1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
   4 * All Rights Reserved.
   5 */
   6#include "xfs.h"
   7#include "xfs_fs.h"
   8#include "xfs_shared.h"
   9#include "xfs_format.h"
  10#include "xfs_log_format.h"
  11#include "xfs_trans_resv.h"
  12#include "xfs_bit.h"
  13#include "xfs_mount.h"
  14#include "xfs_inode.h"
  15#include "xfs_bmap.h"
  16#include "xfs_bmap_btree.h"
  17#include "xfs_trans.h"
  18#include "xfs_trans_space.h"
  19#include "xfs_icache.h"
  20#include "xfs_rtalloc.h"
  21
  22
  23/*
  24 * Read and return the summary information for a given extent size,
  25 * bitmap block combination.
  26 * Keeps track of a current summary block, so we don't keep reading
  27 * it from the buffer cache.
  28 */
  29static int
  30xfs_rtget_summary(
  31	xfs_mount_t	*mp,		/* file system mount structure */
  32	xfs_trans_t	*tp,		/* transaction pointer */
  33	int		log,		/* log2 of extent size */
  34	xfs_rtblock_t	bbno,		/* bitmap block number */
  35	xfs_buf_t	**rbpp,		/* in/out: summary block buffer */
  36	xfs_fsblock_t	*rsb,		/* in/out: summary block number */
  37	xfs_suminfo_t	*sum)		/* out: summary info for this block */
  38{
  39	return xfs_rtmodify_summary_int(mp, tp, log, bbno, 0, rbpp, rsb, sum);
  40}
  41
  42/*
  43 * Return whether there are any free extents in the size range given
  44 * by low and high, for the bitmap block bbno.
  45 */
  46STATIC int				/* error */
  47xfs_rtany_summary(
  48	xfs_mount_t	*mp,		/* file system mount structure */
  49	xfs_trans_t	*tp,		/* transaction pointer */
  50	int		low,		/* low log2 extent size */
  51	int		high,		/* high log2 extent size */
  52	xfs_rtblock_t	bbno,		/* bitmap block number */
  53	xfs_buf_t	**rbpp,		/* in/out: summary block buffer */
  54	xfs_fsblock_t	*rsb,		/* in/out: summary block number */
  55	int		*stat)		/* out: any good extents here? */
  56{
  57	int		error;		/* error value */
  58	int		log;		/* loop counter, log2 of ext. size */
  59	xfs_suminfo_t	sum;		/* summary data */
  60
  61	/* There are no extents at levels < m_rsum_cache[bbno]. */
  62	if (mp->m_rsum_cache && low < mp->m_rsum_cache[bbno])
  63		low = mp->m_rsum_cache[bbno];
  64
  65	/*
  66	 * Loop over logs of extent sizes.
  67	 */
  68	for (log = low; log <= high; log++) {
  69		/*
  70		 * Get one summary datum.
  71		 */
  72		error = xfs_rtget_summary(mp, tp, log, bbno, rbpp, rsb, &sum);
  73		if (error) {
  74			return error;
  75		}
  76		/*
  77		 * If there are any, return success.
  78		 */
  79		if (sum) {
  80			*stat = 1;
  81			goto out;
  82		}
  83	}
  84	/*
  85	 * Found nothing, return failure.
  86	 */
  87	*stat = 0;
  88out:
  89	/* There were no extents at levels < log. */
  90	if (mp->m_rsum_cache && log > mp->m_rsum_cache[bbno])
  91		mp->m_rsum_cache[bbno] = log;
  92	return 0;
  93}
  94
  95
  96/*
  97 * Copy and transform the summary file, given the old and new
  98 * parameters in the mount structures.
  99 */
 100STATIC int				/* error */
 101xfs_rtcopy_summary(
 102	xfs_mount_t	*omp,		/* old file system mount point */
 103	xfs_mount_t	*nmp,		/* new file system mount point */
 104	xfs_trans_t	*tp)		/* transaction pointer */
 105{
 106	xfs_rtblock_t	bbno;		/* bitmap block number */
 107	xfs_buf_t	*bp;		/* summary buffer */
 108	int		error;		/* error return value */
 109	int		log;		/* summary level number (log length) */
 110	xfs_suminfo_t	sum;		/* summary data */
 111	xfs_fsblock_t	sumbno;		/* summary block number */
 112
 113	bp = NULL;
 114	for (log = omp->m_rsumlevels - 1; log >= 0; log--) {
 115		for (bbno = omp->m_sb.sb_rbmblocks - 1;
 116		     (xfs_srtblock_t)bbno >= 0;
 117		     bbno--) {
 118			error = xfs_rtget_summary(omp, tp, log, bbno, &bp,
 119				&sumbno, &sum);
 120			if (error)
 121				return error;
 122			if (sum == 0)
 123				continue;
 124			error = xfs_rtmodify_summary(omp, tp, log, bbno, -sum,
 125				&bp, &sumbno);
 126			if (error)
 127				return error;
 128			error = xfs_rtmodify_summary(nmp, tp, log, bbno, sum,
 129				&bp, &sumbno);
 130			if (error)
 131				return error;
 132			ASSERT(sum > 0);
 133		}
 134	}
 135	return 0;
 136}
 137/*
 138 * Mark an extent specified by start and len allocated.
 139 * Updates all the summary information as well as the bitmap.
 140 */
 141STATIC int				/* error */
 142xfs_rtallocate_range(
 143	xfs_mount_t	*mp,		/* file system mount point */
 144	xfs_trans_t	*tp,		/* transaction pointer */
 145	xfs_rtblock_t	start,		/* start block to allocate */
 146	xfs_extlen_t	len,		/* length to allocate */
 147	xfs_buf_t	**rbpp,		/* in/out: summary block buffer */
 148	xfs_fsblock_t	*rsb)		/* in/out: summary block number */
 149{
 150	xfs_rtblock_t	end;		/* end of the allocated extent */
 151	int		error;		/* error value */
 152	xfs_rtblock_t	postblock = 0;	/* first block allocated > end */
 153	xfs_rtblock_t	preblock = 0;	/* first block allocated < start */
 154
 155	end = start + len - 1;
 156	/*
 157	 * Assume we're allocating out of the middle of a free extent.
 158	 * We need to find the beginning and end of the extent so we can
 159	 * properly update the summary.
 160	 */
 161	error = xfs_rtfind_back(mp, tp, start, 0, &preblock);
 162	if (error) {
 163		return error;
 164	}
 165	/*
 166	 * Find the next allocated block (end of free extent).
 167	 */
 168	error = xfs_rtfind_forw(mp, tp, end, mp->m_sb.sb_rextents - 1,
 169		&postblock);
 170	if (error) {
 171		return error;
 172	}
 173	/*
 174	 * Decrement the summary information corresponding to the entire
 175	 * (old) free extent.
 176	 */
 177	error = xfs_rtmodify_summary(mp, tp,
 178		XFS_RTBLOCKLOG(postblock + 1 - preblock),
 179		XFS_BITTOBLOCK(mp, preblock), -1, rbpp, rsb);
 180	if (error) {
 181		return error;
 182	}
 183	/*
 184	 * If there are blocks not being allocated at the front of the
 185	 * old extent, add summary data for them to be free.
 186	 */
 187	if (preblock < start) {
 188		error = xfs_rtmodify_summary(mp, tp,
 189			XFS_RTBLOCKLOG(start - preblock),
 190			XFS_BITTOBLOCK(mp, preblock), 1, rbpp, rsb);
 191		if (error) {
 192			return error;
 193		}
 194	}
 195	/*
 196	 * If there are blocks not being allocated at the end of the
 197	 * old extent, add summary data for them to be free.
 198	 */
 199	if (postblock > end) {
 200		error = xfs_rtmodify_summary(mp, tp,
 201			XFS_RTBLOCKLOG(postblock - end),
 202			XFS_BITTOBLOCK(mp, end + 1), 1, rbpp, rsb);
 203		if (error) {
 204			return error;
 205		}
 206	}
 207	/*
 208	 * Modify the bitmap to mark this extent allocated.
 209	 */
 210	error = xfs_rtmodify_range(mp, tp, start, len, 0);
 211	return error;
 212}
 213
 214/*
 215 * Attempt to allocate an extent minlen<=len<=maxlen starting from
 216 * bitmap block bbno.  If we don't get maxlen then use prod to trim
 217 * the length, if given.  Returns error; returns starting block in *rtblock.
 218 * The lengths are all in rtextents.
 219 */
 220STATIC int				/* error */
 221xfs_rtallocate_extent_block(
 222	xfs_mount_t	*mp,		/* file system mount point */
 223	xfs_trans_t	*tp,		/* transaction pointer */
 224	xfs_rtblock_t	bbno,		/* bitmap block number */
 225	xfs_extlen_t	minlen,		/* minimum length to allocate */
 226	xfs_extlen_t	maxlen,		/* maximum length to allocate */
 227	xfs_extlen_t	*len,		/* out: actual length allocated */
 228	xfs_rtblock_t	*nextp,		/* out: next block to try */
 229	xfs_buf_t	**rbpp,		/* in/out: summary block buffer */
 230	xfs_fsblock_t	*rsb,		/* in/out: summary block number */
 231	xfs_extlen_t	prod,		/* extent product factor */
 232	xfs_rtblock_t	*rtblock)	/* out: start block allocated */
 233{
 234	xfs_rtblock_t	besti;		/* best rtblock found so far */
 235	xfs_rtblock_t	bestlen;	/* best length found so far */
 236	xfs_rtblock_t	end;		/* last rtblock in chunk */
 237	int		error;		/* error value */
 238	xfs_rtblock_t	i;		/* current rtblock trying */
 239	xfs_rtblock_t	next;		/* next rtblock to try */
 240	int		stat;		/* status from internal calls */
 241
 242	/*
 243	 * Loop over all the extents starting in this bitmap block,
 244	 * looking for one that's long enough.
 245	 */
 246	for (i = XFS_BLOCKTOBIT(mp, bbno), besti = -1, bestlen = 0,
 247		end = XFS_BLOCKTOBIT(mp, bbno + 1) - 1;
 248	     i <= end;
 249	     i++) {
 250		/*
 251		 * See if there's a free extent of maxlen starting at i.
 252		 * If it's not so then next will contain the first non-free.
 253		 */
 254		error = xfs_rtcheck_range(mp, tp, i, maxlen, 1, &next, &stat);
 255		if (error) {
 256			return error;
 257		}
 258		if (stat) {
 259			/*
 260			 * i for maxlen is all free, allocate and return that.
 261			 */
 262			error = xfs_rtallocate_range(mp, tp, i, maxlen, rbpp,
 263				rsb);
 264			if (error) {
 265				return error;
 266			}
 267			*len = maxlen;
 268			*rtblock = i;
 269			return 0;
 270		}
 271		/*
 272		 * In the case where we have a variable-sized allocation
 273		 * request, figure out how big this free piece is,
 274		 * and if it's big enough for the minimum, and the best
 275		 * so far, remember it.
 276		 */
 277		if (minlen < maxlen) {
 278			xfs_rtblock_t	thislen;	/* this extent size */
 279
 280			thislen = next - i;
 281			if (thislen >= minlen && thislen > bestlen) {
 282				besti = i;
 283				bestlen = thislen;
 284			}
 285		}
 286		/*
 287		 * If not done yet, find the start of the next free space.
 288		 */
 289		if (next < end) {
 290			error = xfs_rtfind_forw(mp, tp, next, end, &i);
 291			if (error) {
 292				return error;
 293			}
 294		} else
 295			break;
 296	}
 297	/*
 298	 * Searched the whole thing & didn't find a maxlen free extent.
 299	 */
 300	if (minlen < maxlen && besti != -1) {
 301		xfs_extlen_t	p;	/* amount to trim length by */
 302
 303		/*
 304		 * If size should be a multiple of prod, make that so.
 305		 */
 306		if (prod > 1) {
 307			div_u64_rem(bestlen, prod, &p);
 308			if (p)
 309				bestlen -= p;
 310		}
 311
 312		/*
 313		 * Allocate besti for bestlen & return that.
 314		 */
 315		error = xfs_rtallocate_range(mp, tp, besti, bestlen, rbpp, rsb);
 316		if (error) {
 317			return error;
 318		}
 319		*len = bestlen;
 320		*rtblock = besti;
 321		return 0;
 322	}
 323	/*
 324	 * Allocation failed.  Set *nextp to the next block to try.
 325	 */
 326	*nextp = next;
 327	*rtblock = NULLRTBLOCK;
 328	return 0;
 329}
 330
 331/*
 332 * Allocate an extent of length minlen<=len<=maxlen, starting at block
 333 * bno.  If we don't get maxlen then use prod to trim the length, if given.
 334 * Returns error; returns starting block in *rtblock.
 335 * The lengths are all in rtextents.
 336 */
 337STATIC int				/* error */
 338xfs_rtallocate_extent_exact(
 339	xfs_mount_t	*mp,		/* file system mount point */
 340	xfs_trans_t	*tp,		/* transaction pointer */
 341	xfs_rtblock_t	bno,		/* starting block number to allocate */
 342	xfs_extlen_t	minlen,		/* minimum length to allocate */
 343	xfs_extlen_t	maxlen,		/* maximum length to allocate */
 344	xfs_extlen_t	*len,		/* out: actual length allocated */
 345	xfs_buf_t	**rbpp,		/* in/out: summary block buffer */
 346	xfs_fsblock_t	*rsb,		/* in/out: summary block number */
 347	xfs_extlen_t	prod,		/* extent product factor */
 348	xfs_rtblock_t	*rtblock)	/* out: start block allocated */
 349{
 350	int		error;		/* error value */
 351	xfs_extlen_t	i;		/* extent length trimmed due to prod */
 352	int		isfree;		/* extent is free */
 353	xfs_rtblock_t	next;		/* next block to try (dummy) */
 354
 355	ASSERT(minlen % prod == 0 && maxlen % prod == 0);
 356	/*
 357	 * Check if the range in question (for maxlen) is free.
 358	 */
 359	error = xfs_rtcheck_range(mp, tp, bno, maxlen, 1, &next, &isfree);
 360	if (error) {
 361		return error;
 362	}
 363	if (isfree) {
 364		/*
 365		 * If it is, allocate it and return success.
 366		 */
 367		error = xfs_rtallocate_range(mp, tp, bno, maxlen, rbpp, rsb);
 368		if (error) {
 369			return error;
 370		}
 371		*len = maxlen;
 372		*rtblock = bno;
 373		return 0;
 374	}
 375	/*
 376	 * If not, allocate what there is, if it's at least minlen.
 377	 */
 378	maxlen = next - bno;
 379	if (maxlen < minlen) {
 380		/*
 381		 * Failed, return failure status.
 382		 */
 383		*rtblock = NULLRTBLOCK;
 384		return 0;
 385	}
 386	/*
 387	 * Trim off tail of extent, if prod is specified.
 388	 */
 389	if (prod > 1 && (i = maxlen % prod)) {
 390		maxlen -= i;
 391		if (maxlen < minlen) {
 392			/*
 393			 * Now we can't do it, return failure status.
 394			 */
 395			*rtblock = NULLRTBLOCK;
 396			return 0;
 397		}
 398	}
 399	/*
 400	 * Allocate what we can and return it.
 401	 */
 402	error = xfs_rtallocate_range(mp, tp, bno, maxlen, rbpp, rsb);
 403	if (error) {
 404		return error;
 405	}
 406	*len = maxlen;
 407	*rtblock = bno;
 408	return 0;
 409}
 410
 411/*
 412 * Allocate an extent of length minlen<=len<=maxlen, starting as near
 413 * to bno as possible.  If we don't get maxlen then use prod to trim
 414 * the length, if given.  The lengths are all in rtextents.
 415 */
 416STATIC int				/* error */
 417xfs_rtallocate_extent_near(
 418	xfs_mount_t	*mp,		/* file system mount point */
 419	xfs_trans_t	*tp,		/* transaction pointer */
 420	xfs_rtblock_t	bno,		/* starting block number to allocate */
 421	xfs_extlen_t	minlen,		/* minimum length to allocate */
 422	xfs_extlen_t	maxlen,		/* maximum length to allocate */
 423	xfs_extlen_t	*len,		/* out: actual length allocated */
 424	xfs_buf_t	**rbpp,		/* in/out: summary block buffer */
 425	xfs_fsblock_t	*rsb,		/* in/out: summary block number */
 426	xfs_extlen_t	prod,		/* extent product factor */
 427	xfs_rtblock_t	*rtblock)	/* out: start block allocated */
 428{
 429	int		any;		/* any useful extents from summary */
 430	xfs_rtblock_t	bbno;		/* bitmap block number */
 431	int		error;		/* error value */
 432	int		i;		/* bitmap block offset (loop control) */
 433	int		j;		/* secondary loop control */
 434	int		log2len;	/* log2 of minlen */
 435	xfs_rtblock_t	n;		/* next block to try */
 436	xfs_rtblock_t	r;		/* result block */
 437
 438	ASSERT(minlen % prod == 0 && maxlen % prod == 0);
 439	/*
 440	 * If the block number given is off the end, silently set it to
 441	 * the last block.
 442	 */
 443	if (bno >= mp->m_sb.sb_rextents)
 444		bno = mp->m_sb.sb_rextents - 1;
 445	/*
 446	 * Try the exact allocation first.
 447	 */
 448	error = xfs_rtallocate_extent_exact(mp, tp, bno, minlen, maxlen, len,
 449		rbpp, rsb, prod, &r);
 450	if (error) {
 451		return error;
 452	}
 453	/*
 454	 * If the exact allocation worked, return that.
 455	 */
 456	if (r != NULLRTBLOCK) {
 457		*rtblock = r;
 458		return 0;
 459	}
 460	bbno = XFS_BITTOBLOCK(mp, bno);
 461	i = 0;
 462	ASSERT(minlen != 0);
 463	log2len = xfs_highbit32(minlen);
 464	/*
 465	 * Loop over all bitmap blocks (bbno + i is current block).
 466	 */
 467	for (;;) {
 468		/*
 469		 * Get summary information of extents of all useful levels
 470		 * starting in this bitmap block.
 471		 */
 472		error = xfs_rtany_summary(mp, tp, log2len, mp->m_rsumlevels - 1,
 473			bbno + i, rbpp, rsb, &any);
 474		if (error) {
 475			return error;
 476		}
 477		/*
 478		 * If there are any useful extents starting here, try
 479		 * allocating one.
 480		 */
 481		if (any) {
 482			/*
 483			 * On the positive side of the starting location.
 484			 */
 485			if (i >= 0) {
 486				/*
 487				 * Try to allocate an extent starting in
 488				 * this block.
 489				 */
 490				error = xfs_rtallocate_extent_block(mp, tp,
 491					bbno + i, minlen, maxlen, len, &n, rbpp,
 492					rsb, prod, &r);
 493				if (error) {
 494					return error;
 495				}
 496				/*
 497				 * If it worked, return it.
 498				 */
 499				if (r != NULLRTBLOCK) {
 500					*rtblock = r;
 501					return 0;
 502				}
 503			}
 504			/*
 505			 * On the negative side of the starting location.
 506			 */
 507			else {		/* i < 0 */
 508				/*
 509				 * Loop backwards through the bitmap blocks from
 510				 * the starting point-1 up to where we are now.
 511				 * There should be an extent which ends in this
 512				 * bitmap block and is long enough.
 513				 */
 514				for (j = -1; j > i; j--) {
 515					/*
 516					 * Grab the summary information for
 517					 * this bitmap block.
 518					 */
 519					error = xfs_rtany_summary(mp, tp,
 520						log2len, mp->m_rsumlevels - 1,
 521						bbno + j, rbpp, rsb, &any);
 522					if (error) {
 523						return error;
 524					}
 525					/*
 526					 * If there's no extent given in the
 527					 * summary that means the extent we
 528					 * found must carry over from an
 529					 * earlier block.  If there is an
 530					 * extent given, we've already tried
 531					 * that allocation, don't do it again.
 532					 */
 533					if (any)
 534						continue;
 535					error = xfs_rtallocate_extent_block(mp,
 536						tp, bbno + j, minlen, maxlen,
 537						len, &n, rbpp, rsb, prod, &r);
 538					if (error) {
 539						return error;
 540					}
 541					/*
 542					 * If it works, return the extent.
 543					 */
 544					if (r != NULLRTBLOCK) {
 545						*rtblock = r;
 546						return 0;
 547					}
 548				}
 549				/*
 550				 * There weren't intervening bitmap blocks
 551				 * with a long enough extent, or the
 552				 * allocation didn't work for some reason
 553				 * (i.e. it's a little * too short).
 554				 * Try to allocate from the summary block
 555				 * that we found.
 556				 */
 557				error = xfs_rtallocate_extent_block(mp, tp,
 558					bbno + i, minlen, maxlen, len, &n, rbpp,
 559					rsb, prod, &r);
 560				if (error) {
 561					return error;
 562				}
 563				/*
 564				 * If it works, return the extent.
 565				 */
 566				if (r != NULLRTBLOCK) {
 567					*rtblock = r;
 568					return 0;
 569				}
 570			}
 571		}
 572		/*
 573		 * Loop control.  If we were on the positive side, and there's
 574		 * still more blocks on the negative side, go there.
 575		 */
 576		if (i > 0 && (int)bbno - i >= 0)
 577			i = -i;
 578		/*
 579		 * If positive, and no more negative, but there are more
 580		 * positive, go there.
 581		 */
 582		else if (i > 0 && (int)bbno + i < mp->m_sb.sb_rbmblocks - 1)
 583			i++;
 584		/*
 585		 * If negative or 0 (just started), and there are positive
 586		 * blocks to go, go there.  The 0 case moves to block 1.
 587		 */
 588		else if (i <= 0 && (int)bbno - i < mp->m_sb.sb_rbmblocks - 1)
 589			i = 1 - i;
 590		/*
 591		 * If negative or 0 and there are more negative blocks,
 592		 * go there.
 593		 */
 594		else if (i <= 0 && (int)bbno + i > 0)
 595			i--;
 596		/*
 597		 * Must be done.  Return failure.
 598		 */
 599		else
 600			break;
 601	}
 602	*rtblock = NULLRTBLOCK;
 603	return 0;
 604}
 605
 606/*
 607 * Allocate an extent of length minlen<=len<=maxlen, with no position
 608 * specified.  If we don't get maxlen then use prod to trim
 609 * the length, if given.  The lengths are all in rtextents.
 610 */
 611STATIC int				/* error */
 612xfs_rtallocate_extent_size(
 613	xfs_mount_t	*mp,		/* file system mount point */
 614	xfs_trans_t	*tp,		/* transaction pointer */
 615	xfs_extlen_t	minlen,		/* minimum length to allocate */
 616	xfs_extlen_t	maxlen,		/* maximum length to allocate */
 617	xfs_extlen_t	*len,		/* out: actual length allocated */
 618	xfs_buf_t	**rbpp,		/* in/out: summary block buffer */
 619	xfs_fsblock_t	*rsb,		/* in/out: summary block number */
 620	xfs_extlen_t	prod,		/* extent product factor */
 621	xfs_rtblock_t	*rtblock)	/* out: start block allocated */
 622{
 623	int		error;		/* error value */
 624	int		i;		/* bitmap block number */
 625	int		l;		/* level number (loop control) */
 626	xfs_rtblock_t	n;		/* next block to be tried */
 627	xfs_rtblock_t	r;		/* result block number */
 628	xfs_suminfo_t	sum;		/* summary information for extents */
 629
 630	ASSERT(minlen % prod == 0 && maxlen % prod == 0);
 631	ASSERT(maxlen != 0);
 632
 633	/*
 634	 * Loop over all the levels starting with maxlen.
 635	 * At each level, look at all the bitmap blocks, to see if there
 636	 * are extents starting there that are long enough (>= maxlen).
 637	 * Note, only on the initial level can the allocation fail if
 638	 * the summary says there's an extent.
 639	 */
 640	for (l = xfs_highbit32(maxlen); l < mp->m_rsumlevels; l++) {
 641		/*
 642		 * Loop over all the bitmap blocks.
 643		 */
 644		for (i = 0; i < mp->m_sb.sb_rbmblocks; i++) {
 645			/*
 646			 * Get the summary for this level/block.
 647			 */
 648			error = xfs_rtget_summary(mp, tp, l, i, rbpp, rsb,
 649				&sum);
 650			if (error) {
 651				return error;
 652			}
 653			/*
 654			 * Nothing there, on to the next block.
 655			 */
 656			if (!sum)
 657				continue;
 658			/*
 659			 * Try allocating the extent.
 660			 */
 661			error = xfs_rtallocate_extent_block(mp, tp, i, maxlen,
 662				maxlen, len, &n, rbpp, rsb, prod, &r);
 663			if (error) {
 664				return error;
 665			}
 666			/*
 667			 * If it worked, return that.
 668			 */
 669			if (r != NULLRTBLOCK) {
 670				*rtblock = r;
 671				return 0;
 672			}
 673			/*
 674			 * If the "next block to try" returned from the
 675			 * allocator is beyond the next bitmap block,
 676			 * skip to that bitmap block.
 677			 */
 678			if (XFS_BITTOBLOCK(mp, n) > i + 1)
 679				i = XFS_BITTOBLOCK(mp, n) - 1;
 680		}
 681	}
 682	/*
 683	 * Didn't find any maxlen blocks.  Try smaller ones, unless
 684	 * we're asking for a fixed size extent.
 685	 */
 686	if (minlen > --maxlen) {
 687		*rtblock = NULLRTBLOCK;
 688		return 0;
 689	}
 690	ASSERT(minlen != 0);
 691	ASSERT(maxlen != 0);
 692
 693	/*
 694	 * Loop over sizes, from maxlen down to minlen.
 695	 * This time, when we do the allocations, allow smaller ones
 696	 * to succeed.
 697	 */
 698	for (l = xfs_highbit32(maxlen); l >= xfs_highbit32(minlen); l--) {
 699		/*
 700		 * Loop over all the bitmap blocks, try an allocation
 701		 * starting in that block.
 702		 */
 703		for (i = 0; i < mp->m_sb.sb_rbmblocks; i++) {
 704			/*
 705			 * Get the summary information for this level/block.
 706			 */
 707			error =	xfs_rtget_summary(mp, tp, l, i, rbpp, rsb,
 708						  &sum);
 709			if (error) {
 710				return error;
 711			}
 712			/*
 713			 * If nothing there, go on to next.
 714			 */
 715			if (!sum)
 716				continue;
 717			/*
 718			 * Try the allocation.  Make sure the specified
 719			 * minlen/maxlen are in the possible range for
 720			 * this summary level.
 721			 */
 722			error = xfs_rtallocate_extent_block(mp, tp, i,
 723					XFS_RTMAX(minlen, 1 << l),
 724					XFS_RTMIN(maxlen, (1 << (l + 1)) - 1),
 725					len, &n, rbpp, rsb, prod, &r);
 726			if (error) {
 727				return error;
 728			}
 729			/*
 730			 * If it worked, return that extent.
 731			 */
 732			if (r != NULLRTBLOCK) {
 733				*rtblock = r;
 734				return 0;
 735			}
 736			/*
 737			 * If the "next block to try" returned from the
 738			 * allocator is beyond the next bitmap block,
 739			 * skip to that bitmap block.
 740			 */
 741			if (XFS_BITTOBLOCK(mp, n) > i + 1)
 742				i = XFS_BITTOBLOCK(mp, n) - 1;
 743		}
 744	}
 745	/*
 746	 * Got nothing, return failure.
 747	 */
 748	*rtblock = NULLRTBLOCK;
 749	return 0;
 750}
 751
 752/*
 753 * Allocate space to the bitmap or summary file, and zero it, for growfs.
 754 */
 755STATIC int
 756xfs_growfs_rt_alloc(
 757	struct xfs_mount	*mp,		/* file system mount point */
 758	xfs_extlen_t		oblocks,	/* old count of blocks */
 759	xfs_extlen_t		nblocks,	/* new count of blocks */
 760	struct xfs_inode	*ip)		/* inode (bitmap/summary) */
 761{
 762	xfs_fileoff_t		bno;		/* block number in file */
 763	struct xfs_buf		*bp;	/* temporary buffer for zeroing */
 764	xfs_daddr_t		d;		/* disk block address */
 765	int			error;		/* error return value */
 766	xfs_fsblock_t		fsbno;		/* filesystem block for bno */
 767	struct xfs_bmbt_irec	map;		/* block map output */
 768	int			nmap;		/* number of block maps */
 769	int			resblks;	/* space reservation */
 770	struct xfs_trans	*tp;
 771
 772	/*
 773	 * Allocate space to the file, as necessary.
 774	 */
 775	while (oblocks < nblocks) {
 776		resblks = XFS_GROWFSRT_SPACE_RES(mp, nblocks - oblocks);
 777		/*
 778		 * Reserve space & log for one extent added to the file.
 779		 */
 780		error = xfs_trans_alloc(mp, &M_RES(mp)->tr_growrtalloc, resblks,
 781				0, 0, &tp);
 782		if (error)
 783			return error;
 784		/*
 785		 * Lock the inode.
 786		 */
 787		xfs_ilock(ip, XFS_ILOCK_EXCL);
 788		xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
 789
 790		/*
 791		 * Allocate blocks to the bitmap file.
 792		 */
 793		nmap = 1;
 794		error = xfs_bmapi_write(tp, ip, oblocks, nblocks - oblocks,
 795					XFS_BMAPI_METADATA, 0, &map, &nmap);
 
 796		if (!error && nmap < 1)
 797			error = -ENOSPC;
 798		if (error)
 799			goto out_trans_cancel;
 800		/*
 801		 * Free any blocks freed up in the transaction, then commit.
 802		 */
 803		error = xfs_trans_commit(tp);
 804		if (error)
 805			return error;
 806		/*
 807		 * Now we need to clear the allocated blocks.
 808		 * Do this one block per transaction, to keep it simple.
 809		 */
 810		for (bno = map.br_startoff, fsbno = map.br_startblock;
 811		     bno < map.br_startoff + map.br_blockcount;
 812		     bno++, fsbno++) {
 813			/*
 814			 * Reserve log for one block zeroing.
 815			 */
 816			error = xfs_trans_alloc(mp, &M_RES(mp)->tr_growrtzero,
 817					0, 0, 0, &tp);
 818			if (error)
 819				return error;
 820			/*
 821			 * Lock the bitmap inode.
 822			 */
 823			xfs_ilock(ip, XFS_ILOCK_EXCL);
 824			xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
 825			/*
 826			 * Get a buffer for the block.
 827			 */
 828			d = XFS_FSB_TO_DADDR(mp, fsbno);
 829			error = xfs_trans_get_buf(tp, mp->m_ddev_targp, d,
 830					mp->m_bsize, 0, &bp);
 831			if (error)
 
 832				goto out_trans_cancel;
 
 833			memset(bp->b_addr, 0, mp->m_sb.sb_blocksize);
 834			xfs_trans_log_buf(tp, bp, 0, mp->m_sb.sb_blocksize - 1);
 835			/*
 836			 * Commit the transaction.
 837			 */
 838			error = xfs_trans_commit(tp);
 839			if (error)
 840				return error;
 841		}
 842		/*
 843		 * Go on to the next extent, if any.
 844		 */
 845		oblocks = map.br_startoff + map.br_blockcount;
 846	}
 847
 848	return 0;
 849
 850out_trans_cancel:
 851	xfs_trans_cancel(tp);
 852	return error;
 853}
 854
 855static void
 856xfs_alloc_rsum_cache(
 857	xfs_mount_t	*mp,		/* file system mount structure */
 858	xfs_extlen_t	rbmblocks)	/* number of rt bitmap blocks */
 859{
 860	/*
 861	 * The rsum cache is initialized to all zeroes, which is trivially a
 862	 * lower bound on the minimum level with any free extents. We can
 863	 * continue without the cache if it couldn't be allocated.
 864	 */
 865	mp->m_rsum_cache = kmem_zalloc_large(rbmblocks, 0);
 866	if (!mp->m_rsum_cache)
 867		xfs_warn(mp, "could not allocate realtime summary cache");
 868}
 869
 870/*
 871 * Visible (exported) functions.
 872 */
 873
 874/*
 875 * Grow the realtime area of the filesystem.
 876 */
 877int
 878xfs_growfs_rt(
 879	xfs_mount_t	*mp,		/* mount point for filesystem */
 880	xfs_growfs_rt_t	*in)		/* growfs rt input struct */
 881{
 882	xfs_rtblock_t	bmbno;		/* bitmap block number */
 883	xfs_buf_t	*bp;		/* temporary buffer */
 884	int		error;		/* error return value */
 885	xfs_mount_t	*nmp;		/* new (fake) mount structure */
 886	xfs_rfsblock_t	nrblocks;	/* new number of realtime blocks */
 887	xfs_extlen_t	nrbmblocks;	/* new number of rt bitmap blocks */
 888	xfs_rtblock_t	nrextents;	/* new number of realtime extents */
 889	uint8_t		nrextslog;	/* new log2 of sb_rextents */
 890	xfs_extlen_t	nrsumblocks;	/* new number of summary blocks */
 891	uint		nrsumlevels;	/* new rt summary levels */
 892	uint		nrsumsize;	/* new size of rt summary, bytes */
 893	xfs_sb_t	*nsbp;		/* new superblock */
 894	xfs_extlen_t	rbmblocks;	/* current number of rt bitmap blocks */
 895	xfs_extlen_t	rsumblocks;	/* current number of rt summary blks */
 896	xfs_sb_t	*sbp;		/* old superblock */
 897	xfs_fsblock_t	sumbno;		/* summary block number */
 898	uint8_t		*rsum_cache;	/* old summary cache */
 899
 900	sbp = &mp->m_sb;
 901	/*
 902	 * Initial error checking.
 903	 */
 904	if (!capable(CAP_SYS_ADMIN))
 905		return -EPERM;
 906	if (mp->m_rtdev_targp == NULL || mp->m_rbmip == NULL ||
 907	    (nrblocks = in->newblocks) <= sbp->sb_rblocks ||
 908	    (sbp->sb_rblocks && (in->extsize != sbp->sb_rextsize)))
 909		return -EINVAL;
 910	if ((error = xfs_sb_validate_fsb_count(sbp, nrblocks)))
 911		return error;
 912	/*
 913	 * Read in the last block of the device, make sure it exists.
 914	 */
 915	error = xfs_buf_read_uncached(mp->m_rtdev_targp,
 916				XFS_FSB_TO_BB(mp, nrblocks - 1),
 917				XFS_FSB_TO_BB(mp, 1), 0, &bp, NULL);
 918	if (error)
 919		return error;
 920	xfs_buf_relse(bp);
 921
 922	/*
 923	 * Calculate new parameters.  These are the final values to be reached.
 924	 */
 925	nrextents = nrblocks;
 926	do_div(nrextents, in->extsize);
 927	nrbmblocks = howmany_64(nrextents, NBBY * sbp->sb_blocksize);
 928	nrextslog = xfs_highbit32(nrextents);
 929	nrsumlevels = nrextslog + 1;
 930	nrsumsize = (uint)sizeof(xfs_suminfo_t) * nrsumlevels * nrbmblocks;
 931	nrsumblocks = XFS_B_TO_FSB(mp, nrsumsize);
 932	nrsumsize = XFS_FSB_TO_B(mp, nrsumblocks);
 933	/*
 934	 * New summary size can't be more than half the size of
 935	 * the log.  This prevents us from getting a log overflow,
 936	 * since we'll log basically the whole summary file at once.
 937	 */
 938	if (nrsumblocks > (mp->m_sb.sb_logblocks >> 1))
 939		return -EINVAL;
 940	/*
 941	 * Get the old block counts for bitmap and summary inodes.
 942	 * These can't change since other growfs callers are locked out.
 943	 */
 944	rbmblocks = XFS_B_TO_FSB(mp, mp->m_rbmip->i_d.di_size);
 945	rsumblocks = XFS_B_TO_FSB(mp, mp->m_rsumip->i_d.di_size);
 946	/*
 947	 * Allocate space to the bitmap and summary files, as necessary.
 948	 */
 949	error = xfs_growfs_rt_alloc(mp, rbmblocks, nrbmblocks, mp->m_rbmip);
 950	if (error)
 951		return error;
 952	error = xfs_growfs_rt_alloc(mp, rsumblocks, nrsumblocks, mp->m_rsumip);
 953	if (error)
 954		return error;
 955
 956	rsum_cache = mp->m_rsum_cache;
 957	if (nrbmblocks != sbp->sb_rbmblocks)
 958		xfs_alloc_rsum_cache(mp, nrbmblocks);
 959
 960	/*
 961	 * Allocate a new (fake) mount/sb.
 962	 */
 963	nmp = kmem_alloc(sizeof(*nmp), 0);
 964	/*
 965	 * Loop over the bitmap blocks.
 966	 * We will do everything one bitmap block at a time.
 967	 * Skip the current block if it is exactly full.
 968	 * This also deals with the case where there were no rtextents before.
 969	 */
 970	for (bmbno = sbp->sb_rbmblocks -
 971		     ((sbp->sb_rextents & ((1 << mp->m_blkbit_log) - 1)) != 0);
 972	     bmbno < nrbmblocks;
 973	     bmbno++) {
 974		xfs_trans_t	*tp;
 975
 976		*nmp = *mp;
 977		nsbp = &nmp->m_sb;
 978		/*
 979		 * Calculate new sb and mount fields for this round.
 980		 */
 981		nsbp->sb_rextsize = in->extsize;
 982		nsbp->sb_rbmblocks = bmbno + 1;
 983		nsbp->sb_rblocks =
 984			XFS_RTMIN(nrblocks,
 985				  nsbp->sb_rbmblocks * NBBY *
 986				  nsbp->sb_blocksize * nsbp->sb_rextsize);
 987		nsbp->sb_rextents = nsbp->sb_rblocks;
 988		do_div(nsbp->sb_rextents, nsbp->sb_rextsize);
 989		ASSERT(nsbp->sb_rextents != 0);
 990		nsbp->sb_rextslog = xfs_highbit32(nsbp->sb_rextents);
 991		nrsumlevels = nmp->m_rsumlevels = nsbp->sb_rextslog + 1;
 992		nrsumsize =
 993			(uint)sizeof(xfs_suminfo_t) * nrsumlevels *
 994			nsbp->sb_rbmblocks;
 995		nrsumblocks = XFS_B_TO_FSB(mp, nrsumsize);
 996		nmp->m_rsumsize = nrsumsize = XFS_FSB_TO_B(mp, nrsumblocks);
 997		/*
 998		 * Start a transaction, get the log reservation.
 999		 */
1000		error = xfs_trans_alloc(mp, &M_RES(mp)->tr_growrtfree, 0, 0, 0,
1001				&tp);
1002		if (error)
1003			break;
1004		/*
1005		 * Lock out other callers by grabbing the bitmap inode lock.
1006		 */
1007		xfs_ilock(mp->m_rbmip, XFS_ILOCK_EXCL);
1008		xfs_trans_ijoin(tp, mp->m_rbmip, XFS_ILOCK_EXCL);
1009		/*
1010		 * Update the bitmap inode's size.
1011		 */
1012		mp->m_rbmip->i_d.di_size =
1013			nsbp->sb_rbmblocks * nsbp->sb_blocksize;
1014		xfs_trans_log_inode(tp, mp->m_rbmip, XFS_ILOG_CORE);
1015		/*
1016		 * Get the summary inode into the transaction.
1017		 */
1018		xfs_ilock(mp->m_rsumip, XFS_ILOCK_EXCL);
1019		xfs_trans_ijoin(tp, mp->m_rsumip, XFS_ILOCK_EXCL);
1020		/*
1021		 * Update the summary inode's size.
1022		 */
1023		mp->m_rsumip->i_d.di_size = nmp->m_rsumsize;
1024		xfs_trans_log_inode(tp, mp->m_rsumip, XFS_ILOG_CORE);
1025		/*
1026		 * Copy summary data from old to new sizes.
1027		 * Do this when the real size (not block-aligned) changes.
1028		 */
1029		if (sbp->sb_rbmblocks != nsbp->sb_rbmblocks ||
1030		    mp->m_rsumlevels != nmp->m_rsumlevels) {
1031			error = xfs_rtcopy_summary(mp, nmp, tp);
1032			if (error)
1033				goto error_cancel;
1034		}
1035		/*
1036		 * Update superblock fields.
1037		 */
1038		if (nsbp->sb_rextsize != sbp->sb_rextsize)
1039			xfs_trans_mod_sb(tp, XFS_TRANS_SB_REXTSIZE,
1040				nsbp->sb_rextsize - sbp->sb_rextsize);
1041		if (nsbp->sb_rbmblocks != sbp->sb_rbmblocks)
1042			xfs_trans_mod_sb(tp, XFS_TRANS_SB_RBMBLOCKS,
1043				nsbp->sb_rbmblocks - sbp->sb_rbmblocks);
1044		if (nsbp->sb_rblocks != sbp->sb_rblocks)
1045			xfs_trans_mod_sb(tp, XFS_TRANS_SB_RBLOCKS,
1046				nsbp->sb_rblocks - sbp->sb_rblocks);
1047		if (nsbp->sb_rextents != sbp->sb_rextents)
1048			xfs_trans_mod_sb(tp, XFS_TRANS_SB_REXTENTS,
1049				nsbp->sb_rextents - sbp->sb_rextents);
1050		if (nsbp->sb_rextslog != sbp->sb_rextslog)
1051			xfs_trans_mod_sb(tp, XFS_TRANS_SB_REXTSLOG,
1052				nsbp->sb_rextslog - sbp->sb_rextslog);
1053		/*
1054		 * Free new extent.
1055		 */
1056		bp = NULL;
1057		error = xfs_rtfree_range(nmp, tp, sbp->sb_rextents,
1058			nsbp->sb_rextents - sbp->sb_rextents, &bp, &sumbno);
1059		if (error) {
1060error_cancel:
1061			xfs_trans_cancel(tp);
1062			break;
1063		}
1064		/*
1065		 * Mark more blocks free in the superblock.
1066		 */
1067		xfs_trans_mod_sb(tp, XFS_TRANS_SB_FREXTENTS,
1068			nsbp->sb_rextents - sbp->sb_rextents);
1069		/*
1070		 * Update mp values into the real mp structure.
1071		 */
1072		mp->m_rsumlevels = nrsumlevels;
1073		mp->m_rsumsize = nrsumsize;
1074
1075		error = xfs_trans_commit(tp);
1076		if (error)
1077			break;
1078	}
1079
1080	/*
1081	 * Free the fake mp structure.
1082	 */
1083	kmem_free(nmp);
1084
1085	/*
1086	 * If we had to allocate a new rsum_cache, we either need to free the
1087	 * old one (if we succeeded) or free the new one and restore the old one
1088	 * (if there was an error).
1089	 */
1090	if (rsum_cache != mp->m_rsum_cache) {
1091		if (error) {
1092			kmem_free(mp->m_rsum_cache);
1093			mp->m_rsum_cache = rsum_cache;
1094		} else {
1095			kmem_free(rsum_cache);
1096		}
1097	}
1098
1099	return error;
1100}
1101
1102/*
1103 * Allocate an extent in the realtime subvolume, with the usual allocation
1104 * parameters.  The length units are all in realtime extents, as is the
1105 * result block number.
1106 */
1107int					/* error */
1108xfs_rtallocate_extent(
1109	xfs_trans_t	*tp,		/* transaction pointer */
1110	xfs_rtblock_t	bno,		/* starting block number to allocate */
1111	xfs_extlen_t	minlen,		/* minimum length to allocate */
1112	xfs_extlen_t	maxlen,		/* maximum length to allocate */
1113	xfs_extlen_t	*len,		/* out: actual length allocated */
1114	int		wasdel,		/* was a delayed allocation extent */
1115	xfs_extlen_t	prod,		/* extent product factor */
1116	xfs_rtblock_t	*rtblock)	/* out: start block allocated */
1117{
1118	xfs_mount_t	*mp = tp->t_mountp;
1119	int		error;		/* error value */
1120	xfs_rtblock_t	r;		/* result allocated block */
1121	xfs_fsblock_t	sb;		/* summary file block number */
1122	xfs_buf_t	*sumbp;		/* summary file block buffer */
1123
1124	ASSERT(xfs_isilocked(mp->m_rbmip, XFS_ILOCK_EXCL));
1125	ASSERT(minlen > 0 && minlen <= maxlen);
1126
1127	/*
1128	 * If prod is set then figure out what to do to minlen and maxlen.
1129	 */
1130	if (prod > 1) {
1131		xfs_extlen_t	i;
1132
1133		if ((i = maxlen % prod))
1134			maxlen -= i;
1135		if ((i = minlen % prod))
1136			minlen += prod - i;
1137		if (maxlen < minlen) {
1138			*rtblock = NULLRTBLOCK;
1139			return 0;
1140		}
1141	}
1142
1143retry:
1144	sumbp = NULL;
1145	if (bno == 0) {
1146		error = xfs_rtallocate_extent_size(mp, tp, minlen, maxlen, len,
1147				&sumbp,	&sb, prod, &r);
1148	} else {
1149		error = xfs_rtallocate_extent_near(mp, tp, bno, minlen, maxlen,
1150				len, &sumbp, &sb, prod, &r);
1151	}
1152
1153	if (error)
1154		return error;
1155
1156	/*
1157	 * If it worked, update the superblock.
1158	 */
1159	if (r != NULLRTBLOCK) {
1160		long	slen = (long)*len;
1161
1162		ASSERT(*len >= minlen && *len <= maxlen);
1163		if (wasdel)
1164			xfs_trans_mod_sb(tp, XFS_TRANS_SB_RES_FREXTENTS, -slen);
1165		else
1166			xfs_trans_mod_sb(tp, XFS_TRANS_SB_FREXTENTS, -slen);
1167	} else if (prod > 1) {
1168		prod = 1;
1169		goto retry;
1170	}
1171
1172	*rtblock = r;
1173	return 0;
1174}
1175
1176/*
1177 * Initialize realtime fields in the mount structure.
1178 */
1179int				/* error */
1180xfs_rtmount_init(
1181	struct xfs_mount	*mp)	/* file system mount structure */
1182{
1183	struct xfs_buf		*bp;	/* buffer for last block of subvolume */
1184	struct xfs_sb		*sbp;	/* filesystem superblock copy in mount */
1185	xfs_daddr_t		d;	/* address of last block of subvolume */
1186	int			error;
1187
1188	sbp = &mp->m_sb;
1189	if (sbp->sb_rblocks == 0)
1190		return 0;
1191	if (mp->m_rtdev_targp == NULL) {
1192		xfs_warn(mp,
1193	"Filesystem has a realtime volume, use rtdev=device option");
1194		return -ENODEV;
1195	}
1196	mp->m_rsumlevels = sbp->sb_rextslog + 1;
1197	mp->m_rsumsize =
1198		(uint)sizeof(xfs_suminfo_t) * mp->m_rsumlevels *
1199		sbp->sb_rbmblocks;
1200	mp->m_rsumsize = roundup(mp->m_rsumsize, sbp->sb_blocksize);
1201	mp->m_rbmip = mp->m_rsumip = NULL;
1202	/*
1203	 * Check that the realtime section is an ok size.
1204	 */
1205	d = (xfs_daddr_t)XFS_FSB_TO_BB(mp, mp->m_sb.sb_rblocks);
1206	if (XFS_BB_TO_FSB(mp, d) != mp->m_sb.sb_rblocks) {
1207		xfs_warn(mp, "realtime mount -- %llu != %llu",
1208			(unsigned long long) XFS_BB_TO_FSB(mp, d),
1209			(unsigned long long) mp->m_sb.sb_rblocks);
1210		return -EFBIG;
1211	}
1212	error = xfs_buf_read_uncached(mp->m_rtdev_targp,
1213					d - XFS_FSB_TO_BB(mp, 1),
1214					XFS_FSB_TO_BB(mp, 1), 0, &bp, NULL);
1215	if (error) {
1216		xfs_warn(mp, "realtime device size check failed");
1217		return error;
1218	}
1219	xfs_buf_relse(bp);
1220	return 0;
1221}
1222
1223/*
1224 * Get the bitmap and summary inodes and the summary cache into the mount
1225 * structure at mount time.
1226 */
1227int					/* error */
1228xfs_rtmount_inodes(
1229	xfs_mount_t	*mp)		/* file system mount structure */
1230{
1231	int		error;		/* error return value */
1232	xfs_sb_t	*sbp;
1233
1234	sbp = &mp->m_sb;
1235	error = xfs_iget(mp, NULL, sbp->sb_rbmino, 0, 0, &mp->m_rbmip);
1236	if (error)
1237		return error;
1238	ASSERT(mp->m_rbmip != NULL);
1239
1240	error = xfs_iget(mp, NULL, sbp->sb_rsumino, 0, 0, &mp->m_rsumip);
1241	if (error) {
1242		xfs_irele(mp->m_rbmip);
1243		return error;
1244	}
1245	ASSERT(mp->m_rsumip != NULL);
1246	xfs_alloc_rsum_cache(mp, sbp->sb_rbmblocks);
1247	return 0;
1248}
1249
1250void
1251xfs_rtunmount_inodes(
1252	struct xfs_mount	*mp)
1253{
1254	kmem_free(mp->m_rsum_cache);
1255	if (mp->m_rbmip)
1256		xfs_irele(mp->m_rbmip);
1257	if (mp->m_rsumip)
1258		xfs_irele(mp->m_rsumip);
1259}
1260
1261/*
1262 * Pick an extent for allocation at the start of a new realtime file.
1263 * Use the sequence number stored in the atime field of the bitmap inode.
1264 * Translate this to a fraction of the rtextents, and return the product
1265 * of rtextents and the fraction.
1266 * The fraction sequence is 0, 1/2, 1/4, 3/4, 1/8, ..., 7/8, 1/16, ...
1267 */
1268int					/* error */
1269xfs_rtpick_extent(
1270	xfs_mount_t	*mp,		/* file system mount point */
1271	xfs_trans_t	*tp,		/* transaction pointer */
1272	xfs_extlen_t	len,		/* allocation length (rtextents) */
1273	xfs_rtblock_t	*pick)		/* result rt extent */
1274{
1275	xfs_rtblock_t	b;		/* result block */
1276	int		log2;		/* log of sequence number */
1277	uint64_t	resid;		/* residual after log removed */
1278	uint64_t	seq;		/* sequence number of file creation */
1279	uint64_t	*seqp;		/* pointer to seqno in inode */
1280
1281	ASSERT(xfs_isilocked(mp->m_rbmip, XFS_ILOCK_EXCL));
1282
1283	seqp = (uint64_t *)&VFS_I(mp->m_rbmip)->i_atime;
1284	if (!(mp->m_rbmip->i_d.di_flags & XFS_DIFLAG_NEWRTBM)) {
1285		mp->m_rbmip->i_d.di_flags |= XFS_DIFLAG_NEWRTBM;
1286		*seqp = 0;
1287	}
1288	seq = *seqp;
1289	if ((log2 = xfs_highbit64(seq)) == -1)
1290		b = 0;
1291	else {
1292		resid = seq - (1ULL << log2);
1293		b = (mp->m_sb.sb_rextents * ((resid << 1) + 1ULL)) >>
1294		    (log2 + 1);
1295		if (b >= mp->m_sb.sb_rextents)
1296			div64_u64_rem(b, mp->m_sb.sb_rextents, &b);
1297		if (b + len > mp->m_sb.sb_rextents)
1298			b = mp->m_sb.sb_rextents - len;
1299	}
1300	*seqp = seq + 1;
1301	xfs_trans_log_inode(tp, mp->m_rbmip, XFS_ILOG_CORE);
1302	*pick = b;
1303	return 0;
1304}