
2913 
2914 /*
2915  * BMBT split requests often come in with little stack to work on so we push
2916  * them off to a worker thread so there is lots of stack to use. For the other
2917  * btree types, just call directly to avoid the context switch overhead here.
2918  *
2919  * Care must be taken here - the work queue rescuer thread introduces potential
2920  * AGF <> worker queue deadlocks if the BMBT block allocation has to lock new
2921  * AGFs to allocate blocks. A task being run by the rescuer could attempt to
2922  * lock an AGF that is already locked by a task queued to run by the rescuer,
2923  * resulting in an ABBA deadlock as the rescuer cannot run the lock holder to
2924  * release it until the current thread it is running gains the lock.
2925  *
2926  * To avoid this issue, we only ever queue BMBT splits that don't have an AGF
2927  * already locked to allocate from. The only place that doesn't hold an AGF
2928  * locked is unwritten extent conversion at IO completion, but that has already
2929  * been offloaded to a worker thread and hence has no stack consumption issues
2930  * we have to worry about.
2931  */
2932 STATIC int					/* error */
xfs_btree_split(struct xfs_btree_cur * cur,int level,union xfs_btree_ptr * ptrp,union xfs_btree_key * key,struct xfs_btree_cur ** curp,int * stat)2933 xfs_btree_split(
2934 	struct xfs_btree_cur	*cur,
2935 	int			level,
2936 	union xfs_btree_ptr	*ptrp,
2937 	union xfs_btree_key	*key,
2938 	struct xfs_btree_cur	**curp,
2939 	int			*stat)		/* success/failure */
2940 {
2941 	struct xfs_btree_split_args	args;
2942 	DECLARE_COMPLETION_ONSTACK(done);
2943 
2944 	if (cur->bc_btnum != XFS_BTNUM_BMAP ||
2945 	    cur->bc_tp->t_highest_agno == NULLAGNUMBER)
2946 		return __xfs_btree_split(cur, level, ptrp, key, curp, stat);
2947 
2948 	args.cur = cur;
2949 	args.level = level;
2950 	args.ptrp = ptrp;
2951 	args.key = key;
2952 	args.curp = curp;
2953 	args.stat = stat;
2954 	args.done = &done;
2955 	args.kswapd = current_is_kswapd();
2956 	INIT_WORK_ONSTACK(&args.work, xfs_btree_split_worker);
2957 	queue_work(xfs_alloc_wq, &args.work);
2958 	wait_for_completion(&done);
2959 	destroy_work_on_stack(&args.work);
2960 	return args.result;
2961 }
2962 #else
2963 #define xfs_btree_split	__xfs_btree_split
2964 #endif /* __KERNEL__ */
2965 
2966 
2967 /*
2968  * Copy the old inode root contents into a real block and make the
2969  * broot point to it.
2970  */
2971 int						/* error */
xfs_btree_new_iroot(struct xfs_btree_cur * cur,int * logflags,int * stat)2972 xfs_btree_new_iroot(
2973 	struct xfs_btree_cur	*cur,		/* btree cursor */
2974 	int			*logflags,	/* logging flags for inode */
2975 	int			*stat)		/* return status - 0 fail */
2976 {
2977 	struct xfs_buf		*cbp;		/* buffer for cblock */
2978 	struct xfs_btree_block	*block;		/* btree block */
2979 	struct xfs_btree_block	*cblock;	/* child btree block */
2980 	union xfs_btree_key	*ckp;		/* child key pointer */
2981 	union xfs_btree_ptr	*cpp;		/* child ptr pointer */
2982 	union xfs_btree_key	*kp;		/* pointer to btree key */
2983 	union xfs_btree_ptr	*pp;		/* pointer to block addr */
2984 	union xfs_btree_ptr	nptr;		/* new block addr */
2985 	int			level;		/* btree level */
2986 	int			error;		/* error return code */
2987 	int			i;		/* loop counter */
2988 
2989 	XFS_BTREE_STATS_INC(cur, newroot);
2990 
2991 	ASSERT(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE);
2992 
2993 	level = cur->bc_nlevels - 1;
2994 
2995 	block = xfs_btree_get_iroot(cur);
2996 	pp = xfs_btree_ptr_addr(cur, 1, block);
2997 
2998 	/* Allocate the new block. If we can't do it, we're toast. Give up. */
2999 	error = cur->bc_ops->alloc_block(cur, pp, &nptr, stat);
3000 	if (error)
3001 		goto error0;
3002 	if (*stat == 0)
3003 		return 0;
3004 
3005 	XFS_BTREE_STATS_INC(cur, alloc);
3006 
3007 	/* Copy the root into a real block. */
3008 	error = xfs_btree_get_buf_block(cur, &nptr, &cblock, &cbp);
3009 	if (error)
3010 		goto error0;
3011 
3012 	/*
3013 	 * we can't just memcpy() the root in for CRC enabled btree blocks.
3014 	 * In that case have to also ensure the blkno remains correct
3015 	 */
3016 	memcpy(cblock, block, xfs_btree_block_len(cur));
3017 	if (cur->bc_flags & XFS_BTREE_CRC_BLOCKS) {
3018 		__be64 bno = cpu_to_be64(xfs_buf_daddr(cbp));
3019 		if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
3020 			cblock->bb_u.l.bb_blkno = bno;
3021 		else
3022 			cblock->bb_u.s.bb_blkno = bno;
3023 	}
3024 
3025 	be16_add_cpu(&block->bb_level, 1);
3026 	xfs_btree_set_numrecs(block, 1);
3027 	cur->bc_nlevels++;
3028 	ASSERT(cur->bc_nlevels <= cur->bc_maxlevels);
3029 	cur->bc_levels[level + 1].ptr = 1;
3030 
3031 	kp = xfs_btree_key_addr(cur, 1, block);
3032 	ckp = xfs_btree_key_addr(cur, 1, cblock);
3033 	xfs_btree_copy_keys(cur, ckp, kp, xfs_btree_get_numrecs(cblock));
3034 
3035 	cpp = xfs_btree_ptr_addr(cur, 1, cblock);
3036 	for (i = 0; i < be16_to_cpu(cblock->bb_numrecs); i++) {
3037 		error = xfs_btree_debug_check_ptr(cur, pp, i, level);
3038 		if (error)
3039 			goto error0;
3040 	}
3041 
3042 	xfs_btree_copy_ptrs(cur, cpp, pp, xfs_btree_get_numrecs(cblock));
3043 
3044 	error = xfs_btree_debug_check_ptr(cur, &nptr, 0, level);
3045 	if (error)
3046 		goto error0;
3047 
3048 	xfs_btree_copy_ptrs(cur, pp, &nptr, 1);
3049 
3050 	xfs_iroot_realloc(cur->bc_ino.ip,
3051 			  1 - xfs_btree_get_numrecs(cblock),
3052 			  cur->bc_ino.whichfork);
3053 
3054 	xfs_btree_setbuf(cur, level, cbp);
3055 
3056 	/*
3057 	 * Do all this logging at the end so that
3058 	 * the root is at the right level.
3059 	 */
3060 	xfs_btree_log_block(cur, cbp, XFS_BB_ALL_BITS);
3061 	xfs_btree_log_keys(cur, cbp, 1, be16_to_cpu(cblock->bb_numrecs));
3062 	xfs_btree_log_ptrs(cur, cbp, 1, be16_to_cpu(cblock->bb_numrecs));
3063 
3064 	*logflags |=
3065 		XFS_ILOG_CORE | xfs_ilog_fbroot(cur->bc_ino.whichfork);
3066 	*stat = 1;
3067 	return 0;
3068 error0:
3069 	return error;
3070 }
3071 
3072 /*
3073  * Allocate a new root block, fill it in.
3074  */
3075 STATIC int				/* error */
xfs_btree_new_root(struct xfs_btree_cur * cur,int * stat)3076 xfs_btree_new_root(
3077 	struct xfs_btree_cur	*cur,	/* btree cursor */
3078 	int			*stat)	/* success/failure */
3079 {
3080 	struct xfs_btree_block	*block;	/* one half of the old root block */
3081 	struct xfs_buf		*bp;	/* buffer containing block */
3082 	int			error;	/* error return value */
3083 	struct xfs_buf		*lbp;	/* left buffer pointer */
3084 	struct xfs_btree_block	*left;	/* left btree block */
3085 	struct xfs_buf		*nbp;	/* new (root) buffer */
3086 	struct xfs_btree_block	*new;	/* new (root) btree block */
3087 	int			nptr;	/* new value for key index, 1 or 2 */
3088 	struct xfs_buf		*rbp;	/* right buffer pointer */
3089 	struct xfs_btree_block	*right;	/* right btree block */
3090 	union xfs_btree_ptr	rptr;
3091 	union xfs_btree_ptr	lptr;
3092 
3093 	XFS_BTREE_STATS_INC(cur, newroot);
3094 
3095 	/* initialise our start point from the cursor */
3096 	cur->bc_ops->init_ptr_from_cur(cur, &rptr);
3097 
3098 	/* Allocate the new block. If we can't do it, we're toast. Give up. */
3099 	error = cur->bc_ops->alloc_block(cur, &rptr, &lptr, stat);
3100 	if (error)
3101 		goto error0;
3102 	if (*stat == 0)
3103 		goto out0;
3104 	XFS_BTREE_STATS_INC(cur, alloc);
3105 
3106 	/* Set up the new block. */
3107 	error = xfs_btree_get_buf_block(cur, &lptr, &new, &nbp);
3108 	if (error)
3109 		goto error0;
3110 
3111 	/* Set the root in the holding structure  increasing the level by 1. */
3112 	cur->bc_ops->set_root(cur, &lptr, 1);
3113 
3114 	/*
3115 	 * At the previous root level there are now two blocks: the old root,
3116 	 * and the new block generated when it was split.  We don't know which
3117 	 * one the cursor is pointing at, so we set up variables "left" and
3118 	 * "right" for each case.
3119 	 */
3120 	block = xfs_btree_get_block(cur, cur->bc_nlevels - 1, &bp);
3121 
3122 #ifdef DEBUG
3123 	error = xfs_btree_check_block(cur, block, cur->bc_nlevels - 1, bp);
3124 	if (error)
3125 		goto error0;
3126 #endif
3127 
3128 	xfs_btree_get_sibling(cur, block, &rptr, XFS_BB_RIGHTSIB);
3129 	if (!xfs_btree_ptr_is_null(cur, &rptr)) {
3130 		/* Our block is left, pick up the right block. */
3131 		lbp = bp;
3132 		xfs_btree_buf_to_ptr(cur, lbp, &lptr);
3133 		left = block;
3134 		error = xfs_btree_read_buf_block(cur, &rptr, 0, &right, &rbp);
3135 		if (error)
3136 			goto error0;
3137 		bp = rbp;
3138 		nptr = 1;
3139 	} else {
3140 		/* Our block is right, pick up the left block. */
3141 		rbp = bp;
3142 		xfs_btree_buf_to_ptr(cur, rbp, &rptr);
3143 		right = block;
3144 		xfs_btree_get_sibling(cur, right, &lptr, XFS_BB_LEFTSIB);
3145 		error = xfs_btree_read_buf_block(cur, &lptr, 0, &left, &lbp);
3146 		if (error)
3147 			goto error0;
3148 		bp = lbp;
3149 		nptr = 2;
3150 	}
3151 
3152 	/* Fill in the new block's btree header and log it. */
3153 	xfs_btree_init_block_cur(cur, nbp, cur->bc_nlevels, 2);
3154 	xfs_btree_log_block(cur, nbp, XFS_BB_ALL_BITS);
3155 	ASSERT(!xfs_btree_ptr_is_null(cur, &lptr) &&
3156 			!xfs_btree_ptr_is_null(cur, &rptr));
3157 
3158 	/* Fill in the key data in the new root. */
3159 	if (xfs_btree_get_level(left) > 0) {
3160 		/*
3161 		 * Get the keys for the left block's keys and put them directly
3162 		 * in the parent block.  Do the same for the right block.
3163 		 */
3164 		xfs_btree_get_node_keys(cur, left,
3165 				xfs_btree_key_addr(cur, 1, new));
3166 		xfs_btree_get_node_keys(cur, right,
3167 				xfs_btree_key_addr(cur, 2, new));
3168 	} else {
3169 		/*
3170 		 * Get the keys for the left block's records and put them
3171 		 * directly in the parent block.  Do the same for the right
3172 		 * block.
3173 		 */
3174 		xfs_btree_get_leaf_keys(cur, left,
3175 			xfs_btree_key_addr(cur, 1, new));
3176 		xfs_btree_get_leaf_keys(cur, right,
3177 			xfs_btree_key_addr(cur, 2, new));
3178 	}
3179 	xfs_btree_log_keys(cur, nbp, 1, 2);
3180 
3181 	/* Fill in the pointer data in the new root. */
3182 	xfs_btree_copy_ptrs(cur,
3183 		xfs_btree_ptr_addr(cur, 1, new), &lptr, 1);
3184 	xfs_btree_copy_ptrs(cur,
3185 		xfs_btree_ptr_addr(cur, 2, new), &rptr, 1);
3186 	xfs_btree_log_ptrs(cur, nbp, 1, 2);
3187 
3188 	/* Fix up the cursor. */
3189 	xfs_btree_setbuf(cur, cur->bc_nlevels, nbp);
3190 	cur->bc_levels[cur->bc_nlevels].ptr = nptr;
3191 	cur->bc_nlevels++;
3192 	ASSERT(cur->bc_nlevels <= cur->bc_maxlevels);
3193 	*stat = 1;
3194 	return 0;
3195 error0:
3196 	return error;
3197 out0:
3198 	*stat = 0;
3199 	return 0;
3200 }
3201 
3202 STATIC int
xfs_btree_make_block_unfull(struct xfs_btree_cur * cur,int level,int numrecs,int * oindex,int * index,union xfs_btree_ptr * nptr,struct xfs_btree_cur ** ncur,union xfs_btree_key * key,int * stat)3203 xfs_btree_make_block_unfull(
3204 	struct xfs_btree_cur	*cur,	/* btree cursor */
3205 	int			level,	/* btree level */
3206 	int			numrecs,/* # of recs in block */
3207 	int			*oindex,/* old tree index */
3208 	int			*index,	/* new tree index */
3209 	union xfs_btree_ptr	*nptr,	/* new btree ptr */
3210 	struct xfs_btree_cur	**ncur,	/* new btree cursor */
3211 	union xfs_btree_key	*key,	/* key of new block */
3212 	int			*stat)
3213 {
3214 	int			error = 0;
3215 
3216 	if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
3217 	    level == cur->bc_nlevels - 1) {
3218 		struct xfs_inode *ip = cur->bc_ino.ip;
3219 
3220 		if (numrecs < cur->bc_ops->get_dmaxrecs(cur, level)) {
3221 			/* A root block that can be made bigger. */
3222 			xfs_iroot_realloc(ip, 1, cur->bc_ino.whichfork);
3223 			*stat = 1;
3224 		} else {
3225 			/* A root block that needs replacing */
3226 			int	logflags = 0;
3227 
3228 			error = xfs_btree_new_iroot(cur, &logflags, stat);
3229 			if (error || *stat == 0)
3230 				return error;
3231 
3232 			xfs_trans_log_inode(cur->bc_tp, ip, logflags);
3233 		}
3234 
3235 		return 0;
3236 	}
3237 
3238 	/* First, try shifting an entry to the right neighbor. */
3239 	error = xfs_btree_rshift(cur, level, stat);
3240 	if (error || *stat)
3241 		return error;
3242 
3243 	/* Next, try shifting an entry to the left neighbor. */
3244 	error = xfs_btree_lshift(cur, level, stat);
3245 	if (error)
3246 		return error;
3247 
3248 	if (*stat) {
3249 		*oindex = *index = cur->bc_levels[level].ptr;
3250 		return 0;
3251 	}
3252 
3253 	/*
3254 	 * Next, try splitting the current block in half.
3255 	 *
3256 	 * If this works we have to re-set our variables because we
3257 	 * could be in a different block now.
3258 	 */
3259 	error = xfs_btree_split(cur, level, nptr, key, ncur, stat);
3260 	if (error || *stat == 0)
3261 		return error;
3262 
3263 
3264 	*index = cur->bc_levels[level].ptr;
3265 	return 0;
3266 }
3267 
3268 /*
3269  * Insert one record/level.  Return information to the caller
3270  * allowing the next level up to proceed if necessary.
3271  */
3272 STATIC int
xfs_btree_insrec(struct xfs_btree_cur * cur,int level,union xfs_btree_ptr * ptrp,union xfs_btree_rec * rec,union xfs_btree_key * key,struct xfs_btree_cur ** curp,int * stat)3273 xfs_btree_insrec(
3274 	struct xfs_btree_cur	*cur,	/* btree cursor */
3275 	int			level,	/* level to insert record at */
3276 	union xfs_btree_ptr	*ptrp,	/* i/o: block number inserted */
3277 	union xfs_btree_rec	*rec,	/* record to insert */
3278 	union xfs_btree_key	*key,	/* i/o: block key for ptrp */
3279 	struct xfs_btree_cur	**curp,	/* output: new cursor replacing cur */
3280 	int			*stat)	/* success/failure */
3281 {
3282 	struct xfs_btree_block	*block;	/* btree block */
3283 	struct xfs_buf		*bp;	/* buffer for block */
3284 	union xfs_btree_ptr	nptr;	/* new block ptr */
3285 	struct xfs_btree_cur	*ncur = NULL;	/* new btree cursor */
3286 	union xfs_btree_key	nkey;	/* new block key */
3287 	union xfs_btree_key	*lkey;
3288 	int			optr;	/* old key/record index */
3289 	int			ptr;	/* key/record index */
3290 	int			numrecs;/* number of records */
3291 	int			error;	/* error return value */
3292 	int			i;
3293 	xfs_daddr_t		old_bn;
3294 
3295 	ncur = NULL;
3296 	lkey = &nkey;
3297 
3298 	/*
3299 	 * If we have an external root pointer, and we've made it to the
3300 	 * root level, allocate a new root block and we're done.
3301 	 */
3302 	if (!(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
3303 	    (level >= cur->bc_nlevels)) {
3304 		error = xfs_btree_new_root(cur, stat);
3305 		xfs_btree_set_ptr_null(cur, ptrp);
3306 
3307 		return error;
3308 	}
3309 
3310 	/* If we're off the left edge, return failure. */
3311 	ptr = cur->bc_levels[level].ptr;
3312 	if (ptr == 0) {
3313 		*stat = 0;
3314 		return 0;
3315 	}
3316 
3317 	optr = ptr;
3318 
3319 	XFS_BTREE_STATS_INC(cur, insrec);
3320 
3321 	/* Get pointers to the btree buffer and block. */
3322 	block = xfs_btree_get_block(cur, level, &bp);
3323 	old_bn = bp ? xfs_buf_daddr(bp) : XFS_BUF_DADDR_NULL;
3324 	numrecs = xfs_btree_get_numrecs(block);
3325 
3326 #ifdef DEBUG
3327 	error = xfs_btree_check_block(cur, block, level, bp);
3328 	if (error)
3329 		goto error0;
3330 
3331 	/* Check that the new entry is being inserted in the right place. */
3332 	if (ptr <= numrecs) {
3333 		if (level == 0) {
3334 			ASSERT(cur->bc_ops->recs_inorder(cur, rec,
3335 				xfs_btree_rec_addr(cur, ptr, block)));
3336 		} else {
3337 			ASSERT(cur->bc_ops->keys_inorder(cur, key,
3338 				xfs_btree_key_addr(cur, ptr, block)));
3339 		}
3340 	}
3341 #endif
3342 
3343 	/*
3344 	 * If the block is full, we can't insert the new entry until we
3345 	 * make the block un-full.
3346 	 */
3347 	xfs_btree_set_ptr_null(cur, &nptr);
3348 	if (numrecs == cur->bc_ops->get_maxrecs(cur, level)) {
3349 		error = xfs_btree_make_block_unfull(cur, level, numrecs,
3350 					&optr, &ptr, &nptr, &ncur, lkey, stat);
3351 		if (error || *stat == 0)
3352 			goto error0;
3353 	}
3354 
3355 	/*
3356 	 * The current block may have changed if the block was
3357 	 * previously full and we have just made space in it.
3358 	 */
3359 	block = xfs_btree_get_block(cur, level, &bp);
3360 	numrecs = xfs_btree_get_numrecs(block);
3361 
3362 #ifdef DEBUG
3363 	error = xfs_btree_check_block(cur, block, level, bp);
3364 	if (error)
3365 		goto error0;
3366 #endif
3367 
3368 	/*
3369 	 * At this point we know there's room for our new entry in the block
3370 	 * we're pointing at.
3371 	 */
3372 	XFS_BTREE_STATS_ADD(cur, moves, numrecs - ptr + 1);
3373 
3374 	if (level > 0) {
3375 		/* It's a nonleaf. make a hole in the keys and ptrs */
3376 		union xfs_btree_key	*kp;
3377 		union xfs_btree_ptr	*pp;
3378 
3379 		kp = xfs_btree_key_addr(cur, ptr, block);
3380 		pp = xfs_btree_ptr_addr(cur, ptr, block);
3381 
3382 		for (i = numrecs - ptr; i >= 0; i--) {
3383 			error = xfs_btree_debug_check_ptr(cur, pp, i, level);
3384 			if (error)
3385 				goto error0;
3386 		}
3387 
3388 		xfs_btree_shift_keys(cur, kp, 1, numrecs - ptr + 1);
3389 		xfs_btree_shift_ptrs(cur, pp, 1, numrecs - ptr + 1);
3390 
3391 		error = xfs_btree_debug_check_ptr(cur, ptrp, 0, level);
3392 		if (error)
3393 			goto error0;
3394 
3395 		/* Now put the new data in, bump numrecs and log it. */
3396 		xfs_btree_copy_keys(cur, kp, key, 1);
3397 		xfs_btree_copy_ptrs(cur, pp, ptrp, 1);
3398 		numrecs++;
3399 		xfs_btree_set_numrecs(block, numrecs);
3400 		xfs_btree_log_ptrs(cur, bp, ptr, numrecs);
3401 		xfs_btree_log_keys(cur, bp, ptr, numrecs);
3402 #ifdef DEBUG
3403 		if (ptr < numrecs) {
3404 			ASSERT(cur->bc_ops->keys_inorder(cur, kp,
3405 				xfs_btree_key_addr(cur, ptr + 1, block)));
3406 		}
3407 #endif
3408 	} else {
3409 		/* It's a leaf. make a hole in the records */
3410 		union xfs_btree_rec             *rp;
3411 
3412 		rp = xfs_btree_rec_addr(cur, ptr, block);
3413 
3414 		xfs_btree_shift_recs(cur, rp, 1, numrecs - ptr + 1);
3415 
3416 		/* Now put the new data in, bump numrecs and log it. */
3417 		xfs_btree_copy_recs(cur, rp, rec, 1);
3418 		xfs_btree_set_numrecs(block, ++numrecs);
3419 		xfs_btree_log_recs(cur, bp, ptr, numrecs);
3420 #ifdef DEBUG
3421 		if (ptr < numrecs) {
3422 			ASSERT(cur->bc_ops->recs_inorder(cur, rp,
3423 				xfs_btree_rec_addr(cur, ptr + 1, block)));
3424 		}
3425 #endif
3426 	}
3427 
3428 	/* Log the new number of records in the btree header. */
3429 	xfs_btree_log_block(cur, bp, XFS_BB_NUMRECS);
3430 
3431 	/*
3432 	 * If we just inserted into a new tree block, we have to
3433 	 * recalculate nkey here because nkey is out of date.
3434 	 *
3435 	 * Otherwise we're just updating an existing block (having shoved
3436 	 * some records into the new tree block), so use the regular key
3437 	 * update mechanism.
3438 	 */
3439 	if (bp && xfs_buf_daddr(bp) != old_bn) {
3440 		xfs_btree_get_keys(cur, block, lkey);
3441 	} else if (xfs_btree_needs_key_update(cur, optr)) {
3442 		error = xfs_btree_update_keys(cur, level);
3443 		if (error)
3444 			goto error0;
3445 	}
3446 
3447 	/*
3448 	 * If we are tracking the last record in the tree and
3449 	 * we are at the far right edge of the tree, update it.
3450 	 */
3451 	if (xfs_btree_is_lastrec(cur, block, level)) {
3452 		cur->bc_ops->update_lastrec(cur, block, rec,
3453 					    ptr, LASTREC_INSREC);
3454 	}
3455 
3456 	/*
3457 	 * Return the new block number, if any.
3458 	 * If there is one, give back a record value and a cursor too.
3459 	 */
3460 	*ptrp = nptr;
3461 	if (!xfs_btree_ptr_is_null(cur, &nptr)) {
3462 		xfs_btree_copy_keys(cur, key, lkey, 1);
3463 		*curp = ncur;
3464 	}
3465 
3466 	*stat = 1;
3467 	return 0;
3468 
3469 error0:
3470 	if (ncur)
3471 		xfs_btree_del_cursor(ncur, error);
3472 	return error;
3473 }
3474 
3475 /*
3476  * Insert the record at the point referenced by cur.
3477  *
3478  * A multi-level split of the tree on insert will invalidate the original
3479  * cursor.  All callers of this function should assume that the cursor is
3480  * no longer valid and revalidate it.
3481  */
3482 int
xfs_btree_insert(struct xfs_btree_cur * cur,int * stat)3483 xfs_btree_insert(
3484 	struct xfs_btree_cur	*cur,
3485 	int			*stat)
3486 {
3487 	int			error;	/* error return value */
3488 	int			i;	/* result value, 0 for failure */
3489 	int			level;	/* current level number in btree */
3490 	union xfs_btree_ptr	nptr;	/* new block number (split result) */
3491 	struct xfs_btree_cur	*ncur;	/* new cursor (split result) */
3492 	struct xfs_btree_cur	*pcur;	/* previous level's cursor */
3493 	union xfs_btree_key	bkey;	/* key of block to insert */
3494 	union xfs_btree_key	*key;
3495 	union xfs_btree_rec	rec;	/* record to insert */
3496 
3497 	level = 0;
3498 	ncur = NULL;
3499 	pcur = cur;
3500 	key = &bkey;
3501 
3502 	xfs_btree_set_ptr_null(cur, &nptr);
3503 
3504 	/* Make a key out of the record data to be inserted, and save it. */
3505 	cur->bc_ops->init_rec_from_cur(cur, &rec);
3506 	cur->bc_ops->init_key_from_rec(key, &rec);
3507 
3508 	/*
3509 	 * Loop going up the tree, starting at the leaf level.
3510 	 * Stop when we don't get a split block, that must mean that
3511 	 * the insert is finished with this level.
3512 	 */
3513 	do {
3514 		/*
3515 		 * Insert nrec/nptr into this level of the tree.
3516 		 * Note if we fail, nptr will be null.
3517 		 */
3518 		error = xfs_btree_insrec(pcur, level, &nptr, &rec, key,
3519 				&ncur, &i);
3520 		if (error) {
3521 			if (pcur != cur)
3522 				xfs_btree_del_cursor(pcur, XFS_BTREE_ERROR);
3523 			goto error0;
3524 		}
3525 
3526 		if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
3527 			error = -EFSCORRUPTED;
3528 			goto error0;
3529 		}
3530 		level++;
3531 
3532 		/*
3533 		 * See if the cursor we just used is trash.
3534 		 * Can't trash the caller's cursor, but otherwise we should
3535 		 * if ncur is a new cursor or we're about to be done.
3536 		 */
3537 		if (pcur != cur &&
3538 		    (ncur || xfs_btree_ptr_is_null(cur, &nptr))) {
3539 			/* Save the state from the cursor before we trash it */
3540 			if (cur->bc_ops->update_cursor)
3541 				cur->bc_ops->update_cursor(pcur, cur);
3542 			cur->bc_nlevels = pcur->bc_nlevels;
3543 			xfs_btree_del_cursor(pcur, XFS_BTREE_NOERROR);
3544 		}
3545 		/* If we got a new cursor, switch to it. */
3546 		if (ncur) {
3547 			pcur = ncur;
3548 			ncur = NULL;
3549 		}
3550 	} while (!xfs_btree_ptr_is_null(cur, &nptr));
3551 
3552 	*stat = i;
3553 	return 0;
3554 error0:
3555 	return error;
3556 }
3557 
3558 /*
3559  * Try to merge a non-leaf block back into the inode root.
3560  *
3561  * Note: the killroot names comes from the fact that we're effectively
3562  * killing the old root block.  But because we can't just delete the
3563  * inode we have to copy the single block it was pointing to into the
3564  * inode.
3565  */
3566 STATIC int
xfs_btree_kill_iroot(struct xfs_btree_cur * cur)3567 xfs_btree_kill_iroot(
3568 	struct xfs_btree_cur	*cur)
3569 {
3570 	int			whichfork = cur->bc_ino.whichfork;
3571 	struct xfs_inode	*ip = cur->bc_ino.ip;
3572 	struct xfs_ifork	*ifp = xfs_ifork_ptr(ip, whichfork);
3573 	struct xfs_btree_block	*block;
3574 	struct xfs_btree_block	*cblock;
3575 	union xfs_btree_key	*kp;
3576 	union xfs_btree_key	*ckp;
3577 	union xfs_btree_ptr	*pp;
3578 	union xfs_btree_ptr	*cpp;
3579 	struct xfs_buf		*cbp;
3580 	int			level;
3581 	int			index;
3582 	int			numrecs;
3583 	int			error;
3584 #ifdef DEBUG
3585 	union xfs_btree_ptr	ptr;
3586 #endif
3587 	int			i;
3588 
3589 	ASSERT(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE);
3590 	ASSERT(cur->bc_nlevels > 1);
3591 
3592 	/*
3593 	 * Don't deal with the root block needs to be a leaf case.
3594 	 * We're just going to turn the thing back into extents anyway.
3595 	 */
3596 	level = cur->bc_nlevels - 1;
3597 	if (level == 1)
3598 		goto out0;
3599 
3600 	/*
3601 	 * Give up if the root has multiple children.
3602 	 */
3603 	block = xfs_btree_get_iroot(cur);
3604 	if (xfs_btree_get_numrecs(block) != 1)
3605 		goto out0;
3606 
3607 	cblock = xfs_btree_get_block(cur, level - 1, &cbp);
3608 	numrecs = xfs_btree_get_numrecs(cblock);
3609 
3610 	/*
3611 	 * Only do this if the next level will fit.
3612 	 * Then the data must be copied up to the inode,
3613 	 * instead of freeing the root you free the next level.
3614 	 */
3615 	if (numrecs > cur->bc_ops->get_dmaxrecs(cur, level))
3616 		goto out0;
3617 
3618 	XFS_BTREE_STATS_INC(cur, killroot);
3619 
3620 #ifdef DEBUG
3621 	xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_LEFTSIB);
3622 	ASSERT(xfs_btree_ptr_is_null(cur, &ptr));
3623 	xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
3624 	ASSERT(xfs_btree_ptr_is_null(cur, &ptr));
3625 #endif
3626 
3627 	index = numrecs - cur->bc_ops->get_maxrecs(cur, level);
3628 	if (index) {
3629 		xfs_iroot_realloc(cur->bc_ino.ip, index,
3630 				  cur->bc_ino.whichfork);
3631 		block = ifp->if_broot;
3632 	}
3633 
3634 	be16_add_cpu(&block->bb_numrecs, index);
3635 	ASSERT(block->bb_numrecs == cblock->bb_numrecs);
3636 
3637 	kp = xfs_btree_key_addr(cur, 1, block);
3638 	ckp = xfs_btree_key_addr(cur, 1, cblock);
3639 	xfs_btree_copy_keys(cur, kp, ckp, numrecs);
3640 
3641 	pp = xfs_btree_ptr_addr(cur, 1, block);
3642 	cpp = xfs_btree_ptr_addr(cur, 1, cblock);
3643 
3644 	for (i = 0; i < numrecs; i++) {
3645 		error = xfs_btree_debug_check_ptr(cur, cpp, i, level - 1);
3646 		if (error)
3647 			return error;
3648 	}
3649 
3650 	xfs_btree_copy_ptrs(cur, pp, cpp, numrecs);
3651 
3652 	error = xfs_btree_free_block(cur, cbp);
3653 	if (error)
3654 		return error;
3655 
3656 	cur->bc_levels[level - 1].bp = NULL;
3657 	be16_add_cpu(&block->bb_level, -1);
3658 	xfs_trans_log_inode(cur->bc_tp, ip,
3659 		XFS_ILOG_CORE | xfs_ilog_fbroot(cur->bc_ino.whichfork));
3660 	cur->bc_nlevels--;
3661 out0:
3662 	return 0;
3663 }
3664 
3665 /*
3666  * Kill the current root node, and replace it with it's only child node.
3667  */
3668 STATIC int
xfs_btree_kill_root(struct xfs_btree_cur * cur,struct xfs_buf * bp,int level,union xfs_btree_ptr * newroot)3669 xfs_btree_kill_root(
3670 	struct xfs_btree_cur	*cur,
3671 	struct xfs_buf		*bp,
3672 	int			level,
3673 	union xfs_btree_ptr	*newroot)
3674 {
3675 	int			error;
3676 
3677 	XFS_BTREE_STATS_INC(cur, killroot);
3678 
3679 	/*
3680 	 * Update the root pointer, decreasing the level by 1 and then
3681 	 * free the old root.
3682 	 */
3683 	cur->bc_ops->set_root(cur, newroot, -1);
3684 
3685 	error = xfs_btree_free_block(cur, bp);
3686 	if (error)
3687 		return error;
3688 
3689 	cur->bc_levels[level].bp = NULL;
3690 	cur->bc_levels[level].ra = 0;
3691 	cur->bc_nlevels--;
3692 
3693 	return 0;
3694 }
3695 
3696 STATIC int
xfs_btree_dec_cursor(struct xfs_btree_cur * cur,int level,int * stat)3697 xfs_btree_dec_cursor(
3698 	struct xfs_btree_cur	*cur,
3699 	int			level,
3700 	int			*stat)
3701 {
3702 	int			error;
3703 	int			i;
3704 
3705 	if (level > 0) {
3706 		error = xfs_btree_decrement(cur, level, &i);
3707 		if (error)
3708 			return error;
3709 	}
3710 
3711 	*stat = 1;
3712 	return 0;
3713 }
3714 
3715 /*
3716  * Single level of the btree record deletion routine.
3717  * Delete record pointed to by cur/level.
3718  * Remove the record from its block then rebalance the tree.
3719  * Return 0 for error, 1 for done, 2 to go on to the next level.
3720  */
3721 STATIC int					/* error */
xfs_btree_delrec(struct xfs_btree_cur * cur,int level,int * stat)3722 xfs_btree_delrec(
3723 	struct xfs_btree_cur	*cur,		/* btree cursor */
3724 	int			level,		/* level removing record from */
3725 	int			*stat)		/* fail/done/go-on */
3726 {
3727 	struct xfs_btree_block	*block;		/* btree block */
3728 	union xfs_btree_ptr	cptr;		/* current block ptr */
3729 	struct xfs_buf		*bp;		/* buffer for block */
3730 	int			error;		/* error return value */
3731 	int			i;		/* loop counter */
3732 	union xfs_btree_ptr	lptr;		/* left sibling block ptr */
3733 	struct xfs_buf		*lbp;		/* left buffer pointer */
3734 	struct xfs_btree_block	*left;		/* left btree block */
3735 	int			lrecs = 0;	/* left record count */
3736 	int			ptr;		/* key/record index */
3737 	union xfs_btree_ptr	rptr;		/* right sibling block ptr */
3738 	struct xfs_buf		*rbp;		/* right buffer pointer */
3739 	struct xfs_btree_block	*right;		/* right btree block */
3740 	struct xfs_btree_block	*rrblock;	/* right-right btree block */
3741 	struct xfs_buf		*rrbp;		/* right-right buffer pointer */
3742 	int			rrecs = 0;	/* right record count */
3743 	struct xfs_btree_cur	*tcur;		/* temporary btree cursor */
3744 	int			numrecs;	/* temporary numrec count */
3745 
3746 	tcur = NULL;
3747 
3748 	/* Get the index of the entry being deleted, check for nothing there. */
3749 	ptr = cur->bc_levels[level].ptr;
3750 	if (ptr == 0) {
3751 		*stat = 0;
3752 		return 0;
3753 	}
3754 
3755 	/* Get the buffer & block containing the record or key/ptr. */
3756 	block = xfs_btree_get_block(cur, level, &bp);
3757 	numrecs = xfs_btree_get_numrecs(block);
3758 
3759 #ifdef DEBUG
3760 	error = xfs_btree_check_block(cur, block, level, bp);
3761 	if (error)
3762 		goto error0;
3763 #endif
3764 
3765 	/* Fail if we're off the end of the block. */
3766 	if (ptr > numrecs) {
3767 		*stat = 0;
3768 		return 0;
3769 	}
3770 
3771 	XFS_BTREE_STATS_INC(cur, delrec);
3772 	XFS_BTREE_STATS_ADD(cur, moves, numrecs - ptr);
3773 
3774 	/* Excise the entries being deleted. */
3775 	if (level > 0) {
3776 		/* It's a nonleaf. operate on keys and ptrs */
3777 		union xfs_btree_key	*lkp;
3778 		union xfs_btree_ptr	*lpp;
3779 
3780 		lkp = xfs_btree_key_addr(cur, ptr + 1, block);
3781 		lpp = xfs_btree_ptr_addr(cur, ptr + 1, block);
3782 
3783 		for (i = 0; i < numrecs - ptr; i++) {
3784 			error = xfs_btree_debug_check_ptr(cur, lpp, i, level);
3785 			if (error)
3786 				goto error0;
3787 		}
3788 
3789 		if (ptr < numrecs) {
3790 			xfs_btree_shift_keys(cur, lkp, -1, numrecs - ptr);
3791 			xfs_btree_shift_ptrs(cur, lpp, -1, numrecs - ptr);
3792 			xfs_btree_log_keys(cur, bp, ptr, numrecs - 1);
3793 			xfs_btree_log_ptrs(cur, bp, ptr, numrecs - 1);
3794 		}
3795 	} else {
3796 		/* It's a leaf. operate on records */
3797 		if (ptr < numrecs) {
3798 			xfs_btree_shift_recs(cur,
3799 				xfs_btree_rec_addr(cur, ptr + 1, block),
3800 				-1, numrecs - ptr);
3801 			xfs_btree_log_recs(cur, bp, ptr, numrecs - 1);
3802 		}
3803 	}
3804 
3805 	/*
3806 	 * Decrement and log the number of entries in the block.
3807 	 */
3808 	xfs_btree_set_numrecs(block, --numrecs);
3809 	xfs_btree_log_block(cur, bp, XFS_BB_NUMRECS);
3810 
3811 	/*
3812 	 * If we are tracking the last record in the tree and
3813 	 * we are at the far right edge of the tree, update it.
3814 	 */
3815 	if (xfs_btree_is_lastrec(cur, block, level)) {
3816 		cur->bc_ops->update_lastrec(cur, block, NULL,
3817 					    ptr, LASTREC_DELREC);
3818 	}
3819 
3820 	/*
3821 	 * We're at the root level.  First, shrink the root block in-memory.
3822 	 * Try to get rid of the next level down.  If we can't then there's
3823 	 * nothing left to do.
3824 	 */
3825 	if (level == cur->bc_nlevels - 1) {
3826 		if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) {
3827 			xfs_iroot_realloc(cur->bc_ino.ip, -1,
3828 					  cur->bc_ino.whichfork);
3829 
3830 			error = xfs_btree_kill_iroot(cur);
3831 			if (error)
3832 				goto error0;
3833 
3834 			error = xfs_btree_dec_cursor(cur, level, stat);
3835 			if (error)
3836 				goto error0;
3837 			*stat = 1;
3838 			return 0;
3839 		}
3840 
3841 		/*
3842 		 * If this is the root level, and there's only one entry left,
3843 		 * and it's NOT the leaf level, then we can get rid of this
3844 		 * level.
3845 		 */
3846 		if (numrecs == 1 && level > 0) {
3847 			union xfs_btree_ptr	*pp;
3848 			/*
3849 			 * pp is still set to the first pointer in the block.
3850 			 * Make it the new root of the btree.
3851 			 */
3852 			pp = xfs_btree_ptr_addr(cur, 1, block);
3853 			error = xfs_btree_kill_root(cur, bp, level, pp);
3854 			if (error)
3855 				goto error0;
3856 		} else if (level > 0) {
3857 			error = xfs_btree_dec_cursor(cur, level, stat);
3858 			if (error)
3859 				goto error0;
3860 		}
3861 		*stat = 1;
3862 		return 0;
3863 	}
3864 
3865 	/*
3866 	 * If we deleted the leftmost entry in the block, update the
3867 	 * key values above us in the tree.
3868 	 */
3869 	if (xfs_btree_needs_key_update(cur, ptr)) {
3870 		error = xfs_btree_update_keys(cur, level);
3871 		if (error)
3872 			goto error0;
3873 	}
3874 
3875 	/*
3876 	 * If the number of records remaining in the block is at least
3877 	 * the minimum, we're done.
3878 	 */
3879 	if (numrecs >= cur->bc_ops->get_minrecs(cur, level)) {
3880 		error = xfs_btree_dec_cursor(cur, level, stat);
3881 		if (error)
3882 			goto error0;
3883 		return 0;
3884 	}
3885 
3886 	/*
3887 	 * Otherwise, we have to move some records around to keep the
3888 	 * tree balanced.  Look at the left and right sibling blocks to
3889 	 * see if we can re-balance by moving only one record.
3890 	 */
3891 	xfs_btree_get_sibling(cur, block, &rptr, XFS_BB_RIGHTSIB);
3892 	xfs_btree_get_sibling(cur, block, &lptr, XFS_BB_LEFTSIB);
3893 
3894 	if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) {
3895 		/*
3896 		 * One child of root, need to get a chance to copy its contents
3897 		 * into the root and delete it. Can't go up to next level,
3898 		 * there's nothing to delete there.
3899 		 */
3900 		if (xfs_btree_ptr_is_null(cur, &rptr) &&
3901 		    xfs_btree_ptr_is_null(cur, &lptr) &&
3902 		    level == cur->bc_nlevels - 2) {
3903 			error = xfs_btree_kill_iroot(cur);
3904 			if (!error)
3905 				error = xfs_btree_dec_cursor(cur, level, stat);
3906 			if (error)
3907 				goto error0;
3908 			return 0;
3909 		}
3910 	}
3911 
3912 	ASSERT(!xfs_btree_ptr_is_null(cur, &rptr) ||
3913 	       !xfs_btree_ptr_is_null(cur, &lptr));
3914 
3915 	/*
3916 	 * Duplicate the cursor so our btree manipulations here won't
3917 	 * disrupt the next level up.
3918 	 */
3919 	error = xfs_btree_dup_cursor(cur, &tcur);
3920 	if (error)
3921 		goto error0;
3922 
3923 	/*
3924 	 * If there's a right sibling, see if it's ok to shift an entry
3925 	 * out of it.
3926 	 */
3927 	if (!xfs_btree_ptr_is_null(cur, &rptr)) {
3928 		/*
3929 		 * Move the temp cursor to the last entry in the next block.
3930 		 * Actually any entry but the first would suffice.
3931 		 */
3932 		i = xfs_btree_lastrec(tcur, level);
3933 		if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
3934 			error = -EFSCORRUPTED;
3935 			goto error0;
3936 		}
3937 
3938 		error = xfs_btree_increment(tcur, level, &i);
3939 		if (error)
3940 			goto error0;
3941 		if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
3942 			error = -EFSCORRUPTED;
3943 			goto error0;
3944 		}
3945 
3946 		i = xfs_btree_lastrec(tcur, level);
3947 		if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
3948 			error = -EFSCORRUPTED;
3949 			goto error0;
3950 		}
3951 
3952 		/* Grab a pointer to the block. */
3953 		right = xfs_btree_get_block(tcur, level, &rbp);
3954 #ifdef DEBUG
3955 		error = xfs_btree_check_block(tcur, right, level, rbp);
3956 		if (error)
3957 			goto error0;
3958 #endif
3959 		/* Grab the current block number, for future use. */
3960 		xfs_btree_get_sibling(tcur, right, &cptr, XFS_BB_LEFTSIB);
3961 
3962 		/*
3963 		 * If right block is full enough so that removing one entry
3964 		 * won't make it too empty, and left-shifting an entry out
3965 		 * of right to us works, we're done.
3966 		 */
3967 		if (xfs_btree_get_numrecs(right) - 1 >=
3968 		    cur->bc_ops->get_minrecs(tcur, level)) {
3969 			error = xfs_btree_lshift(tcur, level, &i);
3970 			if (error)
3971 				goto error0;
3972 			if (i) {
3973 				ASSERT(xfs_btree_get_numrecs(block) >=
3974 				       cur->bc_ops->get_minrecs(tcur, level));
3975 
3976 				xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
3977 				tcur = NULL;
3978 
3979 				error = xfs_btree_dec_cursor(cur, level, stat);
3980 				if (error)
3981 					goto error0;
3982 				return 0;
3983 			}
3984 		}
3985 
3986 		/*
3987 		 * Otherwise, grab the number of records in right for
3988 		 * future reference, and fix up the temp cursor to point
3989 		 * to our block again (last record).
3990 		 */
3991 		rrecs = xfs_btree_get_numrecs(right);
3992 		if (!xfs_btree_ptr_is_null(cur, &lptr)) {
3993 			i = xfs_btree_firstrec(tcur, level);
3994 			if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
3995 				error = -EFSCORRUPTED;
3996 				goto error0;
3997 			}
3998 
3999 			error = xfs_btree_decrement(tcur, level, &i);
4000 			if (error)
4001 				goto error0;
4002 			if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
4003 				error = -EFSCORRUPTED;
4004 				goto error0;
4005 			}
4006 		}
4007 	}
4008 
4009 	/*
4010 	 * If there's a left sibling, see if it's ok to shift an entry
4011 	 * out of it.
4012 	 */
4013 	if (!xfs_btree_ptr_is_null(cur, &lptr)) {
4014 		/*
4015 		 * Move the temp cursor to the first entry in the
4016 		 * previous block.
4017 		 */
4018 		i = xfs_btree_firstrec(tcur, level);
4019 		if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
4020 			error = -EFSCORRUPTED;
4021 			goto error0;
4022 		}
4023 
4024 		error = xfs_btree_decrement(tcur, level, &i);
4025 		if (error)
4026 			goto error0;
4027 		i = xfs_btree_firstrec(tcur, level);
4028 		if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
4029 			error = -EFSCORRUPTED;
4030 			goto error0;
4031 		}
4032 
4033 		/* Grab a pointer to the block. */
4034 		left = xfs_btree_get_block(tcur, level, &lbp);
4035 #ifdef DEBUG
4036 		error = xfs_btree_check_block(cur, left, level, lbp);
4037 		if (error)
4038 			goto error0;
4039 #endif
4040 		/* Grab the current block number, for future use. */
4041 		xfs_btree_get_sibling(tcur, left, &cptr, XFS_BB_RIGHTSIB);
4042 
4043 		/*
4044 		 * If left block is full enough so that removing one entry
4045 		 * won't make it too empty, and right-shifting an entry out
4046 		 * of left to us works, we're done.
4047 		 */
4048 		if (xfs_btree_get_numrecs(left) - 1 >=
4049 		    cur->bc_ops->get_minrecs(tcur, level)) {
4050 			error = xfs_btree_rshift(tcur, level, &i);
4051 			if (error)
4052 				goto error0;
4053 			if (i) {
4054 				ASSERT(xfs_btree_get_numrecs(block) >=
4055 				       cur->bc_ops->get_minrecs(tcur, level));
4056 				xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
4057 				tcur = NULL;
4058 				if (level == 0)
4059 					cur->bc_levels[0].ptr++;
4060 
4061 				*stat = 1;
4062 				return 0;
4063 			}
4064 		}
4065 
4066 		/*
4067 		 * Otherwise, grab the number of records in right for
4068 		 * future reference.
4069 		 */
4070 		lrecs = xfs_btree_get_numrecs(left);
4071 	}
4072 
4073 	/* Delete the temp cursor, we're done with it. */
4074 	xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
4075 	tcur = NULL;
4076 
4077 	/* If here, we need to do a join to keep the tree balanced. */
4078 	ASSERT(!xfs_btree_ptr_is_null(cur, &cptr));
4079 
4080 	if (!xfs_btree_ptr_is_null(cur, &lptr) &&
4081 	    lrecs + xfs_btree_get_numrecs(block) <=
4082 			cur->bc_ops->get_maxrecs(cur, level)) {
4083 		/*
4084 		 * Set "right" to be the starting block,
4085 		 * "left" to be the left neighbor.
4086 		 */
4087 		rptr = cptr;
4088 		right = block;
4089 		rbp = bp;
4090 		error = xfs_btree_read_buf_block(cur, &lptr, 0, &left, &lbp);
4091 		if (error)
4092 			goto error0;
4093 
4094 	/*
4095 	 * If that won't work, see if we can join with the right neighbor block.
4096 	 */
4097 	} else if (!xfs_btree_ptr_is_null(cur, &rptr) &&
4098 		   rrecs + xfs_btree_get_numrecs(block) <=
4099 			cur->bc_ops->get_maxrecs(cur, level)) {
4100 		/*
4101 		 * Set "left" to be the starting block,
4102 		 * "right" to be the right neighbor.
4103 		 */
4104 		lptr = cptr;
4105 		left = block;
4106 		lbp = bp;
4107 		error = xfs_btree_read_buf_block(cur, &rptr, 0, &right, &rbp);
4108 		if (error)
4109 			goto error0;
4110 
4111 	/*
4112 	 * Otherwise, we can't fix the imbalance.
4113 	 * Just return.  This is probably a logic error, but it's not fatal.
4114 	 */
4115 	} else {
4116 		error = xfs_btree_dec_cursor(cur, level, stat);
4117 		if (error)
4118 			goto error0;
4119 		return 0;
4120 	}
4121 
4122 	rrecs = xfs_btree_get_numrecs(right);
4123 	lrecs = xfs_btree_get_numrecs(left);
4124 
4125 	/*
4126 	 * We're now going to join "left" and "right" by moving all the stuff
4127 	 * in "right" to "left" and deleting "right".
4128 	 */
4129 	XFS_BTREE_STATS_ADD(cur, moves, rrecs);
4130 	if (level > 0) {
4131 		/* It's a non-leaf.  Move keys and pointers. */
4132 		union xfs_btree_key	*lkp;	/* left btree key */
4133 		union xfs_btree_ptr	*lpp;	/* left address pointer */
4134 		union xfs_btree_key	*rkp;	/* right btree key */
4135 		union xfs_btree_ptr	*rpp;	/* right address pointer */
4136 
4137 		lkp = xfs_btree_key_addr(cur, lrecs + 1, left);
4138 		lpp = xfs_btree_ptr_addr(cur, lrecs + 1, left);
4139 		rkp = xfs_btree_key_addr(cur, 1, right);
4140 		rpp = xfs_btree_ptr_addr(cur, 1, right);
4141 
4142 		for (i = 1; i < rrecs; i++) {
4143 			error = xfs_btree_debug_check_ptr(cur, rpp, i, level);
4144 			if (error)
4145 				goto error0;
4146 		}
4147 
4148 		xfs_btree_copy_keys(cur, lkp, rkp, rrecs);
4149 		xfs_btree_copy_ptrs(cur, lpp, rpp, rrecs);
4150 
4151 		xfs_btree_log_keys(cur, lbp, lrecs + 1, lrecs + rrecs);
4152 		xfs_btree_log_ptrs(cur, lbp, lrecs + 1, lrecs + rrecs);
4153 	} else {
4154 		/* It's a leaf.  Move records.  */
4155 		union xfs_btree_rec	*lrp;	/* left record pointer */
4156 		union xfs_btree_rec	*rrp;	/* right record pointer */
4157 
4158 		lrp = xfs_btree_rec_addr(cur, lrecs + 1, left);
4159 		rrp = xfs_btree_rec_addr(cur, 1, right);
4160 
4161 		xfs_btree_copy_recs(cur, lrp, rrp, rrecs);
4162 		xfs_btree_log_recs(cur, lbp, lrecs + 1, lrecs + rrecs);
4163 	}
4164 
4165 	XFS_BTREE_STATS_INC(cur, join);
4166 
4167 	/*
4168 	 * Fix up the number of records and right block pointer in the
4169 	 * surviving block, and log it.
4170 	 */
4171 	xfs_btree_set_numrecs(left, lrecs + rrecs);
4172 	xfs_btree_get_sibling(cur, right, &cptr, XFS_BB_RIGHTSIB);
4173 	xfs_btree_set_sibling(cur, left, &cptr, XFS_BB_RIGHTSIB);
4174 	xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS | XFS_BB_RIGHTSIB);
4175 
4176 	/* If there is a right sibling, point it to the remaining block. */
4177 	xfs_btree_get_sibling(cur, left, &cptr, XFS_BB_RIGHTSIB);
4178 	if (!xfs_btree_ptr_is_null(cur, &cptr)) {
4179 		error = xfs_btree_read_buf_block(cur, &cptr, 0, &rrblock, &rrbp);
4180 		if (error)
4181 			goto error0;
4182 		xfs_btree_set_sibling(cur, rrblock, &lptr, XFS_BB_LEFTSIB);
4183 		xfs_btree_log_block(cur, rrbp, XFS_BB_LEFTSIB);
4184 	}
4185 
4186 	/* Free the deleted block. */
4187 	error = xfs_btree_free_block(cur, rbp);
4188 	if (error)
4189 		goto error0;
4190 
4191 	/*
4192 	 * If we joined with the left neighbor, set the buffer in the
4193 	 * cursor to the left block, and fix up the index.
4194 	 */
4195 	if (bp != lbp) {
4196 		cur->bc_levels[level].bp = lbp;
4197 		cur->bc_levels[level].ptr += lrecs;
4198 		cur->bc_levels[level].ra = 0;
4199 	}
4200 	/*
4201 	 * If we joined with the right neighbor and there's a level above
4202 	 * us, increment the cursor at that level.
4203 	 */
4204 	else if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) ||
4205 		   (level + 1 < cur->bc_nlevels)) {
4206 		error = xfs_btree_increment(cur, level + 1, &i);
4207 		if (error)
4208 			goto error0;
4209 	}
4210 
4211 	/*
4212 	 * Readjust the ptr at this level if it's not a leaf, since it's
4213 	 * still pointing at the deletion point, which makes the cursor
4214 	 * inconsistent.  If this makes the ptr 0, the caller fixes it up.
4215 	 * We can't use decrement because it would change the next level up.
4216 	 */
4217 	if (level > 0)
4218 		cur->bc_levels[level].ptr--;
4219 
4220 	/*
4221 	 * We combined blocks, so we have to update the parent keys if the
4222 	 * btree supports overlapped intervals.  However,
4223 	 * bc_levels[level + 1].ptr points to the old block so that the caller
4224 	 * knows which record to delete.  Therefore, the caller must be savvy
4225 	 * enough to call updkeys for us if we return stat == 2.  The other
4226 	 * exit points from this function don't require deletions further up
4227 	 * the tree, so they can call updkeys directly.
4228 	 */
4229 
4230 	/* Return value means the next level up has something to do. */
4231 	*stat = 2;
4232 	return 0;
4233 
4234 error0:
4235 	if (tcur)
4236 		xfs_btree_del_cursor(tcur, XFS_BTREE_ERROR);
4237 	return error;
4238 }
4239 
4240 /*
4241  * Delete the record pointed to by cur.
4242  * The cursor refers to the place where the record was (could be inserted)
4243  * when the operation returns.
4244  */
4245 int					/* error */
xfs_btree_delete(struct xfs_btree_cur * cur,int * stat)4246 xfs_btree_delete(
4247 	struct xfs_btree_cur	*cur,
4248 	int			*stat)	/* success/failure */
4249 {
4250 	int			error;	/* error return value */
4251 	int			level;
4252 	int			i;
4253 	bool			joined = false;
4254 
4255 	/*
4256 	 * Go up the tree, starting at leaf level.
4257 	 *
4258 	 * If 2 is returned then a join was done; go to the next level.
4259 	 * Otherwise we are done.
4260 	 */
4261 	for (level = 0, i = 2; i == 2; level++) {
4262 		error = xfs_btree_delrec(cur, level, &i);
4263 		if (error)
4264 			goto error0;
4265 		if (i == 2)
4266 			joined = true;
4267 	}
4268 
4269 	/*
4270 	 * If we combined blocks as part of deleting the record, delrec won't
4271 	 * have updated the parent high keys so we have to do that here.
4272 	 */
4273 	if (joined && (cur->bc_flags & XFS_BTREE_OVERLAPPING)) {
4274 		error = xfs_btree_updkeys_force(cur, 0);
4275 		if (error)
4276 			goto error0;
4277 	}
4278 
4279 	if (i == 0) {
4280 		for (level = 1; level < cur->bc_nlevels; level++) {
4281 			if (cur->bc_levels[level].ptr == 0) {
4282 				error = xfs_btree_decrement(cur, level, &i);
4283 				if (error)
4284 					goto error0;
4285 				break;
4286 			}
4287 		}
4288 	}
4289 
4290 	*stat = i;
4291 	return 0;
4292 error0:
4293 	return error;
4294 }
4295 
4296 /*
4297  * Get the data from the pointed-to record.
4298  */
4299 int					/* error */
xfs_btree_get_rec(struct xfs_btree_cur * cur,union xfs_btree_rec ** recp,int * stat)4300 xfs_btree_get_rec(
4301 	struct xfs_btree_cur	*cur,	/* btree cursor */
4302 	union xfs_btree_rec	**recp,	/* output: btree record */
4303 	int			*stat)	/* output: success/failure */
4304 {
4305 	struct xfs_btree_block	*block;	/* btree block */
4306 	struct xfs_buf		*bp;	/* buffer pointer */
4307 	int			ptr;	/* record number */
4308 #ifdef DEBUG
4309 	int			error;	/* error return value */
4310 #endif
4311 
4312 	ptr = cur->bc_levels[0].ptr;
4313 	block = xfs_btree_get_block(cur, 0, &bp);
4314 
4315 #ifdef DEBUG
4316 	error = xfs_btree_check_block(cur, block, 0, bp);
4317 	if (error)
4318 		return error;
4319 #endif
4320 
4321 	/*
4322 	 * Off the right end or left end, return failure.
4323 	 */
4324 	if (ptr > xfs_btree_get_numrecs(block) || ptr <= 0) {
4325 		*stat = 0;
4326 		return 0;
4327 	}
4328 
4329 	/*
4330 	 * Point to the record and extract its data.
4331 	 */
4332 	*recp = xfs_btree_rec_addr(cur, ptr, block);
4333 	*stat = 1;
4334 	return 0;
4335 }
4336 
4337 /* Visit a block in a btree. */
4338 STATIC int
xfs_btree_visit_block(struct xfs_btree_cur * cur,int level,xfs_btree_visit_blocks_fn fn,void * data)4339 xfs_btree_visit_block(
4340 	struct xfs_btree_cur		*cur,
4341 	int				level,
4342 	xfs_btree_visit_blocks_fn	fn,
4343 	void				*data)
4344 {
4345 	struct xfs_btree_block		*block;
4346 	struct xfs_buf			*bp;
4347 	union xfs_btree_ptr		rptr;
4348 	int				error;
4349 
4350 	/* do right sibling readahead */
4351 	xfs_btree_readahead(cur, level, XFS_BTCUR_RIGHTRA);
4352 	block = xfs_btree_get_block(cur, level, &bp);
4353 
4354 	/* process the block */
4355 	error = fn(cur, level, data);
4356 	if (error)
4357 		return error;
4358 
4359 	/* now read rh sibling block for next iteration */
4360 	xfs_btree_get_sibling(cur, block, &rptr, XFS_BB_RIGHTSIB);
4361 	if (xfs_btree_ptr_is_null(cur, &rptr))
4362 		return -ENOENT;
4363 
4364 	/*
4365 	 * We only visit blocks once in this walk, so we have to avoid the
4366 	 * internal xfs_btree_lookup_get_block() optimisation where it will
4367 	 * return the same block without checking if the right sibling points
4368 	 * back to us and creates a cyclic reference in the btree.
4369 	 */
4370 	if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
4371 		if (be64_to_cpu(rptr.l) == XFS_DADDR_TO_FSB(cur->bc_mp,
4372 							xfs_buf_daddr(bp)))
4373 			return -EFSCORRUPTED;
4374 	} else {
4375 		if (be32_to_cpu(rptr.s) == xfs_daddr_to_agbno(cur->bc_mp,
4376 							xfs_buf_daddr(bp)))
4377 			return -EFSCORRUPTED;
4378 	}
4379 	return xfs_btree_lookup_get_block(cur, level, &rptr, &block);
4380 }
4381 
4382 
4383 /* Visit every block in a btree. */
4384 int
xfs_btree_visit_blocks(struct xfs_btree_cur * cur,xfs_btree_visit_blocks_fn fn,unsigned int flags,void * data)4385 xfs_btree_visit_blocks(
4386 	struct xfs_btree_cur		*cur,
4387 	xfs_btree_visit_blocks_fn	fn,
4388 	unsigned int			flags,
4389 	void				*data)
4390 {
4391 	union xfs_btree_ptr		lptr;
4392 	int				level;
4393 	struct xfs_btree_block		*block = NULL;
4394 	int				error = 0;
4395 
4396 	cur->bc_ops->init_ptr_from_cur(cur, &lptr);
4397 
4398 	/* for each level */
4399 	for (level = cur->bc_nlevels - 1; level >= 0; level--) {
4400 		/* grab the left hand block */
4401 		error = xfs_btree_lookup_get_block(cur, level, &lptr, &block);
4402 		if (error)
4403 			return error;
4404 
4405 		/* readahead the left most block for the next level down */
4406 		if (level > 0) {
4407 			union xfs_btree_ptr     *ptr;
4408 
4409 			ptr = xfs_btree_ptr_addr(cur, 1, block);
4410 			xfs_btree_readahead_ptr(cur, ptr, 1);
4411 
4412 			/* save for the next iteration of the loop */
4413 			xfs_btree_copy_ptrs(cur, &lptr, ptr, 1);
4414 
4415 			if (!(flags & XFS_BTREE_VISIT_LEAVES))
4416 				continue;
4417 		} else if (!(flags & XFS_BTREE_VISIT_RECORDS)) {
4418 			continue;
4419 		}
4420 
4421 		/* for each buffer in the level */
4422 		do {
4423 			error = xfs_btree_visit_block(cur, level, fn, data);
4424 		} while (!error);
4425 
4426 		if (error != -ENOENT)
4427 			return error;
4428 	}
4429 
4430 	return 0;
4431 }
4432 
4433 /*
4434  * Change the owner of a btree.
4435  *
4436  * The mechanism we use here is ordered buffer logging. Because we don't know
4437  * how many buffers were are going to need to modify, we don't really want to
4438  * have to make transaction reservations for the worst case of every buffer in a
4439  * full size btree as that may be more space that we can fit in the log....
4440  *
4441  * We do the btree walk in the most optimal manner possible - we have sibling
4442  * pointers so we can just walk all the blocks on each level from left to right
4443  * in a single pass, and then move to the next level and do the same. We can
4444  * also do readahead on the sibling pointers to get IO moving more quickly,
4445  * though for slow disks this is unlikely to make much difference to performance
4446  * as the amount of CPU work we have to do before moving to the next block is
4447  * relatively small.
4448  *
4449  * For each btree block that we load, modify the owner appropriately, set the
4450  * buffer as an ordered buffer and log it appropriately. We need to ensure that
4451  * we mark the region we change dirty so that if the buffer is relogged in
4452  * a subsequent transaction the changes we make here as an ordered buffer are
4453  * correctly relogged in that transaction.  If we are in recovery context, then
4454  * just queue the modified buffer as delayed write buffer so the transaction
4455  * recovery completion writes the changes to disk.
4456  */
4457 struct xfs_btree_block_change_owner_info {
4458 	uint64_t		new_owner;
4459 	struct list_head	*buffer_list;
4460 };
4461 
4462 static int
xfs_btree_block_change_owner(struct xfs_btree_cur * cur,int level,void * data)4463 xfs_btree_block_change_owner(
4464 	struct xfs_btree_cur	*cur,
4465 	int			level,
4466 	void			*data)
4467 {
4468 	struct xfs_btree_block_change_owner_info	*bbcoi = data;
4469 	struct xfs_btree_block	*block;
4470 	struct xfs_buf		*bp;
4471 
4472 	/* modify the owner */
4473 	block = xfs_btree_get_block(cur, level, &bp);
4474 	if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
4475 		if (block->bb_u.l.bb_owner == cpu_to_be64(bbcoi->new_owner))
4476 			return 0;
4477 		block->bb_u.l.bb_owner = cpu_to_be64(bbcoi->new_owner);
4478 	} else {
4479 		if (block->bb_u.s.bb_owner == cpu_to_be32(bbcoi->new_owner))
4480 			return 0;
4481 		block->bb_u.s.bb_owner = cpu_to_be32(bbcoi->new_owner);
4482 	}
4483 
4484 	/*
4485 	 * If the block is a root block hosted in an inode, we might not have a
4486 	 * buffer pointer here and we shouldn't attempt to log the change as the
4487 	 * information is already held in the inode and discarded when the root
4488 	 * block is formatted into the on-disk inode fork. We still change it,
4489 	 * though, so everything is consistent in memory.
4490 	 */
4491 	if (!bp) {
4492 		ASSERT(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE);
4493 		ASSERT(level == cur->bc_nlevels - 1);
4494 		return 0;
4495 	}
4496 
4497 	if (cur->bc_tp) {
4498 		if (!xfs_trans_ordered_buf(cur->bc_tp, bp)) {
4499 			xfs_btree_log_block(cur, bp, XFS_BB_OWNER);
4500 			return -EAGAIN;
4501 		}
4502 	} else {
4503 		xfs_buf_delwri_queue(bp, bbcoi->buffer_list);
4504 	}
4505 
4506 	return 0;
4507 }
4508 
4509 int
xfs_btree_change_owner(struct xfs_btree_cur * cur,uint64_t new_owner,struct list_head * buffer_list)4510 xfs_btree_change_owner(
4511 	struct xfs_btree_cur	*cur,
4512 	uint64_t		new_owner,
4513 	struct list_head	*buffer_list)
4514 {
4515 	struct xfs_btree_block_change_owner_info	bbcoi;
4516 
4517 	bbcoi.new_owner = new_owner;
4518 	bbcoi.buffer_list = buffer_list;
4519 
4520 	return xfs_btree_visit_blocks(cur, xfs_btree_block_change_owner,
4521 			XFS_BTREE_VISIT_ALL, &bbcoi);
4522 }
4523 
4524 /* Verify the v5 fields of a long-format btree block. */
4525 xfs_failaddr_t
xfs_btree_lblock_v5hdr_verify(struct xfs_buf * bp,uint64_t owner)4526 xfs_btree_lblock_v5hdr_verify(
4527 	struct xfs_buf		*bp,
4528 	uint64_t		owner)
4529 {
4530 	struct xfs_mount	*mp = bp->b_mount;
4531 	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
4532 
4533 	if (!xfs_has_crc(mp))
4534 		return __this_address;
4535 	if (!uuid_equal(&block->bb_u.l.bb_uuid, &mp->m_sb.sb_meta_uuid))
4536 		return __this_address;
4537 	if (block->bb_u.l.bb_blkno != cpu_to_be64(xfs_buf_daddr(bp)))
4538 		return __this_address;
4539 	if (owner != XFS_RMAP_OWN_UNKNOWN &&
4540 	    be64_to_cpu(block->bb_u.l.bb_owner) != owner)
4541 		return __this_address;
4542 	return NULL;
4543 }
4544 
4545 /* Verify a long-format btree block. */
4546 xfs_failaddr_t
xfs_btree_lblock_verify(struct xfs_buf * bp,unsigned int max_recs)4547 xfs_btree_lblock_verify(
4548 	struct xfs_buf		*bp,
4549 	unsigned int		max_recs)
4550 {
4551 	struct xfs_mount	*mp = bp->b_mount;
4552 	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
4553 	xfs_fsblock_t		fsb;
4554 	xfs_failaddr_t		fa;
4555 
4556 	/* numrecs verification */
4557 	if (be16_to_cpu(block->bb_numrecs) > max_recs)
4558 		return __this_address;
4559 
4560 	/* sibling pointer verification */
4561 	fsb = XFS_DADDR_TO_FSB(mp, xfs_buf_daddr(bp));
4562 	fa = xfs_btree_check_lblock_siblings(mp, NULL, -1, fsb,
4563 			block->bb_u.l.bb_leftsib);
4564 	if (!fa)
4565 		fa = xfs_btree_check_lblock_siblings(mp, NULL, -1, fsb,
4566 				block->bb_u.l.bb_rightsib);
4567 	return fa;
4568 }
4569 
4570 /**
4571  * xfs_btree_sblock_v5hdr_verify() -- verify the v5 fields of a short-format
4572  *				      btree block
4573  *
4574  * @bp: buffer containing the btree block
4575  */
4576 xfs_failaddr_t
xfs_btree_sblock_v5hdr_verify(struct xfs_buf * bp)4577 xfs_btree_sblock_v5hdr_verify(
4578 	struct xfs_buf		*bp)
4579 {
4580 	struct xfs_mount	*mp = bp->b_mount;
4581 	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
4582 	struct xfs_perag	*pag = bp->b_pag;
4583 
4584 	if (!xfs_has_crc(mp))
4585 		return __this_address;
4586 	if (!uuid_equal(&block->bb_u.s.bb_uuid, &mp->m_sb.sb_meta_uuid))
4587 		return __this_address;
4588 	if (block->bb_u.s.bb_blkno != cpu_to_be64(xfs_buf_daddr(bp)))
4589 		return __this_address;
4590 	if (pag && be32_to_cpu(block->bb_u.s.bb_owner) != pag->pag_agno)
4591 		return __this_address;
4592 	return NULL;
4593 }
4594 
4595 /**
4596  * xfs_btree_sblock_verify() -- verify a short-format btree block
4597  *
4598  * @bp: buffer containing the btree block
4599  * @max_recs: maximum records allowed in this btree node
4600  */
4601 xfs_failaddr_t
xfs_btree_sblock_verify(struct xfs_buf * bp,unsigned int max_recs)4602 xfs_btree_sblock_verify(
4603 	struct xfs_buf		*bp,
4604 	unsigned int		max_recs)
4605 {
4606 	struct xfs_mount	*mp = bp->b_mount;
4607 	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
4608 	xfs_agblock_t		agbno;
4609 	xfs_failaddr_t		fa;
4610 
4611 	/* numrecs verification */
4612 	if (be16_to_cpu(block->bb_numrecs) > max_recs)
4613 		return __this_address;
4614 
4615 	/* sibling pointer verification */
4616 	agbno = xfs_daddr_to_agbno(mp, xfs_buf_daddr(bp));
4617 	fa = xfs_btree_check_sblock_siblings(bp->b_pag, NULL, -1, agbno,
4618 			block->bb_u.s.bb_leftsib);
4619 	if (!fa)
4620 		fa = xfs_btree_check_sblock_siblings(bp->b_pag, NULL, -1, agbno,
4621 				block->bb_u.s.bb_rightsib);
4622 	return fa;
4623 }
4624 
4625 /*
4626  * For the given limits on leaf and keyptr records per block, calculate the
4627  * height of the tree needed to index the number of leaf records.
4628  */
4629 unsigned int
xfs_btree_compute_maxlevels(const unsigned int * limits,unsigned long long records)4630 xfs_btree_compute_maxlevels(
4631 	const unsigned int	*limits,
4632 	unsigned long long	records)
4633 {
4634 	unsigned long long	level_blocks = howmany_64(records, limits[0]);
4635 	unsigned int		height = 1;
4636 
4637 	while (level_blocks > 1) {
4638 		level_blocks = howmany_64(level_blocks, limits[1]);
4639 		height++;
4640 	}
4641 
4642 	return height;
4643 }
4644 
4645 /*
4646  * For the given limits on leaf and keyptr records per block, calculate the
4647  * number of blocks needed to index the given number of leaf records.
4648  */
4649 unsigned long long
xfs_btree_calc_size(const unsigned int * limits,unsigned long long records)4650 xfs_btree_calc_size(
4651 	const unsigned int	*limits,
4652 	unsigned long long	records)
4653 {
4654 	unsigned long long	level_blocks = howmany_64(records, limits[0]);
4655 	unsigned long long	blocks = level_blocks;
4656 
4657 	while (level_blocks > 1) {
4658 		level_blocks = howmany_64(level_blocks, limits[1]);
4659 		blocks += level_blocks;
4660 	}
4661 
4662 	return blocks;
4663 }
4664 
4665 /*
4666  * Given a number of available blocks for the btree to consume with records and
4667  * pointers, calculate the height of the tree needed to index all the records
4668  * that space can hold based on the number of pointers each interior node
4669  * holds.
4670  *
4671  * We start by assuming a single level tree consumes a single block, then track
4672  * the number of blocks each node level consumes until we no longer have space
4673  * to store the next node level. At this point, we are indexing all the leaf
4674  * blocks in the space, and there's no more free space to split the tree any
4675  * further. That's our maximum btree height.
4676  */
4677 unsigned int
xfs_btree_space_to_height(const unsigned int * limits,unsigned long long leaf_blocks)4678 xfs_btree_space_to_height(
4679 	const unsigned int	*limits,
4680 	unsigned long long	leaf_blocks)
4681 {
4682 	/*
4683 	 * The root btree block can have fewer than minrecs pointers in it
4684 	 * because the tree might not be big enough to require that amount of
4685 	 * fanout. Hence it has a minimum size of 2 pointers, not limits[1].
4686 	 */
4687 	unsigned long long	node_blocks = 2;
4688 	unsigned long long	blocks_left = leaf_blocks - 1;
4689 	unsigned int		height = 1;
4690 
4691 	if (leaf_blocks < 1)
4692 		return 0;
4693 
4694 	while (node_blocks < blocks_left) {
4695 		blocks_left -= node_blocks;
4696 		node_blocks *= limits[1];
4697 		height++;
4698 	}
4699 
4700 	return height;
4701 }
4702 
4703 /*
4704  * Query a regular btree for all records overlapping a given interval.
4705  * Start with a LE lookup of the key of low_rec and return all records
4706  * until we find a record with a key greater than the key of high_rec.
4707  */
4708 STATIC int
xfs_btree_simple_query_range(struct xfs_btree_cur * cur,const union xfs_btree_key * low_key,const union xfs_btree_key * high_key,xfs_btree_query_range_fn fn,void * priv)4709 xfs_btree_simple_query_range(
4710 	struct xfs_btree_cur		*cur,
4711 	const union xfs_btree_key	*low_key,
4712 	const union xfs_btree_key	*high_key,
4713 	xfs_btree_query_range_fn	fn,
4714 	void				*priv)
4715 {
4716 	union xfs_btree_rec		*recp;
4717 	union xfs_btree_key		rec_key;
4718 	int				stat;
4719 	bool				firstrec = true;
4720 	int				error;
4721 
4722 	ASSERT(cur->bc_ops->init_high_key_from_rec);
4723 	ASSERT(cur->bc_ops->diff_two_keys);
4724 
4725 	/*
4726 	 * Find the leftmost record.  The btree cursor must be set
4727 	 * to the low record used to generate low_key.
4728 	 */
4729 	stat = 0;
4730 	error = xfs_btree_lookup(cur, XFS_LOOKUP_LE, &stat);
4731 	if (error)
4732 		goto out;
4733 
4734 	/* Nothing?  See if there's anything to the right. */
4735 	if (!stat) {
4736 		error = xfs_btree_increment(cur, 0, &stat);
4737 		if (error)
4738 			goto out;
4739 	}
4740 
4741 	while (stat) {
4742 		/* Find the record. */
4743 		error = xfs_btree_get_rec(cur, &recp, &stat);
4744 		if (error || !stat)
4745 			break;
4746 
4747 		/* Skip if low_key > high_key(rec). */
4748 		if (firstrec) {
4749 			cur->bc_ops->init_high_key_from_rec(&rec_key, recp);
4750 			firstrec = false;
4751 			if (xfs_btree_keycmp_gt(cur, low_key, &rec_key))
4752 				goto advloop;
4753 		}
4754 
4755 		/* Stop if low_key(rec) > high_key. */
4756 		cur->bc_ops->init_key_from_rec(&rec_key, recp);
4757 		if (xfs_btree_keycmp_gt(cur, &rec_key, high_key))
4758 			break;
4759 
4760 		/* Callback */
4761 		error = fn(cur, recp, priv);
4762 		if (error)
4763 			break;
4764 
4765 advloop:
4766 		/* Move on to the next record. */
4767 		error = xfs_btree_increment(cur, 0, &stat);
4768 		if (error)
4769 			break;
4770 	}
4771 
4772 out:
4773 	return error;
4774 }
4775 
4776 /*
4777  * Query an overlapped interval btree for all records overlapping a given
4778  * interval.  This function roughly follows the algorithm given in
4779  * "Interval Trees" of _Introduction to Algorithms_, which is section
4780  * 14.3 in the 2nd and 3rd editions.
4781  *
4782  * First, generate keys for the low and high records passed in.
4783  *
4784  * For any leaf node, generate the high and low keys for the record.
4785  * If the record keys overlap with the query low/high keys, pass the
4786  * record to the function iterator.
4787  *
4788  * For any internal node, compare the low and high keys of each
4789  * pointer against the query low/high keys.  If there's an overlap,
4790  * follow the pointer.
4791  *
4792  * As an optimization, we stop scanning a block when we find a low key
4793  * that is greater than the query's high key.
4794  */
4795 STATIC int
xfs_btree_overlapped_query_range(struct xfs_btree_cur * cur,const union xfs_btree_key * low_key,const union xfs_btree_key * high_key,xfs_btree_query_range_fn fn,void * priv)4796 xfs_btree_overlapped_query_range(
4797 	struct xfs_btree_cur		*cur,
4798 	const union xfs_btree_key	*low_key,
4799 	const union xfs_btree_key	*high_key,
4800 	xfs_btree_query_range_fn	fn,
4801 	void				*priv)
4802 {
4803 	union xfs_btree_ptr		ptr;
4804 	union xfs_btree_ptr		*pp;
4805 	union xfs_btree_key		rec_key;
4806 	union xfs_btree_key		rec_hkey;
4807 	union xfs_btree_key		*lkp;
4808 	union xfs_btree_key		*hkp;
4809 	union xfs_btree_rec		*recp;
4810 	struct xfs_btree_block		*block;
4811 	int				level;
4812 	struct xfs_buf			*bp;
4813 	int				i;
4814 	int				error;
4815 
4816 	/* Load the root of the btree. */
4817 	level = cur->bc_nlevels - 1;
4818 	cur->bc_ops->init_ptr_from_cur(cur, &ptr);
4819 	error = xfs_btree_lookup_get_block(cur, level, &ptr, &block);
4820 	if (error)
4821 		return error;
4822 	xfs_btree_get_block(cur, level, &bp);
4823 	trace_xfs_btree_overlapped_query_range(cur, level, bp);
4824 #ifdef DEBUG
4825 	error = xfs_btree_check_block(cur, block, level, bp);
4826 	if (error)
4827 		goto out;
4828 #endif
4829 	cur->bc_levels[level].ptr = 1;
4830 
4831 	while (level < cur->bc_nlevels) {
4832 		block = xfs_btree_get_block(cur, level, &bp);
4833 
4834 		/* End of node, pop back towards the root. */
4835 		if (cur->bc_levels[level].ptr >
4836 					be16_to_cpu(block->bb_numrecs)) {
4837 pop_up:
4838 			if (level < cur->bc_nlevels - 1)
4839 				cur->bc_levels[level + 1].ptr++;
4840 			level++;
4841 			continue;
4842 		}
4843 
4844 		if (level == 0) {
4845 			/* Handle a leaf node. */
4846 			recp = xfs_btree_rec_addr(cur, cur->bc_levels[0].ptr,
4847 					block);
4848 
4849 			cur->bc_ops->init_high_key_from_rec(&rec_hkey, recp);
4850 			cur->bc_ops->init_key_from_rec(&rec_key, recp);
4851 
4852 			/*
4853 			 * If (query's high key < record's low key), then there
4854 			 * are no more interesting records in this block.  Pop
4855 			 * up to the leaf level to find more record blocks.
4856 			 *
4857 			 * If (record's high key >= query's low key) and
4858 			 *    (query's high key >= record's low key), then
4859 			 * this record overlaps the query range; callback.
4860 			 */
4861 			if (xfs_btree_keycmp_lt(cur, high_key, &rec_key))
4862 				goto pop_up;
4863 			if (xfs_btree_keycmp_ge(cur, &rec_hkey, low_key)) {
4864 				error = fn(cur, recp, priv);
4865 				if (error)
4866 					break;
4867 			}
4868 			cur->bc_levels[level].ptr++;
4869 			continue;
4870 		}
4871 
4872 		/* Handle an internal node. */
4873 		lkp = xfs_btree_key_addr(cur, cur->bc_levels[level].ptr, block);
4874 		hkp = xfs_btree_high_key_addr(cur, cur->bc_levels[level].ptr,
4875 				block);
4876 		pp = xfs_btree_ptr_addr(cur, cur->bc_levels[level].ptr, block);
4877 
4878 		/*
4879 		 * If (query's high key < pointer's low key), then there are no
4880 		 * more interesting keys in this block.  Pop up one leaf level
4881 		 * to continue looking for records.
4882 		 *
4883 		 * If (pointer's high key >= query's low key) and
4884 		 *    (query's high key >= pointer's low key), then
4885 		 * this record overlaps the query range; follow pointer.
4886 		 */
4887 		if (xfs_btree_keycmp_lt(cur, high_key, lkp))
4888 			goto pop_up;
4889 		if (xfs_btree_keycmp_ge(cur, hkp, low_key)) {
4890 			level--;
4891 			error = xfs_btree_lookup_get_block(cur, level, pp,
4892 					&block);
4893 			if (error)
4894 				goto out;
4895 			xfs_btree_get_block(cur, level, &bp);
4896 			trace_xfs_btree_overlapped_query_range(cur, level, bp);
4897 #ifdef DEBUG
4898 			error = xfs_btree_check_block(cur, block, level, bp);
4899 			if (error)
4900 				goto out;
4901 #endif
4902 			cur->bc_levels[level].ptr = 1;
4903 			continue;
4904 		}
4905 		cur->bc_levels[level].ptr++;
4906 	}
4907 
4908 out:
4909 	/*
4910 	 * If we don't end this function with the cursor pointing at a record
4911 	 * block, a subsequent non-error cursor deletion will not release
4912 	 * node-level buffers, causing a buffer leak.  This is quite possible
4913 	 * with a zero-results range query, so release the buffers if we
4914 	 * failed to return any results.
4915 	 */
4916 	if (cur->bc_levels[0].bp == NULL) {
4917 		for (i = 0; i < cur->bc_nlevels; i++) {
4918 			if (cur->bc_levels[i].bp) {
4919 				xfs_trans_brelse(cur->bc_tp,
4920 						cur->bc_levels[i].bp);
4921 				cur->bc_levels[i].bp = NULL;
4922 				cur->bc_levels[i].ptr = 0;
4923 				cur->bc_levels[i].ra = 0;
4924 			}
4925 		}
4926 	}
4927 
4928 	return error;
4929 }
4930 
4931 static inline void
xfs_btree_key_from_irec(struct xfs_btree_cur * cur,union xfs_btree_key * key,const union xfs_btree_irec * irec)4932 xfs_btree_key_from_irec(
4933 	struct xfs_btree_cur		*cur,
4934 	union xfs_btree_key		*key,
4935 	const union xfs_btree_irec	*irec)
4936 {
4937 	union xfs_btree_rec		rec;
4938 
4939 	cur->bc_rec = *irec;
4940 	cur->bc_ops->init_rec_from_cur(cur, &rec);
4941 	cur->bc_ops->init_key_from_rec(key, &rec);
4942 }
4943 
4944 /*
4945  * Query a btree for all records overlapping a given interval of keys.  The
4946  * supplied function will be called with each record found; return one of the
4947  * XFS_BTREE_QUERY_RANGE_{CONTINUE,ABORT} values or the usual negative error
4948  * code.  This function returns -ECANCELED, zero, or a negative error code.
4949  */
4950 int
xfs_btree_query_range(struct xfs_btree_cur * cur,const union xfs_btree_irec * low_rec,const union xfs_btree_irec * high_rec,xfs_btree_query_range_fn fn,void * priv)4951 xfs_btree_query_range(
4952 	struct xfs_btree_cur		*cur,
4953 	const union xfs_btree_irec	*low_rec,
4954 	const union xfs_btree_irec	*high_rec,
4955 	xfs_btree_query_range_fn	fn,
4956 	void				*priv)
4957 {
4958 	union xfs_btree_key		low_key;
4959 	union xfs_btree_key		high_key;
4960 
4961 	/* Find the keys of both ends of the interval. */
4962 	xfs_btree_key_from_irec(cur, &high_key, high_rec);
4963 	xfs_btree_key_from_irec(cur, &low_key, low_rec);
4964 
4965 	/* Enforce low key <= high key. */
4966 	if (!xfs_btree_keycmp_le(cur, &low_key, &high_key))
4967 		return -EINVAL;
4968 
4969 	if (!(cur->bc_flags & XFS_BTREE_OVERLAPPING))
4970 		return xfs_btree_simple_query_range(cur, &low_key,
4971 				&high_key, fn, priv);
4972 	return xfs_btree_overlapped_query_range(cur, &low_key, &high_key,
4973 			fn, priv);
4974 }
4975 
4976 /* Query a btree for all records. */
4977 int
xfs_btree_query_all(struct xfs_btree_cur * cur,xfs_btree_query_range_fn fn,void * priv)4978 xfs_btree_query_all(
4979 	struct xfs_btree_cur		*cur,
4980 	xfs_btree_query_range_fn	fn,
4981 	void				*priv)
4982 {
4983 	union xfs_btree_key		low_key;
4984 	union xfs_btree_key		high_key;
4985 
4986 	memset(&cur->bc_rec, 0, sizeof(cur->bc_rec));
4987 	memset(&low_key, 0, sizeof(low_key));
4988 	memset(&high_key, 0xFF, sizeof(high_key));
4989 
4990 	return xfs_btree_simple_query_range(cur, &low_key, &high_key, fn, priv);
4991 }
4992 
4993 static int
xfs_btree_count_blocks_helper(struct xfs_btree_cur * cur,int level,void * data)4994 xfs_btree_count_blocks_helper(
4995 	struct xfs_btree_cur	*cur,
4996 	int			level,
4997 	void			*data)
4998 {
4999 	xfs_extlen_t		*blocks = data;
5000 	(*blocks)++;
5001 
5002 	return 0;
5003 }
5004 
5005 /* Count the blocks in a btree and return the result in *blocks. */
5006 int
xfs_btree_count_blocks(struct xfs_btree_cur * cur,xfs_extlen_t * blocks)5007 xfs_btree_count_blocks(
5008 	struct xfs_btree_cur	*cur,
5009 	xfs_extlen_t		*blocks)
5010 {
5011 	*blocks = 0;
5012 	return xfs_btree_visit_blocks(cur, xfs_btree_count_blocks_helper,
5013 			XFS_BTREE_VISIT_ALL, blocks);
5014 }
5015 
5016 /* Compare two btree pointers. */
5017 int64_t
xfs_btree_diff_two_ptrs(struct xfs_btree_cur * cur,const union xfs_btree_ptr * a,const union xfs_btree_ptr * b)5018 xfs_btree_diff_two_ptrs(
5019 	struct xfs_btree_cur		*cur,
5020 	const union xfs_btree_ptr	*a,
5021 	const union xfs_btree_ptr	*b)
5022 {
5023 	if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
5024 		return (int64_t)be64_to_cpu(a->l) - be64_to_cpu(b->l);
5025 	return (int64_t)be32_to_cpu(a->s) - be32_to_cpu(b->s);
5026 }
5027 
5028 struct xfs_btree_has_records {
5029 	/* Keys for the start and end of the range we want to know about. */
5030 	union xfs_btree_key		start_key;
5031 	union xfs_btree_key		end_key;
5032 
5033 	/* Mask for key comparisons, if desired. */
5034 	const union xfs_btree_key	*key_mask;
5035 
5036 	/* Highest record key we've seen so far. */
5037 	union xfs_btree_key		high_key;
5038 
5039 	enum xbtree_recpacking		outcome;
5040 };
5041 
5042 STATIC int
xfs_btree_has_records_helper(struct xfs_btree_cur * cur,const union xfs_btree_rec * rec,void * priv)5043 xfs_btree_has_records_helper(
5044 	struct xfs_btree_cur		*cur,
5045 	const union xfs_btree_rec	*rec,
5046 	void				*priv)
5047 {
5048 	union xfs_btree_key		rec_key;
5049 	union xfs_btree_key		rec_high_key;
5050 	struct xfs_btree_has_records	*info = priv;
5051 	enum xbtree_key_contig		key_contig;
5052 
5053 	cur->bc_ops->init_key_from_rec(&rec_key, rec);
5054 
5055 	if (info->outcome == XBTREE_RECPACKING_EMPTY) {
5056 		info->outcome = XBTREE_RECPACKING_SPARSE;
5057 
5058 		/*
5059 		 * If the first record we find does not overlap the start key,
5060 		 * then there is a hole at the start of the search range.
5061 		 * Classify this as sparse and stop immediately.
5062 		 */
5063 		if (xfs_btree_masked_keycmp_lt(cur, &info->start_key, &rec_key,
5064 					info->key_mask))
5065 			return -ECANCELED;
5066 	} else {
5067 		/*
5068 		 * If a subsequent record does not overlap with the any record
5069 		 * we've seen so far, there is a hole in the middle of the
5070 		 * search range.  Classify this as sparse and stop.
5071 		 * If the keys overlap and this btree does not allow overlap,
5072 		 * signal corruption.
5073 		 */
5074 		key_contig = cur->bc_ops->keys_contiguous(cur, &info->high_key,
5075 					&rec_key, info->key_mask);
5076 		if (key_contig == XBTREE_KEY_OVERLAP &&
5077 				!(cur->bc_flags & XFS_BTREE_OVERLAPPING))
5078 			return -EFSCORRUPTED;
5079 		if (key_contig == XBTREE_KEY_GAP)
5080 			return -ECANCELED;
5081 	}
5082 
5083 	/*
5084 	 * If high_key(rec) is larger than any other high key we've seen,
5085 	 * remember it for later.
5086 	 */
5087 	cur->bc_ops->init_high_key_from_rec(&rec_high_key, rec);
5088 	if (xfs_btree_masked_keycmp_gt(cur, &rec_high_key, &info->high_key,
5089 				info->key_mask))
5090 		info->high_key = rec_high_key; /* struct copy */
5091 
5092 	return 0;
5093 }
5094 
5095 /*
5096  * Scan part of the keyspace of a btree and tell us if that keyspace does not
5097  * map to any records; is fully mapped to records; or is partially mapped to
5098  * records.  This is the btree record equivalent to determining if a file is
5099  * sparse.
5100  *
5101  * For most btree types, the record scan should use all available btree key
5102  * fields to compare the keys encountered.  These callers should pass NULL for
5103  * @mask.  However, some callers (e.g.  scanning physical space in the rmapbt)
5104  * want to ignore some part of the btree record keyspace when performing the
5105  * comparison.  These callers should pass in a union xfs_btree_key object with
5106  * the fields that *should* be a part of the comparison set to any nonzero
5107  * value, and the rest zeroed.
5108  */
5109 int
xfs_btree_has_records(struct xfs_btree_cur * cur,const union xfs_btree_irec * low,const union xfs_btree_irec * high,const union xfs_btree_key * mask,enum xbtree_recpacking * outcome)5110 xfs_btree_has_records(
5111 	struct xfs_btree_cur		*cur,
5112 	const union xfs_btree_irec	*low,
5113 	const union xfs_btree_irec	*high,
5114 	const union xfs_btree_key	*mask,
5115 	enum xbtree_recpacking		*outcome)
5116 {
5117 	struct xfs_btree_has_records	info = {
5118 		.outcome		= XBTREE_RECPACKING_EMPTY,
5119 		.key_mask		= mask,
5120 	};
5121 	int				error;
5122 
5123 	/* Not all btrees support this operation. */
5124 	if (!cur->bc_ops->keys_contiguous) {
5125 		ASSERT(0);
5126 		return -EOPNOTSUPP;
5127 	}
5128 
5129 	xfs_btree_key_from_irec(cur, &info.start_key, low);
5130 	xfs_btree_key_from_irec(cur, &info.end_key, high);
5131 
5132 	error = xfs_btree_query_range(cur, low, high,
5133 			xfs_btree_has_records_helper, &info);
5134 	if (error == -ECANCELED)
5135 		goto out;
5136 	if (error)
5137 		return error;
5138 
5139 	if (info.outcome == XBTREE_RECPACKING_EMPTY)
5140 		goto out;
5141 
5142 	/*
5143 	 * If the largest high_key(rec) we saw during the walk is greater than
5144 	 * the end of the search range, classify this as full.  Otherwise,
5145 	 * there is a hole at the end of the search range.
5146 	 */
5147 	if (xfs_btree_masked_keycmp_ge(cur, &info.high_key, &info.end_key,
5148 				mask))
5149 		info.outcome = XBTREE_RECPACKING_FULL;
5150 
5151 out:
5152 	*outcome = info.outcome;
5153 	return 0;
5154 }
5155 
5156 /* Are there more records in this btree? */
5157 bool
xfs_btree_has_more_records(struct xfs_btree_cur * cur)5158 xfs_btree_has_more_records(
5159 	struct xfs_btree_cur	*cur)
5160 {
5161 	struct xfs_btree_block	*block;
5162 	struct xfs_buf		*bp;
5163 
5164 	block = xfs_btree_get_block(cur, 0, &bp);
5165 
5166 	/* There are still records in this block. */
5167 	if (cur->bc_levels[0].ptr < xfs_btree_get_numrecs(block))
5168 		return true;
5169 
5170 	/* There are more record blocks. */
5171 	if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
5172 		return block->bb_u.l.bb_rightsib != cpu_to_be64(NULLFSBLOCK);
5173 	else
5174 		return block->bb_u.s.bb_rightsib != cpu_to_be32(NULLAGBLOCK);
5175 }
5176 
5177 /* Set up all the btree cursor caches. */
5178 int __init
xfs_btree_init_cur_caches(void)5179 xfs_btree_init_cur_caches(void)
5180 {
5181 	int		error;
5182 
5183 	error = xfs_allocbt_init_cur_cache();
5184 	if (error)
5185 		return error;
5186 	error = xfs_inobt_init_cur_cache();
5187 	if (error)
5188 		goto err;
5189 	error = xfs_bmbt_init_cur_cache();
5190 	if (error)
5191 		goto err;
5192 	error = xfs_rmapbt_init_cur_cache();
5193 	if (error)
5194 		goto err;
5195 	error = xfs_refcountbt_init_cur_cache();
5196 	if (error)
5197 		goto err;
5198 
5199 	return 0;
5200 err:
5201 	xfs_btree_destroy_cur_caches();
5202 	return error;
5203 }
5204 
5205 /* Destroy all the btree cursor caches, if they've been allocated. */
5206 void
xfs_btree_destroy_cur_caches(void)5207 xfs_btree_destroy_cur_caches(void)
5208 {
5209 	xfs_allocbt_destroy_cur_cache();
5210 	xfs_inobt_destroy_cur_cache();
5211 	xfs_bmbt_destroy_cur_cache();
5212 	xfs_rmapbt_destroy_cur_cache();
5213 	xfs_refcountbt_destroy_cur_cache();
5214 }
5215