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1d3576fd SW |
1 | #include "ceph_debug.h" |
2 | ||
3 | #include <linux/backing-dev.h> | |
4 | #include <linux/fs.h> | |
5 | #include <linux/mm.h> | |
6 | #include <linux/pagemap.h> | |
7 | #include <linux/writeback.h> /* generic_writepages */ | |
8 | #include <linux/pagevec.h> | |
9 | #include <linux/task_io_accounting_ops.h> | |
10 | ||
11 | #include "super.h" | |
12 | #include "osd_client.h" | |
13 | ||
14 | /* | |
15 | * Ceph address space ops. | |
16 | * | |
17 | * There are a few funny things going on here. | |
18 | * | |
19 | * The page->private field is used to reference a struct | |
20 | * ceph_snap_context for _every_ dirty page. This indicates which | |
21 | * snapshot the page was logically dirtied in, and thus which snap | |
22 | * context needs to be associated with the osd write during writeback. | |
23 | * | |
24 | * Similarly, struct ceph_inode_info maintains a set of counters to | |
25 | * count dirty pages on the inode. In the absense of snapshots, | |
26 | * i_wrbuffer_ref == i_wrbuffer_ref_head == the dirty page count. | |
27 | * | |
28 | * When a snapshot is taken (that is, when the client receives | |
29 | * notification that a snapshot was taken), each inode with caps and | |
30 | * with dirty pages (dirty pages implies there is a cap) gets a new | |
31 | * ceph_cap_snap in the i_cap_snaps list (which is sorted in ascending | |
32 | * order, new snaps go to the tail). The i_wrbuffer_ref_head count is | |
33 | * moved to capsnap->dirty. (Unless a sync write is currently in | |
34 | * progress. In that case, the capsnap is said to be "pending", new | |
35 | * writes cannot start, and the capsnap isn't "finalized" until the | |
36 | * write completes (or fails) and a final size/mtime for the inode for | |
37 | * that snap can be settled upon.) i_wrbuffer_ref_head is reset to 0. | |
38 | * | |
39 | * On writeback, we must submit writes to the osd IN SNAP ORDER. So, | |
40 | * we look for the first capsnap in i_cap_snaps and write out pages in | |
41 | * that snap context _only_. Then we move on to the next capsnap, | |
42 | * eventually reaching the "live" or "head" context (i.e., pages that | |
43 | * are not yet snapped) and are writing the most recently dirtied | |
44 | * pages. | |
45 | * | |
46 | * Invalidate and so forth must take care to ensure the dirty page | |
47 | * accounting is preserved. | |
48 | */ | |
49 | ||
50 | ||
51 | /* | |
52 | * Dirty a page. Optimistically adjust accounting, on the assumption | |
53 | * that we won't race with invalidate. If we do, readjust. | |
54 | */ | |
55 | static int ceph_set_page_dirty(struct page *page) | |
56 | { | |
57 | struct address_space *mapping = page->mapping; | |
58 | struct inode *inode; | |
59 | struct ceph_inode_info *ci; | |
60 | int undo = 0; | |
61 | struct ceph_snap_context *snapc; | |
62 | ||
63 | if (unlikely(!mapping)) | |
64 | return !TestSetPageDirty(page); | |
65 | ||
66 | if (TestSetPageDirty(page)) { | |
67 | dout("%p set_page_dirty %p idx %lu -- already dirty\n", | |
68 | mapping->host, page, page->index); | |
69 | return 0; | |
70 | } | |
71 | ||
72 | inode = mapping->host; | |
73 | ci = ceph_inode(inode); | |
74 | ||
75 | /* | |
76 | * Note that we're grabbing a snapc ref here without holding | |
77 | * any locks! | |
78 | */ | |
79 | snapc = ceph_get_snap_context(ci->i_snap_realm->cached_context); | |
80 | ||
81 | /* dirty the head */ | |
82 | spin_lock(&inode->i_lock); | |
83 | if (ci->i_wrbuffer_ref_head == 0) | |
84 | ci->i_head_snapc = ceph_get_snap_context(snapc); | |
85 | ++ci->i_wrbuffer_ref_head; | |
86 | if (ci->i_wrbuffer_ref == 0) | |
87 | igrab(inode); | |
88 | ++ci->i_wrbuffer_ref; | |
89 | dout("%p set_page_dirty %p idx %lu head %d/%d -> %d/%d " | |
90 | "snapc %p seq %lld (%d snaps)\n", | |
91 | mapping->host, page, page->index, | |
92 | ci->i_wrbuffer_ref-1, ci->i_wrbuffer_ref_head-1, | |
93 | ci->i_wrbuffer_ref, ci->i_wrbuffer_ref_head, | |
94 | snapc, snapc->seq, snapc->num_snaps); | |
95 | spin_unlock(&inode->i_lock); | |
96 | ||
97 | /* now adjust page */ | |
98 | spin_lock_irq(&mapping->tree_lock); | |
99 | if (page->mapping) { /* Race with truncate? */ | |
100 | WARN_ON_ONCE(!PageUptodate(page)); | |
101 | ||
102 | if (mapping_cap_account_dirty(mapping)) { | |
103 | __inc_zone_page_state(page, NR_FILE_DIRTY); | |
104 | __inc_bdi_stat(mapping->backing_dev_info, | |
105 | BDI_RECLAIMABLE); | |
106 | task_io_account_write(PAGE_CACHE_SIZE); | |
107 | } | |
108 | radix_tree_tag_set(&mapping->page_tree, | |
109 | page_index(page), PAGECACHE_TAG_DIRTY); | |
110 | ||
111 | /* | |
112 | * Reference snap context in page->private. Also set | |
113 | * PagePrivate so that we get invalidatepage callback. | |
114 | */ | |
115 | page->private = (unsigned long)snapc; | |
116 | SetPagePrivate(page); | |
117 | } else { | |
118 | dout("ANON set_page_dirty %p (raced truncate?)\n", page); | |
119 | undo = 1; | |
120 | } | |
121 | ||
122 | spin_unlock_irq(&mapping->tree_lock); | |
123 | ||
124 | if (undo) | |
125 | /* whoops, we failed to dirty the page */ | |
126 | ceph_put_wrbuffer_cap_refs(ci, 1, snapc); | |
127 | ||
128 | __mark_inode_dirty(mapping->host, I_DIRTY_PAGES); | |
129 | ||
130 | BUG_ON(!PageDirty(page)); | |
131 | return 1; | |
132 | } | |
133 | ||
134 | /* | |
135 | * If we are truncating the full page (i.e. offset == 0), adjust the | |
136 | * dirty page counters appropriately. Only called if there is private | |
137 | * data on the page. | |
138 | */ | |
139 | static void ceph_invalidatepage(struct page *page, unsigned long offset) | |
140 | { | |
141 | struct inode *inode = page->mapping->host; | |
142 | struct ceph_inode_info *ci; | |
143 | struct ceph_snap_context *snapc = (void *)page->private; | |
144 | ||
145 | BUG_ON(!PageLocked(page)); | |
146 | BUG_ON(!page->private); | |
147 | BUG_ON(!PagePrivate(page)); | |
148 | BUG_ON(!page->mapping); | |
149 | ||
150 | /* | |
151 | * We can get non-dirty pages here due to races between | |
152 | * set_page_dirty and truncate_complete_page; just spit out a | |
153 | * warning, in case we end up with accounting problems later. | |
154 | */ | |
155 | if (!PageDirty(page)) | |
156 | pr_err("%p invalidatepage %p page not dirty\n", inode, page); | |
157 | ||
158 | if (offset == 0) | |
159 | ClearPageChecked(page); | |
160 | ||
161 | ci = ceph_inode(inode); | |
162 | if (offset == 0) { | |
163 | dout("%p invalidatepage %p idx %lu full dirty page %lu\n", | |
164 | inode, page, page->index, offset); | |
165 | ceph_put_wrbuffer_cap_refs(ci, 1, snapc); | |
166 | ceph_put_snap_context(snapc); | |
167 | page->private = 0; | |
168 | ClearPagePrivate(page); | |
169 | } else { | |
170 | dout("%p invalidatepage %p idx %lu partial dirty page\n", | |
171 | inode, page, page->index); | |
172 | } | |
173 | } | |
174 | ||
175 | /* just a sanity check */ | |
176 | static int ceph_releasepage(struct page *page, gfp_t g) | |
177 | { | |
178 | struct inode *inode = page->mapping ? page->mapping->host : NULL; | |
179 | dout("%p releasepage %p idx %lu\n", inode, page, page->index); | |
180 | WARN_ON(PageDirty(page)); | |
181 | WARN_ON(page->private); | |
182 | WARN_ON(PagePrivate(page)); | |
183 | return 0; | |
184 | } | |
185 | ||
186 | /* | |
187 | * read a single page, without unlocking it. | |
188 | */ | |
189 | static int readpage_nounlock(struct file *filp, struct page *page) | |
190 | { | |
191 | struct inode *inode = filp->f_dentry->d_inode; | |
192 | struct ceph_inode_info *ci = ceph_inode(inode); | |
193 | struct ceph_osd_client *osdc = &ceph_inode_to_client(inode)->osdc; | |
194 | int err = 0; | |
195 | u64 len = PAGE_CACHE_SIZE; | |
196 | ||
197 | dout("readpage inode %p file %p page %p index %lu\n", | |
198 | inode, filp, page, page->index); | |
199 | err = ceph_osdc_readpages(osdc, ceph_vino(inode), &ci->i_layout, | |
200 | page->index << PAGE_CACHE_SHIFT, &len, | |
201 | ci->i_truncate_seq, ci->i_truncate_size, | |
202 | &page, 1); | |
203 | if (err == -ENOENT) | |
204 | err = 0; | |
205 | if (err < 0) { | |
206 | SetPageError(page); | |
207 | goto out; | |
208 | } else if (err < PAGE_CACHE_SIZE) { | |
209 | /* zero fill remainder of page */ | |
210 | zero_user_segment(page, err, PAGE_CACHE_SIZE); | |
211 | } | |
212 | SetPageUptodate(page); | |
213 | ||
214 | out: | |
215 | return err < 0 ? err : 0; | |
216 | } | |
217 | ||
218 | static int ceph_readpage(struct file *filp, struct page *page) | |
219 | { | |
220 | int r = readpage_nounlock(filp, page); | |
221 | unlock_page(page); | |
222 | return r; | |
223 | } | |
224 | ||
225 | /* | |
226 | * Build a vector of contiguous pages from the provided page list. | |
227 | */ | |
228 | static struct page **page_vector_from_list(struct list_head *page_list, | |
229 | unsigned *nr_pages) | |
230 | { | |
231 | struct page **pages; | |
232 | struct page *page; | |
233 | int next_index, contig_pages = 0; | |
234 | ||
235 | /* build page vector */ | |
236 | pages = kmalloc(sizeof(*pages) * *nr_pages, GFP_NOFS); | |
237 | if (!pages) | |
238 | return ERR_PTR(-ENOMEM); | |
239 | ||
240 | BUG_ON(list_empty(page_list)); | |
241 | next_index = list_entry(page_list->prev, struct page, lru)->index; | |
242 | list_for_each_entry_reverse(page, page_list, lru) { | |
243 | if (page->index == next_index) { | |
244 | dout("readpages page %d %p\n", contig_pages, page); | |
245 | pages[contig_pages] = page; | |
246 | contig_pages++; | |
247 | next_index++; | |
248 | } else { | |
249 | break; | |
250 | } | |
251 | } | |
252 | *nr_pages = contig_pages; | |
253 | return pages; | |
254 | } | |
255 | ||
256 | /* | |
257 | * Read multiple pages. Leave pages we don't read + unlock in page_list; | |
258 | * the caller (VM) cleans them up. | |
259 | */ | |
260 | static int ceph_readpages(struct file *file, struct address_space *mapping, | |
261 | struct list_head *page_list, unsigned nr_pages) | |
262 | { | |
263 | struct inode *inode = file->f_dentry->d_inode; | |
264 | struct ceph_inode_info *ci = ceph_inode(inode); | |
265 | struct ceph_osd_client *osdc = &ceph_inode_to_client(inode)->osdc; | |
266 | int rc = 0; | |
267 | struct page **pages; | |
268 | struct pagevec pvec; | |
269 | loff_t offset; | |
270 | u64 len; | |
271 | ||
272 | dout("readpages %p file %p nr_pages %d\n", | |
273 | inode, file, nr_pages); | |
274 | ||
275 | pages = page_vector_from_list(page_list, &nr_pages); | |
276 | if (IS_ERR(pages)) | |
277 | return PTR_ERR(pages); | |
278 | ||
279 | /* guess read extent */ | |
280 | offset = pages[0]->index << PAGE_CACHE_SHIFT; | |
281 | len = nr_pages << PAGE_CACHE_SHIFT; | |
282 | rc = ceph_osdc_readpages(osdc, ceph_vino(inode), &ci->i_layout, | |
283 | offset, &len, | |
284 | ci->i_truncate_seq, ci->i_truncate_size, | |
285 | pages, nr_pages); | |
286 | if (rc == -ENOENT) | |
287 | rc = 0; | |
288 | if (rc < 0) | |
289 | goto out; | |
290 | ||
291 | /* set uptodate and add to lru in pagevec-sized chunks */ | |
292 | pagevec_init(&pvec, 0); | |
293 | for (; !list_empty(page_list) && len > 0; | |
294 | rc -= PAGE_CACHE_SIZE, len -= PAGE_CACHE_SIZE) { | |
295 | struct page *page = | |
296 | list_entry(page_list->prev, struct page, lru); | |
297 | ||
298 | list_del(&page->lru); | |
299 | ||
300 | if (rc < (int)PAGE_CACHE_SIZE) { | |
301 | /* zero (remainder of) page */ | |
302 | int s = rc < 0 ? 0 : rc; | |
303 | zero_user_segment(page, s, PAGE_CACHE_SIZE); | |
304 | } | |
305 | ||
306 | if (add_to_page_cache(page, mapping, page->index, GFP_NOFS)) { | |
307 | page_cache_release(page); | |
308 | dout("readpages %p add_to_page_cache failed %p\n", | |
309 | inode, page); | |
310 | continue; | |
311 | } | |
312 | dout("readpages %p adding %p idx %lu\n", inode, page, | |
313 | page->index); | |
314 | flush_dcache_page(page); | |
315 | SetPageUptodate(page); | |
316 | unlock_page(page); | |
317 | if (pagevec_add(&pvec, page) == 0) | |
318 | pagevec_lru_add_file(&pvec); /* add to lru */ | |
319 | } | |
320 | pagevec_lru_add_file(&pvec); | |
321 | rc = 0; | |
322 | ||
323 | out: | |
324 | kfree(pages); | |
325 | return rc; | |
326 | } | |
327 | ||
328 | /* | |
329 | * Get ref for the oldest snapc for an inode with dirty data... that is, the | |
330 | * only snap context we are allowed to write back. | |
331 | * | |
332 | * Caller holds i_lock. | |
333 | */ | |
334 | static struct ceph_snap_context *__get_oldest_context(struct inode *inode, | |
335 | u64 *snap_size) | |
336 | { | |
337 | struct ceph_inode_info *ci = ceph_inode(inode); | |
338 | struct ceph_snap_context *snapc = NULL; | |
339 | struct ceph_cap_snap *capsnap = NULL; | |
340 | ||
341 | list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) { | |
342 | dout(" cap_snap %p snapc %p has %d dirty pages\n", capsnap, | |
343 | capsnap->context, capsnap->dirty_pages); | |
344 | if (capsnap->dirty_pages) { | |
345 | snapc = ceph_get_snap_context(capsnap->context); | |
346 | if (snap_size) | |
347 | *snap_size = capsnap->size; | |
348 | break; | |
349 | } | |
350 | } | |
351 | if (!snapc && ci->i_snap_realm) { | |
352 | snapc = ceph_get_snap_context(ci->i_snap_realm->cached_context); | |
353 | dout(" head snapc %p has %d dirty pages\n", | |
354 | snapc, ci->i_wrbuffer_ref_head); | |
355 | } | |
356 | return snapc; | |
357 | } | |
358 | ||
359 | static struct ceph_snap_context *get_oldest_context(struct inode *inode, | |
360 | u64 *snap_size) | |
361 | { | |
362 | struct ceph_snap_context *snapc = NULL; | |
363 | ||
364 | spin_lock(&inode->i_lock); | |
365 | snapc = __get_oldest_context(inode, snap_size); | |
366 | spin_unlock(&inode->i_lock); | |
367 | return snapc; | |
368 | } | |
369 | ||
370 | /* | |
371 | * Write a single page, but leave the page locked. | |
372 | * | |
373 | * If we get a write error, set the page error bit, but still adjust the | |
374 | * dirty page accounting (i.e., page is no longer dirty). | |
375 | */ | |
376 | static int writepage_nounlock(struct page *page, struct writeback_control *wbc) | |
377 | { | |
378 | struct inode *inode; | |
379 | struct ceph_inode_info *ci; | |
380 | struct ceph_osd_client *osdc; | |
381 | loff_t page_off = page->index << PAGE_CACHE_SHIFT; | |
382 | int len = PAGE_CACHE_SIZE; | |
383 | loff_t i_size; | |
384 | int err = 0; | |
385 | struct ceph_snap_context *snapc; | |
386 | u64 snap_size = 0; | |
387 | ||
388 | dout("writepage %p idx %lu\n", page, page->index); | |
389 | ||
390 | if (!page->mapping || !page->mapping->host) { | |
391 | dout("writepage %p - no mapping\n", page); | |
392 | return -EFAULT; | |
393 | } | |
394 | inode = page->mapping->host; | |
395 | ci = ceph_inode(inode); | |
396 | osdc = &ceph_inode_to_client(inode)->osdc; | |
397 | ||
398 | /* verify this is a writeable snap context */ | |
399 | snapc = (void *)page->private; | |
400 | if (snapc == NULL) { | |
401 | dout("writepage %p page %p not dirty?\n", inode, page); | |
402 | goto out; | |
403 | } | |
404 | if (snapc != get_oldest_context(inode, &snap_size)) { | |
405 | dout("writepage %p page %p snapc %p not writeable - noop\n", | |
406 | inode, page, (void *)page->private); | |
407 | /* we should only noop if called by kswapd */ | |
408 | WARN_ON((current->flags & PF_MEMALLOC) == 0); | |
409 | goto out; | |
410 | } | |
411 | ||
412 | /* is this a partial page at end of file? */ | |
413 | if (snap_size) | |
414 | i_size = snap_size; | |
415 | else | |
416 | i_size = i_size_read(inode); | |
417 | if (i_size < page_off + len) | |
418 | len = i_size - page_off; | |
419 | ||
420 | dout("writepage %p page %p index %lu on %llu~%u\n", | |
421 | inode, page, page->index, page_off, len); | |
422 | ||
423 | set_page_writeback(page); | |
424 | err = ceph_osdc_writepages(osdc, ceph_vino(inode), | |
425 | &ci->i_layout, snapc, | |
426 | page_off, len, | |
427 | ci->i_truncate_seq, ci->i_truncate_size, | |
428 | &inode->i_mtime, | |
429 | &page, 1, 0, 0, true); | |
430 | if (err < 0) { | |
431 | dout("writepage setting page/mapping error %d %p\n", err, page); | |
432 | SetPageError(page); | |
433 | mapping_set_error(&inode->i_data, err); | |
434 | if (wbc) | |
435 | wbc->pages_skipped++; | |
436 | } else { | |
437 | dout("writepage cleaned page %p\n", page); | |
438 | err = 0; /* vfs expects us to return 0 */ | |
439 | } | |
440 | page->private = 0; | |
441 | ClearPagePrivate(page); | |
442 | end_page_writeback(page); | |
443 | ceph_put_wrbuffer_cap_refs(ci, 1, snapc); | |
444 | ceph_put_snap_context(snapc); | |
445 | out: | |
446 | return err; | |
447 | } | |
448 | ||
449 | static int ceph_writepage(struct page *page, struct writeback_control *wbc) | |
450 | { | |
451 | int err = writepage_nounlock(page, wbc); | |
452 | unlock_page(page); | |
453 | return err; | |
454 | } | |
455 | ||
456 | ||
457 | /* | |
458 | * lame release_pages helper. release_pages() isn't exported to | |
459 | * modules. | |
460 | */ | |
461 | static void ceph_release_pages(struct page **pages, int num) | |
462 | { | |
463 | struct pagevec pvec; | |
464 | int i; | |
465 | ||
466 | pagevec_init(&pvec, 0); | |
467 | for (i = 0; i < num; i++) { | |
468 | if (pagevec_add(&pvec, pages[i]) == 0) | |
469 | pagevec_release(&pvec); | |
470 | } | |
471 | pagevec_release(&pvec); | |
472 | } | |
473 | ||
474 | ||
475 | /* | |
476 | * async writeback completion handler. | |
477 | * | |
478 | * If we get an error, set the mapping error bit, but not the individual | |
479 | * page error bits. | |
480 | */ | |
481 | static void writepages_finish(struct ceph_osd_request *req, | |
482 | struct ceph_msg *msg) | |
483 | { | |
484 | struct inode *inode = req->r_inode; | |
485 | struct ceph_osd_reply_head *replyhead; | |
486 | struct ceph_osd_op *op; | |
487 | struct ceph_inode_info *ci = ceph_inode(inode); | |
488 | unsigned wrote; | |
489 | loff_t offset = req->r_pages[0]->index << PAGE_CACHE_SHIFT; | |
490 | struct page *page; | |
491 | int i; | |
492 | struct ceph_snap_context *snapc = req->r_snapc; | |
493 | struct address_space *mapping = inode->i_mapping; | |
494 | struct writeback_control *wbc = req->r_wbc; | |
495 | __s32 rc = -EIO; | |
496 | u64 bytes = 0; | |
497 | ||
498 | /* parse reply */ | |
499 | replyhead = msg->front.iov_base; | |
500 | WARN_ON(le32_to_cpu(replyhead->num_ops) == 0); | |
501 | op = (void *)(replyhead + 1); | |
502 | rc = le32_to_cpu(replyhead->result); | |
503 | bytes = le64_to_cpu(op->extent.length); | |
504 | ||
505 | if (rc >= 0) { | |
506 | wrote = (bytes + (offset & ~PAGE_CACHE_MASK) + ~PAGE_CACHE_MASK) | |
507 | >> PAGE_CACHE_SHIFT; | |
508 | WARN_ON(wrote != req->r_num_pages); | |
509 | } else { | |
510 | wrote = 0; | |
511 | mapping_set_error(mapping, rc); | |
512 | } | |
513 | dout("writepages_finish %p rc %d bytes %llu wrote %d (pages)\n", | |
514 | inode, rc, bytes, wrote); | |
515 | ||
516 | /* clean all pages */ | |
517 | for (i = 0; i < req->r_num_pages; i++) { | |
518 | page = req->r_pages[i]; | |
519 | BUG_ON(!page); | |
520 | WARN_ON(!PageUptodate(page)); | |
521 | ||
522 | if (i >= wrote) { | |
523 | dout("inode %p skipping page %p\n", inode, page); | |
524 | wbc->pages_skipped++; | |
525 | } | |
526 | page->private = 0; | |
527 | ClearPagePrivate(page); | |
528 | ceph_put_snap_context(snapc); | |
529 | dout("unlocking %d %p\n", i, page); | |
530 | end_page_writeback(page); | |
531 | unlock_page(page); | |
532 | } | |
533 | dout("%p wrote+cleaned %d pages\n", inode, wrote); | |
534 | ceph_put_wrbuffer_cap_refs(ci, req->r_num_pages, snapc); | |
535 | ||
536 | ceph_release_pages(req->r_pages, req->r_num_pages); | |
537 | if (req->r_pages_from_pool) | |
538 | mempool_free(req->r_pages, | |
539 | ceph_client(inode->i_sb)->wb_pagevec_pool); | |
540 | else | |
541 | kfree(req->r_pages); | |
542 | ceph_osdc_put_request(req); | |
543 | } | |
544 | ||
545 | /* | |
546 | * allocate a page vec, either directly, or if necessary, via a the | |
547 | * mempool. we avoid the mempool if we can because req->r_num_pages | |
548 | * may be less than the maximum write size. | |
549 | */ | |
550 | static void alloc_page_vec(struct ceph_client *client, | |
551 | struct ceph_osd_request *req) | |
552 | { | |
553 | req->r_pages = kmalloc(sizeof(struct page *) * req->r_num_pages, | |
554 | GFP_NOFS); | |
555 | if (!req->r_pages) { | |
556 | req->r_pages = mempool_alloc(client->wb_pagevec_pool, GFP_NOFS); | |
557 | req->r_pages_from_pool = 1; | |
558 | WARN_ON(!req->r_pages); | |
559 | } | |
560 | } | |
561 | ||
562 | /* | |
563 | * initiate async writeback | |
564 | */ | |
565 | static int ceph_writepages_start(struct address_space *mapping, | |
566 | struct writeback_control *wbc) | |
567 | { | |
568 | struct inode *inode = mapping->host; | |
569 | struct backing_dev_info *bdi = mapping->backing_dev_info; | |
570 | struct ceph_inode_info *ci = ceph_inode(inode); | |
571 | struct ceph_client *client = ceph_inode_to_client(inode); | |
572 | pgoff_t index, start, end; | |
573 | int range_whole = 0; | |
574 | int should_loop = 1; | |
575 | pgoff_t max_pages = 0, max_pages_ever = 0; | |
576 | struct ceph_snap_context *snapc = NULL, *last_snapc = NULL; | |
577 | struct pagevec pvec; | |
578 | int done = 0; | |
579 | int rc = 0; | |
580 | unsigned wsize = 1 << inode->i_blkbits; | |
581 | struct ceph_osd_request *req = NULL; | |
582 | int do_sync; | |
583 | u64 snap_size = 0; | |
584 | ||
585 | /* | |
586 | * Include a 'sync' in the OSD request if this is a data | |
587 | * integrity write (e.g., O_SYNC write or fsync()), or if our | |
588 | * cap is being revoked. | |
589 | */ | |
590 | do_sync = wbc->sync_mode == WB_SYNC_ALL; | |
591 | if (ceph_caps_revoking(ci, CEPH_CAP_FILE_BUFFER)) | |
592 | do_sync = 1; | |
593 | dout("writepages_start %p dosync=%d (mode=%s)\n", | |
594 | inode, do_sync, | |
595 | wbc->sync_mode == WB_SYNC_NONE ? "NONE" : | |
596 | (wbc->sync_mode == WB_SYNC_ALL ? "ALL" : "HOLD")); | |
597 | ||
598 | client = ceph_inode_to_client(inode); | |
599 | if (client->mount_state == CEPH_MOUNT_SHUTDOWN) { | |
600 | pr_warning("writepage_start %p on forced umount\n", inode); | |
601 | return -EIO; /* we're in a forced umount, don't write! */ | |
602 | } | |
6b805185 SW |
603 | if (client->mount_args->wsize && client->mount_args->wsize < wsize) |
604 | wsize = client->mount_args->wsize; | |
1d3576fd SW |
605 | if (wsize < PAGE_CACHE_SIZE) |
606 | wsize = PAGE_CACHE_SIZE; | |
607 | max_pages_ever = wsize >> PAGE_CACHE_SHIFT; | |
608 | ||
609 | pagevec_init(&pvec, 0); | |
610 | ||
611 | /* ?? */ | |
612 | if (wbc->nonblocking && bdi_write_congested(bdi)) { | |
613 | dout(" writepages congested\n"); | |
614 | wbc->encountered_congestion = 1; | |
615 | goto out_final; | |
616 | } | |
617 | ||
618 | /* where to start/end? */ | |
619 | if (wbc->range_cyclic) { | |
620 | start = mapping->writeback_index; /* Start from prev offset */ | |
621 | end = -1; | |
622 | dout(" cyclic, start at %lu\n", start); | |
623 | } else { | |
624 | start = wbc->range_start >> PAGE_CACHE_SHIFT; | |
625 | end = wbc->range_end >> PAGE_CACHE_SHIFT; | |
626 | if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) | |
627 | range_whole = 1; | |
628 | should_loop = 0; | |
629 | dout(" not cyclic, %lu to %lu\n", start, end); | |
630 | } | |
631 | index = start; | |
632 | ||
633 | retry: | |
634 | /* find oldest snap context with dirty data */ | |
635 | ceph_put_snap_context(snapc); | |
636 | snapc = get_oldest_context(inode, &snap_size); | |
637 | if (!snapc) { | |
638 | /* hmm, why does writepages get called when there | |
639 | is no dirty data? */ | |
640 | dout(" no snap context with dirty data?\n"); | |
641 | goto out; | |
642 | } | |
643 | dout(" oldest snapc is %p seq %lld (%d snaps)\n", | |
644 | snapc, snapc->seq, snapc->num_snaps); | |
645 | if (last_snapc && snapc != last_snapc) { | |
646 | /* if we switched to a newer snapc, restart our scan at the | |
647 | * start of the original file range. */ | |
648 | dout(" snapc differs from last pass, restarting at %lu\n", | |
649 | index); | |
650 | index = start; | |
651 | } | |
652 | last_snapc = snapc; | |
653 | ||
654 | while (!done && index <= end) { | |
655 | unsigned i; | |
656 | int first; | |
657 | pgoff_t next; | |
658 | int pvec_pages, locked_pages; | |
659 | struct page *page; | |
660 | int want; | |
661 | u64 offset, len; | |
662 | struct ceph_osd_request_head *reqhead; | |
663 | struct ceph_osd_op *op; | |
664 | ||
665 | next = 0; | |
666 | locked_pages = 0; | |
667 | max_pages = max_pages_ever; | |
668 | ||
669 | get_more_pages: | |
670 | first = -1; | |
671 | want = min(end - index, | |
672 | min((pgoff_t)PAGEVEC_SIZE, | |
673 | max_pages - (pgoff_t)locked_pages) - 1) | |
674 | + 1; | |
675 | pvec_pages = pagevec_lookup_tag(&pvec, mapping, &index, | |
676 | PAGECACHE_TAG_DIRTY, | |
677 | want); | |
678 | dout("pagevec_lookup_tag got %d\n", pvec_pages); | |
679 | if (!pvec_pages && !locked_pages) | |
680 | break; | |
681 | for (i = 0; i < pvec_pages && locked_pages < max_pages; i++) { | |
682 | page = pvec.pages[i]; | |
683 | dout("? %p idx %lu\n", page, page->index); | |
684 | if (locked_pages == 0) | |
685 | lock_page(page); /* first page */ | |
686 | else if (!trylock_page(page)) | |
687 | break; | |
688 | ||
689 | /* only dirty pages, or our accounting breaks */ | |
690 | if (unlikely(!PageDirty(page)) || | |
691 | unlikely(page->mapping != mapping)) { | |
692 | dout("!dirty or !mapping %p\n", page); | |
693 | unlock_page(page); | |
694 | break; | |
695 | } | |
696 | if (!wbc->range_cyclic && page->index > end) { | |
697 | dout("end of range %p\n", page); | |
698 | done = 1; | |
699 | unlock_page(page); | |
700 | break; | |
701 | } | |
702 | if (next && (page->index != next)) { | |
703 | dout("not consecutive %p\n", page); | |
704 | unlock_page(page); | |
705 | break; | |
706 | } | |
707 | if (wbc->sync_mode != WB_SYNC_NONE) { | |
708 | dout("waiting on writeback %p\n", page); | |
709 | wait_on_page_writeback(page); | |
710 | } | |
711 | if ((snap_size && page_offset(page) > snap_size) || | |
712 | (!snap_size && | |
713 | page_offset(page) > i_size_read(inode))) { | |
714 | dout("%p page eof %llu\n", page, snap_size ? | |
715 | snap_size : i_size_read(inode)); | |
716 | done = 1; | |
717 | unlock_page(page); | |
718 | break; | |
719 | } | |
720 | if (PageWriteback(page)) { | |
721 | dout("%p under writeback\n", page); | |
722 | unlock_page(page); | |
723 | break; | |
724 | } | |
725 | ||
726 | /* only if matching snap context */ | |
727 | if (snapc != (void *)page->private) { | |
728 | dout("page snapc %p != oldest %p\n", | |
729 | (void *)page->private, snapc); | |
730 | unlock_page(page); | |
731 | if (!locked_pages) | |
732 | continue; /* keep looking for snap */ | |
733 | break; | |
734 | } | |
735 | ||
736 | if (!clear_page_dirty_for_io(page)) { | |
737 | dout("%p !clear_page_dirty_for_io\n", page); | |
738 | unlock_page(page); | |
739 | break; | |
740 | } | |
741 | ||
742 | /* ok */ | |
743 | if (locked_pages == 0) { | |
744 | /* prepare async write request */ | |
745 | offset = page->index << PAGE_CACHE_SHIFT; | |
746 | len = wsize; | |
747 | req = ceph_osdc_new_request(&client->osdc, | |
748 | &ci->i_layout, | |
749 | ceph_vino(inode), | |
750 | offset, &len, | |
751 | CEPH_OSD_OP_WRITE, | |
752 | CEPH_OSD_FLAG_WRITE | | |
753 | CEPH_OSD_FLAG_ONDISK, | |
754 | snapc, do_sync, | |
755 | ci->i_truncate_seq, | |
756 | ci->i_truncate_size, | |
757 | &inode->i_mtime, true, 1); | |
758 | max_pages = req->r_num_pages; | |
759 | ||
760 | alloc_page_vec(client, req); | |
761 | req->r_callback = writepages_finish; | |
762 | req->r_inode = inode; | |
763 | req->r_wbc = wbc; | |
764 | } | |
765 | ||
766 | /* note position of first page in pvec */ | |
767 | if (first < 0) | |
768 | first = i; | |
769 | dout("%p will write page %p idx %lu\n", | |
770 | inode, page, page->index); | |
771 | set_page_writeback(page); | |
772 | req->r_pages[locked_pages] = page; | |
773 | locked_pages++; | |
774 | next = page->index + 1; | |
775 | } | |
776 | ||
777 | /* did we get anything? */ | |
778 | if (!locked_pages) | |
779 | goto release_pvec_pages; | |
780 | if (i) { | |
781 | int j; | |
782 | BUG_ON(!locked_pages || first < 0); | |
783 | ||
784 | if (pvec_pages && i == pvec_pages && | |
785 | locked_pages < max_pages) { | |
786 | dout("reached end pvec, trying for more\n"); | |
787 | pagevec_reinit(&pvec); | |
788 | goto get_more_pages; | |
789 | } | |
790 | ||
791 | /* shift unused pages over in the pvec... we | |
792 | * will need to release them below. */ | |
793 | for (j = i; j < pvec_pages; j++) { | |
794 | dout(" pvec leftover page %p\n", | |
795 | pvec.pages[j]); | |
796 | pvec.pages[j-i+first] = pvec.pages[j]; | |
797 | } | |
798 | pvec.nr -= i-first; | |
799 | } | |
800 | ||
801 | /* submit the write */ | |
802 | offset = req->r_pages[0]->index << PAGE_CACHE_SHIFT; | |
803 | len = min((snap_size ? snap_size : i_size_read(inode)) - offset, | |
804 | (u64)locked_pages << PAGE_CACHE_SHIFT); | |
805 | dout("writepages got %d pages at %llu~%llu\n", | |
806 | locked_pages, offset, len); | |
807 | ||
808 | /* revise final length, page count */ | |
809 | req->r_num_pages = locked_pages; | |
810 | reqhead = req->r_request->front.iov_base; | |
811 | op = (void *)(reqhead + 1); | |
812 | op->extent.length = cpu_to_le64(len); | |
813 | op->payload_len = cpu_to_le32(len); | |
814 | req->r_request->hdr.data_len = cpu_to_le32(len); | |
815 | ||
816 | ceph_osdc_start_request(&client->osdc, req, true); | |
817 | req = NULL; | |
818 | ||
819 | /* continue? */ | |
820 | index = next; | |
821 | wbc->nr_to_write -= locked_pages; | |
822 | if (wbc->nr_to_write <= 0) | |
823 | done = 1; | |
824 | ||
825 | release_pvec_pages: | |
826 | dout("pagevec_release on %d pages (%p)\n", (int)pvec.nr, | |
827 | pvec.nr ? pvec.pages[0] : NULL); | |
828 | pagevec_release(&pvec); | |
829 | ||
830 | if (locked_pages && !done) | |
831 | goto retry; | |
832 | } | |
833 | ||
834 | if (should_loop && !done) { | |
835 | /* more to do; loop back to beginning of file */ | |
836 | dout("writepages looping back to beginning of file\n"); | |
837 | should_loop = 0; | |
838 | index = 0; | |
839 | goto retry; | |
840 | } | |
841 | ||
842 | if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0)) | |
843 | mapping->writeback_index = index; | |
844 | ||
845 | out: | |
846 | if (req) | |
847 | ceph_osdc_put_request(req); | |
848 | if (rc > 0) | |
849 | rc = 0; /* vfs expects us to return 0 */ | |
850 | ceph_put_snap_context(snapc); | |
851 | dout("writepages done, rc = %d\n", rc); | |
852 | out_final: | |
853 | return rc; | |
854 | } | |
855 | ||
856 | ||
857 | ||
858 | /* | |
859 | * See if a given @snapc is either writeable, or already written. | |
860 | */ | |
861 | static int context_is_writeable_or_written(struct inode *inode, | |
862 | struct ceph_snap_context *snapc) | |
863 | { | |
864 | struct ceph_snap_context *oldest = get_oldest_context(inode, NULL); | |
865 | return !oldest || snapc->seq <= oldest->seq; | |
866 | } | |
867 | ||
868 | /* | |
869 | * We are only allowed to write into/dirty the page if the page is | |
870 | * clean, or already dirty within the same snap context. | |
871 | */ | |
872 | static int ceph_write_begin(struct file *file, struct address_space *mapping, | |
873 | loff_t pos, unsigned len, unsigned flags, | |
874 | struct page **pagep, void **fsdata) | |
875 | { | |
876 | struct inode *inode = file->f_dentry->d_inode; | |
877 | struct ceph_inode_info *ci = ceph_inode(inode); | |
878 | struct ceph_mds_client *mdsc = &ceph_inode_to_client(inode)->mdsc; | |
879 | struct page *page; | |
880 | pgoff_t index = pos >> PAGE_CACHE_SHIFT; | |
881 | loff_t page_off = pos & PAGE_CACHE_MASK; | |
882 | int pos_in_page = pos & ~PAGE_CACHE_MASK; | |
883 | int end_in_page = pos_in_page + len; | |
884 | loff_t i_size; | |
885 | struct ceph_snap_context *snapc; | |
886 | int r; | |
887 | ||
888 | /* get a page*/ | |
889 | retry: | |
890 | page = grab_cache_page_write_begin(mapping, index, 0); | |
891 | if (!page) | |
892 | return -ENOMEM; | |
893 | *pagep = page; | |
894 | ||
895 | dout("write_begin file %p inode %p page %p %d~%d\n", file, | |
896 | inode, page, (int)pos, (int)len); | |
897 | ||
898 | retry_locked: | |
899 | /* writepages currently holds page lock, but if we change that later, */ | |
900 | wait_on_page_writeback(page); | |
901 | ||
902 | /* check snap context */ | |
903 | BUG_ON(!ci->i_snap_realm); | |
904 | down_read(&mdsc->snap_rwsem); | |
905 | BUG_ON(!ci->i_snap_realm->cached_context); | |
906 | if (page->private && | |
907 | (void *)page->private != ci->i_snap_realm->cached_context) { | |
908 | /* | |
909 | * this page is already dirty in another (older) snap | |
910 | * context! is it writeable now? | |
911 | */ | |
912 | snapc = get_oldest_context(inode, NULL); | |
913 | up_read(&mdsc->snap_rwsem); | |
914 | ||
915 | if (snapc != (void *)page->private) { | |
916 | dout(" page %p snapc %p not current or oldest\n", | |
917 | page, (void *)page->private); | |
918 | /* | |
919 | * queue for writeback, and wait for snapc to | |
920 | * be writeable or written | |
921 | */ | |
922 | snapc = ceph_get_snap_context((void *)page->private); | |
923 | unlock_page(page); | |
924 | if (ceph_queue_writeback(inode)) | |
925 | igrab(inode); | |
926 | wait_event_interruptible(ci->i_cap_wq, | |
927 | context_is_writeable_or_written(inode, snapc)); | |
928 | ceph_put_snap_context(snapc); | |
929 | goto retry; | |
930 | } | |
931 | ||
932 | /* yay, writeable, do it now (without dropping page lock) */ | |
933 | dout(" page %p snapc %p not current, but oldest\n", | |
934 | page, snapc); | |
935 | if (!clear_page_dirty_for_io(page)) | |
936 | goto retry_locked; | |
937 | r = writepage_nounlock(page, NULL); | |
938 | if (r < 0) | |
939 | goto fail_nosnap; | |
940 | goto retry_locked; | |
941 | } | |
942 | ||
943 | if (PageUptodate(page)) { | |
944 | dout(" page %p already uptodate\n", page); | |
945 | return 0; | |
946 | } | |
947 | ||
948 | /* full page? */ | |
949 | if (pos_in_page == 0 && len == PAGE_CACHE_SIZE) | |
950 | return 0; | |
951 | ||
952 | /* past end of file? */ | |
953 | i_size = inode->i_size; /* caller holds i_mutex */ | |
954 | ||
955 | if (i_size + len > inode->i_sb->s_maxbytes) { | |
956 | /* file is too big */ | |
957 | r = -EINVAL; | |
958 | goto fail; | |
959 | } | |
960 | ||
961 | if (page_off >= i_size || | |
962 | (pos_in_page == 0 && (pos+len) >= i_size && | |
963 | end_in_page - pos_in_page != PAGE_CACHE_SIZE)) { | |
964 | dout(" zeroing %p 0 - %d and %d - %d\n", | |
965 | page, pos_in_page, end_in_page, (int)PAGE_CACHE_SIZE); | |
966 | zero_user_segments(page, | |
967 | 0, pos_in_page, | |
968 | end_in_page, PAGE_CACHE_SIZE); | |
969 | return 0; | |
970 | } | |
971 | ||
972 | /* we need to read it. */ | |
973 | up_read(&mdsc->snap_rwsem); | |
974 | r = readpage_nounlock(file, page); | |
975 | if (r < 0) | |
976 | goto fail_nosnap; | |
977 | goto retry_locked; | |
978 | ||
979 | fail: | |
980 | up_read(&mdsc->snap_rwsem); | |
981 | fail_nosnap: | |
982 | unlock_page(page); | |
983 | return r; | |
984 | } | |
985 | ||
986 | /* | |
987 | * we don't do anything in here that simple_write_end doesn't do | |
988 | * except adjust dirty page accounting and drop read lock on | |
989 | * mdsc->snap_rwsem. | |
990 | */ | |
991 | static int ceph_write_end(struct file *file, struct address_space *mapping, | |
992 | loff_t pos, unsigned len, unsigned copied, | |
993 | struct page *page, void *fsdata) | |
994 | { | |
995 | struct inode *inode = file->f_dentry->d_inode; | |
996 | struct ceph_mds_client *mdsc = &ceph_inode_to_client(inode)->mdsc; | |
997 | unsigned from = pos & (PAGE_CACHE_SIZE - 1); | |
998 | int check_cap = 0; | |
999 | ||
1000 | dout("write_end file %p inode %p page %p %d~%d (%d)\n", file, | |
1001 | inode, page, (int)pos, (int)copied, (int)len); | |
1002 | ||
1003 | /* zero the stale part of the page if we did a short copy */ | |
1004 | if (copied < len) | |
1005 | zero_user_segment(page, from+copied, len); | |
1006 | ||
1007 | /* did file size increase? */ | |
1008 | /* (no need for i_size_read(); we caller holds i_mutex */ | |
1009 | if (pos+copied > inode->i_size) | |
1010 | check_cap = ceph_inode_set_size(inode, pos+copied); | |
1011 | ||
1012 | if (!PageUptodate(page)) | |
1013 | SetPageUptodate(page); | |
1014 | ||
1015 | set_page_dirty(page); | |
1016 | ||
1017 | unlock_page(page); | |
1018 | up_read(&mdsc->snap_rwsem); | |
1019 | page_cache_release(page); | |
1020 | ||
1021 | if (check_cap) | |
1022 | ceph_check_caps(ceph_inode(inode), CHECK_CAPS_AUTHONLY, NULL); | |
1023 | ||
1024 | return copied; | |
1025 | } | |
1026 | ||
1027 | /* | |
1028 | * we set .direct_IO to indicate direct io is supported, but since we | |
1029 | * intercept O_DIRECT reads and writes early, this function should | |
1030 | * never get called. | |
1031 | */ | |
1032 | static ssize_t ceph_direct_io(int rw, struct kiocb *iocb, | |
1033 | const struct iovec *iov, | |
1034 | loff_t pos, unsigned long nr_segs) | |
1035 | { | |
1036 | WARN_ON(1); | |
1037 | return -EINVAL; | |
1038 | } | |
1039 | ||
1040 | const struct address_space_operations ceph_aops = { | |
1041 | .readpage = ceph_readpage, | |
1042 | .readpages = ceph_readpages, | |
1043 | .writepage = ceph_writepage, | |
1044 | .writepages = ceph_writepages_start, | |
1045 | .write_begin = ceph_write_begin, | |
1046 | .write_end = ceph_write_end, | |
1047 | .set_page_dirty = ceph_set_page_dirty, | |
1048 | .invalidatepage = ceph_invalidatepage, | |
1049 | .releasepage = ceph_releasepage, | |
1050 | .direct_IO = ceph_direct_io, | |
1051 | }; | |
1052 | ||
1053 | ||
1054 | /* | |
1055 | * vm ops | |
1056 | */ | |
1057 | ||
1058 | /* | |
1059 | * Reuse write_begin here for simplicity. | |
1060 | */ | |
1061 | static int ceph_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) | |
1062 | { | |
1063 | struct inode *inode = vma->vm_file->f_dentry->d_inode; | |
1064 | struct page *page = vmf->page; | |
1065 | struct ceph_mds_client *mdsc = &ceph_inode_to_client(inode)->mdsc; | |
1066 | loff_t off = page->index << PAGE_CACHE_SHIFT; | |
1067 | loff_t size, len; | |
1068 | struct page *locked_page = NULL; | |
1069 | void *fsdata = NULL; | |
1070 | int ret; | |
1071 | ||
1072 | size = i_size_read(inode); | |
1073 | if (off + PAGE_CACHE_SIZE <= size) | |
1074 | len = PAGE_CACHE_SIZE; | |
1075 | else | |
1076 | len = size & ~PAGE_CACHE_MASK; | |
1077 | ||
1078 | dout("page_mkwrite %p %llu~%llu page %p idx %lu\n", inode, | |
1079 | off, len, page, page->index); | |
1080 | ret = ceph_write_begin(vma->vm_file, inode->i_mapping, off, len, 0, | |
1081 | &locked_page, &fsdata); | |
1082 | WARN_ON(page != locked_page); | |
1083 | if (!ret) { | |
1084 | /* | |
1085 | * doing the following, instead of calling | |
1086 | * ceph_write_end. Note that we keep the | |
1087 | * page locked | |
1088 | */ | |
1089 | set_page_dirty(page); | |
1090 | up_read(&mdsc->snap_rwsem); | |
1091 | page_cache_release(page); | |
1092 | ret = VM_FAULT_LOCKED; | |
1093 | } else { | |
1094 | ret = VM_FAULT_SIGBUS; | |
1095 | } | |
1096 | dout("page_mkwrite %p %llu~%llu = %d\n", inode, off, len, ret); | |
1097 | return ret; | |
1098 | } | |
1099 | ||
1100 | static struct vm_operations_struct ceph_vmops = { | |
1101 | .fault = filemap_fault, | |
1102 | .page_mkwrite = ceph_page_mkwrite, | |
1103 | }; | |
1104 | ||
1105 | int ceph_mmap(struct file *file, struct vm_area_struct *vma) | |
1106 | { | |
1107 | struct address_space *mapping = file->f_mapping; | |
1108 | ||
1109 | if (!mapping->a_ops->readpage) | |
1110 | return -ENOEXEC; | |
1111 | file_accessed(file); | |
1112 | vma->vm_ops = &ceph_vmops; | |
1113 | vma->vm_flags |= VM_CAN_NONLINEAR; | |
1114 | return 0; | |
1115 | } |