xref: /kernel/linux/linux-6.6/fs/xfs/xfs_bmap_util.c (revision 62306a36)
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 */
39xfs_daddr_t
40xfs_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 */
54int
55xfs_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
72int
73xfs_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);
91retry:
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 */
227xfs_extnum_t
228xfs_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 */
250int
251xfs_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
298static int
299xfs_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
347static void
348xfs_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
370static inline bool
371xfs_getbmap_full(
372	struct getbmapx		*bmv)
373{
374	return bmv->bmv_length == 0 || bmv->bmv_entries >= bmv->bmv_count - 1;
375}
376
377static bool
378xfs_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 */
402int						/* error code */
403xfs_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
577out_unlock_ilock:
578	xfs_iunlock(ip, lock);
579out_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 */
590int
591xfs_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
632out_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 */
642bool
643xfs_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 */
721int
722xfs_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
764err_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);
770out_unlock:
771	xfs_iunlock(ip, XFS_ILOCK_EXCL);
772	return error;
773}
774
775int
776xfs_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		allocatesize_fsb;
784	xfs_extlen_t		extsz, temp;
785	xfs_fileoff_t		startoffset_fsb;
786	xfs_fileoff_t		endoffset_fsb;
787	int			rt;
788	xfs_trans_t		*tp;
789	xfs_bmbt_irec_t		imaps[1], *imapp;
790	int			error;
791
792	trace_xfs_alloc_file_space(ip);
793
794	if (xfs_is_shutdown(mp))
795		return -EIO;
796
797	error = xfs_qm_dqattach(ip);
798	if (error)
799		return error;
800
801	if (len <= 0)
802		return -EINVAL;
803
804	rt = XFS_IS_REALTIME_INODE(ip);
805	extsz = xfs_get_extsz_hint(ip);
806
807	count = len;
808	imapp = &imaps[0];
809	startoffset_fsb	= XFS_B_TO_FSBT(mp, offset);
810	endoffset_fsb = XFS_B_TO_FSB(mp, offset + count);
811	allocatesize_fsb = endoffset_fsb - startoffset_fsb;
812
813	/*
814	 * Allocate file space until done or until there is an error
815	 */
816	while (allocatesize_fsb && !error) {
817		xfs_fileoff_t	s, e;
818		unsigned int	dblocks, rblocks, resblks;
819		int		nimaps = 1;
820
821		/*
822		 * Determine space reservations for data/realtime.
823		 */
824		if (unlikely(extsz)) {
825			s = startoffset_fsb;
826			do_div(s, extsz);
827			s *= extsz;
828			e = startoffset_fsb + allocatesize_fsb;
829			div_u64_rem(startoffset_fsb, extsz, &temp);
830			if (temp)
831				e += temp;
832			div_u64_rem(e, extsz, &temp);
833			if (temp)
834				e += extsz - temp;
835		} else {
836			s = 0;
837			e = allocatesize_fsb;
838		}
839
840		/*
841		 * The transaction reservation is limited to a 32-bit block
842		 * count, hence we need to limit the number of blocks we are
843		 * trying to reserve to avoid an overflow. We can't allocate
844		 * more than @nimaps extents, and an extent is limited on disk
845		 * to XFS_BMBT_MAX_EXTLEN (21 bits), so use that to enforce the
846		 * limit.
847		 */
848		resblks = min_t(xfs_fileoff_t, (e - s),
849				(XFS_MAX_BMBT_EXTLEN * nimaps));
850		if (unlikely(rt)) {
851			dblocks = XFS_DIOSTRAT_SPACE_RES(mp, 0);
852			rblocks = resblks;
853		} else {
854			dblocks = XFS_DIOSTRAT_SPACE_RES(mp, resblks);
855			rblocks = 0;
856		}
857
858		error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write,
859				dblocks, rblocks, false, &tp);
860		if (error)
861			break;
862
863		error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK,
864				XFS_IEXT_ADD_NOSPLIT_CNT);
865		if (error == -EFBIG)
866			error = xfs_iext_count_upgrade(tp, ip,
867					XFS_IEXT_ADD_NOSPLIT_CNT);
868		if (error)
869			goto error;
870
871		error = xfs_bmapi_write(tp, ip, startoffset_fsb,
872				allocatesize_fsb, XFS_BMAPI_PREALLOC, 0, imapp,
873				&nimaps);
874		if (error)
875			goto error;
876
877		ip->i_diflags |= XFS_DIFLAG_PREALLOC;
878		xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
879
880		error = xfs_trans_commit(tp);
881		xfs_iunlock(ip, XFS_ILOCK_EXCL);
882		if (error)
883			break;
884
885		/*
886		 * If the allocator cannot find a single free extent large
887		 * enough to cover the start block of the requested range,
888		 * xfs_bmapi_write will return 0 but leave *nimaps set to 0.
889		 *
890		 * In that case we simply need to keep looping with the same
891		 * startoffset_fsb so that one of the following allocations
892		 * will eventually reach the requested range.
893		 */
894		if (nimaps) {
895			startoffset_fsb += imapp->br_blockcount;
896			allocatesize_fsb -= imapp->br_blockcount;
897		}
898	}
899
900	return error;
901
902error:
903	xfs_trans_cancel(tp);
904	xfs_iunlock(ip, XFS_ILOCK_EXCL);
905	return error;
906}
907
908static int
909xfs_unmap_extent(
910	struct xfs_inode	*ip,
911	xfs_fileoff_t		startoffset_fsb,
912	xfs_filblks_t		len_fsb,
913	int			*done)
914{
915	struct xfs_mount	*mp = ip->i_mount;
916	struct xfs_trans	*tp;
917	uint			resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0);
918	int			error;
919
920	error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write, resblks, 0,
921			false, &tp);
922	if (error)
923		return error;
924
925	error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK,
926			XFS_IEXT_PUNCH_HOLE_CNT);
927	if (error == -EFBIG)
928		error = xfs_iext_count_upgrade(tp, ip, XFS_IEXT_PUNCH_HOLE_CNT);
929	if (error)
930		goto out_trans_cancel;
931
932	error = xfs_bunmapi(tp, ip, startoffset_fsb, len_fsb, 0, 2, done);
933	if (error)
934		goto out_trans_cancel;
935
936	error = xfs_trans_commit(tp);
937out_unlock:
938	xfs_iunlock(ip, XFS_ILOCK_EXCL);
939	return error;
940
941out_trans_cancel:
942	xfs_trans_cancel(tp);
943	goto out_unlock;
944}
945
946/* Caller must first wait for the completion of any pending DIOs if required. */
947int
948xfs_flush_unmap_range(
949	struct xfs_inode	*ip,
950	xfs_off_t		offset,
951	xfs_off_t		len)
952{
953	struct xfs_mount	*mp = ip->i_mount;
954	struct inode		*inode = VFS_I(ip);
955	xfs_off_t		rounding, start, end;
956	int			error;
957
958	rounding = max_t(xfs_off_t, mp->m_sb.sb_blocksize, PAGE_SIZE);
959	start = round_down(offset, rounding);
960	end = round_up(offset + len, rounding) - 1;
961
962	error = filemap_write_and_wait_range(inode->i_mapping, start, end);
963	if (error)
964		return error;
965	truncate_pagecache_range(inode, start, end);
966	return 0;
967}
968
969int
970xfs_free_file_space(
971	struct xfs_inode	*ip,
972	xfs_off_t		offset,
973	xfs_off_t		len)
974{
975	struct xfs_mount	*mp = ip->i_mount;
976	xfs_fileoff_t		startoffset_fsb;
977	xfs_fileoff_t		endoffset_fsb;
978	int			done = 0, error;
979
980	trace_xfs_free_file_space(ip);
981
982	error = xfs_qm_dqattach(ip);
983	if (error)
984		return error;
985
986	if (len <= 0)	/* if nothing being freed */
987		return 0;
988
989	startoffset_fsb = XFS_B_TO_FSB(mp, offset);
990	endoffset_fsb = XFS_B_TO_FSBT(mp, offset + len);
991
992	/* We can only free complete realtime extents. */
993	if (XFS_IS_REALTIME_INODE(ip) && mp->m_sb.sb_rextsize > 1) {
994		startoffset_fsb = roundup_64(startoffset_fsb,
995					     mp->m_sb.sb_rextsize);
996		endoffset_fsb = rounddown_64(endoffset_fsb,
997					     mp->m_sb.sb_rextsize);
998	}
999
1000	/*
1001	 * Need to zero the stuff we're not freeing, on disk.
1002	 */
1003	if (endoffset_fsb > startoffset_fsb) {
1004		while (!done) {
1005			error = xfs_unmap_extent(ip, startoffset_fsb,
1006					endoffset_fsb - startoffset_fsb, &done);
1007			if (error)
1008				return error;
1009		}
1010	}
1011
1012	/*
1013	 * Now that we've unmap all full blocks we'll have to zero out any
1014	 * partial block at the beginning and/or end.  xfs_zero_range is smart
1015	 * enough to skip any holes, including those we just created, but we
1016	 * must take care not to zero beyond EOF and enlarge i_size.
1017	 */
1018	if (offset >= XFS_ISIZE(ip))
1019		return 0;
1020	if (offset + len > XFS_ISIZE(ip))
1021		len = XFS_ISIZE(ip) - offset;
1022	error = xfs_zero_range(ip, offset, len, NULL);
1023	if (error)
1024		return error;
1025
1026	/*
1027	 * If we zeroed right up to EOF and EOF straddles a page boundary we
1028	 * must make sure that the post-EOF area is also zeroed because the
1029	 * page could be mmap'd and xfs_zero_range doesn't do that for us.
1030	 * Writeback of the eof page will do this, albeit clumsily.
1031	 */
1032	if (offset + len >= XFS_ISIZE(ip) && offset_in_page(offset + len) > 0) {
1033		error = filemap_write_and_wait_range(VFS_I(ip)->i_mapping,
1034				round_down(offset + len, PAGE_SIZE), LLONG_MAX);
1035	}
1036
1037	return error;
1038}
1039
1040static int
1041xfs_prepare_shift(
1042	struct xfs_inode	*ip,
1043	loff_t			offset)
1044{
1045	struct xfs_mount	*mp = ip->i_mount;
1046	int			error;
1047
1048	/*
1049	 * Trim eofblocks to avoid shifting uninitialized post-eof preallocation
1050	 * into the accessible region of the file.
1051	 */
1052	if (xfs_can_free_eofblocks(ip, true)) {
1053		error = xfs_free_eofblocks(ip);
1054		if (error)
1055			return error;
1056	}
1057
1058	/*
1059	 * Shift operations must stabilize the start block offset boundary along
1060	 * with the full range of the operation. If we don't, a COW writeback
1061	 * completion could race with an insert, front merge with the start
1062	 * extent (after split) during the shift and corrupt the file. Start
1063	 * with the block just prior to the start to stabilize the boundary.
1064	 */
1065	offset = round_down(offset, mp->m_sb.sb_blocksize);
1066	if (offset)
1067		offset -= mp->m_sb.sb_blocksize;
1068
1069	/*
1070	 * Writeback and invalidate cache for the remainder of the file as we're
1071	 * about to shift down every extent from offset to EOF.
1072	 */
1073	error = xfs_flush_unmap_range(ip, offset, XFS_ISIZE(ip));
1074	if (error)
1075		return error;
1076
1077	/*
1078	 * Clean out anything hanging around in the cow fork now that
1079	 * we've flushed all the dirty data out to disk to avoid having
1080	 * CoW extents at the wrong offsets.
1081	 */
1082	if (xfs_inode_has_cow_data(ip)) {
1083		error = xfs_reflink_cancel_cow_range(ip, offset, NULLFILEOFF,
1084				true);
1085		if (error)
1086			return error;
1087	}
1088
1089	return 0;
1090}
1091
1092/*
1093 * xfs_collapse_file_space()
1094 *	This routine frees disk space and shift extent for the given file.
1095 *	The first thing we do is to free data blocks in the specified range
1096 *	by calling xfs_free_file_space(). It would also sync dirty data
1097 *	and invalidate page cache over the region on which collapse range
1098 *	is working. And Shift extent records to the left to cover a hole.
1099 * RETURNS:
1100 *	0 on success
1101 *	errno on error
1102 *
1103 */
1104int
1105xfs_collapse_file_space(
1106	struct xfs_inode	*ip,
1107	xfs_off_t		offset,
1108	xfs_off_t		len)
1109{
1110	struct xfs_mount	*mp = ip->i_mount;
1111	struct xfs_trans	*tp;
1112	int			error;
1113	xfs_fileoff_t		next_fsb = XFS_B_TO_FSB(mp, offset + len);
1114	xfs_fileoff_t		shift_fsb = XFS_B_TO_FSB(mp, len);
1115	bool			done = false;
1116
1117	ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL));
1118	ASSERT(xfs_isilocked(ip, XFS_MMAPLOCK_EXCL));
1119
1120	trace_xfs_collapse_file_space(ip);
1121
1122	error = xfs_free_file_space(ip, offset, len);
1123	if (error)
1124		return error;
1125
1126	error = xfs_prepare_shift(ip, offset);
1127	if (error)
1128		return error;
1129
1130	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, 0, 0, 0, &tp);
1131	if (error)
1132		return error;
1133
1134	xfs_ilock(ip, XFS_ILOCK_EXCL);
1135	xfs_trans_ijoin(tp, ip, 0);
1136
1137	while (!done) {
1138		error = xfs_bmap_collapse_extents(tp, ip, &next_fsb, shift_fsb,
1139				&done);
1140		if (error)
1141			goto out_trans_cancel;
1142		if (done)
1143			break;
1144
1145		/* finish any deferred frees and roll the transaction */
1146		error = xfs_defer_finish(&tp);
1147		if (error)
1148			goto out_trans_cancel;
1149	}
1150
1151	error = xfs_trans_commit(tp);
1152	xfs_iunlock(ip, XFS_ILOCK_EXCL);
1153	return error;
1154
1155out_trans_cancel:
1156	xfs_trans_cancel(tp);
1157	xfs_iunlock(ip, XFS_ILOCK_EXCL);
1158	return error;
1159}
1160
1161/*
1162 * xfs_insert_file_space()
1163 *	This routine create hole space by shifting extents for the given file.
1164 *	The first thing we do is to sync dirty data and invalidate page cache
1165 *	over the region on which insert range is working. And split an extent
1166 *	to two extents at given offset by calling xfs_bmap_split_extent.
1167 *	And shift all extent records which are laying between [offset,
1168 *	last allocated extent] to the right to reserve hole range.
1169 * RETURNS:
1170 *	0 on success
1171 *	errno on error
1172 */
1173int
1174xfs_insert_file_space(
1175	struct xfs_inode	*ip,
1176	loff_t			offset,
1177	loff_t			len)
1178{
1179	struct xfs_mount	*mp = ip->i_mount;
1180	struct xfs_trans	*tp;
1181	int			error;
1182	xfs_fileoff_t		stop_fsb = XFS_B_TO_FSB(mp, offset);
1183	xfs_fileoff_t		next_fsb = NULLFSBLOCK;
1184	xfs_fileoff_t		shift_fsb = XFS_B_TO_FSB(mp, len);
1185	bool			done = false;
1186
1187	ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL));
1188	ASSERT(xfs_isilocked(ip, XFS_MMAPLOCK_EXCL));
1189
1190	trace_xfs_insert_file_space(ip);
1191
1192	error = xfs_bmap_can_insert_extents(ip, stop_fsb, shift_fsb);
1193	if (error)
1194		return error;
1195
1196	error = xfs_prepare_shift(ip, offset);
1197	if (error)
1198		return error;
1199
1200	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write,
1201			XFS_DIOSTRAT_SPACE_RES(mp, 0), 0, 0, &tp);
1202	if (error)
1203		return error;
1204
1205	xfs_ilock(ip, XFS_ILOCK_EXCL);
1206	xfs_trans_ijoin(tp, ip, 0);
1207
1208	error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK,
1209			XFS_IEXT_PUNCH_HOLE_CNT);
1210	if (error == -EFBIG)
1211		error = xfs_iext_count_upgrade(tp, ip, XFS_IEXT_PUNCH_HOLE_CNT);
1212	if (error)
1213		goto out_trans_cancel;
1214
1215	/*
1216	 * The extent shifting code works on extent granularity. So, if stop_fsb
1217	 * is not the starting block of extent, we need to split the extent at
1218	 * stop_fsb.
1219	 */
1220	error = xfs_bmap_split_extent(tp, ip, stop_fsb);
1221	if (error)
1222		goto out_trans_cancel;
1223
1224	do {
1225		error = xfs_defer_finish(&tp);
1226		if (error)
1227			goto out_trans_cancel;
1228
1229		error = xfs_bmap_insert_extents(tp, ip, &next_fsb, shift_fsb,
1230				&done, stop_fsb);
1231		if (error)
1232			goto out_trans_cancel;
1233	} while (!done);
1234
1235	error = xfs_trans_commit(tp);
1236	xfs_iunlock(ip, XFS_ILOCK_EXCL);
1237	return error;
1238
1239out_trans_cancel:
1240	xfs_trans_cancel(tp);
1241	xfs_iunlock(ip, XFS_ILOCK_EXCL);
1242	return error;
1243}
1244
1245/*
1246 * We need to check that the format of the data fork in the temporary inode is
1247 * valid for the target inode before doing the swap. This is not a problem with
1248 * attr1 because of the fixed fork offset, but attr2 has a dynamically sized
1249 * data fork depending on the space the attribute fork is taking so we can get
1250 * invalid formats on the target inode.
1251 *
1252 * E.g. target has space for 7 extents in extent format, temp inode only has
1253 * space for 6.  If we defragment down to 7 extents, then the tmp format is a
1254 * btree, but when swapped it needs to be in extent format. Hence we can't just
1255 * blindly swap data forks on attr2 filesystems.
1256 *
1257 * Note that we check the swap in both directions so that we don't end up with
1258 * a corrupt temporary inode, either.
1259 *
1260 * Note that fixing the way xfs_fsr sets up the attribute fork in the source
1261 * inode will prevent this situation from occurring, so all we do here is
1262 * reject and log the attempt. basically we are putting the responsibility on
1263 * userspace to get this right.
1264 */
1265static int
1266xfs_swap_extents_check_format(
1267	struct xfs_inode	*ip,	/* target inode */
1268	struct xfs_inode	*tip)	/* tmp inode */
1269{
1270	struct xfs_ifork	*ifp = &ip->i_df;
1271	struct xfs_ifork	*tifp = &tip->i_df;
1272
1273	/* User/group/project quota ids must match if quotas are enforced. */
1274	if (XFS_IS_QUOTA_ON(ip->i_mount) &&
1275	    (!uid_eq(VFS_I(ip)->i_uid, VFS_I(tip)->i_uid) ||
1276	     !gid_eq(VFS_I(ip)->i_gid, VFS_I(tip)->i_gid) ||
1277	     ip->i_projid != tip->i_projid))
1278		return -EINVAL;
1279
1280	/* Should never get a local format */
1281	if (ifp->if_format == XFS_DINODE_FMT_LOCAL ||
1282	    tifp->if_format == XFS_DINODE_FMT_LOCAL)
1283		return -EINVAL;
1284
1285	/*
1286	 * if the target inode has less extents that then temporary inode then
1287	 * why did userspace call us?
1288	 */
1289	if (ifp->if_nextents < tifp->if_nextents)
1290		return -EINVAL;
1291
1292	/*
1293	 * If we have to use the (expensive) rmap swap method, we can
1294	 * handle any number of extents and any format.
1295	 */
1296	if (xfs_has_rmapbt(ip->i_mount))
1297		return 0;
1298
1299	/*
1300	 * if the target inode is in extent form and the temp inode is in btree
1301	 * form then we will end up with the target inode in the wrong format
1302	 * as we already know there are less extents in the temp inode.
1303	 */
1304	if (ifp->if_format == XFS_DINODE_FMT_EXTENTS &&
1305	    tifp->if_format == XFS_DINODE_FMT_BTREE)
1306		return -EINVAL;
1307
1308	/* Check temp in extent form to max in target */
1309	if (tifp->if_format == XFS_DINODE_FMT_EXTENTS &&
1310	    tifp->if_nextents > XFS_IFORK_MAXEXT(ip, XFS_DATA_FORK))
1311		return -EINVAL;
1312
1313	/* Check target in extent form to max in temp */
1314	if (ifp->if_format == XFS_DINODE_FMT_EXTENTS &&
1315	    ifp->if_nextents > XFS_IFORK_MAXEXT(tip, XFS_DATA_FORK))
1316		return -EINVAL;
1317
1318	/*
1319	 * If we are in a btree format, check that the temp root block will fit
1320	 * in the target and that it has enough extents to be in btree format
1321	 * in the target.
1322	 *
1323	 * Note that we have to be careful to allow btree->extent conversions
1324	 * (a common defrag case) which will occur when the temp inode is in
1325	 * extent format...
1326	 */
1327	if (tifp->if_format == XFS_DINODE_FMT_BTREE) {
1328		if (xfs_inode_has_attr_fork(ip) &&
1329		    XFS_BMAP_BMDR_SPACE(tifp->if_broot) > xfs_inode_fork_boff(ip))
1330			return -EINVAL;
1331		if (tifp->if_nextents <= XFS_IFORK_MAXEXT(ip, XFS_DATA_FORK))
1332			return -EINVAL;
1333	}
1334
1335	/* Reciprocal target->temp btree format checks */
1336	if (ifp->if_format == XFS_DINODE_FMT_BTREE) {
1337		if (xfs_inode_has_attr_fork(tip) &&
1338		    XFS_BMAP_BMDR_SPACE(ip->i_df.if_broot) > xfs_inode_fork_boff(tip))
1339			return -EINVAL;
1340		if (ifp->if_nextents <= XFS_IFORK_MAXEXT(tip, XFS_DATA_FORK))
1341			return -EINVAL;
1342	}
1343
1344	return 0;
1345}
1346
1347static int
1348xfs_swap_extent_flush(
1349	struct xfs_inode	*ip)
1350{
1351	int	error;
1352
1353	error = filemap_write_and_wait(VFS_I(ip)->i_mapping);
1354	if (error)
1355		return error;
1356	truncate_pagecache_range(VFS_I(ip), 0, -1);
1357
1358	/* Verify O_DIRECT for ftmp */
1359	if (VFS_I(ip)->i_mapping->nrpages)
1360		return -EINVAL;
1361	return 0;
1362}
1363
1364/*
1365 * Move extents from one file to another, when rmap is enabled.
1366 */
1367STATIC int
1368xfs_swap_extent_rmap(
1369	struct xfs_trans		**tpp,
1370	struct xfs_inode		*ip,
1371	struct xfs_inode		*tip)
1372{
1373	struct xfs_trans		*tp = *tpp;
1374	struct xfs_bmbt_irec		irec;
1375	struct xfs_bmbt_irec		uirec;
1376	struct xfs_bmbt_irec		tirec;
1377	xfs_fileoff_t			offset_fsb;
1378	xfs_fileoff_t			end_fsb;
1379	xfs_filblks_t			count_fsb;
1380	int				error;
1381	xfs_filblks_t			ilen;
1382	xfs_filblks_t			rlen;
1383	int				nimaps;
1384	uint64_t			tip_flags2;
1385
1386	/*
1387	 * If the source file has shared blocks, we must flag the donor
1388	 * file as having shared blocks so that we get the shared-block
1389	 * rmap functions when we go to fix up the rmaps.  The flags
1390	 * will be switch for reals later.
1391	 */
1392	tip_flags2 = tip->i_diflags2;
1393	if (ip->i_diflags2 & XFS_DIFLAG2_REFLINK)
1394		tip->i_diflags2 |= XFS_DIFLAG2_REFLINK;
1395
1396	offset_fsb = 0;
1397	end_fsb = XFS_B_TO_FSB(ip->i_mount, i_size_read(VFS_I(ip)));
1398	count_fsb = (xfs_filblks_t)(end_fsb - offset_fsb);
1399
1400	while (count_fsb) {
1401		/* Read extent from the donor file */
1402		nimaps = 1;
1403		error = xfs_bmapi_read(tip, offset_fsb, count_fsb, &tirec,
1404				&nimaps, 0);
1405		if (error)
1406			goto out;
1407		ASSERT(nimaps == 1);
1408		ASSERT(tirec.br_startblock != DELAYSTARTBLOCK);
1409
1410		trace_xfs_swap_extent_rmap_remap(tip, &tirec);
1411		ilen = tirec.br_blockcount;
1412
1413		/* Unmap the old blocks in the source file. */
1414		while (tirec.br_blockcount) {
1415			ASSERT(tp->t_highest_agno == NULLAGNUMBER);
1416			trace_xfs_swap_extent_rmap_remap_piece(tip, &tirec);
1417
1418			/* Read extent from the source file */
1419			nimaps = 1;
1420			error = xfs_bmapi_read(ip, tirec.br_startoff,
1421					tirec.br_blockcount, &irec,
1422					&nimaps, 0);
1423			if (error)
1424				goto out;
1425			ASSERT(nimaps == 1);
1426			ASSERT(tirec.br_startoff == irec.br_startoff);
1427			trace_xfs_swap_extent_rmap_remap_piece(ip, &irec);
1428
1429			/* Trim the extent. */
1430			uirec = tirec;
1431			uirec.br_blockcount = rlen = min_t(xfs_filblks_t,
1432					tirec.br_blockcount,
1433					irec.br_blockcount);
1434			trace_xfs_swap_extent_rmap_remap_piece(tip, &uirec);
1435
1436			if (xfs_bmap_is_real_extent(&uirec)) {
1437				error = xfs_iext_count_may_overflow(ip,
1438						XFS_DATA_FORK,
1439						XFS_IEXT_SWAP_RMAP_CNT);
1440				if (error == -EFBIG)
1441					error = xfs_iext_count_upgrade(tp, ip,
1442							XFS_IEXT_SWAP_RMAP_CNT);
1443				if (error)
1444					goto out;
1445			}
1446
1447			if (xfs_bmap_is_real_extent(&irec)) {
1448				error = xfs_iext_count_may_overflow(tip,
1449						XFS_DATA_FORK,
1450						XFS_IEXT_SWAP_RMAP_CNT);
1451				if (error == -EFBIG)
1452					error = xfs_iext_count_upgrade(tp, ip,
1453							XFS_IEXT_SWAP_RMAP_CNT);
1454				if (error)
1455					goto out;
1456			}
1457
1458			/* Remove the mapping from the donor file. */
1459			xfs_bmap_unmap_extent(tp, tip, &uirec);
1460
1461			/* Remove the mapping from the source file. */
1462			xfs_bmap_unmap_extent(tp, ip, &irec);
1463
1464			/* Map the donor file's blocks into the source file. */
1465			xfs_bmap_map_extent(tp, ip, &uirec);
1466
1467			/* Map the source file's blocks into the donor file. */
1468			xfs_bmap_map_extent(tp, tip, &irec);
1469
1470			error = xfs_defer_finish(tpp);
1471			tp = *tpp;
1472			if (error)
1473				goto out;
1474
1475			tirec.br_startoff += rlen;
1476			if (tirec.br_startblock != HOLESTARTBLOCK &&
1477			    tirec.br_startblock != DELAYSTARTBLOCK)
1478				tirec.br_startblock += rlen;
1479			tirec.br_blockcount -= rlen;
1480		}
1481
1482		/* Roll on... */
1483		count_fsb -= ilen;
1484		offset_fsb += ilen;
1485	}
1486
1487	tip->i_diflags2 = tip_flags2;
1488	return 0;
1489
1490out:
1491	trace_xfs_swap_extent_rmap_error(ip, error, _RET_IP_);
1492	tip->i_diflags2 = tip_flags2;
1493	return error;
1494}
1495
1496/* Swap the extents of two files by swapping data forks. */
1497STATIC int
1498xfs_swap_extent_forks(
1499	struct xfs_trans	*tp,
1500	struct xfs_inode	*ip,
1501	struct xfs_inode	*tip,
1502	int			*src_log_flags,
1503	int			*target_log_flags)
1504{
1505	xfs_filblks_t		aforkblks = 0;
1506	xfs_filblks_t		taforkblks = 0;
1507	xfs_extnum_t		junk;
1508	uint64_t		tmp;
1509	int			error;
1510
1511	/*
1512	 * Count the number of extended attribute blocks
1513	 */
1514	if (xfs_inode_has_attr_fork(ip) && ip->i_af.if_nextents > 0 &&
1515	    ip->i_af.if_format != XFS_DINODE_FMT_LOCAL) {
1516		error = xfs_bmap_count_blocks(tp, ip, XFS_ATTR_FORK, &junk,
1517				&aforkblks);
1518		if (error)
1519			return error;
1520	}
1521	if (xfs_inode_has_attr_fork(tip) && tip->i_af.if_nextents > 0 &&
1522	    tip->i_af.if_format != XFS_DINODE_FMT_LOCAL) {
1523		error = xfs_bmap_count_blocks(tp, tip, XFS_ATTR_FORK, &junk,
1524				&taforkblks);
1525		if (error)
1526			return error;
1527	}
1528
1529	/*
1530	 * Btree format (v3) inodes have the inode number stamped in the bmbt
1531	 * block headers. We can't start changing the bmbt blocks until the
1532	 * inode owner change is logged so recovery does the right thing in the
1533	 * event of a crash. Set the owner change log flags now and leave the
1534	 * bmbt scan as the last step.
1535	 */
1536	if (xfs_has_v3inodes(ip->i_mount)) {
1537		if (ip->i_df.if_format == XFS_DINODE_FMT_BTREE)
1538			(*target_log_flags) |= XFS_ILOG_DOWNER;
1539		if (tip->i_df.if_format == XFS_DINODE_FMT_BTREE)
1540			(*src_log_flags) |= XFS_ILOG_DOWNER;
1541	}
1542
1543	/*
1544	 * Swap the data forks of the inodes
1545	 */
1546	swap(ip->i_df, tip->i_df);
1547
1548	/*
1549	 * Fix the on-disk inode values
1550	 */
1551	tmp = (uint64_t)ip->i_nblocks;
1552	ip->i_nblocks = tip->i_nblocks - taforkblks + aforkblks;
1553	tip->i_nblocks = tmp + taforkblks - aforkblks;
1554
1555	/*
1556	 * The extents in the source inode could still contain speculative
1557	 * preallocation beyond EOF (e.g. the file is open but not modified
1558	 * while defrag is in progress). In that case, we need to copy over the
1559	 * number of delalloc blocks the data fork in the source inode is
1560	 * tracking beyond EOF so that when the fork is truncated away when the
1561	 * temporary inode is unlinked we don't underrun the i_delayed_blks
1562	 * counter on that inode.
1563	 */
1564	ASSERT(tip->i_delayed_blks == 0);
1565	tip->i_delayed_blks = ip->i_delayed_blks;
1566	ip->i_delayed_blks = 0;
1567
1568	switch (ip->i_df.if_format) {
1569	case XFS_DINODE_FMT_EXTENTS:
1570		(*src_log_flags) |= XFS_ILOG_DEXT;
1571		break;
1572	case XFS_DINODE_FMT_BTREE:
1573		ASSERT(!xfs_has_v3inodes(ip->i_mount) ||
1574		       (*src_log_flags & XFS_ILOG_DOWNER));
1575		(*src_log_flags) |= XFS_ILOG_DBROOT;
1576		break;
1577	}
1578
1579	switch (tip->i_df.if_format) {
1580	case XFS_DINODE_FMT_EXTENTS:
1581		(*target_log_flags) |= XFS_ILOG_DEXT;
1582		break;
1583	case XFS_DINODE_FMT_BTREE:
1584		(*target_log_flags) |= XFS_ILOG_DBROOT;
1585		ASSERT(!xfs_has_v3inodes(ip->i_mount) ||
1586		       (*target_log_flags & XFS_ILOG_DOWNER));
1587		break;
1588	}
1589
1590	return 0;
1591}
1592
1593/*
1594 * Fix up the owners of the bmbt blocks to refer to the current inode. The
1595 * change owner scan attempts to order all modified buffers in the current
1596 * transaction. In the event of ordered buffer failure, the offending buffer is
1597 * physically logged as a fallback and the scan returns -EAGAIN. We must roll
1598 * the transaction in this case to replenish the fallback log reservation and
1599 * restart the scan. This process repeats until the scan completes.
1600 */
1601static int
1602xfs_swap_change_owner(
1603	struct xfs_trans	**tpp,
1604	struct xfs_inode	*ip,
1605	struct xfs_inode	*tmpip)
1606{
1607	int			error;
1608	struct xfs_trans	*tp = *tpp;
1609
1610	do {
1611		error = xfs_bmbt_change_owner(tp, ip, XFS_DATA_FORK, ip->i_ino,
1612					      NULL);
1613		/* success or fatal error */
1614		if (error != -EAGAIN)
1615			break;
1616
1617		error = xfs_trans_roll(tpp);
1618		if (error)
1619			break;
1620		tp = *tpp;
1621
1622		/*
1623		 * Redirty both inodes so they can relog and keep the log tail
1624		 * moving forward.
1625		 */
1626		xfs_trans_ijoin(tp, ip, 0);
1627		xfs_trans_ijoin(tp, tmpip, 0);
1628		xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
1629		xfs_trans_log_inode(tp, tmpip, XFS_ILOG_CORE);
1630	} while (true);
1631
1632	return error;
1633}
1634
1635int
1636xfs_swap_extents(
1637	struct xfs_inode	*ip,	/* target inode */
1638	struct xfs_inode	*tip,	/* tmp inode */
1639	struct xfs_swapext	*sxp)
1640{
1641	struct xfs_mount	*mp = ip->i_mount;
1642	struct xfs_trans	*tp;
1643	struct xfs_bstat	*sbp = &sxp->sx_stat;
1644	int			src_log_flags, target_log_flags;
1645	int			error = 0;
1646	uint64_t		f;
1647	int			resblks = 0;
1648	unsigned int		flags = 0;
1649	struct timespec64	ctime;
1650
1651	/*
1652	 * Lock the inodes against other IO, page faults and truncate to
1653	 * begin with.  Then we can ensure the inodes are flushed and have no
1654	 * page cache safely. Once we have done this we can take the ilocks and
1655	 * do the rest of the checks.
1656	 */
1657	lock_two_nondirectories(VFS_I(ip), VFS_I(tip));
1658	filemap_invalidate_lock_two(VFS_I(ip)->i_mapping,
1659				    VFS_I(tip)->i_mapping);
1660
1661	/* Verify that both files have the same format */
1662	if ((VFS_I(ip)->i_mode & S_IFMT) != (VFS_I(tip)->i_mode & S_IFMT)) {
1663		error = -EINVAL;
1664		goto out_unlock;
1665	}
1666
1667	/* Verify both files are either real-time or non-realtime */
1668	if (XFS_IS_REALTIME_INODE(ip) != XFS_IS_REALTIME_INODE(tip)) {
1669		error = -EINVAL;
1670		goto out_unlock;
1671	}
1672
1673	error = xfs_qm_dqattach(ip);
1674	if (error)
1675		goto out_unlock;
1676
1677	error = xfs_qm_dqattach(tip);
1678	if (error)
1679		goto out_unlock;
1680
1681	error = xfs_swap_extent_flush(ip);
1682	if (error)
1683		goto out_unlock;
1684	error = xfs_swap_extent_flush(tip);
1685	if (error)
1686		goto out_unlock;
1687
1688	if (xfs_inode_has_cow_data(tip)) {
1689		error = xfs_reflink_cancel_cow_range(tip, 0, NULLFILEOFF, true);
1690		if (error)
1691			goto out_unlock;
1692	}
1693
1694	/*
1695	 * Extent "swapping" with rmap requires a permanent reservation and
1696	 * a block reservation because it's really just a remap operation
1697	 * performed with log redo items!
1698	 */
1699	if (xfs_has_rmapbt(mp)) {
1700		int		w = XFS_DATA_FORK;
1701		uint32_t	ipnext = ip->i_df.if_nextents;
1702		uint32_t	tipnext	= tip->i_df.if_nextents;
1703
1704		/*
1705		 * Conceptually this shouldn't affect the shape of either bmbt,
1706		 * but since we atomically move extents one by one, we reserve
1707		 * enough space to rebuild both trees.
1708		 */
1709		resblks = XFS_SWAP_RMAP_SPACE_RES(mp, ipnext, w);
1710		resblks +=  XFS_SWAP_RMAP_SPACE_RES(mp, tipnext, w);
1711
1712		/*
1713		 * If either inode straddles a bmapbt block allocation boundary,
1714		 * the rmapbt algorithm triggers repeated allocs and frees as
1715		 * extents are remapped. This can exhaust the block reservation
1716		 * prematurely and cause shutdown. Return freed blocks to the
1717		 * transaction reservation to counter this behavior.
1718		 */
1719		flags |= XFS_TRANS_RES_FDBLKS;
1720	}
1721	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, 0, flags,
1722				&tp);
1723	if (error)
1724		goto out_unlock;
1725
1726	/*
1727	 * Lock and join the inodes to the tansaction so that transaction commit
1728	 * or cancel will unlock the inodes from this point onwards.
1729	 */
1730	xfs_lock_two_inodes(ip, XFS_ILOCK_EXCL, tip, XFS_ILOCK_EXCL);
1731	xfs_trans_ijoin(tp, ip, 0);
1732	xfs_trans_ijoin(tp, tip, 0);
1733
1734
1735	/* Verify all data are being swapped */
1736	if (sxp->sx_offset != 0 ||
1737	    sxp->sx_length != ip->i_disk_size ||
1738	    sxp->sx_length != tip->i_disk_size) {
1739		error = -EFAULT;
1740		goto out_trans_cancel;
1741	}
1742
1743	trace_xfs_swap_extent_before(ip, 0);
1744	trace_xfs_swap_extent_before(tip, 1);
1745
1746	/* check inode formats now that data is flushed */
1747	error = xfs_swap_extents_check_format(ip, tip);
1748	if (error) {
1749		xfs_notice(mp,
1750		    "%s: inode 0x%llx format is incompatible for exchanging.",
1751				__func__, ip->i_ino);
1752		goto out_trans_cancel;
1753	}
1754
1755	/*
1756	 * Compare the current change & modify times with that
1757	 * passed in.  If they differ, we abort this swap.
1758	 * This is the mechanism used to ensure the calling
1759	 * process that the file was not changed out from
1760	 * under it.
1761	 */
1762	ctime = inode_get_ctime(VFS_I(ip));
1763	if ((sbp->bs_ctime.tv_sec != ctime.tv_sec) ||
1764	    (sbp->bs_ctime.tv_nsec != ctime.tv_nsec) ||
1765	    (sbp->bs_mtime.tv_sec != VFS_I(ip)->i_mtime.tv_sec) ||
1766	    (sbp->bs_mtime.tv_nsec != VFS_I(ip)->i_mtime.tv_nsec)) {
1767		error = -EBUSY;
1768		goto out_trans_cancel;
1769	}
1770
1771	/*
1772	 * Note the trickiness in setting the log flags - we set the owner log
1773	 * flag on the opposite inode (i.e. the inode we are setting the new
1774	 * owner to be) because once we swap the forks and log that, log
1775	 * recovery is going to see the fork as owned by the swapped inode,
1776	 * not the pre-swapped inodes.
1777	 */
1778	src_log_flags = XFS_ILOG_CORE;
1779	target_log_flags = XFS_ILOG_CORE;
1780
1781	if (xfs_has_rmapbt(mp))
1782		error = xfs_swap_extent_rmap(&tp, ip, tip);
1783	else
1784		error = xfs_swap_extent_forks(tp, ip, tip, &src_log_flags,
1785				&target_log_flags);
1786	if (error)
1787		goto out_trans_cancel;
1788
1789	/* Do we have to swap reflink flags? */
1790	if ((ip->i_diflags2 & XFS_DIFLAG2_REFLINK) ^
1791	    (tip->i_diflags2 & XFS_DIFLAG2_REFLINK)) {
1792		f = ip->i_diflags2 & XFS_DIFLAG2_REFLINK;
1793		ip->i_diflags2 &= ~XFS_DIFLAG2_REFLINK;
1794		ip->i_diflags2 |= tip->i_diflags2 & XFS_DIFLAG2_REFLINK;
1795		tip->i_diflags2 &= ~XFS_DIFLAG2_REFLINK;
1796		tip->i_diflags2 |= f & XFS_DIFLAG2_REFLINK;
1797	}
1798
1799	/* Swap the cow forks. */
1800	if (xfs_has_reflink(mp)) {
1801		ASSERT(!ip->i_cowfp ||
1802		       ip->i_cowfp->if_format == XFS_DINODE_FMT_EXTENTS);
1803		ASSERT(!tip->i_cowfp ||
1804		       tip->i_cowfp->if_format == XFS_DINODE_FMT_EXTENTS);
1805
1806		swap(ip->i_cowfp, tip->i_cowfp);
1807
1808		if (ip->i_cowfp && ip->i_cowfp->if_bytes)
1809			xfs_inode_set_cowblocks_tag(ip);
1810		else
1811			xfs_inode_clear_cowblocks_tag(ip);
1812		if (tip->i_cowfp && tip->i_cowfp->if_bytes)
1813			xfs_inode_set_cowblocks_tag(tip);
1814		else
1815			xfs_inode_clear_cowblocks_tag(tip);
1816	}
1817
1818	xfs_trans_log_inode(tp, ip,  src_log_flags);
1819	xfs_trans_log_inode(tp, tip, target_log_flags);
1820
1821	/*
1822	 * The extent forks have been swapped, but crc=1,rmapbt=0 filesystems
1823	 * have inode number owner values in the bmbt blocks that still refer to
1824	 * the old inode. Scan each bmbt to fix up the owner values with the
1825	 * inode number of the current inode.
1826	 */
1827	if (src_log_flags & XFS_ILOG_DOWNER) {
1828		error = xfs_swap_change_owner(&tp, ip, tip);
1829		if (error)
1830			goto out_trans_cancel;
1831	}
1832	if (target_log_flags & XFS_ILOG_DOWNER) {
1833		error = xfs_swap_change_owner(&tp, tip, ip);
1834		if (error)
1835			goto out_trans_cancel;
1836	}
1837
1838	/*
1839	 * If this is a synchronous mount, make sure that the
1840	 * transaction goes to disk before returning to the user.
1841	 */
1842	if (xfs_has_wsync(mp))
1843		xfs_trans_set_sync(tp);
1844
1845	error = xfs_trans_commit(tp);
1846
1847	trace_xfs_swap_extent_after(ip, 0);
1848	trace_xfs_swap_extent_after(tip, 1);
1849
1850out_unlock_ilock:
1851	xfs_iunlock(ip, XFS_ILOCK_EXCL);
1852	xfs_iunlock(tip, XFS_ILOCK_EXCL);
1853out_unlock:
1854	filemap_invalidate_unlock_two(VFS_I(ip)->i_mapping,
1855				      VFS_I(tip)->i_mapping);
1856	unlock_two_nondirectories(VFS_I(ip), VFS_I(tip));
1857	return error;
1858
1859out_trans_cancel:
1860	xfs_trans_cancel(tp);
1861	goto out_unlock_ilock;
1862}
1863