1/*
2 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
3 * All Rights Reserved.
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it would be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write the Free Software Foundation,
16 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
17 */
18#include "xfs.h"
19#include "xfs_bit.h"
20#include "xfs_log.h"
21#include "xfs_inum.h"
22#include "xfs_sb.h"
23#include "xfs_ag.h"
24#include "xfs_dir2.h"
25#include "xfs_trans.h"
26#include "xfs_dmapi.h"
27#include "xfs_mount.h"
28#include "xfs_bmap_btree.h"
29#include "xfs_alloc_btree.h"
30#include "xfs_ialloc_btree.h"
31#include "xfs_dir2_sf.h"
32#include "xfs_attr_sf.h"
33#include "xfs_dinode.h"
34#include "xfs_inode.h"
35#include "xfs_alloc.h"
36#include "xfs_btree.h"
37#include "xfs_error.h"
38#include "xfs_rw.h"
39#include "xfs_iomap.h"
40#include <linux/mpage.h>
41#include <linux/pagevec.h>
42#include <linux/writeback.h>
43
44STATIC void
45xfs_count_page_state(
46	struct page		*page,
47	int			*delalloc,
48	int			*unmapped,
49	int			*unwritten)
50{
51	struct buffer_head	*bh, *head;
52
53	*delalloc = *unmapped = *unwritten = 0;
54
55	bh = head = page_buffers(page);
56	do {
57		if (buffer_uptodate(bh) && !buffer_mapped(bh))
58			(*unmapped) = 1;
59		else if (buffer_unwritten(bh))
60			(*unwritten) = 1;
61		else if (buffer_delay(bh))
62			(*delalloc) = 1;
63	} while ((bh = bh->b_this_page) != head);
64}
65
66#if defined(XFS_RW_TRACE)
67void
68xfs_page_trace(
69	int		tag,
70	struct inode	*inode,
71	struct page	*page,
72	unsigned long	pgoff)
73{
74	xfs_inode_t	*ip;
75	bhv_vnode_t	*vp = vn_from_inode(inode);
76	loff_t		isize = i_size_read(inode);
77	loff_t		offset = page_offset(page);
78	int		delalloc = -1, unmapped = -1, unwritten = -1;
79
80	if (page_has_buffers(page))
81		xfs_count_page_state(page, &delalloc, &unmapped, &unwritten);
82
83	ip = xfs_vtoi(vp);
84	if (!ip->i_rwtrace)
85		return;
86
87	ktrace_enter(ip->i_rwtrace,
88		(void *)((unsigned long)tag),
89		(void *)ip,
90		(void *)inode,
91		(void *)page,
92		(void *)pgoff,
93		(void *)((unsigned long)((ip->i_d.di_size >> 32) & 0xffffffff)),
94		(void *)((unsigned long)(ip->i_d.di_size & 0xffffffff)),
95		(void *)((unsigned long)((isize >> 32) & 0xffffffff)),
96		(void *)((unsigned long)(isize & 0xffffffff)),
97		(void *)((unsigned long)((offset >> 32) & 0xffffffff)),
98		(void *)((unsigned long)(offset & 0xffffffff)),
99		(void *)((unsigned long)delalloc),
100		(void *)((unsigned long)unmapped),
101		(void *)((unsigned long)unwritten),
102		(void *)((unsigned long)current_pid()),
103		(void *)NULL);
104}
105#else
106#define xfs_page_trace(tag, inode, page, pgoff)
107#endif
108
109/*
110 * Schedule IO completion handling on a xfsdatad if this was
111 * the final hold on this ioend.
112 */
113STATIC void
114xfs_finish_ioend(
115	xfs_ioend_t		*ioend)
116{
117	if (atomic_dec_and_test(&ioend->io_remaining))
118		queue_work(xfsdatad_workqueue, &ioend->io_work);
119}
120
121/*
122 * We're now finished for good with this ioend structure.
123 * Update the page state via the associated buffer_heads,
124 * release holds on the inode and bio, and finally free
125 * up memory.  Do not use the ioend after this.
126 */
127STATIC void
128xfs_destroy_ioend(
129	xfs_ioend_t		*ioend)
130{
131	struct buffer_head	*bh, *next;
132
133	for (bh = ioend->io_buffer_head; bh; bh = next) {
134		next = bh->b_private;
135		bh->b_end_io(bh, !ioend->io_error);
136	}
137	if (unlikely(ioend->io_error))
138		vn_ioerror(ioend->io_vnode, ioend->io_error, __FILE__,__LINE__);
139	vn_iowake(ioend->io_vnode);
140	mempool_free(ioend, xfs_ioend_pool);
141}
142
143/*
144 * Update on-disk file size now that data has been written to disk.
145 * The current in-memory file size is i_size.  If a write is beyond
146 * eof io_new_size will be the intended file size until i_size is
147 * updated.  If this write does not extend all the way to the valid
148 * file size then restrict this update to the end of the write.
149 */
150STATIC void
151xfs_setfilesize(
152	xfs_ioend_t		*ioend)
153{
154	xfs_inode_t		*ip;
155	xfs_fsize_t		isize;
156	xfs_fsize_t		bsize;
157
158	ip = xfs_vtoi(ioend->io_vnode);
159
160	ASSERT((ip->i_d.di_mode & S_IFMT) == S_IFREG);
161	ASSERT(ioend->io_type != IOMAP_READ);
162
163	if (unlikely(ioend->io_error))
164		return;
165
166	bsize = ioend->io_offset + ioend->io_size;
167
168	xfs_ilock(ip, XFS_ILOCK_EXCL);
169
170	isize = MAX(ip->i_size, ip->i_iocore.io_new_size);
171	isize = MIN(isize, bsize);
172
173	if (ip->i_d.di_size < isize) {
174		ip->i_d.di_size = isize;
175		ip->i_update_core = 1;
176		ip->i_update_size = 1;
177	}
178
179	xfs_iunlock(ip, XFS_ILOCK_EXCL);
180}
181
182/*
183 * Buffered IO write completion for delayed allocate extents.
184 */
185STATIC void
186xfs_end_bio_delalloc(
187	struct work_struct	*work)
188{
189	xfs_ioend_t		*ioend =
190		container_of(work, xfs_ioend_t, io_work);
191
192	xfs_setfilesize(ioend);
193	xfs_destroy_ioend(ioend);
194}
195
196/*
197 * Buffered IO write completion for regular, written extents.
198 */
199STATIC void
200xfs_end_bio_written(
201	struct work_struct	*work)
202{
203	xfs_ioend_t		*ioend =
204		container_of(work, xfs_ioend_t, io_work);
205
206	xfs_setfilesize(ioend);
207	xfs_destroy_ioend(ioend);
208}
209
210/*
211 * IO write completion for unwritten extents.
212 *
213 * Issue transactions to convert a buffer range from unwritten
214 * to written extents.
215 */
216STATIC void
217xfs_end_bio_unwritten(
218	struct work_struct	*work)
219{
220	xfs_ioend_t		*ioend =
221		container_of(work, xfs_ioend_t, io_work);
222	bhv_vnode_t		*vp = ioend->io_vnode;
223	xfs_off_t		offset = ioend->io_offset;
224	size_t			size = ioend->io_size;
225
226	if (likely(!ioend->io_error)) {
227		bhv_vop_bmap(vp, offset, size, BMAPI_UNWRITTEN, NULL, NULL);
228		xfs_setfilesize(ioend);
229	}
230	xfs_destroy_ioend(ioend);
231}
232
233/*
234 * IO read completion for regular, written extents.
235 */
236STATIC void
237xfs_end_bio_read(
238	struct work_struct	*work)
239{
240	xfs_ioend_t		*ioend =
241		container_of(work, xfs_ioend_t, io_work);
242
243	xfs_destroy_ioend(ioend);
244}
245
246/*
247 * Allocate and initialise an IO completion structure.
248 * We need to track unwritten extent write completion here initially.
249 * We'll need to extend this for updating the ondisk inode size later
250 * (vs. incore size).
251 */
252STATIC xfs_ioend_t *
253xfs_alloc_ioend(
254	struct inode		*inode,
255	unsigned int		type)
256{
257	xfs_ioend_t		*ioend;
258
259	ioend = mempool_alloc(xfs_ioend_pool, GFP_NOFS);
260
261	/*
262	 * Set the count to 1 initially, which will prevent an I/O
263	 * completion callback from happening before we have started
264	 * all the I/O from calling the completion routine too early.
265	 */
266	atomic_set(&ioend->io_remaining, 1);
267	ioend->io_error = 0;
268	ioend->io_list = NULL;
269	ioend->io_type = type;
270	ioend->io_vnode = vn_from_inode(inode);
271	ioend->io_buffer_head = NULL;
272	ioend->io_buffer_tail = NULL;
273	atomic_inc(&ioend->io_vnode->v_iocount);
274	ioend->io_offset = 0;
275	ioend->io_size = 0;
276
277	if (type == IOMAP_UNWRITTEN)
278		INIT_WORK(&ioend->io_work, xfs_end_bio_unwritten);
279	else if (type == IOMAP_DELAY)
280		INIT_WORK(&ioend->io_work, xfs_end_bio_delalloc);
281	else if (type == IOMAP_READ)
282		INIT_WORK(&ioend->io_work, xfs_end_bio_read);
283	else
284		INIT_WORK(&ioend->io_work, xfs_end_bio_written);
285
286	return ioend;
287}
288
289STATIC int
290xfs_map_blocks(
291	struct inode		*inode,
292	loff_t			offset,
293	ssize_t			count,
294	xfs_iomap_t		*mapp,
295	int			flags)
296{
297	bhv_vnode_t		*vp = vn_from_inode(inode);
298	int			error, nmaps = 1;
299
300	error = bhv_vop_bmap(vp, offset, count, flags, mapp, &nmaps);
301	if (!error && (flags & (BMAPI_WRITE|BMAPI_ALLOCATE)))
302		VMODIFY(vp);
303	return -error;
304}
305
306STATIC_INLINE int
307xfs_iomap_valid(
308	xfs_iomap_t		*iomapp,
309	loff_t			offset)
310{
311	return offset >= iomapp->iomap_offset &&
312		offset < iomapp->iomap_offset + iomapp->iomap_bsize;
313}
314
315/*
316 * BIO completion handler for buffered IO.
317 */
318STATIC int
319xfs_end_bio(
320	struct bio		*bio,
321	unsigned int		bytes_done,
322	int			error)
323{
324	xfs_ioend_t		*ioend = bio->bi_private;
325
326	if (bio->bi_size)
327		return 1;
328
329	ASSERT(atomic_read(&bio->bi_cnt) >= 1);
330	ioend->io_error = test_bit(BIO_UPTODATE, &bio->bi_flags) ? 0 : error;
331
332	/* Toss bio and pass work off to an xfsdatad thread */
333	bio->bi_private = NULL;
334	bio->bi_end_io = NULL;
335	bio_put(bio);
336
337	xfs_finish_ioend(ioend);
338	return 0;
339}
340
341STATIC void
342xfs_submit_ioend_bio(
343	xfs_ioend_t	*ioend,
344	struct bio	*bio)
345{
346	atomic_inc(&ioend->io_remaining);
347
348	bio->bi_private = ioend;
349	bio->bi_end_io = xfs_end_bio;
350
351	submit_bio(WRITE, bio);
352	ASSERT(!bio_flagged(bio, BIO_EOPNOTSUPP));
353	bio_put(bio);
354}
355
356STATIC struct bio *
357xfs_alloc_ioend_bio(
358	struct buffer_head	*bh)
359{
360	struct bio		*bio;
361	int			nvecs = bio_get_nr_vecs(bh->b_bdev);
362
363	do {
364		bio = bio_alloc(GFP_NOIO, nvecs);
365		nvecs >>= 1;
366	} while (!bio);
367
368	ASSERT(bio->bi_private == NULL);
369	bio->bi_sector = bh->b_blocknr * (bh->b_size >> 9);
370	bio->bi_bdev = bh->b_bdev;
371	bio_get(bio);
372	return bio;
373}
374
375STATIC void
376xfs_start_buffer_writeback(
377	struct buffer_head	*bh)
378{
379	ASSERT(buffer_mapped(bh));
380	ASSERT(buffer_locked(bh));
381	ASSERT(!buffer_delay(bh));
382	ASSERT(!buffer_unwritten(bh));
383
384	mark_buffer_async_write(bh);
385	set_buffer_uptodate(bh);
386	clear_buffer_dirty(bh);
387}
388
389STATIC void
390xfs_start_page_writeback(
391	struct page		*page,
392	struct writeback_control *wbc,
393	int			clear_dirty,
394	int			buffers)
395{
396	ASSERT(PageLocked(page));
397	ASSERT(!PageWriteback(page));
398	if (clear_dirty)
399		clear_page_dirty_for_io(page);
400	set_page_writeback(page);
401	unlock_page(page);
402	if (!buffers) {
403		end_page_writeback(page);
404		wbc->pages_skipped++;	/* We didn't write this page */
405	}
406}
407
408static inline int bio_add_buffer(struct bio *bio, struct buffer_head *bh)
409{
410	return bio_add_page(bio, bh->b_page, bh->b_size, bh_offset(bh));
411}
412
413/*
414 * Submit all of the bios for all of the ioends we have saved up, covering the
415 * initial writepage page and also any probed pages.
416 *
417 * Because we may have multiple ioends spanning a page, we need to start
418 * writeback on all the buffers before we submit them for I/O. If we mark the
419 * buffers as we got, then we can end up with a page that only has buffers
420 * marked async write and I/O complete on can occur before we mark the other
421 * buffers async write.
422 *
423 * The end result of this is that we trip a bug in end_page_writeback() because
424 * we call it twice for the one page as the code in end_buffer_async_write()
425 * assumes that all buffers on the page are started at the same time.
426 *
427 * The fix is two passes across the ioend list - one to start writeback on the
428 * buffer_heads, and then submit them for I/O on the second pass.
429 */
430STATIC void
431xfs_submit_ioend(
432	xfs_ioend_t		*ioend)
433{
434	xfs_ioend_t		*head = ioend;
435	xfs_ioend_t		*next;
436	struct buffer_head	*bh;
437	struct bio		*bio;
438	sector_t		lastblock = 0;
439
440	/* Pass 1 - start writeback */
441	do {
442		next = ioend->io_list;
443		for (bh = ioend->io_buffer_head; bh; bh = bh->b_private) {
444			xfs_start_buffer_writeback(bh);
445		}
446	} while ((ioend = next) != NULL);
447
448	/* Pass 2 - submit I/O */
449	ioend = head;
450	do {
451		next = ioend->io_list;
452		bio = NULL;
453
454		for (bh = ioend->io_buffer_head; bh; bh = bh->b_private) {
455
456			if (!bio) {
457 retry:
458				bio = xfs_alloc_ioend_bio(bh);
459			} else if (bh->b_blocknr != lastblock + 1) {
460				xfs_submit_ioend_bio(ioend, bio);
461				goto retry;
462			}
463
464			if (bio_add_buffer(bio, bh) != bh->b_size) {
465				xfs_submit_ioend_bio(ioend, bio);
466				goto retry;
467			}
468
469			lastblock = bh->b_blocknr;
470		}
471		if (bio)
472			xfs_submit_ioend_bio(ioend, bio);
473		xfs_finish_ioend(ioend);
474	} while ((ioend = next) != NULL);
475}
476
477/*
478 * Cancel submission of all buffer_heads so far in this endio.
479 * Toss the endio too.  Only ever called for the initial page
480 * in a writepage request, so only ever one page.
481 */
482STATIC void
483xfs_cancel_ioend(
484	xfs_ioend_t		*ioend)
485{
486	xfs_ioend_t		*next;
487	struct buffer_head	*bh, *next_bh;
488
489	do {
490		next = ioend->io_list;
491		bh = ioend->io_buffer_head;
492		do {
493			next_bh = bh->b_private;
494			clear_buffer_async_write(bh);
495			unlock_buffer(bh);
496		} while ((bh = next_bh) != NULL);
497
498		vn_iowake(ioend->io_vnode);
499		mempool_free(ioend, xfs_ioend_pool);
500	} while ((ioend = next) != NULL);
501}
502
503/*
504 * Test to see if we've been building up a completion structure for
505 * earlier buffers -- if so, we try to append to this ioend if we
506 * can, otherwise we finish off any current ioend and start another.
507 * Return true if we've finished the given ioend.
508 */
509STATIC void
510xfs_add_to_ioend(
511	struct inode		*inode,
512	struct buffer_head	*bh,
513	xfs_off_t		offset,
514	unsigned int		type,
515	xfs_ioend_t		**result,
516	int			need_ioend)
517{
518	xfs_ioend_t		*ioend = *result;
519
520	if (!ioend || need_ioend || type != ioend->io_type) {
521		xfs_ioend_t	*previous = *result;
522
523		ioend = xfs_alloc_ioend(inode, type);
524		ioend->io_offset = offset;
525		ioend->io_buffer_head = bh;
526		ioend->io_buffer_tail = bh;
527		if (previous)
528			previous->io_list = ioend;
529		*result = ioend;
530	} else {
531		ioend->io_buffer_tail->b_private = bh;
532		ioend->io_buffer_tail = bh;
533	}
534
535	bh->b_private = NULL;
536	ioend->io_size += bh->b_size;
537}
538
539STATIC void
540xfs_map_buffer(
541	struct buffer_head	*bh,
542	xfs_iomap_t		*mp,
543	xfs_off_t		offset,
544	uint			block_bits)
545{
546	sector_t		bn;
547
548	ASSERT(mp->iomap_bn != IOMAP_DADDR_NULL);
549
550	bn = (mp->iomap_bn >> (block_bits - BBSHIFT)) +
551	      ((offset - mp->iomap_offset) >> block_bits);
552
553	ASSERT(bn || (mp->iomap_flags & IOMAP_REALTIME));
554
555	bh->b_blocknr = bn;
556	set_buffer_mapped(bh);
557}
558
559STATIC void
560xfs_map_at_offset(
561	struct buffer_head	*bh,
562	loff_t			offset,
563	int			block_bits,
564	xfs_iomap_t		*iomapp)
565{
566	ASSERT(!(iomapp->iomap_flags & IOMAP_HOLE));
567	ASSERT(!(iomapp->iomap_flags & IOMAP_DELAY));
568
569	lock_buffer(bh);
570	xfs_map_buffer(bh, iomapp, offset, block_bits);
571	bh->b_bdev = iomapp->iomap_target->bt_bdev;
572	set_buffer_mapped(bh);
573	clear_buffer_delay(bh);
574	clear_buffer_unwritten(bh);
575}
576
577/*
578 * Look for a page at index that is suitable for clustering.
579 */
580STATIC unsigned int
581xfs_probe_page(
582	struct page		*page,
583	unsigned int		pg_offset,
584	int			mapped)
585{
586	int			ret = 0;
587
588	if (PageWriteback(page))
589		return 0;
590
591	if (page->mapping && PageDirty(page)) {
592		if (page_has_buffers(page)) {
593			struct buffer_head	*bh, *head;
594
595			bh = head = page_buffers(page);
596			do {
597				if (!buffer_uptodate(bh))
598					break;
599				if (mapped != buffer_mapped(bh))
600					break;
601				ret += bh->b_size;
602				if (ret >= pg_offset)
603					break;
604			} while ((bh = bh->b_this_page) != head);
605		} else
606			ret = mapped ? 0 : PAGE_CACHE_SIZE;
607	}
608
609	return ret;
610}
611
612STATIC size_t
613xfs_probe_cluster(
614	struct inode		*inode,
615	struct page		*startpage,
616	struct buffer_head	*bh,
617	struct buffer_head	*head,
618	int			mapped)
619{
620	struct pagevec		pvec;
621	pgoff_t			tindex, tlast, tloff;
622	size_t			total = 0;
623	int			done = 0, i;
624
625	/* First sum forwards in this page */
626	do {
627		if (!buffer_uptodate(bh) || (mapped != buffer_mapped(bh)))
628			return total;
629		total += bh->b_size;
630	} while ((bh = bh->b_this_page) != head);
631
632	/* if we reached the end of the page, sum forwards in following pages */
633	tlast = i_size_read(inode) >> PAGE_CACHE_SHIFT;
634	tindex = startpage->index + 1;
635
636	/* Prune this back to avoid pathological behavior */
637	tloff = min(tlast, startpage->index + 64);
638
639	pagevec_init(&pvec, 0);
640	while (!done && tindex <= tloff) {
641		unsigned len = min_t(pgoff_t, PAGEVEC_SIZE, tlast - tindex + 1);
642
643		if (!pagevec_lookup(&pvec, inode->i_mapping, tindex, len))
644			break;
645
646		for (i = 0; i < pagevec_count(&pvec); i++) {
647			struct page *page = pvec.pages[i];
648			size_t pg_offset, len = 0;
649
650			if (tindex == tlast) {
651				pg_offset =
652				    i_size_read(inode) & (PAGE_CACHE_SIZE - 1);
653				if (!pg_offset) {
654					done = 1;
655					break;
656				}
657			} else
658				pg_offset = PAGE_CACHE_SIZE;
659
660			if (page->index == tindex && !TestSetPageLocked(page)) {
661				len = xfs_probe_page(page, pg_offset, mapped);
662				unlock_page(page);
663			}
664
665			if (!len) {
666				done = 1;
667				break;
668			}
669
670			total += len;
671			tindex++;
672		}
673
674		pagevec_release(&pvec);
675		cond_resched();
676	}
677
678	return total;
679}
680
681/*
682 * Test if a given page is suitable for writing as part of an unwritten
683 * or delayed allocate extent.
684 */
685STATIC int
686xfs_is_delayed_page(
687	struct page		*page,
688	unsigned int		type)
689{
690	if (PageWriteback(page))
691		return 0;
692
693	if (page->mapping && page_has_buffers(page)) {
694		struct buffer_head	*bh, *head;
695		int			acceptable = 0;
696
697		bh = head = page_buffers(page);
698		do {
699			if (buffer_unwritten(bh))
700				acceptable = (type == IOMAP_UNWRITTEN);
701			else if (buffer_delay(bh))
702				acceptable = (type == IOMAP_DELAY);
703			else if (buffer_dirty(bh) && buffer_mapped(bh))
704				acceptable = (type == IOMAP_NEW);
705			else
706				break;
707		} while ((bh = bh->b_this_page) != head);
708
709		if (acceptable)
710			return 1;
711	}
712
713	return 0;
714}
715
716/*
717 * Allocate & map buffers for page given the extent map. Write it out.
718 * except for the original page of a writepage, this is called on
719 * delalloc/unwritten pages only, for the original page it is possible
720 * that the page has no mapping at all.
721 */
722STATIC int
723xfs_convert_page(
724	struct inode		*inode,
725	struct page		*page,
726	loff_t			tindex,
727	xfs_iomap_t		*mp,
728	xfs_ioend_t		**ioendp,
729	struct writeback_control *wbc,
730	int			startio,
731	int			all_bh)
732{
733	struct buffer_head	*bh, *head;
734	xfs_off_t		end_offset;
735	unsigned long		p_offset;
736	unsigned int		type;
737	int			bbits = inode->i_blkbits;
738	int			len, page_dirty;
739	int			count = 0, done = 0, uptodate = 1;
740 	xfs_off_t		offset = page_offset(page);
741
742	if (page->index != tindex)
743		goto fail;
744	if (TestSetPageLocked(page))
745		goto fail;
746	if (PageWriteback(page))
747		goto fail_unlock_page;
748	if (page->mapping != inode->i_mapping)
749		goto fail_unlock_page;
750	if (!xfs_is_delayed_page(page, (*ioendp)->io_type))
751		goto fail_unlock_page;
752
753	/*
754	 * page_dirty is initially a count of buffers on the page before
755	 * EOF and is decremented as we move each into a cleanable state.
756	 *
757	 * Derivation:
758	 *
759	 * End offset is the highest offset that this page should represent.
760	 * If we are on the last page, (end_offset & (PAGE_CACHE_SIZE - 1))
761	 * will evaluate non-zero and be less than PAGE_CACHE_SIZE and
762	 * hence give us the correct page_dirty count. On any other page,
763	 * it will be zero and in that case we need page_dirty to be the
764	 * count of buffers on the page.
765	 */
766	end_offset = min_t(unsigned long long,
767			(xfs_off_t)(page->index + 1) << PAGE_CACHE_SHIFT,
768			i_size_read(inode));
769
770	len = 1 << inode->i_blkbits;
771	p_offset = min_t(unsigned long, end_offset & (PAGE_CACHE_SIZE - 1),
772					PAGE_CACHE_SIZE);
773	p_offset = p_offset ? roundup(p_offset, len) : PAGE_CACHE_SIZE;
774	page_dirty = p_offset / len;
775
776	bh = head = page_buffers(page);
777	do {
778		if (offset >= end_offset)
779			break;
780		if (!buffer_uptodate(bh))
781			uptodate = 0;
782		if (!(PageUptodate(page) || buffer_uptodate(bh))) {
783			done = 1;
784			continue;
785		}
786
787		if (buffer_unwritten(bh) || buffer_delay(bh)) {
788			if (buffer_unwritten(bh))
789				type = IOMAP_UNWRITTEN;
790			else
791				type = IOMAP_DELAY;
792
793			if (!xfs_iomap_valid(mp, offset)) {
794				done = 1;
795				continue;
796			}
797
798			ASSERT(!(mp->iomap_flags & IOMAP_HOLE));
799			ASSERT(!(mp->iomap_flags & IOMAP_DELAY));
800
801			xfs_map_at_offset(bh, offset, bbits, mp);
802			if (startio) {
803				xfs_add_to_ioend(inode, bh, offset,
804						type, ioendp, done);
805			} else {
806				set_buffer_dirty(bh);
807				unlock_buffer(bh);
808				mark_buffer_dirty(bh);
809			}
810			page_dirty--;
811			count++;
812		} else {
813			type = IOMAP_NEW;
814			if (buffer_mapped(bh) && all_bh && startio) {
815				lock_buffer(bh);
816				xfs_add_to_ioend(inode, bh, offset,
817						type, ioendp, done);
818				count++;
819				page_dirty--;
820			} else {
821				done = 1;
822			}
823		}
824	} while (offset += len, (bh = bh->b_this_page) != head);
825
826	if (uptodate && bh == head)
827		SetPageUptodate(page);
828
829	if (startio) {
830		if (count) {
831			struct backing_dev_info *bdi;
832
833			bdi = inode->i_mapping->backing_dev_info;
834			wbc->nr_to_write--;
835			if (bdi_write_congested(bdi)) {
836				wbc->encountered_congestion = 1;
837				done = 1;
838			} else if (wbc->nr_to_write <= 0) {
839				done = 1;
840			}
841		}
842		xfs_start_page_writeback(page, wbc, !page_dirty, count);
843	}
844
845	return done;
846 fail_unlock_page:
847	unlock_page(page);
848 fail:
849	return 1;
850}
851
852/*
853 * Convert & write out a cluster of pages in the same extent as defined
854 * by mp and following the start page.
855 */
856STATIC void
857xfs_cluster_write(
858	struct inode		*inode,
859	pgoff_t			tindex,
860	xfs_iomap_t		*iomapp,
861	xfs_ioend_t		**ioendp,
862	struct writeback_control *wbc,
863	int			startio,
864	int			all_bh,
865	pgoff_t			tlast)
866{
867	struct pagevec		pvec;
868	int			done = 0, i;
869
870	pagevec_init(&pvec, 0);
871	while (!done && tindex <= tlast) {
872		unsigned len = min_t(pgoff_t, PAGEVEC_SIZE, tlast - tindex + 1);
873
874		if (!pagevec_lookup(&pvec, inode->i_mapping, tindex, len))
875			break;
876
877		for (i = 0; i < pagevec_count(&pvec); i++) {
878			done = xfs_convert_page(inode, pvec.pages[i], tindex++,
879					iomapp, ioendp, wbc, startio, all_bh);
880			if (done)
881				break;
882		}
883
884		pagevec_release(&pvec);
885		cond_resched();
886	}
887}
888
889/*
890 * Calling this without startio set means we are being asked to make a dirty
891 * page ready for freeing it's buffers.  When called with startio set then
892 * we are coming from writepage.
893 *
894 * When called with startio set it is important that we write the WHOLE
895 * page if possible.
896 * The bh->b_state's cannot know if any of the blocks or which block for
897 * that matter are dirty due to mmap writes, and therefore bh uptodate is
898 * only valid if the page itself isn't completely uptodate.  Some layers
899 * may clear the page dirty flag prior to calling write page, under the
900 * assumption the entire page will be written out; by not writing out the
901 * whole page the page can be reused before all valid dirty data is
902 * written out.  Note: in the case of a page that has been dirty'd by
903 * mapwrite and but partially setup by block_prepare_write the
904 * bh->b_states's will not agree and only ones setup by BPW/BCW will have
905 * valid state, thus the whole page must be written out thing.
906 */
907
908STATIC int
909xfs_page_state_convert(
910	struct inode	*inode,
911	struct page	*page,
912	struct writeback_control *wbc,
913	int		startio,
914	int		unmapped) /* also implies page uptodate */
915{
916	struct buffer_head	*bh, *head;
917	xfs_iomap_t		iomap;
918	xfs_ioend_t		*ioend = NULL, *iohead = NULL;
919	loff_t			offset;
920	unsigned long           p_offset = 0;
921	unsigned int		type;
922	__uint64_t              end_offset;
923	pgoff_t                 end_index, last_index, tlast;
924	ssize_t			size, len;
925	int			flags, err, iomap_valid = 0, uptodate = 1;
926	int			page_dirty, count = 0;
927	int			trylock = 0;
928	int			all_bh = unmapped;
929
930	if (startio) {
931		if (wbc->sync_mode == WB_SYNC_NONE && wbc->nonblocking)
932			trylock |= BMAPI_TRYLOCK;
933	}
934
935	/* Is this page beyond the end of the file? */
936	offset = i_size_read(inode);
937	end_index = offset >> PAGE_CACHE_SHIFT;
938	last_index = (offset - 1) >> PAGE_CACHE_SHIFT;
939	if (page->index >= end_index) {
940		if ((page->index >= end_index + 1) ||
941		    !(i_size_read(inode) & (PAGE_CACHE_SIZE - 1))) {
942			if (startio)
943				unlock_page(page);
944			return 0;
945		}
946	}
947
948	/*
949	 * page_dirty is initially a count of buffers on the page before
950	 * EOF and is decremented as we move each into a cleanable state.
951	 *
952	 * Derivation:
953	 *
954	 * End offset is the highest offset that this page should represent.
955	 * If we are on the last page, (end_offset & (PAGE_CACHE_SIZE - 1))
956	 * will evaluate non-zero and be less than PAGE_CACHE_SIZE and
957	 * hence give us the correct page_dirty count. On any other page,
958	 * it will be zero and in that case we need page_dirty to be the
959	 * count of buffers on the page.
960 	 */
961	end_offset = min_t(unsigned long long,
962			(xfs_off_t)(page->index + 1) << PAGE_CACHE_SHIFT, offset);
963	len = 1 << inode->i_blkbits;
964	p_offset = min_t(unsigned long, end_offset & (PAGE_CACHE_SIZE - 1),
965					PAGE_CACHE_SIZE);
966	p_offset = p_offset ? roundup(p_offset, len) : PAGE_CACHE_SIZE;
967	page_dirty = p_offset / len;
968
969	bh = head = page_buffers(page);
970	offset = page_offset(page);
971	flags = BMAPI_READ;
972	type = IOMAP_NEW;
973
974	/* TODO: cleanup count and page_dirty */
975
976	do {
977		if (offset >= end_offset)
978			break;
979		if (!buffer_uptodate(bh))
980			uptodate = 0;
981		if (!(PageUptodate(page) || buffer_uptodate(bh)) && !startio) {
982			/*
983			 * the iomap is actually still valid, but the ioend
984			 * isn't.  shouldn't happen too often.
985			 */
986			iomap_valid = 0;
987			continue;
988		}
989
990		if (iomap_valid)
991			iomap_valid = xfs_iomap_valid(&iomap, offset);
992
993		/*
994		 * First case, map an unwritten extent and prepare for
995		 * extent state conversion transaction on completion.
996		 *
997		 * Second case, allocate space for a delalloc buffer.
998		 * We can return EAGAIN here in the release page case.
999		 *
1000		 * Third case, an unmapped buffer was found, and we are
1001		 * in a path where we need to write the whole page out.
1002		 */
1003		if (buffer_unwritten(bh) || buffer_delay(bh) ||
1004		    ((buffer_uptodate(bh) || PageUptodate(page)) &&
1005		     !buffer_mapped(bh) && (unmapped || startio))) {
1006			/*
1007			 * Make sure we don't use a read-only iomap
1008			 */
1009			if (flags == BMAPI_READ)
1010				iomap_valid = 0;
1011
1012			if (buffer_unwritten(bh)) {
1013				type = IOMAP_UNWRITTEN;
1014				flags = BMAPI_WRITE | BMAPI_IGNSTATE;
1015			} else if (buffer_delay(bh)) {
1016				type = IOMAP_DELAY;
1017				flags = BMAPI_ALLOCATE | trylock;
1018			} else {
1019				type = IOMAP_NEW;
1020				flags = BMAPI_WRITE | BMAPI_MMAP;
1021			}
1022
1023			if (!iomap_valid) {
1024				if (type == IOMAP_NEW) {
1025					size = xfs_probe_cluster(inode,
1026							page, bh, head, 0);
1027				} else {
1028					size = len;
1029				}
1030
1031				err = xfs_map_blocks(inode, offset, size,
1032						&iomap, flags);
1033				if (err)
1034					goto error;
1035				iomap_valid = xfs_iomap_valid(&iomap, offset);
1036			}
1037			if (iomap_valid) {
1038				xfs_map_at_offset(bh, offset,
1039						inode->i_blkbits, &iomap);
1040				if (startio) {
1041					xfs_add_to_ioend(inode, bh, offset,
1042							type, &ioend,
1043							!iomap_valid);
1044				} else {
1045					set_buffer_dirty(bh);
1046					unlock_buffer(bh);
1047					mark_buffer_dirty(bh);
1048				}
1049				page_dirty--;
1050				count++;
1051			}
1052		} else if (buffer_uptodate(bh) && startio) {
1053			/*
1054			 * we got here because the buffer is already mapped.
1055			 * That means it must already have extents allocated
1056			 * underneath it. Map the extent by reading it.
1057			 */
1058			if (!iomap_valid || flags != BMAPI_READ) {
1059				flags = BMAPI_READ;
1060				size = xfs_probe_cluster(inode, page, bh,
1061								head, 1);
1062				err = xfs_map_blocks(inode, offset, size,
1063						&iomap, flags);
1064				if (err)
1065					goto error;
1066				iomap_valid = xfs_iomap_valid(&iomap, offset);
1067			}
1068
1069			/*
1070			 * We set the type to IOMAP_NEW in case we are doing a
1071			 * small write at EOF that is extending the file but
1072			 * without needing an allocation. We need to update the
1073			 * file size on I/O completion in this case so it is
1074			 * the same case as having just allocated a new extent
1075			 * that we are writing into for the first time.
1076			 */
1077			type = IOMAP_NEW;
1078			if (!test_and_set_bit(BH_Lock, &bh->b_state)) {
1079				ASSERT(buffer_mapped(bh));
1080				if (iomap_valid)
1081					all_bh = 1;
1082				xfs_add_to_ioend(inode, bh, offset, type,
1083						&ioend, !iomap_valid);
1084				page_dirty--;
1085				count++;
1086			} else {
1087				iomap_valid = 0;
1088			}
1089		} else if ((buffer_uptodate(bh) || PageUptodate(page)) &&
1090			   (unmapped || startio)) {
1091			iomap_valid = 0;
1092		}
1093
1094		if (!iohead)
1095			iohead = ioend;
1096
1097	} while (offset += len, ((bh = bh->b_this_page) != head));
1098
1099	if (uptodate && bh == head)
1100		SetPageUptodate(page);
1101
1102	if (startio)
1103		xfs_start_page_writeback(page, wbc, 1, count);
1104
1105	if (ioend && iomap_valid) {
1106		offset = (iomap.iomap_offset + iomap.iomap_bsize - 1) >>
1107					PAGE_CACHE_SHIFT;
1108		tlast = min_t(pgoff_t, offset, last_index);
1109		xfs_cluster_write(inode, page->index + 1, &iomap, &ioend,
1110					wbc, startio, all_bh, tlast);
1111	}
1112
1113	if (iohead)
1114		xfs_submit_ioend(iohead);
1115
1116	return page_dirty;
1117
1118error:
1119	if (iohead)
1120		xfs_cancel_ioend(iohead);
1121
1122	/*
1123	 * If it's delalloc and we have nowhere to put it,
1124	 * throw it away, unless the lower layers told
1125	 * us to try again.
1126	 */
1127	if (err != -EAGAIN) {
1128		if (!unmapped)
1129			block_invalidatepage(page, 0);
1130		ClearPageUptodate(page);
1131	}
1132	return err;
1133}
1134
1135/*
1136 * writepage: Called from one of two places:
1137 *
1138 * 1. we are flushing a delalloc buffer head.
1139 *
1140 * 2. we are writing out a dirty page. Typically the page dirty
1141 *    state is cleared before we get here. In this case is it
1142 *    conceivable we have no buffer heads.
1143 *
1144 * For delalloc space on the page we need to allocate space and
1145 * flush it. For unmapped buffer heads on the page we should
1146 * allocate space if the page is uptodate. For any other dirty
1147 * buffer heads on the page we should flush them.
1148 *
1149 * If we detect that a transaction would be required to flush
1150 * the page, we have to check the process flags first, if we
1151 * are already in a transaction or disk I/O during allocations
1152 * is off, we need to fail the writepage and redirty the page.
1153 */
1154
1155STATIC int
1156xfs_vm_writepage(
1157	struct page		*page,
1158	struct writeback_control *wbc)
1159{
1160	int			error;
1161	int			need_trans;
1162	int			delalloc, unmapped, unwritten;
1163	struct inode		*inode = page->mapping->host;
1164
1165	xfs_page_trace(XFS_WRITEPAGE_ENTER, inode, page, 0);
1166
1167	/*
1168	 * We need a transaction if:
1169	 *  1. There are delalloc buffers on the page
1170	 *  2. The page is uptodate and we have unmapped buffers
1171	 *  3. The page is uptodate and we have no buffers
1172	 *  4. There are unwritten buffers on the page
1173	 */
1174
1175	if (!page_has_buffers(page)) {
1176		unmapped = 1;
1177		need_trans = 1;
1178	} else {
1179		xfs_count_page_state(page, &delalloc, &unmapped, &unwritten);
1180		if (!PageUptodate(page))
1181			unmapped = 0;
1182		need_trans = delalloc + unmapped + unwritten;
1183	}
1184
1185	/*
1186	 * If we need a transaction and the process flags say
1187	 * we are already in a transaction, or no IO is allowed
1188	 * then mark the page dirty again and leave the page
1189	 * as is.
1190	 */
1191	if (current_test_flags(PF_FSTRANS) && need_trans)
1192		goto out_fail;
1193
1194	/*
1195	 * Delay hooking up buffer heads until we have
1196	 * made our go/no-go decision.
1197	 */
1198	if (!page_has_buffers(page))
1199		create_empty_buffers(page, 1 << inode->i_blkbits, 0);
1200
1201	/*
1202	 * Convert delayed allocate, unwritten or unmapped space
1203	 * to real space and flush out to disk.
1204	 */
1205	error = xfs_page_state_convert(inode, page, wbc, 1, unmapped);
1206	if (error == -EAGAIN)
1207		goto out_fail;
1208	if (unlikely(error < 0))
1209		goto out_unlock;
1210
1211	return 0;
1212
1213out_fail:
1214	redirty_page_for_writepage(wbc, page);
1215	unlock_page(page);
1216	return 0;
1217out_unlock:
1218	unlock_page(page);
1219	return error;
1220}
1221
1222STATIC int
1223xfs_vm_writepages(
1224	struct address_space	*mapping,
1225	struct writeback_control *wbc)
1226{
1227	struct bhv_vnode	*vp = vn_from_inode(mapping->host);
1228
1229	if (VN_TRUNC(vp))
1230		VUNTRUNCATE(vp);
1231	return generic_writepages(mapping, wbc);
1232}
1233
1234/*
1235 * Called to move a page into cleanable state - and from there
1236 * to be released. Possibly the page is already clean. We always
1237 * have buffer heads in this call.
1238 *
1239 * Returns 0 if the page is ok to release, 1 otherwise.
1240 *
1241 * Possible scenarios are:
1242 *
1243 * 1. We are being called to release a page which has been written
1244 *    to via regular I/O. buffer heads will be dirty and possibly
1245 *    delalloc. If no delalloc buffer heads in this case then we
1246 *    can just return zero.
1247 *
1248 * 2. We are called to release a page which has been written via
1249 *    mmap, all we need to do is ensure there is no delalloc
1250 *    state in the buffer heads, if not we can let the caller
1251 *    free them and we should come back later via writepage.
1252 */
1253STATIC int
1254xfs_vm_releasepage(
1255	struct page		*page,
1256	gfp_t			gfp_mask)
1257{
1258	struct inode		*inode = page->mapping->host;
1259	int			dirty, delalloc, unmapped, unwritten;
1260	struct writeback_control wbc = {
1261		.sync_mode = WB_SYNC_ALL,
1262		.nr_to_write = 1,
1263	};
1264
1265	xfs_page_trace(XFS_RELEASEPAGE_ENTER, inode, page, 0);
1266
1267	if (!page_has_buffers(page))
1268		return 0;
1269
1270	xfs_count_page_state(page, &delalloc, &unmapped, &unwritten);
1271	if (!delalloc && !unwritten)
1272		goto free_buffers;
1273
1274	if (!(gfp_mask & __GFP_FS))
1275		return 0;
1276
1277	/* If we are already inside a transaction or the thread cannot
1278	 * do I/O, we cannot release this page.
1279	 */
1280	if (current_test_flags(PF_FSTRANS))
1281		return 0;
1282
1283	/*
1284	 * Convert delalloc space to real space, do not flush the
1285	 * data out to disk, that will be done by the caller.
1286	 * Never need to allocate space here - we will always
1287	 * come back to writepage in that case.
1288	 */
1289	dirty = xfs_page_state_convert(inode, page, &wbc, 0, 0);
1290	if (dirty == 0 && !unwritten)
1291		goto free_buffers;
1292	return 0;
1293
1294free_buffers:
1295	return try_to_free_buffers(page);
1296}
1297
1298STATIC int
1299__xfs_get_blocks(
1300	struct inode		*inode,
1301	sector_t		iblock,
1302	struct buffer_head	*bh_result,
1303	int			create,
1304	int			direct,
1305	bmapi_flags_t		flags)
1306{
1307	bhv_vnode_t		*vp = vn_from_inode(inode);
1308	xfs_iomap_t		iomap;
1309	xfs_off_t		offset;
1310	ssize_t			size;
1311	int			niomap = 1;
1312	int			error;
1313
1314	offset = (xfs_off_t)iblock << inode->i_blkbits;
1315	ASSERT(bh_result->b_size >= (1 << inode->i_blkbits));
1316	size = bh_result->b_size;
1317	error = bhv_vop_bmap(vp, offset, size,
1318			     create ? flags : BMAPI_READ, &iomap, &niomap);
1319	if (error)
1320		return -error;
1321	if (niomap == 0)
1322		return 0;
1323
1324	if (iomap.iomap_bn != IOMAP_DADDR_NULL) {
1325		/*
1326		 * For unwritten extents do not report a disk address on
1327		 * the read case (treat as if we're reading into a hole).
1328		 */
1329		if (create || !(iomap.iomap_flags & IOMAP_UNWRITTEN)) {
1330			xfs_map_buffer(bh_result, &iomap, offset,
1331				       inode->i_blkbits);
1332		}
1333		if (create && (iomap.iomap_flags & IOMAP_UNWRITTEN)) {
1334			if (direct)
1335				bh_result->b_private = inode;
1336			set_buffer_unwritten(bh_result);
1337		}
1338	}
1339
1340	/*
1341	 * If this is a realtime file, data may be on a different device.
1342	 * to that pointed to from the buffer_head b_bdev currently.
1343	 */
1344	bh_result->b_bdev = iomap.iomap_target->bt_bdev;
1345
1346	/*
1347	 * If we previously allocated a block out beyond eof and we are now
1348	 * coming back to use it then we will need to flag it as new even if it
1349	 * has a disk address.
1350	 *
1351	 * With sub-block writes into unwritten extents we also need to mark
1352	 * the buffer as new so that the unwritten parts of the buffer gets
1353	 * correctly zeroed.
1354	 */
1355	if (create &&
1356	    ((!buffer_mapped(bh_result) && !buffer_uptodate(bh_result)) ||
1357	     (offset >= i_size_read(inode)) ||
1358	     (iomap.iomap_flags & (IOMAP_NEW|IOMAP_UNWRITTEN))))
1359		set_buffer_new(bh_result);
1360
1361	if (iomap.iomap_flags & IOMAP_DELAY) {
1362		BUG_ON(direct);
1363		if (create) {
1364			set_buffer_uptodate(bh_result);
1365			set_buffer_mapped(bh_result);
1366			set_buffer_delay(bh_result);
1367		}
1368	}
1369
1370	if (direct || size > (1 << inode->i_blkbits)) {
1371		ASSERT(iomap.iomap_bsize - iomap.iomap_delta > 0);
1372		offset = min_t(xfs_off_t,
1373				iomap.iomap_bsize - iomap.iomap_delta, size);
1374		bh_result->b_size = (ssize_t)min_t(xfs_off_t, LONG_MAX, offset);
1375	}
1376
1377	return 0;
1378}
1379
1380int
1381xfs_get_blocks(
1382	struct inode		*inode,
1383	sector_t		iblock,
1384	struct buffer_head	*bh_result,
1385	int			create)
1386{
1387	return __xfs_get_blocks(inode, iblock,
1388				bh_result, create, 0, BMAPI_WRITE);
1389}
1390
1391STATIC int
1392xfs_get_blocks_direct(
1393	struct inode		*inode,
1394	sector_t		iblock,
1395	struct buffer_head	*bh_result,
1396	int			create)
1397{
1398	return __xfs_get_blocks(inode, iblock,
1399				bh_result, create, 1, BMAPI_WRITE|BMAPI_DIRECT);
1400}
1401
1402STATIC void
1403xfs_end_io_direct(
1404	struct kiocb	*iocb,
1405	loff_t		offset,
1406	ssize_t		size,
1407	void		*private)
1408{
1409	xfs_ioend_t	*ioend = iocb->private;
1410
1411	/*
1412	 * Non-NULL private data means we need to issue a transaction to
1413	 * convert a range from unwritten to written extents.  This needs
1414	 * to happen from process context but aio+dio I/O completion
1415	 * happens from irq context so we need to defer it to a workqueue.
1416	 * This is not necessary for synchronous direct I/O, but we do
1417	 * it anyway to keep the code uniform and simpler.
1418	 *
1419	 * The core direct I/O code might be changed to always call the
1420	 * completion handler in the future, in which case all this can
1421	 * go away.
1422	 */
1423	ioend->io_offset = offset;
1424	ioend->io_size = size;
1425	if (ioend->io_type == IOMAP_READ) {
1426		xfs_finish_ioend(ioend);
1427	} else if (private && size > 0) {
1428		xfs_finish_ioend(ioend);
1429	} else {
1430		/*
1431		 * A direct I/O write ioend starts it's life in unwritten
1432		 * state in case they map an unwritten extent.  This write
1433		 * didn't map an unwritten extent so switch it's completion
1434		 * handler.
1435		 */
1436		INIT_WORK(&ioend->io_work, xfs_end_bio_written);
1437		xfs_finish_ioend(ioend);
1438	}
1439
1440	/*
1441	 * blockdev_direct_IO can return an error even after the I/O
1442	 * completion handler was called.  Thus we need to protect
1443	 * against double-freeing.
1444	 */
1445	iocb->private = NULL;
1446}
1447
1448STATIC ssize_t
1449xfs_vm_direct_IO(
1450	int			rw,
1451	struct kiocb		*iocb,
1452	const struct iovec	*iov,
1453	loff_t			offset,
1454	unsigned long		nr_segs)
1455{
1456	struct file	*file = iocb->ki_filp;
1457	struct inode	*inode = file->f_mapping->host;
1458	bhv_vnode_t	*vp = vn_from_inode(inode);
1459	xfs_iomap_t	iomap;
1460	int		maps = 1;
1461	int		error;
1462	ssize_t		ret;
1463
1464	error = bhv_vop_bmap(vp, offset, 0, BMAPI_DEVICE, &iomap, &maps);
1465	if (error)
1466		return -error;
1467
1468	if (rw == WRITE) {
1469		iocb->private = xfs_alloc_ioend(inode, IOMAP_UNWRITTEN);
1470		ret = blockdev_direct_IO_own_locking(rw, iocb, inode,
1471			iomap.iomap_target->bt_bdev,
1472			iov, offset, nr_segs,
1473			xfs_get_blocks_direct,
1474			xfs_end_io_direct);
1475	} else {
1476		iocb->private = xfs_alloc_ioend(inode, IOMAP_READ);
1477		ret = blockdev_direct_IO_no_locking(rw, iocb, inode,
1478			iomap.iomap_target->bt_bdev,
1479			iov, offset, nr_segs,
1480			xfs_get_blocks_direct,
1481			xfs_end_io_direct);
1482	}
1483
1484	if (unlikely(ret != -EIOCBQUEUED && iocb->private))
1485		xfs_destroy_ioend(iocb->private);
1486	return ret;
1487}
1488
1489STATIC int
1490xfs_vm_prepare_write(
1491	struct file		*file,
1492	struct page		*page,
1493	unsigned int		from,
1494	unsigned int		to)
1495{
1496	return block_prepare_write(page, from, to, xfs_get_blocks);
1497}
1498
1499STATIC sector_t
1500xfs_vm_bmap(
1501	struct address_space	*mapping,
1502	sector_t		block)
1503{
1504	struct inode		*inode = (struct inode *)mapping->host;
1505	bhv_vnode_t		*vp = vn_from_inode(inode);
1506
1507	vn_trace_entry(vp, __FUNCTION__, (inst_t *)__return_address);
1508	bhv_vop_rwlock(vp, VRWLOCK_READ);
1509	bhv_vop_flush_pages(vp, (xfs_off_t)0, -1, 0, FI_REMAPF);
1510	bhv_vop_rwunlock(vp, VRWLOCK_READ);
1511	return generic_block_bmap(mapping, block, xfs_get_blocks);
1512}
1513
1514STATIC int
1515xfs_vm_readpage(
1516	struct file		*unused,
1517	struct page		*page)
1518{
1519	return mpage_readpage(page, xfs_get_blocks);
1520}
1521
1522STATIC int
1523xfs_vm_readpages(
1524	struct file		*unused,
1525	struct address_space	*mapping,
1526	struct list_head	*pages,
1527	unsigned		nr_pages)
1528{
1529	return mpage_readpages(mapping, pages, nr_pages, xfs_get_blocks);
1530}
1531
1532STATIC void
1533xfs_vm_invalidatepage(
1534	struct page		*page,
1535	unsigned long		offset)
1536{
1537	xfs_page_trace(XFS_INVALIDPAGE_ENTER,
1538			page->mapping->host, page, offset);
1539	block_invalidatepage(page, offset);
1540}
1541
1542const struct address_space_operations xfs_address_space_operations = {
1543	.readpage		= xfs_vm_readpage,
1544	.readpages		= xfs_vm_readpages,
1545	.writepage		= xfs_vm_writepage,
1546	.writepages		= xfs_vm_writepages,
1547	.sync_page		= block_sync_page,
1548	.releasepage		= xfs_vm_releasepage,
1549	.invalidatepage		= xfs_vm_invalidatepage,
1550	.prepare_write		= xfs_vm_prepare_write,
1551	.commit_write		= generic_commit_write,
1552	.bmap			= xfs_vm_bmap,
1553	.direct_IO		= xfs_vm_direct_IO,
1554	.migratepage		= buffer_migrate_page,
1555};
1556