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1da177e4 LT |
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 | void | |
108 | linvfs_unwritten_done( | |
109 | struct buffer_head *bh, | |
110 | int uptodate) | |
111 | { | |
112 | xfs_buf_t *pb = (xfs_buf_t *)bh->b_private; | |
113 | ||
114 | ASSERT(buffer_unwritten(bh)); | |
115 | bh->b_end_io = NULL; | |
116 | clear_buffer_unwritten(bh); | |
117 | if (!uptodate) | |
118 | pagebuf_ioerror(pb, EIO); | |
119 | if (atomic_dec_and_test(&pb->pb_io_remaining) == 1) { | |
120 | pagebuf_iodone(pb, 1, 1); | |
121 | } | |
122 | end_buffer_async_write(bh, uptodate); | |
123 | } | |
124 | ||
125 | /* | |
126 | * Issue transactions to convert a buffer range from unwritten | |
127 | * to written extents (buffered IO). | |
128 | */ | |
129 | STATIC void | |
130 | linvfs_unwritten_convert( | |
131 | xfs_buf_t *bp) | |
132 | { | |
133 | vnode_t *vp = XFS_BUF_FSPRIVATE(bp, vnode_t *); | |
134 | int error; | |
135 | ||
136 | BUG_ON(atomic_read(&bp->pb_hold) < 1); | |
137 | VOP_BMAP(vp, XFS_BUF_OFFSET(bp), XFS_BUF_SIZE(bp), | |
138 | BMAPI_UNWRITTEN, NULL, NULL, error); | |
139 | XFS_BUF_SET_FSPRIVATE(bp, NULL); | |
140 | XFS_BUF_CLR_IODONE_FUNC(bp); | |
141 | XFS_BUF_UNDATAIO(bp); | |
142 | iput(LINVFS_GET_IP(vp)); | |
143 | pagebuf_iodone(bp, 0, 0); | |
144 | } | |
145 | ||
146 | /* | |
147 | * Issue transactions to convert a buffer range from unwritten | |
148 | * to written extents (direct IO). | |
149 | */ | |
150 | STATIC void | |
151 | linvfs_unwritten_convert_direct( | |
152 | struct inode *inode, | |
153 | loff_t offset, | |
154 | ssize_t size, | |
155 | void *private) | |
156 | { | |
157 | ASSERT(!private || inode == (struct inode *)private); | |
158 | ||
159 | /* private indicates an unwritten extent lay beneath this IO */ | |
160 | if (private && size > 0) { | |
161 | vnode_t *vp = LINVFS_GET_VP(inode); | |
162 | int error; | |
163 | ||
164 | VOP_BMAP(vp, offset, size, BMAPI_UNWRITTEN, NULL, NULL, error); | |
165 | } | |
166 | } | |
167 | ||
168 | STATIC int | |
169 | xfs_map_blocks( | |
170 | struct inode *inode, | |
171 | loff_t offset, | |
172 | ssize_t count, | |
173 | xfs_iomap_t *mapp, | |
174 | int flags) | |
175 | { | |
176 | vnode_t *vp = LINVFS_GET_VP(inode); | |
177 | int error, nmaps = 1; | |
178 | ||
179 | VOP_BMAP(vp, offset, count, flags, mapp, &nmaps, error); | |
180 | if (!error && (flags & (BMAPI_WRITE|BMAPI_ALLOCATE))) | |
181 | VMODIFY(vp); | |
182 | return -error; | |
183 | } | |
184 | ||
185 | /* | |
186 | * Finds the corresponding mapping in block @map array of the | |
187 | * given @offset within a @page. | |
188 | */ | |
189 | STATIC xfs_iomap_t * | |
190 | xfs_offset_to_map( | |
191 | struct page *page, | |
192 | xfs_iomap_t *iomapp, | |
193 | unsigned long offset) | |
194 | { | |
195 | loff_t full_offset; /* offset from start of file */ | |
196 | ||
197 | ASSERT(offset < PAGE_CACHE_SIZE); | |
198 | ||
199 | full_offset = page->index; /* NB: using 64bit number */ | |
200 | full_offset <<= PAGE_CACHE_SHIFT; /* offset from file start */ | |
201 | full_offset += offset; /* offset from page start */ | |
202 | ||
203 | if (full_offset < iomapp->iomap_offset) | |
204 | return NULL; | |
205 | if (iomapp->iomap_offset + (iomapp->iomap_bsize -1) >= full_offset) | |
206 | return iomapp; | |
207 | return NULL; | |
208 | } | |
209 | ||
210 | STATIC void | |
211 | xfs_map_at_offset( | |
212 | struct page *page, | |
213 | struct buffer_head *bh, | |
214 | unsigned long offset, | |
215 | int block_bits, | |
216 | xfs_iomap_t *iomapp) | |
217 | { | |
218 | xfs_daddr_t bn; | |
219 | loff_t delta; | |
220 | int sector_shift; | |
221 | ||
222 | ASSERT(!(iomapp->iomap_flags & IOMAP_HOLE)); | |
223 | ASSERT(!(iomapp->iomap_flags & IOMAP_DELAY)); | |
224 | ASSERT(iomapp->iomap_bn != IOMAP_DADDR_NULL); | |
225 | ||
226 | delta = page->index; | |
227 | delta <<= PAGE_CACHE_SHIFT; | |
228 | delta += offset; | |
229 | delta -= iomapp->iomap_offset; | |
230 | delta >>= block_bits; | |
231 | ||
232 | sector_shift = block_bits - BBSHIFT; | |
233 | bn = iomapp->iomap_bn >> sector_shift; | |
234 | bn += delta; | |
235 | BUG_ON(!bn && !(iomapp->iomap_flags & IOMAP_REALTIME)); | |
236 | ASSERT((bn << sector_shift) >= iomapp->iomap_bn); | |
237 | ||
238 | lock_buffer(bh); | |
239 | bh->b_blocknr = bn; | |
240 | bh->b_bdev = iomapp->iomap_target->pbr_bdev; | |
241 | set_buffer_mapped(bh); | |
242 | clear_buffer_delay(bh); | |
243 | } | |
244 | ||
245 | /* | |
246 | * Look for a page at index which is unlocked and contains our | |
247 | * unwritten extent flagged buffers at its head. Returns page | |
248 | * locked and with an extra reference count, and length of the | |
249 | * unwritten extent component on this page that we can write, | |
250 | * in units of filesystem blocks. | |
251 | */ | |
252 | STATIC struct page * | |
253 | xfs_probe_unwritten_page( | |
254 | struct address_space *mapping, | |
255 | pgoff_t index, | |
256 | xfs_iomap_t *iomapp, | |
257 | xfs_buf_t *pb, | |
258 | unsigned long max_offset, | |
259 | unsigned long *fsbs, | |
260 | unsigned int bbits) | |
261 | { | |
262 | struct page *page; | |
263 | ||
264 | page = find_trylock_page(mapping, index); | |
265 | if (!page) | |
266 | return NULL; | |
267 | if (PageWriteback(page)) | |
268 | goto out; | |
269 | ||
270 | if (page->mapping && page_has_buffers(page)) { | |
271 | struct buffer_head *bh, *head; | |
272 | unsigned long p_offset = 0; | |
273 | ||
274 | *fsbs = 0; | |
275 | bh = head = page_buffers(page); | |
276 | do { | |
277 | if (!buffer_unwritten(bh) || !buffer_uptodate(bh)) | |
278 | break; | |
279 | if (!xfs_offset_to_map(page, iomapp, p_offset)) | |
280 | break; | |
281 | if (p_offset >= max_offset) | |
282 | break; | |
283 | xfs_map_at_offset(page, bh, p_offset, bbits, iomapp); | |
284 | set_buffer_unwritten_io(bh); | |
285 | bh->b_private = pb; | |
286 | p_offset += bh->b_size; | |
287 | (*fsbs)++; | |
288 | } while ((bh = bh->b_this_page) != head); | |
289 | ||
290 | if (p_offset) | |
291 | return page; | |
292 | } | |
293 | ||
294 | out: | |
295 | unlock_page(page); | |
296 | return NULL; | |
297 | } | |
298 | ||
299 | /* | |
300 | * Look for a page at index which is unlocked and not mapped | |
301 | * yet - clustering for mmap write case. | |
302 | */ | |
303 | STATIC unsigned int | |
304 | xfs_probe_unmapped_page( | |
305 | struct address_space *mapping, | |
306 | pgoff_t index, | |
307 | unsigned int pg_offset) | |
308 | { | |
309 | struct page *page; | |
310 | int ret = 0; | |
311 | ||
312 | page = find_trylock_page(mapping, index); | |
313 | if (!page) | |
314 | return 0; | |
315 | if (PageWriteback(page)) | |
316 | goto out; | |
317 | ||
318 | if (page->mapping && PageDirty(page)) { | |
319 | if (page_has_buffers(page)) { | |
320 | struct buffer_head *bh, *head; | |
321 | ||
322 | bh = head = page_buffers(page); | |
323 | do { | |
324 | if (buffer_mapped(bh) || !buffer_uptodate(bh)) | |
325 | break; | |
326 | ret += bh->b_size; | |
327 | if (ret >= pg_offset) | |
328 | break; | |
329 | } while ((bh = bh->b_this_page) != head); | |
330 | } else | |
331 | ret = PAGE_CACHE_SIZE; | |
332 | } | |
333 | ||
334 | out: | |
335 | unlock_page(page); | |
336 | return ret; | |
337 | } | |
338 | ||
339 | STATIC unsigned int | |
340 | xfs_probe_unmapped_cluster( | |
341 | struct inode *inode, | |
342 | struct page *startpage, | |
343 | struct buffer_head *bh, | |
344 | struct buffer_head *head) | |
345 | { | |
346 | pgoff_t tindex, tlast, tloff; | |
347 | unsigned int pg_offset, len, total = 0; | |
348 | struct address_space *mapping = inode->i_mapping; | |
349 | ||
350 | /* First sum forwards in this page */ | |
351 | do { | |
352 | if (buffer_mapped(bh)) | |
353 | break; | |
354 | total += bh->b_size; | |
355 | } while ((bh = bh->b_this_page) != head); | |
356 | ||
357 | /* If we reached the end of the page, sum forwards in | |
358 | * following pages. | |
359 | */ | |
360 | if (bh == head) { | |
361 | tlast = i_size_read(inode) >> PAGE_CACHE_SHIFT; | |
362 | /* Prune this back to avoid pathological behavior */ | |
363 | tloff = min(tlast, startpage->index + 64); | |
364 | for (tindex = startpage->index + 1; tindex < tloff; tindex++) { | |
365 | len = xfs_probe_unmapped_page(mapping, tindex, | |
366 | PAGE_CACHE_SIZE); | |
367 | if (!len) | |
368 | return total; | |
369 | total += len; | |
370 | } | |
371 | if (tindex == tlast && | |
372 | (pg_offset = i_size_read(inode) & (PAGE_CACHE_SIZE - 1))) { | |
373 | total += xfs_probe_unmapped_page(mapping, | |
374 | tindex, pg_offset); | |
375 | } | |
376 | } | |
377 | return total; | |
378 | } | |
379 | ||
380 | /* | |
381 | * Probe for a given page (index) in the inode and test if it is delayed | |
382 | * and without unwritten buffers. Returns page locked and with an extra | |
383 | * reference count. | |
384 | */ | |
385 | STATIC struct page * | |
386 | xfs_probe_delalloc_page( | |
387 | struct inode *inode, | |
388 | pgoff_t index) | |
389 | { | |
390 | struct page *page; | |
391 | ||
392 | page = find_trylock_page(inode->i_mapping, index); | |
393 | if (!page) | |
394 | return NULL; | |
395 | if (PageWriteback(page)) | |
396 | goto out; | |
397 | ||
398 | if (page->mapping && page_has_buffers(page)) { | |
399 | struct buffer_head *bh, *head; | |
400 | int acceptable = 0; | |
401 | ||
402 | bh = head = page_buffers(page); | |
403 | do { | |
404 | if (buffer_unwritten(bh)) { | |
405 | acceptable = 0; | |
406 | break; | |
407 | } else if (buffer_delay(bh)) { | |
408 | acceptable = 1; | |
409 | } | |
410 | } while ((bh = bh->b_this_page) != head); | |
411 | ||
412 | if (acceptable) | |
413 | return page; | |
414 | } | |
415 | ||
416 | out: | |
417 | unlock_page(page); | |
418 | return NULL; | |
419 | } | |
420 | ||
421 | STATIC int | |
422 | xfs_map_unwritten( | |
423 | struct inode *inode, | |
424 | struct page *start_page, | |
425 | struct buffer_head *head, | |
426 | struct buffer_head *curr, | |
427 | unsigned long p_offset, | |
428 | int block_bits, | |
429 | xfs_iomap_t *iomapp, | |
430 | struct writeback_control *wbc, | |
431 | int startio, | |
432 | int all_bh) | |
433 | { | |
434 | struct buffer_head *bh = curr; | |
435 | xfs_iomap_t *tmp; | |
436 | xfs_buf_t *pb; | |
437 | loff_t offset, size; | |
438 | unsigned long nblocks = 0; | |
439 | ||
440 | offset = start_page->index; | |
441 | offset <<= PAGE_CACHE_SHIFT; | |
442 | offset += p_offset; | |
443 | ||
444 | /* get an "empty" pagebuf to manage IO completion | |
445 | * Proper values will be set before returning */ | |
446 | pb = pagebuf_lookup(iomapp->iomap_target, 0, 0, 0); | |
447 | if (!pb) | |
448 | return -EAGAIN; | |
449 | ||
450 | /* Take a reference to the inode to prevent it from | |
451 | * being reclaimed while we have outstanding unwritten | |
452 | * extent IO on it. | |
453 | */ | |
454 | if ((igrab(inode)) != inode) { | |
455 | pagebuf_free(pb); | |
456 | return -EAGAIN; | |
457 | } | |
458 | ||
459 | /* Set the count to 1 initially, this will stop an I/O | |
460 | * completion callout which happens before we have started | |
461 | * all the I/O from calling pagebuf_iodone too early. | |
462 | */ | |
463 | atomic_set(&pb->pb_io_remaining, 1); | |
464 | ||
465 | /* First map forwards in the page consecutive buffers | |
466 | * covering this unwritten extent | |
467 | */ | |
468 | do { | |
469 | if (!buffer_unwritten(bh)) | |
470 | break; | |
471 | tmp = xfs_offset_to_map(start_page, iomapp, p_offset); | |
472 | if (!tmp) | |
473 | break; | |
474 | xfs_map_at_offset(start_page, bh, p_offset, block_bits, iomapp); | |
475 | set_buffer_unwritten_io(bh); | |
476 | bh->b_private = pb; | |
477 | p_offset += bh->b_size; | |
478 | nblocks++; | |
479 | } while ((bh = bh->b_this_page) != head); | |
480 | ||
481 | atomic_add(nblocks, &pb->pb_io_remaining); | |
482 | ||
483 | /* If we reached the end of the page, map forwards in any | |
484 | * following pages which are also covered by this extent. | |
485 | */ | |
486 | if (bh == head) { | |
487 | struct address_space *mapping = inode->i_mapping; | |
488 | pgoff_t tindex, tloff, tlast; | |
489 | unsigned long bs; | |
490 | unsigned int pg_offset, bbits = inode->i_blkbits; | |
491 | struct page *page; | |
492 | ||
493 | tlast = i_size_read(inode) >> PAGE_CACHE_SHIFT; | |
494 | tloff = (iomapp->iomap_offset + iomapp->iomap_bsize) >> PAGE_CACHE_SHIFT; | |
495 | tloff = min(tlast, tloff); | |
496 | for (tindex = start_page->index + 1; tindex < tloff; tindex++) { | |
497 | page = xfs_probe_unwritten_page(mapping, | |
498 | tindex, iomapp, pb, | |
499 | PAGE_CACHE_SIZE, &bs, bbits); | |
500 | if (!page) | |
501 | break; | |
502 | nblocks += bs; | |
503 | atomic_add(bs, &pb->pb_io_remaining); | |
504 | xfs_convert_page(inode, page, iomapp, wbc, pb, | |
505 | startio, all_bh); | |
506 | /* stop if converting the next page might add | |
507 | * enough blocks that the corresponding byte | |
508 | * count won't fit in our ulong page buf length */ | |
509 | if (nblocks >= ((ULONG_MAX - PAGE_SIZE) >> block_bits)) | |
510 | goto enough; | |
511 | } | |
512 | ||
513 | if (tindex == tlast && | |
514 | (pg_offset = (i_size_read(inode) & (PAGE_CACHE_SIZE - 1)))) { | |
515 | page = xfs_probe_unwritten_page(mapping, | |
516 | tindex, iomapp, pb, | |
517 | pg_offset, &bs, bbits); | |
518 | if (page) { | |
519 | nblocks += bs; | |
520 | atomic_add(bs, &pb->pb_io_remaining); | |
521 | xfs_convert_page(inode, page, iomapp, wbc, pb, | |
522 | startio, all_bh); | |
523 | if (nblocks >= ((ULONG_MAX - PAGE_SIZE) >> block_bits)) | |
524 | goto enough; | |
525 | } | |
526 | } | |
527 | } | |
528 | ||
529 | enough: | |
530 | size = nblocks; /* NB: using 64bit number here */ | |
531 | size <<= block_bits; /* convert fsb's to byte range */ | |
532 | ||
533 | XFS_BUF_DATAIO(pb); | |
534 | XFS_BUF_ASYNC(pb); | |
535 | XFS_BUF_SET_SIZE(pb, size); | |
536 | XFS_BUF_SET_COUNT(pb, size); | |
537 | XFS_BUF_SET_OFFSET(pb, offset); | |
538 | XFS_BUF_SET_FSPRIVATE(pb, LINVFS_GET_VP(inode)); | |
539 | XFS_BUF_SET_IODONE_FUNC(pb, linvfs_unwritten_convert); | |
540 | ||
541 | if (atomic_dec_and_test(&pb->pb_io_remaining) == 1) { | |
542 | pagebuf_iodone(pb, 1, 1); | |
543 | } | |
544 | ||
545 | return 0; | |
546 | } | |
547 | ||
548 | STATIC void | |
549 | xfs_submit_page( | |
550 | struct page *page, | |
551 | struct writeback_control *wbc, | |
552 | struct buffer_head *bh_arr[], | |
553 | int bh_count, | |
554 | int probed_page, | |
555 | int clear_dirty) | |
556 | { | |
557 | struct buffer_head *bh; | |
558 | int i; | |
559 | ||
560 | BUG_ON(PageWriteback(page)); | |
561 | set_page_writeback(page); | |
562 | if (clear_dirty) | |
563 | clear_page_dirty(page); | |
564 | unlock_page(page); | |
565 | ||
566 | if (bh_count) { | |
567 | for (i = 0; i < bh_count; i++) { | |
568 | bh = bh_arr[i]; | |
569 | mark_buffer_async_write(bh); | |
570 | if (buffer_unwritten(bh)) | |
571 | set_buffer_unwritten_io(bh); | |
572 | set_buffer_uptodate(bh); | |
573 | clear_buffer_dirty(bh); | |
574 | } | |
575 | ||
576 | for (i = 0; i < bh_count; i++) | |
577 | submit_bh(WRITE, bh_arr[i]); | |
578 | ||
579 | if (probed_page && clear_dirty) | |
580 | wbc->nr_to_write--; /* Wrote an "extra" page */ | |
581 | } else { | |
582 | end_page_writeback(page); | |
583 | wbc->pages_skipped++; /* We didn't write this page */ | |
584 | } | |
585 | } | |
586 | ||
587 | /* | |
588 | * Allocate & map buffers for page given the extent map. Write it out. | |
589 | * except for the original page of a writepage, this is called on | |
590 | * delalloc/unwritten pages only, for the original page it is possible | |
591 | * that the page has no mapping at all. | |
592 | */ | |
593 | STATIC void | |
594 | xfs_convert_page( | |
595 | struct inode *inode, | |
596 | struct page *page, | |
597 | xfs_iomap_t *iomapp, | |
598 | struct writeback_control *wbc, | |
599 | void *private, | |
600 | int startio, | |
601 | int all_bh) | |
602 | { | |
603 | struct buffer_head *bh_arr[MAX_BUF_PER_PAGE], *bh, *head; | |
604 | xfs_iomap_t *mp = iomapp, *tmp; | |
605 | unsigned long end, offset; | |
606 | pgoff_t end_index; | |
607 | int i = 0, index = 0; | |
608 | int bbits = inode->i_blkbits; | |
609 | ||
610 | end_index = i_size_read(inode) >> PAGE_CACHE_SHIFT; | |
611 | if (page->index < end_index) { | |
612 | end = PAGE_CACHE_SIZE; | |
613 | } else { | |
614 | end = i_size_read(inode) & (PAGE_CACHE_SIZE-1); | |
615 | } | |
616 | bh = head = page_buffers(page); | |
617 | do { | |
618 | offset = i << bbits; | |
619 | if (offset >= end) | |
620 | break; | |
621 | if (!(PageUptodate(page) || buffer_uptodate(bh))) | |
622 | continue; | |
623 | if (buffer_mapped(bh) && all_bh && | |
624 | !(buffer_unwritten(bh) || buffer_delay(bh))) { | |
625 | if (startio) { | |
626 | lock_buffer(bh); | |
627 | bh_arr[index++] = bh; | |
628 | } | |
629 | continue; | |
630 | } | |
631 | tmp = xfs_offset_to_map(page, mp, offset); | |
632 | if (!tmp) | |
633 | continue; | |
634 | ASSERT(!(tmp->iomap_flags & IOMAP_HOLE)); | |
635 | ASSERT(!(tmp->iomap_flags & IOMAP_DELAY)); | |
636 | ||
637 | /* If this is a new unwritten extent buffer (i.e. one | |
638 | * that we haven't passed in private data for, we must | |
639 | * now map this buffer too. | |
640 | */ | |
641 | if (buffer_unwritten(bh) && !bh->b_end_io) { | |
642 | ASSERT(tmp->iomap_flags & IOMAP_UNWRITTEN); | |
643 | xfs_map_unwritten(inode, page, head, bh, offset, | |
644 | bbits, tmp, wbc, startio, all_bh); | |
645 | } else if (! (buffer_unwritten(bh) && buffer_locked(bh))) { | |
646 | xfs_map_at_offset(page, bh, offset, bbits, tmp); | |
647 | if (buffer_unwritten(bh)) { | |
648 | set_buffer_unwritten_io(bh); | |
649 | bh->b_private = private; | |
650 | ASSERT(private); | |
651 | } | |
652 | } | |
653 | if (startio) { | |
654 | bh_arr[index++] = bh; | |
655 | } else { | |
656 | set_buffer_dirty(bh); | |
657 | unlock_buffer(bh); | |
658 | mark_buffer_dirty(bh); | |
659 | } | |
660 | } while (i++, (bh = bh->b_this_page) != head); | |
661 | ||
662 | if (startio) { | |
663 | xfs_submit_page(page, wbc, bh_arr, index, 1, index == i); | |
664 | } else { | |
665 | unlock_page(page); | |
666 | } | |
667 | } | |
668 | ||
669 | /* | |
670 | * Convert & write out a cluster of pages in the same extent as defined | |
671 | * by mp and following the start page. | |
672 | */ | |
673 | STATIC void | |
674 | xfs_cluster_write( | |
675 | struct inode *inode, | |
676 | pgoff_t tindex, | |
677 | xfs_iomap_t *iomapp, | |
678 | struct writeback_control *wbc, | |
679 | int startio, | |
680 | int all_bh, | |
681 | pgoff_t tlast) | |
682 | { | |
683 | struct page *page; | |
684 | ||
685 | for (; tindex <= tlast; tindex++) { | |
686 | page = xfs_probe_delalloc_page(inode, tindex); | |
687 | if (!page) | |
688 | break; | |
689 | xfs_convert_page(inode, page, iomapp, wbc, NULL, | |
690 | startio, all_bh); | |
691 | } | |
692 | } | |
693 | ||
694 | /* | |
695 | * Calling this without startio set means we are being asked to make a dirty | |
696 | * page ready for freeing it's buffers. When called with startio set then | |
697 | * we are coming from writepage. | |
698 | * | |
699 | * When called with startio set it is important that we write the WHOLE | |
700 | * page if possible. | |
701 | * The bh->b_state's cannot know if any of the blocks or which block for | |
702 | * that matter are dirty due to mmap writes, and therefore bh uptodate is | |
703 | * only vaild if the page itself isn't completely uptodate. Some layers | |
704 | * may clear the page dirty flag prior to calling write page, under the | |
705 | * assumption the entire page will be written out; by not writing out the | |
706 | * whole page the page can be reused before all valid dirty data is | |
707 | * written out. Note: in the case of a page that has been dirty'd by | |
708 | * mapwrite and but partially setup by block_prepare_write the | |
709 | * bh->b_states's will not agree and only ones setup by BPW/BCW will have | |
710 | * valid state, thus the whole page must be written out thing. | |
711 | */ | |
712 | ||
713 | STATIC int | |
714 | xfs_page_state_convert( | |
715 | struct inode *inode, | |
716 | struct page *page, | |
717 | struct writeback_control *wbc, | |
718 | int startio, | |
719 | int unmapped) /* also implies page uptodate */ | |
720 | { | |
721 | struct buffer_head *bh_arr[MAX_BUF_PER_PAGE], *bh, *head; | |
722 | xfs_iomap_t *iomp, iomap; | |
723 | loff_t offset; | |
724 | unsigned long p_offset = 0; | |
725 | __uint64_t end_offset; | |
726 | pgoff_t end_index, last_index, tlast; | |
727 | int len, err, i, cnt = 0, uptodate = 1; | |
3ba0815a | 728 | int flags; |
775bf6c9 | 729 | int page_dirty; |
1da177e4 | 730 | |
3ba0815a DM |
731 | /* wait for other IO threads? */ |
732 | flags = (startio && wbc->sync_mode != WB_SYNC_NONE) ? 0 : BMAPI_TRYLOCK; | |
733 | ||
1da177e4 LT |
734 | /* Is this page beyond the end of the file? */ |
735 | offset = i_size_read(inode); | |
736 | end_index = offset >> PAGE_CACHE_SHIFT; | |
737 | last_index = (offset - 1) >> PAGE_CACHE_SHIFT; | |
738 | if (page->index >= end_index) { | |
739 | if ((page->index >= end_index + 1) || | |
740 | !(i_size_read(inode) & (PAGE_CACHE_SIZE - 1))) { | |
741 | err = -EIO; | |
742 | goto error; | |
743 | } | |
744 | } | |
745 | ||
746 | offset = (loff_t)page->index << PAGE_CACHE_SHIFT; | |
747 | end_offset = min_t(unsigned long long, | |
748 | offset + PAGE_CACHE_SIZE, i_size_read(inode)); | |
749 | ||
750 | bh = head = page_buffers(page); | |
751 | iomp = NULL; | |
752 | ||
753 | /* | |
754 | * page_dirty is initially a count of buffers on the page and | |
755 | * is decrememted as we move each into a cleanable state. | |
756 | */ | |
757 | len = bh->b_size; | |
758 | page_dirty = PAGE_CACHE_SIZE / len; | |
759 | ||
760 | do { | |
761 | if (offset >= end_offset) | |
762 | break; | |
763 | if (!buffer_uptodate(bh)) | |
764 | uptodate = 0; | |
765 | if (!(PageUptodate(page) || buffer_uptodate(bh)) && !startio) | |
766 | continue; | |
767 | ||
768 | if (iomp) { | |
769 | iomp = xfs_offset_to_map(page, &iomap, p_offset); | |
770 | } | |
771 | ||
772 | /* | |
773 | * First case, map an unwritten extent and prepare for | |
774 | * extent state conversion transaction on completion. | |
775 | */ | |
776 | if (buffer_unwritten(bh)) { | |
777 | if (!startio) | |
778 | continue; | |
779 | if (!iomp) { | |
780 | err = xfs_map_blocks(inode, offset, len, &iomap, | |
781 | BMAPI_READ|BMAPI_IGNSTATE); | |
782 | if (err) { | |
783 | goto error; | |
784 | } | |
785 | iomp = xfs_offset_to_map(page, &iomap, | |
786 | p_offset); | |
787 | } | |
788 | if (iomp) { | |
789 | if (!bh->b_end_io) { | |
790 | err = xfs_map_unwritten(inode, page, | |
791 | head, bh, p_offset, | |
792 | inode->i_blkbits, iomp, | |
793 | wbc, startio, unmapped); | |
794 | if (err) { | |
795 | goto error; | |
796 | } | |
797 | } else { | |
798 | set_bit(BH_Lock, &bh->b_state); | |
799 | } | |
800 | BUG_ON(!buffer_locked(bh)); | |
801 | bh_arr[cnt++] = bh; | |
802 | page_dirty--; | |
803 | } | |
804 | /* | |
805 | * Second case, allocate space for a delalloc buffer. | |
806 | * We can return EAGAIN here in the release page case. | |
807 | */ | |
808 | } else if (buffer_delay(bh)) { | |
809 | if (!iomp) { | |
1da177e4 LT |
810 | err = xfs_map_blocks(inode, offset, len, &iomap, |
811 | BMAPI_ALLOCATE | flags); | |
812 | if (err) { | |
813 | goto error; | |
814 | } | |
815 | iomp = xfs_offset_to_map(page, &iomap, | |
816 | p_offset); | |
817 | } | |
818 | if (iomp) { | |
819 | xfs_map_at_offset(page, bh, p_offset, | |
820 | inode->i_blkbits, iomp); | |
821 | if (startio) { | |
822 | bh_arr[cnt++] = bh; | |
823 | } else { | |
824 | set_buffer_dirty(bh); | |
825 | unlock_buffer(bh); | |
826 | mark_buffer_dirty(bh); | |
827 | } | |
828 | page_dirty--; | |
829 | } | |
830 | } else if ((buffer_uptodate(bh) || PageUptodate(page)) && | |
831 | (unmapped || startio)) { | |
832 | ||
833 | if (!buffer_mapped(bh)) { | |
834 | int size; | |
835 | ||
836 | /* | |
837 | * Getting here implies an unmapped buffer | |
838 | * was found, and we are in a path where we | |
839 | * need to write the whole page out. | |
840 | */ | |
841 | if (!iomp) { | |
842 | size = xfs_probe_unmapped_cluster( | |
843 | inode, page, bh, head); | |
844 | err = xfs_map_blocks(inode, offset, | |
845 | size, &iomap, | |
846 | BMAPI_WRITE|BMAPI_MMAP); | |
847 | if (err) { | |
848 | goto error; | |
849 | } | |
850 | iomp = xfs_offset_to_map(page, &iomap, | |
851 | p_offset); | |
852 | } | |
853 | if (iomp) { | |
854 | xfs_map_at_offset(page, | |
855 | bh, p_offset, | |
856 | inode->i_blkbits, iomp); | |
857 | if (startio) { | |
858 | bh_arr[cnt++] = bh; | |
859 | } else { | |
860 | set_buffer_dirty(bh); | |
861 | unlock_buffer(bh); | |
862 | mark_buffer_dirty(bh); | |
863 | } | |
864 | page_dirty--; | |
865 | } | |
866 | } else if (startio) { | |
867 | if (buffer_uptodate(bh) && | |
868 | !test_and_set_bit(BH_Lock, &bh->b_state)) { | |
869 | bh_arr[cnt++] = bh; | |
870 | page_dirty--; | |
871 | } | |
872 | } | |
873 | } | |
874 | } while (offset += len, p_offset += len, | |
875 | ((bh = bh->b_this_page) != head)); | |
876 | ||
877 | if (uptodate && bh == head) | |
878 | SetPageUptodate(page); | |
879 | ||
880 | if (startio) | |
881 | xfs_submit_page(page, wbc, bh_arr, cnt, 0, 1); | |
882 | ||
883 | if (iomp) { | |
775bf6c9 | 884 | offset = (iomp->iomap_offset + iomp->iomap_bsize - 1) >> |
1da177e4 | 885 | PAGE_CACHE_SHIFT; |
775bf6c9 | 886 | tlast = min_t(pgoff_t, offset, last_index); |
1da177e4 LT |
887 | xfs_cluster_write(inode, page->index + 1, iomp, wbc, |
888 | startio, unmapped, tlast); | |
889 | } | |
890 | ||
891 | return page_dirty; | |
892 | ||
893 | error: | |
894 | for (i = 0; i < cnt; i++) { | |
895 | unlock_buffer(bh_arr[i]); | |
896 | } | |
897 | ||
898 | /* | |
899 | * If it's delalloc and we have nowhere to put it, | |
900 | * throw it away, unless the lower layers told | |
901 | * us to try again. | |
902 | */ | |
903 | if (err != -EAGAIN) { | |
904 | if (!unmapped) { | |
905 | block_invalidatepage(page, 0); | |
906 | } | |
907 | ClearPageUptodate(page); | |
908 | } | |
909 | return err; | |
910 | } | |
911 | ||
912 | STATIC int | |
913 | __linvfs_get_block( | |
914 | struct inode *inode, | |
915 | sector_t iblock, | |
916 | unsigned long blocks, | |
917 | struct buffer_head *bh_result, | |
918 | int create, | |
919 | int direct, | |
920 | bmapi_flags_t flags) | |
921 | { | |
922 | vnode_t *vp = LINVFS_GET_VP(inode); | |
923 | xfs_iomap_t iomap; | |
924 | int retpbbm = 1; | |
925 | int error; | |
926 | ssize_t size; | |
927 | loff_t offset = (loff_t)iblock << inode->i_blkbits; | |
928 | ||
929 | if (blocks) | |
930 | size = blocks << inode->i_blkbits; | |
931 | else | |
932 | size = 1 << inode->i_blkbits; | |
933 | ||
934 | VOP_BMAP(vp, offset, size, | |
935 | create ? flags : BMAPI_READ, &iomap, &retpbbm, error); | |
936 | if (error) | |
937 | return -error; | |
938 | ||
939 | if (retpbbm == 0) | |
940 | return 0; | |
941 | ||
942 | if (iomap.iomap_bn != IOMAP_DADDR_NULL) { | |
943 | xfs_daddr_t bn; | |
944 | loff_t delta; | |
945 | ||
946 | /* For unwritten extents do not report a disk address on | |
947 | * the read case (treat as if we're reading into a hole). | |
948 | */ | |
949 | if (create || !(iomap.iomap_flags & IOMAP_UNWRITTEN)) { | |
950 | delta = offset - iomap.iomap_offset; | |
951 | delta >>= inode->i_blkbits; | |
952 | ||
953 | bn = iomap.iomap_bn >> (inode->i_blkbits - BBSHIFT); | |
954 | bn += delta; | |
955 | BUG_ON(!bn && !(iomap.iomap_flags & IOMAP_REALTIME)); | |
956 | bh_result->b_blocknr = bn; | |
957 | set_buffer_mapped(bh_result); | |
958 | } | |
959 | if (create && (iomap.iomap_flags & IOMAP_UNWRITTEN)) { | |
960 | if (direct) | |
961 | bh_result->b_private = inode; | |
962 | set_buffer_unwritten(bh_result); | |
963 | set_buffer_delay(bh_result); | |
964 | } | |
965 | } | |
966 | ||
967 | /* If this is a realtime file, data might be on a new device */ | |
968 | bh_result->b_bdev = iomap.iomap_target->pbr_bdev; | |
969 | ||
970 | /* If we previously allocated a block out beyond eof and | |
971 | * we are now coming back to use it then we will need to | |
972 | * flag it as new even if it has a disk address. | |
973 | */ | |
974 | if (create && | |
975 | ((!buffer_mapped(bh_result) && !buffer_uptodate(bh_result)) || | |
976 | (offset >= i_size_read(inode)) || (iomap.iomap_flags & IOMAP_NEW))) { | |
977 | set_buffer_new(bh_result); | |
978 | } | |
979 | ||
980 | if (iomap.iomap_flags & IOMAP_DELAY) { | |
981 | BUG_ON(direct); | |
982 | if (create) { | |
983 | set_buffer_uptodate(bh_result); | |
984 | set_buffer_mapped(bh_result); | |
985 | set_buffer_delay(bh_result); | |
986 | } | |
987 | } | |
988 | ||
989 | if (blocks) { | |
990 | bh_result->b_size = (ssize_t)min( | |
991 | (loff_t)(iomap.iomap_bsize - iomap.iomap_delta), | |
992 | (loff_t)(blocks << inode->i_blkbits)); | |
993 | } | |
994 | ||
995 | return 0; | |
996 | } | |
997 | ||
998 | int | |
999 | linvfs_get_block( | |
1000 | struct inode *inode, | |
1001 | sector_t iblock, | |
1002 | struct buffer_head *bh_result, | |
1003 | int create) | |
1004 | { | |
1005 | return __linvfs_get_block(inode, iblock, 0, bh_result, | |
1006 | create, 0, BMAPI_WRITE); | |
1007 | } | |
1008 | ||
1009 | STATIC int | |
1010 | linvfs_get_blocks_direct( | |
1011 | struct inode *inode, | |
1012 | sector_t iblock, | |
1013 | unsigned long max_blocks, | |
1014 | struct buffer_head *bh_result, | |
1015 | int create) | |
1016 | { | |
1017 | return __linvfs_get_block(inode, iblock, max_blocks, bh_result, | |
1018 | create, 1, BMAPI_WRITE|BMAPI_DIRECT); | |
1019 | } | |
1020 | ||
1021 | STATIC ssize_t | |
1022 | linvfs_direct_IO( | |
1023 | int rw, | |
1024 | struct kiocb *iocb, | |
1025 | const struct iovec *iov, | |
1026 | loff_t offset, | |
1027 | unsigned long nr_segs) | |
1028 | { | |
1029 | struct file *file = iocb->ki_filp; | |
1030 | struct inode *inode = file->f_mapping->host; | |
1031 | vnode_t *vp = LINVFS_GET_VP(inode); | |
1032 | xfs_iomap_t iomap; | |
1033 | int maps = 1; | |
1034 | int error; | |
1035 | ||
1036 | VOP_BMAP(vp, offset, 0, BMAPI_DEVICE, &iomap, &maps, error); | |
1037 | if (error) | |
1038 | return -error; | |
1039 | ||
1040 | return blockdev_direct_IO_own_locking(rw, iocb, inode, | |
1041 | iomap.iomap_target->pbr_bdev, | |
1042 | iov, offset, nr_segs, | |
1043 | linvfs_get_blocks_direct, | |
1044 | linvfs_unwritten_convert_direct); | |
1045 | } | |
1046 | ||
1047 | ||
1048 | STATIC sector_t | |
1049 | linvfs_bmap( | |
1050 | struct address_space *mapping, | |
1051 | sector_t block) | |
1052 | { | |
1053 | struct inode *inode = (struct inode *)mapping->host; | |
1054 | vnode_t *vp = LINVFS_GET_VP(inode); | |
1055 | int error; | |
1056 | ||
1057 | vn_trace_entry(vp, "linvfs_bmap", (inst_t *)__return_address); | |
1058 | ||
1059 | VOP_RWLOCK(vp, VRWLOCK_READ); | |
1060 | VOP_FLUSH_PAGES(vp, (xfs_off_t)0, -1, 0, FI_REMAPF, error); | |
1061 | VOP_RWUNLOCK(vp, VRWLOCK_READ); | |
1062 | return generic_block_bmap(mapping, block, linvfs_get_block); | |
1063 | } | |
1064 | ||
1065 | STATIC int | |
1066 | linvfs_readpage( | |
1067 | struct file *unused, | |
1068 | struct page *page) | |
1069 | { | |
1070 | return mpage_readpage(page, linvfs_get_block); | |
1071 | } | |
1072 | ||
1073 | STATIC int | |
1074 | linvfs_readpages( | |
1075 | struct file *unused, | |
1076 | struct address_space *mapping, | |
1077 | struct list_head *pages, | |
1078 | unsigned nr_pages) | |
1079 | { | |
1080 | return mpage_readpages(mapping, pages, nr_pages, linvfs_get_block); | |
1081 | } | |
1082 | ||
1083 | STATIC void | |
1084 | xfs_count_page_state( | |
1085 | struct page *page, | |
1086 | int *delalloc, | |
1087 | int *unmapped, | |
1088 | int *unwritten) | |
1089 | { | |
1090 | struct buffer_head *bh, *head; | |
1091 | ||
1092 | *delalloc = *unmapped = *unwritten = 0; | |
1093 | ||
1094 | bh = head = page_buffers(page); | |
1095 | do { | |
1096 | if (buffer_uptodate(bh) && !buffer_mapped(bh)) | |
1097 | (*unmapped) = 1; | |
1098 | else if (buffer_unwritten(bh) && !buffer_delay(bh)) | |
1099 | clear_buffer_unwritten(bh); | |
1100 | else if (buffer_unwritten(bh)) | |
1101 | (*unwritten) = 1; | |
1102 | else if (buffer_delay(bh)) | |
1103 | (*delalloc) = 1; | |
1104 | } while ((bh = bh->b_this_page) != head); | |
1105 | } | |
1106 | ||
1107 | ||
1108 | /* | |
1109 | * writepage: Called from one of two places: | |
1110 | * | |
1111 | * 1. we are flushing a delalloc buffer head. | |
1112 | * | |
1113 | * 2. we are writing out a dirty page. Typically the page dirty | |
1114 | * state is cleared before we get here. In this case is it | |
1115 | * conceivable we have no buffer heads. | |
1116 | * | |
1117 | * For delalloc space on the page we need to allocate space and | |
1118 | * flush it. For unmapped buffer heads on the page we should | |
1119 | * allocate space if the page is uptodate. For any other dirty | |
1120 | * buffer heads on the page we should flush them. | |
1121 | * | |
1122 | * If we detect that a transaction would be required to flush | |
1123 | * the page, we have to check the process flags first, if we | |
1124 | * are already in a transaction or disk I/O during allocations | |
1125 | * is off, we need to fail the writepage and redirty the page. | |
1126 | */ | |
1127 | ||
1128 | STATIC int | |
1129 | linvfs_writepage( | |
1130 | struct page *page, | |
1131 | struct writeback_control *wbc) | |
1132 | { | |
1133 | int error; | |
1134 | int need_trans; | |
1135 | int delalloc, unmapped, unwritten; | |
1136 | struct inode *inode = page->mapping->host; | |
1137 | ||
1138 | xfs_page_trace(XFS_WRITEPAGE_ENTER, inode, page, 0); | |
1139 | ||
1140 | /* | |
1141 | * We need a transaction if: | |
1142 | * 1. There are delalloc buffers on the page | |
1143 | * 2. The page is uptodate and we have unmapped buffers | |
1144 | * 3. The page is uptodate and we have no buffers | |
1145 | * 4. There are unwritten buffers on the page | |
1146 | */ | |
1147 | ||
1148 | if (!page_has_buffers(page)) { | |
1149 | unmapped = 1; | |
1150 | need_trans = 1; | |
1151 | } else { | |
1152 | xfs_count_page_state(page, &delalloc, &unmapped, &unwritten); | |
1153 | if (!PageUptodate(page)) | |
1154 | unmapped = 0; | |
1155 | need_trans = delalloc + unmapped + unwritten; | |
1156 | } | |
1157 | ||
1158 | /* | |
1159 | * If we need a transaction and the process flags say | |
1160 | * we are already in a transaction, or no IO is allowed | |
1161 | * then mark the page dirty again and leave the page | |
1162 | * as is. | |
1163 | */ | |
1164 | if (PFLAGS_TEST_FSTRANS() && need_trans) | |
1165 | goto out_fail; | |
1166 | ||
1167 | /* | |
1168 | * Delay hooking up buffer heads until we have | |
1169 | * made our go/no-go decision. | |
1170 | */ | |
1171 | if (!page_has_buffers(page)) | |
1172 | create_empty_buffers(page, 1 << inode->i_blkbits, 0); | |
1173 | ||
1174 | /* | |
1175 | * Convert delayed allocate, unwritten or unmapped space | |
1176 | * to real space and flush out to disk. | |
1177 | */ | |
1178 | error = xfs_page_state_convert(inode, page, wbc, 1, unmapped); | |
1179 | if (error == -EAGAIN) | |
1180 | goto out_fail; | |
1181 | if (unlikely(error < 0)) | |
1182 | goto out_unlock; | |
1183 | ||
1184 | return 0; | |
1185 | ||
1186 | out_fail: | |
1187 | redirty_page_for_writepage(wbc, page); | |
1188 | unlock_page(page); | |
1189 | return 0; | |
1190 | out_unlock: | |
1191 | unlock_page(page); | |
1192 | return error; | |
1193 | } | |
1194 | ||
1195 | /* | |
1196 | * Called to move a page into cleanable state - and from there | |
1197 | * to be released. Possibly the page is already clean. We always | |
1198 | * have buffer heads in this call. | |
1199 | * | |
1200 | * Returns 0 if the page is ok to release, 1 otherwise. | |
1201 | * | |
1202 | * Possible scenarios are: | |
1203 | * | |
1204 | * 1. We are being called to release a page which has been written | |
1205 | * to via regular I/O. buffer heads will be dirty and possibly | |
1206 | * delalloc. If no delalloc buffer heads in this case then we | |
1207 | * can just return zero. | |
1208 | * | |
1209 | * 2. We are called to release a page which has been written via | |
1210 | * mmap, all we need to do is ensure there is no delalloc | |
1211 | * state in the buffer heads, if not we can let the caller | |
1212 | * free them and we should come back later via writepage. | |
1213 | */ | |
1214 | STATIC int | |
1215 | linvfs_release_page( | |
1216 | struct page *page, | |
1217 | int gfp_mask) | |
1218 | { | |
1219 | struct inode *inode = page->mapping->host; | |
1220 | int dirty, delalloc, unmapped, unwritten; | |
1221 | struct writeback_control wbc = { | |
1222 | .sync_mode = WB_SYNC_ALL, | |
1223 | .nr_to_write = 1, | |
1224 | }; | |
1225 | ||
1226 | xfs_page_trace(XFS_RELEASEPAGE_ENTER, inode, page, gfp_mask); | |
1227 | ||
1228 | xfs_count_page_state(page, &delalloc, &unmapped, &unwritten); | |
1229 | if (!delalloc && !unwritten) | |
1230 | goto free_buffers; | |
1231 | ||
1232 | if (!(gfp_mask & __GFP_FS)) | |
1233 | return 0; | |
1234 | ||
1235 | /* If we are already inside a transaction or the thread cannot | |
1236 | * do I/O, we cannot release this page. | |
1237 | */ | |
1238 | if (PFLAGS_TEST_FSTRANS()) | |
1239 | return 0; | |
1240 | ||
1241 | /* | |
1242 | * Convert delalloc space to real space, do not flush the | |
1243 | * data out to disk, that will be done by the caller. | |
1244 | * Never need to allocate space here - we will always | |
1245 | * come back to writepage in that case. | |
1246 | */ | |
1247 | dirty = xfs_page_state_convert(inode, page, &wbc, 0, 0); | |
1248 | if (dirty == 0 && !unwritten) | |
1249 | goto free_buffers; | |
1250 | return 0; | |
1251 | ||
1252 | free_buffers: | |
1253 | return try_to_free_buffers(page); | |
1254 | } | |
1255 | ||
1256 | STATIC int | |
1257 | linvfs_prepare_write( | |
1258 | struct file *file, | |
1259 | struct page *page, | |
1260 | unsigned int from, | |
1261 | unsigned int to) | |
1262 | { | |
1263 | return block_prepare_write(page, from, to, linvfs_get_block); | |
1264 | } | |
1265 | ||
1266 | struct address_space_operations linvfs_aops = { | |
1267 | .readpage = linvfs_readpage, | |
1268 | .readpages = linvfs_readpages, | |
1269 | .writepage = linvfs_writepage, | |
1270 | .sync_page = block_sync_page, | |
1271 | .releasepage = linvfs_release_page, | |
1272 | .prepare_write = linvfs_prepare_write, | |
1273 | .commit_write = generic_commit_write, | |
1274 | .bmap = linvfs_bmap, | |
1275 | .direct_IO = linvfs_direct_IO, | |
1276 | }; |