xref: /openbmc/linux/fs/xfs/xfs_bmap_util.c (revision 83146efc)
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 
32 /* Kernel only BMAP related definitions and functions */
33 
34 /*
35  * Convert the given file system block to a disk block.  We have to treat it
36  * differently based on whether the file is a real time file or not, because the
37  * bmap code does.
38  */
39 xfs_daddr_t
40 xfs_fsb_to_db(struct xfs_inode *ip, xfs_fsblock_t fsb)
41 {
42 	if (XFS_IS_REALTIME_INODE(ip))
43 		return XFS_FSB_TO_BB(ip->i_mount, fsb);
44 	return XFS_FSB_TO_DADDR(ip->i_mount, fsb);
45 }
46 
47 /*
48  * Routine to zero an extent on disk allocated to the specific inode.
49  *
50  * The VFS functions take a linearised filesystem block offset, so we have to
51  * convert the sparse xfs fsb to the right format first.
52  * VFS types are real funky, too.
53  */
54 int
55 xfs_zero_extent(
56 	struct xfs_inode	*ip,
57 	xfs_fsblock_t		start_fsb,
58 	xfs_off_t		count_fsb)
59 {
60 	struct xfs_mount	*mp = ip->i_mount;
61 	struct xfs_buftarg	*target = xfs_inode_buftarg(ip);
62 	xfs_daddr_t		sector = xfs_fsb_to_db(ip, start_fsb);
63 	sector_t		block = XFS_BB_TO_FSBT(mp, sector);
64 
65 	return blkdev_issue_zeroout(target->bt_bdev,
66 		block << (mp->m_super->s_blocksize_bits - 9),
67 		count_fsb << (mp->m_super->s_blocksize_bits - 9),
68 		GFP_NOFS, 0);
69 }
70 
71 #ifdef CONFIG_XFS_RT
72 int
73 xfs_bmap_rtalloc(
74 	struct xfs_bmalloca	*ap)
75 {
76 	struct xfs_mount	*mp = ap->ip->i_mount;
77 	xfs_fileoff_t		orig_offset = ap->offset;
78 	xfs_rtblock_t		rtb;
79 	xfs_extlen_t		prod = 0;  /* product factor for allocators */
80 	xfs_extlen_t		mod = 0;   /* product factor for allocators */
81 	xfs_extlen_t		ralen = 0; /* realtime allocation length */
82 	xfs_extlen_t		align;     /* minimum allocation alignment */
83 	xfs_extlen_t		orig_length = ap->length;
84 	xfs_extlen_t		minlen = mp->m_sb.sb_rextsize;
85 	xfs_extlen_t		raminlen;
86 	bool			rtlocked = false;
87 	bool			ignore_locality = false;
88 	int			error;
89 
90 	align = xfs_get_extsz_hint(ap->ip);
91 retry:
92 	prod = align / mp->m_sb.sb_rextsize;
93 	error = xfs_bmap_extsize_align(mp, &ap->got, &ap->prev,
94 					align, 1, ap->eof, 0,
95 					ap->conv, &ap->offset, &ap->length);
96 	if (error)
97 		return error;
98 	ASSERT(ap->length);
99 	ASSERT(ap->length % mp->m_sb.sb_rextsize == 0);
100 
101 	/*
102 	 * If we shifted the file offset downward to satisfy an extent size
103 	 * hint, increase minlen by that amount so that the allocator won't
104 	 * give us an allocation that's too short to cover at least one of the
105 	 * blocks that the caller asked for.
106 	 */
107 	if (ap->offset != orig_offset)
108 		minlen += orig_offset - ap->offset;
109 
110 	/*
111 	 * If the offset & length are not perfectly aligned
112 	 * then kill prod, it will just get us in trouble.
113 	 */
114 	div_u64_rem(ap->offset, align, &mod);
115 	if (mod || ap->length % align)
116 		prod = 1;
117 	/*
118 	 * Set ralen to be the actual requested length in rtextents.
119 	 */
120 	ralen = ap->length / mp->m_sb.sb_rextsize;
121 	/*
122 	 * If the old value was close enough to XFS_BMBT_MAX_EXTLEN that
123 	 * we rounded up to it, cut it back so it's valid again.
124 	 * Note that if it's a really large request (bigger than
125 	 * XFS_BMBT_MAX_EXTLEN), we don't hear about that number, and can't
126 	 * adjust the starting point to match it.
127 	 */
128 	if (ralen * mp->m_sb.sb_rextsize >= XFS_MAX_BMBT_EXTLEN)
129 		ralen = XFS_MAX_BMBT_EXTLEN / mp->m_sb.sb_rextsize;
130 
131 	/*
132 	 * Lock out modifications to both the RT bitmap and summary inodes
133 	 */
134 	if (!rtlocked) {
135 		xfs_ilock(mp->m_rbmip, XFS_ILOCK_EXCL|XFS_ILOCK_RTBITMAP);
136 		xfs_trans_ijoin(ap->tp, mp->m_rbmip, XFS_ILOCK_EXCL);
137 		xfs_ilock(mp->m_rsumip, XFS_ILOCK_EXCL|XFS_ILOCK_RTSUM);
138 		xfs_trans_ijoin(ap->tp, mp->m_rsumip, XFS_ILOCK_EXCL);
139 		rtlocked = true;
140 	}
141 
142 	/*
143 	 * If it's an allocation to an empty file at offset 0,
144 	 * pick an extent that will space things out in the rt area.
145 	 */
146 	if (ap->eof && ap->offset == 0) {
147 		xfs_rtblock_t rtx; /* realtime extent no */
148 
149 		error = xfs_rtpick_extent(mp, ap->tp, ralen, &rtx);
150 		if (error)
151 			return error;
152 		ap->blkno = rtx * mp->m_sb.sb_rextsize;
153 	} else {
154 		ap->blkno = 0;
155 	}
156 
157 	xfs_bmap_adjacent(ap);
158 
159 	/*
160 	 * Realtime allocation, done through xfs_rtallocate_extent.
161 	 */
162 	if (ignore_locality)
163 		ap->blkno = 0;
164 	else
165 		do_div(ap->blkno, mp->m_sb.sb_rextsize);
166 	rtb = ap->blkno;
167 	ap->length = ralen;
168 	raminlen = max_t(xfs_extlen_t, 1, minlen / mp->m_sb.sb_rextsize);
169 	error = xfs_rtallocate_extent(ap->tp, ap->blkno, raminlen, ap->length,
170 			&ralen, ap->wasdel, prod, &rtb);
171 	if (error)
172 		return error;
173 
174 	if (rtb != NULLRTBLOCK) {
175 		ap->blkno = rtb * mp->m_sb.sb_rextsize;
176 		ap->length = ralen * mp->m_sb.sb_rextsize;
177 		ap->ip->i_nblocks += ap->length;
178 		xfs_trans_log_inode(ap->tp, ap->ip, XFS_ILOG_CORE);
179 		if (ap->wasdel)
180 			ap->ip->i_delayed_blks -= ap->length;
181 		/*
182 		 * Adjust the disk quota also. This was reserved
183 		 * earlier.
184 		 */
185 		xfs_trans_mod_dquot_byino(ap->tp, ap->ip,
186 			ap->wasdel ? XFS_TRANS_DQ_DELRTBCOUNT :
187 					XFS_TRANS_DQ_RTBCOUNT, ap->length);
188 		return 0;
189 	}
190 
191 	if (align > mp->m_sb.sb_rextsize) {
192 		/*
193 		 * We previously enlarged the request length to try to satisfy
194 		 * an extent size hint.  The allocator didn't return anything,
195 		 * so reset the parameters to the original values and try again
196 		 * without alignment criteria.
197 		 */
198 		ap->offset = orig_offset;
199 		ap->length = orig_length;
200 		minlen = align = mp->m_sb.sb_rextsize;
201 		goto retry;
202 	}
203 
204 	if (!ignore_locality && ap->blkno != 0) {
205 		/*
206 		 * If we can't allocate near a specific rt extent, try again
207 		 * without locality criteria.
208 		 */
209 		ignore_locality = true;
210 		goto retry;
211 	}
212 
213 	ap->blkno = NULLFSBLOCK;
214 	ap->length = 0;
215 	return 0;
216 }
217 #endif /* CONFIG_XFS_RT */
218 
219 /*
220  * Extent tree block counting routines.
221  */
222 
223 /*
224  * Count leaf blocks given a range of extent records.  Delayed allocation
225  * extents are not counted towards the totals.
226  */
227 xfs_extnum_t
228 xfs_bmap_count_leaves(
229 	struct xfs_ifork	*ifp,
230 	xfs_filblks_t		*count)
231 {
232 	struct xfs_iext_cursor	icur;
233 	struct xfs_bmbt_irec	got;
234 	xfs_extnum_t		numrecs = 0;
235 
236 	for_each_xfs_iext(ifp, &icur, &got) {
237 		if (!isnullstartblock(got.br_startblock)) {
238 			*count += got.br_blockcount;
239 			numrecs++;
240 		}
241 	}
242 
243 	return numrecs;
244 }
245 
246 /*
247  * Count fsblocks of the given fork.  Delayed allocation extents are
248  * not counted towards the totals.
249  */
250 int
251 xfs_bmap_count_blocks(
252 	struct xfs_trans	*tp,
253 	struct xfs_inode	*ip,
254 	int			whichfork,
255 	xfs_extnum_t		*nextents,
256 	xfs_filblks_t		*count)
257 {
258 	struct xfs_mount	*mp = ip->i_mount;
259 	struct xfs_ifork	*ifp = xfs_ifork_ptr(ip, whichfork);
260 	struct xfs_btree_cur	*cur;
261 	xfs_extlen_t		btblocks = 0;
262 	int			error;
263 
264 	*nextents = 0;
265 	*count = 0;
266 
267 	if (!ifp)
268 		return 0;
269 
270 	switch (ifp->if_format) {
271 	case XFS_DINODE_FMT_BTREE:
272 		error = xfs_iread_extents(tp, ip, whichfork);
273 		if (error)
274 			return error;
275 
276 		cur = xfs_bmbt_init_cursor(mp, tp, ip, whichfork);
277 		error = xfs_btree_count_blocks(cur, &btblocks);
278 		xfs_btree_del_cursor(cur, error);
279 		if (error)
280 			return error;
281 
282 		/*
283 		 * xfs_btree_count_blocks includes the root block contained in
284 		 * the inode fork in @btblocks, so subtract one because we're
285 		 * only interested in allocated disk blocks.
286 		 */
287 		*count += btblocks - 1;
288 
289 		fallthrough;
290 	case XFS_DINODE_FMT_EXTENTS:
291 		*nextents = xfs_bmap_count_leaves(ifp, count);
292 		break;
293 	}
294 
295 	return 0;
296 }
297 
298 static int
299 xfs_getbmap_report_one(
300 	struct xfs_inode	*ip,
301 	struct getbmapx		*bmv,
302 	struct kgetbmap		*out,
303 	int64_t			bmv_end,
304 	struct xfs_bmbt_irec	*got)
305 {
306 	struct kgetbmap		*p = out + bmv->bmv_entries;
307 	bool			shared = false;
308 	int			error;
309 
310 	error = xfs_reflink_trim_around_shared(ip, got, &shared);
311 	if (error)
312 		return error;
313 
314 	if (isnullstartblock(got->br_startblock) ||
315 	    got->br_startblock == DELAYSTARTBLOCK) {
316 		/*
317 		 * Take the flush completion as being a point-in-time snapshot
318 		 * where there are no delalloc extents, and if any new ones
319 		 * have been created racily, just skip them as being 'after'
320 		 * the flush and so don't get reported.
321 		 */
322 		if (!(bmv->bmv_iflags & BMV_IF_DELALLOC))
323 			return 0;
324 
325 		p->bmv_oflags |= BMV_OF_DELALLOC;
326 		p->bmv_block = -2;
327 	} else {
328 		p->bmv_block = xfs_fsb_to_db(ip, got->br_startblock);
329 	}
330 
331 	if (got->br_state == XFS_EXT_UNWRITTEN &&
332 	    (bmv->bmv_iflags & BMV_IF_PREALLOC))
333 		p->bmv_oflags |= BMV_OF_PREALLOC;
334 
335 	if (shared)
336 		p->bmv_oflags |= BMV_OF_SHARED;
337 
338 	p->bmv_offset = XFS_FSB_TO_BB(ip->i_mount, got->br_startoff);
339 	p->bmv_length = XFS_FSB_TO_BB(ip->i_mount, got->br_blockcount);
340 
341 	bmv->bmv_offset = p->bmv_offset + p->bmv_length;
342 	bmv->bmv_length = max(0LL, bmv_end - bmv->bmv_offset);
343 	bmv->bmv_entries++;
344 	return 0;
345 }
346 
347 static void
348 xfs_getbmap_report_hole(
349 	struct xfs_inode	*ip,
350 	struct getbmapx		*bmv,
351 	struct kgetbmap		*out,
352 	int64_t			bmv_end,
353 	xfs_fileoff_t		bno,
354 	xfs_fileoff_t		end)
355 {
356 	struct kgetbmap		*p = out + bmv->bmv_entries;
357 
358 	if (bmv->bmv_iflags & BMV_IF_NO_HOLES)
359 		return;
360 
361 	p->bmv_block = -1;
362 	p->bmv_offset = XFS_FSB_TO_BB(ip->i_mount, bno);
363 	p->bmv_length = XFS_FSB_TO_BB(ip->i_mount, end - bno);
364 
365 	bmv->bmv_offset = p->bmv_offset + p->bmv_length;
366 	bmv->bmv_length = max(0LL, bmv_end - bmv->bmv_offset);
367 	bmv->bmv_entries++;
368 }
369 
370 static inline bool
371 xfs_getbmap_full(
372 	struct getbmapx		*bmv)
373 {
374 	return bmv->bmv_length == 0 || bmv->bmv_entries >= bmv->bmv_count - 1;
375 }
376 
377 static bool
378 xfs_getbmap_next_rec(
379 	struct xfs_bmbt_irec	*rec,
380 	xfs_fileoff_t		total_end)
381 {
382 	xfs_fileoff_t		end = rec->br_startoff + rec->br_blockcount;
383 
384 	if (end == total_end)
385 		return false;
386 
387 	rec->br_startoff += rec->br_blockcount;
388 	if (!isnullstartblock(rec->br_startblock) &&
389 	    rec->br_startblock != DELAYSTARTBLOCK)
390 		rec->br_startblock += rec->br_blockcount;
391 	rec->br_blockcount = total_end - end;
392 	return true;
393 }
394 
395 /*
396  * Get inode's extents as described in bmv, and format for output.
397  * Calls formatter to fill the user's buffer until all extents
398  * are mapped, until the passed-in bmv->bmv_count slots have
399  * been filled, or until the formatter short-circuits the loop,
400  * if it is tracking filled-in extents on its own.
401  */
402 int						/* error code */
403 xfs_getbmap(
404 	struct xfs_inode	*ip,
405 	struct getbmapx		*bmv,		/* user bmap structure */
406 	struct kgetbmap		*out)
407 {
408 	struct xfs_mount	*mp = ip->i_mount;
409 	int			iflags = bmv->bmv_iflags;
410 	int			whichfork, lock, error = 0;
411 	int64_t			bmv_end, max_len;
412 	xfs_fileoff_t		bno, first_bno;
413 	struct xfs_ifork	*ifp;
414 	struct xfs_bmbt_irec	got, rec;
415 	xfs_filblks_t		len;
416 	struct xfs_iext_cursor	icur;
417 
418 	if (bmv->bmv_iflags & ~BMV_IF_VALID)
419 		return -EINVAL;
420 #ifndef DEBUG
421 	/* Only allow CoW fork queries if we're debugging. */
422 	if (iflags & BMV_IF_COWFORK)
423 		return -EINVAL;
424 #endif
425 	if ((iflags & BMV_IF_ATTRFORK) && (iflags & BMV_IF_COWFORK))
426 		return -EINVAL;
427 
428 	if (bmv->bmv_length < -1)
429 		return -EINVAL;
430 	bmv->bmv_entries = 0;
431 	if (bmv->bmv_length == 0)
432 		return 0;
433 
434 	if (iflags & BMV_IF_ATTRFORK)
435 		whichfork = XFS_ATTR_FORK;
436 	else if (iflags & BMV_IF_COWFORK)
437 		whichfork = XFS_COW_FORK;
438 	else
439 		whichfork = XFS_DATA_FORK;
440 
441 	xfs_ilock(ip, XFS_IOLOCK_SHARED);
442 	switch (whichfork) {
443 	case XFS_ATTR_FORK:
444 		lock = xfs_ilock_attr_map_shared(ip);
445 		if (!xfs_inode_has_attr_fork(ip))
446 			goto out_unlock_ilock;
447 
448 		max_len = 1LL << 32;
449 		break;
450 	case XFS_COW_FORK:
451 		lock = XFS_ILOCK_SHARED;
452 		xfs_ilock(ip, lock);
453 
454 		/* No CoW fork? Just return */
455 		if (!xfs_ifork_ptr(ip, whichfork))
456 			goto out_unlock_ilock;
457 
458 		if (xfs_get_cowextsz_hint(ip))
459 			max_len = mp->m_super->s_maxbytes;
460 		else
461 			max_len = XFS_ISIZE(ip);
462 		break;
463 	case XFS_DATA_FORK:
464 		if (!(iflags & BMV_IF_DELALLOC) &&
465 		    (ip->i_delayed_blks || XFS_ISIZE(ip) > ip->i_disk_size)) {
466 			error = filemap_write_and_wait(VFS_I(ip)->i_mapping);
467 			if (error)
468 				goto out_unlock_iolock;
469 
470 			/*
471 			 * Even after flushing the inode, there can still be
472 			 * delalloc blocks on the inode beyond EOF due to
473 			 * speculative preallocation.  These are not removed
474 			 * until the release function is called or the inode
475 			 * is inactivated.  Hence we cannot assert here that
476 			 * ip->i_delayed_blks == 0.
477 			 */
478 		}
479 
480 		if (xfs_get_extsz_hint(ip) ||
481 		    (ip->i_diflags &
482 		     (XFS_DIFLAG_PREALLOC | XFS_DIFLAG_APPEND)))
483 			max_len = mp->m_super->s_maxbytes;
484 		else
485 			max_len = XFS_ISIZE(ip);
486 
487 		lock = xfs_ilock_data_map_shared(ip);
488 		break;
489 	}
490 
491 	ifp = xfs_ifork_ptr(ip, whichfork);
492 
493 	switch (ifp->if_format) {
494 	case XFS_DINODE_FMT_EXTENTS:
495 	case XFS_DINODE_FMT_BTREE:
496 		break;
497 	case XFS_DINODE_FMT_LOCAL:
498 		/* Local format inode forks report no extents. */
499 		goto out_unlock_ilock;
500 	default:
501 		error = -EINVAL;
502 		goto out_unlock_ilock;
503 	}
504 
505 	if (bmv->bmv_length == -1) {
506 		max_len = XFS_FSB_TO_BB(mp, XFS_B_TO_FSB(mp, max_len));
507 		bmv->bmv_length = max(0LL, max_len - bmv->bmv_offset);
508 	}
509 
510 	bmv_end = bmv->bmv_offset + bmv->bmv_length;
511 
512 	first_bno = bno = XFS_BB_TO_FSBT(mp, bmv->bmv_offset);
513 	len = XFS_BB_TO_FSB(mp, bmv->bmv_length);
514 
515 	error = xfs_iread_extents(NULL, ip, whichfork);
516 	if (error)
517 		goto out_unlock_ilock;
518 
519 	if (!xfs_iext_lookup_extent(ip, ifp, bno, &icur, &got)) {
520 		/*
521 		 * Report a whole-file hole if the delalloc flag is set to
522 		 * stay compatible with the old implementation.
523 		 */
524 		if (iflags & BMV_IF_DELALLOC)
525 			xfs_getbmap_report_hole(ip, bmv, out, bmv_end, bno,
526 					XFS_B_TO_FSB(mp, XFS_ISIZE(ip)));
527 		goto out_unlock_ilock;
528 	}
529 
530 	while (!xfs_getbmap_full(bmv)) {
531 		xfs_trim_extent(&got, first_bno, len);
532 
533 		/*
534 		 * Report an entry for a hole if this extent doesn't directly
535 		 * follow the previous one.
536 		 */
537 		if (got.br_startoff > bno) {
538 			xfs_getbmap_report_hole(ip, bmv, out, bmv_end, bno,
539 					got.br_startoff);
540 			if (xfs_getbmap_full(bmv))
541 				break;
542 		}
543 
544 		/*
545 		 * In order to report shared extents accurately, we report each
546 		 * distinct shared / unshared part of a single bmbt record with
547 		 * an individual getbmapx record.
548 		 */
549 		bno = got.br_startoff + got.br_blockcount;
550 		rec = got;
551 		do {
552 			error = xfs_getbmap_report_one(ip, bmv, out, bmv_end,
553 					&rec);
554 			if (error || xfs_getbmap_full(bmv))
555 				goto out_unlock_ilock;
556 		} while (xfs_getbmap_next_rec(&rec, bno));
557 
558 		if (!xfs_iext_next_extent(ifp, &icur, &got)) {
559 			xfs_fileoff_t	end = XFS_B_TO_FSB(mp, XFS_ISIZE(ip));
560 
561 			if (bmv->bmv_entries > 0)
562 				out[bmv->bmv_entries - 1].bmv_oflags |=
563 								BMV_OF_LAST;
564 
565 			if (whichfork != XFS_ATTR_FORK && bno < end &&
566 			    !xfs_getbmap_full(bmv)) {
567 				xfs_getbmap_report_hole(ip, bmv, out, bmv_end,
568 						bno, end);
569 			}
570 			break;
571 		}
572 
573 		if (bno >= first_bno + len)
574 			break;
575 	}
576 
577 out_unlock_ilock:
578 	xfs_iunlock(ip, lock);
579 out_unlock_iolock:
580 	xfs_iunlock(ip, XFS_IOLOCK_SHARED);
581 	return error;
582 }
583 
584 /*
585  * Dead simple method of punching delalyed allocation blocks from a range in
586  * the inode.  This will always punch out both the start and end blocks, even
587  * if the ranges only partially overlap them, so it is up to the caller to
588  * ensure that partial blocks are not passed in.
589  */
590 int
591 xfs_bmap_punch_delalloc_range(
592 	struct xfs_inode	*ip,
593 	xfs_off_t		start_byte,
594 	xfs_off_t		end_byte)
595 {
596 	struct xfs_mount	*mp = ip->i_mount;
597 	struct xfs_ifork	*ifp = &ip->i_df;
598 	xfs_fileoff_t		start_fsb = XFS_B_TO_FSBT(mp, start_byte);
599 	xfs_fileoff_t		end_fsb = XFS_B_TO_FSB(mp, end_byte);
600 	struct xfs_bmbt_irec	got, del;
601 	struct xfs_iext_cursor	icur;
602 	int			error = 0;
603 
604 	ASSERT(!xfs_need_iread_extents(ifp));
605 
606 	xfs_ilock(ip, XFS_ILOCK_EXCL);
607 	if (!xfs_iext_lookup_extent_before(ip, ifp, &end_fsb, &icur, &got))
608 		goto out_unlock;
609 
610 	while (got.br_startoff + got.br_blockcount > start_fsb) {
611 		del = got;
612 		xfs_trim_extent(&del, start_fsb, end_fsb - start_fsb);
613 
614 		/*
615 		 * A delete can push the cursor forward. Step back to the
616 		 * previous extent on non-delalloc or extents outside the
617 		 * target range.
618 		 */
619 		if (!del.br_blockcount ||
620 		    !isnullstartblock(del.br_startblock)) {
621 			if (!xfs_iext_prev_extent(ifp, &icur, &got))
622 				break;
623 			continue;
624 		}
625 
626 		error = xfs_bmap_del_extent_delay(ip, XFS_DATA_FORK, &icur,
627 						  &got, &del);
628 		if (error || !xfs_iext_get_extent(ifp, &icur, &got))
629 			break;
630 	}
631 
632 out_unlock:
633 	xfs_iunlock(ip, XFS_ILOCK_EXCL);
634 	return error;
635 }
636 
637 /*
638  * Test whether it is appropriate to check an inode for and free post EOF
639  * blocks. The 'force' parameter determines whether we should also consider
640  * regular files that are marked preallocated or append-only.
641  */
642 bool
643 xfs_can_free_eofblocks(
644 	struct xfs_inode	*ip,
645 	bool			force)
646 {
647 	struct xfs_bmbt_irec	imap;
648 	struct xfs_mount	*mp = ip->i_mount;
649 	xfs_fileoff_t		end_fsb;
650 	xfs_fileoff_t		last_fsb;
651 	int			nimaps = 1;
652 	int			error;
653 
654 	/*
655 	 * Caller must either hold the exclusive io lock; or be inactivating
656 	 * the inode, which guarantees there are no other users of the inode.
657 	 */
658 	ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL) ||
659 	       (VFS_I(ip)->i_state & I_FREEING));
660 
661 	/* prealloc/delalloc exists only on regular files */
662 	if (!S_ISREG(VFS_I(ip)->i_mode))
663 		return false;
664 
665 	/*
666 	 * Zero sized files with no cached pages and delalloc blocks will not
667 	 * have speculative prealloc/delalloc blocks to remove.
668 	 */
669 	if (VFS_I(ip)->i_size == 0 &&
670 	    VFS_I(ip)->i_mapping->nrpages == 0 &&
671 	    ip->i_delayed_blks == 0)
672 		return false;
673 
674 	/* If we haven't read in the extent list, then don't do it now. */
675 	if (xfs_need_iread_extents(&ip->i_df))
676 		return false;
677 
678 	/*
679 	 * Do not free real preallocated or append-only files unless the file
680 	 * has delalloc blocks and we are forced to remove them.
681 	 */
682 	if (ip->i_diflags & (XFS_DIFLAG_PREALLOC | XFS_DIFLAG_APPEND))
683 		if (!force || ip->i_delayed_blks == 0)
684 			return false;
685 
686 	/*
687 	 * Do not try to free post-EOF blocks if EOF is beyond the end of the
688 	 * range supported by the page cache, because the truncation will loop
689 	 * forever.
690 	 */
691 	end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)XFS_ISIZE(ip));
692 	if (XFS_IS_REALTIME_INODE(ip) && mp->m_sb.sb_rextsize > 1)
693 		end_fsb = roundup_64(end_fsb, mp->m_sb.sb_rextsize);
694 	last_fsb = XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes);
695 	if (last_fsb <= end_fsb)
696 		return false;
697 
698 	/*
699 	 * Look up the mapping for the first block past EOF.  If we can't find
700 	 * it, there's nothing to free.
701 	 */
702 	xfs_ilock(ip, XFS_ILOCK_SHARED);
703 	error = xfs_bmapi_read(ip, end_fsb, last_fsb - end_fsb, &imap, &nimaps,
704 			0);
705 	xfs_iunlock(ip, XFS_ILOCK_SHARED);
706 	if (error || nimaps == 0)
707 		return false;
708 
709 	/*
710 	 * If there's a real mapping there or there are delayed allocation
711 	 * reservations, then we have post-EOF blocks to try to free.
712 	 */
713 	return imap.br_startblock != HOLESTARTBLOCK || ip->i_delayed_blks;
714 }
715 
716 /*
717  * This is called to free any blocks beyond eof. The caller must hold
718  * IOLOCK_EXCL unless we are in the inode reclaim path and have the only
719  * reference to the inode.
720  */
721 int
722 xfs_free_eofblocks(
723 	struct xfs_inode	*ip)
724 {
725 	struct xfs_trans	*tp;
726 	struct xfs_mount	*mp = ip->i_mount;
727 	int			error;
728 
729 	/* Attach the dquots to the inode up front. */
730 	error = xfs_qm_dqattach(ip);
731 	if (error)
732 		return error;
733 
734 	/* Wait on dio to ensure i_size has settled. */
735 	inode_dio_wait(VFS_I(ip));
736 
737 	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate, 0, 0, 0, &tp);
738 	if (error) {
739 		ASSERT(xfs_is_shutdown(mp));
740 		return error;
741 	}
742 
743 	xfs_ilock(ip, XFS_ILOCK_EXCL);
744 	xfs_trans_ijoin(tp, ip, 0);
745 
746 	/*
747 	 * Do not update the on-disk file size.  If we update the on-disk file
748 	 * size and then the system crashes before the contents of the file are
749 	 * flushed to disk then the files may be full of holes (ie NULL files
750 	 * bug).
751 	 */
752 	error = xfs_itruncate_extents_flags(&tp, ip, XFS_DATA_FORK,
753 				XFS_ISIZE(ip), XFS_BMAPI_NODISCARD);
754 	if (error)
755 		goto err_cancel;
756 
757 	error = xfs_trans_commit(tp);
758 	if (error)
759 		goto out_unlock;
760 
761 	xfs_inode_clear_eofblocks_tag(ip);
762 	goto out_unlock;
763 
764 err_cancel:
765 	/*
766 	 * If we get an error at this point we simply don't
767 	 * bother truncating the file.
768 	 */
769 	xfs_trans_cancel(tp);
770 out_unlock:
771 	xfs_iunlock(ip, XFS_ILOCK_EXCL);
772 	return error;
773 }
774 
775 int
776 xfs_alloc_file_space(
777 	struct xfs_inode	*ip,
778 	xfs_off_t		offset,
779 	xfs_off_t		len)
780 {
781 	xfs_mount_t		*mp = ip->i_mount;
782 	xfs_off_t		count;
783 	xfs_filblks_t		allocated_fsb;
784 	xfs_filblks_t		allocatesize_fsb;
785 	xfs_extlen_t		extsz, temp;
786 	xfs_fileoff_t		startoffset_fsb;
787 	xfs_fileoff_t		endoffset_fsb;
788 	int			nimaps;
789 	int			rt;
790 	xfs_trans_t		*tp;
791 	xfs_bmbt_irec_t		imaps[1], *imapp;
792 	int			error;
793 
794 	trace_xfs_alloc_file_space(ip);
795 
796 	if (xfs_is_shutdown(mp))
797 		return -EIO;
798 
799 	error = xfs_qm_dqattach(ip);
800 	if (error)
801 		return error;
802 
803 	if (len <= 0)
804 		return -EINVAL;
805 
806 	rt = XFS_IS_REALTIME_INODE(ip);
807 	extsz = xfs_get_extsz_hint(ip);
808 
809 	count = len;
810 	imapp = &imaps[0];
811 	nimaps = 1;
812 	startoffset_fsb	= XFS_B_TO_FSBT(mp, offset);
813 	endoffset_fsb = XFS_B_TO_FSB(mp, offset + count);
814 	allocatesize_fsb = endoffset_fsb - startoffset_fsb;
815 
816 	/*
817 	 * Allocate file space until done or until there is an error
818 	 */
819 	while (allocatesize_fsb && !error) {
820 		xfs_fileoff_t	s, e;
821 		unsigned int	dblocks, rblocks, resblks;
822 
823 		/*
824 		 * Determine space reservations for data/realtime.
825 		 */
826 		if (unlikely(extsz)) {
827 			s = startoffset_fsb;
828 			do_div(s, extsz);
829 			s *= extsz;
830 			e = startoffset_fsb + allocatesize_fsb;
831 			div_u64_rem(startoffset_fsb, extsz, &temp);
832 			if (temp)
833 				e += temp;
834 			div_u64_rem(e, extsz, &temp);
835 			if (temp)
836 				e += extsz - temp;
837 		} else {
838 			s = 0;
839 			e = allocatesize_fsb;
840 		}
841 
842 		/*
843 		 * The transaction reservation is limited to a 32-bit block
844 		 * count, hence we need to limit the number of blocks we are
845 		 * trying to reserve to avoid an overflow. We can't allocate
846 		 * more than @nimaps extents, and an extent is limited on disk
847 		 * to XFS_BMBT_MAX_EXTLEN (21 bits), so use that to enforce the
848 		 * limit.
849 		 */
850 		resblks = min_t(xfs_fileoff_t, (e - s),
851 				(XFS_MAX_BMBT_EXTLEN * nimaps));
852 		if (unlikely(rt)) {
853 			dblocks = XFS_DIOSTRAT_SPACE_RES(mp, 0);
854 			rblocks = resblks;
855 		} else {
856 			dblocks = XFS_DIOSTRAT_SPACE_RES(mp, resblks);
857 			rblocks = 0;
858 		}
859 
860 		error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write,
861 				dblocks, rblocks, false, &tp);
862 		if (error)
863 			break;
864 
865 		error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK,
866 				XFS_IEXT_ADD_NOSPLIT_CNT);
867 		if (error == -EFBIG)
868 			error = xfs_iext_count_upgrade(tp, ip,
869 					XFS_IEXT_ADD_NOSPLIT_CNT);
870 		if (error)
871 			goto error;
872 
873 		error = xfs_bmapi_write(tp, ip, startoffset_fsb,
874 				allocatesize_fsb, XFS_BMAPI_PREALLOC, 0, imapp,
875 				&nimaps);
876 		if (error)
877 			goto error;
878 
879 		ip->i_diflags |= XFS_DIFLAG_PREALLOC;
880 		xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
881 
882 		error = xfs_trans_commit(tp);
883 		xfs_iunlock(ip, XFS_ILOCK_EXCL);
884 		if (error)
885 			break;
886 
887 		allocated_fsb = imapp->br_blockcount;
888 
889 		if (nimaps == 0) {
890 			error = -ENOSPC;
891 			break;
892 		}
893 
894 		startoffset_fsb += allocated_fsb;
895 		allocatesize_fsb -= allocated_fsb;
896 	}
897 
898 	return error;
899 
900 error:
901 	xfs_trans_cancel(tp);
902 	xfs_iunlock(ip, XFS_ILOCK_EXCL);
903 	return error;
904 }
905 
906 static int
907 xfs_unmap_extent(
908 	struct xfs_inode	*ip,
909 	xfs_fileoff_t		startoffset_fsb,
910 	xfs_filblks_t		len_fsb,
911 	int			*done)
912 {
913 	struct xfs_mount	*mp = ip->i_mount;
914 	struct xfs_trans	*tp;
915 	uint			resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0);
916 	int			error;
917 
918 	error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write, resblks, 0,
919 			false, &tp);
920 	if (error)
921 		return error;
922 
923 	error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK,
924 			XFS_IEXT_PUNCH_HOLE_CNT);
925 	if (error == -EFBIG)
926 		error = xfs_iext_count_upgrade(tp, ip, XFS_IEXT_PUNCH_HOLE_CNT);
927 	if (error)
928 		goto out_trans_cancel;
929 
930 	error = xfs_bunmapi(tp, ip, startoffset_fsb, len_fsb, 0, 2, done);
931 	if (error)
932 		goto out_trans_cancel;
933 
934 	error = xfs_trans_commit(tp);
935 out_unlock:
936 	xfs_iunlock(ip, XFS_ILOCK_EXCL);
937 	return error;
938 
939 out_trans_cancel:
940 	xfs_trans_cancel(tp);
941 	goto out_unlock;
942 }
943 
944 /* Caller must first wait for the completion of any pending DIOs if required. */
945 int
946 xfs_flush_unmap_range(
947 	struct xfs_inode	*ip,
948 	xfs_off_t		offset,
949 	xfs_off_t		len)
950 {
951 	struct xfs_mount	*mp = ip->i_mount;
952 	struct inode		*inode = VFS_I(ip);
953 	xfs_off_t		rounding, start, end;
954 	int			error;
955 
956 	rounding = max_t(xfs_off_t, mp->m_sb.sb_blocksize, PAGE_SIZE);
957 	start = round_down(offset, rounding);
958 	end = round_up(offset + len, rounding) - 1;
959 
960 	error = filemap_write_and_wait_range(inode->i_mapping, start, end);
961 	if (error)
962 		return error;
963 	truncate_pagecache_range(inode, start, end);
964 	return 0;
965 }
966 
967 int
968 xfs_free_file_space(
969 	struct xfs_inode	*ip,
970 	xfs_off_t		offset,
971 	xfs_off_t		len)
972 {
973 	struct xfs_mount	*mp = ip->i_mount;
974 	xfs_fileoff_t		startoffset_fsb;
975 	xfs_fileoff_t		endoffset_fsb;
976 	int			done = 0, error;
977 
978 	trace_xfs_free_file_space(ip);
979 
980 	error = xfs_qm_dqattach(ip);
981 	if (error)
982 		return error;
983 
984 	if (len <= 0)	/* if nothing being freed */
985 		return 0;
986 
987 	startoffset_fsb = XFS_B_TO_FSB(mp, offset);
988 	endoffset_fsb = XFS_B_TO_FSBT(mp, offset + len);
989 
990 	/* We can only free complete realtime extents. */
991 	if (XFS_IS_REALTIME_INODE(ip) && mp->m_sb.sb_rextsize > 1) {
992 		startoffset_fsb = roundup_64(startoffset_fsb,
993 					     mp->m_sb.sb_rextsize);
994 		endoffset_fsb = rounddown_64(endoffset_fsb,
995 					     mp->m_sb.sb_rextsize);
996 	}
997 
998 	/*
999 	 * Need to zero the stuff we're not freeing, on disk.
1000 	 */
1001 	if (endoffset_fsb > startoffset_fsb) {
1002 		while (!done) {
1003 			error = xfs_unmap_extent(ip, startoffset_fsb,
1004 					endoffset_fsb - startoffset_fsb, &done);
1005 			if (error)
1006 				return error;
1007 		}
1008 	}
1009 
1010 	/*
1011 	 * Now that we've unmap all full blocks we'll have to zero out any
1012 	 * partial block at the beginning and/or end.  xfs_zero_range is smart
1013 	 * enough to skip any holes, including those we just created, but we
1014 	 * must take care not to zero beyond EOF and enlarge i_size.
1015 	 */
1016 	if (offset >= XFS_ISIZE(ip))
1017 		return 0;
1018 	if (offset + len > XFS_ISIZE(ip))
1019 		len = XFS_ISIZE(ip) - offset;
1020 	error = xfs_zero_range(ip, offset, len, NULL);
1021 	if (error)
1022 		return error;
1023 
1024 	/*
1025 	 * If we zeroed right up to EOF and EOF straddles a page boundary we
1026 	 * must make sure that the post-EOF area is also zeroed because the
1027 	 * page could be mmap'd and xfs_zero_range doesn't do that for us.
1028 	 * Writeback of the eof page will do this, albeit clumsily.
1029 	 */
1030 	if (offset + len >= XFS_ISIZE(ip) && offset_in_page(offset + len) > 0) {
1031 		error = filemap_write_and_wait_range(VFS_I(ip)->i_mapping,
1032 				round_down(offset + len, PAGE_SIZE), LLONG_MAX);
1033 	}
1034 
1035 	return error;
1036 }
1037 
1038 static int
1039 xfs_prepare_shift(
1040 	struct xfs_inode	*ip,
1041 	loff_t			offset)
1042 {
1043 	struct xfs_mount	*mp = ip->i_mount;
1044 	int			error;
1045 
1046 	/*
1047 	 * Trim eofblocks to avoid shifting uninitialized post-eof preallocation
1048 	 * into the accessible region of the file.
1049 	 */
1050 	if (xfs_can_free_eofblocks(ip, true)) {
1051 		error = xfs_free_eofblocks(ip);
1052 		if (error)
1053 			return error;
1054 	}
1055 
1056 	/*
1057 	 * Shift operations must stabilize the start block offset boundary along
1058 	 * with the full range of the operation. If we don't, a COW writeback
1059 	 * completion could race with an insert, front merge with the start
1060 	 * extent (after split) during the shift and corrupt the file. Start
1061 	 * with the block just prior to the start to stabilize the boundary.
1062 	 */
1063 	offset = round_down(offset, mp->m_sb.sb_blocksize);
1064 	if (offset)
1065 		offset -= mp->m_sb.sb_blocksize;
1066 
1067 	/*
1068 	 * Writeback and invalidate cache for the remainder of the file as we're
1069 	 * about to shift down every extent from offset to EOF.
1070 	 */
1071 	error = xfs_flush_unmap_range(ip, offset, XFS_ISIZE(ip));
1072 	if (error)
1073 		return error;
1074 
1075 	/*
1076 	 * Clean out anything hanging around in the cow fork now that
1077 	 * we've flushed all the dirty data out to disk to avoid having
1078 	 * CoW extents at the wrong offsets.
1079 	 */
1080 	if (xfs_inode_has_cow_data(ip)) {
1081 		error = xfs_reflink_cancel_cow_range(ip, offset, NULLFILEOFF,
1082 				true);
1083 		if (error)
1084 			return error;
1085 	}
1086 
1087 	return 0;
1088 }
1089 
1090 /*
1091  * xfs_collapse_file_space()
1092  *	This routine frees disk space and shift extent for the given file.
1093  *	The first thing we do is to free data blocks in the specified range
1094  *	by calling xfs_free_file_space(). It would also sync dirty data
1095  *	and invalidate page cache over the region on which collapse range
1096  *	is working. And Shift extent records to the left to cover a hole.
1097  * RETURNS:
1098  *	0 on success
1099  *	errno on error
1100  *
1101  */
1102 int
1103 xfs_collapse_file_space(
1104 	struct xfs_inode	*ip,
1105 	xfs_off_t		offset,
1106 	xfs_off_t		len)
1107 {
1108 	struct xfs_mount	*mp = ip->i_mount;
1109 	struct xfs_trans	*tp;
1110 	int			error;
1111 	xfs_fileoff_t		next_fsb = XFS_B_TO_FSB(mp, offset + len);
1112 	xfs_fileoff_t		shift_fsb = XFS_B_TO_FSB(mp, len);
1113 	bool			done = false;
1114 
1115 	ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL));
1116 	ASSERT(xfs_isilocked(ip, XFS_MMAPLOCK_EXCL));
1117 
1118 	trace_xfs_collapse_file_space(ip);
1119 
1120 	error = xfs_free_file_space(ip, offset, len);
1121 	if (error)
1122 		return error;
1123 
1124 	error = xfs_prepare_shift(ip, offset);
1125 	if (error)
1126 		return error;
1127 
1128 	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, 0, 0, 0, &tp);
1129 	if (error)
1130 		return error;
1131 
1132 	xfs_ilock(ip, XFS_ILOCK_EXCL);
1133 	xfs_trans_ijoin(tp, ip, 0);
1134 
1135 	while (!done) {
1136 		error = xfs_bmap_collapse_extents(tp, ip, &next_fsb, shift_fsb,
1137 				&done);
1138 		if (error)
1139 			goto out_trans_cancel;
1140 		if (done)
1141 			break;
1142 
1143 		/* finish any deferred frees and roll the transaction */
1144 		error = xfs_defer_finish(&tp);
1145 		if (error)
1146 			goto out_trans_cancel;
1147 	}
1148 
1149 	error = xfs_trans_commit(tp);
1150 	xfs_iunlock(ip, XFS_ILOCK_EXCL);
1151 	return error;
1152 
1153 out_trans_cancel:
1154 	xfs_trans_cancel(tp);
1155 	xfs_iunlock(ip, XFS_ILOCK_EXCL);
1156 	return error;
1157 }
1158 
1159 /*
1160  * xfs_insert_file_space()
1161  *	This routine create hole space by shifting extents for the given file.
1162  *	The first thing we do is to sync dirty data and invalidate page cache
1163  *	over the region on which insert range is working. And split an extent
1164  *	to two extents at given offset by calling xfs_bmap_split_extent.
1165  *	And shift all extent records which are laying between [offset,
1166  *	last allocated extent] to the right to reserve hole range.
1167  * RETURNS:
1168  *	0 on success
1169  *	errno on error
1170  */
1171 int
1172 xfs_insert_file_space(
1173 	struct xfs_inode	*ip,
1174 	loff_t			offset,
1175 	loff_t			len)
1176 {
1177 	struct xfs_mount	*mp = ip->i_mount;
1178 	struct xfs_trans	*tp;
1179 	int			error;
1180 	xfs_fileoff_t		stop_fsb = XFS_B_TO_FSB(mp, offset);
1181 	xfs_fileoff_t		next_fsb = NULLFSBLOCK;
1182 	xfs_fileoff_t		shift_fsb = XFS_B_TO_FSB(mp, len);
1183 	bool			done = false;
1184 
1185 	ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL));
1186 	ASSERT(xfs_isilocked(ip, XFS_MMAPLOCK_EXCL));
1187 
1188 	trace_xfs_insert_file_space(ip);
1189 
1190 	error = xfs_bmap_can_insert_extents(ip, stop_fsb, shift_fsb);
1191 	if (error)
1192 		return error;
1193 
1194 	error = xfs_prepare_shift(ip, offset);
1195 	if (error)
1196 		return error;
1197 
1198 	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write,
1199 			XFS_DIOSTRAT_SPACE_RES(mp, 0), 0, 0, &tp);
1200 	if (error)
1201 		return error;
1202 
1203 	xfs_ilock(ip, XFS_ILOCK_EXCL);
1204 	xfs_trans_ijoin(tp, ip, 0);
1205 
1206 	error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK,
1207 			XFS_IEXT_PUNCH_HOLE_CNT);
1208 	if (error == -EFBIG)
1209 		error = xfs_iext_count_upgrade(tp, ip, XFS_IEXT_PUNCH_HOLE_CNT);
1210 	if (error)
1211 		goto out_trans_cancel;
1212 
1213 	/*
1214 	 * The extent shifting code works on extent granularity. So, if stop_fsb
1215 	 * is not the starting block of extent, we need to split the extent at
1216 	 * stop_fsb.
1217 	 */
1218 	error = xfs_bmap_split_extent(tp, ip, stop_fsb);
1219 	if (error)
1220 		goto out_trans_cancel;
1221 
1222 	do {
1223 		error = xfs_defer_finish(&tp);
1224 		if (error)
1225 			goto out_trans_cancel;
1226 
1227 		error = xfs_bmap_insert_extents(tp, ip, &next_fsb, shift_fsb,
1228 				&done, stop_fsb);
1229 		if (error)
1230 			goto out_trans_cancel;
1231 	} while (!done);
1232 
1233 	error = xfs_trans_commit(tp);
1234 	xfs_iunlock(ip, XFS_ILOCK_EXCL);
1235 	return error;
1236 
1237 out_trans_cancel:
1238 	xfs_trans_cancel(tp);
1239 	xfs_iunlock(ip, XFS_ILOCK_EXCL);
1240 	return error;
1241 }
1242 
1243 /*
1244  * We need to check that the format of the data fork in the temporary inode is
1245  * valid for the target inode before doing the swap. This is not a problem with
1246  * attr1 because of the fixed fork offset, but attr2 has a dynamically sized
1247  * data fork depending on the space the attribute fork is taking so we can get
1248  * invalid formats on the target inode.
1249  *
1250  * E.g. target has space for 7 extents in extent format, temp inode only has
1251  * space for 6.  If we defragment down to 7 extents, then the tmp format is a
1252  * btree, but when swapped it needs to be in extent format. Hence we can't just
1253  * blindly swap data forks on attr2 filesystems.
1254  *
1255  * Note that we check the swap in both directions so that we don't end up with
1256  * a corrupt temporary inode, either.
1257  *
1258  * Note that fixing the way xfs_fsr sets up the attribute fork in the source
1259  * inode will prevent this situation from occurring, so all we do here is
1260  * reject and log the attempt. basically we are putting the responsibility on
1261  * userspace to get this right.
1262  */
1263 static int
1264 xfs_swap_extents_check_format(
1265 	struct xfs_inode	*ip,	/* target inode */
1266 	struct xfs_inode	*tip)	/* tmp inode */
1267 {
1268 	struct xfs_ifork	*ifp = &ip->i_df;
1269 	struct xfs_ifork	*tifp = &tip->i_df;
1270 
1271 	/* User/group/project quota ids must match if quotas are enforced. */
1272 	if (XFS_IS_QUOTA_ON(ip->i_mount) &&
1273 	    (!uid_eq(VFS_I(ip)->i_uid, VFS_I(tip)->i_uid) ||
1274 	     !gid_eq(VFS_I(ip)->i_gid, VFS_I(tip)->i_gid) ||
1275 	     ip->i_projid != tip->i_projid))
1276 		return -EINVAL;
1277 
1278 	/* Should never get a local format */
1279 	if (ifp->if_format == XFS_DINODE_FMT_LOCAL ||
1280 	    tifp->if_format == XFS_DINODE_FMT_LOCAL)
1281 		return -EINVAL;
1282 
1283 	/*
1284 	 * if the target inode has less extents that then temporary inode then
1285 	 * why did userspace call us?
1286 	 */
1287 	if (ifp->if_nextents < tifp->if_nextents)
1288 		return -EINVAL;
1289 
1290 	/*
1291 	 * If we have to use the (expensive) rmap swap method, we can
1292 	 * handle any number of extents and any format.
1293 	 */
1294 	if (xfs_has_rmapbt(ip->i_mount))
1295 		return 0;
1296 
1297 	/*
1298 	 * if the target inode is in extent form and the temp inode is in btree
1299 	 * form then we will end up with the target inode in the wrong format
1300 	 * as we already know there are less extents in the temp inode.
1301 	 */
1302 	if (ifp->if_format == XFS_DINODE_FMT_EXTENTS &&
1303 	    tifp->if_format == XFS_DINODE_FMT_BTREE)
1304 		return -EINVAL;
1305 
1306 	/* Check temp in extent form to max in target */
1307 	if (tifp->if_format == XFS_DINODE_FMT_EXTENTS &&
1308 	    tifp->if_nextents > XFS_IFORK_MAXEXT(ip, XFS_DATA_FORK))
1309 		return -EINVAL;
1310 
1311 	/* Check target in extent form to max in temp */
1312 	if (ifp->if_format == XFS_DINODE_FMT_EXTENTS &&
1313 	    ifp->if_nextents > XFS_IFORK_MAXEXT(tip, XFS_DATA_FORK))
1314 		return -EINVAL;
1315 
1316 	/*
1317 	 * If we are in a btree format, check that the temp root block will fit
1318 	 * in the target and that it has enough extents to be in btree format
1319 	 * in the target.
1320 	 *
1321 	 * Note that we have to be careful to allow btree->extent conversions
1322 	 * (a common defrag case) which will occur when the temp inode is in
1323 	 * extent format...
1324 	 */
1325 	if (tifp->if_format == XFS_DINODE_FMT_BTREE) {
1326 		if (xfs_inode_has_attr_fork(ip) &&
1327 		    XFS_BMAP_BMDR_SPACE(tifp->if_broot) > xfs_inode_fork_boff(ip))
1328 			return -EINVAL;
1329 		if (tifp->if_nextents <= XFS_IFORK_MAXEXT(ip, XFS_DATA_FORK))
1330 			return -EINVAL;
1331 	}
1332 
1333 	/* Reciprocal target->temp btree format checks */
1334 	if (ifp->if_format == XFS_DINODE_FMT_BTREE) {
1335 		if (xfs_inode_has_attr_fork(tip) &&
1336 		    XFS_BMAP_BMDR_SPACE(ip->i_df.if_broot) > xfs_inode_fork_boff(tip))
1337 			return -EINVAL;
1338 		if (ifp->if_nextents <= XFS_IFORK_MAXEXT(tip, XFS_DATA_FORK))
1339 			return -EINVAL;
1340 	}
1341 
1342 	return 0;
1343 }
1344 
1345 static int
1346 xfs_swap_extent_flush(
1347 	struct xfs_inode	*ip)
1348 {
1349 	int	error;
1350 
1351 	error = filemap_write_and_wait(VFS_I(ip)->i_mapping);
1352 	if (error)
1353 		return error;
1354 	truncate_pagecache_range(VFS_I(ip), 0, -1);
1355 
1356 	/* Verify O_DIRECT for ftmp */
1357 	if (VFS_I(ip)->i_mapping->nrpages)
1358 		return -EINVAL;
1359 	return 0;
1360 }
1361 
1362 /*
1363  * Move extents from one file to another, when rmap is enabled.
1364  */
1365 STATIC int
1366 xfs_swap_extent_rmap(
1367 	struct xfs_trans		**tpp,
1368 	struct xfs_inode		*ip,
1369 	struct xfs_inode		*tip)
1370 {
1371 	struct xfs_trans		*tp = *tpp;
1372 	struct xfs_bmbt_irec		irec;
1373 	struct xfs_bmbt_irec		uirec;
1374 	struct xfs_bmbt_irec		tirec;
1375 	xfs_fileoff_t			offset_fsb;
1376 	xfs_fileoff_t			end_fsb;
1377 	xfs_filblks_t			count_fsb;
1378 	int				error;
1379 	xfs_filblks_t			ilen;
1380 	xfs_filblks_t			rlen;
1381 	int				nimaps;
1382 	uint64_t			tip_flags2;
1383 
1384 	/*
1385 	 * If the source file has shared blocks, we must flag the donor
1386 	 * file as having shared blocks so that we get the shared-block
1387 	 * rmap functions when we go to fix up the rmaps.  The flags
1388 	 * will be switch for reals later.
1389 	 */
1390 	tip_flags2 = tip->i_diflags2;
1391 	if (ip->i_diflags2 & XFS_DIFLAG2_REFLINK)
1392 		tip->i_diflags2 |= XFS_DIFLAG2_REFLINK;
1393 
1394 	offset_fsb = 0;
1395 	end_fsb = XFS_B_TO_FSB(ip->i_mount, i_size_read(VFS_I(ip)));
1396 	count_fsb = (xfs_filblks_t)(end_fsb - offset_fsb);
1397 
1398 	while (count_fsb) {
1399 		/* Read extent from the donor file */
1400 		nimaps = 1;
1401 		error = xfs_bmapi_read(tip, offset_fsb, count_fsb, &tirec,
1402 				&nimaps, 0);
1403 		if (error)
1404 			goto out;
1405 		ASSERT(nimaps == 1);
1406 		ASSERT(tirec.br_startblock != DELAYSTARTBLOCK);
1407 
1408 		trace_xfs_swap_extent_rmap_remap(tip, &tirec);
1409 		ilen = tirec.br_blockcount;
1410 
1411 		/* Unmap the old blocks in the source file. */
1412 		while (tirec.br_blockcount) {
1413 			ASSERT(tp->t_highest_agno == NULLAGNUMBER);
1414 			trace_xfs_swap_extent_rmap_remap_piece(tip, &tirec);
1415 
1416 			/* Read extent from the source file */
1417 			nimaps = 1;
1418 			error = xfs_bmapi_read(ip, tirec.br_startoff,
1419 					tirec.br_blockcount, &irec,
1420 					&nimaps, 0);
1421 			if (error)
1422 				goto out;
1423 			ASSERT(nimaps == 1);
1424 			ASSERT(tirec.br_startoff == irec.br_startoff);
1425 			trace_xfs_swap_extent_rmap_remap_piece(ip, &irec);
1426 
1427 			/* Trim the extent. */
1428 			uirec = tirec;
1429 			uirec.br_blockcount = rlen = min_t(xfs_filblks_t,
1430 					tirec.br_blockcount,
1431 					irec.br_blockcount);
1432 			trace_xfs_swap_extent_rmap_remap_piece(tip, &uirec);
1433 
1434 			if (xfs_bmap_is_real_extent(&uirec)) {
1435 				error = xfs_iext_count_may_overflow(ip,
1436 						XFS_DATA_FORK,
1437 						XFS_IEXT_SWAP_RMAP_CNT);
1438 				if (error == -EFBIG)
1439 					error = xfs_iext_count_upgrade(tp, ip,
1440 							XFS_IEXT_SWAP_RMAP_CNT);
1441 				if (error)
1442 					goto out;
1443 			}
1444 
1445 			if (xfs_bmap_is_real_extent(&irec)) {
1446 				error = xfs_iext_count_may_overflow(tip,
1447 						XFS_DATA_FORK,
1448 						XFS_IEXT_SWAP_RMAP_CNT);
1449 				if (error == -EFBIG)
1450 					error = xfs_iext_count_upgrade(tp, ip,
1451 							XFS_IEXT_SWAP_RMAP_CNT);
1452 				if (error)
1453 					goto out;
1454 			}
1455 
1456 			/* Remove the mapping from the donor file. */
1457 			xfs_bmap_unmap_extent(tp, tip, &uirec);
1458 
1459 			/* Remove the mapping from the source file. */
1460 			xfs_bmap_unmap_extent(tp, ip, &irec);
1461 
1462 			/* Map the donor file's blocks into the source file. */
1463 			xfs_bmap_map_extent(tp, ip, &uirec);
1464 
1465 			/* Map the source file's blocks into the donor file. */
1466 			xfs_bmap_map_extent(tp, tip, &irec);
1467 
1468 			error = xfs_defer_finish(tpp);
1469 			tp = *tpp;
1470 			if (error)
1471 				goto out;
1472 
1473 			tirec.br_startoff += rlen;
1474 			if (tirec.br_startblock != HOLESTARTBLOCK &&
1475 			    tirec.br_startblock != DELAYSTARTBLOCK)
1476 				tirec.br_startblock += rlen;
1477 			tirec.br_blockcount -= rlen;
1478 		}
1479 
1480 		/* Roll on... */
1481 		count_fsb -= ilen;
1482 		offset_fsb += ilen;
1483 	}
1484 
1485 	tip->i_diflags2 = tip_flags2;
1486 	return 0;
1487 
1488 out:
1489 	trace_xfs_swap_extent_rmap_error(ip, error, _RET_IP_);
1490 	tip->i_diflags2 = tip_flags2;
1491 	return error;
1492 }
1493 
1494 /* Swap the extents of two files by swapping data forks. */
1495 STATIC int
1496 xfs_swap_extent_forks(
1497 	struct xfs_trans	*tp,
1498 	struct xfs_inode	*ip,
1499 	struct xfs_inode	*tip,
1500 	int			*src_log_flags,
1501 	int			*target_log_flags)
1502 {
1503 	xfs_filblks_t		aforkblks = 0;
1504 	xfs_filblks_t		taforkblks = 0;
1505 	xfs_extnum_t		junk;
1506 	uint64_t		tmp;
1507 	int			error;
1508 
1509 	/*
1510 	 * Count the number of extended attribute blocks
1511 	 */
1512 	if (xfs_inode_has_attr_fork(ip) && ip->i_af.if_nextents > 0 &&
1513 	    ip->i_af.if_format != XFS_DINODE_FMT_LOCAL) {
1514 		error = xfs_bmap_count_blocks(tp, ip, XFS_ATTR_FORK, &junk,
1515 				&aforkblks);
1516 		if (error)
1517 			return error;
1518 	}
1519 	if (xfs_inode_has_attr_fork(tip) && tip->i_af.if_nextents > 0 &&
1520 	    tip->i_af.if_format != XFS_DINODE_FMT_LOCAL) {
1521 		error = xfs_bmap_count_blocks(tp, tip, XFS_ATTR_FORK, &junk,
1522 				&taforkblks);
1523 		if (error)
1524 			return error;
1525 	}
1526 
1527 	/*
1528 	 * Btree format (v3) inodes have the inode number stamped in the bmbt
1529 	 * block headers. We can't start changing the bmbt blocks until the
1530 	 * inode owner change is logged so recovery does the right thing in the
1531 	 * event of a crash. Set the owner change log flags now and leave the
1532 	 * bmbt scan as the last step.
1533 	 */
1534 	if (xfs_has_v3inodes(ip->i_mount)) {
1535 		if (ip->i_df.if_format == XFS_DINODE_FMT_BTREE)
1536 			(*target_log_flags) |= XFS_ILOG_DOWNER;
1537 		if (tip->i_df.if_format == XFS_DINODE_FMT_BTREE)
1538 			(*src_log_flags) |= XFS_ILOG_DOWNER;
1539 	}
1540 
1541 	/*
1542 	 * Swap the data forks of the inodes
1543 	 */
1544 	swap(ip->i_df, tip->i_df);
1545 
1546 	/*
1547 	 * Fix the on-disk inode values
1548 	 */
1549 	tmp = (uint64_t)ip->i_nblocks;
1550 	ip->i_nblocks = tip->i_nblocks - taforkblks + aforkblks;
1551 	tip->i_nblocks = tmp + taforkblks - aforkblks;
1552 
1553 	/*
1554 	 * The extents in the source inode could still contain speculative
1555 	 * preallocation beyond EOF (e.g. the file is open but not modified
1556 	 * while defrag is in progress). In that case, we need to copy over the
1557 	 * number of delalloc blocks the data fork in the source inode is
1558 	 * tracking beyond EOF so that when the fork is truncated away when the
1559 	 * temporary inode is unlinked we don't underrun the i_delayed_blks
1560 	 * counter on that inode.
1561 	 */
1562 	ASSERT(tip->i_delayed_blks == 0);
1563 	tip->i_delayed_blks = ip->i_delayed_blks;
1564 	ip->i_delayed_blks = 0;
1565 
1566 	switch (ip->i_df.if_format) {
1567 	case XFS_DINODE_FMT_EXTENTS:
1568 		(*src_log_flags) |= XFS_ILOG_DEXT;
1569 		break;
1570 	case XFS_DINODE_FMT_BTREE:
1571 		ASSERT(!xfs_has_v3inodes(ip->i_mount) ||
1572 		       (*src_log_flags & XFS_ILOG_DOWNER));
1573 		(*src_log_flags) |= XFS_ILOG_DBROOT;
1574 		break;
1575 	}
1576 
1577 	switch (tip->i_df.if_format) {
1578 	case XFS_DINODE_FMT_EXTENTS:
1579 		(*target_log_flags) |= XFS_ILOG_DEXT;
1580 		break;
1581 	case XFS_DINODE_FMT_BTREE:
1582 		(*target_log_flags) |= XFS_ILOG_DBROOT;
1583 		ASSERT(!xfs_has_v3inodes(ip->i_mount) ||
1584 		       (*target_log_flags & XFS_ILOG_DOWNER));
1585 		break;
1586 	}
1587 
1588 	return 0;
1589 }
1590 
1591 /*
1592  * Fix up the owners of the bmbt blocks to refer to the current inode. The
1593  * change owner scan attempts to order all modified buffers in the current
1594  * transaction. In the event of ordered buffer failure, the offending buffer is
1595  * physically logged as a fallback and the scan returns -EAGAIN. We must roll
1596  * the transaction in this case to replenish the fallback log reservation and
1597  * restart the scan. This process repeats until the scan completes.
1598  */
1599 static int
1600 xfs_swap_change_owner(
1601 	struct xfs_trans	**tpp,
1602 	struct xfs_inode	*ip,
1603 	struct xfs_inode	*tmpip)
1604 {
1605 	int			error;
1606 	struct xfs_trans	*tp = *tpp;
1607 
1608 	do {
1609 		error = xfs_bmbt_change_owner(tp, ip, XFS_DATA_FORK, ip->i_ino,
1610 					      NULL);
1611 		/* success or fatal error */
1612 		if (error != -EAGAIN)
1613 			break;
1614 
1615 		error = xfs_trans_roll(tpp);
1616 		if (error)
1617 			break;
1618 		tp = *tpp;
1619 
1620 		/*
1621 		 * Redirty both inodes so they can relog and keep the log tail
1622 		 * moving forward.
1623 		 */
1624 		xfs_trans_ijoin(tp, ip, 0);
1625 		xfs_trans_ijoin(tp, tmpip, 0);
1626 		xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
1627 		xfs_trans_log_inode(tp, tmpip, XFS_ILOG_CORE);
1628 	} while (true);
1629 
1630 	return error;
1631 }
1632 
1633 int
1634 xfs_swap_extents(
1635 	struct xfs_inode	*ip,	/* target inode */
1636 	struct xfs_inode	*tip,	/* tmp inode */
1637 	struct xfs_swapext	*sxp)
1638 {
1639 	struct xfs_mount	*mp = ip->i_mount;
1640 	struct xfs_trans	*tp;
1641 	struct xfs_bstat	*sbp = &sxp->sx_stat;
1642 	int			src_log_flags, target_log_flags;
1643 	int			error = 0;
1644 	uint64_t		f;
1645 	int			resblks = 0;
1646 	unsigned int		flags = 0;
1647 	struct timespec64	ctime;
1648 
1649 	/*
1650 	 * Lock the inodes against other IO, page faults and truncate to
1651 	 * begin with.  Then we can ensure the inodes are flushed and have no
1652 	 * page cache safely. Once we have done this we can take the ilocks and
1653 	 * do the rest of the checks.
1654 	 */
1655 	lock_two_nondirectories(VFS_I(ip), VFS_I(tip));
1656 	filemap_invalidate_lock_two(VFS_I(ip)->i_mapping,
1657 				    VFS_I(tip)->i_mapping);
1658 
1659 	/* Verify that both files have the same format */
1660 	if ((VFS_I(ip)->i_mode & S_IFMT) != (VFS_I(tip)->i_mode & S_IFMT)) {
1661 		error = -EINVAL;
1662 		goto out_unlock;
1663 	}
1664 
1665 	/* Verify both files are either real-time or non-realtime */
1666 	if (XFS_IS_REALTIME_INODE(ip) != XFS_IS_REALTIME_INODE(tip)) {
1667 		error = -EINVAL;
1668 		goto out_unlock;
1669 	}
1670 
1671 	error = xfs_qm_dqattach(ip);
1672 	if (error)
1673 		goto out_unlock;
1674 
1675 	error = xfs_qm_dqattach(tip);
1676 	if (error)
1677 		goto out_unlock;
1678 
1679 	error = xfs_swap_extent_flush(ip);
1680 	if (error)
1681 		goto out_unlock;
1682 	error = xfs_swap_extent_flush(tip);
1683 	if (error)
1684 		goto out_unlock;
1685 
1686 	if (xfs_inode_has_cow_data(tip)) {
1687 		error = xfs_reflink_cancel_cow_range(tip, 0, NULLFILEOFF, true);
1688 		if (error)
1689 			goto out_unlock;
1690 	}
1691 
1692 	/*
1693 	 * Extent "swapping" with rmap requires a permanent reservation and
1694 	 * a block reservation because it's really just a remap operation
1695 	 * performed with log redo items!
1696 	 */
1697 	if (xfs_has_rmapbt(mp)) {
1698 		int		w = XFS_DATA_FORK;
1699 		uint32_t	ipnext = ip->i_df.if_nextents;
1700 		uint32_t	tipnext	= tip->i_df.if_nextents;
1701 
1702 		/*
1703 		 * Conceptually this shouldn't affect the shape of either bmbt,
1704 		 * but since we atomically move extents one by one, we reserve
1705 		 * enough space to rebuild both trees.
1706 		 */
1707 		resblks = XFS_SWAP_RMAP_SPACE_RES(mp, ipnext, w);
1708 		resblks +=  XFS_SWAP_RMAP_SPACE_RES(mp, tipnext, w);
1709 
1710 		/*
1711 		 * If either inode straddles a bmapbt block allocation boundary,
1712 		 * the rmapbt algorithm triggers repeated allocs and frees as
1713 		 * extents are remapped. This can exhaust the block reservation
1714 		 * prematurely and cause shutdown. Return freed blocks to the
1715 		 * transaction reservation to counter this behavior.
1716 		 */
1717 		flags |= XFS_TRANS_RES_FDBLKS;
1718 	}
1719 	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, 0, flags,
1720 				&tp);
1721 	if (error)
1722 		goto out_unlock;
1723 
1724 	/*
1725 	 * Lock and join the inodes to the tansaction so that transaction commit
1726 	 * or cancel will unlock the inodes from this point onwards.
1727 	 */
1728 	xfs_lock_two_inodes(ip, XFS_ILOCK_EXCL, tip, XFS_ILOCK_EXCL);
1729 	xfs_trans_ijoin(tp, ip, 0);
1730 	xfs_trans_ijoin(tp, tip, 0);
1731 
1732 
1733 	/* Verify all data are being swapped */
1734 	if (sxp->sx_offset != 0 ||
1735 	    sxp->sx_length != ip->i_disk_size ||
1736 	    sxp->sx_length != tip->i_disk_size) {
1737 		error = -EFAULT;
1738 		goto out_trans_cancel;
1739 	}
1740 
1741 	trace_xfs_swap_extent_before(ip, 0);
1742 	trace_xfs_swap_extent_before(tip, 1);
1743 
1744 	/* check inode formats now that data is flushed */
1745 	error = xfs_swap_extents_check_format(ip, tip);
1746 	if (error) {
1747 		xfs_notice(mp,
1748 		    "%s: inode 0x%llx format is incompatible for exchanging.",
1749 				__func__, ip->i_ino);
1750 		goto out_trans_cancel;
1751 	}
1752 
1753 	/*
1754 	 * Compare the current change & modify times with that
1755 	 * passed in.  If they differ, we abort this swap.
1756 	 * This is the mechanism used to ensure the calling
1757 	 * process that the file was not changed out from
1758 	 * under it.
1759 	 */
1760 	ctime = inode_get_ctime(VFS_I(ip));
1761 	if ((sbp->bs_ctime.tv_sec != ctime.tv_sec) ||
1762 	    (sbp->bs_ctime.tv_nsec != ctime.tv_nsec) ||
1763 	    (sbp->bs_mtime.tv_sec != VFS_I(ip)->i_mtime.tv_sec) ||
1764 	    (sbp->bs_mtime.tv_nsec != VFS_I(ip)->i_mtime.tv_nsec)) {
1765 		error = -EBUSY;
1766 		goto out_trans_cancel;
1767 	}
1768 
1769 	/*
1770 	 * Note the trickiness in setting the log flags - we set the owner log
1771 	 * flag on the opposite inode (i.e. the inode we are setting the new
1772 	 * owner to be) because once we swap the forks and log that, log
1773 	 * recovery is going to see the fork as owned by the swapped inode,
1774 	 * not the pre-swapped inodes.
1775 	 */
1776 	src_log_flags = XFS_ILOG_CORE;
1777 	target_log_flags = XFS_ILOG_CORE;
1778 
1779 	if (xfs_has_rmapbt(mp))
1780 		error = xfs_swap_extent_rmap(&tp, ip, tip);
1781 	else
1782 		error = xfs_swap_extent_forks(tp, ip, tip, &src_log_flags,
1783 				&target_log_flags);
1784 	if (error)
1785 		goto out_trans_cancel;
1786 
1787 	/* Do we have to swap reflink flags? */
1788 	if ((ip->i_diflags2 & XFS_DIFLAG2_REFLINK) ^
1789 	    (tip->i_diflags2 & XFS_DIFLAG2_REFLINK)) {
1790 		f = ip->i_diflags2 & XFS_DIFLAG2_REFLINK;
1791 		ip->i_diflags2 &= ~XFS_DIFLAG2_REFLINK;
1792 		ip->i_diflags2 |= tip->i_diflags2 & XFS_DIFLAG2_REFLINK;
1793 		tip->i_diflags2 &= ~XFS_DIFLAG2_REFLINK;
1794 		tip->i_diflags2 |= f & XFS_DIFLAG2_REFLINK;
1795 	}
1796 
1797 	/* Swap the cow forks. */
1798 	if (xfs_has_reflink(mp)) {
1799 		ASSERT(!ip->i_cowfp ||
1800 		       ip->i_cowfp->if_format == XFS_DINODE_FMT_EXTENTS);
1801 		ASSERT(!tip->i_cowfp ||
1802 		       tip->i_cowfp->if_format == XFS_DINODE_FMT_EXTENTS);
1803 
1804 		swap(ip->i_cowfp, tip->i_cowfp);
1805 
1806 		if (ip->i_cowfp && ip->i_cowfp->if_bytes)
1807 			xfs_inode_set_cowblocks_tag(ip);
1808 		else
1809 			xfs_inode_clear_cowblocks_tag(ip);
1810 		if (tip->i_cowfp && tip->i_cowfp->if_bytes)
1811 			xfs_inode_set_cowblocks_tag(tip);
1812 		else
1813 			xfs_inode_clear_cowblocks_tag(tip);
1814 	}
1815 
1816 	xfs_trans_log_inode(tp, ip,  src_log_flags);
1817 	xfs_trans_log_inode(tp, tip, target_log_flags);
1818 
1819 	/*
1820 	 * The extent forks have been swapped, but crc=1,rmapbt=0 filesystems
1821 	 * have inode number owner values in the bmbt blocks that still refer to
1822 	 * the old inode. Scan each bmbt to fix up the owner values with the
1823 	 * inode number of the current inode.
1824 	 */
1825 	if (src_log_flags & XFS_ILOG_DOWNER) {
1826 		error = xfs_swap_change_owner(&tp, ip, tip);
1827 		if (error)
1828 			goto out_trans_cancel;
1829 	}
1830 	if (target_log_flags & XFS_ILOG_DOWNER) {
1831 		error = xfs_swap_change_owner(&tp, tip, ip);
1832 		if (error)
1833 			goto out_trans_cancel;
1834 	}
1835 
1836 	/*
1837 	 * If this is a synchronous mount, make sure that the
1838 	 * transaction goes to disk before returning to the user.
1839 	 */
1840 	if (xfs_has_wsync(mp))
1841 		xfs_trans_set_sync(tp);
1842 
1843 	error = xfs_trans_commit(tp);
1844 
1845 	trace_xfs_swap_extent_after(ip, 0);
1846 	trace_xfs_swap_extent_after(tip, 1);
1847 
1848 out_unlock_ilock:
1849 	xfs_iunlock(ip, XFS_ILOCK_EXCL);
1850 	xfs_iunlock(tip, XFS_ILOCK_EXCL);
1851 out_unlock:
1852 	filemap_invalidate_unlock_two(VFS_I(ip)->i_mapping,
1853 				      VFS_I(tip)->i_mapping);
1854 	unlock_two_nondirectories(VFS_I(ip), VFS_I(tip));
1855 	return error;
1856 
1857 out_trans_cancel:
1858 	xfs_trans_cancel(tp);
1859 	goto out_unlock_ilock;
1860 }
1861