7aa398724706a9d1d8d6e2dada0fd7126acae9d4
[linux-2.6.git] / fs / xfs / linux-2.6 / xfs_aops.c
1 /*
2  * Copyright (c) 2000-2005 Silicon Graphics, Inc.  All Rights Reserved.
3  *
4  * This program is free software; you can redistribute it and/or modify it
5  * under the terms of version 2 of the GNU General Public License as
6  * published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it would be useful, but
9  * WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
11  *
12  * Further, this software is distributed without any warranty that it is
13  * free of the rightful claim of any third person regarding infringement
14  * or the like.  Any license provided herein, whether implied or
15  * otherwise, applies only to this software file.  Patent licenses, if
16  * any, provided herein do not apply to combinations of this program with
17  * other software, or any other product whatsoever.
18  *
19  * You should have received a copy of the GNU General Public License along
20  * with this program; if not, write the Free Software Foundation, Inc., 59
21  * Temple Place - Suite 330, Boston MA 02111-1307, USA.
22  *
23  * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
24  * Mountain View, CA  94043, or:
25  *
26  * http://www.sgi.com
27  *
28  * For further information regarding this notice, see:
29  *
30  * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/
31  */
32
33 #include "xfs.h"
34 #include "xfs_inum.h"
35 #include "xfs_log.h"
36 #include "xfs_sb.h"
37 #include "xfs_dir.h"
38 #include "xfs_dir2.h"
39 #include "xfs_trans.h"
40 #include "xfs_dmapi.h"
41 #include "xfs_mount.h"
42 #include "xfs_bmap_btree.h"
43 #include "xfs_alloc_btree.h"
44 #include "xfs_ialloc_btree.h"
45 #include "xfs_alloc.h"
46 #include "xfs_btree.h"
47 #include "xfs_attr_sf.h"
48 #include "xfs_dir_sf.h"
49 #include "xfs_dir2_sf.h"
50 #include "xfs_dinode.h"
51 #include "xfs_inode.h"
52 #include "xfs_error.h"
53 #include "xfs_rw.h"
54 #include "xfs_iomap.h"
55 #include <linux/mpage.h>
56 #include <linux/writeback.h>
57
58 STATIC void xfs_count_page_state(struct page *, int *, int *, int *);
59 STATIC void xfs_convert_page(struct inode *, struct page *, xfs_iomap_t *,
60                 struct writeback_control *wbc, void *, int, int);
61
62 #if defined(XFS_RW_TRACE)
63 void
64 xfs_page_trace(
65         int             tag,
66         struct inode    *inode,
67         struct page     *page,
68         int             mask)
69 {
70         xfs_inode_t     *ip;
71         bhv_desc_t      *bdp;
72         vnode_t         *vp = LINVFS_GET_VP(inode);
73         loff_t          isize = i_size_read(inode);
74         loff_t          offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
75         int             delalloc = -1, unmapped = -1, unwritten = -1;
76
77         if (page_has_buffers(page))
78                 xfs_count_page_state(page, &delalloc, &unmapped, &unwritten);
79
80         bdp = vn_bhv_lookup(VN_BHV_HEAD(vp), &xfs_vnodeops);
81         ip = XFS_BHVTOI(bdp);
82         if (!ip->i_rwtrace)
83                 return;
84
85         ktrace_enter(ip->i_rwtrace,
86                 (void *)((unsigned long)tag),
87                 (void *)ip,
88                 (void *)inode,
89                 (void *)page,
90                 (void *)((unsigned long)mask),
91                 (void *)((unsigned long)((ip->i_d.di_size >> 32) & 0xffffffff)),
92                 (void *)((unsigned long)(ip->i_d.di_size & 0xffffffff)),
93                 (void *)((unsigned long)((isize >> 32) & 0xffffffff)),
94                 (void *)((unsigned long)(isize & 0xffffffff)),
95                 (void *)((unsigned long)((offset >> 32) & 0xffffffff)),
96                 (void *)((unsigned long)(offset & 0xffffffff)),
97                 (void *)((unsigned long)delalloc),
98                 (void *)((unsigned long)unmapped),
99                 (void *)((unsigned long)unwritten),
100                 (void *)NULL,
101                 (void *)NULL);
102 }
103 #else
104 #define xfs_page_trace(tag, inode, page, mask)
105 #endif
106
107 /*
108  * Schedule IO completion handling on a xfsdatad if this was
109  * the final hold on this ioend.
110  */
111 STATIC void
112 xfs_finish_ioend(
113         xfs_ioend_t             *ioend)
114 {
115         if (atomic_dec_and_test(&ioend->io_remaining))
116                 queue_work(xfsdatad_workqueue, &ioend->io_work);
117 }
118
119 STATIC void
120 xfs_destroy_ioend(
121         xfs_ioend_t             *ioend)
122 {
123         vn_iowake(ioend->io_vnode);
124         mempool_free(ioend, xfs_ioend_pool);
125 }
126
127 /*
128  * Issue transactions to convert a buffer range from unwritten
129  * to written extents.
130  */
131 STATIC void
132 xfs_end_bio_unwritten(
133         void                    *data)
134 {
135         xfs_ioend_t             *ioend = data;
136         vnode_t                 *vp = ioend->io_vnode;
137         xfs_off_t               offset = ioend->io_offset;
138         size_t                  size = ioend->io_size;
139         struct buffer_head      *bh, *next;
140         int                     error;
141
142         if (ioend->io_uptodate)
143                 VOP_BMAP(vp, offset, size, BMAPI_UNWRITTEN, NULL, NULL, error);
144
145         /* ioend->io_buffer_head is only non-NULL for buffered I/O */
146         for (bh = ioend->io_buffer_head; bh; bh = next) {
147                 next = bh->b_private;
148
149                 bh->b_end_io = NULL;
150                 clear_buffer_unwritten(bh);
151                 end_buffer_async_write(bh, ioend->io_uptodate);
152         }
153
154         xfs_destroy_ioend(ioend);
155 }
156
157 /*
158  * Allocate and initialise an IO completion structure.
159  * We need to track unwritten extent write completion here initially.
160  * We'll need to extend this for updating the ondisk inode size later
161  * (vs. incore size).
162  */
163 STATIC xfs_ioend_t *
164 xfs_alloc_ioend(
165         struct inode            *inode)
166 {
167         xfs_ioend_t             *ioend;
168
169         ioend = mempool_alloc(xfs_ioend_pool, GFP_NOFS);
170
171         /*
172          * Set the count to 1 initially, which will prevent an I/O
173          * completion callback from happening before we have started
174          * all the I/O from calling the completion routine too early.
175          */
176         atomic_set(&ioend->io_remaining, 1);
177         ioend->io_uptodate = 1; /* cleared if any I/O fails */
178         ioend->io_vnode = LINVFS_GET_VP(inode);
179         ioend->io_buffer_head = NULL;
180         atomic_inc(&ioend->io_vnode->v_iocount);
181         ioend->io_offset = 0;
182         ioend->io_size = 0;
183
184         INIT_WORK(&ioend->io_work, xfs_end_bio_unwritten, ioend);
185
186         return ioend;
187 }
188
189 void
190 linvfs_unwritten_done(
191         struct buffer_head      *bh,
192         int                     uptodate)
193 {
194         xfs_ioend_t             *ioend = bh->b_private;
195         static spinlock_t       unwritten_done_lock = SPIN_LOCK_UNLOCKED;
196         unsigned long           flags;
197
198         ASSERT(buffer_unwritten(bh));
199         bh->b_end_io = NULL;
200
201         if (!uptodate)
202                 ioend->io_uptodate = 0;
203
204         /*
205          * Deep magic here.  We reuse b_private in the buffer_heads to build
206          * a chain for completing the I/O from user context after we've issued
207          * a transaction to convert the unwritten extent.
208          */
209         spin_lock_irqsave(&unwritten_done_lock, flags);
210         bh->b_private = ioend->io_buffer_head;
211         ioend->io_buffer_head = bh;
212         spin_unlock_irqrestore(&unwritten_done_lock, flags);
213
214         xfs_finish_ioend(ioend);
215 }
216
217 STATIC int
218 xfs_map_blocks(
219         struct inode            *inode,
220         loff_t                  offset,
221         ssize_t                 count,
222         xfs_iomap_t             *mapp,
223         int                     flags)
224 {
225         vnode_t                 *vp = LINVFS_GET_VP(inode);
226         int                     error, nmaps = 1;
227
228         VOP_BMAP(vp, offset, count, flags, mapp, &nmaps, error);
229         if (!error && (flags & (BMAPI_WRITE|BMAPI_ALLOCATE)))
230                 VMODIFY(vp);
231         return -error;
232 }
233
234 /*
235  * Finds the corresponding mapping in block @map array of the
236  * given @offset within a @page.
237  */
238 STATIC xfs_iomap_t *
239 xfs_offset_to_map(
240         struct page             *page,
241         xfs_iomap_t             *iomapp,
242         unsigned long           offset)
243 {
244         loff_t                  full_offset;    /* offset from start of file */
245
246         ASSERT(offset < PAGE_CACHE_SIZE);
247
248         full_offset = page->index;              /* NB: using 64bit number */
249         full_offset <<= PAGE_CACHE_SHIFT;       /* offset from file start */
250         full_offset += offset;                  /* offset from page start */
251
252         if (full_offset < iomapp->iomap_offset)
253                 return NULL;
254         if (iomapp->iomap_offset + (iomapp->iomap_bsize -1) >= full_offset)
255                 return iomapp;
256         return NULL;
257 }
258
259 STATIC void
260 xfs_map_at_offset(
261         struct page             *page,
262         struct buffer_head      *bh,
263         unsigned long           offset,
264         int                     block_bits,
265         xfs_iomap_t             *iomapp)
266 {
267         xfs_daddr_t             bn;
268         loff_t                  delta;
269         int                     sector_shift;
270
271         ASSERT(!(iomapp->iomap_flags & IOMAP_HOLE));
272         ASSERT(!(iomapp->iomap_flags & IOMAP_DELAY));
273         ASSERT(iomapp->iomap_bn != IOMAP_DADDR_NULL);
274
275         delta = page->index;
276         delta <<= PAGE_CACHE_SHIFT;
277         delta += offset;
278         delta -= iomapp->iomap_offset;
279         delta >>= block_bits;
280
281         sector_shift = block_bits - BBSHIFT;
282         bn = iomapp->iomap_bn >> sector_shift;
283         bn += delta;
284         BUG_ON(!bn && !(iomapp->iomap_flags & IOMAP_REALTIME));
285         ASSERT((bn << sector_shift) >= iomapp->iomap_bn);
286
287         lock_buffer(bh);
288         bh->b_blocknr = bn;
289         bh->b_bdev = iomapp->iomap_target->pbr_bdev;
290         set_buffer_mapped(bh);
291         clear_buffer_delay(bh);
292 }
293
294 /*
295  * Look for a page at index which is unlocked and contains our
296  * unwritten extent flagged buffers at its head.  Returns page
297  * locked and with an extra reference count, and length of the
298  * unwritten extent component on this page that we can write,
299  * in units of filesystem blocks.
300  */
301 STATIC struct page *
302 xfs_probe_unwritten_page(
303         struct address_space    *mapping,
304         pgoff_t                 index,
305         xfs_iomap_t             *iomapp,
306         xfs_ioend_t             *ioend,
307         unsigned long           max_offset,
308         unsigned long           *fsbs,
309         unsigned int            bbits)
310 {
311         struct page             *page;
312
313         page = find_trylock_page(mapping, index);
314         if (!page)
315                 return NULL;
316         if (PageWriteback(page))
317                 goto out;
318
319         if (page->mapping && page_has_buffers(page)) {
320                 struct buffer_head      *bh, *head;
321                 unsigned long           p_offset = 0;
322
323                 *fsbs = 0;
324                 bh = head = page_buffers(page);
325                 do {
326                         if (!buffer_unwritten(bh) || !buffer_uptodate(bh))
327                                 break;
328                         if (!xfs_offset_to_map(page, iomapp, p_offset))
329                                 break;
330                         if (p_offset >= max_offset)
331                                 break;
332                         xfs_map_at_offset(page, bh, p_offset, bbits, iomapp);
333                         set_buffer_unwritten_io(bh);
334                         bh->b_private = ioend;
335                         p_offset += bh->b_size;
336                         (*fsbs)++;
337                 } while ((bh = bh->b_this_page) != head);
338
339                 if (p_offset)
340                         return page;
341         }
342
343 out:
344         unlock_page(page);
345         return NULL;
346 }
347
348 /*
349  * Look for a page at index which is unlocked and not mapped
350  * yet - clustering for mmap write case.
351  */
352 STATIC unsigned int
353 xfs_probe_unmapped_page(
354         struct address_space    *mapping,
355         pgoff_t                 index,
356         unsigned int            pg_offset)
357 {
358         struct page             *page;
359         int                     ret = 0;
360
361         page = find_trylock_page(mapping, index);
362         if (!page)
363                 return 0;
364         if (PageWriteback(page))
365                 goto out;
366
367         if (page->mapping && PageDirty(page)) {
368                 if (page_has_buffers(page)) {
369                         struct buffer_head      *bh, *head;
370
371                         bh = head = page_buffers(page);
372                         do {
373                                 if (buffer_mapped(bh) || !buffer_uptodate(bh))
374                                         break;
375                                 ret += bh->b_size;
376                                 if (ret >= pg_offset)
377                                         break;
378                         } while ((bh = bh->b_this_page) != head);
379                 } else
380                         ret = PAGE_CACHE_SIZE;
381         }
382
383 out:
384         unlock_page(page);
385         return ret;
386 }
387
388 STATIC unsigned int
389 xfs_probe_unmapped_cluster(
390         struct inode            *inode,
391         struct page             *startpage,
392         struct buffer_head      *bh,
393         struct buffer_head      *head)
394 {
395         pgoff_t                 tindex, tlast, tloff;
396         unsigned int            pg_offset, len, total = 0;
397         struct address_space    *mapping = inode->i_mapping;
398
399         /* First sum forwards in this page */
400         do {
401                 if (buffer_mapped(bh))
402                         break;
403                 total += bh->b_size;
404         } while ((bh = bh->b_this_page) != head);
405
406         /* If we reached the end of the page, sum forwards in
407          * following pages.
408          */
409         if (bh == head) {
410                 tlast = i_size_read(inode) >> PAGE_CACHE_SHIFT;
411                 /* Prune this back to avoid pathological behavior */
412                 tloff = min(tlast, startpage->index + 64);
413                 for (tindex = startpage->index + 1; tindex < tloff; tindex++) {
414                         len = xfs_probe_unmapped_page(mapping, tindex,
415                                                         PAGE_CACHE_SIZE);
416                         if (!len)
417                                 return total;
418                         total += len;
419                 }
420                 if (tindex == tlast &&
421                     (pg_offset = i_size_read(inode) & (PAGE_CACHE_SIZE - 1))) {
422                         total += xfs_probe_unmapped_page(mapping,
423                                                         tindex, pg_offset);
424                 }
425         }
426         return total;
427 }
428
429 /*
430  * Probe for a given page (index) in the inode and test if it is delayed
431  * and without unwritten buffers.  Returns page locked and with an extra
432  * reference count.
433  */
434 STATIC struct page *
435 xfs_probe_delalloc_page(
436         struct inode            *inode,
437         pgoff_t                 index)
438 {
439         struct page             *page;
440
441         page = find_trylock_page(inode->i_mapping, index);
442         if (!page)
443                 return NULL;
444         if (PageWriteback(page))
445                 goto out;
446
447         if (page->mapping && page_has_buffers(page)) {
448                 struct buffer_head      *bh, *head;
449                 int                     acceptable = 0;
450
451                 bh = head = page_buffers(page);
452                 do {
453                         if (buffer_unwritten(bh)) {
454                                 acceptable = 0;
455                                 break;
456                         } else if (buffer_delay(bh)) {
457                                 acceptable = 1;
458                         }
459                 } while ((bh = bh->b_this_page) != head);
460
461                 if (acceptable)
462                         return page;
463         }
464
465 out:
466         unlock_page(page);
467         return NULL;
468 }
469
470 STATIC int
471 xfs_map_unwritten(
472         struct inode            *inode,
473         struct page             *start_page,
474         struct buffer_head      *head,
475         struct buffer_head      *curr,
476         unsigned long           p_offset,
477         int                     block_bits,
478         xfs_iomap_t             *iomapp,
479         struct writeback_control *wbc,
480         int                     startio,
481         int                     all_bh)
482 {
483         struct buffer_head      *bh = curr;
484         xfs_iomap_t             *tmp;
485         xfs_ioend_t             *ioend;
486         loff_t                  offset;
487         unsigned long           nblocks = 0;
488
489         offset = start_page->index;
490         offset <<= PAGE_CACHE_SHIFT;
491         offset += p_offset;
492
493         ioend = xfs_alloc_ioend(inode);
494
495         /* First map forwards in the page consecutive buffers
496          * covering this unwritten extent
497          */
498         do {
499                 if (!buffer_unwritten(bh))
500                         break;
501                 tmp = xfs_offset_to_map(start_page, iomapp, p_offset);
502                 if (!tmp)
503                         break;
504                 xfs_map_at_offset(start_page, bh, p_offset, block_bits, iomapp);
505                 set_buffer_unwritten_io(bh);
506                 bh->b_private = ioend;
507                 p_offset += bh->b_size;
508                 nblocks++;
509         } while ((bh = bh->b_this_page) != head);
510
511         atomic_add(nblocks, &ioend->io_remaining);
512
513         /* If we reached the end of the page, map forwards in any
514          * following pages which are also covered by this extent.
515          */
516         if (bh == head) {
517                 struct address_space    *mapping = inode->i_mapping;
518                 pgoff_t                 tindex, tloff, tlast;
519                 unsigned long           bs;
520                 unsigned int            pg_offset, bbits = inode->i_blkbits;
521                 struct page             *page;
522
523                 tlast = i_size_read(inode) >> PAGE_CACHE_SHIFT;
524                 tloff = (iomapp->iomap_offset + iomapp->iomap_bsize) >> PAGE_CACHE_SHIFT;
525                 tloff = min(tlast, tloff);
526                 for (tindex = start_page->index + 1; tindex < tloff; tindex++) {
527                         page = xfs_probe_unwritten_page(mapping,
528                                                 tindex, iomapp, ioend,
529                                                 PAGE_CACHE_SIZE, &bs, bbits);
530                         if (!page)
531                                 break;
532                         nblocks += bs;
533                         atomic_add(bs, &ioend->io_remaining);
534                         xfs_convert_page(inode, page, iomapp, wbc, ioend,
535                                                         startio, all_bh);
536                         /* stop if converting the next page might add
537                          * enough blocks that the corresponding byte
538                          * count won't fit in our ulong page buf length */
539                         if (nblocks >= ((ULONG_MAX - PAGE_SIZE) >> block_bits))
540                                 goto enough;
541                 }
542
543                 if (tindex == tlast &&
544                     (pg_offset = (i_size_read(inode) & (PAGE_CACHE_SIZE - 1)))) {
545                         page = xfs_probe_unwritten_page(mapping,
546                                                         tindex, iomapp, ioend,
547                                                         pg_offset, &bs, bbits);
548                         if (page) {
549                                 nblocks += bs;
550                                 atomic_add(bs, &ioend->io_remaining);
551                                 xfs_convert_page(inode, page, iomapp, wbc, ioend,
552                                                         startio, all_bh);
553                                 if (nblocks >= ((ULONG_MAX - PAGE_SIZE) >> block_bits))
554                                         goto enough;
555                         }
556                 }
557         }
558
559 enough:
560         ioend->io_size = (xfs_off_t)nblocks << block_bits;
561         ioend->io_offset = offset;
562         xfs_finish_ioend(ioend);
563         return 0;
564 }
565
566 STATIC void
567 xfs_submit_page(
568         struct page             *page,
569         struct writeback_control *wbc,
570         struct buffer_head      *bh_arr[],
571         int                     bh_count,
572         int                     probed_page,
573         int                     clear_dirty)
574 {
575         struct buffer_head      *bh;
576         int                     i;
577
578         BUG_ON(PageWriteback(page));
579         if (bh_count)
580                 set_page_writeback(page);
581         if (clear_dirty)
582                 clear_page_dirty(page);
583         unlock_page(page);
584
585         if (bh_count) {
586                 for (i = 0; i < bh_count; i++) {
587                         bh = bh_arr[i];
588                         mark_buffer_async_write(bh);
589                         if (buffer_unwritten(bh))
590                                 set_buffer_unwritten_io(bh);
591                         set_buffer_uptodate(bh);
592                         clear_buffer_dirty(bh);
593                 }
594
595                 for (i = 0; i < bh_count; i++)
596                         submit_bh(WRITE, bh_arr[i]);
597
598                 if (probed_page && clear_dirty)
599                         wbc->nr_to_write--;     /* Wrote an "extra" page */
600         }
601 }
602
603 /*
604  * Allocate & map buffers for page given the extent map. Write it out.
605  * except for the original page of a writepage, this is called on
606  * delalloc/unwritten pages only, for the original page it is possible
607  * that the page has no mapping at all.
608  */
609 STATIC void
610 xfs_convert_page(
611         struct inode            *inode,
612         struct page             *page,
613         xfs_iomap_t             *iomapp,
614         struct writeback_control *wbc,
615         void                    *private,
616         int                     startio,
617         int                     all_bh)
618 {
619         struct buffer_head      *bh_arr[MAX_BUF_PER_PAGE], *bh, *head;
620         xfs_iomap_t             *mp = iomapp, *tmp;
621         unsigned long           offset, end_offset;
622         int                     index = 0;
623         int                     bbits = inode->i_blkbits;
624         int                     len, page_dirty;
625
626         end_offset = (i_size_read(inode) & (PAGE_CACHE_SIZE - 1));
627
628         /*
629          * page_dirty is initially a count of buffers on the page before
630          * EOF and is decrememted as we move each into a cleanable state.
631          */
632         len = 1 << inode->i_blkbits;
633         end_offset = max(end_offset, PAGE_CACHE_SIZE);
634         end_offset = roundup(end_offset, len);
635         page_dirty = end_offset / len;
636
637         offset = 0;
638         bh = head = page_buffers(page);
639         do {
640                 if (offset >= end_offset)
641                         break;
642                 if (!(PageUptodate(page) || buffer_uptodate(bh)))
643                         continue;
644                 if (buffer_mapped(bh) && all_bh &&
645                     !(buffer_unwritten(bh) || buffer_delay(bh))) {
646                         if (startio) {
647                                 lock_buffer(bh);
648                                 bh_arr[index++] = bh;
649                                 page_dirty--;
650                         }
651                         continue;
652                 }
653                 tmp = xfs_offset_to_map(page, mp, offset);
654                 if (!tmp)
655                         continue;
656                 ASSERT(!(tmp->iomap_flags & IOMAP_HOLE));
657                 ASSERT(!(tmp->iomap_flags & IOMAP_DELAY));
658
659                 /* If this is a new unwritten extent buffer (i.e. one
660                  * that we haven't passed in private data for, we must
661                  * now map this buffer too.
662                  */
663                 if (buffer_unwritten(bh) && !bh->b_end_io) {
664                         ASSERT(tmp->iomap_flags & IOMAP_UNWRITTEN);
665                         xfs_map_unwritten(inode, page, head, bh, offset,
666                                         bbits, tmp, wbc, startio, all_bh);
667                 } else if (! (buffer_unwritten(bh) && buffer_locked(bh))) {
668                         xfs_map_at_offset(page, bh, offset, bbits, tmp);
669                         if (buffer_unwritten(bh)) {
670                                 set_buffer_unwritten_io(bh);
671                                 bh->b_private = private;
672                                 ASSERT(private);
673                         }
674                 }
675                 if (startio) {
676                         bh_arr[index++] = bh;
677                 } else {
678                         set_buffer_dirty(bh);
679                         unlock_buffer(bh);
680                         mark_buffer_dirty(bh);
681                 }
682                 page_dirty--;
683         } while (offset += len, (bh = bh->b_this_page) != head);
684
685         if (startio && index) {
686                 xfs_submit_page(page, wbc, bh_arr, index, 1, !page_dirty);
687         } else {
688                 unlock_page(page);
689         }
690 }
691
692 /*
693  * Convert & write out a cluster of pages in the same extent as defined
694  * by mp and following the start page.
695  */
696 STATIC void
697 xfs_cluster_write(
698         struct inode            *inode,
699         pgoff_t                 tindex,
700         xfs_iomap_t             *iomapp,
701         struct writeback_control *wbc,
702         int                     startio,
703         int                     all_bh,
704         pgoff_t                 tlast)
705 {
706         struct page             *page;
707
708         for (; tindex <= tlast; tindex++) {
709                 page = xfs_probe_delalloc_page(inode, tindex);
710                 if (!page)
711                         break;
712                 xfs_convert_page(inode, page, iomapp, wbc, NULL,
713                                 startio, all_bh);
714         }
715 }
716
717 /*
718  * Calling this without startio set means we are being asked to make a dirty
719  * page ready for freeing it's buffers.  When called with startio set then
720  * we are coming from writepage.
721  *
722  * When called with startio set it is important that we write the WHOLE
723  * page if possible.
724  * The bh->b_state's cannot know if any of the blocks or which block for
725  * that matter are dirty due to mmap writes, and therefore bh uptodate is
726  * only vaild if the page itself isn't completely uptodate.  Some layers
727  * may clear the page dirty flag prior to calling write page, under the
728  * assumption the entire page will be written out; by not writing out the
729  * whole page the page can be reused before all valid dirty data is
730  * written out.  Note: in the case of a page that has been dirty'd by
731  * mapwrite and but partially setup by block_prepare_write the
732  * bh->b_states's will not agree and only ones setup by BPW/BCW will have
733  * valid state, thus the whole page must be written out thing.
734  */
735
736 STATIC int
737 xfs_page_state_convert(
738         struct inode    *inode,
739         struct page     *page,
740         struct writeback_control *wbc,
741         int             startio,
742         int             unmapped) /* also implies page uptodate */
743 {
744         struct buffer_head      *bh_arr[MAX_BUF_PER_PAGE], *bh, *head;
745         xfs_iomap_t             *iomp, iomap;
746         loff_t                  offset;
747         unsigned long           p_offset = 0;
748         __uint64_t              end_offset;
749         pgoff_t                 end_index, last_index, tlast;
750         int                     len, err, i, cnt = 0, uptodate = 1;
751         int                     flags;
752         int                     page_dirty;
753
754         /* wait for other IO threads? */
755         flags = (startio && wbc->sync_mode != WB_SYNC_NONE) ? 0 : BMAPI_TRYLOCK;
756
757         /* Is this page beyond the end of the file? */
758         offset = i_size_read(inode);
759         end_index = offset >> PAGE_CACHE_SHIFT;
760         last_index = (offset - 1) >> PAGE_CACHE_SHIFT;
761         if (page->index >= end_index) {
762                 if ((page->index >= end_index + 1) ||
763                     !(i_size_read(inode) & (PAGE_CACHE_SIZE - 1))) {
764                         err = -EIO;
765                         goto error;
766                 }
767         }
768
769         end_offset = min_t(unsigned long long,
770                         (loff_t)(page->index + 1) << PAGE_CACHE_SHIFT, offset);
771         offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
772
773         /*
774          * page_dirty is initially a count of buffers on the page before
775          * EOF and is decrememted as we move each into a cleanable state.
776          */
777         len = 1 << inode->i_blkbits;
778         p_offset = max(p_offset, PAGE_CACHE_SIZE);
779         p_offset = roundup(p_offset, len);
780         page_dirty = p_offset / len;
781
782         iomp = NULL;
783         p_offset = 0;
784         bh = head = page_buffers(page);
785
786         do {
787                 if (offset >= end_offset)
788                         break;
789                 if (!buffer_uptodate(bh))
790                         uptodate = 0;
791                 if (!(PageUptodate(page) || buffer_uptodate(bh)) && !startio)
792                         continue;
793
794                 if (iomp) {
795                         iomp = xfs_offset_to_map(page, &iomap, p_offset);
796                 }
797
798                 /*
799                  * First case, map an unwritten extent and prepare for
800                  * extent state conversion transaction on completion.
801                  */
802                 if (buffer_unwritten(bh)) {
803                         if (!startio)
804                                 continue;
805                         if (!iomp) {
806                                 err = xfs_map_blocks(inode, offset, len, &iomap,
807                                                 BMAPI_WRITE|BMAPI_IGNSTATE);
808                                 if (err) {
809                                         goto error;
810                                 }
811                                 iomp = xfs_offset_to_map(page, &iomap,
812                                                                 p_offset);
813                         }
814                         if (iomp) {
815                                 if (!bh->b_end_io) {
816                                         err = xfs_map_unwritten(inode, page,
817                                                         head, bh, p_offset,
818                                                         inode->i_blkbits, iomp,
819                                                         wbc, startio, unmapped);
820                                         if (err) {
821                                                 goto error;
822                                         }
823                                 } else {
824                                         set_bit(BH_Lock, &bh->b_state);
825                                 }
826                                 BUG_ON(!buffer_locked(bh));
827                                 bh_arr[cnt++] = bh;
828                                 page_dirty--;
829                         }
830                 /*
831                  * Second case, allocate space for a delalloc buffer.
832                  * We can return EAGAIN here in the release page case.
833                  */
834                 } else if (buffer_delay(bh)) {
835                         if (!iomp) {
836                                 err = xfs_map_blocks(inode, offset, len, &iomap,
837                                                 BMAPI_ALLOCATE | flags);
838                                 if (err) {
839                                         goto error;
840                                 }
841                                 iomp = xfs_offset_to_map(page, &iomap,
842                                                                 p_offset);
843                         }
844                         if (iomp) {
845                                 xfs_map_at_offset(page, bh, p_offset,
846                                                 inode->i_blkbits, iomp);
847                                 if (startio) {
848                                         bh_arr[cnt++] = bh;
849                                 } else {
850                                         set_buffer_dirty(bh);
851                                         unlock_buffer(bh);
852                                         mark_buffer_dirty(bh);
853                                 }
854                                 page_dirty--;
855                         }
856                 } else if ((buffer_uptodate(bh) || PageUptodate(page)) &&
857                            (unmapped || startio)) {
858
859                         if (!buffer_mapped(bh)) {
860                                 int     size;
861
862                                 /*
863                                  * Getting here implies an unmapped buffer
864                                  * was found, and we are in a path where we
865                                  * need to write the whole page out.
866                                  */
867                                 if (!iomp) {
868                                         size = xfs_probe_unmapped_cluster(
869                                                         inode, page, bh, head);
870                                         err = xfs_map_blocks(inode, offset,
871                                                         size, &iomap,
872                                                         BMAPI_WRITE|BMAPI_MMAP);
873                                         if (err) {
874                                                 goto error;
875                                         }
876                                         iomp = xfs_offset_to_map(page, &iomap,
877                                                                      p_offset);
878                                 }
879                                 if (iomp) {
880                                         xfs_map_at_offset(page,
881                                                         bh, p_offset,
882                                                         inode->i_blkbits, iomp);
883                                         if (startio) {
884                                                 bh_arr[cnt++] = bh;
885                                         } else {
886                                                 set_buffer_dirty(bh);
887                                                 unlock_buffer(bh);
888                                                 mark_buffer_dirty(bh);
889                                         }
890                                         page_dirty--;
891                                 }
892                         } else if (startio) {
893                                 if (buffer_uptodate(bh) &&
894                                     !test_and_set_bit(BH_Lock, &bh->b_state)) {
895                                         bh_arr[cnt++] = bh;
896                                         page_dirty--;
897                                 }
898                         }
899                 }
900         } while (offset += len, p_offset += len,
901                 ((bh = bh->b_this_page) != head));
902
903         if (uptodate && bh == head)
904                 SetPageUptodate(page);
905
906         if (startio) {
907                 xfs_submit_page(page, wbc, bh_arr, cnt, 0, !page_dirty);
908         }
909
910         if (iomp) {
911                 offset = (iomp->iomap_offset + iomp->iomap_bsize - 1) >>
912                                         PAGE_CACHE_SHIFT;
913                 tlast = min_t(pgoff_t, offset, last_index);
914                 xfs_cluster_write(inode, page->index + 1, iomp, wbc,
915                                         startio, unmapped, tlast);
916         }
917
918         return page_dirty;
919
920 error:
921         for (i = 0; i < cnt; i++) {
922                 unlock_buffer(bh_arr[i]);
923         }
924
925         /*
926          * If it's delalloc and we have nowhere to put it,
927          * throw it away, unless the lower layers told
928          * us to try again.
929          */
930         if (err != -EAGAIN) {
931                 if (!unmapped) {
932                         block_invalidatepage(page, 0);
933                 }
934                 ClearPageUptodate(page);
935         }
936         return err;
937 }
938
939 STATIC int
940 __linvfs_get_block(
941         struct inode            *inode,
942         sector_t                iblock,
943         unsigned long           blocks,
944         struct buffer_head      *bh_result,
945         int                     create,
946         int                     direct,
947         bmapi_flags_t           flags)
948 {
949         vnode_t                 *vp = LINVFS_GET_VP(inode);
950         xfs_iomap_t             iomap;
951         int                     retpbbm = 1;
952         int                     error;
953         ssize_t                 size;
954         loff_t                  offset = (loff_t)iblock << inode->i_blkbits;
955
956         if (blocks)
957                 size = blocks << inode->i_blkbits;
958         else
959                 size = 1 << inode->i_blkbits;
960
961         VOP_BMAP(vp, offset, size,
962                 create ? flags : BMAPI_READ, &iomap, &retpbbm, error);
963         if (error)
964                 return -error;
965
966         if (retpbbm == 0)
967                 return 0;
968
969         if (iomap.iomap_bn != IOMAP_DADDR_NULL) {
970                 xfs_daddr_t             bn;
971                 loff_t                  delta;
972
973                 /* For unwritten extents do not report a disk address on
974                  * the read case (treat as if we're reading into a hole).
975                  */
976                 if (create || !(iomap.iomap_flags & IOMAP_UNWRITTEN)) {
977                         delta = offset - iomap.iomap_offset;
978                         delta >>= inode->i_blkbits;
979
980                         bn = iomap.iomap_bn >> (inode->i_blkbits - BBSHIFT);
981                         bn += delta;
982                         BUG_ON(!bn && !(iomap.iomap_flags & IOMAP_REALTIME));
983                         bh_result->b_blocknr = bn;
984                         set_buffer_mapped(bh_result);
985                 }
986                 if (create && (iomap.iomap_flags & IOMAP_UNWRITTEN)) {
987                         if (direct)
988                                 bh_result->b_private = inode;
989                         set_buffer_unwritten(bh_result);
990                         set_buffer_delay(bh_result);
991                 }
992         }
993
994         /* If this is a realtime file, data might be on a new device */
995         bh_result->b_bdev = iomap.iomap_target->pbr_bdev;
996
997         /* If we previously allocated a block out beyond eof and
998          * we are now coming back to use it then we will need to
999          * flag it as new even if it has a disk address.
1000          */
1001         if (create &&
1002             ((!buffer_mapped(bh_result) && !buffer_uptodate(bh_result)) ||
1003              (offset >= i_size_read(inode)) || (iomap.iomap_flags & IOMAP_NEW))) {
1004                 set_buffer_new(bh_result);
1005         }
1006
1007         if (iomap.iomap_flags & IOMAP_DELAY) {
1008                 BUG_ON(direct);
1009                 if (create) {
1010                         set_buffer_uptodate(bh_result);
1011                         set_buffer_mapped(bh_result);
1012                         set_buffer_delay(bh_result);
1013                 }
1014         }
1015
1016         if (blocks) {
1017                 bh_result->b_size = (ssize_t)min(
1018                         (loff_t)(iomap.iomap_bsize - iomap.iomap_delta),
1019                         (loff_t)(blocks << inode->i_blkbits));
1020         }
1021
1022         return 0;
1023 }
1024
1025 int
1026 linvfs_get_block(
1027         struct inode            *inode,
1028         sector_t                iblock,
1029         struct buffer_head      *bh_result,
1030         int                     create)
1031 {
1032         return __linvfs_get_block(inode, iblock, 0, bh_result,
1033                                         create, 0, BMAPI_WRITE);
1034 }
1035
1036 STATIC int
1037 linvfs_get_blocks_direct(
1038         struct inode            *inode,
1039         sector_t                iblock,
1040         unsigned long           max_blocks,
1041         struct buffer_head      *bh_result,
1042         int                     create)
1043 {
1044         return __linvfs_get_block(inode, iblock, max_blocks, bh_result,
1045                                         create, 1, BMAPI_WRITE|BMAPI_DIRECT);
1046 }
1047
1048 STATIC void
1049 linvfs_end_io_direct(
1050         struct kiocb    *iocb,
1051         loff_t          offset,
1052         ssize_t         size,
1053         void            *private)
1054 {
1055         xfs_ioend_t     *ioend = iocb->private;
1056
1057         /*
1058          * Non-NULL private data means we need to issue a transaction to
1059          * convert a range from unwritten to written extents.  This needs
1060          * to happen from process contect but aio+dio I/O completion
1061          * happens from irq context so we need to defer it to a workqueue.
1062          * This is not nessecary for synchronous direct I/O, but we do
1063          * it anyway to keep the code uniform and simpler.
1064          *
1065          * The core direct I/O code might be changed to always call the
1066          * completion handler in the future, in which case all this can
1067          * go away.
1068          */
1069         if (private && size > 0) {
1070                 ioend->io_offset = offset;
1071                 ioend->io_size = size;
1072                 xfs_finish_ioend(ioend);
1073         } else {
1074                 ASSERT(size >= 0);
1075                 xfs_destroy_ioend(ioend);
1076         }
1077
1078         /*
1079          * blockdev_direct_IO can return an error even afer the I/O
1080          * completion handler was called.  Thus we need to protect
1081          * against double-freeing.
1082          */
1083         iocb->private = NULL;
1084 }
1085
1086 STATIC ssize_t
1087 linvfs_direct_IO(
1088         int                     rw,
1089         struct kiocb            *iocb,
1090         const struct iovec      *iov,
1091         loff_t                  offset,
1092         unsigned long           nr_segs)
1093 {
1094         struct file     *file = iocb->ki_filp;
1095         struct inode    *inode = file->f_mapping->host;
1096         vnode_t         *vp = LINVFS_GET_VP(inode);
1097         xfs_iomap_t     iomap;
1098         int             maps = 1;
1099         int             error;
1100         ssize_t         ret;
1101
1102         VOP_BMAP(vp, offset, 0, BMAPI_DEVICE, &iomap, &maps, error);
1103         if (error)
1104                 return -error;
1105
1106         iocb->private = xfs_alloc_ioend(inode);
1107
1108         ret = blockdev_direct_IO_own_locking(rw, iocb, inode,
1109                 iomap.iomap_target->pbr_bdev,
1110                 iov, offset, nr_segs,
1111                 linvfs_get_blocks_direct,
1112                 linvfs_end_io_direct);
1113
1114         if (unlikely(ret <= 0 && iocb->private))
1115                 xfs_destroy_ioend(iocb->private);
1116         return ret;
1117 }
1118
1119
1120 STATIC sector_t
1121 linvfs_bmap(
1122         struct address_space    *mapping,
1123         sector_t                block)
1124 {
1125         struct inode            *inode = (struct inode *)mapping->host;
1126         vnode_t                 *vp = LINVFS_GET_VP(inode);
1127         int                     error;
1128
1129         vn_trace_entry(vp, "linvfs_bmap", (inst_t *)__return_address);
1130
1131         VOP_RWLOCK(vp, VRWLOCK_READ);
1132         VOP_FLUSH_PAGES(vp, (xfs_off_t)0, -1, 0, FI_REMAPF, error);
1133         VOP_RWUNLOCK(vp, VRWLOCK_READ);
1134         return generic_block_bmap(mapping, block, linvfs_get_block);
1135 }
1136
1137 STATIC int
1138 linvfs_readpage(
1139         struct file             *unused,
1140         struct page             *page)
1141 {
1142         return mpage_readpage(page, linvfs_get_block);
1143 }
1144
1145 STATIC int
1146 linvfs_readpages(
1147         struct file             *unused,
1148         struct address_space    *mapping,
1149         struct list_head        *pages,
1150         unsigned                nr_pages)
1151 {
1152         return mpage_readpages(mapping, pages, nr_pages, linvfs_get_block);
1153 }
1154
1155 STATIC void
1156 xfs_count_page_state(
1157         struct page             *page,
1158         int                     *delalloc,
1159         int                     *unmapped,
1160         int                     *unwritten)
1161 {
1162         struct buffer_head      *bh, *head;
1163
1164         *delalloc = *unmapped = *unwritten = 0;
1165
1166         bh = head = page_buffers(page);
1167         do {
1168                 if (buffer_uptodate(bh) && !buffer_mapped(bh))
1169                         (*unmapped) = 1;
1170                 else if (buffer_unwritten(bh) && !buffer_delay(bh))
1171                         clear_buffer_unwritten(bh);
1172                 else if (buffer_unwritten(bh))
1173                         (*unwritten) = 1;
1174                 else if (buffer_delay(bh))
1175                         (*delalloc) = 1;
1176         } while ((bh = bh->b_this_page) != head);
1177 }
1178
1179
1180 /*
1181  * writepage: Called from one of two places:
1182  *
1183  * 1. we are flushing a delalloc buffer head.
1184  *
1185  * 2. we are writing out a dirty page. Typically the page dirty
1186  *    state is cleared before we get here. In this case is it
1187  *    conceivable we have no buffer heads.
1188  *
1189  * For delalloc space on the page we need to allocate space and
1190  * flush it. For unmapped buffer heads on the page we should
1191  * allocate space if the page is uptodate. For any other dirty
1192  * buffer heads on the page we should flush them.
1193  *
1194  * If we detect that a transaction would be required to flush
1195  * the page, we have to check the process flags first, if we
1196  * are already in a transaction or disk I/O during allocations
1197  * is off, we need to fail the writepage and redirty the page.
1198  */
1199
1200 STATIC int
1201 linvfs_writepage(
1202         struct page             *page,
1203         struct writeback_control *wbc)
1204 {
1205         int                     error;
1206         int                     need_trans;
1207         int                     delalloc, unmapped, unwritten;
1208         struct inode            *inode = page->mapping->host;
1209
1210         xfs_page_trace(XFS_WRITEPAGE_ENTER, inode, page, 0);
1211
1212         /*
1213          * We need a transaction if:
1214          *  1. There are delalloc buffers on the page
1215          *  2. The page is uptodate and we have unmapped buffers
1216          *  3. The page is uptodate and we have no buffers
1217          *  4. There are unwritten buffers on the page
1218          */
1219
1220         if (!page_has_buffers(page)) {
1221                 unmapped = 1;
1222                 need_trans = 1;
1223         } else {
1224                 xfs_count_page_state(page, &delalloc, &unmapped, &unwritten);
1225                 if (!PageUptodate(page))
1226                         unmapped = 0;
1227                 need_trans = delalloc + unmapped + unwritten;
1228         }
1229
1230         /*
1231          * If we need a transaction and the process flags say
1232          * we are already in a transaction, or no IO is allowed
1233          * then mark the page dirty again and leave the page
1234          * as is.
1235          */
1236         if (PFLAGS_TEST_FSTRANS() && need_trans)
1237                 goto out_fail;
1238
1239         /*
1240          * Delay hooking up buffer heads until we have
1241          * made our go/no-go decision.
1242          */
1243         if (!page_has_buffers(page))
1244                 create_empty_buffers(page, 1 << inode->i_blkbits, 0);
1245
1246         /*
1247          * Convert delayed allocate, unwritten or unmapped space
1248          * to real space and flush out to disk.
1249          */
1250         error = xfs_page_state_convert(inode, page, wbc, 1, unmapped);
1251         if (error == -EAGAIN)
1252                 goto out_fail;
1253         if (unlikely(error < 0))
1254                 goto out_unlock;
1255
1256         return 0;
1257
1258 out_fail:
1259         redirty_page_for_writepage(wbc, page);
1260         unlock_page(page);
1261         return 0;
1262 out_unlock:
1263         unlock_page(page);
1264         return error;
1265 }
1266
1267 STATIC int
1268 linvfs_invalidate_page(
1269         struct page             *page,
1270         unsigned long           offset)
1271 {
1272         xfs_page_trace(XFS_INVALIDPAGE_ENTER,
1273                         page->mapping->host, page, offset);
1274         return block_invalidatepage(page, offset);
1275 }
1276
1277 /*
1278  * Called to move a page into cleanable state - and from there
1279  * to be released. Possibly the page is already clean. We always
1280  * have buffer heads in this call.
1281  *
1282  * Returns 0 if the page is ok to release, 1 otherwise.
1283  *
1284  * Possible scenarios are:
1285  *
1286  * 1. We are being called to release a page which has been written
1287  *    to via regular I/O. buffer heads will be dirty and possibly
1288  *    delalloc. If no delalloc buffer heads in this case then we
1289  *    can just return zero.
1290  *
1291  * 2. We are called to release a page which has been written via
1292  *    mmap, all we need to do is ensure there is no delalloc
1293  *    state in the buffer heads, if not we can let the caller
1294  *    free them and we should come back later via writepage.
1295  */
1296 STATIC int
1297 linvfs_release_page(
1298         struct page             *page,
1299         gfp_t                   gfp_mask)
1300 {
1301         struct inode            *inode = page->mapping->host;
1302         int                     dirty, delalloc, unmapped, unwritten;
1303         struct writeback_control wbc = {
1304                 .sync_mode = WB_SYNC_ALL,
1305                 .nr_to_write = 1,
1306         };
1307
1308         xfs_page_trace(XFS_RELEASEPAGE_ENTER, inode, page, gfp_mask);
1309
1310         xfs_count_page_state(page, &delalloc, &unmapped, &unwritten);
1311         if (!delalloc && !unwritten)
1312                 goto free_buffers;
1313
1314         if (!(gfp_mask & __GFP_FS))
1315                 return 0;
1316
1317         /* If we are already inside a transaction or the thread cannot
1318          * do I/O, we cannot release this page.
1319          */
1320         if (PFLAGS_TEST_FSTRANS())
1321                 return 0;
1322
1323         /*
1324          * Convert delalloc space to real space, do not flush the
1325          * data out to disk, that will be done by the caller.
1326          * Never need to allocate space here - we will always
1327          * come back to writepage in that case.
1328          */
1329         dirty = xfs_page_state_convert(inode, page, &wbc, 0, 0);
1330         if (dirty == 0 && !unwritten)
1331                 goto free_buffers;
1332         return 0;
1333
1334 free_buffers:
1335         return try_to_free_buffers(page);
1336 }
1337
1338 STATIC int
1339 linvfs_prepare_write(
1340         struct file             *file,
1341         struct page             *page,
1342         unsigned int            from,
1343         unsigned int            to)
1344 {
1345         return block_prepare_write(page, from, to, linvfs_get_block);
1346 }
1347
1348 struct address_space_operations linvfs_aops = {
1349         .readpage               = linvfs_readpage,
1350         .readpages              = linvfs_readpages,
1351         .writepage              = linvfs_writepage,
1352         .sync_page              = block_sync_page,
1353         .releasepage            = linvfs_release_page,
1354         .invalidatepage         = linvfs_invalidate_page,
1355         .prepare_write          = linvfs_prepare_write,
1356         .commit_write           = generic_commit_write,
1357         .bmap                   = linvfs_bmap,
1358         .direct_IO              = linvfs_direct_IO,
1359 };