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   1/*
   2 * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
   3 * All Rights Reserved.
   4 *
   5 * This program is free software; you can redistribute it and/or
   6 * modify it under the terms of the GNU General Public License as
   7 * published by the Free Software Foundation.
   8 *
   9 * This program is distributed in the hope that it would be useful,
  10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 * GNU General Public License for more details.
  13 *
  14 * You should have received a copy of the GNU General Public License
  15 * along with this program; if not, write the Free Software Foundation,
  16 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17 */
  18#include "xfs.h"
  19#include "xfs_fs.h"
  20#include "xfs_types.h"
  21#include "xfs_bit.h"
  22#include "xfs_log.h"
  23#include "xfs_inum.h"
  24#include "xfs_trans.h"
  25#include "xfs_sb.h"
  26#include "xfs_ag.h"
  27#include "xfs_mount.h"
  28#include "xfs_bmap_btree.h"
  29#include "xfs_alloc_btree.h"
  30#include "xfs_ialloc_btree.h"
  31#include "xfs_dinode.h"
  32#include "xfs_inode.h"
  33#include "xfs_btree.h"
  34#include "xfs_ialloc.h"
  35#include "xfs_alloc.h"
  36#include "xfs_rtalloc.h"
  37#include "xfs_error.h"
  38#include "xfs_bmap.h"
  39
  40
  41/*
  42 * Allocation group level functions.
  43 */
  44static inline int
  45xfs_ialloc_cluster_alignment(
  46	xfs_alloc_arg_t	*args)
  47{
  48	if (xfs_sb_version_hasalign(&args->mp->m_sb) &&
  49	    args->mp->m_sb.sb_inoalignmt >=
  50	     XFS_B_TO_FSBT(args->mp, XFS_INODE_CLUSTER_SIZE(args->mp)))
  51		return args->mp->m_sb.sb_inoalignmt;
  52	return 1;
  53}
  54
  55/*
  56 * Lookup a record by ino in the btree given by cur.
  57 */
  58int					/* error */
  59xfs_inobt_lookup(
  60	struct xfs_btree_cur	*cur,	/* btree cursor */
  61	xfs_agino_t		ino,	/* starting inode of chunk */
  62	xfs_lookup_t		dir,	/* <=, >=, == */
  63	int			*stat)	/* success/failure */
  64{
  65	cur->bc_rec.i.ir_startino = ino;
  66	cur->bc_rec.i.ir_freecount = 0;
  67	cur->bc_rec.i.ir_free = 0;
  68	return xfs_btree_lookup(cur, dir, stat);
  69}
  70
  71/*
  72 * Update the record referred to by cur to the value given.
  73 * This either works (return 0) or gets an EFSCORRUPTED error.
  74 */
  75STATIC int				/* error */
  76xfs_inobt_update(
  77	struct xfs_btree_cur	*cur,	/* btree cursor */
  78	xfs_inobt_rec_incore_t	*irec)	/* btree record */
  79{
  80	union xfs_btree_rec	rec;
  81
  82	rec.inobt.ir_startino = cpu_to_be32(irec->ir_startino);
  83	rec.inobt.ir_freecount = cpu_to_be32(irec->ir_freecount);
  84	rec.inobt.ir_free = cpu_to_be64(irec->ir_free);
  85	return xfs_btree_update(cur, &rec);
  86}
  87
  88/*
  89 * Get the data from the pointed-to record.
  90 */
  91int					/* error */
  92xfs_inobt_get_rec(
  93	struct xfs_btree_cur	*cur,	/* btree cursor */
  94	xfs_inobt_rec_incore_t	*irec,	/* btree record */
  95	int			*stat)	/* output: success/failure */
  96{
  97	union xfs_btree_rec	*rec;
  98	int			error;
  99
 100	error = xfs_btree_get_rec(cur, &rec, stat);
 101	if (!error && *stat == 1) {
 102		irec->ir_startino = be32_to_cpu(rec->inobt.ir_startino);
 103		irec->ir_freecount = be32_to_cpu(rec->inobt.ir_freecount);
 104		irec->ir_free = be64_to_cpu(rec->inobt.ir_free);
 105	}
 106	return error;
 107}
 108
 109/*
 110 * Verify that the number of free inodes in the AGI is correct.
 111 */
 112#ifdef DEBUG
 113STATIC int
 114xfs_check_agi_freecount(
 115	struct xfs_btree_cur	*cur,
 116	struct xfs_agi		*agi)
 117{
 118	if (cur->bc_nlevels == 1) {
 119		xfs_inobt_rec_incore_t rec;
 120		int		freecount = 0;
 121		int		error;
 122		int		i;
 123
 124		error = xfs_inobt_lookup(cur, 0, XFS_LOOKUP_GE, &i);
 125		if (error)
 126			return error;
 127
 128		do {
 129			error = xfs_inobt_get_rec(cur, &rec, &i);
 130			if (error)
 131				return error;
 132
 133			if (i) {
 134				freecount += rec.ir_freecount;
 135				error = xfs_btree_increment(cur, 0, &i);
 136				if (error)
 137					return error;
 138			}
 139		} while (i == 1);
 140
 141		if (!XFS_FORCED_SHUTDOWN(cur->bc_mp))
 142			ASSERT(freecount == be32_to_cpu(agi->agi_freecount));
 143	}
 144	return 0;
 145}
 146#else
 147#define xfs_check_agi_freecount(cur, agi)	0
 148#endif
 149
 150/*
 151 * Initialise a new set of inodes.
 152 */
 153STATIC void
 154xfs_ialloc_inode_init(
 155	struct xfs_mount	*mp,
 156	struct xfs_trans	*tp,
 157	xfs_agnumber_t		agno,
 158	xfs_agblock_t		agbno,
 159	xfs_agblock_t		length,
 160	unsigned int		gen)
 161{
 162	struct xfs_buf		*fbuf;
 163	struct xfs_dinode	*free;
 164	int			blks_per_cluster, nbufs, ninodes;
 165	int			version;
 166	int			i, j;
 167	xfs_daddr_t		d;
 168
 169	/*
 170	 * Loop over the new block(s), filling in the inodes.
 171	 * For small block sizes, manipulate the inodes in buffers
 172	 * which are multiples of the blocks size.
 173	 */
 174	if (mp->m_sb.sb_blocksize >= XFS_INODE_CLUSTER_SIZE(mp)) {
 175		blks_per_cluster = 1;
 176		nbufs = length;
 177		ninodes = mp->m_sb.sb_inopblock;
 178	} else {
 179		blks_per_cluster = XFS_INODE_CLUSTER_SIZE(mp) /
 180				   mp->m_sb.sb_blocksize;
 181		nbufs = length / blks_per_cluster;
 182		ninodes = blks_per_cluster * mp->m_sb.sb_inopblock;
 183	}
 184
 185	/*
 186	 * Figure out what version number to use in the inodes we create.
 187	 * If the superblock version has caught up to the one that supports
 188	 * the new inode format, then use the new inode version.  Otherwise
 189	 * use the old version so that old kernels will continue to be
 190	 * able to use the file system.
 191	 */
 192	if (xfs_sb_version_hasnlink(&mp->m_sb))
 193		version = 2;
 194	else
 195		version = 1;
 196
 197	for (j = 0; j < nbufs; j++) {
 198		/*
 199		 * Get the block.
 200		 */
 201		d = XFS_AGB_TO_DADDR(mp, agno, agbno + (j * blks_per_cluster));
 202		fbuf = xfs_trans_get_buf(tp, mp->m_ddev_targp, d,
 203					 mp->m_bsize * blks_per_cluster,
 204					 XBF_LOCK);
 205		ASSERT(!xfs_buf_geterror(fbuf));
 206
 207		/*
 208		 * Initialize all inodes in this buffer and then log them.
 209		 *
 210		 * XXX: It would be much better if we had just one transaction
 211		 *	to log a whole cluster of inodes instead of all the
 212		 *	individual transactions causing a lot of log traffic.
 213		 */
 214		xfs_buf_zero(fbuf, 0, ninodes << mp->m_sb.sb_inodelog);
 215		for (i = 0; i < ninodes; i++) {
 216			int	ioffset = i << mp->m_sb.sb_inodelog;
 217			uint	isize = sizeof(struct xfs_dinode);
 218
 219			free = xfs_make_iptr(mp, fbuf, i);
 220			free->di_magic = cpu_to_be16(XFS_DINODE_MAGIC);
 221			free->di_version = version;
 222			free->di_gen = cpu_to_be32(gen);
 223			free->di_next_unlinked = cpu_to_be32(NULLAGINO);
 224			xfs_trans_log_buf(tp, fbuf, ioffset, ioffset + isize - 1);
 225		}
 226		xfs_trans_inode_alloc_buf(tp, fbuf);
 227	}
 228}
 229
 230/*
 231 * Allocate new inodes in the allocation group specified by agbp.
 232 * Return 0 for success, else error code.
 233 */
 234STATIC int				/* error code or 0 */
 235xfs_ialloc_ag_alloc(
 236	xfs_trans_t	*tp,		/* transaction pointer */
 237	xfs_buf_t	*agbp,		/* alloc group buffer */
 238	int		*alloc)
 239{
 240	xfs_agi_t	*agi;		/* allocation group header */
 241	xfs_alloc_arg_t	args;		/* allocation argument structure */
 242	xfs_btree_cur_t	*cur;		/* inode btree cursor */
 243	xfs_agnumber_t	agno;
 244	int		error;
 245	int		i;
 246	xfs_agino_t	newino;		/* new first inode's number */
 247	xfs_agino_t	newlen;		/* new number of inodes */
 248	xfs_agino_t	thisino;	/* current inode number, for loop */
 249	int		isaligned = 0;	/* inode allocation at stripe unit */
 250					/* boundary */
 251	struct xfs_perag *pag;
 252
 253	args.tp = tp;
 254	args.mp = tp->t_mountp;
 255
 256	/*
 257	 * Locking will ensure that we don't have two callers in here
 258	 * at one time.
 259	 */
 260	newlen = XFS_IALLOC_INODES(args.mp);
 261	if (args.mp->m_maxicount &&
 262	    args.mp->m_sb.sb_icount + newlen > args.mp->m_maxicount)
 263		return XFS_ERROR(ENOSPC);
 264	args.minlen = args.maxlen = XFS_IALLOC_BLOCKS(args.mp);
 265	/*
 266	 * First try to allocate inodes contiguous with the last-allocated
 267	 * chunk of inodes.  If the filesystem is striped, this will fill
 268	 * an entire stripe unit with inodes.
 269 	 */
 270	agi = XFS_BUF_TO_AGI(agbp);
 271	newino = be32_to_cpu(agi->agi_newino);
 272	agno = be32_to_cpu(agi->agi_seqno);
 273	args.agbno = XFS_AGINO_TO_AGBNO(args.mp, newino) +
 274			XFS_IALLOC_BLOCKS(args.mp);
 275	if (likely(newino != NULLAGINO &&
 276		  (args.agbno < be32_to_cpu(agi->agi_length)))) {
 277		args.fsbno = XFS_AGB_TO_FSB(args.mp, agno, args.agbno);
 278		args.type = XFS_ALLOCTYPE_THIS_BNO;
 279		args.mod = args.total = args.wasdel = args.isfl =
 280			args.userdata = args.minalignslop = 0;
 281		args.prod = 1;
 282
 283		/*
 284		 * We need to take into account alignment here to ensure that
 285		 * we don't modify the free list if we fail to have an exact
 286		 * block. If we don't have an exact match, and every oher
 287		 * attempt allocation attempt fails, we'll end up cancelling
 288		 * a dirty transaction and shutting down.
 289		 *
 290		 * For an exact allocation, alignment must be 1,
 291		 * however we need to take cluster alignment into account when
 292		 * fixing up the freelist. Use the minalignslop field to
 293		 * indicate that extra blocks might be required for alignment,
 294		 * but not to use them in the actual exact allocation.
 295		 */
 296		args.alignment = 1;
 297		args.minalignslop = xfs_ialloc_cluster_alignment(&args) - 1;
 298
 299		/* Allow space for the inode btree to split. */
 300		args.minleft = args.mp->m_in_maxlevels - 1;
 301		if ((error = xfs_alloc_vextent(&args)))
 302			return error;
 303	} else
 304		args.fsbno = NULLFSBLOCK;
 305
 306	if (unlikely(args.fsbno == NULLFSBLOCK)) {
 307		/*
 308		 * Set the alignment for the allocation.
 309		 * If stripe alignment is turned on then align at stripe unit
 310		 * boundary.
 311		 * If the cluster size is smaller than a filesystem block
 312		 * then we're doing I/O for inodes in filesystem block size
 313		 * pieces, so don't need alignment anyway.
 314		 */
 315		isaligned = 0;
 316		if (args.mp->m_sinoalign) {
 317			ASSERT(!(args.mp->m_flags & XFS_MOUNT_NOALIGN));
 318			args.alignment = args.mp->m_dalign;
 319			isaligned = 1;
 320		} else
 321			args.alignment = xfs_ialloc_cluster_alignment(&args);
 322		/*
 323		 * Need to figure out where to allocate the inode blocks.
 324		 * Ideally they should be spaced out through the a.g.
 325		 * For now, just allocate blocks up front.
 326		 */
 327		args.agbno = be32_to_cpu(agi->agi_root);
 328		args.fsbno = XFS_AGB_TO_FSB(args.mp, agno, args.agbno);
 329		/*
 330		 * Allocate a fixed-size extent of inodes.
 331		 */
 332		args.type = XFS_ALLOCTYPE_NEAR_BNO;
 333		args.mod = args.total = args.wasdel = args.isfl =
 334			args.userdata = args.minalignslop = 0;
 335		args.prod = 1;
 336		/*
 337		 * Allow space for the inode btree to split.
 338		 */
 339		args.minleft = args.mp->m_in_maxlevels - 1;
 340		if ((error = xfs_alloc_vextent(&args)))
 341			return error;
 342	}
 343
 344	/*
 345	 * If stripe alignment is turned on, then try again with cluster
 346	 * alignment.
 347	 */
 348	if (isaligned && args.fsbno == NULLFSBLOCK) {
 349		args.type = XFS_ALLOCTYPE_NEAR_BNO;
 350		args.agbno = be32_to_cpu(agi->agi_root);
 351		args.fsbno = XFS_AGB_TO_FSB(args.mp, agno, args.agbno);
 352		args.alignment = xfs_ialloc_cluster_alignment(&args);
 353		if ((error = xfs_alloc_vextent(&args)))
 354			return error;
 355	}
 356
 357	if (args.fsbno == NULLFSBLOCK) {
 358		*alloc = 0;
 359		return 0;
 360	}
 361	ASSERT(args.len == args.minlen);
 362
 363	/*
 364	 * Stamp and write the inode buffers.
 365	 *
 366	 * Seed the new inode cluster with a random generation number. This
 367	 * prevents short-term reuse of generation numbers if a chunk is
 368	 * freed and then immediately reallocated. We use random numbers
 369	 * rather than a linear progression to prevent the next generation
 370	 * number from being easily guessable.
 371	 */
 372	xfs_ialloc_inode_init(args.mp, tp, agno, args.agbno, args.len,
 373			      random32());
 374
 375	/*
 376	 * Convert the results.
 377	 */
 378	newino = XFS_OFFBNO_TO_AGINO(args.mp, args.agbno, 0);
 379	be32_add_cpu(&agi->agi_count, newlen);
 380	be32_add_cpu(&agi->agi_freecount, newlen);
 381	pag = xfs_perag_get(args.mp, agno);
 382	pag->pagi_freecount += newlen;
 383	xfs_perag_put(pag);
 384	agi->agi_newino = cpu_to_be32(newino);
 385
 386	/*
 387	 * Insert records describing the new inode chunk into the btree.
 388	 */
 389	cur = xfs_inobt_init_cursor(args.mp, tp, agbp, agno);
 390	for (thisino = newino;
 391	     thisino < newino + newlen;
 392	     thisino += XFS_INODES_PER_CHUNK) {
 393		cur->bc_rec.i.ir_startino = thisino;
 394		cur->bc_rec.i.ir_freecount = XFS_INODES_PER_CHUNK;
 395		cur->bc_rec.i.ir_free = XFS_INOBT_ALL_FREE;
 396		error = xfs_btree_lookup(cur, XFS_LOOKUP_EQ, &i);
 397		if (error) {
 398			xfs_btree_del_cursor(cur, XFS_BTREE_ERROR);
 399			return error;
 400		}
 401		ASSERT(i == 0);
 402		error = xfs_btree_insert(cur, &i);
 403		if (error) {
 404			xfs_btree_del_cursor(cur, XFS_BTREE_ERROR);
 405			return error;
 406		}
 407		ASSERT(i == 1);
 408	}
 409	xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
 410	/*
 411	 * Log allocation group header fields
 412	 */
 413	xfs_ialloc_log_agi(tp, agbp,
 414		XFS_AGI_COUNT | XFS_AGI_FREECOUNT | XFS_AGI_NEWINO);
 415	/*
 416	 * Modify/log superblock values for inode count and inode free count.
 417	 */
 418	xfs_trans_mod_sb(tp, XFS_TRANS_SB_ICOUNT, (long)newlen);
 419	xfs_trans_mod_sb(tp, XFS_TRANS_SB_IFREE, (long)newlen);
 420	*alloc = 1;
 421	return 0;
 422}
 423
 424STATIC xfs_agnumber_t
 425xfs_ialloc_next_ag(
 426	xfs_mount_t	*mp)
 427{
 428	xfs_agnumber_t	agno;
 429
 430	spin_lock(&mp->m_agirotor_lock);
 431	agno = mp->m_agirotor;
 432	if (++mp->m_agirotor == mp->m_maxagi)
 433		mp->m_agirotor = 0;
 434	spin_unlock(&mp->m_agirotor_lock);
 435
 436	return agno;
 437}
 438
 439/*
 440 * Select an allocation group to look for a free inode in, based on the parent
 441 * inode and then mode.  Return the allocation group buffer.
 442 */
 443STATIC xfs_buf_t *			/* allocation group buffer */
 444xfs_ialloc_ag_select(
 445	xfs_trans_t	*tp,		/* transaction pointer */
 446	xfs_ino_t	parent,		/* parent directory inode number */
 447	mode_t		mode,		/* bits set to indicate file type */
 448	int		okalloc)	/* ok to allocate more space */
 449{
 450	xfs_buf_t	*agbp;		/* allocation group header buffer */
 451	xfs_agnumber_t	agcount;	/* number of ag's in the filesystem */
 452	xfs_agnumber_t	agno;		/* current ag number */
 453	int		flags;		/* alloc buffer locking flags */
 454	xfs_extlen_t	ineed;		/* blocks needed for inode allocation */
 455	xfs_extlen_t	longest = 0;	/* longest extent available */
 456	xfs_mount_t	*mp;		/* mount point structure */
 457	int		needspace;	/* file mode implies space allocated */
 458	xfs_perag_t	*pag;		/* per allocation group data */
 459	xfs_agnumber_t	pagno;		/* parent (starting) ag number */
 460
 461	/*
 462	 * Files of these types need at least one block if length > 0
 463	 * (and they won't fit in the inode, but that's hard to figure out).
 464	 */
 465	needspace = S_ISDIR(mode) || S_ISREG(mode) || S_ISLNK(mode);
 466	mp = tp->t_mountp;
 467	agcount = mp->m_maxagi;
 468	if (S_ISDIR(mode))
 469		pagno = xfs_ialloc_next_ag(mp);
 470	else {
 471		pagno = XFS_INO_TO_AGNO(mp, parent);
 472		if (pagno >= agcount)
 473			pagno = 0;
 474	}
 475	ASSERT(pagno < agcount);
 476	/*
 477	 * Loop through allocation groups, looking for one with a little
 478	 * free space in it.  Note we don't look for free inodes, exactly.
 479	 * Instead, we include whether there is a need to allocate inodes
 480	 * to mean that blocks must be allocated for them,
 481	 * if none are currently free.
 482	 */
 483	agno = pagno;
 484	flags = XFS_ALLOC_FLAG_TRYLOCK;
 485	for (;;) {
 486		pag = xfs_perag_get(mp, agno);
 487		if (!pag->pagi_init) {
 488			if (xfs_ialloc_read_agi(mp, tp, agno, &agbp)) {
 489				agbp = NULL;
 490				goto nextag;
 491			}
 492		} else
 493			agbp = NULL;
 494
 495		if (!pag->pagi_inodeok) {
 496			xfs_ialloc_next_ag(mp);
 497			goto unlock_nextag;
 498		}
 499
 500		/*
 501		 * Is there enough free space for the file plus a block
 502		 * of inodes (if we need to allocate some)?
 503		 */
 504		ineed = pag->pagi_freecount ? 0 : XFS_IALLOC_BLOCKS(mp);
 505		if (ineed && !pag->pagf_init) {
 506			if (agbp == NULL &&
 507			    xfs_ialloc_read_agi(mp, tp, agno, &agbp)) {
 508				agbp = NULL;
 509				goto nextag;
 510			}
 511			(void)xfs_alloc_pagf_init(mp, tp, agno, flags);
 512		}
 513		if (!ineed || pag->pagf_init) {
 514			if (ineed && !(longest = pag->pagf_longest))
 515				longest = pag->pagf_flcount > 0;
 516			if (!ineed ||
 517			    (pag->pagf_freeblks >= needspace + ineed &&
 518			     longest >= ineed &&
 519			     okalloc)) {
 520				if (agbp == NULL &&
 521				    xfs_ialloc_read_agi(mp, tp, agno, &agbp)) {
 522					agbp = NULL;
 523					goto nextag;
 524				}
 525				xfs_perag_put(pag);
 526				return agbp;
 527			}
 528		}
 529unlock_nextag:
 530		if (agbp)
 531			xfs_trans_brelse(tp, agbp);
 532nextag:
 533		xfs_perag_put(pag);
 534		/*
 535		 * No point in iterating over the rest, if we're shutting
 536		 * down.
 537		 */
 538		if (XFS_FORCED_SHUTDOWN(mp))
 539			return NULL;
 540		agno++;
 541		if (agno >= agcount)
 542			agno = 0;
 543		if (agno == pagno) {
 544			if (flags == 0)
 545				return NULL;
 546			flags = 0;
 547		}
 548	}
 549}
 550
 551/*
 552 * Try to retrieve the next record to the left/right from the current one.
 553 */
 554STATIC int
 555xfs_ialloc_next_rec(
 556	struct xfs_btree_cur	*cur,
 557	xfs_inobt_rec_incore_t	*rec,
 558	int			*done,
 559	int			left)
 560{
 561	int                     error;
 562	int			i;
 563
 564	if (left)
 565		error = xfs_btree_decrement(cur, 0, &i);
 566	else
 567		error = xfs_btree_increment(cur, 0, &i);
 568
 569	if (error)
 570		return error;
 571	*done = !i;
 572	if (i) {
 573		error = xfs_inobt_get_rec(cur, rec, &i);
 574		if (error)
 575			return error;
 576		XFS_WANT_CORRUPTED_RETURN(i == 1);
 577	}
 578
 579	return 0;
 580}
 581
 582STATIC int
 583xfs_ialloc_get_rec(
 584	struct xfs_btree_cur	*cur,
 585	xfs_agino_t		agino,
 586	xfs_inobt_rec_incore_t	*rec,
 587	int			*done,
 588	int			left)
 589{
 590	int                     error;
 591	int			i;
 592
 593	error = xfs_inobt_lookup(cur, agino, XFS_LOOKUP_EQ, &i);
 594	if (error)
 595		return error;
 596	*done = !i;
 597	if (i) {
 598		error = xfs_inobt_get_rec(cur, rec, &i);
 599		if (error)
 600			return error;
 601		XFS_WANT_CORRUPTED_RETURN(i == 1);
 602	}
 603
 604	return 0;
 605}
 606
 607/*
 608 * Visible inode allocation functions.
 609 */
 610
 611/*
 612 * Allocate an inode on disk.
 613 * Mode is used to tell whether the new inode will need space, and whether
 614 * it is a directory.
 615 *
 616 * The arguments IO_agbp and alloc_done are defined to work within
 617 * the constraint of one allocation per transaction.
 618 * xfs_dialloc() is designed to be called twice if it has to do an
 619 * allocation to make more free inodes.  On the first call,
 620 * IO_agbp should be set to NULL. If an inode is available,
 621 * i.e., xfs_dialloc() did not need to do an allocation, an inode
 622 * number is returned.  In this case, IO_agbp would be set to the
 623 * current ag_buf and alloc_done set to false.
 624 * If an allocation needed to be done, xfs_dialloc would return
 625 * the current ag_buf in IO_agbp and set alloc_done to true.
 626 * The caller should then commit the current transaction, allocate a new
 627 * transaction, and call xfs_dialloc() again, passing in the previous
 628 * value of IO_agbp.  IO_agbp should be held across the transactions.
 629 * Since the agbp is locked across the two calls, the second call is
 630 * guaranteed to have a free inode available.
 631 *
 632 * Once we successfully pick an inode its number is returned and the
 633 * on-disk data structures are updated.  The inode itself is not read
 634 * in, since doing so would break ordering constraints with xfs_reclaim.
 635 */
 636int
 637xfs_dialloc(
 638	xfs_trans_t	*tp,		/* transaction pointer */
 639	xfs_ino_t	parent,		/* parent inode (directory) */
 640	mode_t		mode,		/* mode bits for new inode */
 641	int		okalloc,	/* ok to allocate more space */
 642	xfs_buf_t	**IO_agbp,	/* in/out ag header's buffer */
 643	boolean_t	*alloc_done,	/* true if we needed to replenish
 644					   inode freelist */
 645	xfs_ino_t	*inop)		/* inode number allocated */
 646{
 647	xfs_agnumber_t	agcount;	/* number of allocation groups */
 648	xfs_buf_t	*agbp;		/* allocation group header's buffer */
 649	xfs_agnumber_t	agno;		/* allocation group number */
 650	xfs_agi_t	*agi;		/* allocation group header structure */
 651	xfs_btree_cur_t	*cur;		/* inode allocation btree cursor */
 652	int		error;		/* error return value */
 653	int		i;		/* result code */
 654	int		ialloced;	/* inode allocation status */
 655	int		noroom = 0;	/* no space for inode blk allocation */
 656	xfs_ino_t	ino;		/* fs-relative inode to be returned */
 657	/* REFERENCED */
 658	int		j;		/* result code */
 659	xfs_mount_t	*mp;		/* file system mount structure */
 660	int		offset;		/* index of inode in chunk */
 661	xfs_agino_t	pagino;		/* parent's AG relative inode # */
 662	xfs_agnumber_t	pagno;		/* parent's AG number */
 663	xfs_inobt_rec_incore_t rec;	/* inode allocation record */
 664	xfs_agnumber_t	tagno;		/* testing allocation group number */
 665	xfs_btree_cur_t	*tcur;		/* temp cursor */
 666	xfs_inobt_rec_incore_t trec;	/* temp inode allocation record */
 667	struct xfs_perag *pag;
 668
 669
 670	if (*IO_agbp == NULL) {
 671		/*
 672		 * We do not have an agbp, so select an initial allocation
 673		 * group for inode allocation.
 674		 */
 675		agbp = xfs_ialloc_ag_select(tp, parent, mode, okalloc);
 676		/*
 677		 * Couldn't find an allocation group satisfying the
 678		 * criteria, give up.
 679		 */
 680		if (!agbp) {
 681			*inop = NULLFSINO;
 682			return 0;
 683		}
 684		agi = XFS_BUF_TO_AGI(agbp);
 685		ASSERT(agi->agi_magicnum == cpu_to_be32(XFS_AGI_MAGIC));
 686	} else {
 687		/*
 688		 * Continue where we left off before.  In this case, we
 689		 * know that the allocation group has free inodes.
 690		 */
 691		agbp = *IO_agbp;
 692		agi = XFS_BUF_TO_AGI(agbp);
 693		ASSERT(agi->agi_magicnum == cpu_to_be32(XFS_AGI_MAGIC));
 694		ASSERT(be32_to_cpu(agi->agi_freecount) > 0);
 695	}
 696	mp = tp->t_mountp;
 697	agcount = mp->m_sb.sb_agcount;
 698	agno = be32_to_cpu(agi->agi_seqno);
 699	tagno = agno;
 700	pagno = XFS_INO_TO_AGNO(mp, parent);
 701	pagino = XFS_INO_TO_AGINO(mp, parent);
 702
 703	/*
 704	 * If we have already hit the ceiling of inode blocks then clear
 705	 * okalloc so we scan all available agi structures for a free
 706	 * inode.
 707	 */
 708
 709	if (mp->m_maxicount &&
 710	    mp->m_sb.sb_icount + XFS_IALLOC_INODES(mp) > mp->m_maxicount) {
 711		noroom = 1;
 712		okalloc = 0;
 713	}
 714
 715	/*
 716	 * Loop until we find an allocation group that either has free inodes
 717	 * or in which we can allocate some inodes.  Iterate through the
 718	 * allocation groups upward, wrapping at the end.
 719	 */
 720	*alloc_done = B_FALSE;
 721	while (!agi->agi_freecount) {
 722		/*
 723		 * Don't do anything if we're not supposed to allocate
 724		 * any blocks, just go on to the next ag.
 725		 */
 726		if (okalloc) {
 727			/*
 728			 * Try to allocate some new inodes in the allocation
 729			 * group.
 730			 */
 731			if ((error = xfs_ialloc_ag_alloc(tp, agbp, &ialloced))) {
 732				xfs_trans_brelse(tp, agbp);
 733				if (error == ENOSPC) {
 734					*inop = NULLFSINO;
 735					return 0;
 736				} else
 737					return error;
 738			}
 739			if (ialloced) {
 740				/*
 741				 * We successfully allocated some inodes, return
 742				 * the current context to the caller so that it
 743				 * can commit the current transaction and call
 744				 * us again where we left off.
 745				 */
 746				ASSERT(be32_to_cpu(agi->agi_freecount) > 0);
 747				*alloc_done = B_TRUE;
 748				*IO_agbp = agbp;
 749				*inop = NULLFSINO;
 750				return 0;
 751			}
 752		}
 753		/*
 754		 * If it failed, give up on this ag.
 755		 */
 756		xfs_trans_brelse(tp, agbp);
 757		/*
 758		 * Go on to the next ag: get its ag header.
 759		 */
 760nextag:
 761		if (++tagno == agcount)
 762			tagno = 0;
 763		if (tagno == agno) {
 764			*inop = NULLFSINO;
 765			return noroom ? ENOSPC : 0;
 766		}
 767		pag = xfs_perag_get(mp, tagno);
 768		if (pag->pagi_inodeok == 0) {
 769			xfs_perag_put(pag);
 770			goto nextag;
 771		}
 772		error = xfs_ialloc_read_agi(mp, tp, tagno, &agbp);
 773		xfs_perag_put(pag);
 774		if (error)
 775			goto nextag;
 776		agi = XFS_BUF_TO_AGI(agbp);
 777		ASSERT(agi->agi_magicnum == cpu_to_be32(XFS_AGI_MAGIC));
 778	}
 779	/*
 780	 * Here with an allocation group that has a free inode.
 781	 * Reset agno since we may have chosen a new ag in the
 782	 * loop above.
 783	 */
 784	agno = tagno;
 785	*IO_agbp = NULL;
 786	pag = xfs_perag_get(mp, agno);
 787
 788 restart_pagno:
 789	cur = xfs_inobt_init_cursor(mp, tp, agbp, be32_to_cpu(agi->agi_seqno));
 790	/*
 791	 * If pagino is 0 (this is the root inode allocation) use newino.
 792	 * This must work because we've just allocated some.
 793	 */
 794	if (!pagino)
 795		pagino = be32_to_cpu(agi->agi_newino);
 796
 797	error = xfs_check_agi_freecount(cur, agi);
 798	if (error)
 799		goto error0;
 800
 801	/*
 802	 * If in the same AG as the parent, try to get near the parent.
 803	 */
 804	if (pagno == agno) {
 805		int		doneleft;	/* done, to the left */
 806		int		doneright;	/* done, to the right */
 807		int		searchdistance = 10;
 808
 809		error = xfs_inobt_lookup(cur, pagino, XFS_LOOKUP_LE, &i);
 810		if (error)
 811			goto error0;
 812		XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
 813
 814		error = xfs_inobt_get_rec(cur, &rec, &j);
 815		if (error)
 816			goto error0;
 817		XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
 818
 819		if (rec.ir_freecount > 0) {
 820			/*
 821			 * Found a free inode in the same chunk
 822			 * as the parent, done.
 823			 */
 824			goto alloc_inode;
 825		}
 826
 827
 828		/*
 829		 * In the same AG as parent, but parent's chunk is full.
 830		 */
 831
 832		/* duplicate the cursor, search left & right simultaneously */
 833		error = xfs_btree_dup_cursor(cur, &tcur);
 834		if (error)
 835			goto error0;
 836
 837		/*
 838		 * Skip to last blocks looked up if same parent inode.
 839		 */
 840		if (pagino != NULLAGINO &&
 841		    pag->pagl_pagino == pagino &&
 842		    pag->pagl_leftrec != NULLAGINO &&
 843		    pag->pagl_rightrec != NULLAGINO) {
 844			error = xfs_ialloc_get_rec(tcur, pag->pagl_leftrec,
 845						   &trec, &doneleft, 1);
 846			if (error)
 847				goto error1;
 848
 849			error = xfs_ialloc_get_rec(cur, pag->pagl_rightrec,
 850						   &rec, &doneright, 0);
 851			if (error)
 852				goto error1;
 853		} else {
 854			/* search left with tcur, back up 1 record */
 855			error = xfs_ialloc_next_rec(tcur, &trec, &doneleft, 1);
 856			if (error)
 857				goto error1;
 858
 859			/* search right with cur, go forward 1 record. */
 860			error = xfs_ialloc_next_rec(cur, &rec, &doneright, 0);
 861			if (error)
 862				goto error1;
 863		}
 864
 865		/*
 866		 * Loop until we find an inode chunk with a free inode.
 867		 */
 868		while (!doneleft || !doneright) {
 869			int	useleft;  /* using left inode chunk this time */
 870
 871			if (!--searchdistance) {
 872				/*
 873				 * Not in range - save last search
 874				 * location and allocate a new inode
 875				 */
 876				xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
 877				pag->pagl_leftrec = trec.ir_startino;
 878				pag->pagl_rightrec = rec.ir_startino;
 879				pag->pagl_pagino = pagino;
 880				goto newino;
 881			}
 882
 883			/* figure out the closer block if both are valid. */
 884			if (!doneleft && !doneright) {
 885				useleft = pagino -
 886				 (trec.ir_startino + XFS_INODES_PER_CHUNK - 1) <
 887				  rec.ir_startino - pagino;
 888			} else {
 889				useleft = !doneleft;
 890			}
 891
 892			/* free inodes to the left? */
 893			if (useleft && trec.ir_freecount) {
 894				rec = trec;
 895				xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
 896				cur = tcur;
 897
 898				pag->pagl_leftrec = trec.ir_startino;
 899				pag->pagl_rightrec = rec.ir_startino;
 900				pag->pagl_pagino = pagino;
 901				goto alloc_inode;
 902			}
 903
 904			/* free inodes to the right? */
 905			if (!useleft && rec.ir_freecount) {
 906				xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
 907
 908				pag->pagl_leftrec = trec.ir_startino;
 909				pag->pagl_rightrec = rec.ir_startino;
 910				pag->pagl_pagino = pagino;
 911				goto alloc_inode;
 912			}
 913
 914			/* get next record to check */
 915			if (useleft) {
 916				error = xfs_ialloc_next_rec(tcur, &trec,
 917								 &doneleft, 1);
 918			} else {
 919				error = xfs_ialloc_next_rec(cur, &rec,
 920								 &doneright, 0);
 921			}
 922			if (error)
 923				goto error1;
 924		}
 925
 926		/*
 927		 * We've reached the end of the btree. because
 928		 * we are only searching a small chunk of the
 929		 * btree each search, there is obviously free
 930		 * inodes closer to the parent inode than we
 931		 * are now. restart the search again.
 932		 */
 933		pag->pagl_pagino = NULLAGINO;
 934		pag->pagl_leftrec = NULLAGINO;
 935		pag->pagl_rightrec = NULLAGINO;
 936		xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
 937		xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
 938		goto restart_pagno;
 939	}
 940
 941	/*
 942	 * In a different AG from the parent.
 943	 * See if the most recently allocated block has any free.
 944	 */
 945newino:
 946	if (agi->agi_newino != cpu_to_be32(NULLAGINO)) {
 947		error = xfs_inobt_lookup(cur, be32_to_cpu(agi->agi_newino),
 948					 XFS_LOOKUP_EQ, &i);
 949		if (error)
 950			goto error0;
 951
 952		if (i == 1) {
 953			error = xfs_inobt_get_rec(cur, &rec, &j);
 954			if (error)
 955				goto error0;
 956
 957			if (j == 1 && rec.ir_freecount > 0) {
 958				/*
 959				 * The last chunk allocated in the group
 960				 * still has a free inode.
 961				 */
 962				goto alloc_inode;
 963			}
 964		}
 965	}
 966
 967	/*
 968	 * None left in the last group, search the whole AG
 969	 */
 970	error = xfs_inobt_lookup(cur, 0, XFS_LOOKUP_GE, &i);
 971	if (error)
 972		goto error0;
 973	XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
 974
 975	for (;;) {
 976		error = xfs_inobt_get_rec(cur, &rec, &i);
 977		if (error)
 978			goto error0;
 979		XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
 980		if (rec.ir_freecount > 0)
 981			break;
 982		error = xfs_btree_increment(cur, 0, &i);
 983		if (error)
 984			goto error0;
 985		XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
 986	}
 987
 988alloc_inode:
 989	offset = xfs_ialloc_find_free(&rec.ir_free);
 990	ASSERT(offset >= 0);
 991	ASSERT(offset < XFS_INODES_PER_CHUNK);
 992	ASSERT((XFS_AGINO_TO_OFFSET(mp, rec.ir_startino) %
 993				   XFS_INODES_PER_CHUNK) == 0);
 994	ino = XFS_AGINO_TO_INO(mp, agno, rec.ir_startino + offset);
 995	rec.ir_free &= ~XFS_INOBT_MASK(offset);
 996	rec.ir_freecount--;
 997	error = xfs_inobt_update(cur, &rec);
 998	if (error)
 999		goto error0;
1000	be32_add_cpu(&agi->agi_freecount, -1);
1001	xfs_ialloc_log_agi(tp, agbp, XFS_AGI_FREECOUNT);
1002	pag->pagi_freecount--;
1003
1004	error = xfs_check_agi_freecount(cur, agi);
1005	if (error)
1006		goto error0;
1007
1008	xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
1009	xfs_trans_mod_sb(tp, XFS_TRANS_SB_IFREE, -1);
1010	xfs_perag_put(pag);
1011	*inop = ino;
1012	return 0;
1013error1:
1014	xfs_btree_del_cursor(tcur, XFS_BTREE_ERROR);
1015error0:
1016	xfs_btree_del_cursor(cur, XFS_BTREE_ERROR);
1017	xfs_perag_put(pag);
1018	return error;
1019}
1020
1021/*
1022 * Free disk inode.  Carefully avoids touching the incore inode, all
1023 * manipulations incore are the caller's responsibility.
1024 * The on-disk inode is not changed by this operation, only the
1025 * btree (free inode mask) is changed.
1026 */
1027int
1028xfs_difree(
1029	xfs_trans_t	*tp,		/* transaction pointer */
1030	xfs_ino_t	inode,		/* inode to be freed */
1031	xfs_bmap_free_t	*flist,		/* extents to free */
1032	int		*delete,	/* set if inode cluster was deleted */
1033	xfs_ino_t	*first_ino)	/* first inode in deleted cluster */
1034{
1035	/* REFERENCED */
1036	xfs_agblock_t	agbno;	/* block number containing inode */
1037	xfs_buf_t	*agbp;	/* buffer containing allocation group header */
1038	xfs_agino_t	agino;	/* inode number relative to allocation group */
1039	xfs_agnumber_t	agno;	/* allocation group number */
1040	xfs_agi_t	*agi;	/* allocation group header */
1041	xfs_btree_cur_t	*cur;	/* inode btree cursor */
1042	int		error;	/* error return value */
1043	int		i;	/* result code */
1044	int		ilen;	/* inodes in an inode cluster */
1045	xfs_mount_t	*mp;	/* mount structure for filesystem */
1046	int		off;	/* offset of inode in inode chunk */
1047	xfs_inobt_rec_incore_t rec;	/* btree record */
1048	struct xfs_perag *pag;
1049
1050	mp = tp->t_mountp;
1051
1052	/*
1053	 * Break up inode number into its components.
1054	 */
1055	agno = XFS_INO_TO_AGNO(mp, inode);
1056	if (agno >= mp->m_sb.sb_agcount)  {
1057		xfs_warn(mp, "%s: agno >= mp->m_sb.sb_agcount (%d >= %d).",
1058			__func__, agno, mp->m_sb.sb_agcount);
1059		ASSERT(0);
1060		return XFS_ERROR(EINVAL);
1061	}
1062	agino = XFS_INO_TO_AGINO(mp, inode);
1063	if (inode != XFS_AGINO_TO_INO(mp, agno, agino))  {
1064		xfs_warn(mp, "%s: inode != XFS_AGINO_TO_INO() (%llu != %llu).",
1065			__func__, (unsigned long long)inode,
1066			(unsigned long long)XFS_AGINO_TO_INO(mp, agno, agino));
1067		ASSERT(0);
1068		return XFS_ERROR(EINVAL);
1069	}
1070	agbno = XFS_AGINO_TO_AGBNO(mp, agino);
1071	if (agbno >= mp->m_sb.sb_agblocks)  {
1072		xfs_warn(mp, "%s: agbno >= mp->m_sb.sb_agblocks (%d >= %d).",
1073			__func__, agbno, mp->m_sb.sb_agblocks);
1074		ASSERT(0);
1075		return XFS_ERROR(EINVAL);
1076	}
1077	/*
1078	 * Get the allocation group header.
1079	 */
1080	error = xfs_ialloc_read_agi(mp, tp, agno, &agbp);
1081	if (error) {
1082		xfs_warn(mp, "%s: xfs_ialloc_read_agi() returned error %d.",
1083			__func__, error);
1084		return error;
1085	}
1086	agi = XFS_BUF_TO_AGI(agbp);
1087	ASSERT(agi->agi_magicnum == cpu_to_be32(XFS_AGI_MAGIC));
1088	ASSERT(agbno < be32_to_cpu(agi->agi_length));
1089	/*
1090	 * Initialize the cursor.
1091	 */
1092	cur = xfs_inobt_init_cursor(mp, tp, agbp, agno);
1093
1094	error = xfs_check_agi_freecount(cur, agi);
1095	if (error)
1096		goto error0;
1097
1098	/*
1099	 * Look for the entry describing this inode.
1100	 */
1101	if ((error = xfs_inobt_lookup(cur, agino, XFS_LOOKUP_LE, &i))) {
1102		xfs_warn(mp, "%s: xfs_inobt_lookup() returned error %d.",
1103			__func__, error);
1104		goto error0;
1105	}
1106	XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1107	error = xfs_inobt_get_rec(cur, &rec, &i);
1108	if (error) {
1109		xfs_warn(mp, "%s: xfs_inobt_get_rec() returned error %d.",
1110			__func__, error);
1111		goto error0;
1112	}
1113	XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
1114	/*
1115	 * Get the offset in the inode chunk.
1116	 */
1117	off = agino - rec.ir_startino;
1118	ASSERT(off >= 0 && off < XFS_INODES_PER_CHUNK);
1119	ASSERT(!(rec.ir_free & XFS_INOBT_MASK(off)));
1120	/*
1121	 * Mark the inode free & increment the count.
1122	 */
1123	rec.ir_free |= XFS_INOBT_MASK(off);
1124	rec.ir_freecount++;
1125
1126	/*
1127	 * When an inode cluster is free, it becomes eligible for removal
1128	 */
1129	if (!(mp->m_flags & XFS_MOUNT_IKEEP) &&
1130	    (rec.ir_freecount == XFS_IALLOC_INODES(mp))) {
1131
1132		*delete = 1;
1133		*first_ino = XFS_AGINO_TO_INO(mp, agno, rec.ir_startino);
1134
1135		/*
1136		 * Remove the inode cluster from the AGI B+Tree, adjust the
1137		 * AGI and Superblock inode counts, and mark the disk space
1138		 * to be freed when the transaction is committed.
1139		 */
1140		ilen = XFS_IALLOC_INODES(mp);
1141		be32_add_cpu(&agi->agi_count, -ilen);
1142		be32_add_cpu(&agi->agi_freecount, -(ilen - 1));
1143		xfs_ialloc_log_agi(tp, agbp, XFS_AGI_COUNT | XFS_AGI_FREECOUNT);
1144		pag = xfs_perag_get(mp, agno);
1145		pag->pagi_freecount -= ilen - 1;
1146		xfs_perag_put(pag);
1147		xfs_trans_mod_sb(tp, XFS_TRANS_SB_ICOUNT, -ilen);
1148		xfs_trans_mod_sb(tp, XFS_TRANS_SB_IFREE, -(ilen - 1));
1149
1150		if ((error = xfs_btree_delete(cur, &i))) {
1151			xfs_warn(mp, "%s: xfs_btree_delete returned error %d.",
1152				__func__, error);
1153			goto error0;
1154		}
1155
1156		xfs_bmap_add_free(XFS_AGB_TO_FSB(mp,
1157				agno, XFS_INO_TO_AGBNO(mp,rec.ir_startino)),
1158				XFS_IALLOC_BLOCKS(mp), flist, mp);
1159	} else {
1160		*delete = 0;
1161
1162		error = xfs_inobt_update(cur, &rec);
1163		if (error) {
1164			xfs_warn(mp, "%s: xfs_inobt_update returned error %d.",
1165				__func__, error);
1166			goto error0;
1167		}
1168
1169		/* 
1170		 * Change the inode free counts and log the ag/sb changes.
1171		 */
1172		be32_add_cpu(&agi->agi_freecount, 1);
1173		xfs_ialloc_log_agi(tp, agbp, XFS_AGI_FREECOUNT);
1174		pag = xfs_perag_get(mp, agno);
1175		pag->pagi_freecount++;
1176		xfs_perag_put(pag);
1177		xfs_trans_mod_sb(tp, XFS_TRANS_SB_IFREE, 1);
1178	}
1179
1180	error = xfs_check_agi_freecount(cur, agi);
1181	if (error)
1182		goto error0;
1183
1184	xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
1185	return 0;
1186
1187error0:
1188	xfs_btree_del_cursor(cur, XFS_BTREE_ERROR);
1189	return error;
1190}
1191
1192STATIC int
1193xfs_imap_lookup(
1194	struct xfs_mount	*mp,
1195	struct xfs_trans	*tp,
1196	xfs_agnumber_t		agno,
1197	xfs_agino_t		agino,
1198	xfs_agblock_t		agbno,
1199	xfs_agblock_t		*chunk_agbno,
1200	xfs_agblock_t		*offset_agbno,
1201	int			flags)
1202{
1203	struct xfs_inobt_rec_incore rec;
1204	struct xfs_btree_cur	*cur;
1205	struct xfs_buf		*agbp;
1206	int			error;
1207	int			i;
1208
1209	error = xfs_ialloc_read_agi(mp, tp, agno, &agbp);
1210	if (error) {
1211		xfs_alert(mp,
1212			"%s: xfs_ialloc_read_agi() returned error %d, agno %d",
1213			__func__, error, agno);
1214		return error;
1215	}
1216
1217	/*
1218	 * Lookup the inode record for the given agino. If the record cannot be
1219	 * found, then it's an invalid inode number and we should abort. Once
1220	 * we have a record, we need to ensure it contains the inode number
1221	 * we are looking up.
1222	 */
1223	cur = xfs_inobt_init_cursor(mp, tp, agbp, agno);
1224	error = xfs_inobt_lookup(cur, agino, XFS_LOOKUP_LE, &i);
1225	if (!error) {
1226		if (i)
1227			error = xfs_inobt_get_rec(cur, &rec, &i);
1228		if (!error && i == 0)
1229			error = EINVAL;
1230	}
1231
1232	xfs_trans_brelse(tp, agbp);
1233	xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
1234	if (error)
1235		return error;
1236
1237	/* check that the returned record contains the required inode */
1238	if (rec.ir_startino > agino ||
1239	    rec.ir_startino + XFS_IALLOC_INODES(mp) <= agino)
1240		return EINVAL;
1241
1242	/* for untrusted inodes check it is allocated first */
1243	if ((flags & XFS_IGET_UNTRUSTED) &&
1244	    (rec.ir_free & XFS_INOBT_MASK(agino - rec.ir_startino)))
1245		return EINVAL;
1246
1247	*chunk_agbno = XFS_AGINO_TO_AGBNO(mp, rec.ir_startino);
1248	*offset_agbno = agbno - *chunk_agbno;
1249	return 0;
1250}
1251
1252/*
1253 * Return the location of the inode in imap, for mapping it into a buffer.
1254 */
1255int
1256xfs_imap(
1257	xfs_mount_t	 *mp,	/* file system mount structure */
1258	xfs_trans_t	 *tp,	/* transaction pointer */
1259	xfs_ino_t	ino,	/* inode to locate */
1260	struct xfs_imap	*imap,	/* location map structure */
1261	uint		flags)	/* flags for inode btree lookup */
1262{
1263	xfs_agblock_t	agbno;	/* block number of inode in the alloc group */
1264	xfs_agino_t	agino;	/* inode number within alloc group */
1265	xfs_agnumber_t	agno;	/* allocation group number */
1266	int		blks_per_cluster; /* num blocks per inode cluster */
1267	xfs_agblock_t	chunk_agbno;	/* first block in inode chunk */
1268	xfs_agblock_t	cluster_agbno;	/* first block in inode cluster */
1269	int		error;	/* error code */
1270	int		offset;	/* index of inode in its buffer */
1271	int		offset_agbno;	/* blks from chunk start to inode */
1272
1273	ASSERT(ino != NULLFSINO);
1274
1275	/*
1276	 * Split up the inode number into its parts.
1277	 */
1278	agno = XFS_INO_TO_AGNO(mp, ino);
1279	agino = XFS_INO_TO_AGINO(mp, ino);
1280	agbno = XFS_AGINO_TO_AGBNO(mp, agino);
1281	if (agno >= mp->m_sb.sb_agcount || agbno >= mp->m_sb.sb_agblocks ||
1282	    ino != XFS_AGINO_TO_INO(mp, agno, agino)) {
1283#ifdef DEBUG
1284		/*
1285		 * Don't output diagnostic information for untrusted inodes
1286		 * as they can be invalid without implying corruption.
1287		 */
1288		if (flags & XFS_IGET_UNTRUSTED)
1289			return XFS_ERROR(EINVAL);
1290		if (agno >= mp->m_sb.sb_agcount) {
1291			xfs_alert(mp,
1292				"%s: agno (%d) >= mp->m_sb.sb_agcount (%d)",
1293				__func__, agno, mp->m_sb.sb_agcount);
1294		}
1295		if (agbno >= mp->m_sb.sb_agblocks) {
1296			xfs_alert(mp,
1297		"%s: agbno (0x%llx) >= mp->m_sb.sb_agblocks (0x%lx)",
1298				__func__, (unsigned long long)agbno,
1299				(unsigned long)mp->m_sb.sb_agblocks);
1300		}
1301		if (ino != XFS_AGINO_TO_INO(mp, agno, agino)) {
1302			xfs_alert(mp,
1303		"%s: ino (0x%llx) != XFS_AGINO_TO_INO() (0x%llx)",
1304				__func__, ino,
1305				XFS_AGINO_TO_INO(mp, agno, agino));
1306		}
1307		xfs_stack_trace();
1308#endif /* DEBUG */
1309		return XFS_ERROR(EINVAL);
1310	}
1311
1312	blks_per_cluster = XFS_INODE_CLUSTER_SIZE(mp) >> mp->m_sb.sb_blocklog;
1313
1314	/*
1315	 * For bulkstat and handle lookups, we have an untrusted inode number
1316	 * that we have to verify is valid. We cannot do this just by reading
1317	 * the inode buffer as it may have been unlinked and removed leaving
1318	 * inodes in stale state on disk. Hence we have to do a btree lookup
1319	 * in all cases where an untrusted inode number is passed.
1320	 */
1321	if (flags & XFS_IGET_UNTRUSTED) {
1322		error = xfs_imap_lookup(mp, tp, agno, agino, agbno,
1323					&chunk_agbno, &offset_agbno, flags);
1324		if (error)
1325			return error;
1326		goto out_map;
1327	}
1328
1329	/*
1330	 * If the inode cluster size is the same as the blocksize or
1331	 * smaller we get to the buffer by simple arithmetics.
1332	 */
1333	if (XFS_INODE_CLUSTER_SIZE(mp) <= mp->m_sb.sb_blocksize) {
1334		offset = XFS_INO_TO_OFFSET(mp, ino);
1335		ASSERT(offset < mp->m_sb.sb_inopblock);
1336
1337		imap->im_blkno = XFS_AGB_TO_DADDR(mp, agno, agbno);
1338		imap->im_len = XFS_FSB_TO_BB(mp, 1);
1339		imap->im_boffset = (ushort)(offset << mp->m_sb.sb_inodelog);
1340		return 0;
1341	}
1342
1343	/*
1344	 * If the inode chunks are aligned then use simple maths to
1345	 * find the location. Otherwise we have to do a btree
1346	 * lookup to find the location.
1347	 */
1348	if (mp->m_inoalign_mask) {
1349		offset_agbno = agbno & mp->m_inoalign_mask;
1350		chunk_agbno = agbno - offset_agbno;
1351	} else {
1352		error = xfs_imap_lookup(mp, tp, agno, agino, agbno,
1353					&chunk_agbno, &offset_agbno, flags);
1354		if (error)
1355			return error;
1356	}
1357
1358out_map:
1359	ASSERT(agbno >= chunk_agbno);
1360	cluster_agbno = chunk_agbno +
1361		((offset_agbno / blks_per_cluster) * blks_per_cluster);
1362	offset = ((agbno - cluster_agbno) * mp->m_sb.sb_inopblock) +
1363		XFS_INO_TO_OFFSET(mp, ino);
1364
1365	imap->im_blkno = XFS_AGB_TO_DADDR(mp, agno, cluster_agbno);
1366	imap->im_len = XFS_FSB_TO_BB(mp, blks_per_cluster);
1367	imap->im_boffset = (ushort)(offset << mp->m_sb.sb_inodelog);
1368
1369	/*
1370	 * If the inode number maps to a block outside the bounds
1371	 * of the file system then return NULL rather than calling
1372	 * read_buf and panicing when we get an error from the
1373	 * driver.
1374	 */
1375	if ((imap->im_blkno + imap->im_len) >
1376	    XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks)) {
1377		xfs_alert(mp,
1378	"%s: (im_blkno (0x%llx) + im_len (0x%llx)) > sb_dblocks (0x%llx)",
1379			__func__, (unsigned long long) imap->im_blkno,
1380			(unsigned long long) imap->im_len,
1381			XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks));
1382		return XFS_ERROR(EINVAL);
1383	}
1384	return 0;
1385}
1386
1387/*
1388 * Compute and fill in value of m_in_maxlevels.
1389 */
1390void
1391xfs_ialloc_compute_maxlevels(
1392	xfs_mount_t	*mp)		/* file system mount structure */
1393{
1394	int		level;
1395	uint		maxblocks;
1396	uint		maxleafents;
1397	int		minleafrecs;
1398	int		minnoderecs;
1399
1400	maxleafents = (1LL << XFS_INO_AGINO_BITS(mp)) >>
1401		XFS_INODES_PER_CHUNK_LOG;
1402	minleafrecs = mp->m_alloc_mnr[0];
1403	minnoderecs = mp->m_alloc_mnr[1];
1404	maxblocks = (maxleafents + minleafrecs - 1) / minleafrecs;
1405	for (level = 1; maxblocks > 1; level++)
1406		maxblocks = (maxblocks + minnoderecs - 1) / minnoderecs;
1407	mp->m_in_maxlevels = level;
1408}
1409
1410/*
1411 * Log specified fields for the ag hdr (inode section)
1412 */
1413void
1414xfs_ialloc_log_agi(
1415	xfs_trans_t	*tp,		/* transaction pointer */
1416	xfs_buf_t	*bp,		/* allocation group header buffer */
1417	int		fields)		/* bitmask of fields to log */
1418{
1419	int			first;		/* first byte number */
1420	int			last;		/* last byte number */
1421	static const short	offsets[] = {	/* field starting offsets */
1422					/* keep in sync with bit definitions */
1423		offsetof(xfs_agi_t, agi_magicnum),
1424		offsetof(xfs_agi_t, agi_versionnum),
1425		offsetof(xfs_agi_t, agi_seqno),
1426		offsetof(xfs_agi_t, agi_length),
1427		offsetof(xfs_agi_t, agi_count),
1428		offsetof(xfs_agi_t, agi_root),
1429		offsetof(xfs_agi_t, agi_level),
1430		offsetof(xfs_agi_t, agi_freecount),
1431		offsetof(xfs_agi_t, agi_newino),
1432		offsetof(xfs_agi_t, agi_dirino),
1433		offsetof(xfs_agi_t, agi_unlinked),
1434		sizeof(xfs_agi_t)
1435	};
1436#ifdef DEBUG
1437	xfs_agi_t		*agi;	/* allocation group header */
1438
1439	agi = XFS_BUF_TO_AGI(bp);
1440	ASSERT(agi->agi_magicnum == cpu_to_be32(XFS_AGI_MAGIC));
1441#endif
1442	/*
1443	 * Compute byte offsets for the first and last fields.
1444	 */
1445	xfs_btree_offsets(fields, offsets, XFS_AGI_NUM_BITS, &first, &last);
1446	/*
1447	 * Log the allocation group inode header buffer.
1448	 */
1449	xfs_trans_log_buf(tp, bp, first, last);
1450}
1451
1452#ifdef DEBUG
1453STATIC void
1454xfs_check_agi_unlinked(
1455	struct xfs_agi		*agi)
1456{
1457	int			i;
1458
1459	for (i = 0; i < XFS_AGI_UNLINKED_BUCKETS; i++)
1460		ASSERT(agi->agi_unlinked[i]);
1461}
1462#else
1463#define xfs_check_agi_unlinked(agi)
1464#endif
1465
1466/*
1467 * Read in the allocation group header (inode allocation section)
1468 */
1469int
1470xfs_read_agi(
1471	struct xfs_mount	*mp,	/* file system mount structure */
1472	struct xfs_trans	*tp,	/* transaction pointer */
1473	xfs_agnumber_t		agno,	/* allocation group number */
1474	struct xfs_buf		**bpp)	/* allocation group hdr buf */
1475{
1476	struct xfs_agi		*agi;	/* allocation group header */
1477	int			agi_ok;	/* agi is consistent */
1478	int			error;
1479
1480	ASSERT(agno != NULLAGNUMBER);
1481
1482	error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp,
1483			XFS_AG_DADDR(mp, agno, XFS_AGI_DADDR(mp)),
1484			XFS_FSS_TO_BB(mp, 1), 0, bpp);
1485	if (error)
1486		return error;
1487
1488	ASSERT(!xfs_buf_geterror(*bpp));
1489	agi = XFS_BUF_TO_AGI(*bpp);
1490
1491	/*
1492	 * Validate the magic number of the agi block.
1493	 */
1494	agi_ok = agi->agi_magicnum == cpu_to_be32(XFS_AGI_MAGIC) &&
1495		XFS_AGI_GOOD_VERSION(be32_to_cpu(agi->agi_versionnum)) &&
1496		be32_to_cpu(agi->agi_seqno) == agno;
1497	if (unlikely(XFS_TEST_ERROR(!agi_ok, mp, XFS_ERRTAG_IALLOC_READ_AGI,
1498			XFS_RANDOM_IALLOC_READ_AGI))) {
1499		XFS_CORRUPTION_ERROR("xfs_read_agi", XFS_ERRLEVEL_LOW,
1500				     mp, agi);
1501		xfs_trans_brelse(tp, *bpp);
1502		return XFS_ERROR(EFSCORRUPTED);
1503	}
1504
1505	XFS_BUF_SET_VTYPE_REF(*bpp, B_FS_AGI, XFS_AGI_REF);
1506
1507	xfs_check_agi_unlinked(agi);
1508	return 0;
1509}
1510
1511int
1512xfs_ialloc_read_agi(
1513	struct xfs_mount	*mp,	/* file system mount structure */
1514	struct xfs_trans	*tp,	/* transaction pointer */
1515	xfs_agnumber_t		agno,	/* allocation group number */
1516	struct xfs_buf		**bpp)	/* allocation group hdr buf */
1517{
1518	struct xfs_agi		*agi;	/* allocation group header */
1519	struct xfs_perag	*pag;	/* per allocation group data */
1520	int			error;
1521
1522	error = xfs_read_agi(mp, tp, agno, bpp);
1523	if (error)
1524		return error;
1525
1526	agi = XFS_BUF_TO_AGI(*bpp);
1527	pag = xfs_perag_get(mp, agno);
1528	if (!pag->pagi_init) {
1529		pag->pagi_freecount = be32_to_cpu(agi->agi_freecount);
1530		pag->pagi_count = be32_to_cpu(agi->agi_count);
1531		pag->pagi_init = 1;
1532	}
1533
1534	/*
1535	 * It's possible for these to be out of sync if
1536	 * we are in the middle of a forced shutdown.
1537	 */
1538	ASSERT(pag->pagi_freecount == be32_to_cpu(agi->agi_freecount) ||
1539		XFS_FORCED_SHUTDOWN(mp));
1540	xfs_perag_put(pag);
1541	return 0;
1542}
1543
1544/*
1545 * Read in the agi to initialise the per-ag data in the mount structure
1546 */
1547int
1548xfs_ialloc_pagi_init(
1549	xfs_mount_t	*mp,		/* file system mount structure */
1550	xfs_trans_t	*tp,		/* transaction pointer */
1551	xfs_agnumber_t	agno)		/* allocation group number */
1552{
1553	xfs_buf_t	*bp = NULL;
1554	int		error;
1555
1556	error = xfs_ialloc_read_agi(mp, tp, agno, &bp);
1557	if (error)
1558		return error;
1559	if (bp)
1560		xfs_trans_brelse(tp, bp);
1561	return 0;
1562}