xfs_file.c revision 75c8c50f
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
4 * All Rights Reserved.
5 */
6#include "xfs.h"
7#include "xfs_fs.h"
8#include "xfs_shared.h"
9#include "xfs_format.h"
10#include "xfs_log_format.h"
11#include "xfs_trans_resv.h"
12#include "xfs_mount.h"
13#include "xfs_inode.h"
14#include "xfs_trans.h"
15#include "xfs_inode_item.h"
16#include "xfs_bmap.h"
17#include "xfs_bmap_util.h"
18#include "xfs_dir2.h"
19#include "xfs_dir2_priv.h"
20#include "xfs_ioctl.h"
21#include "xfs_trace.h"
22#include "xfs_log.h"
23#include "xfs_icache.h"
24#include "xfs_pnfs.h"
25#include "xfs_iomap.h"
26#include "xfs_reflink.h"
27
28#include <linux/falloc.h>
29#include <linux/backing-dev.h>
30#include <linux/mman.h>
31#include <linux/fadvise.h>
32#include <linux/mount.h>
33
34static const struct vm_operations_struct xfs_file_vm_ops;
35
36/*
37 * Decide if the given file range is aligned to the size of the fundamental
38 * allocation unit for the file.
39 */
40static bool
41xfs_is_falloc_aligned(
42	struct xfs_inode	*ip,
43	loff_t			pos,
44	long long int		len)
45{
46	struct xfs_mount	*mp = ip->i_mount;
47	uint64_t		mask;
48
49	if (XFS_IS_REALTIME_INODE(ip)) {
50		if (!is_power_of_2(mp->m_sb.sb_rextsize)) {
51			u64	rextbytes;
52			u32	mod;
53
54			rextbytes = XFS_FSB_TO_B(mp, mp->m_sb.sb_rextsize);
55			div_u64_rem(pos, rextbytes, &mod);
56			if (mod)
57				return false;
58			div_u64_rem(len, rextbytes, &mod);
59			return mod == 0;
60		}
61		mask = XFS_FSB_TO_B(mp, mp->m_sb.sb_rextsize) - 1;
62	} else {
63		mask = mp->m_sb.sb_blocksize - 1;
64	}
65
66	return !((pos | len) & mask);
67}
68
69int
70xfs_update_prealloc_flags(
71	struct xfs_inode	*ip,
72	enum xfs_prealloc_flags	flags)
73{
74	struct xfs_trans	*tp;
75	int			error;
76
77	error = xfs_trans_alloc(ip->i_mount, &M_RES(ip->i_mount)->tr_writeid,
78			0, 0, 0, &tp);
79	if (error)
80		return error;
81
82	xfs_ilock(ip, XFS_ILOCK_EXCL);
83	xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
84
85	if (!(flags & XFS_PREALLOC_INVISIBLE)) {
86		VFS_I(ip)->i_mode &= ~S_ISUID;
87		if (VFS_I(ip)->i_mode & S_IXGRP)
88			VFS_I(ip)->i_mode &= ~S_ISGID;
89		xfs_trans_ichgtime(tp, ip, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
90	}
91
92	if (flags & XFS_PREALLOC_SET)
93		ip->i_diflags |= XFS_DIFLAG_PREALLOC;
94	if (flags & XFS_PREALLOC_CLEAR)
95		ip->i_diflags &= ~XFS_DIFLAG_PREALLOC;
96
97	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
98	if (flags & XFS_PREALLOC_SYNC)
99		xfs_trans_set_sync(tp);
100	return xfs_trans_commit(tp);
101}
102
103/*
104 * Fsync operations on directories are much simpler than on regular files,
105 * as there is no file data to flush, and thus also no need for explicit
106 * cache flush operations, and there are no non-transaction metadata updates
107 * on directories either.
108 */
109STATIC int
110xfs_dir_fsync(
111	struct file		*file,
112	loff_t			start,
113	loff_t			end,
114	int			datasync)
115{
116	struct xfs_inode	*ip = XFS_I(file->f_mapping->host);
117
118	trace_xfs_dir_fsync(ip);
119	return xfs_log_force_inode(ip);
120}
121
122static xfs_csn_t
123xfs_fsync_seq(
124	struct xfs_inode	*ip,
125	bool			datasync)
126{
127	if (!xfs_ipincount(ip))
128		return 0;
129	if (datasync && !(ip->i_itemp->ili_fsync_fields & ~XFS_ILOG_TIMESTAMP))
130		return 0;
131	return ip->i_itemp->ili_commit_seq;
132}
133
134/*
135 * All metadata updates are logged, which means that we just have to flush the
136 * log up to the latest LSN that touched the inode.
137 *
138 * If we have concurrent fsync/fdatasync() calls, we need them to all block on
139 * the log force before we clear the ili_fsync_fields field. This ensures that
140 * we don't get a racing sync operation that does not wait for the metadata to
141 * hit the journal before returning.  If we race with clearing ili_fsync_fields,
142 * then all that will happen is the log force will do nothing as the lsn will
143 * already be on disk.  We can't race with setting ili_fsync_fields because that
144 * is done under XFS_ILOCK_EXCL, and that can't happen because we hold the lock
145 * shared until after the ili_fsync_fields is cleared.
146 */
147static  int
148xfs_fsync_flush_log(
149	struct xfs_inode	*ip,
150	bool			datasync,
151	int			*log_flushed)
152{
153	int			error = 0;
154	xfs_csn_t		seq;
155
156	xfs_ilock(ip, XFS_ILOCK_SHARED);
157	seq = xfs_fsync_seq(ip, datasync);
158	if (seq) {
159		error = xfs_log_force_seq(ip->i_mount, seq, XFS_LOG_SYNC,
160					  log_flushed);
161
162		spin_lock(&ip->i_itemp->ili_lock);
163		ip->i_itemp->ili_fsync_fields = 0;
164		spin_unlock(&ip->i_itemp->ili_lock);
165	}
166	xfs_iunlock(ip, XFS_ILOCK_SHARED);
167	return error;
168}
169
170STATIC int
171xfs_file_fsync(
172	struct file		*file,
173	loff_t			start,
174	loff_t			end,
175	int			datasync)
176{
177	struct xfs_inode	*ip = XFS_I(file->f_mapping->host);
178	struct xfs_mount	*mp = ip->i_mount;
179	int			error = 0;
180	int			log_flushed = 0;
181
182	trace_xfs_file_fsync(ip);
183
184	error = file_write_and_wait_range(file, start, end);
185	if (error)
186		return error;
187
188	if (xfs_is_shutdown(mp))
189		return -EIO;
190
191	xfs_iflags_clear(ip, XFS_ITRUNCATED);
192
193	/*
194	 * If we have an RT and/or log subvolume we need to make sure to flush
195	 * the write cache the device used for file data first.  This is to
196	 * ensure newly written file data make it to disk before logging the new
197	 * inode size in case of an extending write.
198	 */
199	if (XFS_IS_REALTIME_INODE(ip))
200		blkdev_issue_flush(mp->m_rtdev_targp->bt_bdev);
201	else if (mp->m_logdev_targp != mp->m_ddev_targp)
202		blkdev_issue_flush(mp->m_ddev_targp->bt_bdev);
203
204	/*
205	 * Any inode that has dirty modifications in the log is pinned.  The
206	 * racy check here for a pinned inode while not catch modifications
207	 * that happen concurrently to the fsync call, but fsync semantics
208	 * only require to sync previously completed I/O.
209	 */
210	if (xfs_ipincount(ip))
211		error = xfs_fsync_flush_log(ip, datasync, &log_flushed);
212
213	/*
214	 * If we only have a single device, and the log force about was
215	 * a no-op we might have to flush the data device cache here.
216	 * This can only happen for fdatasync/O_DSYNC if we were overwriting
217	 * an already allocated file and thus do not have any metadata to
218	 * commit.
219	 */
220	if (!log_flushed && !XFS_IS_REALTIME_INODE(ip) &&
221	    mp->m_logdev_targp == mp->m_ddev_targp)
222		blkdev_issue_flush(mp->m_ddev_targp->bt_bdev);
223
224	return error;
225}
226
227static int
228xfs_ilock_iocb(
229	struct kiocb		*iocb,
230	unsigned int		lock_mode)
231{
232	struct xfs_inode	*ip = XFS_I(file_inode(iocb->ki_filp));
233
234	if (iocb->ki_flags & IOCB_NOWAIT) {
235		if (!xfs_ilock_nowait(ip, lock_mode))
236			return -EAGAIN;
237	} else {
238		xfs_ilock(ip, lock_mode);
239	}
240
241	return 0;
242}
243
244STATIC ssize_t
245xfs_file_dio_read(
246	struct kiocb		*iocb,
247	struct iov_iter		*to)
248{
249	struct xfs_inode	*ip = XFS_I(file_inode(iocb->ki_filp));
250	ssize_t			ret;
251
252	trace_xfs_file_direct_read(iocb, to);
253
254	if (!iov_iter_count(to))
255		return 0; /* skip atime */
256
257	file_accessed(iocb->ki_filp);
258
259	ret = xfs_ilock_iocb(iocb, XFS_IOLOCK_SHARED);
260	if (ret)
261		return ret;
262	ret = iomap_dio_rw(iocb, to, &xfs_read_iomap_ops, NULL, 0);
263	xfs_iunlock(ip, XFS_IOLOCK_SHARED);
264
265	return ret;
266}
267
268static noinline ssize_t
269xfs_file_dax_read(
270	struct kiocb		*iocb,
271	struct iov_iter		*to)
272{
273	struct xfs_inode	*ip = XFS_I(iocb->ki_filp->f_mapping->host);
274	ssize_t			ret = 0;
275
276	trace_xfs_file_dax_read(iocb, to);
277
278	if (!iov_iter_count(to))
279		return 0; /* skip atime */
280
281	ret = xfs_ilock_iocb(iocb, XFS_IOLOCK_SHARED);
282	if (ret)
283		return ret;
284	ret = dax_iomap_rw(iocb, to, &xfs_read_iomap_ops);
285	xfs_iunlock(ip, XFS_IOLOCK_SHARED);
286
287	file_accessed(iocb->ki_filp);
288	return ret;
289}
290
291STATIC ssize_t
292xfs_file_buffered_read(
293	struct kiocb		*iocb,
294	struct iov_iter		*to)
295{
296	struct xfs_inode	*ip = XFS_I(file_inode(iocb->ki_filp));
297	ssize_t			ret;
298
299	trace_xfs_file_buffered_read(iocb, to);
300
301	ret = xfs_ilock_iocb(iocb, XFS_IOLOCK_SHARED);
302	if (ret)
303		return ret;
304	ret = generic_file_read_iter(iocb, to);
305	xfs_iunlock(ip, XFS_IOLOCK_SHARED);
306
307	return ret;
308}
309
310STATIC ssize_t
311xfs_file_read_iter(
312	struct kiocb		*iocb,
313	struct iov_iter		*to)
314{
315	struct inode		*inode = file_inode(iocb->ki_filp);
316	struct xfs_mount	*mp = XFS_I(inode)->i_mount;
317	ssize_t			ret = 0;
318
319	XFS_STATS_INC(mp, xs_read_calls);
320
321	if (xfs_is_shutdown(mp))
322		return -EIO;
323
324	if (IS_DAX(inode))
325		ret = xfs_file_dax_read(iocb, to);
326	else if (iocb->ki_flags & IOCB_DIRECT)
327		ret = xfs_file_dio_read(iocb, to);
328	else
329		ret = xfs_file_buffered_read(iocb, to);
330
331	if (ret > 0)
332		XFS_STATS_ADD(mp, xs_read_bytes, ret);
333	return ret;
334}
335
336/*
337 * Common pre-write limit and setup checks.
338 *
339 * Called with the iolocked held either shared and exclusive according to
340 * @iolock, and returns with it held.  Might upgrade the iolock to exclusive
341 * if called for a direct write beyond i_size.
342 */
343STATIC ssize_t
344xfs_file_write_checks(
345	struct kiocb		*iocb,
346	struct iov_iter		*from,
347	int			*iolock)
348{
349	struct file		*file = iocb->ki_filp;
350	struct inode		*inode = file->f_mapping->host;
351	struct xfs_inode	*ip = XFS_I(inode);
352	ssize_t			error = 0;
353	size_t			count = iov_iter_count(from);
354	bool			drained_dio = false;
355	loff_t			isize;
356
357restart:
358	error = generic_write_checks(iocb, from);
359	if (error <= 0)
360		return error;
361
362	if (iocb->ki_flags & IOCB_NOWAIT) {
363		error = break_layout(inode, false);
364		if (error == -EWOULDBLOCK)
365			error = -EAGAIN;
366	} else {
367		error = xfs_break_layouts(inode, iolock, BREAK_WRITE);
368	}
369
370	if (error)
371		return error;
372
373	/*
374	 * For changing security info in file_remove_privs() we need i_rwsem
375	 * exclusively.
376	 */
377	if (*iolock == XFS_IOLOCK_SHARED && !IS_NOSEC(inode)) {
378		xfs_iunlock(ip, *iolock);
379		*iolock = XFS_IOLOCK_EXCL;
380		error = xfs_ilock_iocb(iocb, *iolock);
381		if (error) {
382			*iolock = 0;
383			return error;
384		}
385		goto restart;
386	}
387
388	/*
389	 * If the offset is beyond the size of the file, we need to zero any
390	 * blocks that fall between the existing EOF and the start of this
391	 * write.  If zeroing is needed and we are currently holding the iolock
392	 * shared, we need to update it to exclusive which implies having to
393	 * redo all checks before.
394	 *
395	 * We need to serialise against EOF updates that occur in IO completions
396	 * here. We want to make sure that nobody is changing the size while we
397	 * do this check until we have placed an IO barrier (i.e.  hold the
398	 * XFS_IOLOCK_EXCL) that prevents new IO from being dispatched.  The
399	 * spinlock effectively forms a memory barrier once we have the
400	 * XFS_IOLOCK_EXCL so we are guaranteed to see the latest EOF value and
401	 * hence be able to correctly determine if we need to run zeroing.
402	 *
403	 * We can do an unlocked check here safely as IO completion can only
404	 * extend EOF. Truncate is locked out at this point, so the EOF can
405	 * not move backwards, only forwards. Hence we only need to take the
406	 * slow path and spin locks when we are at or beyond the current EOF.
407	 */
408	if (iocb->ki_pos <= i_size_read(inode))
409		goto out;
410
411	spin_lock(&ip->i_flags_lock);
412	isize = i_size_read(inode);
413	if (iocb->ki_pos > isize) {
414		spin_unlock(&ip->i_flags_lock);
415
416		if (iocb->ki_flags & IOCB_NOWAIT)
417			return -EAGAIN;
418
419		if (!drained_dio) {
420			if (*iolock == XFS_IOLOCK_SHARED) {
421				xfs_iunlock(ip, *iolock);
422				*iolock = XFS_IOLOCK_EXCL;
423				xfs_ilock(ip, *iolock);
424				iov_iter_reexpand(from, count);
425			}
426			/*
427			 * We now have an IO submission barrier in place, but
428			 * AIO can do EOF updates during IO completion and hence
429			 * we now need to wait for all of them to drain. Non-AIO
430			 * DIO will have drained before we are given the
431			 * XFS_IOLOCK_EXCL, and so for most cases this wait is a
432			 * no-op.
433			 */
434			inode_dio_wait(inode);
435			drained_dio = true;
436			goto restart;
437		}
438
439		trace_xfs_zero_eof(ip, isize, iocb->ki_pos - isize);
440		error = iomap_zero_range(inode, isize, iocb->ki_pos - isize,
441				NULL, &xfs_buffered_write_iomap_ops);
442		if (error)
443			return error;
444	} else
445		spin_unlock(&ip->i_flags_lock);
446
447out:
448	return file_modified(file);
449}
450
451static int
452xfs_dio_write_end_io(
453	struct kiocb		*iocb,
454	ssize_t			size,
455	int			error,
456	unsigned		flags)
457{
458	struct inode		*inode = file_inode(iocb->ki_filp);
459	struct xfs_inode	*ip = XFS_I(inode);
460	loff_t			offset = iocb->ki_pos;
461	unsigned int		nofs_flag;
462
463	trace_xfs_end_io_direct_write(ip, offset, size);
464
465	if (xfs_is_shutdown(ip->i_mount))
466		return -EIO;
467
468	if (error)
469		return error;
470	if (!size)
471		return 0;
472
473	/*
474	 * Capture amount written on completion as we can't reliably account
475	 * for it on submission.
476	 */
477	XFS_STATS_ADD(ip->i_mount, xs_write_bytes, size);
478
479	/*
480	 * We can allocate memory here while doing writeback on behalf of
481	 * memory reclaim.  To avoid memory allocation deadlocks set the
482	 * task-wide nofs context for the following operations.
483	 */
484	nofs_flag = memalloc_nofs_save();
485
486	if (flags & IOMAP_DIO_COW) {
487		error = xfs_reflink_end_cow(ip, offset, size);
488		if (error)
489			goto out;
490	}
491
492	/*
493	 * Unwritten conversion updates the in-core isize after extent
494	 * conversion but before updating the on-disk size. Updating isize any
495	 * earlier allows a racing dio read to find unwritten extents before
496	 * they are converted.
497	 */
498	if (flags & IOMAP_DIO_UNWRITTEN) {
499		error = xfs_iomap_write_unwritten(ip, offset, size, true);
500		goto out;
501	}
502
503	/*
504	 * We need to update the in-core inode size here so that we don't end up
505	 * with the on-disk inode size being outside the in-core inode size. We
506	 * have no other method of updating EOF for AIO, so always do it here
507	 * if necessary.
508	 *
509	 * We need to lock the test/set EOF update as we can be racing with
510	 * other IO completions here to update the EOF. Failing to serialise
511	 * here can result in EOF moving backwards and Bad Things Happen when
512	 * that occurs.
513	 *
514	 * As IO completion only ever extends EOF, we can do an unlocked check
515	 * here to avoid taking the spinlock. If we land within the current EOF,
516	 * then we do not need to do an extending update at all, and we don't
517	 * need to take the lock to check this. If we race with an update moving
518	 * EOF, then we'll either still be beyond EOF and need to take the lock,
519	 * or we'll be within EOF and we don't need to take it at all.
520	 */
521	if (offset + size <= i_size_read(inode))
522		goto out;
523
524	spin_lock(&ip->i_flags_lock);
525	if (offset + size > i_size_read(inode)) {
526		i_size_write(inode, offset + size);
527		spin_unlock(&ip->i_flags_lock);
528		error = xfs_setfilesize(ip, offset, size);
529	} else {
530		spin_unlock(&ip->i_flags_lock);
531	}
532
533out:
534	memalloc_nofs_restore(nofs_flag);
535	return error;
536}
537
538static const struct iomap_dio_ops xfs_dio_write_ops = {
539	.end_io		= xfs_dio_write_end_io,
540};
541
542/*
543 * Handle block aligned direct I/O writes
544 */
545static noinline ssize_t
546xfs_file_dio_write_aligned(
547	struct xfs_inode	*ip,
548	struct kiocb		*iocb,
549	struct iov_iter		*from)
550{
551	int			iolock = XFS_IOLOCK_SHARED;
552	ssize_t			ret;
553
554	ret = xfs_ilock_iocb(iocb, iolock);
555	if (ret)
556		return ret;
557	ret = xfs_file_write_checks(iocb, from, &iolock);
558	if (ret)
559		goto out_unlock;
560
561	/*
562	 * We don't need to hold the IOLOCK exclusively across the IO, so demote
563	 * the iolock back to shared if we had to take the exclusive lock in
564	 * xfs_file_write_checks() for other reasons.
565	 */
566	if (iolock == XFS_IOLOCK_EXCL) {
567		xfs_ilock_demote(ip, XFS_IOLOCK_EXCL);
568		iolock = XFS_IOLOCK_SHARED;
569	}
570	trace_xfs_file_direct_write(iocb, from);
571	ret = iomap_dio_rw(iocb, from, &xfs_direct_write_iomap_ops,
572			   &xfs_dio_write_ops, 0);
573out_unlock:
574	if (iolock)
575		xfs_iunlock(ip, iolock);
576	return ret;
577}
578
579/*
580 * Handle block unaligned direct I/O writes
581 *
582 * In most cases direct I/O writes will be done holding IOLOCK_SHARED, allowing
583 * them to be done in parallel with reads and other direct I/O writes.  However,
584 * if the I/O is not aligned to filesystem blocks, the direct I/O layer may need
585 * to do sub-block zeroing and that requires serialisation against other direct
586 * I/O to the same block.  In this case we need to serialise the submission of
587 * the unaligned I/O so that we don't get racing block zeroing in the dio layer.
588 * In the case where sub-block zeroing is not required, we can do concurrent
589 * sub-block dios to the same block successfully.
590 *
591 * Optimistically submit the I/O using the shared lock first, but use the
592 * IOMAP_DIO_OVERWRITE_ONLY flag to tell the lower layers to return -EAGAIN
593 * if block allocation or partial block zeroing would be required.  In that case
594 * we try again with the exclusive lock.
595 */
596static noinline ssize_t
597xfs_file_dio_write_unaligned(
598	struct xfs_inode	*ip,
599	struct kiocb		*iocb,
600	struct iov_iter		*from)
601{
602	size_t			isize = i_size_read(VFS_I(ip));
603	size_t			count = iov_iter_count(from);
604	int			iolock = XFS_IOLOCK_SHARED;
605	unsigned int		flags = IOMAP_DIO_OVERWRITE_ONLY;
606	ssize_t			ret;
607
608	/*
609	 * Extending writes need exclusivity because of the sub-block zeroing
610	 * that the DIO code always does for partial tail blocks beyond EOF, so
611	 * don't even bother trying the fast path in this case.
612	 */
613	if (iocb->ki_pos > isize || iocb->ki_pos + count >= isize) {
614retry_exclusive:
615		if (iocb->ki_flags & IOCB_NOWAIT)
616			return -EAGAIN;
617		iolock = XFS_IOLOCK_EXCL;
618		flags = IOMAP_DIO_FORCE_WAIT;
619	}
620
621	ret = xfs_ilock_iocb(iocb, iolock);
622	if (ret)
623		return ret;
624
625	/*
626	 * We can't properly handle unaligned direct I/O to reflink files yet,
627	 * as we can't unshare a partial block.
628	 */
629	if (xfs_is_cow_inode(ip)) {
630		trace_xfs_reflink_bounce_dio_write(iocb, from);
631		ret = -ENOTBLK;
632		goto out_unlock;
633	}
634
635	ret = xfs_file_write_checks(iocb, from, &iolock);
636	if (ret)
637		goto out_unlock;
638
639	/*
640	 * If we are doing exclusive unaligned I/O, this must be the only I/O
641	 * in-flight.  Otherwise we risk data corruption due to unwritten extent
642	 * conversions from the AIO end_io handler.  Wait for all other I/O to
643	 * drain first.
644	 */
645	if (flags & IOMAP_DIO_FORCE_WAIT)
646		inode_dio_wait(VFS_I(ip));
647
648	trace_xfs_file_direct_write(iocb, from);
649	ret = iomap_dio_rw(iocb, from, &xfs_direct_write_iomap_ops,
650			   &xfs_dio_write_ops, flags);
651
652	/*
653	 * Retry unaligned I/O with exclusive blocking semantics if the DIO
654	 * layer rejected it for mapping or locking reasons. If we are doing
655	 * nonblocking user I/O, propagate the error.
656	 */
657	if (ret == -EAGAIN && !(iocb->ki_flags & IOCB_NOWAIT)) {
658		ASSERT(flags & IOMAP_DIO_OVERWRITE_ONLY);
659		xfs_iunlock(ip, iolock);
660		goto retry_exclusive;
661	}
662
663out_unlock:
664	if (iolock)
665		xfs_iunlock(ip, iolock);
666	return ret;
667}
668
669static ssize_t
670xfs_file_dio_write(
671	struct kiocb		*iocb,
672	struct iov_iter		*from)
673{
674	struct xfs_inode	*ip = XFS_I(file_inode(iocb->ki_filp));
675	struct xfs_buftarg      *target = xfs_inode_buftarg(ip);
676	size_t			count = iov_iter_count(from);
677
678	/* direct I/O must be aligned to device logical sector size */
679	if ((iocb->ki_pos | count) & target->bt_logical_sectormask)
680		return -EINVAL;
681	if ((iocb->ki_pos | count) & ip->i_mount->m_blockmask)
682		return xfs_file_dio_write_unaligned(ip, iocb, from);
683	return xfs_file_dio_write_aligned(ip, iocb, from);
684}
685
686static noinline ssize_t
687xfs_file_dax_write(
688	struct kiocb		*iocb,
689	struct iov_iter		*from)
690{
691	struct inode		*inode = iocb->ki_filp->f_mapping->host;
692	struct xfs_inode	*ip = XFS_I(inode);
693	int			iolock = XFS_IOLOCK_EXCL;
694	ssize_t			ret, error = 0;
695	loff_t			pos;
696
697	ret = xfs_ilock_iocb(iocb, iolock);
698	if (ret)
699		return ret;
700	ret = xfs_file_write_checks(iocb, from, &iolock);
701	if (ret)
702		goto out;
703
704	pos = iocb->ki_pos;
705
706	trace_xfs_file_dax_write(iocb, from);
707	ret = dax_iomap_rw(iocb, from, &xfs_direct_write_iomap_ops);
708	if (ret > 0 && iocb->ki_pos > i_size_read(inode)) {
709		i_size_write(inode, iocb->ki_pos);
710		error = xfs_setfilesize(ip, pos, ret);
711	}
712out:
713	if (iolock)
714		xfs_iunlock(ip, iolock);
715	if (error)
716		return error;
717
718	if (ret > 0) {
719		XFS_STATS_ADD(ip->i_mount, xs_write_bytes, ret);
720
721		/* Handle various SYNC-type writes */
722		ret = generic_write_sync(iocb, ret);
723	}
724	return ret;
725}
726
727STATIC ssize_t
728xfs_file_buffered_write(
729	struct kiocb		*iocb,
730	struct iov_iter		*from)
731{
732	struct file		*file = iocb->ki_filp;
733	struct address_space	*mapping = file->f_mapping;
734	struct inode		*inode = mapping->host;
735	struct xfs_inode	*ip = XFS_I(inode);
736	ssize_t			ret;
737	bool			cleared_space = false;
738	int			iolock;
739
740	if (iocb->ki_flags & IOCB_NOWAIT)
741		return -EOPNOTSUPP;
742
743write_retry:
744	iolock = XFS_IOLOCK_EXCL;
745	xfs_ilock(ip, iolock);
746
747	ret = xfs_file_write_checks(iocb, from, &iolock);
748	if (ret)
749		goto out;
750
751	/* We can write back this queue in page reclaim */
752	current->backing_dev_info = inode_to_bdi(inode);
753
754	trace_xfs_file_buffered_write(iocb, from);
755	ret = iomap_file_buffered_write(iocb, from,
756			&xfs_buffered_write_iomap_ops);
757	if (likely(ret >= 0))
758		iocb->ki_pos += ret;
759
760	/*
761	 * If we hit a space limit, try to free up some lingering preallocated
762	 * space before returning an error. In the case of ENOSPC, first try to
763	 * write back all dirty inodes to free up some of the excess reserved
764	 * metadata space. This reduces the chances that the eofblocks scan
765	 * waits on dirty mappings. Since xfs_flush_inodes() is serialized, this
766	 * also behaves as a filter to prevent too many eofblocks scans from
767	 * running at the same time.  Use a synchronous scan to increase the
768	 * effectiveness of the scan.
769	 */
770	if (ret == -EDQUOT && !cleared_space) {
771		xfs_iunlock(ip, iolock);
772		xfs_blockgc_free_quota(ip, XFS_ICWALK_FLAG_SYNC);
773		cleared_space = true;
774		goto write_retry;
775	} else if (ret == -ENOSPC && !cleared_space) {
776		struct xfs_icwalk	icw = {0};
777
778		cleared_space = true;
779		xfs_flush_inodes(ip->i_mount);
780
781		xfs_iunlock(ip, iolock);
782		icw.icw_flags = XFS_ICWALK_FLAG_SYNC;
783		xfs_blockgc_free_space(ip->i_mount, &icw);
784		goto write_retry;
785	}
786
787	current->backing_dev_info = NULL;
788out:
789	if (iolock)
790		xfs_iunlock(ip, iolock);
791
792	if (ret > 0) {
793		XFS_STATS_ADD(ip->i_mount, xs_write_bytes, ret);
794		/* Handle various SYNC-type writes */
795		ret = generic_write_sync(iocb, ret);
796	}
797	return ret;
798}
799
800STATIC ssize_t
801xfs_file_write_iter(
802	struct kiocb		*iocb,
803	struct iov_iter		*from)
804{
805	struct file		*file = iocb->ki_filp;
806	struct address_space	*mapping = file->f_mapping;
807	struct inode		*inode = mapping->host;
808	struct xfs_inode	*ip = XFS_I(inode);
809	ssize_t			ret;
810	size_t			ocount = iov_iter_count(from);
811
812	XFS_STATS_INC(ip->i_mount, xs_write_calls);
813
814	if (ocount == 0)
815		return 0;
816
817	if (xfs_is_shutdown(ip->i_mount))
818		return -EIO;
819
820	if (IS_DAX(inode))
821		return xfs_file_dax_write(iocb, from);
822
823	if (iocb->ki_flags & IOCB_DIRECT) {
824		/*
825		 * Allow a directio write to fall back to a buffered
826		 * write *only* in the case that we're doing a reflink
827		 * CoW.  In all other directio scenarios we do not
828		 * allow an operation to fall back to buffered mode.
829		 */
830		ret = xfs_file_dio_write(iocb, from);
831		if (ret != -ENOTBLK)
832			return ret;
833	}
834
835	return xfs_file_buffered_write(iocb, from);
836}
837
838static void
839xfs_wait_dax_page(
840	struct inode		*inode)
841{
842	struct xfs_inode        *ip = XFS_I(inode);
843
844	xfs_iunlock(ip, XFS_MMAPLOCK_EXCL);
845	schedule();
846	xfs_ilock(ip, XFS_MMAPLOCK_EXCL);
847}
848
849static int
850xfs_break_dax_layouts(
851	struct inode		*inode,
852	bool			*retry)
853{
854	struct page		*page;
855
856	ASSERT(xfs_isilocked(XFS_I(inode), XFS_MMAPLOCK_EXCL));
857
858	page = dax_layout_busy_page(inode->i_mapping);
859	if (!page)
860		return 0;
861
862	*retry = true;
863	return ___wait_var_event(&page->_refcount,
864			atomic_read(&page->_refcount) == 1, TASK_INTERRUPTIBLE,
865			0, 0, xfs_wait_dax_page(inode));
866}
867
868int
869xfs_break_layouts(
870	struct inode		*inode,
871	uint			*iolock,
872	enum layout_break_reason reason)
873{
874	bool			retry;
875	int			error;
876
877	ASSERT(xfs_isilocked(XFS_I(inode), XFS_IOLOCK_SHARED|XFS_IOLOCK_EXCL));
878
879	do {
880		retry = false;
881		switch (reason) {
882		case BREAK_UNMAP:
883			error = xfs_break_dax_layouts(inode, &retry);
884			if (error || retry)
885				break;
886			fallthrough;
887		case BREAK_WRITE:
888			error = xfs_break_leased_layouts(inode, iolock, &retry);
889			break;
890		default:
891			WARN_ON_ONCE(1);
892			error = -EINVAL;
893		}
894	} while (error == 0 && retry);
895
896	return error;
897}
898
899#define	XFS_FALLOC_FL_SUPPORTED						\
900		(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |		\
901		 FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE |	\
902		 FALLOC_FL_INSERT_RANGE | FALLOC_FL_UNSHARE_RANGE)
903
904STATIC long
905xfs_file_fallocate(
906	struct file		*file,
907	int			mode,
908	loff_t			offset,
909	loff_t			len)
910{
911	struct inode		*inode = file_inode(file);
912	struct xfs_inode	*ip = XFS_I(inode);
913	long			error;
914	enum xfs_prealloc_flags	flags = 0;
915	uint			iolock = XFS_IOLOCK_EXCL | XFS_MMAPLOCK_EXCL;
916	loff_t			new_size = 0;
917	bool			do_file_insert = false;
918
919	if (!S_ISREG(inode->i_mode))
920		return -EINVAL;
921	if (mode & ~XFS_FALLOC_FL_SUPPORTED)
922		return -EOPNOTSUPP;
923
924	xfs_ilock(ip, iolock);
925	error = xfs_break_layouts(inode, &iolock, BREAK_UNMAP);
926	if (error)
927		goto out_unlock;
928
929	/*
930	 * Must wait for all AIO to complete before we continue as AIO can
931	 * change the file size on completion without holding any locks we
932	 * currently hold. We must do this first because AIO can update both
933	 * the on disk and in memory inode sizes, and the operations that follow
934	 * require the in-memory size to be fully up-to-date.
935	 */
936	inode_dio_wait(inode);
937
938	/*
939	 * Now AIO and DIO has drained we flush and (if necessary) invalidate
940	 * the cached range over the first operation we are about to run.
941	 *
942	 * We care about zero and collapse here because they both run a hole
943	 * punch over the range first. Because that can zero data, and the range
944	 * of invalidation for the shift operations is much larger, we still do
945	 * the required flush for collapse in xfs_prepare_shift().
946	 *
947	 * Insert has the same range requirements as collapse, and we extend the
948	 * file first which can zero data. Hence insert has the same
949	 * flush/invalidate requirements as collapse and so they are both
950	 * handled at the right time by xfs_prepare_shift().
951	 */
952	if (mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE |
953		    FALLOC_FL_COLLAPSE_RANGE)) {
954		error = xfs_flush_unmap_range(ip, offset, len);
955		if (error)
956			goto out_unlock;
957	}
958
959	if (mode & FALLOC_FL_PUNCH_HOLE) {
960		error = xfs_free_file_space(ip, offset, len);
961		if (error)
962			goto out_unlock;
963	} else if (mode & FALLOC_FL_COLLAPSE_RANGE) {
964		if (!xfs_is_falloc_aligned(ip, offset, len)) {
965			error = -EINVAL;
966			goto out_unlock;
967		}
968
969		/*
970		 * There is no need to overlap collapse range with EOF,
971		 * in which case it is effectively a truncate operation
972		 */
973		if (offset + len >= i_size_read(inode)) {
974			error = -EINVAL;
975			goto out_unlock;
976		}
977
978		new_size = i_size_read(inode) - len;
979
980		error = xfs_collapse_file_space(ip, offset, len);
981		if (error)
982			goto out_unlock;
983	} else if (mode & FALLOC_FL_INSERT_RANGE) {
984		loff_t		isize = i_size_read(inode);
985
986		if (!xfs_is_falloc_aligned(ip, offset, len)) {
987			error = -EINVAL;
988			goto out_unlock;
989		}
990
991		/*
992		 * New inode size must not exceed ->s_maxbytes, accounting for
993		 * possible signed overflow.
994		 */
995		if (inode->i_sb->s_maxbytes - isize < len) {
996			error = -EFBIG;
997			goto out_unlock;
998		}
999		new_size = isize + len;
1000
1001		/* Offset should be less than i_size */
1002		if (offset >= isize) {
1003			error = -EINVAL;
1004			goto out_unlock;
1005		}
1006		do_file_insert = true;
1007	} else {
1008		flags |= XFS_PREALLOC_SET;
1009
1010		if (!(mode & FALLOC_FL_KEEP_SIZE) &&
1011		    offset + len > i_size_read(inode)) {
1012			new_size = offset + len;
1013			error = inode_newsize_ok(inode, new_size);
1014			if (error)
1015				goto out_unlock;
1016		}
1017
1018		if (mode & FALLOC_FL_ZERO_RANGE) {
1019			/*
1020			 * Punch a hole and prealloc the range.  We use a hole
1021			 * punch rather than unwritten extent conversion for two
1022			 * reasons:
1023			 *
1024			 *   1.) Hole punch handles partial block zeroing for us.
1025			 *   2.) If prealloc returns ENOSPC, the file range is
1026			 *       still zero-valued by virtue of the hole punch.
1027			 */
1028			unsigned int blksize = i_blocksize(inode);
1029
1030			trace_xfs_zero_file_space(ip);
1031
1032			error = xfs_free_file_space(ip, offset, len);
1033			if (error)
1034				goto out_unlock;
1035
1036			len = round_up(offset + len, blksize) -
1037			      round_down(offset, blksize);
1038			offset = round_down(offset, blksize);
1039		} else if (mode & FALLOC_FL_UNSHARE_RANGE) {
1040			error = xfs_reflink_unshare(ip, offset, len);
1041			if (error)
1042				goto out_unlock;
1043		} else {
1044			/*
1045			 * If always_cow mode we can't use preallocations and
1046			 * thus should not create them.
1047			 */
1048			if (xfs_is_always_cow_inode(ip)) {
1049				error = -EOPNOTSUPP;
1050				goto out_unlock;
1051			}
1052		}
1053
1054		if (!xfs_is_always_cow_inode(ip)) {
1055			error = xfs_alloc_file_space(ip, offset, len,
1056						     XFS_BMAPI_PREALLOC);
1057			if (error)
1058				goto out_unlock;
1059		}
1060	}
1061
1062	if (file->f_flags & O_DSYNC)
1063		flags |= XFS_PREALLOC_SYNC;
1064
1065	error = xfs_update_prealloc_flags(ip, flags);
1066	if (error)
1067		goto out_unlock;
1068
1069	/* Change file size if needed */
1070	if (new_size) {
1071		struct iattr iattr;
1072
1073		iattr.ia_valid = ATTR_SIZE;
1074		iattr.ia_size = new_size;
1075		error = xfs_vn_setattr_size(file_mnt_user_ns(file),
1076					    file_dentry(file), &iattr);
1077		if (error)
1078			goto out_unlock;
1079	}
1080
1081	/*
1082	 * Perform hole insertion now that the file size has been
1083	 * updated so that if we crash during the operation we don't
1084	 * leave shifted extents past EOF and hence losing access to
1085	 * the data that is contained within them.
1086	 */
1087	if (do_file_insert)
1088		error = xfs_insert_file_space(ip, offset, len);
1089
1090out_unlock:
1091	xfs_iunlock(ip, iolock);
1092	return error;
1093}
1094
1095STATIC int
1096xfs_file_fadvise(
1097	struct file	*file,
1098	loff_t		start,
1099	loff_t		end,
1100	int		advice)
1101{
1102	struct xfs_inode *ip = XFS_I(file_inode(file));
1103	int ret;
1104	int lockflags = 0;
1105
1106	/*
1107	 * Operations creating pages in page cache need protection from hole
1108	 * punching and similar ops
1109	 */
1110	if (advice == POSIX_FADV_WILLNEED) {
1111		lockflags = XFS_IOLOCK_SHARED;
1112		xfs_ilock(ip, lockflags);
1113	}
1114	ret = generic_fadvise(file, start, end, advice);
1115	if (lockflags)
1116		xfs_iunlock(ip, lockflags);
1117	return ret;
1118}
1119
1120/* Does this file, inode, or mount want synchronous writes? */
1121static inline bool xfs_file_sync_writes(struct file *filp)
1122{
1123	struct xfs_inode	*ip = XFS_I(file_inode(filp));
1124
1125	if (xfs_has_wsync(ip->i_mount))
1126		return true;
1127	if (filp->f_flags & (__O_SYNC | O_DSYNC))
1128		return true;
1129	if (IS_SYNC(file_inode(filp)))
1130		return true;
1131
1132	return false;
1133}
1134
1135STATIC loff_t
1136xfs_file_remap_range(
1137	struct file		*file_in,
1138	loff_t			pos_in,
1139	struct file		*file_out,
1140	loff_t			pos_out,
1141	loff_t			len,
1142	unsigned int		remap_flags)
1143{
1144	struct inode		*inode_in = file_inode(file_in);
1145	struct xfs_inode	*src = XFS_I(inode_in);
1146	struct inode		*inode_out = file_inode(file_out);
1147	struct xfs_inode	*dest = XFS_I(inode_out);
1148	struct xfs_mount	*mp = src->i_mount;
1149	loff_t			remapped = 0;
1150	xfs_extlen_t		cowextsize;
1151	int			ret;
1152
1153	if (remap_flags & ~(REMAP_FILE_DEDUP | REMAP_FILE_ADVISORY))
1154		return -EINVAL;
1155
1156	if (!xfs_has_reflink(mp))
1157		return -EOPNOTSUPP;
1158
1159	if (xfs_is_shutdown(mp))
1160		return -EIO;
1161
1162	/* Prepare and then clone file data. */
1163	ret = xfs_reflink_remap_prep(file_in, pos_in, file_out, pos_out,
1164			&len, remap_flags);
1165	if (ret || len == 0)
1166		return ret;
1167
1168	trace_xfs_reflink_remap_range(src, pos_in, len, dest, pos_out);
1169
1170	ret = xfs_reflink_remap_blocks(src, pos_in, dest, pos_out, len,
1171			&remapped);
1172	if (ret)
1173		goto out_unlock;
1174
1175	/*
1176	 * Carry the cowextsize hint from src to dest if we're sharing the
1177	 * entire source file to the entire destination file, the source file
1178	 * has a cowextsize hint, and the destination file does not.
1179	 */
1180	cowextsize = 0;
1181	if (pos_in == 0 && len == i_size_read(inode_in) &&
1182	    (src->i_diflags2 & XFS_DIFLAG2_COWEXTSIZE) &&
1183	    pos_out == 0 && len >= i_size_read(inode_out) &&
1184	    !(dest->i_diflags2 & XFS_DIFLAG2_COWEXTSIZE))
1185		cowextsize = src->i_cowextsize;
1186
1187	ret = xfs_reflink_update_dest(dest, pos_out + len, cowextsize,
1188			remap_flags);
1189	if (ret)
1190		goto out_unlock;
1191
1192	if (xfs_file_sync_writes(file_in) || xfs_file_sync_writes(file_out))
1193		xfs_log_force_inode(dest);
1194out_unlock:
1195	xfs_iunlock2_io_mmap(src, dest);
1196	if (ret)
1197		trace_xfs_reflink_remap_range_error(dest, ret, _RET_IP_);
1198	return remapped > 0 ? remapped : ret;
1199}
1200
1201STATIC int
1202xfs_file_open(
1203	struct inode	*inode,
1204	struct file	*file)
1205{
1206	if (!(file->f_flags & O_LARGEFILE) && i_size_read(inode) > MAX_NON_LFS)
1207		return -EFBIG;
1208	if (xfs_is_shutdown(XFS_M(inode->i_sb)))
1209		return -EIO;
1210	file->f_mode |= FMODE_NOWAIT | FMODE_BUF_RASYNC;
1211	return 0;
1212}
1213
1214STATIC int
1215xfs_dir_open(
1216	struct inode	*inode,
1217	struct file	*file)
1218{
1219	struct xfs_inode *ip = XFS_I(inode);
1220	int		mode;
1221	int		error;
1222
1223	error = xfs_file_open(inode, file);
1224	if (error)
1225		return error;
1226
1227	/*
1228	 * If there are any blocks, read-ahead block 0 as we're almost
1229	 * certain to have the next operation be a read there.
1230	 */
1231	mode = xfs_ilock_data_map_shared(ip);
1232	if (ip->i_df.if_nextents > 0)
1233		error = xfs_dir3_data_readahead(ip, 0, 0);
1234	xfs_iunlock(ip, mode);
1235	return error;
1236}
1237
1238STATIC int
1239xfs_file_release(
1240	struct inode	*inode,
1241	struct file	*filp)
1242{
1243	return xfs_release(XFS_I(inode));
1244}
1245
1246STATIC int
1247xfs_file_readdir(
1248	struct file	*file,
1249	struct dir_context *ctx)
1250{
1251	struct inode	*inode = file_inode(file);
1252	xfs_inode_t	*ip = XFS_I(inode);
1253	size_t		bufsize;
1254
1255	/*
1256	 * The Linux API doesn't pass down the total size of the buffer
1257	 * we read into down to the filesystem.  With the filldir concept
1258	 * it's not needed for correct information, but the XFS dir2 leaf
1259	 * code wants an estimate of the buffer size to calculate it's
1260	 * readahead window and size the buffers used for mapping to
1261	 * physical blocks.
1262	 *
1263	 * Try to give it an estimate that's good enough, maybe at some
1264	 * point we can change the ->readdir prototype to include the
1265	 * buffer size.  For now we use the current glibc buffer size.
1266	 */
1267	bufsize = (size_t)min_t(loff_t, XFS_READDIR_BUFSIZE, ip->i_disk_size);
1268
1269	return xfs_readdir(NULL, ip, ctx, bufsize);
1270}
1271
1272STATIC loff_t
1273xfs_file_llseek(
1274	struct file	*file,
1275	loff_t		offset,
1276	int		whence)
1277{
1278	struct inode		*inode = file->f_mapping->host;
1279
1280	if (xfs_is_shutdown(XFS_I(inode)->i_mount))
1281		return -EIO;
1282
1283	switch (whence) {
1284	default:
1285		return generic_file_llseek(file, offset, whence);
1286	case SEEK_HOLE:
1287		offset = iomap_seek_hole(inode, offset, &xfs_seek_iomap_ops);
1288		break;
1289	case SEEK_DATA:
1290		offset = iomap_seek_data(inode, offset, &xfs_seek_iomap_ops);
1291		break;
1292	}
1293
1294	if (offset < 0)
1295		return offset;
1296	return vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
1297}
1298
1299/*
1300 * Locking for serialisation of IO during page faults. This results in a lock
1301 * ordering of:
1302 *
1303 * mmap_lock (MM)
1304 *   sb_start_pagefault(vfs, freeze)
1305 *     i_mmaplock (XFS - truncate serialisation)
1306 *       page_lock (MM)
1307 *         i_lock (XFS - extent map serialisation)
1308 */
1309static vm_fault_t
1310__xfs_filemap_fault(
1311	struct vm_fault		*vmf,
1312	enum page_entry_size	pe_size,
1313	bool			write_fault)
1314{
1315	struct inode		*inode = file_inode(vmf->vma->vm_file);
1316	struct xfs_inode	*ip = XFS_I(inode);
1317	vm_fault_t		ret;
1318
1319	trace_xfs_filemap_fault(ip, pe_size, write_fault);
1320
1321	if (write_fault) {
1322		sb_start_pagefault(inode->i_sb);
1323		file_update_time(vmf->vma->vm_file);
1324	}
1325
1326	xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
1327	if (IS_DAX(inode)) {
1328		pfn_t pfn;
1329
1330		ret = dax_iomap_fault(vmf, pe_size, &pfn, NULL,
1331				(write_fault && !vmf->cow_page) ?
1332				 &xfs_direct_write_iomap_ops :
1333				 &xfs_read_iomap_ops);
1334		if (ret & VM_FAULT_NEEDDSYNC)
1335			ret = dax_finish_sync_fault(vmf, pe_size, pfn);
1336	} else {
1337		if (write_fault)
1338			ret = iomap_page_mkwrite(vmf,
1339					&xfs_buffered_write_iomap_ops);
1340		else
1341			ret = filemap_fault(vmf);
1342	}
1343	xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
1344
1345	if (write_fault)
1346		sb_end_pagefault(inode->i_sb);
1347	return ret;
1348}
1349
1350static inline bool
1351xfs_is_write_fault(
1352	struct vm_fault		*vmf)
1353{
1354	return (vmf->flags & FAULT_FLAG_WRITE) &&
1355	       (vmf->vma->vm_flags & VM_SHARED);
1356}
1357
1358static vm_fault_t
1359xfs_filemap_fault(
1360	struct vm_fault		*vmf)
1361{
1362	/* DAX can shortcut the normal fault path on write faults! */
1363	return __xfs_filemap_fault(vmf, PE_SIZE_PTE,
1364			IS_DAX(file_inode(vmf->vma->vm_file)) &&
1365			xfs_is_write_fault(vmf));
1366}
1367
1368static vm_fault_t
1369xfs_filemap_huge_fault(
1370	struct vm_fault		*vmf,
1371	enum page_entry_size	pe_size)
1372{
1373	if (!IS_DAX(file_inode(vmf->vma->vm_file)))
1374		return VM_FAULT_FALLBACK;
1375
1376	/* DAX can shortcut the normal fault path on write faults! */
1377	return __xfs_filemap_fault(vmf, pe_size,
1378			xfs_is_write_fault(vmf));
1379}
1380
1381static vm_fault_t
1382xfs_filemap_page_mkwrite(
1383	struct vm_fault		*vmf)
1384{
1385	return __xfs_filemap_fault(vmf, PE_SIZE_PTE, true);
1386}
1387
1388/*
1389 * pfn_mkwrite was originally intended to ensure we capture time stamp updates
1390 * on write faults. In reality, it needs to serialise against truncate and
1391 * prepare memory for writing so handle is as standard write fault.
1392 */
1393static vm_fault_t
1394xfs_filemap_pfn_mkwrite(
1395	struct vm_fault		*vmf)
1396{
1397
1398	return __xfs_filemap_fault(vmf, PE_SIZE_PTE, true);
1399}
1400
1401static vm_fault_t
1402xfs_filemap_map_pages(
1403	struct vm_fault		*vmf,
1404	pgoff_t			start_pgoff,
1405	pgoff_t			end_pgoff)
1406{
1407	struct inode		*inode = file_inode(vmf->vma->vm_file);
1408	vm_fault_t ret;
1409
1410	xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
1411	ret = filemap_map_pages(vmf, start_pgoff, end_pgoff);
1412	xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
1413	return ret;
1414}
1415
1416static const struct vm_operations_struct xfs_file_vm_ops = {
1417	.fault		= xfs_filemap_fault,
1418	.huge_fault	= xfs_filemap_huge_fault,
1419	.map_pages	= xfs_filemap_map_pages,
1420	.page_mkwrite	= xfs_filemap_page_mkwrite,
1421	.pfn_mkwrite	= xfs_filemap_pfn_mkwrite,
1422};
1423
1424STATIC int
1425xfs_file_mmap(
1426	struct file		*file,
1427	struct vm_area_struct	*vma)
1428{
1429	struct inode		*inode = file_inode(file);
1430	struct xfs_buftarg	*target = xfs_inode_buftarg(XFS_I(inode));
1431
1432	/*
1433	 * We don't support synchronous mappings for non-DAX files and
1434	 * for DAX files if underneath dax_device is not synchronous.
1435	 */
1436	if (!daxdev_mapping_supported(vma, target->bt_daxdev))
1437		return -EOPNOTSUPP;
1438
1439	file_accessed(file);
1440	vma->vm_ops = &xfs_file_vm_ops;
1441	if (IS_DAX(inode))
1442		vma->vm_flags |= VM_HUGEPAGE;
1443	return 0;
1444}
1445
1446const struct file_operations xfs_file_operations = {
1447	.llseek		= xfs_file_llseek,
1448	.read_iter	= xfs_file_read_iter,
1449	.write_iter	= xfs_file_write_iter,
1450	.splice_read	= generic_file_splice_read,
1451	.splice_write	= iter_file_splice_write,
1452	.iopoll		= iomap_dio_iopoll,
1453	.unlocked_ioctl	= xfs_file_ioctl,
1454#ifdef CONFIG_COMPAT
1455	.compat_ioctl	= xfs_file_compat_ioctl,
1456#endif
1457	.mmap		= xfs_file_mmap,
1458	.mmap_supported_flags = MAP_SYNC,
1459	.open		= xfs_file_open,
1460	.release	= xfs_file_release,
1461	.fsync		= xfs_file_fsync,
1462	.get_unmapped_area = thp_get_unmapped_area,
1463	.fallocate	= xfs_file_fallocate,
1464	.fadvise	= xfs_file_fadvise,
1465	.remap_file_range = xfs_file_remap_range,
1466};
1467
1468const struct file_operations xfs_dir_file_operations = {
1469	.open		= xfs_dir_open,
1470	.read		= generic_read_dir,
1471	.iterate_shared	= xfs_file_readdir,
1472	.llseek		= generic_file_llseek,
1473	.unlocked_ioctl	= xfs_file_ioctl,
1474#ifdef CONFIG_COMPAT
1475	.compat_ioctl	= xfs_file_compat_ioctl,
1476#endif
1477	.fsync		= xfs_dir_fsync,
1478};
1479