aboutsummaryrefslogblamecommitdiffstats
path: root/fs/xfs/xfs_btree.c
blob: 26717388acf5a250c0ec8b039e041dbe753c0b77 (plain) (tree)
1
2
3
4
5
6
7
8
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
  

                                                      
  

                                                                 

                                             



                                                                   
  


                                                                       
   
                
                   
                      
                    
                    
                     


                      


                      
                           
                            
                             
                        
                        

                       
                           
                      
                            
                       









                                    
                                              


                                                                     
 
                                                                       

                                                          
                                                                           










                                                                            
                                                               







                                                                        











                                                                            
                                                                       
                       
                                                          
                                                                            
                                                                      
                                                                     
 

                                                                             




                                                                         
                                              
                   


                                                                            
                                                               





                                                                         




                                                           

                                                              





                                               








                                                                             



                                                                     

















                                                                       
            

                                    
   
                                                                       
                     


                                                                      
 
                                                                        
 

                                  


                                     



                 

                              
                                                                       













                                                                      
      

  






















































                                                                              
 


                                                  

                                           



                                                   
 


















                                                                                 




                    


































                                                                              

                                      




























































































                                                                             















                                                                              
                                                                 
                                                    
   
                                                                         
                    
                                                          
                                                            
                                                                         
 



                                                        
         


                                      
















































                                                                             






                                                                               
                                                                         



                                                                     
                                                
                                                                            
            
                                                                             


  


                                                                     
                                                                  



                                                             
                                                                         









                                                                     
                               








                                                               


                                                                     
                                                                  



                                                             
                                                                         









                                                                     
                               



                                                                    
                                                             



















































































































































                                                                             






                                         

                                                                               







































                                                                               



                                                    
          

                                                                  


                                                                     











                                                                  
 
                              




                                                                  











                                                                
                                                         









                                                                
                                                  
                                                                    
                                                            
                                                                     

                                                             
                                                                     
                                                            
                                                                      


                                                             






                                                
                                                         



                                                          





                                                
                                                 



                                                  
























                                                              

































                                                               

                                                                  





                                                                   























                                                                 









                                                                 
                                                                   



                                                           





                                                  
                                                          































                                                                            
























                                                                   






































                                                                       













                                                                 













                                                                 






































































                                                                         
























                                                                              

                                          
    
















                                                                   





























                                                                                
    







                                                                              





                                                                     

                                                                             





                                                                     



















                                                                         









































































































                                                                         


































































































                                                                         

























































































































































































































                                                                              



                                                                           
          









































                                                                         






























































                                                                              
  


                                                 
                                                           



























































                                                                               
                                                                              
































                                                                          

                                                                        









                                                                         

                                                                        






































































                                                                            


                                                  
                                                           


































































































                                                                               

                                                            
















                                                             

                                                            
















































                                                                          





                                                   
                                                           


















































































































































































                                                                                

  


























































































                                                                              
                                                                             








                                               

                                         
                                                   



























































































































                                                                               












































































































































                                                                              

                                                                      
                        

                                                                      




































































                                                                                

                                                                          















                                                                       

                                                                          



















































































































                                                                               










































































                                                                        
                                      





























                                                                    
                                                                              




                                              
































































































































































































































































































































































































































































































                                                                                
                                                                      














































































































                                                                            








































                                                                     
/*
 * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
 * All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_types.h"
#include "xfs_bit.h"
#include "xfs_log.h"
#include "xfs_inum.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_dir2.h"
#include "xfs_dmapi.h"
#include "xfs_mount.h"
#include "xfs_bmap_btree.h"
#include "xfs_alloc_btree.h"
#include "xfs_ialloc_btree.h"
#include "xfs_dir2_sf.h"
#include "xfs_attr_sf.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_inode_item.h"
#include "xfs_btree.h"
#include "xfs_btree_trace.h"
#include "xfs_ialloc.h"
#include "xfs_error.h"

/*
 * Cursor allocation zone.
 */
kmem_zone_t	*xfs_btree_cur_zone;

/*
 * Btree magic numbers.
 */
const __uint32_t xfs_magics[XFS_BTNUM_MAX] = {
	XFS_ABTB_MAGIC, XFS_ABTC_MAGIC, XFS_BMAP_MAGIC, XFS_IBT_MAGIC
};


STATIC int				/* error (0 or EFSCORRUPTED) */
xfs_btree_check_lblock(
	struct xfs_btree_cur	*cur,	/* btree cursor */
	struct xfs_btree_block	*block,	/* btree long form block pointer */
	int			level,	/* level of the btree block */
	struct xfs_buf		*bp)	/* buffer for block, if any */
{
	int			lblock_ok; /* block passes checks */
	struct xfs_mount	*mp;	/* file system mount point */

	mp = cur->bc_mp;
	lblock_ok =
		be32_to_cpu(block->bb_magic) == xfs_magics[cur->bc_btnum] &&
		be16_to_cpu(block->bb_level) == level &&
		be16_to_cpu(block->bb_numrecs) <=
			cur->bc_ops->get_maxrecs(cur, level) &&
		block->bb_u.l.bb_leftsib &&
		(be64_to_cpu(block->bb_u.l.bb_leftsib) == NULLDFSBNO ||
		 XFS_FSB_SANITY_CHECK(mp,
		 	be64_to_cpu(block->bb_u.l.bb_leftsib))) &&
		block->bb_u.l.bb_rightsib &&
		(be64_to_cpu(block->bb_u.l.bb_rightsib) == NULLDFSBNO ||
		 XFS_FSB_SANITY_CHECK(mp,
		 	be64_to_cpu(block->bb_u.l.bb_rightsib)));
	if (unlikely(XFS_TEST_ERROR(!lblock_ok, mp,
			XFS_ERRTAG_BTREE_CHECK_LBLOCK,
			XFS_RANDOM_BTREE_CHECK_LBLOCK))) {
		if (bp)
			xfs_buftrace("LBTREE ERROR", bp);
		XFS_ERROR_REPORT("xfs_btree_check_lblock", XFS_ERRLEVEL_LOW,
				 mp);
		return XFS_ERROR(EFSCORRUPTED);
	}
	return 0;
}

STATIC int				/* error (0 or EFSCORRUPTED) */
xfs_btree_check_sblock(
	struct xfs_btree_cur	*cur,	/* btree cursor */
	struct xfs_btree_block	*block,	/* btree short form block pointer */
	int			level,	/* level of the btree block */
	struct xfs_buf		*bp)	/* buffer containing block */
{
	struct xfs_buf		*agbp;	/* buffer for ag. freespace struct */
	struct xfs_agf		*agf;	/* ag. freespace structure */
	xfs_agblock_t		agflen;	/* native ag. freespace length */
	int			sblock_ok; /* block passes checks */

	agbp = cur->bc_private.a.agbp;
	agf = XFS_BUF_TO_AGF(agbp);
	agflen = be32_to_cpu(agf->agf_length);
	sblock_ok =
		be32_to_cpu(block->bb_magic) == xfs_magics[cur->bc_btnum] &&
		be16_to_cpu(block->bb_level) == level &&
		be16_to_cpu(block->bb_numrecs) <=
			cur->bc_ops->get_maxrecs(cur, level) &&
		(be32_to_cpu(block->bb_u.s.bb_leftsib) == NULLAGBLOCK ||
		 be32_to_cpu(block->bb_u.s.bb_leftsib) < agflen) &&
		block->bb_u.s.bb_leftsib &&
		(be32_to_cpu(block->bb_u.s.bb_rightsib) == NULLAGBLOCK ||
		 be32_to_cpu(block->bb_u.s.bb_rightsib) < agflen) &&
		block->bb_u.s.bb_rightsib;
	if (unlikely(XFS_TEST_ERROR(!sblock_ok, cur->bc_mp,
			XFS_ERRTAG_BTREE_CHECK_SBLOCK,
			XFS_RANDOM_BTREE_CHECK_SBLOCK))) {
		if (bp)
			xfs_buftrace("SBTREE ERROR", bp);
		XFS_CORRUPTION_ERROR("xfs_btree_check_sblock",
			XFS_ERRLEVEL_LOW, cur->bc_mp, block);
		return XFS_ERROR(EFSCORRUPTED);
	}
	return 0;
}

/*
 * Debug routine: check that block header is ok.
 */
int
xfs_btree_check_block(
	struct xfs_btree_cur	*cur,	/* btree cursor */
	struct xfs_btree_block	*block,	/* generic btree block pointer */
	int			level,	/* level of the btree block */
	struct xfs_buf		*bp)	/* buffer containing block, if any */
{
	if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
		return xfs_btree_check_lblock(cur, block, level, bp);
	else
		return xfs_btree_check_sblock(cur, block, level, bp);
}

/*
 * Check that (long) pointer is ok.
 */
int					/* error (0 or EFSCORRUPTED) */
xfs_btree_check_lptr(
	struct xfs_btree_cur	*cur,	/* btree cursor */
	xfs_dfsbno_t		bno,	/* btree block disk address */
	int			level)	/* btree block level */
{
	XFS_WANT_CORRUPTED_RETURN(
		level > 0 &&
		bno != NULLDFSBNO &&
		XFS_FSB_SANITY_CHECK(cur->bc_mp, bno));
	return 0;
}

#ifdef DEBUG
/*
 * Check that (short) pointer is ok.
 */
STATIC int				/* error (0 or EFSCORRUPTED) */
xfs_btree_check_sptr(
	struct xfs_btree_cur	*cur,	/* btree cursor */
	xfs_agblock_t		bno,	/* btree block disk address */
	int			level)	/* btree block level */
{
	xfs_agblock_t		agblocks = cur->bc_mp->m_sb.sb_agblocks;

	XFS_WANT_CORRUPTED_RETURN(
		level > 0 &&
		bno != NULLAGBLOCK &&
		bno != 0 &&
		bno < agblocks);
	return 0;
}

/*
 * Check that block ptr is ok.
 */
STATIC int				/* error (0 or EFSCORRUPTED) */
xfs_btree_check_ptr(
	struct xfs_btree_cur	*cur,	/* btree cursor */
	union xfs_btree_ptr	*ptr,	/* btree block disk address */
	int			index,	/* offset from ptr to check */
	int			level)	/* btree block level */
{
	if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
		return xfs_btree_check_lptr(cur,
				be64_to_cpu((&ptr->l)[index]), level);
	} else {
		return xfs_btree_check_sptr(cur,
				be32_to_cpu((&ptr->s)[index]), level);
	}
}
#endif

/*
 * Delete the btree cursor.
 */
void
xfs_btree_del_cursor(
	xfs_btree_cur_t	*cur,		/* btree cursor */
	int		error)		/* del because of error */
{
	int		i;		/* btree level */

	/*
	 * Clear the buffer pointers, and release the buffers.
	 * If we're doing this in the face of an error, we
	 * need to make sure to inspect all of the entries
	 * in the bc_bufs array for buffers to be unlocked.
	 * This is because some of the btree code works from
	 * level n down to 0, and if we get an error along
	 * the way we won't have initialized all the entries
	 * down to 0.
	 */
	for (i = 0; i < cur->bc_nlevels; i++) {
		if (cur->bc_bufs[i])
			xfs_btree_setbuf(cur, i, NULL);
		else if (!error)
			break;
	}
	/*
	 * Can't free a bmap cursor without having dealt with the
	 * allocated indirect blocks' accounting.
	 */
	ASSERT(cur->bc_btnum != XFS_BTNUM_BMAP ||
	       cur->bc_private.b.allocated == 0);
	/*
	 * Free the cursor.
	 */
	kmem_zone_free(xfs_btree_cur_zone, cur);
}

/*
 * Duplicate the btree cursor.
 * Allocate a new one, copy the record, re-get the buffers.
 */
int					/* error */
xfs_btree_dup_cursor(
	xfs_btree_cur_t	*cur,		/* input cursor */
	xfs_btree_cur_t	**ncur)		/* output cursor */
{
	xfs_buf_t	*bp;		/* btree block's buffer pointer */
	int		error;		/* error return value */
	int		i;		/* level number of btree block */
	xfs_mount_t	*mp;		/* mount structure for filesystem */
	xfs_btree_cur_t	*new;		/* new cursor value */
	xfs_trans_t	*tp;		/* transaction pointer, can be NULL */

	tp = cur->bc_tp;
	mp = cur->bc_mp;

	/*
	 * Allocate a new cursor like the old one.
	 */
	new = cur->bc_ops->dup_cursor(cur);

	/*
	 * Copy the record currently in the cursor.
	 */
	new->bc_rec = cur->bc_rec;

	/*
	 * For each level current, re-get the buffer and copy the ptr value.
	 */
	for (i = 0; i < new->bc_nlevels; i++) {
		new->bc_ptrs[i] = cur->bc_ptrs[i];
		new->bc_ra[i] = cur->bc_ra[i];
		if ((bp = cur->bc_bufs[i])) {
			if ((error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp,
				XFS_BUF_ADDR(bp), mp->m_bsize, 0, &bp))) {
				xfs_btree_del_cursor(new, error);
				*ncur = NULL;
				return error;
			}
			new->bc_bufs[i] = bp;
			ASSERT(bp);
			ASSERT(!XFS_BUF_GETERROR(bp));
		} else
			new->bc_bufs[i] = NULL;
	}
	*ncur = new;
	return 0;
}

/*
 * XFS btree block layout and addressing:
 *
 * There are two types of blocks in the btree: leaf and non-leaf blocks.
 *
 * The leaf record start with a header then followed by records containing
 * the values.  A non-leaf block also starts with the same header, and
 * then first contains lookup keys followed by an equal number of pointers
 * to the btree blocks at the previous level.
 *
 *		+--------+-------+-------+-------+-------+-------+-------+
 * Leaf:	| header | rec 1 | rec 2 | rec 3 | rec 4 | rec 5 | rec N |
 *		+--------+-------+-------+-------+-------+-------+-------+
 *
 *		+--------+-------+-------+-------+-------+-------+-------+
 * Non-Leaf:	| header | key 1 | key 2 | key N | ptr 1 | ptr 2 | ptr N |
 *		+--------+-------+-------+-------+-------+-------+-------+
 *
 * The header is called struct xfs_btree_block for reasons better left unknown
 * and comes in different versions for short (32bit) and long (64bit) block
 * pointers.  The record and key structures are defined by the btree instances
 * and opaque to the btree core.  The block pointers are simple disk endian
 * integers, available in a short (32bit) and long (64bit) variant.
 *
 * The helpers below calculate the offset of a given record, key or pointer
 * into a btree block (xfs_btree_*_offset) or return a pointer to the given
 * record, key or pointer (xfs_btree_*_addr).  Note that all addressing
 * inside the btree block is done using indices starting at one, not zero!
 */

/*
 * Return size of the btree block header for this btree instance.
 */
static inline size_t xfs_btree_block_len(struct xfs_btree_cur *cur)
{
	return (cur->bc_flags & XFS_BTREE_LONG_PTRS) ?
		XFS_BTREE_LBLOCK_LEN :
		XFS_BTREE_SBLOCK_LEN;
}

/*
 * Return size of btree block pointers for this btree instance.
 */
static inline size_t xfs_btree_ptr_len(struct xfs_btree_cur *cur)
{
	return (cur->bc_flags & XFS_BTREE_LONG_PTRS) ?
		sizeof(__be64) : sizeof(__be32);
}

/*
 * Calculate offset of the n-th record in a btree block.
 */
STATIC size_t
xfs_btree_rec_offset(
	struct xfs_btree_cur	*cur,
	int			n)
{
	return xfs_btree_block_len(cur) +
		(n - 1) * cur->bc_ops->rec_len;
}

/*
 * Calculate offset of the n-th key in a btree block.
 */
STATIC size_t
xfs_btree_key_offset(
	struct xfs_btree_cur	*cur,
	int			n)
{
	return xfs_btree_block_len(cur) +
		(n - 1) * cur->bc_ops->key_len;
}

/*
 * Calculate offset of the n-th block pointer in a btree block.
 */
STATIC size_t
xfs_btree_ptr_offset(
	struct xfs_btree_cur	*cur,
	int			n,
	int			level)
{
	return xfs_btree_block_len(cur) +
		cur->bc_ops->get_maxrecs(cur, level) * cur->bc_ops->key_len +
		(n - 1) * xfs_btree_ptr_len(cur);
}

/*
 * Return a pointer to the n-th record in the btree block.
 */
STATIC union xfs_btree_rec *
xfs_btree_rec_addr(
	struct xfs_btree_cur	*cur,
	int			n,
	struct xfs_btree_block	*block)
{
	return (union xfs_btree_rec *)
		((char *)block + xfs_btree_rec_offset(cur, n));
}

/*
 * Return a pointer to the n-th key in the btree block.
 */
STATIC union xfs_btree_key *
xfs_btree_key_addr(
	struct xfs_btree_cur	*cur,
	int			n,
	struct xfs_btree_block	*block)
{
	return (union xfs_btree_key *)
		((char *)block + xfs_btree_key_offset(cur, n));
}

/*
 * Return a pointer to the n-th block pointer in the btree block.
 */
STATIC union xfs_btree_ptr *
xfs_btree_ptr_addr(
	struct xfs_btree_cur	*cur,
	int			n,
	struct xfs_btree_block	*block)
{
	int			level = xfs_btree_get_level(block);

	ASSERT(block->bb_level != 0);

	return (union xfs_btree_ptr *)
		((char *)block + xfs_btree_ptr_offset(cur, n, level));
}

/*
 * Get a the root block which is stored in the inode.
 *
 * For now this btree implementation assumes the btree root is always
 * stored in the if_broot field of an inode fork.
 */
STATIC struct xfs_btree_block *
xfs_btree_get_iroot(
       struct xfs_btree_cur    *cur)
{
       struct xfs_ifork        *ifp;

       ifp = XFS_IFORK_PTR(cur->bc_private.b.ip, cur->bc_private.b.whichfork);
       return (struct xfs_btree_block *)ifp->if_broot;
}

/*
 * Retrieve the block pointer from the cursor at the given level.
 * This may be an inode btree root or from a buffer.
 */
STATIC struct xfs_btree_block *		/* generic btree block pointer */
xfs_btree_get_block(
	struct xfs_btree_cur	*cur,	/* btree cursor */
	int			level,	/* level in btree */
	struct xfs_buf		**bpp)	/* buffer containing the block */
{
	if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
	    (level == cur->bc_nlevels - 1)) {
		*bpp = NULL;
		return xfs_btree_get_iroot(cur);
	}

	*bpp = cur->bc_bufs[level];
	return XFS_BUF_TO_BLOCK(*bpp);
}

/*
 * Get a buffer for the block, return it with no data read.
 * Long-form addressing.
 */
xfs_buf_t *				/* buffer for fsbno */
xfs_btree_get_bufl(
	xfs_mount_t	*mp,		/* file system mount point */
	xfs_trans_t	*tp,		/* transaction pointer */
	xfs_fsblock_t	fsbno,		/* file system block number */
	uint		lock)		/* lock flags for get_buf */
{
	xfs_buf_t	*bp;		/* buffer pointer (return value) */
	xfs_daddr_t		d;		/* real disk block address */

	ASSERT(fsbno != NULLFSBLOCK);
	d = XFS_FSB_TO_DADDR(mp, fsbno);
	bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, d, mp->m_bsize, lock);
	ASSERT(bp);
	ASSERT(!XFS_BUF_GETERROR(bp));
	return bp;
}

/*
 * Get a buffer for the block, return it with no data read.
 * Short-form addressing.
 */
xfs_buf_t *				/* buffer for agno/agbno */
xfs_btree_get_bufs(
	xfs_mount_t	*mp,		/* file system mount point */
	xfs_trans_t	*tp,		/* transaction pointer */
	xfs_agnumber_t	agno,		/* allocation group number */
	xfs_agblock_t	agbno,		/* allocation group block number */
	uint		lock)		/* lock flags for get_buf */
{
	xfs_buf_t	*bp;		/* buffer pointer (return value) */
	xfs_daddr_t		d;		/* real disk block address */

	ASSERT(agno != NULLAGNUMBER);
	ASSERT(agbno != NULLAGBLOCK);
	d = XFS_AGB_TO_DADDR(mp, agno, agbno);
	bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, d, mp->m_bsize, lock);
	ASSERT(bp);
	ASSERT(!XFS_BUF_GETERROR(bp));
	return bp;
}

/*
 * Check for the cursor referring to the last block at the given level.
 */
int					/* 1=is last block, 0=not last block */
xfs_btree_islastblock(
	xfs_btree_cur_t		*cur,	/* btree cursor */
	int			level)	/* level to check */
{
	struct xfs_btree_block	*block;	/* generic btree block pointer */
	xfs_buf_t		*bp;	/* buffer containing block */

	block = xfs_btree_get_block(cur, level, &bp);
	xfs_btree_check_block(cur, block, level, bp);
	if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
		return be64_to_cpu(block->bb_u.l.bb_rightsib) == NULLDFSBNO;
	else
		return be32_to_cpu(block->bb_u.s.bb_rightsib) == NULLAGBLOCK;
}

/*
 * Change the cursor to point to the first record at the given level.
 * Other levels are unaffected.
 */
STATIC int				/* success=1, failure=0 */
xfs_btree_firstrec(
	xfs_btree_cur_t		*cur,	/* btree cursor */
	int			level)	/* level to change */
{
	struct xfs_btree_block	*block;	/* generic btree block pointer */
	xfs_buf_t		*bp;	/* buffer containing block */

	/*
	 * Get the block pointer for this level.
	 */
	block = xfs_btree_get_block(cur, level, &bp);
	xfs_btree_check_block(cur, block, level, bp);
	/*
	 * It's empty, there is no such record.
	 */
	if (!block->bb_numrecs)
		return 0;
	/*
	 * Set the ptr value to 1, that's the first record/key.
	 */
	cur->bc_ptrs[level] = 1;
	return 1;
}

/*
 * Change the cursor to point to the last record in the current block
 * at the given level.  Other levels are unaffected.
 */
STATIC int				/* success=1, failure=0 */
xfs_btree_lastrec(
	xfs_btree_cur_t		*cur,	/* btree cursor */
	int			level)	/* level to change */
{
	struct xfs_btree_block	*block;	/* generic btree block pointer */
	xfs_buf_t		*bp;	/* buffer containing block */

	/*
	 * Get the block pointer for this level.
	 */
	block = xfs_btree_get_block(cur, level, &bp);
	xfs_btree_check_block(cur, block, level, bp);
	/*
	 * It's empty, there is no such record.
	 */
	if (!block->bb_numrecs)
		return 0;
	/*
	 * Set the ptr value to numrecs, that's the last record/key.
	 */
	cur->bc_ptrs[level] = be16_to_cpu(block->bb_numrecs);
	return 1;
}

/*
 * Compute first and last byte offsets for the fields given.
 * Interprets the offsets table, which contains struct field offsets.
 */
void
xfs_btree_offsets(
	__int64_t	fields,		/* bitmask of fields */
	const short	*offsets,	/* table of field offsets */
	int		nbits,		/* number of bits to inspect */
	int		*first,		/* output: first byte offset */
	int		*last)		/* output: last byte offset */
{
	int		i;		/* current bit number */
	__int64_t	imask;		/* mask for current bit number */

	ASSERT(fields != 0);
	/*
	 * Find the lowest bit, so the first byte offset.
	 */
	for (i = 0, imask = 1LL; ; i++, imask <<= 1) {
		if (imask & fields) {
			*first = offsets[i];
			break;
		}
	}
	/*
	 * Find the highest bit, so the last byte offset.
	 */
	for (i = nbits - 1, imask = 1LL << i; ; i--, imask >>= 1) {
		if (imask & fields) {
			*last = offsets[i + 1] - 1;
			break;
		}
	}
}

/*
 * Get a buffer for the block, return it read in.
 * Long-form addressing.
 */
int					/* error */
xfs_btree_read_bufl(
	xfs_mount_t	*mp,		/* file system mount point */
	xfs_trans_t	*tp,		/* transaction pointer */
	xfs_fsblock_t	fsbno,		/* file system block number */
	uint		lock,		/* lock flags for read_buf */
	xfs_buf_t	**bpp,		/* buffer for fsbno */
	int		refval)		/* ref count value for buffer */
{
	xfs_buf_t	*bp;		/* return value */
	xfs_daddr_t		d;		/* real disk block address */
	int		error;

	ASSERT(fsbno != NULLFSBLOCK);
	d = XFS_FSB_TO_DADDR(mp, fsbno);
	if ((error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp, d,
			mp->m_bsize, lock, &bp))) {
		return error;
	}
	ASSERT(!bp || !XFS_BUF_GETERROR(bp));
	if (bp != NULL) {
		XFS_BUF_SET_VTYPE_REF(bp, B_FS_MAP, refval);
	}
	*bpp = bp;
	return 0;
}

/*
 * Get a buffer for the block, return it read in.
 * Short-form addressing.
 */
int					/* error */
xfs_btree_read_bufs(
	xfs_mount_t	*mp,		/* file system mount point */
	xfs_trans_t	*tp,		/* transaction pointer */
	xfs_agnumber_t	agno,		/* allocation group number */
	xfs_agblock_t	agbno,		/* allocation group block number */
	uint		lock,		/* lock flags for read_buf */
	xfs_buf_t	**bpp,		/* buffer for agno/agbno */
	int		refval)		/* ref count value for buffer */
{
	xfs_buf_t	*bp;		/* return value */
	xfs_daddr_t	d;		/* real disk block address */
	int		error;

	ASSERT(agno != NULLAGNUMBER);
	ASSERT(agbno != NULLAGBLOCK);
	d = XFS_AGB_TO_DADDR(mp, agno, agbno);
	if ((error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp, d,
					mp->m_bsize, lock, &bp))) {
		return error;
	}
	ASSERT(!bp || !XFS_BUF_GETERROR(bp));
	if (bp != NULL) {
		switch (refval) {
		case XFS_ALLOC_BTREE_REF:
			XFS_BUF_SET_VTYPE_REF(bp, B_FS_MAP, refval);
			break;
		case XFS_INO_BTREE_REF:
			XFS_BUF_SET_VTYPE_REF(bp, B_FS_INOMAP, refval);
			break;
		}
	}
	*bpp = bp;
	return 0;
}

/*
 * Read-ahead the block, don't wait for it, don't return a buffer.
 * Long-form addressing.
 */
/* ARGSUSED */
void
xfs_btree_reada_bufl(
	xfs_mount_t	*mp,		/* file system mount point */
	xfs_fsblock_t	fsbno,		/* file system block number */
	xfs_extlen_t	count)		/* count of filesystem blocks */
{
	xfs_daddr_t		d;

	ASSERT(fsbno != NULLFSBLOCK);
	d = XFS_FSB_TO_DADDR(mp, fsbno);
	xfs_baread(mp->m_ddev_targp, d, mp->m_bsize * count);
}

/*
 * Read-ahead the block, don't wait for it, don't return a buffer.
 * Short-form addressing.
 */
/* ARGSUSED */
void
xfs_btree_reada_bufs(
	xfs_mount_t	*mp,		/* file system mount point */
	xfs_agnumber_t	agno,		/* allocation group number */
	xfs_agblock_t	agbno,		/* allocation group block number */
	xfs_extlen_t	count)		/* count of filesystem blocks */
{
	xfs_daddr_t		d;

	ASSERT(agno != NULLAGNUMBER);
	ASSERT(agbno != NULLAGBLOCK);
	d = XFS_AGB_TO_DADDR(mp, agno, agbno);
	xfs_baread(mp->m_ddev_targp, d, mp->m_bsize * count);
}

STATIC int
xfs_btree_readahead_lblock(
	struct xfs_btree_cur	*cur,
	int			lr,
	struct xfs_btree_block	*block)
{
	int			rval = 0;
	xfs_dfsbno_t		left = be64_to_cpu(block->bb_u.l.bb_leftsib);
	xfs_dfsbno_t		right = be64_to_cpu(block->bb_u.l.bb_rightsib);

	if ((lr & XFS_BTCUR_LEFTRA) && left != NULLDFSBNO) {
		xfs_btree_reada_bufl(cur->bc_mp, left, 1);
		rval++;
	}

	if ((lr & XFS_BTCUR_RIGHTRA) && right != NULLDFSBNO) {
		xfs_btree_reada_bufl(cur->bc_mp, right, 1);
		rval++;
	}

	return rval;
}

STATIC int
xfs_btree_readahead_sblock(
	struct xfs_btree_cur	*cur,
	int			lr,
	struct xfs_btree_block *block)
{
	int			rval = 0;
	xfs_agblock_t		left = be32_to_cpu(block->bb_u.s.bb_leftsib);
	xfs_agblock_t		right = be32_to_cpu(block->bb_u.s.bb_rightsib);


	if ((lr & XFS_BTCUR_LEFTRA) && left != NULLAGBLOCK) {
		xfs_btree_reada_bufs(cur->bc_mp, cur->bc_private.a.agno,
				     left, 1);
		rval++;
	}

	if ((lr & XFS_BTCUR_RIGHTRA) && right != NULLAGBLOCK) {
		xfs_btree_reada_bufs(cur->bc_mp, cur->bc_private.a.agno,
				     right, 1);
		rval++;
	}

	return rval;
}

/*
 * Read-ahead btree blocks, at the given level.
 * Bits in lr are set from XFS_BTCUR_{LEFT,RIGHT}RA.
 */
STATIC int
xfs_btree_readahead(
	struct xfs_btree_cur	*cur,		/* btree cursor */
	int			lev,		/* level in btree */
	int			lr)		/* left/right bits */
{
	struct xfs_btree_block	*block;

	/*
	 * No readahead needed if we are at the root level and the
	 * btree root is stored in the inode.
	 */
	if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
	    (lev == cur->bc_nlevels - 1))
		return 0;

	if ((cur->bc_ra[lev] | lr) == cur->bc_ra[lev])
		return 0;

	cur->bc_ra[lev] |= lr;
	block = XFS_BUF_TO_BLOCK(cur->bc_bufs[lev]);

	if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
		return xfs_btree_readahead_lblock(cur, lr, block);
	return xfs_btree_readahead_sblock(cur, lr, block);
}

/*
 * Set the buffer for level "lev" in the cursor to bp, releasing
 * any previous buffer.
 */
void
xfs_btree_setbuf(
	xfs_btree_cur_t		*cur,	/* btree cursor */
	int			lev,	/* level in btree */
	xfs_buf_t		*bp)	/* new buffer to set */
{
	struct xfs_btree_block	*b;	/* btree block */
	xfs_buf_t		*obp;	/* old buffer pointer */

	obp = cur->bc_bufs[lev];
	if (obp)
		xfs_trans_brelse(cur->bc_tp, obp);
	cur->bc_bufs[lev] = bp;
	cur->bc_ra[lev] = 0;
	if (!bp)
		return;
	b = XFS_BUF_TO_BLOCK(bp);
	if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
		if (be64_to_cpu(b->bb_u.l.bb_leftsib) == NULLDFSBNO)
			cur->bc_ra[lev] |= XFS_BTCUR_LEFTRA;
		if (be64_to_cpu(b->bb_u.l.bb_rightsib) == NULLDFSBNO)
			cur->bc_ra[lev] |= XFS_BTCUR_RIGHTRA;
	} else {
		if (be32_to_cpu(b->bb_u.s.bb_leftsib) == NULLAGBLOCK)
			cur->bc_ra[lev] |= XFS_BTCUR_LEFTRA;
		if (be32_to_cpu(b->bb_u.s.bb_rightsib) == NULLAGBLOCK)
			cur->bc_ra[lev] |= XFS_BTCUR_RIGHTRA;
	}
}

STATIC int
xfs_btree_ptr_is_null(
	struct xfs_btree_cur	*cur,
	union xfs_btree_ptr	*ptr)
{
	if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
		return be64_to_cpu(ptr->l) == NULLDFSBNO;
	else
		return be32_to_cpu(ptr->s) == NULLAGBLOCK;
}

STATIC void
xfs_btree_set_ptr_null(
	struct xfs_btree_cur	*cur,
	union xfs_btree_ptr	*ptr)
{
	if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
		ptr->l = cpu_to_be64(NULLDFSBNO);
	else
		ptr->s = cpu_to_be32(NULLAGBLOCK);
}

/*
 * Get/set/init sibling pointers
 */
STATIC void
xfs_btree_get_sibling(
	struct xfs_btree_cur	*cur,
	struct xfs_btree_block	*block,
	union xfs_btree_ptr	*ptr,
	int			lr)
{
	ASSERT(lr == XFS_BB_LEFTSIB || lr == XFS_BB_RIGHTSIB);

	if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
		if (lr == XFS_BB_RIGHTSIB)
			ptr->l = block->bb_u.l.bb_rightsib;
		else
			ptr->l = block->bb_u.l.bb_leftsib;
	} else {
		if (lr == XFS_BB_RIGHTSIB)
			ptr->s = block->bb_u.s.bb_rightsib;
		else
			ptr->s = block->bb_u.s.bb_leftsib;
	}
}

STATIC void
xfs_btree_set_sibling(
	struct xfs_btree_cur	*cur,
	struct xfs_btree_block	*block,
	union xfs_btree_ptr	*ptr,
	int			lr)
{
	ASSERT(lr == XFS_BB_LEFTSIB || lr == XFS_BB_RIGHTSIB);

	if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
		if (lr == XFS_BB_RIGHTSIB)
			block->bb_u.l.bb_rightsib = ptr->l;
		else
			block->bb_u.l.bb_leftsib = ptr->l;
	} else {
		if (lr == XFS_BB_RIGHTSIB)
			block->bb_u.s.bb_rightsib = ptr->s;
		else
			block->bb_u.s.bb_leftsib = ptr->s;
	}
}

STATIC void
xfs_btree_init_block(
	struct xfs_btree_cur	*cur,
	int			level,
	int			numrecs,
	struct xfs_btree_block	*new)	/* new block */
{
	new->bb_magic = cpu_to_be32(xfs_magics[cur->bc_btnum]);
	new->bb_level = cpu_to_be16(level);
	new->bb_numrecs = cpu_to_be16(numrecs);

	if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
		new->bb_u.l.bb_leftsib = cpu_to_be64(NULLDFSBNO);
		new->bb_u.l.bb_rightsib = cpu_to_be64(NULLDFSBNO);
	} else {
		new->bb_u.s.bb_leftsib = cpu_to_be32(NULLAGBLOCK);
		new->bb_u.s.bb_rightsib = cpu_to_be32(NULLAGBLOCK);
	}
}

/*
 * Return true if ptr is the last record in the btree and
 * we need to track updateѕ to this record.  The decision
 * will be further refined in the update_lastrec method.
 */
STATIC int
xfs_btree_is_lastrec(
	struct xfs_btree_cur	*cur,
	struct xfs_btree_block	*block,
	int			level)
{
	union xfs_btree_ptr	ptr;

	if (level > 0)
		return 0;
	if (!(cur->bc_flags & XFS_BTREE_LASTREC_UPDATE))
		return 0;

	xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
	if (!xfs_btree_ptr_is_null(cur, &ptr))
		return 0;
	return 1;
}

STATIC void
xfs_btree_buf_to_ptr(
	struct xfs_btree_cur	*cur,
	struct xfs_buf		*bp,
	union xfs_btree_ptr	*ptr)
{
	if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
		ptr->l = cpu_to_be64(XFS_DADDR_TO_FSB(cur->bc_mp,
					XFS_BUF_ADDR(bp)));
	else {
		ptr->s = cpu_to_be32(xfs_daddr_to_agbno(cur->bc_mp,
					XFS_BUF_ADDR(bp)));
	}
}

STATIC xfs_daddr_t
xfs_btree_ptr_to_daddr(
	struct xfs_btree_cur	*cur,
	union xfs_btree_ptr	*ptr)
{
	if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
		ASSERT(be64_to_cpu(ptr->l) != NULLDFSBNO);

		return XFS_FSB_TO_DADDR(cur->bc_mp, be64_to_cpu(ptr->l));
	} else {
		ASSERT(cur->bc_private.a.agno != NULLAGNUMBER);
		ASSERT(be32_to_cpu(ptr->s) != NULLAGBLOCK);

		return XFS_AGB_TO_DADDR(cur->bc_mp, cur->bc_private.a.agno,
					be32_to_cpu(ptr->s));
	}
}

STATIC void
xfs_btree_set_refs(
	struct xfs_btree_cur	*cur,
	struct xfs_buf		*bp)
{
	switch (cur->bc_btnum) {
	case XFS_BTNUM_BNO:
	case XFS_BTNUM_CNT:
		XFS_BUF_SET_VTYPE_REF(*bpp, B_FS_MAP, XFS_ALLOC_BTREE_REF);
		break;
	case XFS_BTNUM_INO:
		XFS_BUF_SET_VTYPE_REF(*bpp, B_FS_INOMAP, XFS_INO_BTREE_REF);
		break;
	case XFS_BTNUM_BMAP:
		XFS_BUF_SET_VTYPE_REF(*bpp, B_FS_MAP, XFS_BMAP_BTREE_REF);
		break;
	default:
		ASSERT(0);
	}
}

STATIC int
xfs_btree_get_buf_block(
	struct xfs_btree_cur	*cur,
	union xfs_btree_ptr	*ptr,
	int			flags,
	struct xfs_btree_block	**block,
	struct xfs_buf		**bpp)
{
	struct xfs_mount	*mp = cur->bc_mp;
	xfs_daddr_t		d;

	/* need to sort out how callers deal with failures first */
	ASSERT(!(flags & XFS_BUF_TRYLOCK));

	d = xfs_btree_ptr_to_daddr(cur, ptr);
	*bpp = xfs_trans_get_buf(cur->bc_tp, mp->m_ddev_targp, d,
				 mp->m_bsize, flags);

	ASSERT(*bpp);
	ASSERT(!XFS_BUF_GETERROR(*bpp));

	*block = XFS_BUF_TO_BLOCK(*bpp);
	return 0;
}

/*
 * Read in the buffer at the given ptr and return the buffer and
 * the block pointer within the buffer.
 */
STATIC int
xfs_btree_read_buf_block(
	struct xfs_btree_cur	*cur,
	union xfs_btree_ptr	*ptr,
	int			level,
	int			flags,
	struct xfs_btree_block	**block,
	struct xfs_buf		**bpp)
{
	struct xfs_mount	*mp = cur->bc_mp;
	xfs_daddr_t		d;
	int			error;

	/* need to sort out how callers deal with failures first */
	ASSERT(!(flags & XFS_BUF_TRYLOCK));

	d = xfs_btree_ptr_to_daddr(cur, ptr);
	error = xfs_trans_read_buf(mp, cur->bc_tp, mp->m_ddev_targp, d,
				   mp->m_bsize, flags, bpp);
	if (error)
		return error;

	ASSERT(*bpp != NULL);
	ASSERT(!XFS_BUF_GETERROR(*bpp));

	xfs_btree_set_refs(cur, *bpp);
	*block = XFS_BUF_TO_BLOCK(*bpp);

	error = xfs_btree_check_block(cur, *block, level, *bpp);
	if (error)
		xfs_trans_brelse(cur->bc_tp, *bpp);
	return error;
}

/*
 * Copy keys from one btree block to another.
 */
STATIC void
xfs_btree_copy_keys(
	struct xfs_btree_cur	*cur,
	union xfs_btree_key	*dst_key,
	union xfs_btree_key	*src_key,
	int			numkeys)
{
	ASSERT(numkeys >= 0);
	memcpy(dst_key, src_key, numkeys * cur->bc_ops->key_len);
}

/*
 * Copy records from one btree block to another.
 */
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)
{
	ASSERT(numrecs >= 0);
	memcpy(dst_rec, src_rec, numrecs * cur->bc_ops->rec_len);
}

/*
 * Copy block pointers from one btree block to another.
 */
STATIC void
xfs_btree_copy_ptrs(
	struct xfs_btree_cur	*cur,
	union xfs_btree_ptr	*dst_ptr,
	union xfs_btree_ptr	*src_ptr,
	int			numptrs)
{
	ASSERT(numptrs >= 0);
	memcpy(dst_ptr, src_ptr, numptrs * xfs_btree_ptr_len(cur));
}

/*
 * Shift keys one index left/right inside a single btree block.
 */
STATIC void
xfs_btree_shift_keys(
	struct xfs_btree_cur	*cur,
	union xfs_btree_key	*key,
	int			dir,
	int			numkeys)
{
	char			*dst_key;

	ASSERT(numkeys >= 0);
	ASSERT(dir == 1 || dir == -1);

	dst_key = (char *)key + (dir * cur->bc_ops->key_len);
	memmove(dst_key, key, numkeys * cur->bc_ops->key_len);
}

/*
 * Shift records one index left/right inside a single btree block.
 */
STATIC void
xfs_btree_shift_recs(
	struct xfs_btree_cur	*cur,
	union xfs_btree_rec	*rec,
	int			dir,
	int			numrecs)
{
	char			*dst_rec;

	ASSERT(numrecs >= 0);
	ASSERT(dir == 1 || dir == -1);

	dst_rec = (char *)rec + (dir * cur->bc_ops->rec_len);
	memmove(dst_rec, rec, numrecs * cur->bc_ops->rec_len);
}

/*
 * Shift block pointers one index left/right inside a single btree block.
 */
STATIC void
xfs_btree_shift_ptrs(
	struct xfs_btree_cur	*cur,
	union xfs_btree_ptr	*ptr,
	int			dir,
	int			numptrs)
{
	char			*dst_ptr;

	ASSERT(numptrs >= 0);
	ASSERT(dir == 1 || dir == -1);

	dst_ptr = (char *)ptr + (dir * xfs_btree_ptr_len(cur));
	memmove(dst_ptr, ptr, numptrs * xfs_btree_ptr_len(cur));
}

/*
 * Log key values from the btree block.
 */
STATIC void
xfs_btree_log_keys(
	struct xfs_btree_cur	*cur,
	struct xfs_buf		*bp,
	int			first,
	int			last)
{
	XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
	XFS_BTREE_TRACE_ARGBII(cur, bp, first, last);

	if (bp) {
		xfs_trans_log_buf(cur->bc_tp, bp,
				  xfs_btree_key_offset(cur, first),
				  xfs_btree_key_offset(cur, last + 1) - 1);
	} else {
		xfs_trans_log_inode(cur->bc_tp, cur->bc_private.b.ip,
				xfs_ilog_fbroot(cur->bc_private.b.whichfork));
	}

	XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
}

/*
 * Log record values from the btree block.
 */
void
xfs_btree_log_recs(
	struct xfs_btree_cur	*cur,
	struct xfs_buf		*bp,
	int			first,
	int			last)
{
	XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
	XFS_BTREE_TRACE_ARGBII(cur, bp, first, last);

	xfs_trans_log_buf(cur->bc_tp, bp,
			  xfs_btree_rec_offset(cur, first),
			  xfs_btree_rec_offset(cur, last + 1) - 1);

	XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
}

/*
 * Log block pointer fields from a btree block (nonleaf).
 */
STATIC void
xfs_btree_log_ptrs(
	struct xfs_btree_cur	*cur,	/* btree cursor */
	struct xfs_buf		*bp,	/* buffer containing btree block */
	int			first,	/* index of first pointer to log */
	int			last)	/* index of last pointer to log */
{
	XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
	XFS_BTREE_TRACE_ARGBII(cur, bp, first, last);

	if (bp) {
		struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
		int			level = xfs_btree_get_level(block);

		xfs_trans_log_buf(cur->bc_tp, bp,
				xfs_btree_ptr_offset(cur, first, level),
				xfs_btree_ptr_offset(cur, last + 1, level) - 1);
	} else {
		xfs_trans_log_inode(cur->bc_tp, cur->bc_private.b.ip,
			xfs_ilog_fbroot(cur->bc_private.b.whichfork));
	}

	XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
}

/*
 * Log fields from a btree block header.
 */
void
xfs_btree_log_block(
	struct xfs_btree_cur	*cur,	/* btree cursor */
	struct xfs_buf		*bp,	/* buffer containing btree block */
	int			fields)	/* mask of fields: XFS_BB_... */
{
	int			first;	/* first byte offset logged */
	int			last;	/* last byte offset logged */
	static const short	soffsets[] = {	/* table of offsets (short) */
		offsetof(struct xfs_btree_block, bb_magic),
		offsetof(struct xfs_btree_block, bb_level),
		offsetof(struct xfs_btree_block, bb_numrecs),
		offsetof(struct xfs_btree_block, bb_u.s.bb_leftsib),
		offsetof(struct xfs_btree_block, bb_u.s.bb_rightsib),
		XFS_BTREE_SBLOCK_LEN
	};
	static const short	loffsets[] = {	/* table of offsets (long) */
		offsetof(struct xfs_btree_block, bb_magic),
		offsetof(struct xfs_btree_block, bb_level),
		offsetof(struct xfs_btree_block, bb_numrecs),
		offsetof(struct xfs_btree_block, bb_u.l.bb_leftsib),
		offsetof(struct xfs_btree_block, bb_u.l.bb_rightsib),
		XFS_BTREE_LBLOCK_LEN
	};

	XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
	XFS_BTREE_TRACE_ARGBI(cur, bp, fields);

	if (bp) {
		xfs_btree_offsets(fields,
				  (cur->bc_flags & XFS_BTREE_LONG_PTRS) ?
					loffsets : soffsets,
				  XFS_BB_NUM_BITS, &first, &last);
		xfs_trans_log_buf(cur->bc_tp, bp, first, last);
	} else {
		xfs_trans_log_inode(cur->bc_tp, cur->bc_private.b.ip,
			xfs_ilog_fbroot(cur->bc_private.b.whichfork));
	}

	XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
}

/*
 * Increment cursor by one record at the level.
 * For nonzero levels the leaf-ward information is untouched.
 */
int						/* error */
xfs_btree_increment(
	struct xfs_btree_cur	*cur,
	int			level,
	int			*stat)		/* success/failure */
{
	struct xfs_btree_block	*block;
	union xfs_btree_ptr	ptr;
	struct xfs_buf		*bp;
	int			error;		/* error return value */
	int			lev;

	XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
	XFS_BTREE_TRACE_ARGI(cur, level);

	ASSERT(level < cur->bc_nlevels);

	/* Read-ahead to the right at this level. */
	xfs_btree_readahead(cur, level, XFS_BTCUR_RIGHTRA);

	/* Get a pointer to the btree block. */
	block = xfs_btree_get_block(cur, level, &bp);

#ifdef DEBUG
	error = xfs_btree_check_block(cur, block, level, bp);
	if (error)
		goto error0;
#endif

	/* We're done if we remain in the block after the increment. */
	if (++cur->bc_ptrs[level] <= xfs_btree_get_numrecs(block))
		goto out1;

	/* Fail if we just went off the right edge of the tree. */
	xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
	if (xfs_btree_ptr_is_null(cur, &ptr))
		goto out0;

	XFS_BTREE_STATS_INC(cur, increment);

	/*
	 * March up the tree incrementing pointers.
	 * Stop when we don't go off the right edge of a block.
	 */
	for (lev = level + 1; lev < cur->bc_nlevels; lev++) {
		block = xfs_btree_get_block(cur, lev, &bp);

#ifdef DEBUG
		error = xfs_btree_check_block(cur, block, lev, bp);
		if (error)
			goto error0;
#endif

		if (++cur->bc_ptrs[lev] <= xfs_btree_get_numrecs(block))
			break;

		/* Read-ahead the right block for the next loop. */
		xfs_btree_readahead(cur, lev, XFS_BTCUR_RIGHTRA);
	}

	/*
	 * If we went off the root then we are either seriously
	 * confused or have the tree root in an inode.
	 */
	if (lev == cur->bc_nlevels) {
		if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE)
			goto out0;
		ASSERT(0);
		error = EFSCORRUPTED;
		goto error0;
	}
	ASSERT(lev < cur->bc_nlevels);

	/*
	 * Now walk back down the tree, fixing up the cursor's buffer
	 * pointers and key numbers.
	 */
	for (block = xfs_btree_get_block(cur, lev, &bp); lev > level; ) {
		union xfs_btree_ptr	*ptrp;

		ptrp = xfs_btree_ptr_addr(cur, cur->bc_ptrs[lev], block);
		error = xfs_btree_read_buf_block(cur, ptrp, --lev,
							0, &block, &bp);
		if (error)
			goto error0;

		xfs_btree_setbuf(cur, lev, bp);
		cur->bc_ptrs[lev] = 1;
	}
out1:
	XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
	*stat = 1;
	return 0;

out0:
	XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
	*stat = 0;
	return 0;

error0:
	XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
	return error;
}

/*
 * Decrement cursor by one record at the level.
 * For nonzero levels the leaf-ward information is untouched.
 */
int						/* error */
xfs_btree_decrement(
	struct xfs_btree_cur	*cur,
	int			level,
	int			*stat)		/* success/failure */
{
	struct xfs_btree_block	*block;
	xfs_buf_t		*bp;
	int			error;		/* error return value */
	int			lev;
	union xfs_btree_ptr	ptr;

	XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
	XFS_BTREE_TRACE_ARGI(cur, level);

	ASSERT(level < cur->bc_nlevels);

	/* Read-ahead to the left at this level. */
	xfs_btree_readahead(cur, level, XFS_BTCUR_LEFTRA);

	/* We're done if we remain in the block after the decrement. */
	if (--cur->bc_ptrs[level] > 0)
		goto out1;

	/* Get a pointer to the btree block. */
	block = xfs_btree_get_block(cur, level, &bp);

#ifdef DEBUG
	error = xfs_btree_check_block(cur, block, level, bp);
	if (error)
		goto error0;
#endif

	/* Fail if we just went off the left edge of the tree. */
	xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_LEFTSIB);
	if (xfs_btree_ptr_is_null(cur, &ptr))
		goto out0;

	XFS_BTREE_STATS_INC(cur, decrement);

	/*
	 * March up the tree decrementing pointers.
	 * Stop when we don't go off the left edge of a block.
	 */
	for (lev = level + 1; lev < cur->bc_nlevels; lev++) {
		if (--cur->bc_ptrs[lev] > 0)
			break;
		/* Read-ahead the left block for the next loop. */
		xfs_btree_readahead(cur, lev, XFS_BTCUR_LEFTRA);
	}

	/*
	 * If we went off the root then we are seriously confused.
	 * or the root of the tree is in an inode.
	 */
	if (lev == cur->bc_nlevels) {
		if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE)
			goto out0;
		ASSERT(0);
		error = EFSCORRUPTED;
		goto error0;
	}
	ASSERT(lev < cur->bc_nlevels);

	/*
	 * Now walk back down the tree, fixing up the cursor's buffer
	 * pointers and key numbers.
	 */
	for (block = xfs_btree_get_block(cur, lev, &bp); lev > level; ) {
		union xfs_btree_ptr	*ptrp;

		ptrp = xfs_btree_ptr_addr(cur, cur->bc_ptrs[lev], block);
		error = xfs_btree_read_buf_block(cur, ptrp, --lev,
							0, &block, &bp);
		if (error)
			goto error0;
		xfs_btree_setbuf(cur, lev, bp);
		cur->bc_ptrs[lev] = xfs_btree_get_numrecs(block);
	}
out1:
	XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
	*stat = 1;
	return 0;

out0:
	XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
	*stat = 0;
	return 0;

error0:
	XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
	return error;
}

STATIC int
xfs_btree_lookup_get_block(
	struct xfs_btree_cur	*cur,	/* btree cursor */
	int			level,	/* level in the btree */
	union xfs_btree_ptr	*pp,	/* ptr to btree block */
	struct xfs_btree_block	**blkp) /* return btree block */
{
	struct xfs_buf		*bp;	/* buffer pointer for btree block */
	int			error = 0;

	/* special case the root block if in an inode */
	if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
	    (level == cur->bc_nlevels - 1)) {
		*blkp = xfs_btree_get_iroot(cur);
		return 0;
	}

	/*
	 * If the old buffer at this level for the disk address we are
	 * looking for re-use it.
	 *
	 * Otherwise throw it away and get a new one.
	 */
	bp = cur->bc_bufs[level];
	if (bp && XFS_BUF_ADDR(bp) == xfs_btree_ptr_to_daddr(cur, pp)) {
		*blkp = XFS_BUF_TO_BLOCK(bp);
		return 0;
	}

	error = xfs_btree_read_buf_block(cur, pp, level, 0, blkp, &bp);
	if (error)
		return error;

	xfs_btree_setbuf(cur, level, bp);
	return 0;
}

/*
 * Get current search key.  For level 0 we don't actually have a key
 * structure so we make one up from the record.  For all other levels
 * we just return the right key.
 */
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)
{
	if (level == 0) {
		cur->bc_ops->init_key_from_rec(kp,
				xfs_btree_rec_addr(cur, keyno, block));
		return kp;
	}

	return xfs_btree_key_addr(cur, keyno, block);
}

/*
 * Lookup the record.  The cursor is made to point to it, based on dir.
 * Return 0 if can't find any such record, 1 for success.
 */
int					/* error */
xfs_btree_lookup(
	struct xfs_btree_cur	*cur,	/* btree cursor */
	xfs_lookup_t		dir,	/* <=, ==, or >= */
	int			*stat)	/* success/failure */
{
	struct xfs_btree_block	*block;	/* current btree block */
	__int64_t		diff;	/* difference for the current key */
	int			error;	/* error return value */
	int			keyno;	/* current key number */
	int			level;	/* level in the btree */
	union xfs_btree_ptr	*pp;	/* ptr to btree block */
	union xfs_btree_ptr	ptr;	/* ptr to btree block */

	XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
	XFS_BTREE_TRACE_ARGI(cur, dir);

	XFS_BTREE_STATS_INC(cur, lookup);

	block = NULL;
	keyno = 0;

	/* initialise start pointer from cursor */
	cur->bc_ops->init_ptr_from_cur(cur, &ptr);
	pp = &ptr;

	/*
	 * Iterate over each level in the btree, starting at the root.
	 * For each level above the leaves, find the key we need, based
	 * on the lookup record, then follow the corresponding block
	 * pointer down to the next level.
	 */
	for (level = cur->bc_nlevels - 1, diff = 1; level >= 0; level--) {
		/* Get the block we need to do the lookup on. */
		error = xfs_btree_lookup_get_block(cur, level, pp, &block);
		if (error)
			goto error0;

		if (diff == 0) {
			/*
			 * If we already had a key match at a higher level, we
			 * know we need to use the first entry in this block.
			 */
			keyno = 1;
		} else {
			/* Otherwise search this block. Do a binary search. */

			int	high;	/* high entry number */
			int	low;	/* low entry number */

			/* Set low and high entry numbers, 1-based. */
			low = 1;
			high = xfs_btree_get_numrecs(block);
			if (!high) {
				/* Block is empty, must be an empty leaf. */
				ASSERT(level == 0 && cur->bc_nlevels == 1);

				cur->bc_ptrs[0] = dir != XFS_LOOKUP_LE;
				XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
				*stat = 0;
				return 0;
			}

			/* Binary search the block. */
			while (low <= high) {
				union xfs_btree_key	key;
				union xfs_btree_key	*kp;

				XFS_BTREE_STATS_INC(cur, compare);

				/* keyno is average of low and high. */
				keyno = (low + high) >> 1;

				/* Get current search key */
				kp = xfs_lookup_get_search_key(cur, level,
						keyno, block, &key);

				/*
				 * Compute difference to get next direction:
				 *  - less than, move right
				 *  - greater than, move left
				 *  - equal, we're done
				 */
				diff = cur->bc_ops->key_diff(cur, kp);
				if (diff < 0)
					low = keyno + 1;
				else if (diff > 0)
					high = keyno - 1;
				else
					break;
			}
		}

		/*
		 * If there are more levels, set up for the next level
		 * by getting the block number and filling in the cursor.
		 */
		if (level > 0) {
			/*
			 * If we moved left, need the previous key number,
			 * unless there isn't one.
			 */
			if (diff > 0 && --keyno < 1)
				keyno = 1;
			pp = xfs_btree_ptr_addr(cur, keyno, block);

#ifdef DEBUG
			error = xfs_btree_check_ptr(cur, pp, 0, level);
			if (error)
				goto error0;
#endif
			cur->bc_ptrs[level] = keyno;
		}
	}

	/* Done with the search. See if we need to adjust the results. */
	if (dir != XFS_LOOKUP_LE && diff < 0) {
		keyno++;
		/*
		 * If ge search and we went off the end of the block, but it's
		 * not the last block, we're in the wrong block.
		 */
		xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
		if (dir == XFS_LOOKUP_GE &&
		    keyno > xfs_btree_get_numrecs(block) &&
		    !xfs_btree_ptr_is_null(cur, &ptr)) {
			int	i;

			cur->bc_ptrs[0] = keyno;
			error = xfs_btree_increment(cur, 0, &i);
			if (error)
				goto error0;
			XFS_WANT_CORRUPTED_RETURN(i == 1);
			XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
			*stat = 1;
			return 0;
		}
	} else if (dir == XFS_LOOKUP_LE && diff > 0)
		keyno--;
	cur->bc_ptrs[0] = keyno;

	/* Return if we succeeded or not. */
	if (keyno == 0 || keyno > xfs_btree_get_numrecs(block))
		*stat = 0;
	else if (dir != XFS_LOOKUP_EQ || diff == 0)
		*stat = 1;
	else
		*stat = 0;
	XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
	return 0;

error0:
	XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
	return error;
}

/*
 * Update keys at all levels from here to the root along the cursor's path.
 */
STATIC int
xfs_btree_updkey(
	struct xfs_btree_cur	*cur,
	union xfs_btree_key	*keyp,
	int			level)
{
	struct xfs_btree_block	*block;
	struct xfs_buf		*bp;
	union xfs_btree_key	*kp;
	int			ptr;

	XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
	XFS_BTREE_TRACE_ARGIK(cur, level, keyp);

	ASSERT(!(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) || level >= 1);

	/*
	 * Go up the tree from this level toward the root.
	 * At each level, update the key value to the value input.
	 * Stop when we reach a level where the cursor isn't pointing
	 * at the first entry in the block.
	 */
	for (ptr = 1; ptr == 1 && level < cur->bc_nlevels; level++) {
#ifdef DEBUG
		int		error;
#endif
		block = xfs_btree_get_block(cur, level, &bp);
#ifdef DEBUG
		error = xfs_btree_check_block(cur, block, level, bp);
		if (error) {
			XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
			return error;
		}
#endif
		ptr = cur->bc_ptrs[level];
		kp = xfs_btree_key_addr(cur, ptr, block);
		xfs_btree_copy_keys(cur, kp, keyp, 1);
		xfs_btree_log_keys(cur, bp, ptr, ptr);
	}

	XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
	return 0;
}

/*
 * Update the record referred to by cur to the value in the
 * given record. This either works (return 0) or gets an
 * EFSCORRUPTED error.
 */
int
xfs_btree_update(
	struct xfs_btree_cur	*cur,
	union xfs_btree_rec	*rec)
{
	struct xfs_btree_block	*block;
	struct xfs_buf		*bp;
	int			error;
	int			ptr;
	union xfs_btree_rec	*rp;

	XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
	XFS_BTREE_TRACE_ARGR(cur, rec);

	/* Pick up the current block. */
	block = xfs_btree_get_block(cur, 0, &bp);

#ifdef DEBUG
	error = xfs_btree_check_block(cur, block, 0, bp);
	if (error)
		goto error0;
#endif
	/* Get the address of the rec to be updated. */
	ptr = cur->bc_ptrs[0];
	rp = xfs_btree_rec_addr(cur, ptr, block);

	/* Fill in the new contents and log them. */
	xfs_btree_copy_recs(cur, rp, rec, 1);
	xfs_btree_log_recs(cur, bp, ptr, ptr);

	/*
	 * If we are tracking the last record in the tree and
	 * we are at the far right edge of the tree, update it.
	 */
	if (xfs_btree_is_lastrec(cur, block, 0)) {
		cur->bc_ops->update_lastrec(cur, block, rec,
					    ptr, LASTREC_UPDATE);
	}

	/* Updating first rec in leaf. Pass new key value up to our parent. */
	if (ptr == 1) {
		union xfs_btree_key	key;

		cur->bc_ops->init_key_from_rec(&key, rec);
		error = xfs_btree_updkey(cur, &key, 1);
		if (error)
			goto error0;
	}

	XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
	return 0;

error0:
	XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
	return error;
}

/*
 * Move 1 record left from cur/level if possible.
 * Update cur to reflect the new path.
 */
STATIC int					/* error */
xfs_btree_lshift(
	struct xfs_btree_cur	*cur,
	int			level,
	int			*stat)		/* success/failure */
{
	union xfs_btree_key	key;		/* btree key */
	struct xfs_buf		*lbp;		/* left buffer pointer */
	struct xfs_btree_block	*left;		/* left btree block */
	int			lrecs;		/* left record count */
	struct xfs_buf		*rbp;		/* right buffer pointer */
	struct xfs_btree_block	*right;		/* right btree block */
	int			rrecs;		/* right record count */
	union xfs_btree_ptr	lptr;		/* left btree pointer */
	union xfs_btree_key	*rkp = NULL;	/* right btree key */
	union xfs_btree_ptr	*rpp = NULL;	/* right address pointer */
	union xfs_btree_rec	*rrp = NULL;	/* right record pointer */
	int			error;		/* error return value */

	XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
	XFS_BTREE_TRACE_ARGI(cur, level);

	if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
	    level == cur->bc_nlevels - 1)
		goto out0;

	/* Set up variables for this block as "right". */
	right = xfs_btree_get_block(cur, level, &rbp);

#ifdef DEBUG
	error = xfs_btree_check_block(cur, right, level, rbp);
	if (error)
		goto error0;
#endif

	/* If we've got no left sibling then we can't shift an entry left. */
	xfs_btree_get_sibling(cur, right, &lptr, XFS_BB_LEFTSIB);
	if (xfs_btree_ptr_is_null(cur, &lptr))
		goto out0;

	/*
	 * If the cursor entry is the one that would be moved, don't
	 * do it... it's too complicated.
	 */
	if (cur->bc_ptrs[level] <= 1)
		goto out0;

	/* Set up the left neighbor as "left". */
	error = xfs_btree_read_buf_block(cur, &lptr, level, 0, &left, &lbp);
	if (error)
		goto error0;

	/* If it's full, it can't take another entry. */
	lrecs = xfs_btree_get_numrecs(left);
	if (lrecs == cur->bc_ops->get_maxrecs(cur, level))
		goto out0;

	rrecs = xfs_btree_get_numrecs(right);

	/*
	 * We add one entry to the left side and remove one for the right side.
	 * Account for it here, the changes will be updated on disk and logged
	 * later.
	 */
	lrecs++;
	rrecs--;

	XFS_BTREE_STATS_INC(cur, lshift);
	XFS_BTREE_STATS_ADD(cur, moves, 1);

	/*
	 * If non-leaf, copy a key and a ptr to the left block.
	 * Log the changes to the left block.
	 */
	if (level > 0) {
		/* It's a non-leaf.  Move keys and pointers. */
		union xfs_btree_key	*lkp;	/* left btree key */
		union xfs_btree_ptr	*lpp;	/* left address pointer */

		lkp = xfs_btree_key_addr(cur, lrecs, left);
		rkp = xfs_btree_key_addr(cur, 1, right);

		lpp = xfs_btree_ptr_addr(cur, lrecs, left);
		rpp = xfs_btree_ptr_addr(cur, 1, right);
#ifdef DEBUG
		error = xfs_btree_check_ptr(cur, rpp, 0, level);
		if (error)
			goto error0;
#endif
		xfs_btree_copy_keys(cur, lkp, rkp, 1);
		xfs_btree_copy_ptrs(cur, lpp, rpp, 1);

		xfs_btree_log_keys(cur, lbp, lrecs, lrecs);
		xfs_btree_log_ptrs(cur, lbp, lrecs, lrecs);

		ASSERT(cur->bc_ops->keys_inorder(cur,
			xfs_btree_key_addr(cur, lrecs - 1, left), lkp));
	} else {
		/* It's a leaf.  Move records.  */
		union xfs_btree_rec	*lrp;	/* left record pointer */

		lrp = xfs_btree_rec_addr(cur, lrecs, left);
		rrp = xfs_btree_rec_addr(cur, 1, right);

		xfs_btree_copy_recs(cur, lrp, rrp, 1);
		xfs_btree_log_recs(cur, lbp, lrecs, lrecs);

		ASSERT(cur->bc_ops->recs_inorder(cur,
			xfs_btree_rec_addr(cur, lrecs - 1, left), lrp));
	}

	xfs_btree_set_numrecs(left, lrecs);
	xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS);

	xfs_btree_set_numrecs(right, rrecs);
	xfs_btree_log_block(cur, rbp, XFS_BB_NUMRECS);

	/*
	 * Slide the contents of right down one entry.
	 */
	XFS_BTREE_STATS_ADD(cur, moves, rrecs - 1);
	if (level > 0) {
		/* It's a nonleaf. operate on keys and ptrs */
#ifdef DEBUG
		int			i;		/* loop index */

		for (i = 0; i < rrecs; i++) {
			error = xfs_btree_check_ptr(cur, rpp, i + 1, level);
			if (error)
				goto error0;
		}
#endif
		xfs_btree_shift_keys(cur,
				xfs_btree_key_addr(cur, 2, right),
				-1, rrecs);
		xfs_btree_shift_ptrs(cur,
				xfs_btree_ptr_addr(cur, 2, right),
				-1, rrecs);

		xfs_btree_log_keys(cur, rbp, 1, rrecs);
		xfs_btree_log_ptrs(cur, rbp, 1, rrecs);
	} else {
		/* It's a leaf. operate on records */
		xfs_btree_shift_recs(cur,
			xfs_btree_rec_addr(cur, 2, right),
			-1, rrecs);
		xfs_btree_log_recs(cur, rbp, 1, rrecs);

		/*
		 * If it's the first record in the block, we'll need a key
		 * structure to pass up to the next level (updkey).
		 */
		cur->bc_ops->init_key_from_rec(&key,
			xfs_btree_rec_addr(cur, 1, right));
		rkp = &key;
	}

	/* Update the parent key values of right. */
	error = xfs_btree_updkey(cur, rkp, level + 1);
	if (error)
		goto error0;

	/* Slide the cursor value left one. */
	cur->bc_ptrs[level]--;

	XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
	*stat = 1;
	return 0;

out0:
	XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
	*stat = 0;
	return 0;

error0:
	XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
	return error;
}

/*
 * Move 1 record right from cur/level if possible.
 * Update cur to reflect the new path.
 */
STATIC int					/* error */
xfs_btree_rshift(
	struct xfs_btree_cur	*cur,
	int			level,
	int			*stat)		/* success/failure */
{
	union xfs_btree_key	key;		/* btree key */
	struct xfs_buf		*lbp;		/* left buffer pointer */
	struct xfs_btree_block	*left;		/* left btree block */
	struct xfs_buf		*rbp;		/* right buffer pointer */
	struct xfs_btree_block	*right;		/* right btree block */
	struct xfs_btree_cur	*tcur;		/* temporary btree cursor */
	union xfs_btree_ptr	rptr;		/* right block pointer */
	union xfs_btree_key	*rkp;		/* right btree key */
	int			rrecs;		/* right record count */
	int			lrecs;		/* left record count */
	int			error;		/* error return value */
	int			i;		/* loop counter */

	XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
	XFS_BTREE_TRACE_ARGI(cur, level);

	if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
	    (level == cur->bc_nlevels - 1))
		goto out0;

	/* Set up variables for this block as "left". */
	left = xfs_btree_get_block(cur, level, &lbp);

#ifdef DEBUG
	error = xfs_btree_check_block(cur, left, level, lbp);
	if (error)
		goto error0;
#endif

	/* If we've got no right sibling then we can't shift an entry right. */
	xfs_btree_get_sibling(cur, left, &rptr, XFS_BB_RIGHTSIB);
	if (xfs_btree_ptr_is_null(cur, &rptr))
		goto out0;

	/*
	 * If the cursor entry is the one that would be moved, don't
	 * do it... it's too complicated.
	 */
	lrecs = xfs_btree_get_numrecs(left);
	if (cur->bc_ptrs[level] >= lrecs)
		goto out0;

	/* Set up the right neighbor as "right". */
	error = xfs_btree_read_buf_block(cur, &rptr, level, 0, &right, &rbp);
	if (error)
		goto error0;

	/* If it's full, it can't take another entry. */
	rrecs = xfs_btree_get_numrecs(right);
	if (rrecs == cur->bc_ops->get_maxrecs(cur, level))
		goto out0;

	XFS_BTREE_STATS_INC(cur, rshift);
	XFS_BTREE_STATS_ADD(cur, moves, rrecs);

	/*
	 * Make a hole at the start of the right neighbor block, then
	 * copy the last left block entry to the hole.
	 */
	if (level > 0) {
		/* It's a nonleaf. make a hole in the keys and ptrs */
		union xfs_btree_key	*lkp;
		union xfs_btree_ptr	*lpp;
		union xfs_btree_ptr	*rpp;

		lkp = xfs_btree_key_addr(cur, lrecs, left);
		lpp = xfs_btree_ptr_addr(cur, lrecs, left);
		rkp = xfs_btree_key_addr(cur, 1, right);
		rpp = xfs_btree_ptr_addr(cur, 1, right);

#ifdef DEBUG
		for (i = rrecs - 1; i >= 0; i--) {
			error = xfs_btree_check_ptr(cur, rpp, i, level);
			if (error)
				goto error0;
		}
#endif

		xfs_btree_shift_keys(cur, rkp, 1, rrecs);
		xfs_btree_shift_ptrs(cur, rpp, 1, rrecs);

#ifdef DEBUG
		error = xfs_btree_check_ptr(cur, lpp, 0, level);
		if (error)
			goto error0;
#endif

		/* Now put the new data in, and log it. */
		xfs_btree_copy_keys(cur, rkp, lkp, 1);
		xfs_btree_copy_ptrs(cur, rpp, lpp, 1);

		xfs_btree_log_keys(cur, rbp, 1, rrecs + 1);
		xfs_btree_log_ptrs(cur, rbp, 1, rrecs + 1);

		ASSERT(cur->bc_ops->keys_inorder(cur, rkp,
			xfs_btree_key_addr(cur, 2, right)));
	} else {
		/* It's a leaf. make a hole in the records */
		union xfs_btree_rec	*lrp;
		union xfs_btree_rec	*rrp;

		lrp = xfs_btree_rec_addr(cur, lrecs, left);
		rrp = xfs_btree_rec_addr(cur, 1, right);

		xfs_btree_shift_recs(cur, rrp, 1, rrecs);

		/* Now put the new data in, and log it. */
		xfs_btree_copy_recs(cur, rrp, lrp, 1);
		xfs_btree_log_recs(cur, rbp, 1, rrecs + 1);

		cur->bc_ops->init_key_from_rec(&key, rrp);
		rkp = &key;

		ASSERT(cur->bc_ops->recs_inorder(cur, rrp,
			xfs_btree_rec_addr(cur, 2, right)));
	}

	/*
	 * Decrement and log left's numrecs, bump and log right's numrecs.
	 */
	xfs_btree_set_numrecs(left, --lrecs);
	xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS);

	xfs_btree_set_numrecs(right, ++rrecs);
	xfs_btree_log_block(cur, rbp, XFS_BB_NUMRECS);

	/*
	 * Using a temporary cursor, update the parent key values of the
	 * block on the right.
	 */
	error = xfs_btree_dup_cursor(cur, &tcur);
	if (error)
		goto error0;
	i = xfs_btree_lastrec(tcur, level);
	XFS_WANT_CORRUPTED_GOTO(i == 1, error0);

	error = xfs_btree_increment(tcur, level, &i);
	if (error)
		goto error1;

	error = xfs_btree_updkey(tcur, rkp, level + 1);
	if (error)
		goto error1;

	xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);

	XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
	*stat = 1;
	return 0;

out0:
	XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
	*stat = 0;
	return 0;

error0:
	XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
	return error;

error1:
	XFS_BTREE_TRACE_CURSOR(tcur, XBT_ERROR);
	xfs_btree_del_cursor(tcur, XFS_BTREE_ERROR);
	return error;
}

/*
 * Split cur/level block in half.
 * Return new block number and the key to its first
 * record (to be inserted into parent).
 */
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)		/* success/failure */
{
	union xfs_btree_ptr	lptr;		/* left sibling block ptr */
	struct xfs_buf		*lbp;		/* left buffer pointer */
	struct xfs_btree_block	*left;		/* left btree block */
	union xfs_btree_ptr	rptr;		/* right sibling block ptr */
	struct xfs_buf		*rbp;		/* right buffer pointer */
	struct xfs_btree_block	*right;		/* right btree block */
	union xfs_btree_ptr	rrptr;		/* right-right sibling ptr */
	struct xfs_buf		*rrbp;		/* right-right buffer pointer */
	struct xfs_btree_block	*rrblock;	/* right-right btree block */
	int			lrecs;
	int			rrecs;
	int			src_index;
	int			error;		/* error return value */
#ifdef DEBUG
	int			i;
#endif

	XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
	XFS_BTREE_TRACE_ARGIPK(cur, level, *ptrp, key);

	XFS_BTREE_STATS_INC(cur, split);

	/* Set up left block (current one). */
	left = xfs_btree_get_block(cur, level, &lbp);

#ifdef DEBUG
	error = xfs_btree_check_block(cur, left, level, lbp);
	if (error)
		goto error0;
#endif

	xfs_btree_buf_to_ptr(cur, lbp, &lptr);

	/* Allocate the new block. If we can't do it, we're toast. Give up. */
	error = cur->bc_ops->alloc_block(cur, &lptr, &rptr, 1, stat);
	if (error)
		goto error0;
	if (*stat == 0)
		goto out0;
	XFS_BTREE_STATS_INC(cur, alloc);

	/* Set up the new block as "right". */
	error = xfs_btree_get_buf_block(cur, &rptr, 0, &right, &rbp);
	if (error)
		goto error0;

	/* Fill in the btree header for the new right block. */
	xfs_btree_init_block(cur, xfs_btree_get_level(left), 0, right);

	/*
	 * Split the entries between the old and the new block evenly.
	 * Make sure that if there's an odd number of entries now, that
	 * each new block will have the same number of entries.
	 */
	lrecs = xfs_btree_get_numrecs(left);
	rrecs = lrecs / 2;
	if ((lrecs & 1) && cur->bc_ptrs[level] <= rrecs + 1)
		rrecs++;
	src_index = (lrecs - rrecs + 1);

	XFS_BTREE_STATS_ADD(cur, moves, rrecs);

	/*
	 * Copy btree block entries from the left block over to the
	 * new block, the right. Update the right block and log the
	 * changes.
	 */
	if (level > 0) {
		/* It's a non-leaf.  Move keys and pointers. */
		union xfs_btree_key	*lkp;	/* left btree key */
		union xfs_btree_ptr	*lpp;	/* left address pointer */
		union xfs_btree_key	*rkp;	/* right btree key */
		union xfs_btree_ptr	*rpp;	/* right address pointer */

		lkp = xfs_btree_key_addr(cur, src_index, left);
		lpp = xfs_btree_ptr_addr(cur, src_index, left);
		rkp = xfs_btree_key_addr(cur, 1, right);
		rpp = xfs_btree_ptr_addr(cur, 1, right);

#ifdef DEBUG
		for (i = src_index; i < rrecs; i++) {
			error = xfs_btree_check_ptr(cur, lpp, i, level);
			if (error)
				goto error0;
		}
#endif

		xfs_btree_copy_keys(cur, rkp, lkp, rrecs);
		xfs_btree_copy_ptrs(cur, rpp, lpp, rrecs);

		xfs_btree_log_keys(cur, rbp, 1, rrecs);
		xfs_btree_log_ptrs(cur, rbp, 1, rrecs);

		/* Grab the keys to the entries moved to the right block */
		xfs_btree_copy_keys(cur, key, rkp, 1);
	} else {
		/* It's a leaf.  Move records.  */
		union xfs_btree_rec	*lrp;	/* left record pointer */
		union xfs_btree_rec	*rrp;	/* right record pointer */

		lrp = xfs_btree_rec_addr(cur, src_index, left);
		rrp = xfs_btree_rec_addr(cur, 1, right);

		xfs_btree_copy_recs(cur, rrp, lrp, rrecs);
		xfs_btree_log_recs(cur, rbp, 1, rrecs);

		cur->bc_ops->init_key_from_rec(key,
			xfs_btree_rec_addr(cur, 1, right));
	}


	/*
	 * Find the left block number by looking in the buffer.
	 * Adjust numrecs, sibling pointers.
	 */
	xfs_btree_get_sibling(cur, left, &rrptr, XFS_BB_RIGHTSIB);
	xfs_btree_set_sibling(cur, right, &rrptr, XFS_BB_RIGHTSIB);
	xfs_btree_set_sibling(cur, right, &lptr, XFS_BB_LEFTSIB);
	xfs_btree_set_sibling(cur, left, &rptr, XFS_BB_RIGHTSIB);

	lrecs -= rrecs;
	xfs_btree_set_numrecs(left, lrecs);
	xfs_btree_set_numrecs(right, xfs_btree_get_numrecs(right) + rrecs);

	xfs_btree_log_block(cur, rbp, XFS_BB_ALL_BITS);
	xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS | XFS_BB_RIGHTSIB);

	/*
	 * If there's a block to the new block's right, make that block
	 * point back to right instead of to left.
	 */
	if (!xfs_btree_ptr_is_null(cur, &rrptr)) {
		error = xfs_btree_read_buf_block(cur, &rrptr, level,
							0, &rrblock, &rrbp);
		if (error)
			goto error0;
		xfs_btree_set_sibling(cur, rrblock, &rptr, XFS_BB_LEFTSIB);
		xfs_btree_log_block(cur, rrbp, XFS_BB_LEFTSIB);
	}
	/*
	 * If the cursor is really in the right block, move it there.
	 * If it's just pointing past the last entry in left, then we'll
	 * insert there, so don't change anything in that case.
	 */
	if (cur->bc_ptrs[level] > lrecs + 1) {
		xfs_btree_setbuf(cur, level, rbp);
		cur->bc_ptrs[level] -= lrecs;
	}
	/*
	 * If there are more levels, we'll need another cursor which refers
	 * the right block, no matter where this cursor was.
	 */
	if (level + 1 < cur->bc_nlevels) {
		error = xfs_btree_dup_cursor(cur, curp);
		if (error)
			goto error0;
		(*curp)->bc_ptrs[level + 1]++;
	}
	*ptrp = rptr;
	XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
	*stat = 1;
	return 0;
out0:
	XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
	*stat = 0;
	return 0;

error0:
	XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
	return error;
}

/*
 * Copy the old inode root contents into a real block and make the
 * broot point to it.
 */
int						/* error */
xfs_btree_new_iroot(
	struct xfs_btree_cur	*cur,		/* btree cursor */
	int			*logflags,	/* logging flags for inode */
	int			*stat)		/* return status - 0 fail */
{
	struct xfs_buf		*cbp;		/* buffer for cblock */
	struct xfs_btree_block	*block;		/* btree block */
	struct xfs_btree_block	*cblock;	/* child btree block */
	union xfs_btree_key	*ckp;		/* child key pointer */
	union xfs_btree_ptr	*cpp;		/* child ptr pointer */
	union xfs_btree_key	*kp;		/* pointer to btree key */
	union xfs_btree_ptr	*pp;		/* pointer to block addr */
	union xfs_btree_ptr	nptr;		/* new block addr */
	int			level;		/* btree level */
	int			error;		/* error return code */
#ifdef DEBUG
	int			i;		/* loop counter */
#endif

	XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
	XFS_BTREE_STATS_INC(cur, newroot);

	ASSERT(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE);

	level = cur->bc_nlevels - 1;

	block = xfs_btree_get_iroot(cur);
	pp = xfs_btree_ptr_addr(cur, 1, block);

	/* Allocate the new block. If we can't do it, we're toast. Give up. */
	error = cur->bc_ops->alloc_block(cur, pp, &nptr, 1, stat);
	if (error)
		goto error0;
	if (*stat == 0) {
		XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
		return 0;
	}
	XFS_BTREE_STATS_INC(cur, alloc);

	/* Copy the root into a real block. */
	error = xfs_btree_get_buf_block(cur, &nptr, 0, &cblock, &cbp);
	if (error)
		goto error0;

	memcpy(cblock, block, xfs_btree_block_len(cur));

	be16_add_cpu(&block->bb_level, 1);
	xfs_btree_set_numrecs(block, 1);
	cur->bc_nlevels++;
	cur->bc_ptrs[level + 1] = 1;

	kp = xfs_btree_key_addr(cur, 1, block);
	ckp = xfs_btree_key_addr(cur, 1, cblock);
	xfs_btree_copy_keys(cur, ckp, kp, xfs_btree_get_numrecs(cblock));

	cpp = xfs_btree_ptr_addr(cur, 1, cblock);
#ifdef DEBUG
	for (i = 0; i < be16_to_cpu(cblock->bb_numrecs); i++) {
		error = xfs_btree_check_ptr(cur, pp, i, level);
		if (error)
			goto error0;
	}
#endif
	xfs_btree_copy_ptrs(cur, cpp, pp, xfs_btree_get_numrecs(cblock));

#ifdef DEBUG
	error = xfs_btree_check_ptr(cur, &nptr, 0, level);
	if (error)
		goto error0;
#endif
	xfs_btree_copy_ptrs(cur, pp, &nptr, 1);

	xfs_iroot_realloc(cur->bc_private.b.ip,
			  1 - xfs_btree_get_numrecs(cblock),
			  cur->bc_private.b.whichfork);

	xfs_btree_setbuf(cur, level, cbp);

	/*
	 * Do all this logging at the end so that
	 * the root is at the right level.
	 */
	xfs_btree_log_block(cur, cbp, XFS_BB_ALL_BITS);
	xfs_btree_log_keys(cur, cbp, 1, be16_to_cpu(cblock->bb_numrecs));
	xfs_btree_log_ptrs(cur, cbp, 1, be16_to_cpu(cblock->bb_numrecs));

	*logflags |=
		XFS_ILOG_CORE | xfs_ilog_fbroot(cur->bc_private.b.whichfork);
	*stat = 1;
	XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
	return 0;
error0:
	XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
	return error;
}

/*
 * Allocate a new root block, fill it in.
 */
STATIC int				/* error */
xfs_btree_new_root(
	struct xfs_btree_cur	*cur,	/* btree cursor */
	int			*stat)	/* success/failure */
{
	struct xfs_btree_block	*block;	/* one half of the old root block */
	struct xfs_buf		*bp;	/* buffer containing block */
	int			error;	/* error return value */
	struct xfs_buf		*lbp;	/* left buffer pointer */
	struct xfs_btree_block	*left;	/* left btree block */
	struct xfs_buf		*nbp;	/* new (root) buffer */
	struct xfs_btree_block	*new;	/* new (root) btree block */
	int			nptr;	/* new value for key index, 1 or 2 */
	struct xfs_buf		*rbp;	/* right buffer pointer */
	struct xfs_btree_block	*right;	/* right btree block */
	union xfs_btree_ptr	rptr;
	union xfs_btree_ptr	lptr;

	XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
	XFS_BTREE_STATS_INC(cur, newroot);

	/* initialise our start point from the cursor */
	cur->bc_ops->init_ptr_from_cur(cur, &rptr);

	/* Allocate the new block. If we can't do it, we're toast. Give up. */
	error = cur->bc_ops->alloc_block(cur, &rptr, &lptr, 1, stat);
	if (error)
		goto error0;
	if (*stat == 0)
		goto out0;
	XFS_BTREE_STATS_INC(cur, alloc);

	/* Set up the new block. */
	error = xfs_btree_get_buf_block(cur, &lptr, 0, &new, &nbp);
	if (error)
		goto error0;

	/* Set the root in the holding structure  increasing the level by 1. */
	cur->bc_ops->set_root(cur, &lptr, 1);

	/*
	 * At the previous root level there are now two blocks: the old root,
	 * and the new block generated when it was split.  We don't know which
	 * one the cursor is pointing at, so we set up variables "left" and
	 * "right" for each case.
	 */
	block = xfs_btree_get_block(cur, cur->bc_nlevels - 1, &bp);

#ifdef DEBUG
	error = xfs_btree_check_block(cur, block, cur->bc_nlevels - 1, bp);
	if (error)
		goto error0;
#endif

	xfs_btree_get_sibling(cur, block, &rptr, XFS_BB_RIGHTSIB);
	if (!xfs_btree_ptr_is_null(cur, &rptr)) {
		/* Our block is left, pick up the right block. */
		lbp = bp;
		xfs_btree_buf_to_ptr(cur, lbp, &lptr);
		left = block;
		error = xfs_btree_read_buf_block(cur, &rptr,
					cur->bc_nlevels - 1, 0, &right, &rbp);
		if (error)
			goto error0;
		bp = rbp;
		nptr = 1;
	} else {
		/* Our block is right, pick up the left block. */
		rbp = bp;
		xfs_btree_buf_to_ptr(cur, rbp, &rptr);
		right = block;
		xfs_btree_get_sibling(cur, right, &lptr, XFS_BB_LEFTSIB);
		error = xfs_btree_read_buf_block(cur, &lptr,
					cur->bc_nlevels - 1, 0, &left, &lbp);
		if (error)
			goto error0;
		bp = lbp;
		nptr = 2;
	}
	/* Fill in the new block's btree header and log it. */
	xfs_btree_init_block(cur, cur->bc_nlevels, 2, new);
	xfs_btree_log_block(cur, nbp, XFS_BB_ALL_BITS);
	ASSERT(!xfs_btree_ptr_is_null(cur, &lptr) &&
			!xfs_btree_ptr_is_null(cur, &rptr));

	/* Fill in the key data in the new root. */
	if (xfs_btree_get_level(left) > 0) {
		xfs_btree_copy_keys(cur,
				xfs_btree_key_addr(cur, 1, new),
				xfs_btree_key_addr(cur, 1, left), 1);
		xfs_btree_copy_keys(cur,
				xfs_btree_key_addr(cur, 2, new),
				xfs_btree_key_addr(cur, 1, right), 1);
	} else {
		cur->bc_ops->init_key_from_rec(
				xfs_btree_key_addr(cur, 1, new),
				xfs_btree_rec_addr(cur, 1, left));
		cur->bc_ops->init_key_from_rec(
				xfs_btree_key_addr(cur, 2, new),
				xfs_btree_rec_addr(cur, 1, right));
	}
	xfs_btree_log_keys(cur, nbp, 1, 2);

	/* Fill in the pointer data in the new root. */
	xfs_btree_copy_ptrs(cur,
		xfs_btree_ptr_addr(cur, 1, new), &lptr, 1);
	xfs_btree_copy_ptrs(cur,
		xfs_btree_ptr_addr(cur, 2, new), &rptr, 1);
	xfs_btree_log_ptrs(cur, nbp, 1, 2);

	/* Fix up the cursor. */
	xfs_btree_setbuf(cur, cur->bc_nlevels, nbp);
	cur->bc_ptrs[cur->bc_nlevels] = nptr;
	cur->bc_nlevels++;
	XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
	*stat = 1;
	return 0;
error0:
	XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
	return error;
out0:
	XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
	*stat = 0;
	return 0;
}

STATIC int
xfs_btree_make_block_unfull(
	struct xfs_btree_cur	*cur,	/* btree cursor */
	int			level,	/* btree level */
	int			numrecs,/* # of recs in block */
	int			*oindex,/* old tree index */
	int			*index,	/* new tree index */
	union xfs_btree_ptr	*nptr,	/* new btree ptr */
	struct xfs_btree_cur	**ncur,	/* new btree cursor */
	union xfs_btree_rec	*nrec,	/* new record */
	int			*stat)
{
	union xfs_btree_key	key;	/* new btree key value */
	int			error = 0;

	if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
	    level == cur->bc_nlevels - 1) {
	    	struct xfs_inode *ip = cur->bc_private.b.ip;

		if (numrecs < cur->bc_ops->get_dmaxrecs(cur, level)) {
			/* A root block that can be made bigger. */

			xfs_iroot_realloc(ip, 1, cur->bc_private.b.whichfork);
		} else {
			/* A root block that needs replacing */
			int	logflags = 0;

			error = xfs_btree_new_iroot(cur, &logflags, stat);
			if (error || *stat == 0)
				return error;

			xfs_trans_log_inode(cur->bc_tp, ip, logflags);
		}

		return 0;
	}

	/* First, try shifting an entry to the right neighbor. */
	error = xfs_btree_rshift(cur, level, stat);
	if (error || *stat)
		return error;

	/* Next, try shifting an entry to the left neighbor. */
	error = xfs_btree_lshift(cur, level, stat);
	if (error)
		return error;

	if (*stat) {
		*oindex = *index = cur->bc_ptrs[level];
		return 0;
	}

	/*
	 * Next, try splitting the current block in half.
	 *
	 * If this works we have to re-set our variables because we
	 * could be in a different block now.
	 */
	error = xfs_btree_split(cur, level, nptr, &key, ncur, stat);
	if (error || *stat == 0)
		return error;


	*index = cur->bc_ptrs[level];
	cur->bc_ops->init_rec_from_key(&key, nrec);
	return 0;
}

/*
 * Insert one record/level.  Return information to the caller
 * allowing the next level up to proceed if necessary.
 */
STATIC int
xfs_btree_insrec(
	struct xfs_btree_cur	*cur,	/* btree cursor */
	int			level,	/* level to insert record at */
	union xfs_btree_ptr	*ptrp,	/* i/o: block number inserted */
	union xfs_btree_rec	*recp,	/* i/o: record data inserted */
	struct xfs_btree_cur	**curp,	/* output: new cursor replacing cur */
	int			*stat)	/* success/failure */
{
	struct xfs_btree_block	*block;	/* btree block */
	struct xfs_buf		*bp;	/* buffer for block */
	union xfs_btree_key	key;	/* btree key */
	union xfs_btree_ptr	nptr;	/* new block ptr */
	struct xfs_btree_cur	*ncur;	/* new btree cursor */
	union xfs_btree_rec	nrec;	/* new record count */
	int			optr;	/* old key/record index */
	int			ptr;	/* key/record index */
	int			numrecs;/* number of records */
	int			error;	/* error return value */
#ifdef DEBUG
	int			i;
#endif

	XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
	XFS_BTREE_TRACE_ARGIPR(cur, level, *ptrp, recp);

	ncur = NULL;

	/*
	 * If we have an external root pointer, and we've made it to the
	 * root level, allocate a new root block and we're done.
	 */
	if (!(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
	    (level >= cur->bc_nlevels)) {
		error = xfs_btree_new_root(cur, stat);
		xfs_btree_set_ptr_null(cur, ptrp);

		XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
		return error;
	}

	/* If we're off the left edge, return failure. */
	ptr = cur->bc_ptrs[level];
	if (ptr == 0) {
		XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
		*stat = 0;
		return 0;
	}

	/* Make a key out of the record data to be inserted, and save it. */
	cur->bc_ops->init_key_from_rec(&key, recp);

	optr = ptr;

	XFS_BTREE_STATS_INC(cur, insrec);

	/* Get pointers to the btree buffer and block. */
	block = xfs_btree_get_block(cur, level, &bp);
	numrecs = xfs_btree_get_numrecs(block);

#ifdef DEBUG
	error = xfs_btree_check_block(cur, block, level, bp);
	if (error)
		goto error0;

	/* Check that the new entry is being inserted in the right place. */
	if (ptr <= numrecs) {
		if (level == 0) {
			ASSERT(cur->bc_ops->recs_inorder(cur, recp,
				xfs_btree_rec_addr(cur, ptr, block)));
		} else {
			ASSERT(cur->bc_ops->keys_inorder(cur, &key,
				xfs_btree_key_addr(cur, ptr, block)));
		}
	}
#endif

	/*
	 * If the block is full, we can't insert the new entry until we
	 * make the block un-full.
	 */
	xfs_btree_set_ptr_null(cur, &nptr);
	if (numrecs == cur->bc_ops->get_maxrecs(cur, level)) {
		error = xfs_btree_make_block_unfull(cur, level, numrecs,
					&optr, &ptr, &nptr, &ncur, &nrec, stat);
		if (error || *stat == 0)
			goto error0;
	}

	/*
	 * The current block may have changed if the block was
	 * previously full and we have just made space in it.
	 */
	block = xfs_btree_get_block(cur, level, &bp);
	numrecs = xfs_btree_get_numrecs(block);

#ifdef DEBUG
	error = xfs_btree_check_block(cur, block, level, bp);
	if (error)
		return error;
#endif

	/*
	 * At this point we know there's room for our new entry in the block
	 * we're pointing at.
	 */
	XFS_BTREE_STATS_ADD(cur, moves, numrecs - ptr + 1);

	if (level > 0) {
		/* It's a nonleaf. make a hole in the keys and ptrs */
		union xfs_btree_key	*kp;
		union xfs_btree_ptr	*pp;

		kp = xfs_btree_key_addr(cur, ptr, block);
		pp = xfs_btree_ptr_addr(cur, ptr, block);

#ifdef DEBUG
		for (i = numrecs - ptr; i >= 0; i--) {
			error = xfs_btree_check_ptr(cur, pp, i, level);
			if (error)
				return error;
		}
#endif

		xfs_btree_shift_keys(cur, kp, 1, numrecs - ptr + 1);
		xfs_btree_shift_ptrs(cur, pp, 1, numrecs - ptr + 1);

#ifdef DEBUG
		error = xfs_btree_check_ptr(cur, ptrp, 0, level);
		if (error)
			goto error0;
#endif

		/* Now put the new data in, bump numrecs and log it. */
		xfs_btree_copy_keys(cur, kp, &key, 1);
		xfs_btree_copy_ptrs(cur, pp, ptrp, 1);
		numrecs++;
		xfs_btree_set_numrecs(block, numrecs);
		xfs_btree_log_ptrs(cur, bp, ptr, numrecs);
		xfs_btree_log_keys(cur, bp, ptr, numrecs);
#ifdef DEBUG
		if (ptr < numrecs) {
			ASSERT(cur->bc_ops->keys_inorder(cur, kp,
				xfs_btree_key_addr(cur, ptr + 1, block)));
		}
#endif
	} else {
		/* It's a leaf. make a hole in the records */
		union xfs_btree_rec             *rp;

		rp = xfs_btree_rec_addr(cur, ptr, block);

		xfs_btree_shift_recs(cur, rp, 1, numrecs - ptr + 1);

		/* Now put the new data in, bump numrecs and log it. */
		xfs_btree_copy_recs(cur, rp, recp, 1);
		xfs_btree_set_numrecs(block, ++numrecs);
		xfs_btree_log_recs(cur, bp, ptr, numrecs);
#ifdef DEBUG
		if (ptr < numrecs) {
			ASSERT(cur->bc_ops->recs_inorder(cur, rp,
				xfs_btree_rec_addr(cur, ptr + 1, block)));
		}
#endif
	}

	/* Log the new number of records in the btree header. */
	xfs_btree_log_block(cur, bp, XFS_BB_NUMRECS);

	/* If we inserted at the start of a block, update the parents' keys. */
	if (optr == 1) {
		error = xfs_btree_updkey(cur, &key, level + 1);
		if (error)
			goto error0;
	}

	/*
	 * If we are tracking the last record in the tree and
	 * we are at the far right edge of the tree, update it.
	 */
	if (xfs_btree_is_lastrec(cur, block, level)) {
		cur->bc_ops->update_lastrec(cur, block, recp,
					    ptr, LASTREC_INSREC);
	}

	/*
	 * Return the new block number, if any.
	 * If there is one, give back a record value and a cursor too.
	 */
	*ptrp = nptr;
	if (!xfs_btree_ptr_is_null(cur, &nptr)) {
		*recp = nrec;
		*curp = ncur;
	}

	XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
	*stat = 1;
	return 0;

error0:
	XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
	return error;
}

/*
 * Insert the record at the point referenced by cur.
 *
 * A multi-level split of the tree on insert will invalidate the original
 * cursor.  All callers of this function should assume that the cursor is
 * no longer valid and revalidate it.
 */
int
xfs_btree_insert(
	struct xfs_btree_cur	*cur,
	int			*stat)
{
	int			error;	/* error return value */
	int			i;	/* result value, 0 for failure */
	int			level;	/* current level number in btree */
	union xfs_btree_ptr	nptr;	/* new block number (split result) */
	struct xfs_btree_cur	*ncur;	/* new cursor (split result) */
	struct xfs_btree_cur	*pcur;	/* previous level's cursor */
	union xfs_btree_rec	rec;	/* record to insert */

	level = 0;
	ncur = NULL;
	pcur = cur;

	xfs_btree_set_ptr_null(cur, &nptr);
	cur->bc_ops->init_rec_from_cur(cur, &rec);

	/*
	 * Loop going up the tree, starting at the leaf level.
	 * Stop when we don't get a split block, that must mean that
	 * the insert is finished with this level.
	 */
	do {
		/*
		 * Insert nrec/nptr into this level of the tree.
		 * Note if we fail, nptr will be null.
		 */
		error = xfs_btree_insrec(pcur, level, &nptr, &rec, &ncur, &i);
		if (error) {
			if (pcur != cur)
				xfs_btree_del_cursor(pcur, XFS_BTREE_ERROR);
			goto error0;
		}

		XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
		level++;

		/*
		 * See if the cursor we just used is trash.
		 * Can't trash the caller's cursor, but otherwise we should
		 * if ncur is a new cursor or we're about to be done.
		 */
		if (pcur != cur &&
		    (ncur || xfs_btree_ptr_is_null(cur, &nptr))) {
			/* Save the state from the cursor before we trash it */
			if (cur->bc_ops->update_cursor)
				cur->bc_ops->update_cursor(pcur, cur);
			cur->bc_nlevels = pcur->bc_nlevels;
			xfs_btree_del_cursor(pcur, XFS_BTREE_NOERROR);
		}
		/* If we got a new cursor, switch to it. */
		if (ncur) {
			pcur = ncur;
			ncur = NULL;
		}
	} while (!xfs_btree_ptr_is_null(cur, &nptr));

	XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
	*stat = i;
	return 0;
error0:
	XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
	return error;
}

/*
 * Try to merge a non-leaf block back into the inode root.
 *
 * Note: the killroot names comes from the fact that we're effectively
 * killing the old root block.  But because we can't just delete the
 * inode we have to copy the single block it was pointing to into the
 * inode.
 */
int
xfs_btree_kill_iroot(
	struct xfs_btree_cur	*cur)
{
	int			whichfork = cur->bc_private.b.whichfork;
	struct xfs_inode	*ip = cur->bc_private.b.ip;
	struct xfs_ifork	*ifp = XFS_IFORK_PTR(ip, whichfork);
	struct xfs_btree_block	*block;
	struct xfs_btree_block	*cblock;
	union xfs_btree_key	*kp;
	union xfs_btree_key	*ckp;
	union xfs_btree_ptr	*pp;
	union xfs_btree_ptr	*cpp;
	struct xfs_buf		*cbp;
	int			level;
	int			index;
	int			numrecs;
#ifdef DEBUG
	union xfs_btree_ptr	ptr;
	int			i;
#endif

	XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);

	ASSERT(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE);
	ASSERT(cur->bc_nlevels > 1);

	/*
	 * Don't deal with the root block needs to be a leaf case.
	 * We're just going to turn the thing back into extents anyway.
	 */
	level = cur->bc_nlevels - 1;
	if (level == 1)
		goto out0;

	/*
	 * Give up if the root has multiple children.
	 */
	block = xfs_btree_get_iroot(cur);
	if (xfs_btree_get_numrecs(block) != 1)
		goto out0;

	cblock = xfs_btree_get_block(cur, level - 1, &cbp);
	numrecs = xfs_btree_get_numrecs(cblock);

	/*
	 * Only do this if the next level will fit.
	 * Then the data must be copied up to the inode,
	 * instead of freeing the root you free the next level.
	 */
	if (numrecs > cur->bc_ops->get_dmaxrecs(cur, level))
		goto out0;

	XFS_BTREE_STATS_INC(cur, killroot);

#ifdef DEBUG
	xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_LEFTSIB);
	ASSERT(xfs_btree_ptr_is_null(cur, &ptr));
	xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
	ASSERT(xfs_btree_ptr_is_null(cur, &ptr));
#endif

	index = numrecs - cur->bc_ops->get_maxrecs(cur, level);
	if (index) {
		xfs_iroot_realloc(cur->bc_private.b.ip, index,
				  cur->bc_private.b.whichfork);
		block = ifp->if_broot;
	}

	be16_add_cpu(&block->bb_numrecs, index);
	ASSERT(block->bb_numrecs == cblock->bb_numrecs);

	kp = xfs_btree_key_addr(cur, 1, block);
	ckp = xfs_btree_key_addr(cur, 1, cblock);
	xfs_btree_copy_keys(cur, kp, ckp, numrecs);

	pp = xfs_btree_ptr_addr(cur, 1, block);
	cpp = xfs_btree_ptr_addr(cur, 1, cblock);
#ifdef DEBUG
	for (i = 0; i < numrecs; i++) {
		int		error;

		error = xfs_btree_check_ptr(cur, cpp, i, level - 1);
		if (error) {
			XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
			return error;
		}
	}
#endif
	xfs_btree_copy_ptrs(cur, pp, cpp, numrecs);

	cur->bc_ops->free_block(cur, cbp);
	XFS_BTREE_STATS_INC(cur, free);

	cur->bc_bufs[level - 1] = NULL;
	be16_add_cpu(&block->bb_level, -1);
	xfs_trans_log_inode(cur->bc_tp, ip,
		XFS_ILOG_CORE | xfs_ilog_fbroot(cur->bc_private.b.whichfork));
	cur->bc_nlevels--;
out0:
	XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
	return 0;
}

STATIC int
xfs_btree_dec_cursor(
	struct xfs_btree_cur	*cur,
	int			level,
	int			*stat)
{
	int			error;
	int			i;

	if (level > 0) {
		error = xfs_btree_decrement(cur, level, &i);
		if (error)
			return error;
	}

	XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
	*stat = 1;
	return 0;
}

/*
 * Single level of the btree record deletion routine.
 * Delete record pointed to by cur/level.
 * Remove the record from its block then rebalance the tree.
 * Return 0 for error, 1 for done, 2 to go on to the next level.
 */
STATIC int					/* error */
xfs_btree_delrec(
	struct xfs_btree_cur	*cur,		/* btree cursor */
	int			level,		/* level removing record from */
	int			*stat)		/* fail/done/go-on */
{
	struct xfs_btree_block	*block;		/* btree block */
	union xfs_btree_ptr	cptr;		/* current block ptr */
	struct xfs_buf		*bp;		/* buffer for block */
	int			error;		/* error return value */
	int			i;		/* loop counter */
	union xfs_btree_key	key;		/* storage for keyp */
	union xfs_btree_key	*keyp = &key;	/* passed to the next level */
	union xfs_btree_ptr	lptr;		/* left sibling block ptr */
	struct xfs_buf		*lbp;		/* left buffer pointer */
	struct xfs_btree_block	*left;		/* left btree block */
	int			lrecs = 0;	/* left record count */
	int			ptr;		/* key/record index */
	union xfs_btree_ptr	rptr;		/* right sibling block ptr */
	struct xfs_buf		*rbp;		/* right buffer pointer */
	struct xfs_btree_block	*right;		/* right btree block */
	struct xfs_btree_block	*rrblock;	/* right-right btree block */
	struct xfs_buf		*rrbp;		/* right-right buffer pointer */
	int			rrecs = 0;	/* right record count */
	struct xfs_btree_cur	*tcur;		/* temporary btree cursor */
	int			numrecs;	/* temporary numrec count */

	XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
	XFS_BTREE_TRACE_ARGI(cur, level);

	tcur = NULL;

	/* Get the index of the entry being deleted, check for nothing there. */
	ptr = cur->bc_ptrs[level];
	if (ptr == 0) {
		XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
		*stat = 0;
		return 0;
	}

	/* Get the buffer & block containing the record or key/ptr. */
	block = xfs_btree_get_block(cur, level, &bp);
	numrecs = xfs_btree_get_numrecs(block);

#ifdef DEBUG
	error = xfs_btree_check_block(cur, block, level, bp);
	if (error)
		goto error0;
#endif

	/* Fail if we're off the end of the block. */
	if (ptr > numrecs) {
		XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
		*stat = 0;
		return 0;
	}

	XFS_BTREE_STATS_INC(cur, delrec);
	XFS_BTREE_STATS_ADD(cur, moves, numrecs - ptr);

	/* Excise the entries being deleted. */
	if (level > 0) {
		/* It's a nonleaf. operate on keys and ptrs */
		union xfs_btree_key	*lkp;
		union xfs_btree_ptr	*lpp;

		lkp = xfs_btree_key_addr(cur, ptr + 1, block);
		lpp = xfs_btree_ptr_addr(cur, ptr + 1, block);

#ifdef DEBUG
		for (i = 0; i < numrecs - ptr; i++) {
			error = xfs_btree_check_ptr(cur, lpp, i, level);
			if (error)
				goto error0;
		}
#endif

		if (ptr < numrecs) {
			xfs_btree_shift_keys(cur, lkp, -1, numrecs - ptr);
			xfs_btree_shift_ptrs(cur, lpp, -1, numrecs - ptr);
			xfs_btree_log_keys(cur, bp, ptr, numrecs - 1);
			xfs_btree_log_ptrs(cur, bp, ptr, numrecs - 1);
		}

		/*
		 * If it's the first record in the block, we'll need to pass a
		 * key up to the next level (updkey).
		 */
		if (ptr == 1)
			keyp = xfs_btree_key_addr(cur, 1, block);
	} else {
		/* It's a leaf. operate on records */
		if (ptr < numrecs) {
			xfs_btree_shift_recs(cur,
				xfs_btree_rec_addr(cur, ptr + 1, block),
				-1, numrecs - ptr);
			xfs_btree_log_recs(cur, bp, ptr, numrecs - 1);
		}

		/*
		 * If it's the first record in the block, we'll need a key
		 * structure to pass up to the next level (updkey).
		 */
		if (ptr == 1) {
			cur->bc_ops->init_key_from_rec(&key,
					xfs_btree_rec_addr(cur, 1, block));
			keyp = &key;
		}
	}

	/*
	 * Decrement and log the number of entries in the block.
	 */
	xfs_btree_set_numrecs(block, --numrecs);
	xfs_btree_log_block(cur, bp, XFS_BB_NUMRECS);

	/*
	 * If we are tracking the last record in the tree and
	 * we are at the far right edge of the tree, update it.
	 */
	if (xfs_btree_is_lastrec(cur, block, level)) {
		cur->bc_ops->update_lastrec(cur, block, NULL,
					    ptr, LASTREC_DELREC);
	}

	/*
	 * We're at the root level.  First, shrink the root block in-memory.
	 * Try to get rid of the next level down.  If we can't then there's
	 * nothing left to do.
	 */
	if (level == cur->bc_nlevels - 1) {
		if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) {
			xfs_iroot_realloc(cur->bc_private.b.ip, -1,
					  cur->bc_private.b.whichfork);

			error = xfs_btree_kill_iroot(cur);
			if (error)
				goto error0;

			error = xfs_btree_dec_cursor(cur, level, stat);
			if (error)
				goto error0;
			*stat = 1;
			return 0;
		}

		/*
		 * If this is the root level, and there's only one entry left,
		 * and it's NOT the leaf level, then we can get rid of this
		 * level.
		 */
		if (numrecs == 1 && level > 0) {
			union xfs_btree_ptr	*pp;
			/*
			 * pp is still set to the first pointer in the block.
			 * Make it the new root of the btree.
			 */
			pp = xfs_btree_ptr_addr(cur, 1, block);
			error = cur->bc_ops->kill_root(cur, bp, level, pp);
			if (error)
				goto error0;
		} else if (level > 0) {
			error = xfs_btree_dec_cursor(cur, level, stat);
			if (error)
				goto error0;
		}
		*stat = 1;
		return 0;
	}

	/*
	 * If we deleted the leftmost entry in the block, update the
	 * key values above us in the tree.
	 */
	if (ptr == 1) {
		error = xfs_btree_updkey(cur, keyp, level + 1);
		if (error)
			goto error0;
	}

	/*
	 * If the number of records remaining in the block is at least
	 * the minimum, we're done.
	 */
	if (numrecs >= cur->bc_ops->get_minrecs(cur, level)) {
		error = xfs_btree_dec_cursor(cur, level, stat);
		if (error)
			goto error0;
		return 0;
	}

	/*
	 * Otherwise, we have to move some records around to keep the
	 * tree balanced.  Look at the left and right sibling blocks to
	 * see if we can re-balance by moving only one record.
	 */
	xfs_btree_get_sibling(cur, block, &rptr, XFS_BB_RIGHTSIB);
	xfs_btree_get_sibling(cur, block, &lptr, XFS_BB_LEFTSIB);

	if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) {
		/*
		 * One child of root, need to get a chance to copy its contents
		 * into the root and delete it. Can't go up to next level,
		 * there's nothing to delete there.
		 */
		if (xfs_btree_ptr_is_null(cur, &rptr) &&
		    xfs_btree_ptr_is_null(cur, &lptr) &&
		    level == cur->bc_nlevels - 2) {
			error = xfs_btree_kill_iroot(cur);
			if (!error)
				error = xfs_btree_dec_cursor(cur, level, stat);
			if (error)
				goto error0;
			return 0;
		}
	}

	ASSERT(!xfs_btree_ptr_is_null(cur, &rptr) ||
	       !xfs_btree_ptr_is_null(cur, &lptr));

	/*
	 * Duplicate the cursor so our btree manipulations here won't
	 * disrupt the next level up.
	 */
	error = xfs_btree_dup_cursor(cur, &tcur);
	if (error)
		goto error0;

	/*
	 * If there's a right sibling, see if it's ok to shift an entry
	 * out of it.
	 */
	if (!xfs_btree_ptr_is_null(cur, &rptr)) {
		/*
		 * Move the temp cursor to the last entry in the next block.
		 * Actually any entry but the first would suffice.
		 */
		i = xfs_btree_lastrec(tcur, level);
		XFS_WANT_CORRUPTED_GOTO(i == 1, error0);

		error = xfs_btree_increment(tcur, level, &i);
		if (error)
			goto error0;
		XFS_WANT_CORRUPTED_GOTO(i == 1, error0);

		i = xfs_btree_lastrec(tcur, level);
		XFS_WANT_CORRUPTED_GOTO(i == 1, error0);

		/* Grab a pointer to the block. */
		right = xfs_btree_get_block(tcur, level, &rbp);
#ifdef DEBUG
		error = xfs_btree_check_block(tcur, right, level, rbp);
		if (error)
			goto error0;
#endif
		/* Grab the current block number, for future use. */
		xfs_btree_get_sibling(tcur, right, &cptr, XFS_BB_LEFTSIB);

		/*
		 * If right block is full enough so that removing one entry
		 * won't make it too empty, and left-shifting an entry out
		 * of right to us works, we're done.
		 */
		if (xfs_btree_get_numrecs(right) - 1 >=
		    cur->bc_ops->get_minrecs(tcur, level)) {
			error = xfs_btree_lshift(tcur, level, &i);
			if (error)
				goto error0;
			if (i) {
				ASSERT(xfs_btree_get_numrecs(block) >=
				       cur->bc_ops->get_minrecs(tcur, level));

				xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
				tcur = NULL;

				error = xfs_btree_dec_cursor(cur, level, stat);
				if (error)
					goto error0;
				return 0;
			}
		}

		/*
		 * Otherwise, grab the number of records in right for
		 * future reference, and fix up the temp cursor to point
		 * to our block again (last record).
		 */
		rrecs = xfs_btree_get_numrecs(right);
		if (!xfs_btree_ptr_is_null(cur, &lptr)) {
			i = xfs_btree_firstrec(tcur, level);
			XFS_WANT_CORRUPTED_GOTO(i == 1, error0);

			error = xfs_btree_decrement(tcur, level, &i);
			if (error)
				goto error0;
			XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
		}
	}

	/*
	 * If there's a left sibling, see if it's ok to shift an entry
	 * out of it.
	 */
	if (!xfs_btree_ptr_is_null(cur, &lptr)) {
		/*
		 * Move the temp cursor to the first entry in the
		 * previous block.
		 */
		i = xfs_btree_firstrec(tcur, level);
		XFS_WANT_CORRUPTED_GOTO(i == 1, error0);

		error = xfs_btree_decrement(tcur, level, &i);
		if (error)
			goto error0;
		i = xfs_btree_firstrec(tcur, level);
		XFS_WANT_CORRUPTED_GOTO(i == 1, error0);

		/* Grab a pointer to the block. */
		left = xfs_btree_get_block(tcur, level, &lbp);
#ifdef DEBUG
		error = xfs_btree_check_block(cur, left, level, lbp);
		if (error)
			goto error0;
#endif
		/* Grab the current block number, for future use. */
		xfs_btree_get_sibling(tcur, left, &cptr, XFS_BB_RIGHTSIB);

		/*
		 * If left block is full enough so that removing one entry
		 * won't make it too empty, and right-shifting an entry out
		 * of left to us works, we're done.
		 */
		if (xfs_btree_get_numrecs(left) - 1 >=
		    cur->bc_ops->get_minrecs(tcur, level)) {
			error = xfs_btree_rshift(tcur, level, &i);
			if (error)
				goto error0;
			if (i) {
				ASSERT(xfs_btree_get_numrecs(block) >=
				       cur->bc_ops->get_minrecs(tcur, level));
				xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
				tcur = NULL;
				if (level == 0)
					cur->bc_ptrs[0]++;
				XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
				*stat = 1;
				return 0;
			}
		}

		/*
		 * Otherwise, grab the number of records in right for
		 * future reference.
		 */
		lrecs = xfs_btree_get_numrecs(left);
	}

	/* Delete the temp cursor, we're done with it. */
	xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
	tcur = NULL;

	/* If here, we need to do a join to keep the tree balanced. */
	ASSERT(!xfs_btree_ptr_is_null(cur, &cptr));

	if (!xfs_btree_ptr_is_null(cur, &lptr) &&
	    lrecs + xfs_btree_get_numrecs(block) <=
			cur->bc_ops->get_maxrecs(cur, level)) {
		/*
		 * Set "right" to be the starting block,
		 * "left" to be the left neighbor.
		 */
		rptr = cptr;
		right = block;
		rbp = bp;
		error = xfs_btree_read_buf_block(cur, &lptr, level,
							0, &left, &lbp);
		if (error)
			goto error0;

	/*
	 * If that won't work, see if we can join with the right neighbor block.
	 */
	} else if (!xfs_btree_ptr_is_null(cur, &rptr) &&
		   rrecs + xfs_btree_get_numrecs(block) <=
			cur->bc_ops->get_maxrecs(cur, level)) {
		/*
		 * Set "left" to be the starting block,
		 * "right" to be the right neighbor.
		 */
		lptr = cptr;
		left = block;
		lbp = bp;
		error = xfs_btree_read_buf_block(cur, &rptr, level,
							0, &right, &rbp);
		if (error)
			goto error0;

	/*
	 * Otherwise, we can't fix the imbalance.
	 * Just return.  This is probably a logic error, but it's not fatal.
	 */
	} else {
		error = xfs_btree_dec_cursor(cur, level, stat);
		if (error)
			goto error0;
		return 0;
	}

	rrecs = xfs_btree_get_numrecs(right);
	lrecs = xfs_btree_get_numrecs(left);

	/*
	 * We're now going to join "left" and "right" by moving all the stuff
	 * in "right" to "left" and deleting "right".
	 */
	XFS_BTREE_STATS_ADD(cur, moves, rrecs);
	if (level > 0) {
		/* It's a non-leaf.  Move keys and pointers. */
		union xfs_btree_key	*lkp;	/* left btree key */
		union xfs_btree_ptr	*lpp;	/* left address pointer */
		union xfs_btree_key	*rkp;	/* right btree key */
		union xfs_btree_ptr	*rpp;	/* right address pointer */

		lkp = xfs_btree_key_addr(cur, lrecs + 1, left);
		lpp = xfs_btree_ptr_addr(cur, lrecs + 1, left);
		rkp = xfs_btree_key_addr(cur, 1, right);
		rpp = xfs_btree_ptr_addr(cur, 1, right);
#ifdef DEBUG
		for (i = 1; i < rrecs; i++) {
			error = xfs_btree_check_ptr(cur, rpp, i, level);
			if (error)
				goto error0;
		}
#endif
		xfs_btree_copy_keys(cur, lkp, rkp, rrecs);
		xfs_btree_copy_ptrs(cur, lpp, rpp, rrecs);

		xfs_btree_log_keys(cur, lbp, lrecs + 1, lrecs + rrecs);
		xfs_btree_log_ptrs(cur, lbp, lrecs + 1, lrecs + rrecs);
	} else {
		/* It's a leaf.  Move records.  */
		union xfs_btree_rec	*lrp;	/* left record pointer */
		union xfs_btree_rec	*rrp;	/* right record pointer */

		lrp = xfs_btree_rec_addr(cur, lrecs + 1, left);
		rrp = xfs_btree_rec_addr(cur, 1, right);

		xfs_btree_copy_recs(cur, lrp, rrp, rrecs);
		xfs_btree_log_recs(cur, lbp, lrecs + 1, lrecs + rrecs);
	}

	XFS_BTREE_STATS_INC(cur, join);

	/*
	 * Fix up the number of records and right block pointer in the
	 * surviving block, and log it.
	 */
	xfs_btree_set_numrecs(left, lrecs + rrecs);
	xfs_btree_get_sibling(cur, right, &cptr, XFS_BB_RIGHTSIB),
	xfs_btree_set_sibling(cur, left, &cptr, XFS_BB_RIGHTSIB);
	xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS | XFS_BB_RIGHTSIB);

	/* If there is a right sibling, point it to the remaining block. */
	xfs_btree_get_sibling(cur, left, &cptr, XFS_BB_RIGHTSIB);
	if (!xfs_btree_ptr_is_null(cur, &cptr)) {
		error = xfs_btree_read_buf_block(cur, &cptr, level,
							0, &rrblock, &rrbp);
		if (error)
			goto error0;
		xfs_btree_set_sibling(cur, rrblock, &lptr, XFS_BB_LEFTSIB);
		xfs_btree_log_block(cur, rrbp, XFS_BB_LEFTSIB);
	}

	/* Free the deleted block. */
	error = cur->bc_ops->free_block(cur, rbp);
	if (error)
		goto error0;
	XFS_BTREE_STATS_INC(cur, free);

	/*
	 * If we joined with the left neighbor, set the buffer in the
	 * cursor to the left block, and fix up the index.
	 */
	if (bp != lbp) {
		cur->bc_bufs[level] = lbp;
		cur->bc_ptrs[level] += lrecs;
		cur->bc_ra[level] = 0;
	}
	/*
	 * If we joined with the right neighbor and there's a level above
	 * us, increment the cursor at that level.
	 */
	else if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) ||
		   (level + 1 < cur->bc_nlevels)) {
		error = xfs_btree_increment(cur, level + 1, &i);
		if (error)
			goto error0;
	}

	/*
	 * Readjust the ptr at this level if it's not a leaf, since it's
	 * still pointing at the deletion point, which makes the cursor
	 * inconsistent.  If this makes the ptr 0, the caller fixes it up.
	 * We can't use decrement because it would change the next level up.
	 */
	if (level > 0)
		cur->bc_ptrs[level]--;

	XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
	/* Return value means the next level up has something to do. */
	*stat = 2;
	return 0;

error0:
	XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
	if (tcur)
		xfs_btree_del_cursor(tcur, XFS_BTREE_ERROR);
	return error;
}

/*
 * Delete the record pointed to by cur.
 * The cursor refers to the place where the record was (could be inserted)
 * when the operation returns.
 */
int					/* error */
xfs_btree_delete(
	struct xfs_btree_cur	*cur,
	int			*stat)	/* success/failure */
{
	int			error;	/* error return value */
	int			level;
	int			i;

	XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);

	/*
	 * Go up the tree, starting at leaf level.
	 *
	 * If 2 is returned then a join was done; go to the next level.
	 * Otherwise we are done.
	 */
	for (level = 0, i = 2; i == 2; level++) {
		error = xfs_btree_delrec(cur, level, &i);
		if (error)
			goto error0;
	}

	if (i == 0) {
		for (level = 1; level < cur->bc_nlevels; level++) {
			if (cur->bc_ptrs[level] == 0) {
				error = xfs_btree_decrement(cur, level, &i);
				if (error)
					goto error0;
				break;
			}
		}
	}

	XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
	*stat = i;
	return 0;
error0:
	XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
	return error;
}

/*
 * Get the data from the pointed-to record.
 */
int					/* error */
xfs_btree_get_rec(
	struct xfs_btree_cur	*cur,	/* btree cursor */
	union xfs_btree_rec	**recp,	/* output: btree record */
	int			*stat)	/* output: success/failure */
{
	struct xfs_btree_block	*block;	/* btree block */
	struct xfs_buf		*bp;	/* buffer pointer */
	int			ptr;	/* record number */
#ifdef DEBUG
	int			error;	/* error return value */
#endif

	ptr = cur->bc_ptrs[0];
	block = xfs_btree_get_block(cur, 0, &bp);

#ifdef DEBUG
	error = xfs_btree_check_block(cur, block, 0, bp);
	if (error)
		return error;
#endif

	/*
	 * Off the right end or left end, return failure.
	 */
	if (ptr > xfs_btree_get_numrecs(block) || ptr <= 0) {
		*stat = 0;
		return 0;
	}

	/*
	 * Point to the record and extract its data.
	 */
	*recp = xfs_btree_rec_addr(cur, ptr, block);
	*stat = 1;
	return 0;
}