xref: /linux/fs/ceph/addr.c (revision ec8a42e7343234802b9054874fe01810880289ce)
1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/ceph/ceph_debug.h>
3 
4 #include <linux/backing-dev.h>
5 #include <linux/fs.h>
6 #include <linux/mm.h>
7 #include <linux/pagemap.h>
8 #include <linux/writeback.h>	/* generic_writepages */
9 #include <linux/slab.h>
10 #include <linux/pagevec.h>
11 #include <linux/task_io_accounting_ops.h>
12 #include <linux/signal.h>
13 #include <linux/iversion.h>
14 #include <linux/ktime.h>
15 
16 #include "super.h"
17 #include "mds_client.h"
18 #include "cache.h"
19 #include "metric.h"
20 #include <linux/ceph/osd_client.h>
21 #include <linux/ceph/striper.h>
22 
23 /*
24  * Ceph address space ops.
25  *
26  * There are a few funny things going on here.
27  *
28  * The page->private field is used to reference a struct
29  * ceph_snap_context for _every_ dirty page.  This indicates which
30  * snapshot the page was logically dirtied in, and thus which snap
31  * context needs to be associated with the osd write during writeback.
32  *
33  * Similarly, struct ceph_inode_info maintains a set of counters to
34  * count dirty pages on the inode.  In the absence of snapshots,
35  * i_wrbuffer_ref == i_wrbuffer_ref_head == the dirty page count.
36  *
37  * When a snapshot is taken (that is, when the client receives
38  * notification that a snapshot was taken), each inode with caps and
39  * with dirty pages (dirty pages implies there is a cap) gets a new
40  * ceph_cap_snap in the i_cap_snaps list (which is sorted in ascending
41  * order, new snaps go to the tail).  The i_wrbuffer_ref_head count is
42  * moved to capsnap->dirty. (Unless a sync write is currently in
43  * progress.  In that case, the capsnap is said to be "pending", new
44  * writes cannot start, and the capsnap isn't "finalized" until the
45  * write completes (or fails) and a final size/mtime for the inode for
46  * that snap can be settled upon.)  i_wrbuffer_ref_head is reset to 0.
47  *
48  * On writeback, we must submit writes to the osd IN SNAP ORDER.  So,
49  * we look for the first capsnap in i_cap_snaps and write out pages in
50  * that snap context _only_.  Then we move on to the next capsnap,
51  * eventually reaching the "live" or "head" context (i.e., pages that
52  * are not yet snapped) and are writing the most recently dirtied
53  * pages.
54  *
55  * Invalidate and so forth must take care to ensure the dirty page
56  * accounting is preserved.
57  */
58 
59 #define CONGESTION_ON_THRESH(congestion_kb) (congestion_kb >> (PAGE_SHIFT-10))
60 #define CONGESTION_OFF_THRESH(congestion_kb)				\
61 	(CONGESTION_ON_THRESH(congestion_kb) -				\
62 	 (CONGESTION_ON_THRESH(congestion_kb) >> 2))
63 
64 static inline struct ceph_snap_context *page_snap_context(struct page *page)
65 {
66 	if (PagePrivate(page))
67 		return (void *)page->private;
68 	return NULL;
69 }
70 
71 /*
72  * Dirty a page.  Optimistically adjust accounting, on the assumption
73  * that we won't race with invalidate.  If we do, readjust.
74  */
75 static int ceph_set_page_dirty(struct page *page)
76 {
77 	struct address_space *mapping = page->mapping;
78 	struct inode *inode;
79 	struct ceph_inode_info *ci;
80 	struct ceph_snap_context *snapc;
81 	int ret;
82 
83 	if (unlikely(!mapping))
84 		return !TestSetPageDirty(page);
85 
86 	if (PageDirty(page)) {
87 		dout("%p set_page_dirty %p idx %lu -- already dirty\n",
88 		     mapping->host, page, page->index);
89 		BUG_ON(!PagePrivate(page));
90 		return 0;
91 	}
92 
93 	inode = mapping->host;
94 	ci = ceph_inode(inode);
95 
96 	/* dirty the head */
97 	spin_lock(&ci->i_ceph_lock);
98 	BUG_ON(ci->i_wr_ref == 0); // caller should hold Fw reference
99 	if (__ceph_have_pending_cap_snap(ci)) {
100 		struct ceph_cap_snap *capsnap =
101 				list_last_entry(&ci->i_cap_snaps,
102 						struct ceph_cap_snap,
103 						ci_item);
104 		snapc = ceph_get_snap_context(capsnap->context);
105 		capsnap->dirty_pages++;
106 	} else {
107 		BUG_ON(!ci->i_head_snapc);
108 		snapc = ceph_get_snap_context(ci->i_head_snapc);
109 		++ci->i_wrbuffer_ref_head;
110 	}
111 	if (ci->i_wrbuffer_ref == 0)
112 		ihold(inode);
113 	++ci->i_wrbuffer_ref;
114 	dout("%p set_page_dirty %p idx %lu head %d/%d -> %d/%d "
115 	     "snapc %p seq %lld (%d snaps)\n",
116 	     mapping->host, page, page->index,
117 	     ci->i_wrbuffer_ref-1, ci->i_wrbuffer_ref_head-1,
118 	     ci->i_wrbuffer_ref, ci->i_wrbuffer_ref_head,
119 	     snapc, snapc->seq, snapc->num_snaps);
120 	spin_unlock(&ci->i_ceph_lock);
121 
122 	/*
123 	 * Reference snap context in page->private.  Also set
124 	 * PagePrivate so that we get invalidatepage callback.
125 	 */
126 	BUG_ON(PagePrivate(page));
127 	page->private = (unsigned long)snapc;
128 	SetPagePrivate(page);
129 
130 	ret = __set_page_dirty_nobuffers(page);
131 	WARN_ON(!PageLocked(page));
132 	WARN_ON(!page->mapping);
133 
134 	return ret;
135 }
136 
137 /*
138  * If we are truncating the full page (i.e. offset == 0), adjust the
139  * dirty page counters appropriately.  Only called if there is private
140  * data on the page.
141  */
142 static void ceph_invalidatepage(struct page *page, unsigned int offset,
143 				unsigned int length)
144 {
145 	struct inode *inode;
146 	struct ceph_inode_info *ci;
147 	struct ceph_snap_context *snapc = page_snap_context(page);
148 
149 	inode = page->mapping->host;
150 	ci = ceph_inode(inode);
151 
152 	if (offset != 0 || length != PAGE_SIZE) {
153 		dout("%p invalidatepage %p idx %lu partial dirty page %u~%u\n",
154 		     inode, page, page->index, offset, length);
155 		return;
156 	}
157 
158 	ceph_invalidate_fscache_page(inode, page);
159 
160 	WARN_ON(!PageLocked(page));
161 	if (!PagePrivate(page))
162 		return;
163 
164 	dout("%p invalidatepage %p idx %lu full dirty page\n",
165 	     inode, page, page->index);
166 
167 	ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
168 	ceph_put_snap_context(snapc);
169 	page->private = 0;
170 	ClearPagePrivate(page);
171 }
172 
173 static int ceph_releasepage(struct page *page, gfp_t g)
174 {
175 	dout("%p releasepage %p idx %lu (%sdirty)\n", page->mapping->host,
176 	     page, page->index, PageDirty(page) ? "" : "not ");
177 
178 	/* Can we release the page from the cache? */
179 	if (!ceph_release_fscache_page(page, g))
180 		return 0;
181 
182 	return !PagePrivate(page);
183 }
184 
185 /* read a single page, without unlocking it. */
186 static int ceph_do_readpage(struct file *filp, struct page *page)
187 {
188 	struct inode *inode = file_inode(filp);
189 	struct ceph_inode_info *ci = ceph_inode(inode);
190 	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
191 	struct ceph_osd_client *osdc = &fsc->client->osdc;
192 	struct ceph_osd_request *req;
193 	struct ceph_vino vino = ceph_vino(inode);
194 	int err = 0;
195 	u64 off = page_offset(page);
196 	u64 len = PAGE_SIZE;
197 
198 	if (off >= i_size_read(inode)) {
199 		zero_user_segment(page, 0, PAGE_SIZE);
200 		SetPageUptodate(page);
201 		return 0;
202 	}
203 
204 	if (ci->i_inline_version != CEPH_INLINE_NONE) {
205 		/*
206 		 * Uptodate inline data should have been added
207 		 * into page cache while getting Fcr caps.
208 		 */
209 		if (off == 0)
210 			return -EINVAL;
211 		zero_user_segment(page, 0, PAGE_SIZE);
212 		SetPageUptodate(page);
213 		return 0;
214 	}
215 
216 	err = ceph_readpage_from_fscache(inode, page);
217 	if (err == 0)
218 		return -EINPROGRESS;
219 
220 	dout("readpage ino %llx.%llx file %p off %llu len %llu page %p index %lu\n",
221 	     vino.ino, vino.snap, filp, off, len, page, page->index);
222 	req = ceph_osdc_new_request(osdc, &ci->i_layout, vino, off, &len, 0, 1,
223 				    CEPH_OSD_OP_READ, CEPH_OSD_FLAG_READ, NULL,
224 				    ci->i_truncate_seq, ci->i_truncate_size,
225 				    false);
226 	if (IS_ERR(req))
227 		return PTR_ERR(req);
228 
229 	osd_req_op_extent_osd_data_pages(req, 0, &page, len, 0, false, false);
230 
231 	err = ceph_osdc_start_request(osdc, req, false);
232 	if (!err)
233 		err = ceph_osdc_wait_request(osdc, req);
234 
235 	ceph_update_read_latency(&fsc->mdsc->metric, req->r_start_latency,
236 				 req->r_end_latency, err);
237 
238 	ceph_osdc_put_request(req);
239 	dout("readpage result %d\n", err);
240 
241 	if (err == -ENOENT)
242 		err = 0;
243 	if (err < 0) {
244 		ceph_fscache_readpage_cancel(inode, page);
245 		if (err == -EBLOCKLISTED)
246 			fsc->blocklisted = true;
247 		goto out;
248 	}
249 	if (err < PAGE_SIZE)
250 		/* zero fill remainder of page */
251 		zero_user_segment(page, err, PAGE_SIZE);
252 	else
253 		flush_dcache_page(page);
254 
255 	SetPageUptodate(page);
256 	ceph_readpage_to_fscache(inode, page);
257 
258 out:
259 	return err < 0 ? err : 0;
260 }
261 
262 static int ceph_readpage(struct file *filp, struct page *page)
263 {
264 	int r = ceph_do_readpage(filp, page);
265 	if (r != -EINPROGRESS)
266 		unlock_page(page);
267 	else
268 		r = 0;
269 	return r;
270 }
271 
272 /*
273  * Finish an async read(ahead) op.
274  */
275 static void finish_read(struct ceph_osd_request *req)
276 {
277 	struct inode *inode = req->r_inode;
278 	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
279 	struct ceph_osd_data *osd_data;
280 	int rc = req->r_result <= 0 ? req->r_result : 0;
281 	int bytes = req->r_result >= 0 ? req->r_result : 0;
282 	int num_pages;
283 	int i;
284 
285 	dout("finish_read %p req %p rc %d bytes %d\n", inode, req, rc, bytes);
286 	if (rc == -EBLOCKLISTED)
287 		ceph_inode_to_client(inode)->blocklisted = true;
288 
289 	/* unlock all pages, zeroing any data we didn't read */
290 	osd_data = osd_req_op_extent_osd_data(req, 0);
291 	BUG_ON(osd_data->type != CEPH_OSD_DATA_TYPE_PAGES);
292 	num_pages = calc_pages_for((u64)osd_data->alignment,
293 					(u64)osd_data->length);
294 	for (i = 0; i < num_pages; i++) {
295 		struct page *page = osd_data->pages[i];
296 
297 		if (rc < 0 && rc != -ENOENT) {
298 			ceph_fscache_readpage_cancel(inode, page);
299 			goto unlock;
300 		}
301 		if (bytes < (int)PAGE_SIZE) {
302 			/* zero (remainder of) page */
303 			int s = bytes < 0 ? 0 : bytes;
304 			zero_user_segment(page, s, PAGE_SIZE);
305 		}
306  		dout("finish_read %p uptodate %p idx %lu\n", inode, page,
307 		     page->index);
308 		flush_dcache_page(page);
309 		SetPageUptodate(page);
310 		ceph_readpage_to_fscache(inode, page);
311 unlock:
312 		unlock_page(page);
313 		put_page(page);
314 		bytes -= PAGE_SIZE;
315 	}
316 
317 	ceph_update_read_latency(&fsc->mdsc->metric, req->r_start_latency,
318 				 req->r_end_latency, rc);
319 
320 	kfree(osd_data->pages);
321 }
322 
323 /*
324  * start an async read(ahead) operation.  return nr_pages we submitted
325  * a read for on success, or negative error code.
326  */
327 static int start_read(struct inode *inode, struct ceph_rw_context *rw_ctx,
328 		      struct list_head *page_list, int max)
329 {
330 	struct ceph_osd_client *osdc =
331 		&ceph_inode_to_client(inode)->client->osdc;
332 	struct ceph_inode_info *ci = ceph_inode(inode);
333 	struct page *page = lru_to_page(page_list);
334 	struct ceph_vino vino;
335 	struct ceph_osd_request *req;
336 	u64 off;
337 	u64 len;
338 	int i;
339 	struct page **pages;
340 	pgoff_t next_index;
341 	int nr_pages = 0;
342 	int got = 0;
343 	int ret = 0;
344 
345 	if (!rw_ctx) {
346 		/* caller of readpages does not hold buffer and read caps
347 		 * (fadvise, madvise and readahead cases) */
348 		int want = CEPH_CAP_FILE_CACHE;
349 		ret = ceph_try_get_caps(inode, CEPH_CAP_FILE_RD, want,
350 					true, &got);
351 		if (ret < 0) {
352 			dout("start_read %p, error getting cap\n", inode);
353 		} else if (!(got & want)) {
354 			dout("start_read %p, no cache cap\n", inode);
355 			ret = 0;
356 		}
357 		if (ret <= 0) {
358 			if (got)
359 				ceph_put_cap_refs(ci, got);
360 			while (!list_empty(page_list)) {
361 				page = lru_to_page(page_list);
362 				list_del(&page->lru);
363 				put_page(page);
364 			}
365 			return ret;
366 		}
367 	}
368 
369 	off = (u64) page_offset(page);
370 
371 	/* count pages */
372 	next_index = page->index;
373 	list_for_each_entry_reverse(page, page_list, lru) {
374 		if (page->index != next_index)
375 			break;
376 		nr_pages++;
377 		next_index++;
378 		if (max && nr_pages == max)
379 			break;
380 	}
381 	len = nr_pages << PAGE_SHIFT;
382 	dout("start_read %p nr_pages %d is %lld~%lld\n", inode, nr_pages,
383 	     off, len);
384 	vino = ceph_vino(inode);
385 	req = ceph_osdc_new_request(osdc, &ci->i_layout, vino, off, &len,
386 				    0, 1, CEPH_OSD_OP_READ,
387 				    CEPH_OSD_FLAG_READ, NULL,
388 				    ci->i_truncate_seq, ci->i_truncate_size,
389 				    false);
390 	if (IS_ERR(req)) {
391 		ret = PTR_ERR(req);
392 		goto out;
393 	}
394 
395 	/* build page vector */
396 	nr_pages = calc_pages_for(0, len);
397 	pages = kmalloc_array(nr_pages, sizeof(*pages), GFP_KERNEL);
398 	if (!pages) {
399 		ret = -ENOMEM;
400 		goto out_put;
401 	}
402 	for (i = 0; i < nr_pages; ++i) {
403 		page = list_entry(page_list->prev, struct page, lru);
404 		BUG_ON(PageLocked(page));
405 		list_del(&page->lru);
406 
407  		dout("start_read %p adding %p idx %lu\n", inode, page,
408 		     page->index);
409 		if (add_to_page_cache_lru(page, &inode->i_data, page->index,
410 					  GFP_KERNEL)) {
411 			ceph_fscache_uncache_page(inode, page);
412 			put_page(page);
413 			dout("start_read %p add_to_page_cache failed %p\n",
414 			     inode, page);
415 			nr_pages = i;
416 			if (nr_pages > 0) {
417 				len = nr_pages << PAGE_SHIFT;
418 				osd_req_op_extent_update(req, 0, len);
419 				break;
420 			}
421 			goto out_pages;
422 		}
423 		pages[i] = page;
424 	}
425 	osd_req_op_extent_osd_data_pages(req, 0, pages, len, 0, false, false);
426 	req->r_callback = finish_read;
427 	req->r_inode = inode;
428 
429 	dout("start_read %p starting %p %lld~%lld\n", inode, req, off, len);
430 	ret = ceph_osdc_start_request(osdc, req, false);
431 	if (ret < 0)
432 		goto out_pages;
433 	ceph_osdc_put_request(req);
434 
435 	/* After adding locked pages to page cache, the inode holds cache cap.
436 	 * So we can drop our cap refs. */
437 	if (got)
438 		ceph_put_cap_refs(ci, got);
439 
440 	return nr_pages;
441 
442 out_pages:
443 	for (i = 0; i < nr_pages; ++i) {
444 		ceph_fscache_readpage_cancel(inode, pages[i]);
445 		unlock_page(pages[i]);
446 	}
447 	ceph_put_page_vector(pages, nr_pages, false);
448 out_put:
449 	ceph_osdc_put_request(req);
450 out:
451 	if (got)
452 		ceph_put_cap_refs(ci, got);
453 	return ret;
454 }
455 
456 
457 /*
458  * Read multiple pages.  Leave pages we don't read + unlock in page_list;
459  * the caller (VM) cleans them up.
460  */
461 static int ceph_readpages(struct file *file, struct address_space *mapping,
462 			  struct list_head *page_list, unsigned nr_pages)
463 {
464 	struct inode *inode = file_inode(file);
465 	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
466 	struct ceph_file_info *fi = file->private_data;
467 	struct ceph_rw_context *rw_ctx;
468 	int rc = 0;
469 	int max = 0;
470 
471 	if (ceph_inode(inode)->i_inline_version != CEPH_INLINE_NONE)
472 		return -EINVAL;
473 
474 	rc = ceph_readpages_from_fscache(mapping->host, mapping, page_list,
475 					 &nr_pages);
476 
477 	if (rc == 0)
478 		goto out;
479 
480 	rw_ctx = ceph_find_rw_context(fi);
481 	max = fsc->mount_options->rsize >> PAGE_SHIFT;
482 	dout("readpages %p file %p ctx %p nr_pages %d max %d\n",
483 	     inode, file, rw_ctx, nr_pages, max);
484 	while (!list_empty(page_list)) {
485 		rc = start_read(inode, rw_ctx, page_list, max);
486 		if (rc < 0)
487 			goto out;
488 	}
489 out:
490 	ceph_fscache_readpages_cancel(inode, page_list);
491 
492 	dout("readpages %p file %p ret %d\n", inode, file, rc);
493 	return rc;
494 }
495 
496 struct ceph_writeback_ctl
497 {
498 	loff_t i_size;
499 	u64 truncate_size;
500 	u32 truncate_seq;
501 	bool size_stable;
502 	bool head_snapc;
503 };
504 
505 /*
506  * Get ref for the oldest snapc for an inode with dirty data... that is, the
507  * only snap context we are allowed to write back.
508  */
509 static struct ceph_snap_context *
510 get_oldest_context(struct inode *inode, struct ceph_writeback_ctl *ctl,
511 		   struct ceph_snap_context *page_snapc)
512 {
513 	struct ceph_inode_info *ci = ceph_inode(inode);
514 	struct ceph_snap_context *snapc = NULL;
515 	struct ceph_cap_snap *capsnap = NULL;
516 
517 	spin_lock(&ci->i_ceph_lock);
518 	list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) {
519 		dout(" cap_snap %p snapc %p has %d dirty pages\n", capsnap,
520 		     capsnap->context, capsnap->dirty_pages);
521 		if (!capsnap->dirty_pages)
522 			continue;
523 
524 		/* get i_size, truncate_{seq,size} for page_snapc? */
525 		if (snapc && capsnap->context != page_snapc)
526 			continue;
527 
528 		if (ctl) {
529 			if (capsnap->writing) {
530 				ctl->i_size = i_size_read(inode);
531 				ctl->size_stable = false;
532 			} else {
533 				ctl->i_size = capsnap->size;
534 				ctl->size_stable = true;
535 			}
536 			ctl->truncate_size = capsnap->truncate_size;
537 			ctl->truncate_seq = capsnap->truncate_seq;
538 			ctl->head_snapc = false;
539 		}
540 
541 		if (snapc)
542 			break;
543 
544 		snapc = ceph_get_snap_context(capsnap->context);
545 		if (!page_snapc ||
546 		    page_snapc == snapc ||
547 		    page_snapc->seq > snapc->seq)
548 			break;
549 	}
550 	if (!snapc && ci->i_wrbuffer_ref_head) {
551 		snapc = ceph_get_snap_context(ci->i_head_snapc);
552 		dout(" head snapc %p has %d dirty pages\n",
553 		     snapc, ci->i_wrbuffer_ref_head);
554 		if (ctl) {
555 			ctl->i_size = i_size_read(inode);
556 			ctl->truncate_size = ci->i_truncate_size;
557 			ctl->truncate_seq = ci->i_truncate_seq;
558 			ctl->size_stable = false;
559 			ctl->head_snapc = true;
560 		}
561 	}
562 	spin_unlock(&ci->i_ceph_lock);
563 	return snapc;
564 }
565 
566 static u64 get_writepages_data_length(struct inode *inode,
567 				      struct page *page, u64 start)
568 {
569 	struct ceph_inode_info *ci = ceph_inode(inode);
570 	struct ceph_snap_context *snapc = page_snap_context(page);
571 	struct ceph_cap_snap *capsnap = NULL;
572 	u64 end = i_size_read(inode);
573 
574 	if (snapc != ci->i_head_snapc) {
575 		bool found = false;
576 		spin_lock(&ci->i_ceph_lock);
577 		list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) {
578 			if (capsnap->context == snapc) {
579 				if (!capsnap->writing)
580 					end = capsnap->size;
581 				found = true;
582 				break;
583 			}
584 		}
585 		spin_unlock(&ci->i_ceph_lock);
586 		WARN_ON(!found);
587 	}
588 	if (end > page_offset(page) + PAGE_SIZE)
589 		end = page_offset(page) + PAGE_SIZE;
590 	return end > start ? end - start : 0;
591 }
592 
593 /*
594  * Write a single page, but leave the page locked.
595  *
596  * If we get a write error, mark the mapping for error, but still adjust the
597  * dirty page accounting (i.e., page is no longer dirty).
598  */
599 static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
600 {
601 	struct inode *inode = page->mapping->host;
602 	struct ceph_inode_info *ci = ceph_inode(inode);
603 	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
604 	struct ceph_snap_context *snapc, *oldest;
605 	loff_t page_off = page_offset(page);
606 	int err;
607 	loff_t len = PAGE_SIZE;
608 	struct ceph_writeback_ctl ceph_wbc;
609 	struct ceph_osd_client *osdc = &fsc->client->osdc;
610 	struct ceph_osd_request *req;
611 
612 	dout("writepage %p idx %lu\n", page, page->index);
613 
614 	/* verify this is a writeable snap context */
615 	snapc = page_snap_context(page);
616 	if (!snapc) {
617 		dout("writepage %p page %p not dirty?\n", inode, page);
618 		return 0;
619 	}
620 	oldest = get_oldest_context(inode, &ceph_wbc, snapc);
621 	if (snapc->seq > oldest->seq) {
622 		dout("writepage %p page %p snapc %p not writeable - noop\n",
623 		     inode, page, snapc);
624 		/* we should only noop if called by kswapd */
625 		WARN_ON(!(current->flags & PF_MEMALLOC));
626 		ceph_put_snap_context(oldest);
627 		redirty_page_for_writepage(wbc, page);
628 		return 0;
629 	}
630 	ceph_put_snap_context(oldest);
631 
632 	/* is this a partial page at end of file? */
633 	if (page_off >= ceph_wbc.i_size) {
634 		dout("%p page eof %llu\n", page, ceph_wbc.i_size);
635 		page->mapping->a_ops->invalidatepage(page, 0, PAGE_SIZE);
636 		return 0;
637 	}
638 
639 	if (ceph_wbc.i_size < page_off + len)
640 		len = ceph_wbc.i_size - page_off;
641 
642 	dout("writepage %p page %p index %lu on %llu~%llu snapc %p seq %lld\n",
643 	     inode, page, page->index, page_off, len, snapc, snapc->seq);
644 
645 	if (atomic_long_inc_return(&fsc->writeback_count) >
646 	    CONGESTION_ON_THRESH(fsc->mount_options->congestion_kb))
647 		set_bdi_congested(inode_to_bdi(inode), BLK_RW_ASYNC);
648 
649 	set_page_writeback(page);
650 	req = ceph_osdc_new_request(osdc, &ci->i_layout, ceph_vino(inode), page_off, &len, 0, 1,
651 				    CEPH_OSD_OP_WRITE, CEPH_OSD_FLAG_WRITE, snapc,
652 				    ceph_wbc.truncate_seq, ceph_wbc.truncate_size,
653 				    true);
654 	if (IS_ERR(req)) {
655 		redirty_page_for_writepage(wbc, page);
656 		end_page_writeback(page);
657 		return PTR_ERR(req);
658 	}
659 
660 	/* it may be a short write due to an object boundary */
661 	WARN_ON_ONCE(len > PAGE_SIZE);
662 	osd_req_op_extent_osd_data_pages(req, 0, &page, len, 0, false, false);
663 	dout("writepage %llu~%llu (%llu bytes)\n", page_off, len, len);
664 
665 	req->r_mtime = inode->i_mtime;
666 	err = ceph_osdc_start_request(osdc, req, true);
667 	if (!err)
668 		err = ceph_osdc_wait_request(osdc, req);
669 
670 	ceph_update_write_latency(&fsc->mdsc->metric, req->r_start_latency,
671 				  req->r_end_latency, err);
672 
673 	ceph_osdc_put_request(req);
674 	if (err == 0)
675 		err = len;
676 
677 	if (err < 0) {
678 		struct writeback_control tmp_wbc;
679 		if (!wbc)
680 			wbc = &tmp_wbc;
681 		if (err == -ERESTARTSYS) {
682 			/* killed by SIGKILL */
683 			dout("writepage interrupted page %p\n", page);
684 			redirty_page_for_writepage(wbc, page);
685 			end_page_writeback(page);
686 			return err;
687 		}
688 		if (err == -EBLOCKLISTED)
689 			fsc->blocklisted = true;
690 		dout("writepage setting page/mapping error %d %p\n",
691 		     err, page);
692 		mapping_set_error(&inode->i_data, err);
693 		wbc->pages_skipped++;
694 	} else {
695 		dout("writepage cleaned page %p\n", page);
696 		err = 0;  /* vfs expects us to return 0 */
697 	}
698 	page->private = 0;
699 	ClearPagePrivate(page);
700 	end_page_writeback(page);
701 	ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
702 	ceph_put_snap_context(snapc);  /* page's reference */
703 
704 	if (atomic_long_dec_return(&fsc->writeback_count) <
705 	    CONGESTION_OFF_THRESH(fsc->mount_options->congestion_kb))
706 		clear_bdi_congested(inode_to_bdi(inode), BLK_RW_ASYNC);
707 
708 	return err;
709 }
710 
711 static int ceph_writepage(struct page *page, struct writeback_control *wbc)
712 {
713 	int err;
714 	struct inode *inode = page->mapping->host;
715 	BUG_ON(!inode);
716 	ihold(inode);
717 	err = writepage_nounlock(page, wbc);
718 	if (err == -ERESTARTSYS) {
719 		/* direct memory reclaimer was killed by SIGKILL. return 0
720 		 * to prevent caller from setting mapping/page error */
721 		err = 0;
722 	}
723 	unlock_page(page);
724 	iput(inode);
725 	return err;
726 }
727 
728 /*
729  * async writeback completion handler.
730  *
731  * If we get an error, set the mapping error bit, but not the individual
732  * page error bits.
733  */
734 static void writepages_finish(struct ceph_osd_request *req)
735 {
736 	struct inode *inode = req->r_inode;
737 	struct ceph_inode_info *ci = ceph_inode(inode);
738 	struct ceph_osd_data *osd_data;
739 	struct page *page;
740 	int num_pages, total_pages = 0;
741 	int i, j;
742 	int rc = req->r_result;
743 	struct ceph_snap_context *snapc = req->r_snapc;
744 	struct address_space *mapping = inode->i_mapping;
745 	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
746 	bool remove_page;
747 
748 	dout("writepages_finish %p rc %d\n", inode, rc);
749 	if (rc < 0) {
750 		mapping_set_error(mapping, rc);
751 		ceph_set_error_write(ci);
752 		if (rc == -EBLOCKLISTED)
753 			fsc->blocklisted = true;
754 	} else {
755 		ceph_clear_error_write(ci);
756 	}
757 
758 	ceph_update_write_latency(&fsc->mdsc->metric, req->r_start_latency,
759 				  req->r_end_latency, rc);
760 
761 	/*
762 	 * We lost the cache cap, need to truncate the page before
763 	 * it is unlocked, otherwise we'd truncate it later in the
764 	 * page truncation thread, possibly losing some data that
765 	 * raced its way in
766 	 */
767 	remove_page = !(ceph_caps_issued(ci) &
768 			(CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO));
769 
770 	/* clean all pages */
771 	for (i = 0; i < req->r_num_ops; i++) {
772 		if (req->r_ops[i].op != CEPH_OSD_OP_WRITE)
773 			break;
774 
775 		osd_data = osd_req_op_extent_osd_data(req, i);
776 		BUG_ON(osd_data->type != CEPH_OSD_DATA_TYPE_PAGES);
777 		num_pages = calc_pages_for((u64)osd_data->alignment,
778 					   (u64)osd_data->length);
779 		total_pages += num_pages;
780 		for (j = 0; j < num_pages; j++) {
781 			page = osd_data->pages[j];
782 			BUG_ON(!page);
783 			WARN_ON(!PageUptodate(page));
784 
785 			if (atomic_long_dec_return(&fsc->writeback_count) <
786 			     CONGESTION_OFF_THRESH(
787 					fsc->mount_options->congestion_kb))
788 				clear_bdi_congested(inode_to_bdi(inode),
789 						    BLK_RW_ASYNC);
790 
791 			ceph_put_snap_context(page_snap_context(page));
792 			page->private = 0;
793 			ClearPagePrivate(page);
794 			dout("unlocking %p\n", page);
795 			end_page_writeback(page);
796 
797 			if (remove_page)
798 				generic_error_remove_page(inode->i_mapping,
799 							  page);
800 
801 			unlock_page(page);
802 		}
803 		dout("writepages_finish %p wrote %llu bytes cleaned %d pages\n",
804 		     inode, osd_data->length, rc >= 0 ? num_pages : 0);
805 
806 		release_pages(osd_data->pages, num_pages);
807 	}
808 
809 	ceph_put_wrbuffer_cap_refs(ci, total_pages, snapc);
810 
811 	osd_data = osd_req_op_extent_osd_data(req, 0);
812 	if (osd_data->pages_from_pool)
813 		mempool_free(osd_data->pages, ceph_wb_pagevec_pool);
814 	else
815 		kfree(osd_data->pages);
816 	ceph_osdc_put_request(req);
817 }
818 
819 /*
820  * initiate async writeback
821  */
822 static int ceph_writepages_start(struct address_space *mapping,
823 				 struct writeback_control *wbc)
824 {
825 	struct inode *inode = mapping->host;
826 	struct ceph_inode_info *ci = ceph_inode(inode);
827 	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
828 	struct ceph_vino vino = ceph_vino(inode);
829 	pgoff_t index, start_index, end = -1;
830 	struct ceph_snap_context *snapc = NULL, *last_snapc = NULL, *pgsnapc;
831 	struct pagevec pvec;
832 	int rc = 0;
833 	unsigned int wsize = i_blocksize(inode);
834 	struct ceph_osd_request *req = NULL;
835 	struct ceph_writeback_ctl ceph_wbc;
836 	bool should_loop, range_whole = false;
837 	bool done = false;
838 
839 	dout("writepages_start %p (mode=%s)\n", inode,
840 	     wbc->sync_mode == WB_SYNC_NONE ? "NONE" :
841 	     (wbc->sync_mode == WB_SYNC_ALL ? "ALL" : "HOLD"));
842 
843 	if (READ_ONCE(fsc->mount_state) >= CEPH_MOUNT_SHUTDOWN) {
844 		if (ci->i_wrbuffer_ref > 0) {
845 			pr_warn_ratelimited(
846 				"writepage_start %p %lld forced umount\n",
847 				inode, ceph_ino(inode));
848 		}
849 		mapping_set_error(mapping, -EIO);
850 		return -EIO; /* we're in a forced umount, don't write! */
851 	}
852 	if (fsc->mount_options->wsize < wsize)
853 		wsize = fsc->mount_options->wsize;
854 
855 	pagevec_init(&pvec);
856 
857 	start_index = wbc->range_cyclic ? mapping->writeback_index : 0;
858 	index = start_index;
859 
860 retry:
861 	/* find oldest snap context with dirty data */
862 	snapc = get_oldest_context(inode, &ceph_wbc, NULL);
863 	if (!snapc) {
864 		/* hmm, why does writepages get called when there
865 		   is no dirty data? */
866 		dout(" no snap context with dirty data?\n");
867 		goto out;
868 	}
869 	dout(" oldest snapc is %p seq %lld (%d snaps)\n",
870 	     snapc, snapc->seq, snapc->num_snaps);
871 
872 	should_loop = false;
873 	if (ceph_wbc.head_snapc && snapc != last_snapc) {
874 		/* where to start/end? */
875 		if (wbc->range_cyclic) {
876 			index = start_index;
877 			end = -1;
878 			if (index > 0)
879 				should_loop = true;
880 			dout(" cyclic, start at %lu\n", index);
881 		} else {
882 			index = wbc->range_start >> PAGE_SHIFT;
883 			end = wbc->range_end >> PAGE_SHIFT;
884 			if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
885 				range_whole = true;
886 			dout(" not cyclic, %lu to %lu\n", index, end);
887 		}
888 	} else if (!ceph_wbc.head_snapc) {
889 		/* Do not respect wbc->range_{start,end}. Dirty pages
890 		 * in that range can be associated with newer snapc.
891 		 * They are not writeable until we write all dirty pages
892 		 * associated with 'snapc' get written */
893 		if (index > 0)
894 			should_loop = true;
895 		dout(" non-head snapc, range whole\n");
896 	}
897 
898 	ceph_put_snap_context(last_snapc);
899 	last_snapc = snapc;
900 
901 	while (!done && index <= end) {
902 		int num_ops = 0, op_idx;
903 		unsigned i, pvec_pages, max_pages, locked_pages = 0;
904 		struct page **pages = NULL, **data_pages;
905 		struct page *page;
906 		pgoff_t strip_unit_end = 0;
907 		u64 offset = 0, len = 0;
908 		bool from_pool = false;
909 
910 		max_pages = wsize >> PAGE_SHIFT;
911 
912 get_more_pages:
913 		pvec_pages = pagevec_lookup_range_tag(&pvec, mapping, &index,
914 						end, PAGECACHE_TAG_DIRTY);
915 		dout("pagevec_lookup_range_tag got %d\n", pvec_pages);
916 		if (!pvec_pages && !locked_pages)
917 			break;
918 		for (i = 0; i < pvec_pages && locked_pages < max_pages; i++) {
919 			page = pvec.pages[i];
920 			dout("? %p idx %lu\n", page, page->index);
921 			if (locked_pages == 0)
922 				lock_page(page);  /* first page */
923 			else if (!trylock_page(page))
924 				break;
925 
926 			/* only dirty pages, or our accounting breaks */
927 			if (unlikely(!PageDirty(page)) ||
928 			    unlikely(page->mapping != mapping)) {
929 				dout("!dirty or !mapping %p\n", page);
930 				unlock_page(page);
931 				continue;
932 			}
933 			/* only if matching snap context */
934 			pgsnapc = page_snap_context(page);
935 			if (pgsnapc != snapc) {
936 				dout("page snapc %p %lld != oldest %p %lld\n",
937 				     pgsnapc, pgsnapc->seq, snapc, snapc->seq);
938 				if (!should_loop &&
939 				    !ceph_wbc.head_snapc &&
940 				    wbc->sync_mode != WB_SYNC_NONE)
941 					should_loop = true;
942 				unlock_page(page);
943 				continue;
944 			}
945 			if (page_offset(page) >= ceph_wbc.i_size) {
946 				dout("%p page eof %llu\n",
947 				     page, ceph_wbc.i_size);
948 				if ((ceph_wbc.size_stable ||
949 				    page_offset(page) >= i_size_read(inode)) &&
950 				    clear_page_dirty_for_io(page))
951 					mapping->a_ops->invalidatepage(page,
952 								0, PAGE_SIZE);
953 				unlock_page(page);
954 				continue;
955 			}
956 			if (strip_unit_end && (page->index > strip_unit_end)) {
957 				dout("end of strip unit %p\n", page);
958 				unlock_page(page);
959 				break;
960 			}
961 			if (PageWriteback(page)) {
962 				if (wbc->sync_mode == WB_SYNC_NONE) {
963 					dout("%p under writeback\n", page);
964 					unlock_page(page);
965 					continue;
966 				}
967 				dout("waiting on writeback %p\n", page);
968 				wait_on_page_writeback(page);
969 			}
970 
971 			if (!clear_page_dirty_for_io(page)) {
972 				dout("%p !clear_page_dirty_for_io\n", page);
973 				unlock_page(page);
974 				continue;
975 			}
976 
977 			/*
978 			 * We have something to write.  If this is
979 			 * the first locked page this time through,
980 			 * calculate max possinle write size and
981 			 * allocate a page array
982 			 */
983 			if (locked_pages == 0) {
984 				u64 objnum;
985 				u64 objoff;
986 				u32 xlen;
987 
988 				/* prepare async write request */
989 				offset = (u64)page_offset(page);
990 				ceph_calc_file_object_mapping(&ci->i_layout,
991 							      offset, wsize,
992 							      &objnum, &objoff,
993 							      &xlen);
994 				len = xlen;
995 
996 				num_ops = 1;
997 				strip_unit_end = page->index +
998 					((len - 1) >> PAGE_SHIFT);
999 
1000 				BUG_ON(pages);
1001 				max_pages = calc_pages_for(0, (u64)len);
1002 				pages = kmalloc_array(max_pages,
1003 						      sizeof(*pages),
1004 						      GFP_NOFS);
1005 				if (!pages) {
1006 					from_pool = true;
1007 					pages = mempool_alloc(ceph_wb_pagevec_pool, GFP_NOFS);
1008 					BUG_ON(!pages);
1009 				}
1010 
1011 				len = 0;
1012 			} else if (page->index !=
1013 				   (offset + len) >> PAGE_SHIFT) {
1014 				if (num_ops >= (from_pool ?  CEPH_OSD_SLAB_OPS :
1015 							     CEPH_OSD_MAX_OPS)) {
1016 					redirty_page_for_writepage(wbc, page);
1017 					unlock_page(page);
1018 					break;
1019 				}
1020 
1021 				num_ops++;
1022 				offset = (u64)page_offset(page);
1023 				len = 0;
1024 			}
1025 
1026 			/* note position of first page in pvec */
1027 			dout("%p will write page %p idx %lu\n",
1028 			     inode, page, page->index);
1029 
1030 			if (atomic_long_inc_return(&fsc->writeback_count) >
1031 			    CONGESTION_ON_THRESH(
1032 				    fsc->mount_options->congestion_kb)) {
1033 				set_bdi_congested(inode_to_bdi(inode),
1034 						  BLK_RW_ASYNC);
1035 			}
1036 
1037 
1038 			pages[locked_pages++] = page;
1039 			pvec.pages[i] = NULL;
1040 
1041 			len += PAGE_SIZE;
1042 		}
1043 
1044 		/* did we get anything? */
1045 		if (!locked_pages)
1046 			goto release_pvec_pages;
1047 		if (i) {
1048 			unsigned j, n = 0;
1049 			/* shift unused page to beginning of pvec */
1050 			for (j = 0; j < pvec_pages; j++) {
1051 				if (!pvec.pages[j])
1052 					continue;
1053 				if (n < j)
1054 					pvec.pages[n] = pvec.pages[j];
1055 				n++;
1056 			}
1057 			pvec.nr = n;
1058 
1059 			if (pvec_pages && i == pvec_pages &&
1060 			    locked_pages < max_pages) {
1061 				dout("reached end pvec, trying for more\n");
1062 				pagevec_release(&pvec);
1063 				goto get_more_pages;
1064 			}
1065 		}
1066 
1067 new_request:
1068 		offset = page_offset(pages[0]);
1069 		len = wsize;
1070 
1071 		req = ceph_osdc_new_request(&fsc->client->osdc,
1072 					&ci->i_layout, vino,
1073 					offset, &len, 0, num_ops,
1074 					CEPH_OSD_OP_WRITE, CEPH_OSD_FLAG_WRITE,
1075 					snapc, ceph_wbc.truncate_seq,
1076 					ceph_wbc.truncate_size, false);
1077 		if (IS_ERR(req)) {
1078 			req = ceph_osdc_new_request(&fsc->client->osdc,
1079 						&ci->i_layout, vino,
1080 						offset, &len, 0,
1081 						min(num_ops,
1082 						    CEPH_OSD_SLAB_OPS),
1083 						CEPH_OSD_OP_WRITE,
1084 						CEPH_OSD_FLAG_WRITE,
1085 						snapc, ceph_wbc.truncate_seq,
1086 						ceph_wbc.truncate_size, true);
1087 			BUG_ON(IS_ERR(req));
1088 		}
1089 		BUG_ON(len < page_offset(pages[locked_pages - 1]) +
1090 			     PAGE_SIZE - offset);
1091 
1092 		req->r_callback = writepages_finish;
1093 		req->r_inode = inode;
1094 
1095 		/* Format the osd request message and submit the write */
1096 		len = 0;
1097 		data_pages = pages;
1098 		op_idx = 0;
1099 		for (i = 0; i < locked_pages; i++) {
1100 			u64 cur_offset = page_offset(pages[i]);
1101 			if (offset + len != cur_offset) {
1102 				if (op_idx + 1 == req->r_num_ops)
1103 					break;
1104 				osd_req_op_extent_dup_last(req, op_idx,
1105 							   cur_offset - offset);
1106 				dout("writepages got pages at %llu~%llu\n",
1107 				     offset, len);
1108 				osd_req_op_extent_osd_data_pages(req, op_idx,
1109 							data_pages, len, 0,
1110 							from_pool, false);
1111 				osd_req_op_extent_update(req, op_idx, len);
1112 
1113 				len = 0;
1114 				offset = cur_offset;
1115 				data_pages = pages + i;
1116 				op_idx++;
1117 			}
1118 
1119 			set_page_writeback(pages[i]);
1120 			len += PAGE_SIZE;
1121 		}
1122 
1123 		if (ceph_wbc.size_stable) {
1124 			len = min(len, ceph_wbc.i_size - offset);
1125 		} else if (i == locked_pages) {
1126 			/* writepages_finish() clears writeback pages
1127 			 * according to the data length, so make sure
1128 			 * data length covers all locked pages */
1129 			u64 min_len = len + 1 - PAGE_SIZE;
1130 			len = get_writepages_data_length(inode, pages[i - 1],
1131 							 offset);
1132 			len = max(len, min_len);
1133 		}
1134 		dout("writepages got pages at %llu~%llu\n", offset, len);
1135 
1136 		osd_req_op_extent_osd_data_pages(req, op_idx, data_pages, len,
1137 						 0, from_pool, false);
1138 		osd_req_op_extent_update(req, op_idx, len);
1139 
1140 		BUG_ON(op_idx + 1 != req->r_num_ops);
1141 
1142 		from_pool = false;
1143 		if (i < locked_pages) {
1144 			BUG_ON(num_ops <= req->r_num_ops);
1145 			num_ops -= req->r_num_ops;
1146 			locked_pages -= i;
1147 
1148 			/* allocate new pages array for next request */
1149 			data_pages = pages;
1150 			pages = kmalloc_array(locked_pages, sizeof(*pages),
1151 					      GFP_NOFS);
1152 			if (!pages) {
1153 				from_pool = true;
1154 				pages = mempool_alloc(ceph_wb_pagevec_pool, GFP_NOFS);
1155 				BUG_ON(!pages);
1156 			}
1157 			memcpy(pages, data_pages + i,
1158 			       locked_pages * sizeof(*pages));
1159 			memset(data_pages + i, 0,
1160 			       locked_pages * sizeof(*pages));
1161 		} else {
1162 			BUG_ON(num_ops != req->r_num_ops);
1163 			index = pages[i - 1]->index + 1;
1164 			/* request message now owns the pages array */
1165 			pages = NULL;
1166 		}
1167 
1168 		req->r_mtime = inode->i_mtime;
1169 		rc = ceph_osdc_start_request(&fsc->client->osdc, req, true);
1170 		BUG_ON(rc);
1171 		req = NULL;
1172 
1173 		wbc->nr_to_write -= i;
1174 		if (pages)
1175 			goto new_request;
1176 
1177 		/*
1178 		 * We stop writing back only if we are not doing
1179 		 * integrity sync. In case of integrity sync we have to
1180 		 * keep going until we have written all the pages
1181 		 * we tagged for writeback prior to entering this loop.
1182 		 */
1183 		if (wbc->nr_to_write <= 0 && wbc->sync_mode == WB_SYNC_NONE)
1184 			done = true;
1185 
1186 release_pvec_pages:
1187 		dout("pagevec_release on %d pages (%p)\n", (int)pvec.nr,
1188 		     pvec.nr ? pvec.pages[0] : NULL);
1189 		pagevec_release(&pvec);
1190 	}
1191 
1192 	if (should_loop && !done) {
1193 		/* more to do; loop back to beginning of file */
1194 		dout("writepages looping back to beginning of file\n");
1195 		end = start_index - 1; /* OK even when start_index == 0 */
1196 
1197 		/* to write dirty pages associated with next snapc,
1198 		 * we need to wait until current writes complete */
1199 		if (wbc->sync_mode != WB_SYNC_NONE &&
1200 		    start_index == 0 && /* all dirty pages were checked */
1201 		    !ceph_wbc.head_snapc) {
1202 			struct page *page;
1203 			unsigned i, nr;
1204 			index = 0;
1205 			while ((index <= end) &&
1206 			       (nr = pagevec_lookup_tag(&pvec, mapping, &index,
1207 						PAGECACHE_TAG_WRITEBACK))) {
1208 				for (i = 0; i < nr; i++) {
1209 					page = pvec.pages[i];
1210 					if (page_snap_context(page) != snapc)
1211 						continue;
1212 					wait_on_page_writeback(page);
1213 				}
1214 				pagevec_release(&pvec);
1215 				cond_resched();
1216 			}
1217 		}
1218 
1219 		start_index = 0;
1220 		index = 0;
1221 		goto retry;
1222 	}
1223 
1224 	if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
1225 		mapping->writeback_index = index;
1226 
1227 out:
1228 	ceph_osdc_put_request(req);
1229 	ceph_put_snap_context(last_snapc);
1230 	dout("writepages dend - startone, rc = %d\n", rc);
1231 	return rc;
1232 }
1233 
1234 
1235 
1236 /*
1237  * See if a given @snapc is either writeable, or already written.
1238  */
1239 static int context_is_writeable_or_written(struct inode *inode,
1240 					   struct ceph_snap_context *snapc)
1241 {
1242 	struct ceph_snap_context *oldest = get_oldest_context(inode, NULL, NULL);
1243 	int ret = !oldest || snapc->seq <= oldest->seq;
1244 
1245 	ceph_put_snap_context(oldest);
1246 	return ret;
1247 }
1248 
1249 /**
1250  * ceph_find_incompatible - find an incompatible context and return it
1251  * @page: page being dirtied
1252  *
1253  * We are only allowed to write into/dirty a page if the page is
1254  * clean, or already dirty within the same snap context. Returns a
1255  * conflicting context if there is one, NULL if there isn't, or a
1256  * negative error code on other errors.
1257  *
1258  * Must be called with page lock held.
1259  */
1260 static struct ceph_snap_context *
1261 ceph_find_incompatible(struct page *page)
1262 {
1263 	struct inode *inode = page->mapping->host;
1264 	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
1265 	struct ceph_inode_info *ci = ceph_inode(inode);
1266 
1267 	if (READ_ONCE(fsc->mount_state) >= CEPH_MOUNT_SHUTDOWN) {
1268 		dout(" page %p forced umount\n", page);
1269 		return ERR_PTR(-EIO);
1270 	}
1271 
1272 	for (;;) {
1273 		struct ceph_snap_context *snapc, *oldest;
1274 
1275 		wait_on_page_writeback(page);
1276 
1277 		snapc = page_snap_context(page);
1278 		if (!snapc || snapc == ci->i_head_snapc)
1279 			break;
1280 
1281 		/*
1282 		 * this page is already dirty in another (older) snap
1283 		 * context!  is it writeable now?
1284 		 */
1285 		oldest = get_oldest_context(inode, NULL, NULL);
1286 		if (snapc->seq > oldest->seq) {
1287 			/* not writeable -- return it for the caller to deal with */
1288 			ceph_put_snap_context(oldest);
1289 			dout(" page %p snapc %p not current or oldest\n", page, snapc);
1290 			return ceph_get_snap_context(snapc);
1291 		}
1292 		ceph_put_snap_context(oldest);
1293 
1294 		/* yay, writeable, do it now (without dropping page lock) */
1295 		dout(" page %p snapc %p not current, but oldest\n", page, snapc);
1296 		if (clear_page_dirty_for_io(page)) {
1297 			int r = writepage_nounlock(page, NULL);
1298 			if (r < 0)
1299 				return ERR_PTR(r);
1300 		}
1301 	}
1302 	return NULL;
1303 }
1304 
1305 /*
1306  * We are only allowed to write into/dirty the page if the page is
1307  * clean, or already dirty within the same snap context.
1308  */
1309 static int ceph_write_begin(struct file *file, struct address_space *mapping,
1310 			    loff_t pos, unsigned len, unsigned flags,
1311 			    struct page **pagep, void **fsdata)
1312 {
1313 	struct inode *inode = file_inode(file);
1314 	struct ceph_inode_info *ci = ceph_inode(inode);
1315 	struct ceph_snap_context *snapc;
1316 	struct page *page = NULL;
1317 	pgoff_t index = pos >> PAGE_SHIFT;
1318 	int pos_in_page = pos & ~PAGE_MASK;
1319 	int r = 0;
1320 
1321 	dout("write_begin file %p inode %p page %p %d~%d\n", file, inode, page, (int)pos, (int)len);
1322 
1323 	for (;;) {
1324 		page = grab_cache_page_write_begin(mapping, index, flags);
1325 		if (!page) {
1326 			r = -ENOMEM;
1327 			break;
1328 		}
1329 
1330 		snapc = ceph_find_incompatible(page);
1331 		if (snapc) {
1332 			if (IS_ERR(snapc)) {
1333 				r = PTR_ERR(snapc);
1334 				break;
1335 			}
1336 			unlock_page(page);
1337 			put_page(page);
1338 			page = NULL;
1339 			ceph_queue_writeback(inode);
1340 			r = wait_event_killable(ci->i_cap_wq,
1341 						context_is_writeable_or_written(inode, snapc));
1342 			ceph_put_snap_context(snapc);
1343 			if (r != 0)
1344 				break;
1345 			continue;
1346 		}
1347 
1348 		if (PageUptodate(page)) {
1349 			dout(" page %p already uptodate\n", page);
1350 			break;
1351 		}
1352 
1353 		/*
1354 		 * In some cases we don't need to read at all:
1355 		 * - full page write
1356 		 * - write that lies completely beyond EOF
1357 		 * - write that covers the the page from start to EOF or beyond it
1358 		 */
1359 		if ((pos_in_page == 0 && len == PAGE_SIZE) ||
1360 		    (pos >= i_size_read(inode)) ||
1361 		    (pos_in_page == 0 && (pos + len) >= i_size_read(inode))) {
1362 			zero_user_segments(page, 0, pos_in_page,
1363 					   pos_in_page + len, PAGE_SIZE);
1364 			break;
1365 		}
1366 
1367 		/*
1368 		 * We need to read it. If we get back -EINPROGRESS, then the page was
1369 		 * handed off to fscache and it will be unlocked when the read completes.
1370 		 * Refind the page in that case so we can reacquire the page lock. Otherwise
1371 		 * we got a hard error or the read was completed synchronously.
1372 		 */
1373 		r = ceph_do_readpage(file, page);
1374 		if (r != -EINPROGRESS)
1375 			break;
1376 	}
1377 
1378 	if (r < 0) {
1379 		if (page) {
1380 			unlock_page(page);
1381 			put_page(page);
1382 		}
1383 	} else {
1384 		*pagep = page;
1385 	}
1386 	return r;
1387 }
1388 
1389 /*
1390  * we don't do anything in here that simple_write_end doesn't do
1391  * except adjust dirty page accounting
1392  */
1393 static int ceph_write_end(struct file *file, struct address_space *mapping,
1394 			  loff_t pos, unsigned len, unsigned copied,
1395 			  struct page *page, void *fsdata)
1396 {
1397 	struct inode *inode = file_inode(file);
1398 	bool check_cap = false;
1399 
1400 	dout("write_end file %p inode %p page %p %d~%d (%d)\n", file,
1401 	     inode, page, (int)pos, (int)copied, (int)len);
1402 
1403 	/* zero the stale part of the page if we did a short copy */
1404 	if (!PageUptodate(page)) {
1405 		if (copied < len) {
1406 			copied = 0;
1407 			goto out;
1408 		}
1409 		SetPageUptodate(page);
1410 	}
1411 
1412 	/* did file size increase? */
1413 	if (pos+copied > i_size_read(inode))
1414 		check_cap = ceph_inode_set_size(inode, pos+copied);
1415 
1416 	set_page_dirty(page);
1417 
1418 out:
1419 	unlock_page(page);
1420 	put_page(page);
1421 
1422 	if (check_cap)
1423 		ceph_check_caps(ceph_inode(inode), CHECK_CAPS_AUTHONLY, NULL);
1424 
1425 	return copied;
1426 }
1427 
1428 /*
1429  * we set .direct_IO to indicate direct io is supported, but since we
1430  * intercept O_DIRECT reads and writes early, this function should
1431  * never get called.
1432  */
1433 static ssize_t ceph_direct_io(struct kiocb *iocb, struct iov_iter *iter)
1434 {
1435 	WARN_ON(1);
1436 	return -EINVAL;
1437 }
1438 
1439 const struct address_space_operations ceph_aops = {
1440 	.readpage = ceph_readpage,
1441 	.readpages = ceph_readpages,
1442 	.writepage = ceph_writepage,
1443 	.writepages = ceph_writepages_start,
1444 	.write_begin = ceph_write_begin,
1445 	.write_end = ceph_write_end,
1446 	.set_page_dirty = ceph_set_page_dirty,
1447 	.invalidatepage = ceph_invalidatepage,
1448 	.releasepage = ceph_releasepage,
1449 	.direct_IO = ceph_direct_io,
1450 };
1451 
1452 static void ceph_block_sigs(sigset_t *oldset)
1453 {
1454 	sigset_t mask;
1455 	siginitsetinv(&mask, sigmask(SIGKILL));
1456 	sigprocmask(SIG_BLOCK, &mask, oldset);
1457 }
1458 
1459 static void ceph_restore_sigs(sigset_t *oldset)
1460 {
1461 	sigprocmask(SIG_SETMASK, oldset, NULL);
1462 }
1463 
1464 /*
1465  * vm ops
1466  */
1467 static vm_fault_t ceph_filemap_fault(struct vm_fault *vmf)
1468 {
1469 	struct vm_area_struct *vma = vmf->vma;
1470 	struct inode *inode = file_inode(vma->vm_file);
1471 	struct ceph_inode_info *ci = ceph_inode(inode);
1472 	struct ceph_file_info *fi = vma->vm_file->private_data;
1473 	struct page *pinned_page = NULL;
1474 	loff_t off = (loff_t)vmf->pgoff << PAGE_SHIFT;
1475 	int want, got, err;
1476 	sigset_t oldset;
1477 	vm_fault_t ret = VM_FAULT_SIGBUS;
1478 
1479 	ceph_block_sigs(&oldset);
1480 
1481 	dout("filemap_fault %p %llx.%llx %llu~%zd trying to get caps\n",
1482 	     inode, ceph_vinop(inode), off, (size_t)PAGE_SIZE);
1483 	if (fi->fmode & CEPH_FILE_MODE_LAZY)
1484 		want = CEPH_CAP_FILE_CACHE | CEPH_CAP_FILE_LAZYIO;
1485 	else
1486 		want = CEPH_CAP_FILE_CACHE;
1487 
1488 	got = 0;
1489 	err = ceph_get_caps(vma->vm_file, CEPH_CAP_FILE_RD, want, -1,
1490 			    &got, &pinned_page);
1491 	if (err < 0)
1492 		goto out_restore;
1493 
1494 	dout("filemap_fault %p %llu~%zd got cap refs on %s\n",
1495 	     inode, off, (size_t)PAGE_SIZE, ceph_cap_string(got));
1496 
1497 	if ((got & (CEPH_CAP_FILE_CACHE | CEPH_CAP_FILE_LAZYIO)) ||
1498 	    ci->i_inline_version == CEPH_INLINE_NONE) {
1499 		CEPH_DEFINE_RW_CONTEXT(rw_ctx, got);
1500 		ceph_add_rw_context(fi, &rw_ctx);
1501 		ret = filemap_fault(vmf);
1502 		ceph_del_rw_context(fi, &rw_ctx);
1503 		dout("filemap_fault %p %llu~%zd drop cap refs %s ret %x\n",
1504 			inode, off, (size_t)PAGE_SIZE,
1505 				ceph_cap_string(got), ret);
1506 	} else
1507 		err = -EAGAIN;
1508 
1509 	if (pinned_page)
1510 		put_page(pinned_page);
1511 	ceph_put_cap_refs(ci, got);
1512 
1513 	if (err != -EAGAIN)
1514 		goto out_restore;
1515 
1516 	/* read inline data */
1517 	if (off >= PAGE_SIZE) {
1518 		/* does not support inline data > PAGE_SIZE */
1519 		ret = VM_FAULT_SIGBUS;
1520 	} else {
1521 		struct address_space *mapping = inode->i_mapping;
1522 		struct page *page = find_or_create_page(mapping, 0,
1523 						mapping_gfp_constraint(mapping,
1524 						~__GFP_FS));
1525 		if (!page) {
1526 			ret = VM_FAULT_OOM;
1527 			goto out_inline;
1528 		}
1529 		err = __ceph_do_getattr(inode, page,
1530 					 CEPH_STAT_CAP_INLINE_DATA, true);
1531 		if (err < 0 || off >= i_size_read(inode)) {
1532 			unlock_page(page);
1533 			put_page(page);
1534 			ret = vmf_error(err);
1535 			goto out_inline;
1536 		}
1537 		if (err < PAGE_SIZE)
1538 			zero_user_segment(page, err, PAGE_SIZE);
1539 		else
1540 			flush_dcache_page(page);
1541 		SetPageUptodate(page);
1542 		vmf->page = page;
1543 		ret = VM_FAULT_MAJOR | VM_FAULT_LOCKED;
1544 out_inline:
1545 		dout("filemap_fault %p %llu~%zd read inline data ret %x\n",
1546 		     inode, off, (size_t)PAGE_SIZE, ret);
1547 	}
1548 out_restore:
1549 	ceph_restore_sigs(&oldset);
1550 	if (err < 0)
1551 		ret = vmf_error(err);
1552 
1553 	return ret;
1554 }
1555 
1556 /*
1557  * Reuse write_begin here for simplicity.
1558  */
1559 static vm_fault_t ceph_page_mkwrite(struct vm_fault *vmf)
1560 {
1561 	struct vm_area_struct *vma = vmf->vma;
1562 	struct inode *inode = file_inode(vma->vm_file);
1563 	struct ceph_inode_info *ci = ceph_inode(inode);
1564 	struct ceph_file_info *fi = vma->vm_file->private_data;
1565 	struct ceph_cap_flush *prealloc_cf;
1566 	struct page *page = vmf->page;
1567 	loff_t off = page_offset(page);
1568 	loff_t size = i_size_read(inode);
1569 	size_t len;
1570 	int want, got, err;
1571 	sigset_t oldset;
1572 	vm_fault_t ret = VM_FAULT_SIGBUS;
1573 
1574 	prealloc_cf = ceph_alloc_cap_flush();
1575 	if (!prealloc_cf)
1576 		return VM_FAULT_OOM;
1577 
1578 	sb_start_pagefault(inode->i_sb);
1579 	ceph_block_sigs(&oldset);
1580 
1581 	if (ci->i_inline_version != CEPH_INLINE_NONE) {
1582 		struct page *locked_page = NULL;
1583 		if (off == 0) {
1584 			lock_page(page);
1585 			locked_page = page;
1586 		}
1587 		err = ceph_uninline_data(vma->vm_file, locked_page);
1588 		if (locked_page)
1589 			unlock_page(locked_page);
1590 		if (err < 0)
1591 			goto out_free;
1592 	}
1593 
1594 	if (off + PAGE_SIZE <= size)
1595 		len = PAGE_SIZE;
1596 	else
1597 		len = size & ~PAGE_MASK;
1598 
1599 	dout("page_mkwrite %p %llx.%llx %llu~%zd getting caps i_size %llu\n",
1600 	     inode, ceph_vinop(inode), off, len, size);
1601 	if (fi->fmode & CEPH_FILE_MODE_LAZY)
1602 		want = CEPH_CAP_FILE_BUFFER | CEPH_CAP_FILE_LAZYIO;
1603 	else
1604 		want = CEPH_CAP_FILE_BUFFER;
1605 
1606 	got = 0;
1607 	err = ceph_get_caps(vma->vm_file, CEPH_CAP_FILE_WR, want, off + len,
1608 			    &got, NULL);
1609 	if (err < 0)
1610 		goto out_free;
1611 
1612 	dout("page_mkwrite %p %llu~%zd got cap refs on %s\n",
1613 	     inode, off, len, ceph_cap_string(got));
1614 
1615 	/* Update time before taking page lock */
1616 	file_update_time(vma->vm_file);
1617 	inode_inc_iversion_raw(inode);
1618 
1619 	do {
1620 		struct ceph_snap_context *snapc;
1621 
1622 		lock_page(page);
1623 
1624 		if (page_mkwrite_check_truncate(page, inode) < 0) {
1625 			unlock_page(page);
1626 			ret = VM_FAULT_NOPAGE;
1627 			break;
1628 		}
1629 
1630 		snapc = ceph_find_incompatible(page);
1631 		if (!snapc) {
1632 			/* success.  we'll keep the page locked. */
1633 			set_page_dirty(page);
1634 			ret = VM_FAULT_LOCKED;
1635 			break;
1636 		}
1637 
1638 		unlock_page(page);
1639 
1640 		if (IS_ERR(snapc)) {
1641 			ret = VM_FAULT_SIGBUS;
1642 			break;
1643 		}
1644 
1645 		ceph_queue_writeback(inode);
1646 		err = wait_event_killable(ci->i_cap_wq,
1647 				context_is_writeable_or_written(inode, snapc));
1648 		ceph_put_snap_context(snapc);
1649 	} while (err == 0);
1650 
1651 	if (ret == VM_FAULT_LOCKED ||
1652 	    ci->i_inline_version != CEPH_INLINE_NONE) {
1653 		int dirty;
1654 		spin_lock(&ci->i_ceph_lock);
1655 		ci->i_inline_version = CEPH_INLINE_NONE;
1656 		dirty = __ceph_mark_dirty_caps(ci, CEPH_CAP_FILE_WR,
1657 					       &prealloc_cf);
1658 		spin_unlock(&ci->i_ceph_lock);
1659 		if (dirty)
1660 			__mark_inode_dirty(inode, dirty);
1661 	}
1662 
1663 	dout("page_mkwrite %p %llu~%zd dropping cap refs on %s ret %x\n",
1664 	     inode, off, len, ceph_cap_string(got), ret);
1665 	ceph_put_cap_refs(ci, got);
1666 out_free:
1667 	ceph_restore_sigs(&oldset);
1668 	sb_end_pagefault(inode->i_sb);
1669 	ceph_free_cap_flush(prealloc_cf);
1670 	if (err < 0)
1671 		ret = vmf_error(err);
1672 	return ret;
1673 }
1674 
1675 void ceph_fill_inline_data(struct inode *inode, struct page *locked_page,
1676 			   char	*data, size_t len)
1677 {
1678 	struct address_space *mapping = inode->i_mapping;
1679 	struct page *page;
1680 
1681 	if (locked_page) {
1682 		page = locked_page;
1683 	} else {
1684 		if (i_size_read(inode) == 0)
1685 			return;
1686 		page = find_or_create_page(mapping, 0,
1687 					   mapping_gfp_constraint(mapping,
1688 					   ~__GFP_FS));
1689 		if (!page)
1690 			return;
1691 		if (PageUptodate(page)) {
1692 			unlock_page(page);
1693 			put_page(page);
1694 			return;
1695 		}
1696 	}
1697 
1698 	dout("fill_inline_data %p %llx.%llx len %zu locked_page %p\n",
1699 	     inode, ceph_vinop(inode), len, locked_page);
1700 
1701 	if (len > 0) {
1702 		void *kaddr = kmap_atomic(page);
1703 		memcpy(kaddr, data, len);
1704 		kunmap_atomic(kaddr);
1705 	}
1706 
1707 	if (page != locked_page) {
1708 		if (len < PAGE_SIZE)
1709 			zero_user_segment(page, len, PAGE_SIZE);
1710 		else
1711 			flush_dcache_page(page);
1712 
1713 		SetPageUptodate(page);
1714 		unlock_page(page);
1715 		put_page(page);
1716 	}
1717 }
1718 
1719 int ceph_uninline_data(struct file *filp, struct page *locked_page)
1720 {
1721 	struct inode *inode = file_inode(filp);
1722 	struct ceph_inode_info *ci = ceph_inode(inode);
1723 	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
1724 	struct ceph_osd_request *req;
1725 	struct page *page = NULL;
1726 	u64 len, inline_version;
1727 	int err = 0;
1728 	bool from_pagecache = false;
1729 
1730 	spin_lock(&ci->i_ceph_lock);
1731 	inline_version = ci->i_inline_version;
1732 	spin_unlock(&ci->i_ceph_lock);
1733 
1734 	dout("uninline_data %p %llx.%llx inline_version %llu\n",
1735 	     inode, ceph_vinop(inode), inline_version);
1736 
1737 	if (inline_version == 1 || /* initial version, no data */
1738 	    inline_version == CEPH_INLINE_NONE)
1739 		goto out;
1740 
1741 	if (locked_page) {
1742 		page = locked_page;
1743 		WARN_ON(!PageUptodate(page));
1744 	} else if (ceph_caps_issued(ci) &
1745 		   (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) {
1746 		page = find_get_page(inode->i_mapping, 0);
1747 		if (page) {
1748 			if (PageUptodate(page)) {
1749 				from_pagecache = true;
1750 				lock_page(page);
1751 			} else {
1752 				put_page(page);
1753 				page = NULL;
1754 			}
1755 		}
1756 	}
1757 
1758 	if (page) {
1759 		len = i_size_read(inode);
1760 		if (len > PAGE_SIZE)
1761 			len = PAGE_SIZE;
1762 	} else {
1763 		page = __page_cache_alloc(GFP_NOFS);
1764 		if (!page) {
1765 			err = -ENOMEM;
1766 			goto out;
1767 		}
1768 		err = __ceph_do_getattr(inode, page,
1769 					CEPH_STAT_CAP_INLINE_DATA, true);
1770 		if (err < 0) {
1771 			/* no inline data */
1772 			if (err == -ENODATA)
1773 				err = 0;
1774 			goto out;
1775 		}
1776 		len = err;
1777 	}
1778 
1779 	req = ceph_osdc_new_request(&fsc->client->osdc, &ci->i_layout,
1780 				    ceph_vino(inode), 0, &len, 0, 1,
1781 				    CEPH_OSD_OP_CREATE, CEPH_OSD_FLAG_WRITE,
1782 				    NULL, 0, 0, false);
1783 	if (IS_ERR(req)) {
1784 		err = PTR_ERR(req);
1785 		goto out;
1786 	}
1787 
1788 	req->r_mtime = inode->i_mtime;
1789 	err = ceph_osdc_start_request(&fsc->client->osdc, req, false);
1790 	if (!err)
1791 		err = ceph_osdc_wait_request(&fsc->client->osdc, req);
1792 	ceph_osdc_put_request(req);
1793 	if (err < 0)
1794 		goto out;
1795 
1796 	req = ceph_osdc_new_request(&fsc->client->osdc, &ci->i_layout,
1797 				    ceph_vino(inode), 0, &len, 1, 3,
1798 				    CEPH_OSD_OP_WRITE, CEPH_OSD_FLAG_WRITE,
1799 				    NULL, ci->i_truncate_seq,
1800 				    ci->i_truncate_size, false);
1801 	if (IS_ERR(req)) {
1802 		err = PTR_ERR(req);
1803 		goto out;
1804 	}
1805 
1806 	osd_req_op_extent_osd_data_pages(req, 1, &page, len, 0, false, false);
1807 
1808 	{
1809 		__le64 xattr_buf = cpu_to_le64(inline_version);
1810 		err = osd_req_op_xattr_init(req, 0, CEPH_OSD_OP_CMPXATTR,
1811 					    "inline_version", &xattr_buf,
1812 					    sizeof(xattr_buf),
1813 					    CEPH_OSD_CMPXATTR_OP_GT,
1814 					    CEPH_OSD_CMPXATTR_MODE_U64);
1815 		if (err)
1816 			goto out_put;
1817 	}
1818 
1819 	{
1820 		char xattr_buf[32];
1821 		int xattr_len = snprintf(xattr_buf, sizeof(xattr_buf),
1822 					 "%llu", inline_version);
1823 		err = osd_req_op_xattr_init(req, 2, CEPH_OSD_OP_SETXATTR,
1824 					    "inline_version",
1825 					    xattr_buf, xattr_len, 0, 0);
1826 		if (err)
1827 			goto out_put;
1828 	}
1829 
1830 	req->r_mtime = inode->i_mtime;
1831 	err = ceph_osdc_start_request(&fsc->client->osdc, req, false);
1832 	if (!err)
1833 		err = ceph_osdc_wait_request(&fsc->client->osdc, req);
1834 
1835 	ceph_update_write_latency(&fsc->mdsc->metric, req->r_start_latency,
1836 				  req->r_end_latency, err);
1837 
1838 out_put:
1839 	ceph_osdc_put_request(req);
1840 	if (err == -ECANCELED)
1841 		err = 0;
1842 out:
1843 	if (page && page != locked_page) {
1844 		if (from_pagecache) {
1845 			unlock_page(page);
1846 			put_page(page);
1847 		} else
1848 			__free_pages(page, 0);
1849 	}
1850 
1851 	dout("uninline_data %p %llx.%llx inline_version %llu = %d\n",
1852 	     inode, ceph_vinop(inode), inline_version, err);
1853 	return err;
1854 }
1855 
1856 static const struct vm_operations_struct ceph_vmops = {
1857 	.fault		= ceph_filemap_fault,
1858 	.page_mkwrite	= ceph_page_mkwrite,
1859 };
1860 
1861 int ceph_mmap(struct file *file, struct vm_area_struct *vma)
1862 {
1863 	struct address_space *mapping = file->f_mapping;
1864 
1865 	if (!mapping->a_ops->readpage)
1866 		return -ENOEXEC;
1867 	file_accessed(file);
1868 	vma->vm_ops = &ceph_vmops;
1869 	return 0;
1870 }
1871 
1872 enum {
1873 	POOL_READ	= 1,
1874 	POOL_WRITE	= 2,
1875 };
1876 
1877 static int __ceph_pool_perm_get(struct ceph_inode_info *ci,
1878 				s64 pool, struct ceph_string *pool_ns)
1879 {
1880 	struct ceph_fs_client *fsc = ceph_inode_to_client(&ci->vfs_inode);
1881 	struct ceph_mds_client *mdsc = fsc->mdsc;
1882 	struct ceph_osd_request *rd_req = NULL, *wr_req = NULL;
1883 	struct rb_node **p, *parent;
1884 	struct ceph_pool_perm *perm;
1885 	struct page **pages;
1886 	size_t pool_ns_len;
1887 	int err = 0, err2 = 0, have = 0;
1888 
1889 	down_read(&mdsc->pool_perm_rwsem);
1890 	p = &mdsc->pool_perm_tree.rb_node;
1891 	while (*p) {
1892 		perm = rb_entry(*p, struct ceph_pool_perm, node);
1893 		if (pool < perm->pool)
1894 			p = &(*p)->rb_left;
1895 		else if (pool > perm->pool)
1896 			p = &(*p)->rb_right;
1897 		else {
1898 			int ret = ceph_compare_string(pool_ns,
1899 						perm->pool_ns,
1900 						perm->pool_ns_len);
1901 			if (ret < 0)
1902 				p = &(*p)->rb_left;
1903 			else if (ret > 0)
1904 				p = &(*p)->rb_right;
1905 			else {
1906 				have = perm->perm;
1907 				break;
1908 			}
1909 		}
1910 	}
1911 	up_read(&mdsc->pool_perm_rwsem);
1912 	if (*p)
1913 		goto out;
1914 
1915 	if (pool_ns)
1916 		dout("__ceph_pool_perm_get pool %lld ns %.*s no perm cached\n",
1917 		     pool, (int)pool_ns->len, pool_ns->str);
1918 	else
1919 		dout("__ceph_pool_perm_get pool %lld no perm cached\n", pool);
1920 
1921 	down_write(&mdsc->pool_perm_rwsem);
1922 	p = &mdsc->pool_perm_tree.rb_node;
1923 	parent = NULL;
1924 	while (*p) {
1925 		parent = *p;
1926 		perm = rb_entry(parent, struct ceph_pool_perm, node);
1927 		if (pool < perm->pool)
1928 			p = &(*p)->rb_left;
1929 		else if (pool > perm->pool)
1930 			p = &(*p)->rb_right;
1931 		else {
1932 			int ret = ceph_compare_string(pool_ns,
1933 						perm->pool_ns,
1934 						perm->pool_ns_len);
1935 			if (ret < 0)
1936 				p = &(*p)->rb_left;
1937 			else if (ret > 0)
1938 				p = &(*p)->rb_right;
1939 			else {
1940 				have = perm->perm;
1941 				break;
1942 			}
1943 		}
1944 	}
1945 	if (*p) {
1946 		up_write(&mdsc->pool_perm_rwsem);
1947 		goto out;
1948 	}
1949 
1950 	rd_req = ceph_osdc_alloc_request(&fsc->client->osdc, NULL,
1951 					 1, false, GFP_NOFS);
1952 	if (!rd_req) {
1953 		err = -ENOMEM;
1954 		goto out_unlock;
1955 	}
1956 
1957 	rd_req->r_flags = CEPH_OSD_FLAG_READ;
1958 	osd_req_op_init(rd_req, 0, CEPH_OSD_OP_STAT, 0);
1959 	rd_req->r_base_oloc.pool = pool;
1960 	if (pool_ns)
1961 		rd_req->r_base_oloc.pool_ns = ceph_get_string(pool_ns);
1962 	ceph_oid_printf(&rd_req->r_base_oid, "%llx.00000000", ci->i_vino.ino);
1963 
1964 	err = ceph_osdc_alloc_messages(rd_req, GFP_NOFS);
1965 	if (err)
1966 		goto out_unlock;
1967 
1968 	wr_req = ceph_osdc_alloc_request(&fsc->client->osdc, NULL,
1969 					 1, false, GFP_NOFS);
1970 	if (!wr_req) {
1971 		err = -ENOMEM;
1972 		goto out_unlock;
1973 	}
1974 
1975 	wr_req->r_flags = CEPH_OSD_FLAG_WRITE;
1976 	osd_req_op_init(wr_req, 0, CEPH_OSD_OP_CREATE, CEPH_OSD_OP_FLAG_EXCL);
1977 	ceph_oloc_copy(&wr_req->r_base_oloc, &rd_req->r_base_oloc);
1978 	ceph_oid_copy(&wr_req->r_base_oid, &rd_req->r_base_oid);
1979 
1980 	err = ceph_osdc_alloc_messages(wr_req, GFP_NOFS);
1981 	if (err)
1982 		goto out_unlock;
1983 
1984 	/* one page should be large enough for STAT data */
1985 	pages = ceph_alloc_page_vector(1, GFP_KERNEL);
1986 	if (IS_ERR(pages)) {
1987 		err = PTR_ERR(pages);
1988 		goto out_unlock;
1989 	}
1990 
1991 	osd_req_op_raw_data_in_pages(rd_req, 0, pages, PAGE_SIZE,
1992 				     0, false, true);
1993 	err = ceph_osdc_start_request(&fsc->client->osdc, rd_req, false);
1994 
1995 	wr_req->r_mtime = ci->vfs_inode.i_mtime;
1996 	err2 = ceph_osdc_start_request(&fsc->client->osdc, wr_req, false);
1997 
1998 	if (!err)
1999 		err = ceph_osdc_wait_request(&fsc->client->osdc, rd_req);
2000 	if (!err2)
2001 		err2 = ceph_osdc_wait_request(&fsc->client->osdc, wr_req);
2002 
2003 	if (err >= 0 || err == -ENOENT)
2004 		have |= POOL_READ;
2005 	else if (err != -EPERM) {
2006 		if (err == -EBLOCKLISTED)
2007 			fsc->blocklisted = true;
2008 		goto out_unlock;
2009 	}
2010 
2011 	if (err2 == 0 || err2 == -EEXIST)
2012 		have |= POOL_WRITE;
2013 	else if (err2 != -EPERM) {
2014 		if (err2 == -EBLOCKLISTED)
2015 			fsc->blocklisted = true;
2016 		err = err2;
2017 		goto out_unlock;
2018 	}
2019 
2020 	pool_ns_len = pool_ns ? pool_ns->len : 0;
2021 	perm = kmalloc(sizeof(*perm) + pool_ns_len + 1, GFP_NOFS);
2022 	if (!perm) {
2023 		err = -ENOMEM;
2024 		goto out_unlock;
2025 	}
2026 
2027 	perm->pool = pool;
2028 	perm->perm = have;
2029 	perm->pool_ns_len = pool_ns_len;
2030 	if (pool_ns_len > 0)
2031 		memcpy(perm->pool_ns, pool_ns->str, pool_ns_len);
2032 	perm->pool_ns[pool_ns_len] = 0;
2033 
2034 	rb_link_node(&perm->node, parent, p);
2035 	rb_insert_color(&perm->node, &mdsc->pool_perm_tree);
2036 	err = 0;
2037 out_unlock:
2038 	up_write(&mdsc->pool_perm_rwsem);
2039 
2040 	ceph_osdc_put_request(rd_req);
2041 	ceph_osdc_put_request(wr_req);
2042 out:
2043 	if (!err)
2044 		err = have;
2045 	if (pool_ns)
2046 		dout("__ceph_pool_perm_get pool %lld ns %.*s result = %d\n",
2047 		     pool, (int)pool_ns->len, pool_ns->str, err);
2048 	else
2049 		dout("__ceph_pool_perm_get pool %lld result = %d\n", pool, err);
2050 	return err;
2051 }
2052 
2053 int ceph_pool_perm_check(struct inode *inode, int need)
2054 {
2055 	struct ceph_inode_info *ci = ceph_inode(inode);
2056 	struct ceph_string *pool_ns;
2057 	s64 pool;
2058 	int ret, flags;
2059 
2060 	if (ci->i_vino.snap != CEPH_NOSNAP) {
2061 		/*
2062 		 * Pool permission check needs to write to the first object.
2063 		 * But for snapshot, head of the first object may have alread
2064 		 * been deleted. Skip check to avoid creating orphan object.
2065 		 */
2066 		return 0;
2067 	}
2068 
2069 	if (ceph_test_mount_opt(ceph_inode_to_client(inode),
2070 				NOPOOLPERM))
2071 		return 0;
2072 
2073 	spin_lock(&ci->i_ceph_lock);
2074 	flags = ci->i_ceph_flags;
2075 	pool = ci->i_layout.pool_id;
2076 	spin_unlock(&ci->i_ceph_lock);
2077 check:
2078 	if (flags & CEPH_I_POOL_PERM) {
2079 		if ((need & CEPH_CAP_FILE_RD) && !(flags & CEPH_I_POOL_RD)) {
2080 			dout("ceph_pool_perm_check pool %lld no read perm\n",
2081 			     pool);
2082 			return -EPERM;
2083 		}
2084 		if ((need & CEPH_CAP_FILE_WR) && !(flags & CEPH_I_POOL_WR)) {
2085 			dout("ceph_pool_perm_check pool %lld no write perm\n",
2086 			     pool);
2087 			return -EPERM;
2088 		}
2089 		return 0;
2090 	}
2091 
2092 	pool_ns = ceph_try_get_string(ci->i_layout.pool_ns);
2093 	ret = __ceph_pool_perm_get(ci, pool, pool_ns);
2094 	ceph_put_string(pool_ns);
2095 	if (ret < 0)
2096 		return ret;
2097 
2098 	flags = CEPH_I_POOL_PERM;
2099 	if (ret & POOL_READ)
2100 		flags |= CEPH_I_POOL_RD;
2101 	if (ret & POOL_WRITE)
2102 		flags |= CEPH_I_POOL_WR;
2103 
2104 	spin_lock(&ci->i_ceph_lock);
2105 	if (pool == ci->i_layout.pool_id &&
2106 	    pool_ns == rcu_dereference_raw(ci->i_layout.pool_ns)) {
2107 		ci->i_ceph_flags |= flags;
2108         } else {
2109 		pool = ci->i_layout.pool_id;
2110 		flags = ci->i_ceph_flags;
2111 	}
2112 	spin_unlock(&ci->i_ceph_lock);
2113 	goto check;
2114 }
2115 
2116 void ceph_pool_perm_destroy(struct ceph_mds_client *mdsc)
2117 {
2118 	struct ceph_pool_perm *perm;
2119 	struct rb_node *n;
2120 
2121 	while (!RB_EMPTY_ROOT(&mdsc->pool_perm_tree)) {
2122 		n = rb_first(&mdsc->pool_perm_tree);
2123 		perm = rb_entry(n, struct ceph_pool_perm, node);
2124 		rb_erase(n, &mdsc->pool_perm_tree);
2125 		kfree(perm);
2126 	}
2127 }
2128