1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Copyright (c) 2000-2006 Silicon Graphics, Inc.
   4 * Copyright (c) 2012 Red Hat, Inc.
   5 * All Rights Reserved.
   6 */
   7#include "xfs.h"
   8#include "xfs_fs.h"
   9#include "xfs_shared.h"
  10#include "xfs_format.h"
  11#include "xfs_log_format.h"
  12#include "xfs_trans_resv.h"
  13#include "xfs_bit.h"
  14#include "xfs_mount.h"
  15#include "xfs_defer.h"
  16#include "xfs_inode.h"
  17#include "xfs_btree.h"
  18#include "xfs_trans.h"
  19#include "xfs_alloc.h"
  20#include "xfs_bmap.h"
  21#include "xfs_bmap_util.h"
  22#include "xfs_bmap_btree.h"
  23#include "xfs_rtalloc.h"
  24#include "xfs_error.h"
  25#include "xfs_quota.h"
  26#include "xfs_trans_space.h"
  27#include "xfs_trace.h"
  28#include "xfs_icache.h"
  29#include "xfs_iomap.h"
  30#include "xfs_reflink.h"
  31#include "xfs_rtbitmap.h"
  32
  33/* Kernel only BMAP related definitions and functions */
  34
  35/*
  36 * Convert the given file system block to a disk block.  We have to treat it
  37 * differently based on whether the file is a real time file or not, because the
  38 * bmap code does.
  39 */
  40xfs_daddr_t
  41xfs_fsb_to_db(struct xfs_inode *ip, xfs_fsblock_t fsb)
  42{
  43	if (XFS_IS_REALTIME_INODE(ip))
  44		return XFS_FSB_TO_BB(ip->i_mount, fsb);
  45	return XFS_FSB_TO_DADDR(ip->i_mount, fsb);
  46}
  47
  48/*
  49 * Routine to zero an extent on disk allocated to the specific inode.
  50 *
  51 * The VFS functions take a linearised filesystem block offset, so we have to
  52 * convert the sparse xfs fsb to the right format first.
  53 * VFS types are real funky, too.
  54 */
  55int
  56xfs_zero_extent(
  57	struct xfs_inode	*ip,
  58	xfs_fsblock_t		start_fsb,
  59	xfs_off_t		count_fsb)
  60{
  61	struct xfs_mount	*mp = ip->i_mount;
  62	struct xfs_buftarg	*target = xfs_inode_buftarg(ip);
  63	xfs_daddr_t		sector = xfs_fsb_to_db(ip, start_fsb);
  64	sector_t		block = XFS_BB_TO_FSBT(mp, sector);
  65
  66	return blkdev_issue_zeroout(target->bt_bdev,
  67		block << (mp->m_super->s_blocksize_bits - 9),
  68		count_fsb << (mp->m_super->s_blocksize_bits - 9),
  69		GFP_NOFS, 0);
  70}
  71
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  72/*
  73 * Extent tree block counting routines.
  74 */
  75
  76/*
  77 * Count leaf blocks given a range of extent records.  Delayed allocation
  78 * extents are not counted towards the totals.
  79 */
  80xfs_extnum_t
  81xfs_bmap_count_leaves(
  82	struct xfs_ifork	*ifp,
  83	xfs_filblks_t		*count)
  84{
  85	struct xfs_iext_cursor	icur;
  86	struct xfs_bmbt_irec	got;
  87	xfs_extnum_t		numrecs = 0;
  88
  89	for_each_xfs_iext(ifp, &icur, &got) {
  90		if (!isnullstartblock(got.br_startblock)) {
  91			*count += got.br_blockcount;
  92			numrecs++;
  93		}
  94	}
  95
  96	return numrecs;
  97}
  98
  99/*
 100 * Count fsblocks of the given fork.  Delayed allocation extents are
 101 * not counted towards the totals.
 102 */
 103int
 104xfs_bmap_count_blocks(
 105	struct xfs_trans	*tp,
 106	struct xfs_inode	*ip,
 107	int			whichfork,
 108	xfs_extnum_t		*nextents,
 109	xfs_filblks_t		*count)
 110{
 111	struct xfs_mount	*mp = ip->i_mount;
 112	struct xfs_ifork	*ifp = xfs_ifork_ptr(ip, whichfork);
 113	struct xfs_btree_cur	*cur;
 114	xfs_extlen_t		btblocks = 0;
 115	int			error;
 116
 117	*nextents = 0;
 118	*count = 0;
 119
 120	if (!ifp)
 121		return 0;
 122
 123	switch (ifp->if_format) {
 124	case XFS_DINODE_FMT_BTREE:
 125		error = xfs_iread_extents(tp, ip, whichfork);
 126		if (error)
 127			return error;
 
 
 128
 129		cur = xfs_bmbt_init_cursor(mp, tp, ip, whichfork);
 130		error = xfs_btree_count_blocks(cur, &btblocks);
 131		xfs_btree_del_cursor(cur, error);
 132		if (error)
 133			return error;
 134
 135		/*
 136		 * xfs_btree_count_blocks includes the root block contained in
 137		 * the inode fork in @btblocks, so subtract one because we're
 138		 * only interested in allocated disk blocks.
 139		 */
 140		*count += btblocks - 1;
 141
 142		fallthrough;
 143	case XFS_DINODE_FMT_EXTENTS:
 144		*nextents = xfs_bmap_count_leaves(ifp, count);
 145		break;
 146	}
 147
 148	return 0;
 149}
 150
 151static int
 152xfs_getbmap_report_one(
 153	struct xfs_inode	*ip,
 154	struct getbmapx		*bmv,
 155	struct kgetbmap		*out,
 156	int64_t			bmv_end,
 157	struct xfs_bmbt_irec	*got)
 158{
 159	struct kgetbmap		*p = out + bmv->bmv_entries;
 160	bool			shared = false;
 161	int			error;
 162
 163	error = xfs_reflink_trim_around_shared(ip, got, &shared);
 164	if (error)
 165		return error;
 166
 167	if (isnullstartblock(got->br_startblock) ||
 168	    got->br_startblock == DELAYSTARTBLOCK) {
 169		/*
 170		 * Take the flush completion as being a point-in-time snapshot
 171		 * where there are no delalloc extents, and if any new ones
 172		 * have been created racily, just skip them as being 'after'
 173		 * the flush and so don't get reported.
 
 
 174		 */
 175		if (!(bmv->bmv_iflags & BMV_IF_DELALLOC))
 176			return 0;
 177
 178		p->bmv_oflags |= BMV_OF_DELALLOC;
 179		p->bmv_block = -2;
 180	} else {
 181		p->bmv_block = xfs_fsb_to_db(ip, got->br_startblock);
 182	}
 183
 184	if (got->br_state == XFS_EXT_UNWRITTEN &&
 185	    (bmv->bmv_iflags & BMV_IF_PREALLOC))
 186		p->bmv_oflags |= BMV_OF_PREALLOC;
 187
 188	if (shared)
 189		p->bmv_oflags |= BMV_OF_SHARED;
 190
 191	p->bmv_offset = XFS_FSB_TO_BB(ip->i_mount, got->br_startoff);
 192	p->bmv_length = XFS_FSB_TO_BB(ip->i_mount, got->br_blockcount);
 193
 194	bmv->bmv_offset = p->bmv_offset + p->bmv_length;
 195	bmv->bmv_length = max(0LL, bmv_end - bmv->bmv_offset);
 196	bmv->bmv_entries++;
 197	return 0;
 198}
 199
 200static void
 201xfs_getbmap_report_hole(
 202	struct xfs_inode	*ip,
 203	struct getbmapx		*bmv,
 204	struct kgetbmap		*out,
 205	int64_t			bmv_end,
 206	xfs_fileoff_t		bno,
 207	xfs_fileoff_t		end)
 208{
 209	struct kgetbmap		*p = out + bmv->bmv_entries;
 210
 211	if (bmv->bmv_iflags & BMV_IF_NO_HOLES)
 212		return;
 213
 214	p->bmv_block = -1;
 215	p->bmv_offset = XFS_FSB_TO_BB(ip->i_mount, bno);
 216	p->bmv_length = XFS_FSB_TO_BB(ip->i_mount, end - bno);
 217
 218	bmv->bmv_offset = p->bmv_offset + p->bmv_length;
 219	bmv->bmv_length = max(0LL, bmv_end - bmv->bmv_offset);
 220	bmv->bmv_entries++;
 221}
 222
 223static inline bool
 224xfs_getbmap_full(
 225	struct getbmapx		*bmv)
 226{
 227	return bmv->bmv_length == 0 || bmv->bmv_entries >= bmv->bmv_count - 1;
 228}
 229
 230static bool
 231xfs_getbmap_next_rec(
 232	struct xfs_bmbt_irec	*rec,
 233	xfs_fileoff_t		total_end)
 234{
 235	xfs_fileoff_t		end = rec->br_startoff + rec->br_blockcount;
 236
 237	if (end == total_end)
 238		return false;
 239
 240	rec->br_startoff += rec->br_blockcount;
 241	if (!isnullstartblock(rec->br_startblock) &&
 242	    rec->br_startblock != DELAYSTARTBLOCK)
 243		rec->br_startblock += rec->br_blockcount;
 244	rec->br_blockcount = total_end - end;
 245	return true;
 246}
 247
 248/*
 249 * Get inode's extents as described in bmv, and format for output.
 250 * Calls formatter to fill the user's buffer until all extents
 251 * are mapped, until the passed-in bmv->bmv_count slots have
 252 * been filled, or until the formatter short-circuits the loop,
 253 * if it is tracking filled-in extents on its own.
 254 */
 255int						/* error code */
 256xfs_getbmap(
 257	struct xfs_inode	*ip,
 258	struct getbmapx		*bmv,		/* user bmap structure */
 259	struct kgetbmap		*out)
 260{
 261	struct xfs_mount	*mp = ip->i_mount;
 262	int			iflags = bmv->bmv_iflags;
 263	int			whichfork, lock, error = 0;
 264	int64_t			bmv_end, max_len;
 265	xfs_fileoff_t		bno, first_bno;
 266	struct xfs_ifork	*ifp;
 267	struct xfs_bmbt_irec	got, rec;
 268	xfs_filblks_t		len;
 269	struct xfs_iext_cursor	icur;
 270
 271	if (bmv->bmv_iflags & ~BMV_IF_VALID)
 272		return -EINVAL;
 273#ifndef DEBUG
 274	/* Only allow CoW fork queries if we're debugging. */
 275	if (iflags & BMV_IF_COWFORK)
 276		return -EINVAL;
 277#endif
 278	if ((iflags & BMV_IF_ATTRFORK) && (iflags & BMV_IF_COWFORK))
 279		return -EINVAL;
 280
 281	if (bmv->bmv_length < -1)
 282		return -EINVAL;
 283	bmv->bmv_entries = 0;
 284	if (bmv->bmv_length == 0)
 285		return 0;
 286
 287	if (iflags & BMV_IF_ATTRFORK)
 288		whichfork = XFS_ATTR_FORK;
 289	else if (iflags & BMV_IF_COWFORK)
 290		whichfork = XFS_COW_FORK;
 291	else
 292		whichfork = XFS_DATA_FORK;
 
 293
 294	xfs_ilock(ip, XFS_IOLOCK_SHARED);
 295	switch (whichfork) {
 296	case XFS_ATTR_FORK:
 297		lock = xfs_ilock_attr_map_shared(ip);
 298		if (!xfs_inode_has_attr_fork(ip))
 299			goto out_unlock_ilock;
 300
 301		max_len = 1LL << 32;
 
 302		break;
 303	case XFS_COW_FORK:
 304		lock = XFS_ILOCK_SHARED;
 305		xfs_ilock(ip, lock);
 306
 307		/* No CoW fork? Just return */
 308		if (!xfs_ifork_ptr(ip, whichfork))
 309			goto out_unlock_ilock;
 310
 311		if (xfs_get_cowextsz_hint(ip))
 312			max_len = mp->m_super->s_maxbytes;
 313		else
 314			max_len = XFS_ISIZE(ip);
 
 
 
 315		break;
 316	case XFS_DATA_FORK:
 317		if (!(iflags & BMV_IF_DELALLOC) &&
 318		    (ip->i_delayed_blks || XFS_ISIZE(ip) > ip->i_disk_size)) {
 319			error = filemap_write_and_wait(VFS_I(ip)->i_mapping);
 320			if (error)
 321				goto out_unlock_iolock;
 322
 323			/*
 324			 * Even after flushing the inode, there can still be
 325			 * delalloc blocks on the inode beyond EOF due to
 326			 * speculative preallocation.  These are not removed
 327			 * until the release function is called or the inode
 328			 * is inactivated.  Hence we cannot assert here that
 329			 * ip->i_delayed_blks == 0.
 330			 */
 331		}
 332
 333		if (xfs_get_extsz_hint(ip) ||
 334		    (ip->i_diflags &
 335		     (XFS_DIFLAG_PREALLOC | XFS_DIFLAG_APPEND)))
 336			max_len = mp->m_super->s_maxbytes;
 337		else
 338			max_len = XFS_ISIZE(ip);
 339
 340		lock = xfs_ilock_data_map_shared(ip);
 341		break;
 342	}
 343
 344	ifp = xfs_ifork_ptr(ip, whichfork);
 345
 346	switch (ifp->if_format) {
 347	case XFS_DINODE_FMT_EXTENTS:
 348	case XFS_DINODE_FMT_BTREE:
 349		break;
 350	case XFS_DINODE_FMT_LOCAL:
 351		/* Local format inode forks report no extents. */
 352		goto out_unlock_ilock;
 353	default:
 354		error = -EINVAL;
 355		goto out_unlock_ilock;
 356	}
 357
 358	if (bmv->bmv_length == -1) {
 359		max_len = XFS_FSB_TO_BB(mp, XFS_B_TO_FSB(mp, max_len));
 360		bmv->bmv_length = max(0LL, max_len - bmv->bmv_offset);
 361	}
 362
 363	bmv_end = bmv->bmv_offset + bmv->bmv_length;
 364
 365	first_bno = bno = XFS_BB_TO_FSBT(mp, bmv->bmv_offset);
 366	len = XFS_BB_TO_FSB(mp, bmv->bmv_length);
 367
 368	error = xfs_iread_extents(NULL, ip, whichfork);
 369	if (error)
 370		goto out_unlock_ilock;
 
 
 371
 372	if (!xfs_iext_lookup_extent(ip, ifp, bno, &icur, &got)) {
 373		/*
 374		 * Report a whole-file hole if the delalloc flag is set to
 375		 * stay compatible with the old implementation.
 376		 */
 377		if (iflags & BMV_IF_DELALLOC)
 378			xfs_getbmap_report_hole(ip, bmv, out, bmv_end, bno,
 379					XFS_B_TO_FSB(mp, XFS_ISIZE(ip)));
 380		goto out_unlock_ilock;
 381	}
 382
 383	while (!xfs_getbmap_full(bmv)) {
 384		xfs_trim_extent(&got, first_bno, len);
 385
 386		/*
 387		 * Report an entry for a hole if this extent doesn't directly
 388		 * follow the previous one.
 389		 */
 390		if (got.br_startoff > bno) {
 391			xfs_getbmap_report_hole(ip, bmv, out, bmv_end, bno,
 392					got.br_startoff);
 393			if (xfs_getbmap_full(bmv))
 394				break;
 395		}
 396
 397		/*
 398		 * In order to report shared extents accurately, we report each
 399		 * distinct shared / unshared part of a single bmbt record with
 400		 * an individual getbmapx record.
 401		 */
 402		bno = got.br_startoff + got.br_blockcount;
 403		rec = got;
 404		do {
 405			error = xfs_getbmap_report_one(ip, bmv, out, bmv_end,
 406					&rec);
 407			if (error || xfs_getbmap_full(bmv))
 408				goto out_unlock_ilock;
 409		} while (xfs_getbmap_next_rec(&rec, bno));
 410
 411		if (!xfs_iext_next_extent(ifp, &icur, &got)) {
 412			xfs_fileoff_t	end = XFS_B_TO_FSB(mp, XFS_ISIZE(ip));
 413
 414			if (bmv->bmv_entries > 0)
 415				out[bmv->bmv_entries - 1].bmv_oflags |=
 416								BMV_OF_LAST;
 417
 418			if (whichfork != XFS_ATTR_FORK && bno < end &&
 419			    !xfs_getbmap_full(bmv)) {
 420				xfs_getbmap_report_hole(ip, bmv, out, bmv_end,
 421						bno, end);
 422			}
 423			break;
 424		}
 425
 426		if (bno >= first_bno + len)
 427			break;
 428	}
 429
 430out_unlock_ilock:
 431	xfs_iunlock(ip, lock);
 432out_unlock_iolock:
 433	xfs_iunlock(ip, XFS_IOLOCK_SHARED);
 434	return error;
 435}
 436
 437/*
 438 * Dead simple method of punching delalyed allocation blocks from a range in
 439 * the inode.  This will always punch out both the start and end blocks, even
 440 * if the ranges only partially overlap them, so it is up to the caller to
 441 * ensure that partial blocks are not passed in.
 442 */
 443int
 444xfs_bmap_punch_delalloc_range(
 445	struct xfs_inode	*ip,
 446	xfs_off_t		start_byte,
 447	xfs_off_t		end_byte)
 448{
 449	struct xfs_mount	*mp = ip->i_mount;
 450	struct xfs_ifork	*ifp = &ip->i_df;
 451	xfs_fileoff_t		start_fsb = XFS_B_TO_FSBT(mp, start_byte);
 452	xfs_fileoff_t		end_fsb = XFS_B_TO_FSB(mp, end_byte);
 453	struct xfs_bmbt_irec	got, del;
 454	struct xfs_iext_cursor	icur;
 455	int			error = 0;
 456
 457	ASSERT(!xfs_need_iread_extents(ifp));
 458
 459	xfs_ilock(ip, XFS_ILOCK_EXCL);
 460	if (!xfs_iext_lookup_extent_before(ip, ifp, &end_fsb, &icur, &got))
 461		goto out_unlock;
 462
 463	while (got.br_startoff + got.br_blockcount > start_fsb) {
 464		del = got;
 465		xfs_trim_extent(&del, start_fsb, end_fsb - start_fsb);
 466
 467		/*
 468		 * A delete can push the cursor forward. Step back to the
 469		 * previous extent on non-delalloc or extents outside the
 470		 * target range.
 471		 */
 472		if (!del.br_blockcount ||
 473		    !isnullstartblock(del.br_startblock)) {
 474			if (!xfs_iext_prev_extent(ifp, &icur, &got))
 475				break;
 476			continue;
 477		}
 478
 479		error = xfs_bmap_del_extent_delay(ip, XFS_DATA_FORK, &icur,
 480						  &got, &del);
 481		if (error || !xfs_iext_get_extent(ifp, &icur, &got))
 482			break;
 483	}
 484
 485out_unlock:
 486	xfs_iunlock(ip, XFS_ILOCK_EXCL);
 487	return error;
 488}
 489
 490/*
 491 * Test whether it is appropriate to check an inode for and free post EOF
 492 * blocks. The 'force' parameter determines whether we should also consider
 493 * regular files that are marked preallocated or append-only.
 494 */
 495bool
 496xfs_can_free_eofblocks(
 497	struct xfs_inode	*ip,
 498	bool			force)
 499{
 500	struct xfs_bmbt_irec	imap;
 501	struct xfs_mount	*mp = ip->i_mount;
 502	xfs_fileoff_t		end_fsb;
 503	xfs_fileoff_t		last_fsb;
 504	int			nimaps = 1;
 505	int			error;
 506
 507	/*
 508	 * Caller must either hold the exclusive io lock; or be inactivating
 509	 * the inode, which guarantees there are no other users of the inode.
 510	 */
 511	ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL) ||
 512	       (VFS_I(ip)->i_state & I_FREEING));
 513
 514	/* prealloc/delalloc exists only on regular files */
 515	if (!S_ISREG(VFS_I(ip)->i_mode))
 516		return false;
 517
 518	/*
 519	 * Zero sized files with no cached pages and delalloc blocks will not
 520	 * have speculative prealloc/delalloc blocks to remove.
 521	 */
 522	if (VFS_I(ip)->i_size == 0 &&
 523	    VFS_I(ip)->i_mapping->nrpages == 0 &&
 524	    ip->i_delayed_blks == 0)
 525		return false;
 526
 527	/* If we haven't read in the extent list, then don't do it now. */
 528	if (xfs_need_iread_extents(&ip->i_df))
 529		return false;
 530
 531	/*
 532	 * Do not free real preallocated or append-only files unless the file
 533	 * has delalloc blocks and we are forced to remove them.
 534	 */
 535	if (ip->i_diflags & (XFS_DIFLAG_PREALLOC | XFS_DIFLAG_APPEND))
 536		if (!force || ip->i_delayed_blks == 0)
 537			return false;
 538
 539	/*
 540	 * Do not try to free post-EOF blocks if EOF is beyond the end of the
 541	 * range supported by the page cache, because the truncation will loop
 542	 * forever.
 543	 */
 544	end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)XFS_ISIZE(ip));
 545	if (XFS_IS_REALTIME_INODE(ip) && mp->m_sb.sb_rextsize > 1)
 546		end_fsb = xfs_rtb_roundup_rtx(mp, end_fsb);
 547	last_fsb = XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes);
 548	if (last_fsb <= end_fsb)
 549		return false;
 550
 551	/*
 552	 * Look up the mapping for the first block past EOF.  If we can't find
 553	 * it, there's nothing to free.
 554	 */
 555	xfs_ilock(ip, XFS_ILOCK_SHARED);
 556	error = xfs_bmapi_read(ip, end_fsb, last_fsb - end_fsb, &imap, &nimaps,
 557			0);
 558	xfs_iunlock(ip, XFS_ILOCK_SHARED);
 559	if (error || nimaps == 0)
 560		return false;
 561
 562	/*
 563	 * If there's a real mapping there or there are delayed allocation
 564	 * reservations, then we have post-EOF blocks to try to free.
 565	 */
 566	return imap.br_startblock != HOLESTARTBLOCK || ip->i_delayed_blks;
 567}
 568
 569/*
 570 * This is called to free any blocks beyond eof. The caller must hold
 571 * IOLOCK_EXCL unless we are in the inode reclaim path and have the only
 572 * reference to the inode.
 573 */
 574int
 575xfs_free_eofblocks(
 576	struct xfs_inode	*ip)
 577{
 578	struct xfs_trans	*tp;
 579	struct xfs_mount	*mp = ip->i_mount;
 580	int			error;
 
 
 
 
 
 
 581
 582	/* Attach the dquots to the inode up front. */
 583	error = xfs_qm_dqattach(ip);
 584	if (error)
 585		return error;
 586
 587	/* Wait on dio to ensure i_size has settled. */
 588	inode_dio_wait(VFS_I(ip));
 589
 590	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate, 0, 0, 0, &tp);
 591	if (error) {
 592		ASSERT(xfs_is_shutdown(mp));
 593		return error;
 594	}
 595
 596	xfs_ilock(ip, XFS_ILOCK_EXCL);
 597	xfs_trans_ijoin(tp, ip, 0);
 
 
 598
 599	/*
 600	 * Do not update the on-disk file size.  If we update the on-disk file
 601	 * size and then the system crashes before the contents of the file are
 602	 * flushed to disk then the files may be full of holes (ie NULL files
 603	 * bug).
 604	 */
 605	error = xfs_itruncate_extents_flags(&tp, ip, XFS_DATA_FORK,
 606				XFS_ISIZE(ip), XFS_BMAPI_NODISCARD);
 607	if (error)
 608		goto err_cancel;
 
 
 
 
 
 609
 610	error = xfs_trans_commit(tp);
 611	if (error)
 612		goto out_unlock;
 613
 614	xfs_inode_clear_eofblocks_tag(ip);
 615	goto out_unlock;
 
 
 
 
 616
 617err_cancel:
 618	/*
 619	 * If we get an error at this point we simply don't
 620	 * bother truncating the file.
 621	 */
 622	xfs_trans_cancel(tp);
 623out_unlock:
 624	xfs_iunlock(ip, XFS_ILOCK_EXCL);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 625	return error;
 626}
 627
 628int
 629xfs_alloc_file_space(
 630	struct xfs_inode	*ip,
 631	xfs_off_t		offset,
 632	xfs_off_t		len)
 
 633{
 634	xfs_mount_t		*mp = ip->i_mount;
 635	xfs_off_t		count;
 
 636	xfs_filblks_t		allocatesize_fsb;
 637	xfs_extlen_t		extsz, temp;
 638	xfs_fileoff_t		startoffset_fsb;
 639	xfs_fileoff_t		endoffset_fsb;
 
 
 640	int			rt;
 641	xfs_trans_t		*tp;
 642	xfs_bmbt_irec_t		imaps[1], *imapp;
 
 643	int			error;
 644
 645	trace_xfs_alloc_file_space(ip);
 646
 647	if (xfs_is_shutdown(mp))
 648		return -EIO;
 649
 650	error = xfs_qm_dqattach(ip);
 651	if (error)
 652		return error;
 653
 654	if (len <= 0)
 655		return -EINVAL;
 656
 657	rt = XFS_IS_REALTIME_INODE(ip);
 658	extsz = xfs_get_extsz_hint(ip);
 659
 660	count = len;
 661	imapp = &imaps[0];
 
 662	startoffset_fsb	= XFS_B_TO_FSBT(mp, offset);
 663	endoffset_fsb = XFS_B_TO_FSB(mp, offset + count);
 664	allocatesize_fsb = endoffset_fsb - startoffset_fsb;
 665
 666	/*
 667	 * Allocate file space until done or until there is an error
 668	 */
 669	while (allocatesize_fsb && !error) {
 670		xfs_fileoff_t	s, e;
 671		unsigned int	dblocks, rblocks, resblks;
 672		int		nimaps = 1;
 673
 674		/*
 675		 * Determine space reservations for data/realtime.
 676		 */
 677		if (unlikely(extsz)) {
 678			s = startoffset_fsb;
 679			do_div(s, extsz);
 680			s *= extsz;
 681			e = startoffset_fsb + allocatesize_fsb;
 682			div_u64_rem(startoffset_fsb, extsz, &temp);
 683			if (temp)
 684				e += temp;
 685			div_u64_rem(e, extsz, &temp);
 686			if (temp)
 687				e += extsz - temp;
 688		} else {
 689			s = 0;
 690			e = allocatesize_fsb;
 691		}
 692
 693		/*
 694		 * The transaction reservation is limited to a 32-bit block
 695		 * count, hence we need to limit the number of blocks we are
 696		 * trying to reserve to avoid an overflow. We can't allocate
 697		 * more than @nimaps extents, and an extent is limited on disk
 698		 * to XFS_BMBT_MAX_EXTLEN (21 bits), so use that to enforce the
 699		 * limit.
 700		 */
 701		resblks = min_t(xfs_fileoff_t, (e - s),
 702				(XFS_MAX_BMBT_EXTLEN * nimaps));
 703		if (unlikely(rt)) {
 704			dblocks = XFS_DIOSTRAT_SPACE_RES(mp, 0);
 705			rblocks = resblks;
 
 
 706		} else {
 707			dblocks = XFS_DIOSTRAT_SPACE_RES(mp, resblks);
 708			rblocks = 0;
 
 709		}
 710
 711		error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write,
 712				dblocks, rblocks, false, &tp);
 713		if (error)
 714			break;
 
 715
 716		error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK,
 717				XFS_IEXT_ADD_NOSPLIT_CNT);
 718		if (error == -EFBIG)
 719			error = xfs_iext_count_upgrade(tp, ip,
 720					XFS_IEXT_ADD_NOSPLIT_CNT);
 
 
 
 
 
 
 
 
 721		if (error)
 722			goto error;
 
 
 723
 724		error = xfs_bmapi_write(tp, ip, startoffset_fsb,
 725				allocatesize_fsb, XFS_BMAPI_PREALLOC, 0, imapp,
 726				&nimaps);
 727		if (error)
 728			goto error;
 729
 730		ip->i_diflags |= XFS_DIFLAG_PREALLOC;
 731		xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
 732
 
 
 
 733		error = xfs_trans_commit(tp);
 734		xfs_iunlock(ip, XFS_ILOCK_EXCL);
 735		if (error)
 736			break;
 737
 738		/*
 739		 * If the allocator cannot find a single free extent large
 740		 * enough to cover the start block of the requested range,
 741		 * xfs_bmapi_write will return 0 but leave *nimaps set to 0.
 742		 *
 743		 * In that case we simply need to keep looping with the same
 744		 * startoffset_fsb so that one of the following allocations
 745		 * will eventually reach the requested range.
 746		 */
 747		if (nimaps) {
 748			startoffset_fsb += imapp->br_blockcount;
 749			allocatesize_fsb -= imapp->br_blockcount;
 750		}
 
 
 
 751	}
 752
 753	return error;
 754
 755error:
 
 
 
 756	xfs_trans_cancel(tp);
 757	xfs_iunlock(ip, XFS_ILOCK_EXCL);
 758	return error;
 759}
 760
 761static int
 762xfs_unmap_extent(
 763	struct xfs_inode	*ip,
 764	xfs_fileoff_t		startoffset_fsb,
 765	xfs_filblks_t		len_fsb,
 766	int			*done)
 767{
 768	struct xfs_mount	*mp = ip->i_mount;
 769	struct xfs_trans	*tp;
 770	uint			resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0);
 771	int			error;
 772
 773	error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write, resblks, 0,
 774			false, &tp);
 775	if (error)
 776		return error;
 
 777
 778	error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK,
 779			XFS_IEXT_PUNCH_HOLE_CNT);
 780	if (error == -EFBIG)
 781		error = xfs_iext_count_upgrade(tp, ip, XFS_IEXT_PUNCH_HOLE_CNT);
 782	if (error)
 783		goto out_trans_cancel;
 784
 
 
 785	error = xfs_bunmapi(tp, ip, startoffset_fsb, len_fsb, 0, 2, done);
 786	if (error)
 787		goto out_trans_cancel;
 788
 789	error = xfs_trans_commit(tp);
 790out_unlock:
 791	xfs_iunlock(ip, XFS_ILOCK_EXCL);
 792	return error;
 793
 794out_trans_cancel:
 795	xfs_trans_cancel(tp);
 796	goto out_unlock;
 797}
 798
 799/* Caller must first wait for the completion of any pending DIOs if required. */
 800int
 801xfs_flush_unmap_range(
 802	struct xfs_inode	*ip,
 803	xfs_off_t		offset,
 804	xfs_off_t		len)
 805{
 806	struct xfs_mount	*mp = ip->i_mount;
 807	struct inode		*inode = VFS_I(ip);
 808	xfs_off_t		rounding, start, end;
 809	int			error;
 810
 811	rounding = max_t(xfs_off_t, mp->m_sb.sb_blocksize, PAGE_SIZE);
 812	start = round_down(offset, rounding);
 813	end = round_up(offset + len, rounding) - 1;
 814
 815	error = filemap_write_and_wait_range(inode->i_mapping, start, end);
 816	if (error)
 817		return error;
 818	truncate_pagecache_range(inode, start, end);
 819	return 0;
 820}
 821
 822int
 823xfs_free_file_space(
 824	struct xfs_inode	*ip,
 825	xfs_off_t		offset,
 826	xfs_off_t		len)
 827{
 828	struct xfs_mount	*mp = ip->i_mount;
 829	xfs_fileoff_t		startoffset_fsb;
 830	xfs_fileoff_t		endoffset_fsb;
 831	int			done = 0, error;
 832
 833	trace_xfs_free_file_space(ip);
 834
 835	error = xfs_qm_dqattach(ip);
 836	if (error)
 837		return error;
 838
 839	if (len <= 0)	/* if nothing being freed */
 840		return 0;
 841
 842	startoffset_fsb = XFS_B_TO_FSB(mp, offset);
 843	endoffset_fsb = XFS_B_TO_FSBT(mp, offset + len);
 844
 845	/* We can only free complete realtime extents. */
 846	if (XFS_IS_REALTIME_INODE(ip) && mp->m_sb.sb_rextsize > 1) {
 847		startoffset_fsb = xfs_rtb_roundup_rtx(mp, startoffset_fsb);
 848		endoffset_fsb = xfs_rtb_rounddown_rtx(mp, endoffset_fsb);
 849	}
 850
 851	/*
 852	 * Need to zero the stuff we're not freeing, on disk.
 853	 */
 854	if (endoffset_fsb > startoffset_fsb) {
 855		while (!done) {
 856			error = xfs_unmap_extent(ip, startoffset_fsb,
 857					endoffset_fsb - startoffset_fsb, &done);
 858			if (error)
 859				return error;
 860		}
 861	}
 862
 863	/*
 864	 * Now that we've unmap all full blocks we'll have to zero out any
 865	 * partial block at the beginning and/or end.  xfs_zero_range is smart
 866	 * enough to skip any holes, including those we just created, but we
 867	 * must take care not to zero beyond EOF and enlarge i_size.
 868	 */
 869	if (offset >= XFS_ISIZE(ip))
 870		return 0;
 871	if (offset + len > XFS_ISIZE(ip))
 872		len = XFS_ISIZE(ip) - offset;
 873	error = xfs_zero_range(ip, offset, len, NULL);
 
 874	if (error)
 875		return error;
 876
 877	/*
 878	 * If we zeroed right up to EOF and EOF straddles a page boundary we
 879	 * must make sure that the post-EOF area is also zeroed because the
 880	 * page could be mmap'd and xfs_zero_range doesn't do that for us.
 881	 * Writeback of the eof page will do this, albeit clumsily.
 882	 */
 883	if (offset + len >= XFS_ISIZE(ip) && offset_in_page(offset + len) > 0) {
 884		error = filemap_write_and_wait_range(VFS_I(ip)->i_mapping,
 885				round_down(offset + len, PAGE_SIZE), LLONG_MAX);
 886	}
 887
 888	return error;
 889}
 890
 891static int
 892xfs_prepare_shift(
 893	struct xfs_inode	*ip,
 894	loff_t			offset)
 895{
 896	struct xfs_mount	*mp = ip->i_mount;
 897	int			error;
 898
 899	/*
 900	 * Trim eofblocks to avoid shifting uninitialized post-eof preallocation
 901	 * into the accessible region of the file.
 902	 */
 903	if (xfs_can_free_eofblocks(ip, true)) {
 904		error = xfs_free_eofblocks(ip);
 905		if (error)
 906			return error;
 907	}
 908
 909	/*
 910	 * Shift operations must stabilize the start block offset boundary along
 911	 * with the full range of the operation. If we don't, a COW writeback
 912	 * completion could race with an insert, front merge with the start
 913	 * extent (after split) during the shift and corrupt the file. Start
 914	 * with the block just prior to the start to stabilize the boundary.
 915	 */
 916	offset = round_down(offset, mp->m_sb.sb_blocksize);
 917	if (offset)
 918		offset -= mp->m_sb.sb_blocksize;
 919
 920	/*
 921	 * Writeback and invalidate cache for the remainder of the file as we're
 922	 * about to shift down every extent from offset to EOF.
 923	 */
 924	error = xfs_flush_unmap_range(ip, offset, XFS_ISIZE(ip));
 925	if (error)
 926		return error;
 927
 928	/*
 929	 * Clean out anything hanging around in the cow fork now that
 930	 * we've flushed all the dirty data out to disk to avoid having
 931	 * CoW extents at the wrong offsets.
 932	 */
 933	if (xfs_inode_has_cow_data(ip)) {
 934		error = xfs_reflink_cancel_cow_range(ip, offset, NULLFILEOFF,
 935				true);
 936		if (error)
 937			return error;
 938	}
 939
 940	return 0;
 941}
 942
 943/*
 944 * xfs_collapse_file_space()
 945 *	This routine frees disk space and shift extent for the given file.
 946 *	The first thing we do is to free data blocks in the specified range
 947 *	by calling xfs_free_file_space(). It would also sync dirty data
 948 *	and invalidate page cache over the region on which collapse range
 949 *	is working. And Shift extent records to the left to cover a hole.
 950 * RETURNS:
 951 *	0 on success
 952 *	errno on error
 953 *
 954 */
 955int
 956xfs_collapse_file_space(
 957	struct xfs_inode	*ip,
 958	xfs_off_t		offset,
 959	xfs_off_t		len)
 960{
 961	struct xfs_mount	*mp = ip->i_mount;
 962	struct xfs_trans	*tp;
 963	int			error;
 964	xfs_fileoff_t		next_fsb = XFS_B_TO_FSB(mp, offset + len);
 965	xfs_fileoff_t		shift_fsb = XFS_B_TO_FSB(mp, len);
 966	bool			done = false;
 967
 968	ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL));
 969	ASSERT(xfs_isilocked(ip, XFS_MMAPLOCK_EXCL));
 970
 971	trace_xfs_collapse_file_space(ip);
 972
 973	error = xfs_free_file_space(ip, offset, len);
 974	if (error)
 975		return error;
 976
 977	error = xfs_prepare_shift(ip, offset);
 978	if (error)
 979		return error;
 980
 981	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, 0, 0, 0, &tp);
 982	if (error)
 983		return error;
 984
 985	xfs_ilock(ip, XFS_ILOCK_EXCL);
 986	xfs_trans_ijoin(tp, ip, 0);
 987
 988	while (!done) {
 989		error = xfs_bmap_collapse_extents(tp, ip, &next_fsb, shift_fsb,
 990				&done);
 991		if (error)
 992			goto out_trans_cancel;
 993		if (done)
 994			break;
 995
 996		/* finish any deferred frees and roll the transaction */
 997		error = xfs_defer_finish(&tp);
 998		if (error)
 999			goto out_trans_cancel;
1000	}
1001
1002	error = xfs_trans_commit(tp);
1003	xfs_iunlock(ip, XFS_ILOCK_EXCL);
1004	return error;
1005
1006out_trans_cancel:
1007	xfs_trans_cancel(tp);
1008	xfs_iunlock(ip, XFS_ILOCK_EXCL);
1009	return error;
1010}
1011
1012/*
1013 * xfs_insert_file_space()
1014 *	This routine create hole space by shifting extents for the given file.
1015 *	The first thing we do is to sync dirty data and invalidate page cache
1016 *	over the region on which insert range is working. And split an extent
1017 *	to two extents at given offset by calling xfs_bmap_split_extent.
1018 *	And shift all extent records which are laying between [offset,
1019 *	last allocated extent] to the right to reserve hole range.
1020 * RETURNS:
1021 *	0 on success
1022 *	errno on error
1023 */
1024int
1025xfs_insert_file_space(
1026	struct xfs_inode	*ip,
1027	loff_t			offset,
1028	loff_t			len)
1029{
1030	struct xfs_mount	*mp = ip->i_mount;
1031	struct xfs_trans	*tp;
1032	int			error;
1033	xfs_fileoff_t		stop_fsb = XFS_B_TO_FSB(mp, offset);
1034	xfs_fileoff_t		next_fsb = NULLFSBLOCK;
1035	xfs_fileoff_t		shift_fsb = XFS_B_TO_FSB(mp, len);
1036	bool			done = false;
1037
1038	ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL));
1039	ASSERT(xfs_isilocked(ip, XFS_MMAPLOCK_EXCL));
1040
1041	trace_xfs_insert_file_space(ip);
1042
1043	error = xfs_bmap_can_insert_extents(ip, stop_fsb, shift_fsb);
1044	if (error)
1045		return error;
1046
1047	error = xfs_prepare_shift(ip, offset);
1048	if (error)
1049		return error;
1050
1051	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write,
1052			XFS_DIOSTRAT_SPACE_RES(mp, 0), 0, 0, &tp);
1053	if (error)
1054		return error;
1055
1056	xfs_ilock(ip, XFS_ILOCK_EXCL);
1057	xfs_trans_ijoin(tp, ip, 0);
1058
1059	error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK,
1060			XFS_IEXT_PUNCH_HOLE_CNT);
1061	if (error == -EFBIG)
1062		error = xfs_iext_count_upgrade(tp, ip, XFS_IEXT_PUNCH_HOLE_CNT);
1063	if (error)
1064		goto out_trans_cancel;
1065
1066	/*
1067	 * The extent shifting code works on extent granularity. So, if stop_fsb
1068	 * is not the starting block of extent, we need to split the extent at
1069	 * stop_fsb.
1070	 */
1071	error = xfs_bmap_split_extent(tp, ip, stop_fsb);
1072	if (error)
1073		goto out_trans_cancel;
1074
1075	do {
1076		error = xfs_defer_finish(&tp);
1077		if (error)
1078			goto out_trans_cancel;
1079
1080		error = xfs_bmap_insert_extents(tp, ip, &next_fsb, shift_fsb,
1081				&done, stop_fsb);
1082		if (error)
1083			goto out_trans_cancel;
1084	} while (!done);
1085
1086	error = xfs_trans_commit(tp);
1087	xfs_iunlock(ip, XFS_ILOCK_EXCL);
1088	return error;
1089
1090out_trans_cancel:
1091	xfs_trans_cancel(tp);
1092	xfs_iunlock(ip, XFS_ILOCK_EXCL);
1093	return error;
1094}
1095
1096/*
1097 * We need to check that the format of the data fork in the temporary inode is
1098 * valid for the target inode before doing the swap. This is not a problem with
1099 * attr1 because of the fixed fork offset, but attr2 has a dynamically sized
1100 * data fork depending on the space the attribute fork is taking so we can get
1101 * invalid formats on the target inode.
1102 *
1103 * E.g. target has space for 7 extents in extent format, temp inode only has
1104 * space for 6.  If we defragment down to 7 extents, then the tmp format is a
1105 * btree, but when swapped it needs to be in extent format. Hence we can't just
1106 * blindly swap data forks on attr2 filesystems.
1107 *
1108 * Note that we check the swap in both directions so that we don't end up with
1109 * a corrupt temporary inode, either.
1110 *
1111 * Note that fixing the way xfs_fsr sets up the attribute fork in the source
1112 * inode will prevent this situation from occurring, so all we do here is
1113 * reject and log the attempt. basically we are putting the responsibility on
1114 * userspace to get this right.
1115 */
1116static int
1117xfs_swap_extents_check_format(
1118	struct xfs_inode	*ip,	/* target inode */
1119	struct xfs_inode	*tip)	/* tmp inode */
1120{
1121	struct xfs_ifork	*ifp = &ip->i_df;
1122	struct xfs_ifork	*tifp = &tip->i_df;
1123
1124	/* User/group/project quota ids must match if quotas are enforced. */
1125	if (XFS_IS_QUOTA_ON(ip->i_mount) &&
1126	    (!uid_eq(VFS_I(ip)->i_uid, VFS_I(tip)->i_uid) ||
1127	     !gid_eq(VFS_I(ip)->i_gid, VFS_I(tip)->i_gid) ||
1128	     ip->i_projid != tip->i_projid))
1129		return -EINVAL;
1130
1131	/* Should never get a local format */
1132	if (ifp->if_format == XFS_DINODE_FMT_LOCAL ||
1133	    tifp->if_format == XFS_DINODE_FMT_LOCAL)
1134		return -EINVAL;
1135
1136	/*
1137	 * if the target inode has less extents that then temporary inode then
1138	 * why did userspace call us?
1139	 */
1140	if (ifp->if_nextents < tifp->if_nextents)
1141		return -EINVAL;
1142
1143	/*
1144	 * If we have to use the (expensive) rmap swap method, we can
1145	 * handle any number of extents and any format.
1146	 */
1147	if (xfs_has_rmapbt(ip->i_mount))
1148		return 0;
1149
1150	/*
1151	 * if the target inode is in extent form and the temp inode is in btree
1152	 * form then we will end up with the target inode in the wrong format
1153	 * as we already know there are less extents in the temp inode.
1154	 */
1155	if (ifp->if_format == XFS_DINODE_FMT_EXTENTS &&
1156	    tifp->if_format == XFS_DINODE_FMT_BTREE)
1157		return -EINVAL;
1158
1159	/* Check temp in extent form to max in target */
1160	if (tifp->if_format == XFS_DINODE_FMT_EXTENTS &&
1161	    tifp->if_nextents > XFS_IFORK_MAXEXT(ip, XFS_DATA_FORK))
1162		return -EINVAL;
1163
1164	/* Check target in extent form to max in temp */
1165	if (ifp->if_format == XFS_DINODE_FMT_EXTENTS &&
1166	    ifp->if_nextents > XFS_IFORK_MAXEXT(tip, XFS_DATA_FORK))
1167		return -EINVAL;
1168
1169	/*
1170	 * If we are in a btree format, check that the temp root block will fit
1171	 * in the target and that it has enough extents to be in btree format
1172	 * in the target.
1173	 *
1174	 * Note that we have to be careful to allow btree->extent conversions
1175	 * (a common defrag case) which will occur when the temp inode is in
1176	 * extent format...
1177	 */
1178	if (tifp->if_format == XFS_DINODE_FMT_BTREE) {
1179		if (xfs_inode_has_attr_fork(ip) &&
1180		    XFS_BMAP_BMDR_SPACE(tifp->if_broot) > xfs_inode_fork_boff(ip))
1181			return -EINVAL;
1182		if (tifp->if_nextents <= XFS_IFORK_MAXEXT(ip, XFS_DATA_FORK))
1183			return -EINVAL;
1184	}
1185
1186	/* Reciprocal target->temp btree format checks */
1187	if (ifp->if_format == XFS_DINODE_FMT_BTREE) {
1188		if (xfs_inode_has_attr_fork(tip) &&
1189		    XFS_BMAP_BMDR_SPACE(ip->i_df.if_broot) > xfs_inode_fork_boff(tip))
1190			return -EINVAL;
1191		if (ifp->if_nextents <= XFS_IFORK_MAXEXT(tip, XFS_DATA_FORK))
1192			return -EINVAL;
1193	}
1194
1195	return 0;
1196}
1197
1198static int
1199xfs_swap_extent_flush(
1200	struct xfs_inode	*ip)
1201{
1202	int	error;
1203
1204	error = filemap_write_and_wait(VFS_I(ip)->i_mapping);
1205	if (error)
1206		return error;
1207	truncate_pagecache_range(VFS_I(ip), 0, -1);
1208
1209	/* Verify O_DIRECT for ftmp */
1210	if (VFS_I(ip)->i_mapping->nrpages)
1211		return -EINVAL;
1212	return 0;
1213}
1214
1215/*
1216 * Move extents from one file to another, when rmap is enabled.
1217 */
1218STATIC int
1219xfs_swap_extent_rmap(
1220	struct xfs_trans		**tpp,
1221	struct xfs_inode		*ip,
1222	struct xfs_inode		*tip)
1223{
1224	struct xfs_trans		*tp = *tpp;
1225	struct xfs_bmbt_irec		irec;
1226	struct xfs_bmbt_irec		uirec;
1227	struct xfs_bmbt_irec		tirec;
1228	xfs_fileoff_t			offset_fsb;
1229	xfs_fileoff_t			end_fsb;
1230	xfs_filblks_t			count_fsb;
1231	int				error;
1232	xfs_filblks_t			ilen;
1233	xfs_filblks_t			rlen;
1234	int				nimaps;
1235	uint64_t			tip_flags2;
1236
1237	/*
1238	 * If the source file has shared blocks, we must flag the donor
1239	 * file as having shared blocks so that we get the shared-block
1240	 * rmap functions when we go to fix up the rmaps.  The flags
1241	 * will be switch for reals later.
1242	 */
1243	tip_flags2 = tip->i_diflags2;
1244	if (ip->i_diflags2 & XFS_DIFLAG2_REFLINK)
1245		tip->i_diflags2 |= XFS_DIFLAG2_REFLINK;
1246
1247	offset_fsb = 0;
1248	end_fsb = XFS_B_TO_FSB(ip->i_mount, i_size_read(VFS_I(ip)));
1249	count_fsb = (xfs_filblks_t)(end_fsb - offset_fsb);
1250
1251	while (count_fsb) {
1252		/* Read extent from the donor file */
1253		nimaps = 1;
1254		error = xfs_bmapi_read(tip, offset_fsb, count_fsb, &tirec,
1255				&nimaps, 0);
1256		if (error)
1257			goto out;
1258		ASSERT(nimaps == 1);
1259		ASSERT(tirec.br_startblock != DELAYSTARTBLOCK);
1260
1261		trace_xfs_swap_extent_rmap_remap(tip, &tirec);
1262		ilen = tirec.br_blockcount;
1263
1264		/* Unmap the old blocks in the source file. */
1265		while (tirec.br_blockcount) {
1266			ASSERT(tp->t_highest_agno == NULLAGNUMBER);
1267			trace_xfs_swap_extent_rmap_remap_piece(tip, &tirec);
1268
1269			/* Read extent from the source file */
1270			nimaps = 1;
1271			error = xfs_bmapi_read(ip, tirec.br_startoff,
1272					tirec.br_blockcount, &irec,
1273					&nimaps, 0);
1274			if (error)
1275				goto out;
1276			ASSERT(nimaps == 1);
1277			ASSERT(tirec.br_startoff == irec.br_startoff);
1278			trace_xfs_swap_extent_rmap_remap_piece(ip, &irec);
1279
1280			/* Trim the extent. */
1281			uirec = tirec;
1282			uirec.br_blockcount = rlen = min_t(xfs_filblks_t,
1283					tirec.br_blockcount,
1284					irec.br_blockcount);
1285			trace_xfs_swap_extent_rmap_remap_piece(tip, &uirec);
1286
1287			if (xfs_bmap_is_real_extent(&uirec)) {
1288				error = xfs_iext_count_may_overflow(ip,
1289						XFS_DATA_FORK,
1290						XFS_IEXT_SWAP_RMAP_CNT);
1291				if (error == -EFBIG)
1292					error = xfs_iext_count_upgrade(tp, ip,
1293							XFS_IEXT_SWAP_RMAP_CNT);
1294				if (error)
1295					goto out;
1296			}
1297
1298			if (xfs_bmap_is_real_extent(&irec)) {
1299				error = xfs_iext_count_may_overflow(tip,
1300						XFS_DATA_FORK,
1301						XFS_IEXT_SWAP_RMAP_CNT);
1302				if (error == -EFBIG)
1303					error = xfs_iext_count_upgrade(tp, ip,
1304							XFS_IEXT_SWAP_RMAP_CNT);
1305				if (error)
1306					goto out;
1307			}
1308
1309			/* Remove the mapping from the donor file. */
1310			xfs_bmap_unmap_extent(tp, tip, &uirec);
1311
1312			/* Remove the mapping from the source file. */
1313			xfs_bmap_unmap_extent(tp, ip, &irec);
1314
1315			/* Map the donor file's blocks into the source file. */
1316			xfs_bmap_map_extent(tp, ip, &uirec);
1317
1318			/* Map the source file's blocks into the donor file. */
1319			xfs_bmap_map_extent(tp, tip, &irec);
1320
1321			error = xfs_defer_finish(tpp);
1322			tp = *tpp;
1323			if (error)
1324				goto out;
1325
1326			tirec.br_startoff += rlen;
1327			if (tirec.br_startblock != HOLESTARTBLOCK &&
1328			    tirec.br_startblock != DELAYSTARTBLOCK)
1329				tirec.br_startblock += rlen;
1330			tirec.br_blockcount -= rlen;
1331		}
1332
1333		/* Roll on... */
1334		count_fsb -= ilen;
1335		offset_fsb += ilen;
1336	}
1337
1338	tip->i_diflags2 = tip_flags2;
1339	return 0;
1340
1341out:
1342	trace_xfs_swap_extent_rmap_error(ip, error, _RET_IP_);
1343	tip->i_diflags2 = tip_flags2;
1344	return error;
1345}
1346
1347/* Swap the extents of two files by swapping data forks. */
1348STATIC int
1349xfs_swap_extent_forks(
1350	struct xfs_trans	*tp,
1351	struct xfs_inode	*ip,
1352	struct xfs_inode	*tip,
1353	int			*src_log_flags,
1354	int			*target_log_flags)
1355{
1356	xfs_filblks_t		aforkblks = 0;
1357	xfs_filblks_t		taforkblks = 0;
1358	xfs_extnum_t		junk;
1359	uint64_t		tmp;
1360	int			error;
1361
1362	/*
1363	 * Count the number of extended attribute blocks
1364	 */
1365	if (xfs_inode_has_attr_fork(ip) && ip->i_af.if_nextents > 0 &&
1366	    ip->i_af.if_format != XFS_DINODE_FMT_LOCAL) {
1367		error = xfs_bmap_count_blocks(tp, ip, XFS_ATTR_FORK, &junk,
1368				&aforkblks);
1369		if (error)
1370			return error;
1371	}
1372	if (xfs_inode_has_attr_fork(tip) && tip->i_af.if_nextents > 0 &&
1373	    tip->i_af.if_format != XFS_DINODE_FMT_LOCAL) {
1374		error = xfs_bmap_count_blocks(tp, tip, XFS_ATTR_FORK, &junk,
1375				&taforkblks);
1376		if (error)
1377			return error;
1378	}
1379
1380	/*
1381	 * Btree format (v3) inodes have the inode number stamped in the bmbt
1382	 * block headers. We can't start changing the bmbt blocks until the
1383	 * inode owner change is logged so recovery does the right thing in the
1384	 * event of a crash. Set the owner change log flags now and leave the
1385	 * bmbt scan as the last step.
1386	 */
1387	if (xfs_has_v3inodes(ip->i_mount)) {
1388		if (ip->i_df.if_format == XFS_DINODE_FMT_BTREE)
1389			(*target_log_flags) |= XFS_ILOG_DOWNER;
1390		if (tip->i_df.if_format == XFS_DINODE_FMT_BTREE)
1391			(*src_log_flags) |= XFS_ILOG_DOWNER;
1392	}
1393
1394	/*
1395	 * Swap the data forks of the inodes
1396	 */
1397	swap(ip->i_df, tip->i_df);
1398
1399	/*
1400	 * Fix the on-disk inode values
1401	 */
1402	tmp = (uint64_t)ip->i_nblocks;
1403	ip->i_nblocks = tip->i_nblocks - taforkblks + aforkblks;
1404	tip->i_nblocks = tmp + taforkblks - aforkblks;
1405
1406	/*
1407	 * The extents in the source inode could still contain speculative
1408	 * preallocation beyond EOF (e.g. the file is open but not modified
1409	 * while defrag is in progress). In that case, we need to copy over the
1410	 * number of delalloc blocks the data fork in the source inode is
1411	 * tracking beyond EOF so that when the fork is truncated away when the
1412	 * temporary inode is unlinked we don't underrun the i_delayed_blks
1413	 * counter on that inode.
1414	 */
1415	ASSERT(tip->i_delayed_blks == 0);
1416	tip->i_delayed_blks = ip->i_delayed_blks;
1417	ip->i_delayed_blks = 0;
1418
1419	switch (ip->i_df.if_format) {
1420	case XFS_DINODE_FMT_EXTENTS:
1421		(*src_log_flags) |= XFS_ILOG_DEXT;
1422		break;
1423	case XFS_DINODE_FMT_BTREE:
1424		ASSERT(!xfs_has_v3inodes(ip->i_mount) ||
1425		       (*src_log_flags & XFS_ILOG_DOWNER));
1426		(*src_log_flags) |= XFS_ILOG_DBROOT;
1427		break;
1428	}
1429
1430	switch (tip->i_df.if_format) {
1431	case XFS_DINODE_FMT_EXTENTS:
1432		(*target_log_flags) |= XFS_ILOG_DEXT;
1433		break;
1434	case XFS_DINODE_FMT_BTREE:
1435		(*target_log_flags) |= XFS_ILOG_DBROOT;
1436		ASSERT(!xfs_has_v3inodes(ip->i_mount) ||
1437		       (*target_log_flags & XFS_ILOG_DOWNER));
1438		break;
1439	}
1440
1441	return 0;
1442}
1443
1444/*
1445 * Fix up the owners of the bmbt blocks to refer to the current inode. The
1446 * change owner scan attempts to order all modified buffers in the current
1447 * transaction. In the event of ordered buffer failure, the offending buffer is
1448 * physically logged as a fallback and the scan returns -EAGAIN. We must roll
1449 * the transaction in this case to replenish the fallback log reservation and
1450 * restart the scan. This process repeats until the scan completes.
1451 */
1452static int
1453xfs_swap_change_owner(
1454	struct xfs_trans	**tpp,
1455	struct xfs_inode	*ip,
1456	struct xfs_inode	*tmpip)
1457{
1458	int			error;
1459	struct xfs_trans	*tp = *tpp;
1460
1461	do {
1462		error = xfs_bmbt_change_owner(tp, ip, XFS_DATA_FORK, ip->i_ino,
1463					      NULL);
1464		/* success or fatal error */
1465		if (error != -EAGAIN)
1466			break;
1467
1468		error = xfs_trans_roll(tpp);
1469		if (error)
1470			break;
1471		tp = *tpp;
1472
1473		/*
1474		 * Redirty both inodes so they can relog and keep the log tail
1475		 * moving forward.
1476		 */
1477		xfs_trans_ijoin(tp, ip, 0);
1478		xfs_trans_ijoin(tp, tmpip, 0);
1479		xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
1480		xfs_trans_log_inode(tp, tmpip, XFS_ILOG_CORE);
1481	} while (true);
1482
1483	return error;
1484}
1485
1486int
1487xfs_swap_extents(
1488	struct xfs_inode	*ip,	/* target inode */
1489	struct xfs_inode	*tip,	/* tmp inode */
1490	struct xfs_swapext	*sxp)
1491{
1492	struct xfs_mount	*mp = ip->i_mount;
1493	struct xfs_trans	*tp;
1494	struct xfs_bstat	*sbp = &sxp->sx_stat;
1495	int			src_log_flags, target_log_flags;
1496	int			error = 0;
 
1497	uint64_t		f;
1498	int			resblks = 0;
1499	unsigned int		flags = 0;
1500	struct timespec64	ctime, mtime;
1501
1502	/*
1503	 * Lock the inodes against other IO, page faults and truncate to
1504	 * begin with.  Then we can ensure the inodes are flushed and have no
1505	 * page cache safely. Once we have done this we can take the ilocks and
1506	 * do the rest of the checks.
1507	 */
1508	lock_two_nondirectories(VFS_I(ip), VFS_I(tip));
1509	filemap_invalidate_lock_two(VFS_I(ip)->i_mapping,
1510				    VFS_I(tip)->i_mapping);
1511
1512	/* Verify that both files have the same format */
1513	if ((VFS_I(ip)->i_mode & S_IFMT) != (VFS_I(tip)->i_mode & S_IFMT)) {
1514		error = -EINVAL;
1515		goto out_unlock;
1516	}
1517
1518	/* Verify both files are either real-time or non-realtime */
1519	if (XFS_IS_REALTIME_INODE(ip) != XFS_IS_REALTIME_INODE(tip)) {
1520		error = -EINVAL;
1521		goto out_unlock;
1522	}
1523
1524	error = xfs_qm_dqattach(ip);
1525	if (error)
1526		goto out_unlock;
1527
1528	error = xfs_qm_dqattach(tip);
1529	if (error)
1530		goto out_unlock;
1531
1532	error = xfs_swap_extent_flush(ip);
1533	if (error)
1534		goto out_unlock;
1535	error = xfs_swap_extent_flush(tip);
1536	if (error)
1537		goto out_unlock;
1538
1539	if (xfs_inode_has_cow_data(tip)) {
1540		error = xfs_reflink_cancel_cow_range(tip, 0, NULLFILEOFF, true);
1541		if (error)
1542			goto out_unlock;
1543	}
1544
1545	/*
1546	 * Extent "swapping" with rmap requires a permanent reservation and
1547	 * a block reservation because it's really just a remap operation
1548	 * performed with log redo items!
1549	 */
1550	if (xfs_has_rmapbt(mp)) {
1551		int		w = XFS_DATA_FORK;
1552		uint32_t	ipnext = ip->i_df.if_nextents;
1553		uint32_t	tipnext	= tip->i_df.if_nextents;
1554
1555		/*
1556		 * Conceptually this shouldn't affect the shape of either bmbt,
1557		 * but since we atomically move extents one by one, we reserve
1558		 * enough space to rebuild both trees.
1559		 */
1560		resblks = XFS_SWAP_RMAP_SPACE_RES(mp, ipnext, w);
1561		resblks +=  XFS_SWAP_RMAP_SPACE_RES(mp, tipnext, w);
1562
1563		/*
1564		 * If either inode straddles a bmapbt block allocation boundary,
1565		 * the rmapbt algorithm triggers repeated allocs and frees as
1566		 * extents are remapped. This can exhaust the block reservation
1567		 * prematurely and cause shutdown. Return freed blocks to the
1568		 * transaction reservation to counter this behavior.
1569		 */
1570		flags |= XFS_TRANS_RES_FDBLKS;
1571	}
1572	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, 0, flags,
1573				&tp);
1574	if (error)
1575		goto out_unlock;
1576
1577	/*
1578	 * Lock and join the inodes to the tansaction so that transaction commit
1579	 * or cancel will unlock the inodes from this point onwards.
1580	 */
1581	xfs_lock_two_inodes(ip, XFS_ILOCK_EXCL, tip, XFS_ILOCK_EXCL);
 
1582	xfs_trans_ijoin(tp, ip, 0);
1583	xfs_trans_ijoin(tp, tip, 0);
1584
1585
1586	/* Verify all data are being swapped */
1587	if (sxp->sx_offset != 0 ||
1588	    sxp->sx_length != ip->i_disk_size ||
1589	    sxp->sx_length != tip->i_disk_size) {
1590		error = -EFAULT;
1591		goto out_trans_cancel;
1592	}
1593
1594	trace_xfs_swap_extent_before(ip, 0);
1595	trace_xfs_swap_extent_before(tip, 1);
1596
1597	/* check inode formats now that data is flushed */
1598	error = xfs_swap_extents_check_format(ip, tip);
1599	if (error) {
1600		xfs_notice(mp,
1601		    "%s: inode 0x%llx format is incompatible for exchanging.",
1602				__func__, ip->i_ino);
1603		goto out_trans_cancel;
1604	}
1605
1606	/*
1607	 * Compare the current change & modify times with that
1608	 * passed in.  If they differ, we abort this swap.
1609	 * This is the mechanism used to ensure the calling
1610	 * process that the file was not changed out from
1611	 * under it.
1612	 */
1613	ctime = inode_get_ctime(VFS_I(ip));
1614	mtime = inode_get_mtime(VFS_I(ip));
1615	if ((sbp->bs_ctime.tv_sec != ctime.tv_sec) ||
1616	    (sbp->bs_ctime.tv_nsec != ctime.tv_nsec) ||
1617	    (sbp->bs_mtime.tv_sec != mtime.tv_sec) ||
1618	    (sbp->bs_mtime.tv_nsec != mtime.tv_nsec)) {
1619		error = -EBUSY;
1620		goto out_trans_cancel;
1621	}
1622
1623	/*
1624	 * Note the trickiness in setting the log flags - we set the owner log
1625	 * flag on the opposite inode (i.e. the inode we are setting the new
1626	 * owner to be) because once we swap the forks and log that, log
1627	 * recovery is going to see the fork as owned by the swapped inode,
1628	 * not the pre-swapped inodes.
1629	 */
1630	src_log_flags = XFS_ILOG_CORE;
1631	target_log_flags = XFS_ILOG_CORE;
1632
1633	if (xfs_has_rmapbt(mp))
1634		error = xfs_swap_extent_rmap(&tp, ip, tip);
1635	else
1636		error = xfs_swap_extent_forks(tp, ip, tip, &src_log_flags,
1637				&target_log_flags);
1638	if (error)
1639		goto out_trans_cancel;
1640
1641	/* Do we have to swap reflink flags? */
1642	if ((ip->i_diflags2 & XFS_DIFLAG2_REFLINK) ^
1643	    (tip->i_diflags2 & XFS_DIFLAG2_REFLINK)) {
1644		f = ip->i_diflags2 & XFS_DIFLAG2_REFLINK;
1645		ip->i_diflags2 &= ~XFS_DIFLAG2_REFLINK;
1646		ip->i_diflags2 |= tip->i_diflags2 & XFS_DIFLAG2_REFLINK;
1647		tip->i_diflags2 &= ~XFS_DIFLAG2_REFLINK;
1648		tip->i_diflags2 |= f & XFS_DIFLAG2_REFLINK;
1649	}
1650
1651	/* Swap the cow forks. */
1652	if (xfs_has_reflink(mp)) {
1653		ASSERT(!ip->i_cowfp ||
1654		       ip->i_cowfp->if_format == XFS_DINODE_FMT_EXTENTS);
1655		ASSERT(!tip->i_cowfp ||
1656		       tip->i_cowfp->if_format == XFS_DINODE_FMT_EXTENTS);
1657
1658		swap(ip->i_cowfp, tip->i_cowfp);
1659
1660		if (ip->i_cowfp && ip->i_cowfp->if_bytes)
1661			xfs_inode_set_cowblocks_tag(ip);
1662		else
1663			xfs_inode_clear_cowblocks_tag(ip);
1664		if (tip->i_cowfp && tip->i_cowfp->if_bytes)
1665			xfs_inode_set_cowblocks_tag(tip);
1666		else
1667			xfs_inode_clear_cowblocks_tag(tip);
1668	}
1669
1670	xfs_trans_log_inode(tp, ip,  src_log_flags);
1671	xfs_trans_log_inode(tp, tip, target_log_flags);
1672
1673	/*
1674	 * The extent forks have been swapped, but crc=1,rmapbt=0 filesystems
1675	 * have inode number owner values in the bmbt blocks that still refer to
1676	 * the old inode. Scan each bmbt to fix up the owner values with the
1677	 * inode number of the current inode.
1678	 */
1679	if (src_log_flags & XFS_ILOG_DOWNER) {
1680		error = xfs_swap_change_owner(&tp, ip, tip);
1681		if (error)
1682			goto out_trans_cancel;
1683	}
1684	if (target_log_flags & XFS_ILOG_DOWNER) {
1685		error = xfs_swap_change_owner(&tp, tip, ip);
1686		if (error)
1687			goto out_trans_cancel;
1688	}
1689
1690	/*
1691	 * If this is a synchronous mount, make sure that the
1692	 * transaction goes to disk before returning to the user.
1693	 */
1694	if (xfs_has_wsync(mp))
1695		xfs_trans_set_sync(tp);
1696
1697	error = xfs_trans_commit(tp);
1698
1699	trace_xfs_swap_extent_after(ip, 0);
1700	trace_xfs_swap_extent_after(tip, 1);
1701
1702out_unlock_ilock:
1703	xfs_iunlock(ip, XFS_ILOCK_EXCL);
1704	xfs_iunlock(tip, XFS_ILOCK_EXCL);
1705out_unlock:
1706	filemap_invalidate_unlock_two(VFS_I(ip)->i_mapping,
1707				      VFS_I(tip)->i_mapping);
1708	unlock_two_nondirectories(VFS_I(ip), VFS_I(tip));
1709	return error;
1710
1711out_trans_cancel:
1712	xfs_trans_cancel(tp);
1713	goto out_unlock_ilock;
1714}