1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (c) 2000-2006 Silicon Graphics, Inc.
4  * Copyright (c) 2016-2018 Christoph Hellwig.
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_mount.h"
14 #include "xfs_inode.h"
15 #include "xfs_btree.h"
16 #include "xfs_bmap_btree.h"
17 #include "xfs_bmap.h"
18 #include "xfs_bmap_util.h"
19 #include "xfs_errortag.h"
20 #include "xfs_error.h"
21 #include "xfs_trans.h"
22 #include "xfs_trans_space.h"
23 #include "xfs_inode_item.h"
24 #include "xfs_iomap.h"
25 #include "xfs_trace.h"
26 #include "xfs_quota.h"
27 #include "xfs_dquot_item.h"
28 #include "xfs_dquot.h"
29 #include "xfs_reflink.h"
30 
31 #define XFS_ALLOC_ALIGN(mp, off) \
32 	(((off) >> mp->m_allocsize_log) << mp->m_allocsize_log)
33 
34 static int
xfs_alert_fsblock_zero(xfs_inode_t * ip,xfs_bmbt_irec_t * imap)35 xfs_alert_fsblock_zero(
36 	xfs_inode_t	*ip,
37 	xfs_bmbt_irec_t	*imap)
38 {
39 	xfs_alert_tag(ip->i_mount, XFS_PTAG_FSBLOCK_ZERO,
40 			"Access to block zero in inode %llu "
41 			"start_block: %llx start_off: %llx "
42 			"blkcnt: %llx extent-state: %x",
43 		(unsigned long long)ip->i_ino,
44 		(unsigned long long)imap->br_startblock,
45 		(unsigned long long)imap->br_startoff,
46 		(unsigned long long)imap->br_blockcount,
47 		imap->br_state);
48 	return -EFSCORRUPTED;
49 }
50 
51 u64
xfs_iomap_inode_sequence(struct xfs_inode * ip,u16 iomap_flags)52 xfs_iomap_inode_sequence(
53 	struct xfs_inode	*ip,
54 	u16			iomap_flags)
55 {
56 	u64			cookie = 0;
57 
58 	if (iomap_flags & IOMAP_F_XATTR)
59 		return READ_ONCE(ip->i_af.if_seq);
60 	if ((iomap_flags & IOMAP_F_SHARED) && ip->i_cowfp)
61 		cookie = (u64)READ_ONCE(ip->i_cowfp->if_seq) << 32;
62 	return cookie | READ_ONCE(ip->i_df.if_seq);
63 }
64 
65 /*
66  * Check that the iomap passed to us is still valid for the given offset and
67  * length.
68  */
69 static bool
xfs_iomap_valid(struct inode * inode,const struct iomap * iomap)70 xfs_iomap_valid(
71 	struct inode		*inode,
72 	const struct iomap	*iomap)
73 {
74 	struct xfs_inode	*ip = XFS_I(inode);
75 
76 	if (iomap->validity_cookie !=
77 			xfs_iomap_inode_sequence(ip, iomap->flags)) {
78 		trace_xfs_iomap_invalid(ip, iomap);
79 		return false;
80 	}
81 
82 	XFS_ERRORTAG_DELAY(ip->i_mount, XFS_ERRTAG_WRITE_DELAY_MS);
83 	return true;
84 }
85 
86 static const struct iomap_folio_ops xfs_iomap_folio_ops = {
87 	.iomap_valid		= xfs_iomap_valid,
88 };
89 
90 int
xfs_bmbt_to_iomap(struct xfs_inode * ip,struct iomap * iomap,struct xfs_bmbt_irec * imap,unsigned int mapping_flags,u16 iomap_flags,u64 sequence_cookie)91 xfs_bmbt_to_iomap(
92 	struct xfs_inode	*ip,
93 	struct iomap		*iomap,
94 	struct xfs_bmbt_irec	*imap,
95 	unsigned int		mapping_flags,
96 	u16			iomap_flags,
97 	u64			sequence_cookie)
98 {
99 	struct xfs_mount	*mp = ip->i_mount;
100 	struct xfs_buftarg	*target = xfs_inode_buftarg(ip);
101 
102 	if (unlikely(!xfs_valid_startblock(ip, imap->br_startblock)))
103 		return xfs_alert_fsblock_zero(ip, imap);
104 
105 	if (imap->br_startblock == HOLESTARTBLOCK) {
106 		iomap->addr = IOMAP_NULL_ADDR;
107 		iomap->type = IOMAP_HOLE;
108 	} else if (imap->br_startblock == DELAYSTARTBLOCK ||
109 		   isnullstartblock(imap->br_startblock)) {
110 		iomap->addr = IOMAP_NULL_ADDR;
111 		iomap->type = IOMAP_DELALLOC;
112 	} else {
113 		iomap->addr = BBTOB(xfs_fsb_to_db(ip, imap->br_startblock));
114 		if (mapping_flags & IOMAP_DAX)
115 			iomap->addr += target->bt_dax_part_off;
116 
117 		if (imap->br_state == XFS_EXT_UNWRITTEN)
118 			iomap->type = IOMAP_UNWRITTEN;
119 		else
120 			iomap->type = IOMAP_MAPPED;
121 
122 	}
123 	iomap->offset = XFS_FSB_TO_B(mp, imap->br_startoff);
124 	iomap->length = XFS_FSB_TO_B(mp, imap->br_blockcount);
125 	if (mapping_flags & IOMAP_DAX)
126 		iomap->dax_dev = target->bt_daxdev;
127 	else
128 		iomap->bdev = target->bt_bdev;
129 	iomap->flags = iomap_flags;
130 
131 	if (xfs_ipincount(ip) &&
132 	    (ip->i_itemp->ili_fsync_fields & ~XFS_ILOG_TIMESTAMP))
133 		iomap->flags |= IOMAP_F_DIRTY;
134 
135 	iomap->validity_cookie = sequence_cookie;
136 	iomap->folio_ops = &xfs_iomap_folio_ops;
137 	return 0;
138 }
139 
140 static void
xfs_hole_to_iomap(struct xfs_inode * ip,struct iomap * iomap,xfs_fileoff_t offset_fsb,xfs_fileoff_t end_fsb)141 xfs_hole_to_iomap(
142 	struct xfs_inode	*ip,
143 	struct iomap		*iomap,
144 	xfs_fileoff_t		offset_fsb,
145 	xfs_fileoff_t		end_fsb)
146 {
147 	struct xfs_buftarg	*target = xfs_inode_buftarg(ip);
148 
149 	iomap->addr = IOMAP_NULL_ADDR;
150 	iomap->type = IOMAP_HOLE;
151 	iomap->offset = XFS_FSB_TO_B(ip->i_mount, offset_fsb);
152 	iomap->length = XFS_FSB_TO_B(ip->i_mount, end_fsb - offset_fsb);
153 	iomap->bdev = target->bt_bdev;
154 	iomap->dax_dev = target->bt_daxdev;
155 }
156 
157 static inline xfs_fileoff_t
xfs_iomap_end_fsb(struct xfs_mount * mp,loff_t offset,loff_t count)158 xfs_iomap_end_fsb(
159 	struct xfs_mount	*mp,
160 	loff_t			offset,
161 	loff_t			count)
162 {
163 	ASSERT(offset <= mp->m_super->s_maxbytes);
164 	return min(XFS_B_TO_FSB(mp, offset + count),
165 		   XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes));
166 }
167 
168 static xfs_extlen_t
xfs_eof_alignment(struct xfs_inode * ip)169 xfs_eof_alignment(
170 	struct xfs_inode	*ip)
171 {
172 	struct xfs_mount	*mp = ip->i_mount;
173 	xfs_extlen_t		align = 0;
174 
175 	if (!XFS_IS_REALTIME_INODE(ip)) {
176 		/*
177 		 * Round up the allocation request to a stripe unit
178 		 * (m_dalign) boundary if the file size is >= stripe unit
179 		 * size, and we are allocating past the allocation eof.
180 		 *
181 		 * If mounted with the "-o swalloc" option the alignment is
182 		 * increased from the strip unit size to the stripe width.
183 		 */
184 		if (mp->m_swidth && xfs_has_swalloc(mp))
185 			align = mp->m_swidth;
186 		else if (mp->m_dalign)
187 			align = mp->m_dalign;
188 
189 		if (align && XFS_ISIZE(ip) < XFS_FSB_TO_B(mp, align))
190 			align = 0;
191 	}
192 
193 	return align;
194 }
195 
196 /*
197  * Check if last_fsb is outside the last extent, and if so grow it to the next
198  * stripe unit boundary.
199  */
200 xfs_fileoff_t
xfs_iomap_eof_align_last_fsb(struct xfs_inode * ip,xfs_fileoff_t end_fsb)201 xfs_iomap_eof_align_last_fsb(
202 	struct xfs_inode	*ip,
203 	xfs_fileoff_t		end_fsb)
204 {
205 	struct xfs_ifork	*ifp = xfs_ifork_ptr(ip, XFS_DATA_FORK);
206 	xfs_extlen_t		extsz = xfs_get_extsz_hint(ip);
207 	xfs_extlen_t		align = xfs_eof_alignment(ip);
208 	struct xfs_bmbt_irec	irec;
209 	struct xfs_iext_cursor	icur;
210 
211 	ASSERT(!xfs_need_iread_extents(ifp));
212 
213 	/*
214 	 * Always round up the allocation request to the extent hint boundary.
215 	 */
216 	if (extsz) {
217 		if (align)
218 			align = roundup_64(align, extsz);
219 		else
220 			align = extsz;
221 	}
222 
223 	if (align) {
224 		xfs_fileoff_t	aligned_end_fsb = roundup_64(end_fsb, align);
225 
226 		xfs_iext_last(ifp, &icur);
227 		if (!xfs_iext_get_extent(ifp, &icur, &irec) ||
228 		    aligned_end_fsb >= irec.br_startoff + irec.br_blockcount)
229 			return aligned_end_fsb;
230 	}
231 
232 	return end_fsb;
233 }
234 
235 int
xfs_iomap_write_direct(struct xfs_inode * ip,xfs_fileoff_t offset_fsb,xfs_fileoff_t count_fsb,unsigned int flags,struct xfs_bmbt_irec * imap,u64 * seq)236 xfs_iomap_write_direct(
237 	struct xfs_inode	*ip,
238 	xfs_fileoff_t		offset_fsb,
239 	xfs_fileoff_t		count_fsb,
240 	unsigned int		flags,
241 	struct xfs_bmbt_irec	*imap,
242 	u64			*seq)
243 {
244 	struct xfs_mount	*mp = ip->i_mount;
245 	struct xfs_trans	*tp;
246 	xfs_filblks_t		resaligned;
247 	int			nimaps;
248 	unsigned int		dblocks, rblocks;
249 	bool			force = false;
250 	int			error;
251 	int			bmapi_flags = XFS_BMAPI_PREALLOC;
252 	int			nr_exts = XFS_IEXT_ADD_NOSPLIT_CNT;
253 
254 	ASSERT(count_fsb > 0);
255 
256 	resaligned = xfs_aligned_fsb_count(offset_fsb, count_fsb,
257 					   xfs_get_extsz_hint(ip));
258 	if (unlikely(XFS_IS_REALTIME_INODE(ip))) {
259 		dblocks = XFS_DIOSTRAT_SPACE_RES(mp, 0);
260 		rblocks = resaligned;
261 	} else {
262 		dblocks = XFS_DIOSTRAT_SPACE_RES(mp, resaligned);
263 		rblocks = 0;
264 	}
265 
266 	error = xfs_qm_dqattach(ip);
267 	if (error)
268 		return error;
269 
270 	/*
271 	 * For DAX, we do not allocate unwritten extents, but instead we zero
272 	 * the block before we commit the transaction.  Ideally we'd like to do
273 	 * this outside the transaction context, but if we commit and then crash
274 	 * we may not have zeroed the blocks and this will be exposed on
275 	 * recovery of the allocation. Hence we must zero before commit.
276 	 *
277 	 * Further, if we are mapping unwritten extents here, we need to zero
278 	 * and convert them to written so that we don't need an unwritten extent
279 	 * callback for DAX. This also means that we need to be able to dip into
280 	 * the reserve block pool for bmbt block allocation if there is no space
281 	 * left but we need to do unwritten extent conversion.
282 	 */
283 	if (flags & IOMAP_DAX) {
284 		bmapi_flags = XFS_BMAPI_CONVERT | XFS_BMAPI_ZERO;
285 		if (imap->br_state == XFS_EXT_UNWRITTEN) {
286 			force = true;
287 			nr_exts = XFS_IEXT_WRITE_UNWRITTEN_CNT;
288 			dblocks = XFS_DIOSTRAT_SPACE_RES(mp, 0) << 1;
289 		}
290 	}
291 
292 	error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write, dblocks,
293 			rblocks, force, &tp);
294 	if (error)
295 		return error;
296 
297 	error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK, nr_exts);
298 	if (error == -EFBIG)
299 		error = xfs_iext_count_upgrade(tp, ip, nr_exts);
300 	if (error)
301 		goto out_trans_cancel;
302 
303 	/*
304 	 * From this point onwards we overwrite the imap pointer that the
305 	 * caller gave to us.
306 	 */
307 	nimaps = 1;
308 	error = xfs_bmapi_write(tp, ip, offset_fsb, count_fsb, bmapi_flags, 0,
309 				imap, &nimaps);
310 	if (error)
311 		goto out_trans_cancel;
312 
313 	/*
314 	 * Complete the transaction
315 	 */
316 	error = xfs_trans_commit(tp);
317 	if (error)
318 		goto out_unlock;
319 
320 	/*
321 	 * Copy any maps to caller's array and return any error.
322 	 */
323 	if (nimaps == 0) {
324 		error = -ENOSPC;
325 		goto out_unlock;
326 	}
327 
328 	if (unlikely(!xfs_valid_startblock(ip, imap->br_startblock)))
329 		error = xfs_alert_fsblock_zero(ip, imap);
330 
331 out_unlock:
332 	*seq = xfs_iomap_inode_sequence(ip, 0);
333 	xfs_iunlock(ip, XFS_ILOCK_EXCL);
334 	return error;
335 
336 out_trans_cancel:
337 	xfs_trans_cancel(tp);
338 	goto out_unlock;
339 }
340 
341 STATIC bool
xfs_quota_need_throttle(struct xfs_inode * ip,xfs_dqtype_t type,xfs_fsblock_t alloc_blocks)342 xfs_quota_need_throttle(
343 	struct xfs_inode	*ip,
344 	xfs_dqtype_t		type,
345 	xfs_fsblock_t		alloc_blocks)
346 {
347 	struct xfs_dquot	*dq = xfs_inode_dquot(ip, type);
348 
349 	if (!dq || !xfs_this_quota_on(ip->i_mount, type))
350 		return false;
351 
352 	/* no hi watermark, no throttle */
353 	if (!dq->q_prealloc_hi_wmark)
354 		return false;
355 
356 	/* under the lo watermark, no throttle */
357 	if (dq->q_blk.reserved + alloc_blocks < dq->q_prealloc_lo_wmark)
358 		return false;
359 
360 	return true;
361 }
362 
363 STATIC void
xfs_quota_calc_throttle(struct xfs_inode * ip,xfs_dqtype_t type,xfs_fsblock_t * qblocks,int * qshift,int64_t * qfreesp)364 xfs_quota_calc_throttle(
365 	struct xfs_inode	*ip,
366 	xfs_dqtype_t		type,
367 	xfs_fsblock_t		*qblocks,
368 	int			*qshift,
369 	int64_t			*qfreesp)
370 {
371 	struct xfs_dquot	*dq = xfs_inode_dquot(ip, type);
372 	int64_t			freesp;
373 	int			shift = 0;
374 
375 	/* no dq, or over hi wmark, squash the prealloc completely */
376 	if (!dq || dq->q_blk.reserved >= dq->q_prealloc_hi_wmark) {
377 		*qblocks = 0;
378 		*qfreesp = 0;
379 		return;
380 	}
381 
382 	freesp = dq->q_prealloc_hi_wmark - dq->q_blk.reserved;
383 	if (freesp < dq->q_low_space[XFS_QLOWSP_5_PCNT]) {
384 		shift = 2;
385 		if (freesp < dq->q_low_space[XFS_QLOWSP_3_PCNT])
386 			shift += 2;
387 		if (freesp < dq->q_low_space[XFS_QLOWSP_1_PCNT])
388 			shift += 2;
389 	}
390 
391 	if (freesp < *qfreesp)
392 		*qfreesp = freesp;
393 
394 	/* only overwrite the throttle values if we are more aggressive */
395 	if ((freesp >> shift) < (*qblocks >> *qshift)) {
396 		*qblocks = freesp;
397 		*qshift = shift;
398 	}
399 }
400 
401 /*
402  * If we don't have a user specified preallocation size, dynamically increase
403  * the preallocation size as the size of the file grows.  Cap the maximum size
404  * at a single extent or less if the filesystem is near full. The closer the
405  * filesystem is to being full, the smaller the maximum preallocation.
406  */
407 STATIC xfs_fsblock_t
xfs_iomap_prealloc_size(struct xfs_inode * ip,int whichfork,loff_t offset,loff_t count,struct xfs_iext_cursor * icur)408 xfs_iomap_prealloc_size(
409 	struct xfs_inode	*ip,
410 	int			whichfork,
411 	loff_t			offset,
412 	loff_t			count,
413 	struct xfs_iext_cursor	*icur)
414 {
415 	struct xfs_iext_cursor	ncur = *icur;
416 	struct xfs_bmbt_irec	prev, got;
417 	struct xfs_mount	*mp = ip->i_mount;
418 	struct xfs_ifork	*ifp = xfs_ifork_ptr(ip, whichfork);
419 	xfs_fileoff_t		offset_fsb = XFS_B_TO_FSBT(mp, offset);
420 	int64_t			freesp;
421 	xfs_fsblock_t		qblocks;
422 	xfs_fsblock_t		alloc_blocks = 0;
423 	xfs_extlen_t		plen;
424 	int			shift = 0;
425 	int			qshift = 0;
426 
427 	/*
428 	 * As an exception we don't do any preallocation at all if the file is
429 	 * smaller than the minimum preallocation and we are using the default
430 	 * dynamic preallocation scheme, as it is likely this is the only write
431 	 * to the file that is going to be done.
432 	 */
433 	if (XFS_ISIZE(ip) < XFS_FSB_TO_B(mp, mp->m_allocsize_blocks))
434 		return 0;
435 
436 	/*
437 	 * Use the minimum preallocation size for small files or if we are
438 	 * writing right after a hole.
439 	 */
440 	if (XFS_ISIZE(ip) < XFS_FSB_TO_B(mp, mp->m_dalign) ||
441 	    !xfs_iext_prev_extent(ifp, &ncur, &prev) ||
442 	    prev.br_startoff + prev.br_blockcount < offset_fsb)
443 		return mp->m_allocsize_blocks;
444 
445 	/*
446 	 * Take the size of the preceding data extents as the basis for the
447 	 * preallocation size. Note that we don't care if the previous extents
448 	 * are written or not.
449 	 */
450 	plen = prev.br_blockcount;
451 	while (xfs_iext_prev_extent(ifp, &ncur, &got)) {
452 		if (plen > XFS_MAX_BMBT_EXTLEN / 2 ||
453 		    isnullstartblock(got.br_startblock) ||
454 		    got.br_startoff + got.br_blockcount != prev.br_startoff ||
455 		    got.br_startblock + got.br_blockcount != prev.br_startblock)
456 			break;
457 		plen += got.br_blockcount;
458 		prev = got;
459 	}
460 
461 	/*
462 	 * If the size of the extents is greater than half the maximum extent
463 	 * length, then use the current offset as the basis.  This ensures that
464 	 * for large files the preallocation size always extends to
465 	 * XFS_BMBT_MAX_EXTLEN rather than falling short due to things like stripe
466 	 * unit/width alignment of real extents.
467 	 */
468 	alloc_blocks = plen * 2;
469 	if (alloc_blocks > XFS_MAX_BMBT_EXTLEN)
470 		alloc_blocks = XFS_B_TO_FSB(mp, offset);
471 	qblocks = alloc_blocks;
472 
473 	/*
474 	 * XFS_BMBT_MAX_EXTLEN is not a power of two value but we round the prealloc
475 	 * down to the nearest power of two value after throttling. To prevent
476 	 * the round down from unconditionally reducing the maximum supported
477 	 * prealloc size, we round up first, apply appropriate throttling, round
478 	 * down and cap the value to XFS_BMBT_MAX_EXTLEN.
479 	 */
480 	alloc_blocks = XFS_FILEOFF_MIN(roundup_pow_of_two(XFS_MAX_BMBT_EXTLEN),
481 				       alloc_blocks);
482 
483 	freesp = percpu_counter_read_positive(&mp->m_fdblocks);
484 	if (freesp < mp->m_low_space[XFS_LOWSP_5_PCNT]) {
485 		shift = 2;
486 		if (freesp < mp->m_low_space[XFS_LOWSP_4_PCNT])
487 			shift++;
488 		if (freesp < mp->m_low_space[XFS_LOWSP_3_PCNT])
489 			shift++;
490 		if (freesp < mp->m_low_space[XFS_LOWSP_2_PCNT])
491 			shift++;
492 		if (freesp < mp->m_low_space[XFS_LOWSP_1_PCNT])
493 			shift++;
494 	}
495 
496 	/*
497 	 * Check each quota to cap the prealloc size, provide a shift value to
498 	 * throttle with and adjust amount of available space.
499 	 */
500 	if (xfs_quota_need_throttle(ip, XFS_DQTYPE_USER, alloc_blocks))
501 		xfs_quota_calc_throttle(ip, XFS_DQTYPE_USER, &qblocks, &qshift,
502 					&freesp);
503 	if (xfs_quota_need_throttle(ip, XFS_DQTYPE_GROUP, alloc_blocks))
504 		xfs_quota_calc_throttle(ip, XFS_DQTYPE_GROUP, &qblocks, &qshift,
505 					&freesp);
506 	if (xfs_quota_need_throttle(ip, XFS_DQTYPE_PROJ, alloc_blocks))
507 		xfs_quota_calc_throttle(ip, XFS_DQTYPE_PROJ, &qblocks, &qshift,
508 					&freesp);
509 
510 	/*
511 	 * The final prealloc size is set to the minimum of free space available
512 	 * in each of the quotas and the overall filesystem.
513 	 *
514 	 * The shift throttle value is set to the maximum value as determined by
515 	 * the global low free space values and per-quota low free space values.
516 	 */
517 	alloc_blocks = min(alloc_blocks, qblocks);
518 	shift = max(shift, qshift);
519 
520 	if (shift)
521 		alloc_blocks >>= shift;
522 	/*
523 	 * rounddown_pow_of_two() returns an undefined result if we pass in
524 	 * alloc_blocks = 0.
525 	 */
526 	if (alloc_blocks)
527 		alloc_blocks = rounddown_pow_of_two(alloc_blocks);
528 	if (alloc_blocks > XFS_MAX_BMBT_EXTLEN)
529 		alloc_blocks = XFS_MAX_BMBT_EXTLEN;
530 
531 	/*
532 	 * If we are still trying to allocate more space than is
533 	 * available, squash the prealloc hard. This can happen if we
534 	 * have a large file on a small filesystem and the above
535 	 * lowspace thresholds are smaller than XFS_BMBT_MAX_EXTLEN.
536 	 */
537 	while (alloc_blocks && alloc_blocks >= freesp)
538 		alloc_blocks >>= 4;
539 	if (alloc_blocks < mp->m_allocsize_blocks)
540 		alloc_blocks = mp->m_allocsize_blocks;
541 	trace_xfs_iomap_prealloc_size(ip, alloc_blocks, shift,
542 				      mp->m_allocsize_blocks);
543 	return alloc_blocks;
544 }
545 
546 int
xfs_iomap_write_unwritten(xfs_inode_t * ip,xfs_off_t offset,xfs_off_t count,bool update_isize)547 xfs_iomap_write_unwritten(
548 	xfs_inode_t	*ip,
549 	xfs_off_t	offset,
550 	xfs_off_t	count,
551 	bool		update_isize)
552 {
553 	xfs_mount_t	*mp = ip->i_mount;
554 	xfs_fileoff_t	offset_fsb;
555 	xfs_filblks_t	count_fsb;
556 	xfs_filblks_t	numblks_fsb;
557 	int		nimaps;
558 	xfs_trans_t	*tp;
559 	xfs_bmbt_irec_t imap;
560 	struct inode	*inode = VFS_I(ip);
561 	xfs_fsize_t	i_size;
562 	uint		resblks;
563 	int		error;
564 
565 	trace_xfs_unwritten_convert(ip, offset, count);
566 
567 	offset_fsb = XFS_B_TO_FSBT(mp, offset);
568 	count_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + count);
569 	count_fsb = (xfs_filblks_t)(count_fsb - offset_fsb);
570 
571 	/*
572 	 * Reserve enough blocks in this transaction for two complete extent
573 	 * btree splits.  We may be converting the middle part of an unwritten
574 	 * extent and in this case we will insert two new extents in the btree
575 	 * each of which could cause a full split.
576 	 *
577 	 * This reservation amount will be used in the first call to
578 	 * xfs_bmbt_split() to select an AG with enough space to satisfy the
579 	 * rest of the operation.
580 	 */
581 	resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0) << 1;
582 
583 	/* Attach dquots so that bmbt splits are accounted correctly. */
584 	error = xfs_qm_dqattach(ip);
585 	if (error)
586 		return error;
587 
588 	do {
589 		/*
590 		 * Set up a transaction to convert the range of extents
591 		 * from unwritten to real. Do allocations in a loop until
592 		 * we have covered the range passed in.
593 		 *
594 		 * Note that we can't risk to recursing back into the filesystem
595 		 * here as we might be asked to write out the same inode that we
596 		 * complete here and might deadlock on the iolock.
597 		 */
598 		error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write, resblks,
599 				0, true, &tp);
600 		if (error)
601 			return error;
602 
603 		error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK,
604 				XFS_IEXT_WRITE_UNWRITTEN_CNT);
605 		if (error == -EFBIG)
606 			error = xfs_iext_count_upgrade(tp, ip,
607 					XFS_IEXT_WRITE_UNWRITTEN_CNT);
608 		if (error)
609 			goto error_on_bmapi_transaction;
610 
611 		/*
612 		 * Modify the unwritten extent state of the buffer.
613 		 */
614 		nimaps = 1;
615 		error = xfs_bmapi_write(tp, ip, offset_fsb, count_fsb,
616 					XFS_BMAPI_CONVERT, resblks, &imap,
617 					&nimaps);
618 		if (error)
619 			goto error_on_bmapi_transaction;
620 
621 		/*
622 		 * Log the updated inode size as we go.  We have to be careful
623 		 * to only log it up to the actual write offset if it is
624 		 * halfway into a block.
625 		 */
626 		i_size = XFS_FSB_TO_B(mp, offset_fsb + count_fsb);
627 		if (i_size > offset + count)
628 			i_size = offset + count;
629 		if (update_isize && i_size > i_size_read(inode))
630 			i_size_write(inode, i_size);
631 		i_size = xfs_new_eof(ip, i_size);
632 		if (i_size) {
633 			ip->i_disk_size = i_size;
634 			xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
635 		}
636 
637 		error = xfs_trans_commit(tp);
638 		xfs_iunlock(ip, XFS_ILOCK_EXCL);
639 		if (error)
640 			return error;
641 
642 		if (unlikely(!xfs_valid_startblock(ip, imap.br_startblock)))
643 			return xfs_alert_fsblock_zero(ip, &imap);
644 
645 		if ((numblks_fsb = imap.br_blockcount) == 0) {
646 			/*
647 			 * The numblks_fsb value should always get
648 			 * smaller, otherwise the loop is stuck.
649 			 */
650 			ASSERT(imap.br_blockcount);
651 			break;
652 		}
653 		offset_fsb += numblks_fsb;
654 		count_fsb -= numblks_fsb;
655 	} while (count_fsb > 0);
656 
657 	return 0;
658 
659 error_on_bmapi_transaction:
660 	xfs_trans_cancel(tp);
661 	xfs_iunlock(ip, XFS_ILOCK_EXCL);
662 	return error;
663 }
664 
665 static inline bool
imap_needs_alloc(struct inode * inode,unsigned flags,struct xfs_bmbt_irec * imap,int nimaps)666 imap_needs_alloc(
667 	struct inode		*inode,
668 	unsigned		flags,
669 	struct xfs_bmbt_irec	*imap,
670 	int			nimaps)
671 {
672 	/* don't allocate blocks when just zeroing */
673 	if (flags & IOMAP_ZERO)
674 		return false;
675 	if (!nimaps ||
676 	    imap->br_startblock == HOLESTARTBLOCK ||
677 	    imap->br_startblock == DELAYSTARTBLOCK)
678 		return true;
679 	/* we convert unwritten extents before copying the data for DAX */
680 	if ((flags & IOMAP_DAX) && imap->br_state == XFS_EXT_UNWRITTEN)
681 		return true;
682 	return false;
683 }
684 
685 static inline bool
imap_needs_cow(struct xfs_inode * ip,unsigned int flags,struct xfs_bmbt_irec * imap,int nimaps)686 imap_needs_cow(
687 	struct xfs_inode	*ip,
688 	unsigned int		flags,
689 	struct xfs_bmbt_irec	*imap,
690 	int			nimaps)
691 {
692 	if (!xfs_is_cow_inode(ip))
693 		return false;
694 
695 	/* when zeroing we don't have to COW holes or unwritten extents */
696 	if (flags & IOMAP_ZERO) {
697 		if (!nimaps ||
698 		    imap->br_startblock == HOLESTARTBLOCK ||
699 		    imap->br_state == XFS_EXT_UNWRITTEN)
700 			return false;
701 	}
702 
703 	return true;
704 }
705 
706 static int
xfs_ilock_for_iomap(struct xfs_inode * ip,unsigned flags,unsigned * lockmode)707 xfs_ilock_for_iomap(
708 	struct xfs_inode	*ip,
709 	unsigned		flags,
710 	unsigned		*lockmode)
711 {
712 	unsigned int		mode = *lockmode;
713 	bool			is_write = flags & (IOMAP_WRITE | IOMAP_ZERO);
714 
715 	/*
716 	 * COW writes may allocate delalloc space or convert unwritten COW
717 	 * extents, so we need to make sure to take the lock exclusively here.
718 	 */
719 	if (xfs_is_cow_inode(ip) && is_write)
720 		mode = XFS_ILOCK_EXCL;
721 
722 	/*
723 	 * Extents not yet cached requires exclusive access, don't block.  This
724 	 * is an opencoded xfs_ilock_data_map_shared() call but with
725 	 * non-blocking behaviour.
726 	 */
727 	if (xfs_need_iread_extents(&ip->i_df)) {
728 		if (flags & IOMAP_NOWAIT)
729 			return -EAGAIN;
730 		mode = XFS_ILOCK_EXCL;
731 	}
732 
733 relock:
734 	if (flags & IOMAP_NOWAIT) {
735 		if (!xfs_ilock_nowait(ip, mode))
736 			return -EAGAIN;
737 	} else {
738 		xfs_ilock(ip, mode);
739 	}
740 
741 	/*
742 	 * The reflink iflag could have changed since the earlier unlocked
743 	 * check, so if we got ILOCK_SHARED for a write and but we're now a
744 	 * reflink inode we have to switch to ILOCK_EXCL and relock.
745 	 */
746 	if (mode == XFS_ILOCK_SHARED && is_write && xfs_is_cow_inode(ip)) {
747 		xfs_iunlock(ip, mode);
748 		mode = XFS_ILOCK_EXCL;
749 		goto relock;
750 	}
751 
752 	*lockmode = mode;
753 	return 0;
754 }
755 
756 /*
757  * Check that the imap we are going to return to the caller spans the entire
758  * range that the caller requested for the IO.
759  */
760 static bool
imap_spans_range(struct xfs_bmbt_irec * imap,xfs_fileoff_t offset_fsb,xfs_fileoff_t end_fsb)761 imap_spans_range(
762 	struct xfs_bmbt_irec	*imap,
763 	xfs_fileoff_t		offset_fsb,
764 	xfs_fileoff_t		end_fsb)
765 {
766 	if (imap->br_startoff > offset_fsb)
767 		return false;
768 	if (imap->br_startoff + imap->br_blockcount < end_fsb)
769 		return false;
770 	return true;
771 }
772 
773 static int
xfs_direct_write_iomap_begin(struct inode * inode,loff_t offset,loff_t length,unsigned flags,struct iomap * iomap,struct iomap * srcmap)774 xfs_direct_write_iomap_begin(
775 	struct inode		*inode,
776 	loff_t			offset,
777 	loff_t			length,
778 	unsigned		flags,
779 	struct iomap		*iomap,
780 	struct iomap		*srcmap)
781 {
782 	struct xfs_inode	*ip = XFS_I(inode);
783 	struct xfs_mount	*mp = ip->i_mount;
784 	struct xfs_bmbt_irec	imap, cmap;
785 	xfs_fileoff_t		offset_fsb = XFS_B_TO_FSBT(mp, offset);
786 	xfs_fileoff_t		end_fsb = xfs_iomap_end_fsb(mp, offset, length);
787 	int			nimaps = 1, error = 0;
788 	bool			shared = false;
789 	u16			iomap_flags = 0;
790 	unsigned int		lockmode = XFS_ILOCK_SHARED;
791 	u64			seq;
792 
793 	ASSERT(flags & (IOMAP_WRITE | IOMAP_ZERO));
794 
795 	if (xfs_is_shutdown(mp))
796 		return -EIO;
797 
798 	/*
799 	 * Writes that span EOF might trigger an IO size update on completion,
800 	 * so consider them to be dirty for the purposes of O_DSYNC even if
801 	 * there is no other metadata changes pending or have been made here.
802 	 */
803 	if (offset + length > i_size_read(inode))
804 		iomap_flags |= IOMAP_F_DIRTY;
805 
806 	error = xfs_ilock_for_iomap(ip, flags, &lockmode);
807 	if (error)
808 		return error;
809 
810 	error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap,
811 			       &nimaps, 0);
812 	if (error)
813 		goto out_unlock;
814 
815 	if (imap_needs_cow(ip, flags, &imap, nimaps)) {
816 		error = -EAGAIN;
817 		if (flags & IOMAP_NOWAIT)
818 			goto out_unlock;
819 
820 		/* may drop and re-acquire the ilock */
821 		error = xfs_reflink_allocate_cow(ip, &imap, &cmap, &shared,
822 				&lockmode,
823 				(flags & IOMAP_DIRECT) || IS_DAX(inode));
824 		if (error)
825 			goto out_unlock;
826 		if (shared)
827 			goto out_found_cow;
828 		end_fsb = imap.br_startoff + imap.br_blockcount;
829 		length = XFS_FSB_TO_B(mp, end_fsb) - offset;
830 	}
831 
832 	if (imap_needs_alloc(inode, flags, &imap, nimaps))
833 		goto allocate_blocks;
834 
835 	/*
836 	 * NOWAIT and OVERWRITE I/O needs to span the entire requested I/O with
837 	 * a single map so that we avoid partial IO failures due to the rest of
838 	 * the I/O range not covered by this map triggering an EAGAIN condition
839 	 * when it is subsequently mapped and aborting the I/O.
840 	 */
841 	if (flags & (IOMAP_NOWAIT | IOMAP_OVERWRITE_ONLY)) {
842 		error = -EAGAIN;
843 		if (!imap_spans_range(&imap, offset_fsb, end_fsb))
844 			goto out_unlock;
845 	}
846 
847 	/*
848 	 * For overwrite only I/O, we cannot convert unwritten extents without
849 	 * requiring sub-block zeroing.  This can only be done under an
850 	 * exclusive IOLOCK, hence return -EAGAIN if this is not a written
851 	 * extent to tell the caller to try again.
852 	 */
853 	if (flags & IOMAP_OVERWRITE_ONLY) {
854 		error = -EAGAIN;
855 		if (imap.br_state != XFS_EXT_NORM &&
856 	            ((offset | length) & mp->m_blockmask))
857 			goto out_unlock;
858 	}
859 
860 	seq = xfs_iomap_inode_sequence(ip, iomap_flags);
861 	xfs_iunlock(ip, lockmode);
862 	trace_xfs_iomap_found(ip, offset, length, XFS_DATA_FORK, &imap);
863 	return xfs_bmbt_to_iomap(ip, iomap, &imap, flags, iomap_flags, seq);
864 
865 allocate_blocks:
866 	error = -EAGAIN;
867 	if (flags & (IOMAP_NOWAIT | IOMAP_OVERWRITE_ONLY))
868 		goto out_unlock;
869 
870 	/*
871 	 * We cap the maximum length we map to a sane size  to keep the chunks
872 	 * of work done where somewhat symmetric with the work writeback does.
873 	 * This is a completely arbitrary number pulled out of thin air as a
874 	 * best guess for initial testing.
875 	 *
876 	 * Note that the values needs to be less than 32-bits wide until the
877 	 * lower level functions are updated.
878 	 */
879 	length = min_t(loff_t, length, 1024 * PAGE_SIZE);
880 	end_fsb = xfs_iomap_end_fsb(mp, offset, length);
881 
882 	if (offset + length > XFS_ISIZE(ip))
883 		end_fsb = xfs_iomap_eof_align_last_fsb(ip, end_fsb);
884 	else if (nimaps && imap.br_startblock == HOLESTARTBLOCK)
885 		end_fsb = min(end_fsb, imap.br_startoff + imap.br_blockcount);
886 	xfs_iunlock(ip, lockmode);
887 
888 	error = xfs_iomap_write_direct(ip, offset_fsb, end_fsb - offset_fsb,
889 			flags, &imap, &seq);
890 	if (error)
891 		return error;
892 
893 	trace_xfs_iomap_alloc(ip, offset, length, XFS_DATA_FORK, &imap);
894 	return xfs_bmbt_to_iomap(ip, iomap, &imap, flags,
895 				 iomap_flags | IOMAP_F_NEW, seq);
896 
897 out_found_cow:
898 	length = XFS_FSB_TO_B(mp, cmap.br_startoff + cmap.br_blockcount);
899 	trace_xfs_iomap_found(ip, offset, length - offset, XFS_COW_FORK, &cmap);
900 	if (imap.br_startblock != HOLESTARTBLOCK) {
901 		seq = xfs_iomap_inode_sequence(ip, 0);
902 		error = xfs_bmbt_to_iomap(ip, srcmap, &imap, flags, 0, seq);
903 		if (error)
904 			goto out_unlock;
905 	}
906 	seq = xfs_iomap_inode_sequence(ip, IOMAP_F_SHARED);
907 	xfs_iunlock(ip, lockmode);
908 	return xfs_bmbt_to_iomap(ip, iomap, &cmap, flags, IOMAP_F_SHARED, seq);
909 
910 out_unlock:
911 	if (lockmode)
912 		xfs_iunlock(ip, lockmode);
913 	return error;
914 }
915 
916 const struct iomap_ops xfs_direct_write_iomap_ops = {
917 	.iomap_begin		= xfs_direct_write_iomap_begin,
918 };
919 
920 static int
xfs_dax_write_iomap_end(struct inode * inode,loff_t pos,loff_t length,ssize_t written,unsigned flags,struct iomap * iomap)921 xfs_dax_write_iomap_end(
922 	struct inode		*inode,
923 	loff_t			pos,
924 	loff_t			length,
925 	ssize_t			written,
926 	unsigned		flags,
927 	struct iomap		*iomap)
928 {
929 	struct xfs_inode	*ip = XFS_I(inode);
930 
931 	if (!xfs_is_cow_inode(ip))
932 		return 0;
933 
934 	if (!written) {
935 		xfs_reflink_cancel_cow_range(ip, pos, length, true);
936 		return 0;
937 	}
938 
939 	return xfs_reflink_end_cow(ip, pos, written);
940 }
941 
942 const struct iomap_ops xfs_dax_write_iomap_ops = {
943 	.iomap_begin	= xfs_direct_write_iomap_begin,
944 	.iomap_end	= xfs_dax_write_iomap_end,
945 };
946 
947 static int
xfs_buffered_write_iomap_begin(struct inode * inode,loff_t offset,loff_t count,unsigned flags,struct iomap * iomap,struct iomap * srcmap)948 xfs_buffered_write_iomap_begin(
949 	struct inode		*inode,
950 	loff_t			offset,
951 	loff_t			count,
952 	unsigned		flags,
953 	struct iomap		*iomap,
954 	struct iomap		*srcmap)
955 {
956 	struct xfs_inode	*ip = XFS_I(inode);
957 	struct xfs_mount	*mp = ip->i_mount;
958 	xfs_fileoff_t		offset_fsb = XFS_B_TO_FSBT(mp, offset);
959 	xfs_fileoff_t		end_fsb = xfs_iomap_end_fsb(mp, offset, count);
960 	struct xfs_bmbt_irec	imap, cmap;
961 	struct xfs_iext_cursor	icur, ccur;
962 	xfs_fsblock_t		prealloc_blocks = 0;
963 	bool			eof = false, cow_eof = false, shared = false;
964 	int			allocfork = XFS_DATA_FORK;
965 	int			error = 0;
966 	unsigned int		lockmode = XFS_ILOCK_EXCL;
967 	u64			seq;
968 
969 	if (xfs_is_shutdown(mp))
970 		return -EIO;
971 
972 	/* we can't use delayed allocations when using extent size hints */
973 	if (xfs_get_extsz_hint(ip))
974 		return xfs_direct_write_iomap_begin(inode, offset, count,
975 				flags, iomap, srcmap);
976 
977 	ASSERT(!XFS_IS_REALTIME_INODE(ip));
978 
979 	error = xfs_qm_dqattach(ip);
980 	if (error)
981 		return error;
982 
983 	error = xfs_ilock_for_iomap(ip, flags, &lockmode);
984 	if (error)
985 		return error;
986 
987 	if (XFS_IS_CORRUPT(mp, !xfs_ifork_has_extents(&ip->i_df)) ||
988 	    XFS_TEST_ERROR(false, mp, XFS_ERRTAG_BMAPIFORMAT)) {
989 		error = -EFSCORRUPTED;
990 		goto out_unlock;
991 	}
992 
993 	XFS_STATS_INC(mp, xs_blk_mapw);
994 
995 	error = xfs_iread_extents(NULL, ip, XFS_DATA_FORK);
996 	if (error)
997 		goto out_unlock;
998 
999 	/*
1000 	 * Search the data fork first to look up our source mapping.  We
1001 	 * always need the data fork map, as we have to return it to the
1002 	 * iomap code so that the higher level write code can read data in to
1003 	 * perform read-modify-write cycles for unaligned writes.
1004 	 */
1005 	eof = !xfs_iext_lookup_extent(ip, &ip->i_df, offset_fsb, &icur, &imap);
1006 	if (eof)
1007 		imap.br_startoff = end_fsb; /* fake hole until the end */
1008 
1009 	/* We never need to allocate blocks for zeroing or unsharing a hole. */
1010 	if ((flags & (IOMAP_UNSHARE | IOMAP_ZERO)) &&
1011 	    imap.br_startoff > offset_fsb) {
1012 		xfs_hole_to_iomap(ip, iomap, offset_fsb, imap.br_startoff);
1013 		goto out_unlock;
1014 	}
1015 
1016 	/*
1017 	 * Search the COW fork extent list even if we did not find a data fork
1018 	 * extent.  This serves two purposes: first this implements the
1019 	 * speculative preallocation using cowextsize, so that we also unshare
1020 	 * block adjacent to shared blocks instead of just the shared blocks
1021 	 * themselves.  Second the lookup in the extent list is generally faster
1022 	 * than going out to the shared extent tree.
1023 	 */
1024 	if (xfs_is_cow_inode(ip)) {
1025 		if (!ip->i_cowfp) {
1026 			ASSERT(!xfs_is_reflink_inode(ip));
1027 			xfs_ifork_init_cow(ip);
1028 		}
1029 		cow_eof = !xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb,
1030 				&ccur, &cmap);
1031 		if (!cow_eof && cmap.br_startoff <= offset_fsb) {
1032 			trace_xfs_reflink_cow_found(ip, &cmap);
1033 			goto found_cow;
1034 		}
1035 	}
1036 
1037 	if (imap.br_startoff <= offset_fsb) {
1038 		/*
1039 		 * For reflink files we may need a delalloc reservation when
1040 		 * overwriting shared extents.   This includes zeroing of
1041 		 * existing extents that contain data.
1042 		 */
1043 		if (!xfs_is_cow_inode(ip) ||
1044 		    ((flags & IOMAP_ZERO) && imap.br_state != XFS_EXT_NORM)) {
1045 			trace_xfs_iomap_found(ip, offset, count, XFS_DATA_FORK,
1046 					&imap);
1047 			goto found_imap;
1048 		}
1049 
1050 		xfs_trim_extent(&imap, offset_fsb, end_fsb - offset_fsb);
1051 
1052 		/* Trim the mapping to the nearest shared extent boundary. */
1053 		error = xfs_bmap_trim_cow(ip, &imap, &shared);
1054 		if (error)
1055 			goto out_unlock;
1056 
1057 		/* Not shared?  Just report the (potentially capped) extent. */
1058 		if (!shared) {
1059 			trace_xfs_iomap_found(ip, offset, count, XFS_DATA_FORK,
1060 					&imap);
1061 			goto found_imap;
1062 		}
1063 
1064 		/*
1065 		 * Fork all the shared blocks from our write offset until the
1066 		 * end of the extent.
1067 		 */
1068 		allocfork = XFS_COW_FORK;
1069 		end_fsb = imap.br_startoff + imap.br_blockcount;
1070 	} else {
1071 		/*
1072 		 * We cap the maximum length we map here to MAX_WRITEBACK_PAGES
1073 		 * pages to keep the chunks of work done where somewhat
1074 		 * symmetric with the work writeback does.  This is a completely
1075 		 * arbitrary number pulled out of thin air.
1076 		 *
1077 		 * Note that the values needs to be less than 32-bits wide until
1078 		 * the lower level functions are updated.
1079 		 */
1080 		count = min_t(loff_t, count, 1024 * PAGE_SIZE);
1081 		end_fsb = xfs_iomap_end_fsb(mp, offset, count);
1082 
1083 		if (xfs_is_always_cow_inode(ip))
1084 			allocfork = XFS_COW_FORK;
1085 	}
1086 
1087 	if (eof && offset + count > XFS_ISIZE(ip)) {
1088 		/*
1089 		 * Determine the initial size of the preallocation.
1090 		 * We clean up any extra preallocation when the file is closed.
1091 		 */
1092 		if (xfs_has_allocsize(mp))
1093 			prealloc_blocks = mp->m_allocsize_blocks;
1094 		else if (allocfork == XFS_DATA_FORK)
1095 			prealloc_blocks = xfs_iomap_prealloc_size(ip, allocfork,
1096 						offset, count, &icur);
1097 		else
1098 			prealloc_blocks = xfs_iomap_prealloc_size(ip, allocfork,
1099 						offset, count, &ccur);
1100 		if (prealloc_blocks) {
1101 			xfs_extlen_t	align;
1102 			xfs_off_t	end_offset;
1103 			xfs_fileoff_t	p_end_fsb;
1104 
1105 			end_offset = XFS_ALLOC_ALIGN(mp, offset + count - 1);
1106 			p_end_fsb = XFS_B_TO_FSBT(mp, end_offset) +
1107 					prealloc_blocks;
1108 
1109 			align = xfs_eof_alignment(ip);
1110 			if (align)
1111 				p_end_fsb = roundup_64(p_end_fsb, align);
1112 
1113 			p_end_fsb = min(p_end_fsb,
1114 				XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes));
1115 			ASSERT(p_end_fsb > offset_fsb);
1116 			prealloc_blocks = p_end_fsb - end_fsb;
1117 		}
1118 	}
1119 
1120 retry:
1121 	error = xfs_bmapi_reserve_delalloc(ip, allocfork, offset_fsb,
1122 			end_fsb - offset_fsb, prealloc_blocks,
1123 			allocfork == XFS_DATA_FORK ? &imap : &cmap,
1124 			allocfork == XFS_DATA_FORK ? &icur : &ccur,
1125 			allocfork == XFS_DATA_FORK ? eof : cow_eof);
1126 	switch (error) {
1127 	case 0:
1128 		break;
1129 	case -ENOSPC:
1130 	case -EDQUOT:
1131 		/* retry without any preallocation */
1132 		trace_xfs_delalloc_enospc(ip, offset, count);
1133 		if (prealloc_blocks) {
1134 			prealloc_blocks = 0;
1135 			goto retry;
1136 		}
1137 		fallthrough;
1138 	default:
1139 		goto out_unlock;
1140 	}
1141 
1142 	if (allocfork == XFS_COW_FORK) {
1143 		trace_xfs_iomap_alloc(ip, offset, count, allocfork, &cmap);
1144 		goto found_cow;
1145 	}
1146 
1147 	/*
1148 	 * Flag newly allocated delalloc blocks with IOMAP_F_NEW so we punch
1149 	 * them out if the write happens to fail.
1150 	 */
1151 	seq = xfs_iomap_inode_sequence(ip, IOMAP_F_NEW);
1152 	xfs_iunlock(ip, XFS_ILOCK_EXCL);
1153 	trace_xfs_iomap_alloc(ip, offset, count, allocfork, &imap);
1154 	return xfs_bmbt_to_iomap(ip, iomap, &imap, flags, IOMAP_F_NEW, seq);
1155 
1156 found_imap:
1157 	seq = xfs_iomap_inode_sequence(ip, 0);
1158 	xfs_iunlock(ip, XFS_ILOCK_EXCL);
1159 	return xfs_bmbt_to_iomap(ip, iomap, &imap, flags, 0, seq);
1160 
1161 found_cow:
1162 	seq = xfs_iomap_inode_sequence(ip, 0);
1163 	if (imap.br_startoff <= offset_fsb) {
1164 		error = xfs_bmbt_to_iomap(ip, srcmap, &imap, flags, 0, seq);
1165 		if (error)
1166 			goto out_unlock;
1167 		seq = xfs_iomap_inode_sequence(ip, IOMAP_F_SHARED);
1168 		xfs_iunlock(ip, XFS_ILOCK_EXCL);
1169 		return xfs_bmbt_to_iomap(ip, iomap, &cmap, flags,
1170 					 IOMAP_F_SHARED, seq);
1171 	}
1172 
1173 	xfs_trim_extent(&cmap, offset_fsb, imap.br_startoff - offset_fsb);
1174 	xfs_iunlock(ip, XFS_ILOCK_EXCL);
1175 	return xfs_bmbt_to_iomap(ip, iomap, &cmap, flags, 0, seq);
1176 
1177 out_unlock:
1178 	xfs_iunlock(ip, XFS_ILOCK_EXCL);
1179 	return error;
1180 }
1181 
1182 static int
xfs_buffered_write_delalloc_punch(struct inode * inode,loff_t offset,loff_t length)1183 xfs_buffered_write_delalloc_punch(
1184 	struct inode		*inode,
1185 	loff_t			offset,
1186 	loff_t			length)
1187 {
1188 	return xfs_bmap_punch_delalloc_range(XFS_I(inode), offset,
1189 			offset + length);
1190 }
1191 
1192 static int
xfs_buffered_write_iomap_end(struct inode * inode,loff_t offset,loff_t length,ssize_t written,unsigned flags,struct iomap * iomap)1193 xfs_buffered_write_iomap_end(
1194 	struct inode		*inode,
1195 	loff_t			offset,
1196 	loff_t			length,
1197 	ssize_t			written,
1198 	unsigned		flags,
1199 	struct iomap		*iomap)
1200 {
1201 
1202 	struct xfs_mount	*mp = XFS_M(inode->i_sb);
1203 	int			error;
1204 
1205 	error = iomap_file_buffered_write_punch_delalloc(inode, iomap, offset,
1206 			length, written, &xfs_buffered_write_delalloc_punch);
1207 	if (error && !xfs_is_shutdown(mp)) {
1208 		xfs_alert(mp, "%s: unable to clean up ino 0x%llx",
1209 			__func__, XFS_I(inode)->i_ino);
1210 		return error;
1211 	}
1212 	return 0;
1213 }
1214 
1215 const struct iomap_ops xfs_buffered_write_iomap_ops = {
1216 	.iomap_begin		= xfs_buffered_write_iomap_begin,
1217 	.iomap_end		= xfs_buffered_write_iomap_end,
1218 };
1219 
1220 /*
1221  * iomap_page_mkwrite() will never fail in a way that requires delalloc extents
1222  * that it allocated to be revoked. Hence we do not need an .iomap_end method
1223  * for this operation.
1224  */
1225 const struct iomap_ops xfs_page_mkwrite_iomap_ops = {
1226 	.iomap_begin		= xfs_buffered_write_iomap_begin,
1227 };
1228 
1229 static int
xfs_read_iomap_begin(struct inode * inode,loff_t offset,loff_t length,unsigned flags,struct iomap * iomap,struct iomap * srcmap)1230 xfs_read_iomap_begin(
1231 	struct inode		*inode,
1232 	loff_t			offset,
1233 	loff_t			length,
1234 	unsigned		flags,
1235 	struct iomap		*iomap,
1236 	struct iomap		*srcmap)
1237 {
1238 	struct xfs_inode	*ip = XFS_I(inode);
1239 	struct xfs_mount	*mp = ip->i_mount;
1240 	struct xfs_bmbt_irec	imap;
1241 	xfs_fileoff_t		offset_fsb = XFS_B_TO_FSBT(mp, offset);
1242 	xfs_fileoff_t		end_fsb = xfs_iomap_end_fsb(mp, offset, length);
1243 	int			nimaps = 1, error = 0;
1244 	bool			shared = false;
1245 	unsigned int		lockmode = XFS_ILOCK_SHARED;
1246 	u64			seq;
1247 
1248 	ASSERT(!(flags & (IOMAP_WRITE | IOMAP_ZERO)));
1249 
1250 	if (xfs_is_shutdown(mp))
1251 		return -EIO;
1252 
1253 	error = xfs_ilock_for_iomap(ip, flags, &lockmode);
1254 	if (error)
1255 		return error;
1256 	error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap,
1257 			       &nimaps, 0);
1258 	if (!error && ((flags & IOMAP_REPORT) || IS_DAX(inode)))
1259 		error = xfs_reflink_trim_around_shared(ip, &imap, &shared);
1260 	seq = xfs_iomap_inode_sequence(ip, shared ? IOMAP_F_SHARED : 0);
1261 	xfs_iunlock(ip, lockmode);
1262 
1263 	if (error)
1264 		return error;
1265 	trace_xfs_iomap_found(ip, offset, length, XFS_DATA_FORK, &imap);
1266 	return xfs_bmbt_to_iomap(ip, iomap, &imap, flags,
1267 				 shared ? IOMAP_F_SHARED : 0, seq);
1268 }
1269 
1270 const struct iomap_ops xfs_read_iomap_ops = {
1271 	.iomap_begin		= xfs_read_iomap_begin,
1272 };
1273 
1274 static int
xfs_seek_iomap_begin(struct inode * inode,loff_t offset,loff_t length,unsigned flags,struct iomap * iomap,struct iomap * srcmap)1275 xfs_seek_iomap_begin(
1276 	struct inode		*inode,
1277 	loff_t			offset,
1278 	loff_t			length,
1279 	unsigned		flags,
1280 	struct iomap		*iomap,
1281 	struct iomap		*srcmap)
1282 {
1283 	struct xfs_inode	*ip = XFS_I(inode);
1284 	struct xfs_mount	*mp = ip->i_mount;
1285 	xfs_fileoff_t		offset_fsb = XFS_B_TO_FSBT(mp, offset);
1286 	xfs_fileoff_t		end_fsb = XFS_B_TO_FSB(mp, offset + length);
1287 	xfs_fileoff_t		cow_fsb = NULLFILEOFF, data_fsb = NULLFILEOFF;
1288 	struct xfs_iext_cursor	icur;
1289 	struct xfs_bmbt_irec	imap, cmap;
1290 	int			error = 0;
1291 	unsigned		lockmode;
1292 	u64			seq;
1293 
1294 	if (xfs_is_shutdown(mp))
1295 		return -EIO;
1296 
1297 	lockmode = xfs_ilock_data_map_shared(ip);
1298 	error = xfs_iread_extents(NULL, ip, XFS_DATA_FORK);
1299 	if (error)
1300 		goto out_unlock;
1301 
1302 	if (xfs_iext_lookup_extent(ip, &ip->i_df, offset_fsb, &icur, &imap)) {
1303 		/*
1304 		 * If we found a data extent we are done.
1305 		 */
1306 		if (imap.br_startoff <= offset_fsb)
1307 			goto done;
1308 		data_fsb = imap.br_startoff;
1309 	} else {
1310 		/*
1311 		 * Fake a hole until the end of the file.
1312 		 */
1313 		data_fsb = xfs_iomap_end_fsb(mp, offset, length);
1314 	}
1315 
1316 	/*
1317 	 * If a COW fork extent covers the hole, report it - capped to the next
1318 	 * data fork extent:
1319 	 */
1320 	if (xfs_inode_has_cow_data(ip) &&
1321 	    xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb, &icur, &cmap))
1322 		cow_fsb = cmap.br_startoff;
1323 	if (cow_fsb != NULLFILEOFF && cow_fsb <= offset_fsb) {
1324 		if (data_fsb < cow_fsb + cmap.br_blockcount)
1325 			end_fsb = min(end_fsb, data_fsb);
1326 		xfs_trim_extent(&cmap, offset_fsb, end_fsb);
1327 		seq = xfs_iomap_inode_sequence(ip, IOMAP_F_SHARED);
1328 		error = xfs_bmbt_to_iomap(ip, iomap, &cmap, flags,
1329 				IOMAP_F_SHARED, seq);
1330 		/*
1331 		 * This is a COW extent, so we must probe the page cache
1332 		 * because there could be dirty page cache being backed
1333 		 * by this extent.
1334 		 */
1335 		iomap->type = IOMAP_UNWRITTEN;
1336 		goto out_unlock;
1337 	}
1338 
1339 	/*
1340 	 * Else report a hole, capped to the next found data or COW extent.
1341 	 */
1342 	if (cow_fsb != NULLFILEOFF && cow_fsb < data_fsb)
1343 		imap.br_blockcount = cow_fsb - offset_fsb;
1344 	else
1345 		imap.br_blockcount = data_fsb - offset_fsb;
1346 	imap.br_startoff = offset_fsb;
1347 	imap.br_startblock = HOLESTARTBLOCK;
1348 	imap.br_state = XFS_EXT_NORM;
1349 done:
1350 	seq = xfs_iomap_inode_sequence(ip, 0);
1351 	xfs_trim_extent(&imap, offset_fsb, end_fsb);
1352 	error = xfs_bmbt_to_iomap(ip, iomap, &imap, flags, 0, seq);
1353 out_unlock:
1354 	xfs_iunlock(ip, lockmode);
1355 	return error;
1356 }
1357 
1358 const struct iomap_ops xfs_seek_iomap_ops = {
1359 	.iomap_begin		= xfs_seek_iomap_begin,
1360 };
1361 
1362 static int
xfs_xattr_iomap_begin(struct inode * inode,loff_t offset,loff_t length,unsigned flags,struct iomap * iomap,struct iomap * srcmap)1363 xfs_xattr_iomap_begin(
1364 	struct inode		*inode,
1365 	loff_t			offset,
1366 	loff_t			length,
1367 	unsigned		flags,
1368 	struct iomap		*iomap,
1369 	struct iomap		*srcmap)
1370 {
1371 	struct xfs_inode	*ip = XFS_I(inode);
1372 	struct xfs_mount	*mp = ip->i_mount;
1373 	xfs_fileoff_t		offset_fsb = XFS_B_TO_FSBT(mp, offset);
1374 	xfs_fileoff_t		end_fsb = XFS_B_TO_FSB(mp, offset + length);
1375 	struct xfs_bmbt_irec	imap;
1376 	int			nimaps = 1, error = 0;
1377 	unsigned		lockmode;
1378 	int			seq;
1379 
1380 	if (xfs_is_shutdown(mp))
1381 		return -EIO;
1382 
1383 	lockmode = xfs_ilock_attr_map_shared(ip);
1384 
1385 	/* if there are no attribute fork or extents, return ENOENT */
1386 	if (!xfs_inode_has_attr_fork(ip) || !ip->i_af.if_nextents) {
1387 		error = -ENOENT;
1388 		goto out_unlock;
1389 	}
1390 
1391 	ASSERT(ip->i_af.if_format != XFS_DINODE_FMT_LOCAL);
1392 	error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap,
1393 			       &nimaps, XFS_BMAPI_ATTRFORK);
1394 out_unlock:
1395 
1396 	seq = xfs_iomap_inode_sequence(ip, IOMAP_F_XATTR);
1397 	xfs_iunlock(ip, lockmode);
1398 
1399 	if (error)
1400 		return error;
1401 	ASSERT(nimaps);
1402 	return xfs_bmbt_to_iomap(ip, iomap, &imap, flags, IOMAP_F_XATTR, seq);
1403 }
1404 
1405 const struct iomap_ops xfs_xattr_iomap_ops = {
1406 	.iomap_begin		= xfs_xattr_iomap_begin,
1407 };
1408 
1409 int
xfs_zero_range(struct xfs_inode * ip,loff_t pos,loff_t len,bool * did_zero)1410 xfs_zero_range(
1411 	struct xfs_inode	*ip,
1412 	loff_t			pos,
1413 	loff_t			len,
1414 	bool			*did_zero)
1415 {
1416 	struct inode		*inode = VFS_I(ip);
1417 
1418 	if (IS_DAX(inode))
1419 		return dax_zero_range(inode, pos, len, did_zero,
1420 				      &xfs_dax_write_iomap_ops);
1421 	return iomap_zero_range(inode, pos, len, did_zero,
1422 				&xfs_buffered_write_iomap_ops);
1423 }
1424 
1425 int
xfs_truncate_page(struct xfs_inode * ip,loff_t pos,bool * did_zero)1426 xfs_truncate_page(
1427 	struct xfs_inode	*ip,
1428 	loff_t			pos,
1429 	bool			*did_zero)
1430 {
1431 	struct inode		*inode = VFS_I(ip);
1432 
1433 	if (IS_DAX(inode))
1434 		return dax_truncate_page(inode, pos, did_zero,
1435 					&xfs_dax_write_iomap_ops);
1436 	return iomap_truncate_page(inode, pos, did_zero,
1437 				   &xfs_buffered_write_iomap_ops);
1438 }
1439