1 #include <linux/ceph/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/slab.h> 9 #include <linux/pagevec.h> 10 #include <linux/task_io_accounting_ops.h> 11 12 #include "super.h" 13 #include "mds_client.h" 14 #include <linux/ceph/osd_client.h> 15 16 /* 17 * Ceph address space ops. 18 * 19 * There are a few funny things going on here. 20 * 21 * The page->private field is used to reference a struct 22 * ceph_snap_context for _every_ dirty page. This indicates which 23 * snapshot the page was logically dirtied in, and thus which snap 24 * context needs to be associated with the osd write during writeback. 25 * 26 * Similarly, struct ceph_inode_info maintains a set of counters to 27 * count dirty pages on the inode. In the absence of snapshots, 28 * i_wrbuffer_ref == i_wrbuffer_ref_head == the dirty page count. 29 * 30 * When a snapshot is taken (that is, when the client receives 31 * notification that a snapshot was taken), each inode with caps and 32 * with dirty pages (dirty pages implies there is a cap) gets a new 33 * ceph_cap_snap in the i_cap_snaps list (which is sorted in ascending 34 * order, new snaps go to the tail). The i_wrbuffer_ref_head count is 35 * moved to capsnap->dirty. (Unless a sync write is currently in 36 * progress. In that case, the capsnap is said to be "pending", new 37 * writes cannot start, and the capsnap isn't "finalized" until the 38 * write completes (or fails) and a final size/mtime for the inode for 39 * that snap can be settled upon.) i_wrbuffer_ref_head is reset to 0. 40 * 41 * On writeback, we must submit writes to the osd IN SNAP ORDER. So, 42 * we look for the first capsnap in i_cap_snaps and write out pages in 43 * that snap context _only_. Then we move on to the next capsnap, 44 * eventually reaching the "live" or "head" context (i.e., pages that 45 * are not yet snapped) and are writing the most recently dirtied 46 * pages. 47 * 48 * Invalidate and so forth must take care to ensure the dirty page 49 * accounting is preserved. 50 */ 51 52 #define CONGESTION_ON_THRESH(congestion_kb) (congestion_kb >> (PAGE_SHIFT-10)) 53 #define CONGESTION_OFF_THRESH(congestion_kb) \ 54 (CONGESTION_ON_THRESH(congestion_kb) - \ 55 (CONGESTION_ON_THRESH(congestion_kb) >> 2)) 56 57 58 59 /* 60 * Dirty a page. Optimistically adjust accounting, on the assumption 61 * that we won't race with invalidate. If we do, readjust. 62 */ 63 static int ceph_set_page_dirty(struct page *page) 64 { 65 struct address_space *mapping = page->mapping; 66 struct inode *inode; 67 struct ceph_inode_info *ci; 68 int undo = 0; 69 struct ceph_snap_context *snapc; 70 71 if (unlikely(!mapping)) 72 return !TestSetPageDirty(page); 73 74 if (TestSetPageDirty(page)) { 75 dout("%p set_page_dirty %p idx %lu -- already dirty\n", 76 mapping->host, page, page->index); 77 return 0; 78 } 79 80 inode = mapping->host; 81 ci = ceph_inode(inode); 82 83 /* 84 * Note that we're grabbing a snapc ref here without holding 85 * any locks! 86 */ 87 snapc = ceph_get_snap_context(ci->i_snap_realm->cached_context); 88 89 /* dirty the head */ 90 spin_lock(&inode->i_lock); 91 if (ci->i_head_snapc == NULL) 92 ci->i_head_snapc = ceph_get_snap_context(snapc); 93 ++ci->i_wrbuffer_ref_head; 94 if (ci->i_wrbuffer_ref == 0) 95 ihold(inode); 96 ++ci->i_wrbuffer_ref; 97 dout("%p set_page_dirty %p idx %lu head %d/%d -> %d/%d " 98 "snapc %p seq %lld (%d snaps)\n", 99 mapping->host, page, page->index, 100 ci->i_wrbuffer_ref-1, ci->i_wrbuffer_ref_head-1, 101 ci->i_wrbuffer_ref, ci->i_wrbuffer_ref_head, 102 snapc, snapc->seq, snapc->num_snaps); 103 spin_unlock(&inode->i_lock); 104 105 /* now adjust page */ 106 spin_lock_irq(&mapping->tree_lock); 107 if (page->mapping) { /* Race with truncate? */ 108 WARN_ON_ONCE(!PageUptodate(page)); 109 account_page_dirtied(page, page->mapping); 110 radix_tree_tag_set(&mapping->page_tree, 111 page_index(page), PAGECACHE_TAG_DIRTY); 112 113 /* 114 * Reference snap context in page->private. Also set 115 * PagePrivate so that we get invalidatepage callback. 116 */ 117 page->private = (unsigned long)snapc; 118 SetPagePrivate(page); 119 } else { 120 dout("ANON set_page_dirty %p (raced truncate?)\n", page); 121 undo = 1; 122 } 123 124 spin_unlock_irq(&mapping->tree_lock); 125 126 if (undo) 127 /* whoops, we failed to dirty the page */ 128 ceph_put_wrbuffer_cap_refs(ci, 1, snapc); 129 130 __mark_inode_dirty(mapping->host, I_DIRTY_PAGES); 131 132 BUG_ON(!PageDirty(page)); 133 return 1; 134 } 135 136 /* 137 * If we are truncating the full page (i.e. offset == 0), adjust the 138 * dirty page counters appropriately. Only called if there is private 139 * data on the page. 140 */ 141 static void ceph_invalidatepage(struct page *page, unsigned long offset) 142 { 143 struct inode *inode; 144 struct ceph_inode_info *ci; 145 struct ceph_snap_context *snapc = (void *)page->private; 146 147 BUG_ON(!PageLocked(page)); 148 BUG_ON(!page->private); 149 BUG_ON(!PagePrivate(page)); 150 BUG_ON(!page->mapping); 151 152 inode = page->mapping->host; 153 154 /* 155 * We can get non-dirty pages here due to races between 156 * set_page_dirty and truncate_complete_page; just spit out a 157 * warning, in case we end up with accounting problems later. 158 */ 159 if (!PageDirty(page)) 160 pr_err("%p invalidatepage %p page not dirty\n", inode, page); 161 162 if (offset == 0) 163 ClearPageChecked(page); 164 165 ci = ceph_inode(inode); 166 if (offset == 0) { 167 dout("%p invalidatepage %p idx %lu full dirty page %lu\n", 168 inode, page, page->index, offset); 169 ceph_put_wrbuffer_cap_refs(ci, 1, snapc); 170 ceph_put_snap_context(snapc); 171 page->private = 0; 172 ClearPagePrivate(page); 173 } else { 174 dout("%p invalidatepage %p idx %lu partial dirty page\n", 175 inode, page, page->index); 176 } 177 } 178 179 /* just a sanity check */ 180 static int ceph_releasepage(struct page *page, gfp_t g) 181 { 182 struct inode *inode = page->mapping ? page->mapping->host : NULL; 183 dout("%p releasepage %p idx %lu\n", inode, page, page->index); 184 WARN_ON(PageDirty(page)); 185 WARN_ON(page->private); 186 WARN_ON(PagePrivate(page)); 187 return 0; 188 } 189 190 /* 191 * read a single page, without unlocking it. 192 */ 193 static int readpage_nounlock(struct file *filp, struct page *page) 194 { 195 struct inode *inode = filp->f_dentry->d_inode; 196 struct ceph_inode_info *ci = ceph_inode(inode); 197 struct ceph_osd_client *osdc = 198 &ceph_inode_to_client(inode)->client->osdc; 199 int err = 0; 200 u64 len = PAGE_CACHE_SIZE; 201 202 dout("readpage inode %p file %p page %p index %lu\n", 203 inode, filp, page, page->index); 204 err = ceph_osdc_readpages(osdc, ceph_vino(inode), &ci->i_layout, 205 page->index << PAGE_CACHE_SHIFT, &len, 206 ci->i_truncate_seq, ci->i_truncate_size, 207 &page, 1, 0); 208 if (err == -ENOENT) 209 err = 0; 210 if (err < 0) { 211 SetPageError(page); 212 goto out; 213 } else if (err < PAGE_CACHE_SIZE) { 214 /* zero fill remainder of page */ 215 zero_user_segment(page, err, PAGE_CACHE_SIZE); 216 } 217 SetPageUptodate(page); 218 219 out: 220 return err < 0 ? err : 0; 221 } 222 223 static int ceph_readpage(struct file *filp, struct page *page) 224 { 225 int r = readpage_nounlock(filp, page); 226 unlock_page(page); 227 return r; 228 } 229 230 /* 231 * Finish an async read(ahead) op. 232 */ 233 static void finish_read(struct ceph_osd_request *req, struct ceph_msg *msg) 234 { 235 struct inode *inode = req->r_inode; 236 struct ceph_osd_reply_head *replyhead; 237 int rc, bytes; 238 int i; 239 240 /* parse reply */ 241 replyhead = msg->front.iov_base; 242 WARN_ON(le32_to_cpu(replyhead->num_ops) == 0); 243 rc = le32_to_cpu(replyhead->result); 244 bytes = le32_to_cpu(msg->hdr.data_len); 245 246 dout("finish_read %p req %p rc %d bytes %d\n", inode, req, rc, bytes); 247 248 /* unlock all pages, zeroing any data we didn't read */ 249 for (i = 0; i < req->r_num_pages; i++, bytes -= PAGE_CACHE_SIZE) { 250 struct page *page = req->r_pages[i]; 251 252 if (bytes < (int)PAGE_CACHE_SIZE) { 253 /* zero (remainder of) page */ 254 int s = bytes < 0 ? 0 : bytes; 255 zero_user_segment(page, s, PAGE_CACHE_SIZE); 256 } 257 dout("finish_read %p uptodate %p idx %lu\n", inode, page, 258 page->index); 259 flush_dcache_page(page); 260 SetPageUptodate(page); 261 unlock_page(page); 262 page_cache_release(page); 263 } 264 kfree(req->r_pages); 265 } 266 267 /* 268 * start an async read(ahead) operation. return nr_pages we submitted 269 * a read for on success, or negative error code. 270 */ 271 static int start_read(struct inode *inode, struct list_head *page_list, int max) 272 { 273 struct ceph_osd_client *osdc = 274 &ceph_inode_to_client(inode)->client->osdc; 275 struct ceph_inode_info *ci = ceph_inode(inode); 276 struct page *page = list_entry(page_list->prev, struct page, lru); 277 struct ceph_osd_request *req; 278 u64 off; 279 u64 len; 280 int i; 281 struct page **pages; 282 pgoff_t next_index; 283 int nr_pages = 0; 284 int ret; 285 286 off = page->index << PAGE_CACHE_SHIFT; 287 288 /* count pages */ 289 next_index = page->index; 290 list_for_each_entry_reverse(page, page_list, lru) { 291 if (page->index != next_index) 292 break; 293 nr_pages++; 294 next_index++; 295 if (max && nr_pages == max) 296 break; 297 } 298 len = nr_pages << PAGE_CACHE_SHIFT; 299 dout("start_read %p nr_pages %d is %lld~%lld\n", inode, nr_pages, 300 off, len); 301 302 req = ceph_osdc_new_request(osdc, &ci->i_layout, ceph_vino(inode), 303 off, &len, 304 CEPH_OSD_OP_READ, CEPH_OSD_FLAG_READ, 305 NULL, 0, 306 ci->i_truncate_seq, ci->i_truncate_size, 307 NULL, false, 1, 0); 308 if (!req) 309 return -ENOMEM; 310 311 /* build page vector */ 312 nr_pages = len >> PAGE_CACHE_SHIFT; 313 pages = kmalloc(sizeof(*pages) * nr_pages, GFP_NOFS); 314 ret = -ENOMEM; 315 if (!pages) 316 goto out; 317 for (i = 0; i < nr_pages; ++i) { 318 page = list_entry(page_list->prev, struct page, lru); 319 BUG_ON(PageLocked(page)); 320 list_del(&page->lru); 321 322 dout("start_read %p adding %p idx %lu\n", inode, page, 323 page->index); 324 if (add_to_page_cache_lru(page, &inode->i_data, page->index, 325 GFP_NOFS)) { 326 page_cache_release(page); 327 dout("start_read %p add_to_page_cache failed %p\n", 328 inode, page); 329 nr_pages = i; 330 goto out_pages; 331 } 332 pages[i] = page; 333 } 334 req->r_pages = pages; 335 req->r_num_pages = nr_pages; 336 req->r_callback = finish_read; 337 req->r_inode = inode; 338 339 dout("start_read %p starting %p %lld~%lld\n", inode, req, off, len); 340 ret = ceph_osdc_start_request(osdc, req, false); 341 if (ret < 0) 342 goto out_pages; 343 ceph_osdc_put_request(req); 344 return nr_pages; 345 346 out_pages: 347 ceph_release_page_vector(pages, nr_pages); 348 kfree(pages); 349 out: 350 ceph_osdc_put_request(req); 351 return ret; 352 } 353 354 355 /* 356 * Read multiple pages. Leave pages we don't read + unlock in page_list; 357 * the caller (VM) cleans them up. 358 */ 359 static int ceph_readpages(struct file *file, struct address_space *mapping, 360 struct list_head *page_list, unsigned nr_pages) 361 { 362 struct inode *inode = file->f_dentry->d_inode; 363 struct ceph_fs_client *fsc = ceph_inode_to_client(inode); 364 int rc = 0; 365 int max = 0; 366 367 if (fsc->mount_options->rsize >= PAGE_CACHE_SIZE) 368 max = (fsc->mount_options->rsize + PAGE_CACHE_SIZE - 1) 369 >> PAGE_SHIFT; 370 371 dout("readpages %p file %p nr_pages %d max %d\n", inode, file, nr_pages, 372 max); 373 while (!list_empty(page_list)) { 374 rc = start_read(inode, page_list, max); 375 if (rc < 0) 376 goto out; 377 BUG_ON(rc == 0); 378 } 379 out: 380 dout("readpages %p file %p ret %d\n", inode, file, rc); 381 return rc; 382 } 383 384 /* 385 * Get ref for the oldest snapc for an inode with dirty data... that is, the 386 * only snap context we are allowed to write back. 387 */ 388 static struct ceph_snap_context *get_oldest_context(struct inode *inode, 389 u64 *snap_size) 390 { 391 struct ceph_inode_info *ci = ceph_inode(inode); 392 struct ceph_snap_context *snapc = NULL; 393 struct ceph_cap_snap *capsnap = NULL; 394 395 spin_lock(&inode->i_lock); 396 list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) { 397 dout(" cap_snap %p snapc %p has %d dirty pages\n", capsnap, 398 capsnap->context, capsnap->dirty_pages); 399 if (capsnap->dirty_pages) { 400 snapc = ceph_get_snap_context(capsnap->context); 401 if (snap_size) 402 *snap_size = capsnap->size; 403 break; 404 } 405 } 406 if (!snapc && ci->i_wrbuffer_ref_head) { 407 snapc = ceph_get_snap_context(ci->i_head_snapc); 408 dout(" head snapc %p has %d dirty pages\n", 409 snapc, ci->i_wrbuffer_ref_head); 410 } 411 spin_unlock(&inode->i_lock); 412 return snapc; 413 } 414 415 /* 416 * Write a single page, but leave the page locked. 417 * 418 * If we get a write error, set the page error bit, but still adjust the 419 * dirty page accounting (i.e., page is no longer dirty). 420 */ 421 static int writepage_nounlock(struct page *page, struct writeback_control *wbc) 422 { 423 struct inode *inode; 424 struct ceph_inode_info *ci; 425 struct ceph_fs_client *fsc; 426 struct ceph_osd_client *osdc; 427 loff_t page_off = page->index << PAGE_CACHE_SHIFT; 428 int len = PAGE_CACHE_SIZE; 429 loff_t i_size; 430 int err = 0; 431 struct ceph_snap_context *snapc, *oldest; 432 u64 snap_size = 0; 433 long writeback_stat; 434 435 dout("writepage %p idx %lu\n", page, page->index); 436 437 if (!page->mapping || !page->mapping->host) { 438 dout("writepage %p - no mapping\n", page); 439 return -EFAULT; 440 } 441 inode = page->mapping->host; 442 ci = ceph_inode(inode); 443 fsc = ceph_inode_to_client(inode); 444 osdc = &fsc->client->osdc; 445 446 /* verify this is a writeable snap context */ 447 snapc = (void *)page->private; 448 if (snapc == NULL) { 449 dout("writepage %p page %p not dirty?\n", inode, page); 450 goto out; 451 } 452 oldest = get_oldest_context(inode, &snap_size); 453 if (snapc->seq > oldest->seq) { 454 dout("writepage %p page %p snapc %p not writeable - noop\n", 455 inode, page, (void *)page->private); 456 /* we should only noop if called by kswapd */ 457 WARN_ON((current->flags & PF_MEMALLOC) == 0); 458 ceph_put_snap_context(oldest); 459 goto out; 460 } 461 ceph_put_snap_context(oldest); 462 463 /* is this a partial page at end of file? */ 464 if (snap_size) 465 i_size = snap_size; 466 else 467 i_size = i_size_read(inode); 468 if (i_size < page_off + len) 469 len = i_size - page_off; 470 471 dout("writepage %p page %p index %lu on %llu~%u snapc %p\n", 472 inode, page, page->index, page_off, len, snapc); 473 474 writeback_stat = atomic_long_inc_return(&fsc->writeback_count); 475 if (writeback_stat > 476 CONGESTION_ON_THRESH(fsc->mount_options->congestion_kb)) 477 set_bdi_congested(&fsc->backing_dev_info, BLK_RW_ASYNC); 478 479 set_page_writeback(page); 480 err = ceph_osdc_writepages(osdc, ceph_vino(inode), 481 &ci->i_layout, snapc, 482 page_off, len, 483 ci->i_truncate_seq, ci->i_truncate_size, 484 &inode->i_mtime, 485 &page, 1, 0, 0, true); 486 if (err < 0) { 487 dout("writepage setting page/mapping error %d %p\n", err, page); 488 SetPageError(page); 489 mapping_set_error(&inode->i_data, err); 490 if (wbc) 491 wbc->pages_skipped++; 492 } else { 493 dout("writepage cleaned page %p\n", page); 494 err = 0; /* vfs expects us to return 0 */ 495 } 496 page->private = 0; 497 ClearPagePrivate(page); 498 end_page_writeback(page); 499 ceph_put_wrbuffer_cap_refs(ci, 1, snapc); 500 ceph_put_snap_context(snapc); /* page's reference */ 501 out: 502 return err; 503 } 504 505 static int ceph_writepage(struct page *page, struct writeback_control *wbc) 506 { 507 int err; 508 struct inode *inode = page->mapping->host; 509 BUG_ON(!inode); 510 ihold(inode); 511 err = writepage_nounlock(page, wbc); 512 unlock_page(page); 513 iput(inode); 514 return err; 515 } 516 517 518 /* 519 * lame release_pages helper. release_pages() isn't exported to 520 * modules. 521 */ 522 static void ceph_release_pages(struct page **pages, int num) 523 { 524 struct pagevec pvec; 525 int i; 526 527 pagevec_init(&pvec, 0); 528 for (i = 0; i < num; i++) { 529 if (pagevec_add(&pvec, pages[i]) == 0) 530 pagevec_release(&pvec); 531 } 532 pagevec_release(&pvec); 533 } 534 535 536 /* 537 * async writeback completion handler. 538 * 539 * If we get an error, set the mapping error bit, but not the individual 540 * page error bits. 541 */ 542 static void writepages_finish(struct ceph_osd_request *req, 543 struct ceph_msg *msg) 544 { 545 struct inode *inode = req->r_inode; 546 struct ceph_osd_reply_head *replyhead; 547 struct ceph_osd_op *op; 548 struct ceph_inode_info *ci = ceph_inode(inode); 549 unsigned wrote; 550 struct page *page; 551 int i; 552 struct ceph_snap_context *snapc = req->r_snapc; 553 struct address_space *mapping = inode->i_mapping; 554 __s32 rc = -EIO; 555 u64 bytes = 0; 556 struct ceph_fs_client *fsc = ceph_inode_to_client(inode); 557 long writeback_stat; 558 unsigned issued = ceph_caps_issued(ci); 559 560 /* parse reply */ 561 replyhead = msg->front.iov_base; 562 WARN_ON(le32_to_cpu(replyhead->num_ops) == 0); 563 op = (void *)(replyhead + 1); 564 rc = le32_to_cpu(replyhead->result); 565 bytes = le64_to_cpu(op->extent.length); 566 567 if (rc >= 0) { 568 /* 569 * Assume we wrote the pages we originally sent. The 570 * osd might reply with fewer pages if our writeback 571 * raced with a truncation and was adjusted at the osd, 572 * so don't believe the reply. 573 */ 574 wrote = req->r_num_pages; 575 } else { 576 wrote = 0; 577 mapping_set_error(mapping, rc); 578 } 579 dout("writepages_finish %p rc %d bytes %llu wrote %d (pages)\n", 580 inode, rc, bytes, wrote); 581 582 /* clean all pages */ 583 for (i = 0; i < req->r_num_pages; i++) { 584 page = req->r_pages[i]; 585 BUG_ON(!page); 586 WARN_ON(!PageUptodate(page)); 587 588 writeback_stat = 589 atomic_long_dec_return(&fsc->writeback_count); 590 if (writeback_stat < 591 CONGESTION_OFF_THRESH(fsc->mount_options->congestion_kb)) 592 clear_bdi_congested(&fsc->backing_dev_info, 593 BLK_RW_ASYNC); 594 595 ceph_put_snap_context((void *)page->private); 596 page->private = 0; 597 ClearPagePrivate(page); 598 dout("unlocking %d %p\n", i, page); 599 end_page_writeback(page); 600 601 /* 602 * We lost the cache cap, need to truncate the page before 603 * it is unlocked, otherwise we'd truncate it later in the 604 * page truncation thread, possibly losing some data that 605 * raced its way in 606 */ 607 if ((issued & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) == 0) 608 generic_error_remove_page(inode->i_mapping, page); 609 610 unlock_page(page); 611 } 612 dout("%p wrote+cleaned %d pages\n", inode, wrote); 613 ceph_put_wrbuffer_cap_refs(ci, req->r_num_pages, snapc); 614 615 ceph_release_pages(req->r_pages, req->r_num_pages); 616 if (req->r_pages_from_pool) 617 mempool_free(req->r_pages, 618 ceph_sb_to_client(inode->i_sb)->wb_pagevec_pool); 619 else 620 kfree(req->r_pages); 621 ceph_osdc_put_request(req); 622 } 623 624 /* 625 * allocate a page vec, either directly, or if necessary, via a the 626 * mempool. we avoid the mempool if we can because req->r_num_pages 627 * may be less than the maximum write size. 628 */ 629 static void alloc_page_vec(struct ceph_fs_client *fsc, 630 struct ceph_osd_request *req) 631 { 632 req->r_pages = kmalloc(sizeof(struct page *) * req->r_num_pages, 633 GFP_NOFS); 634 if (!req->r_pages) { 635 req->r_pages = mempool_alloc(fsc->wb_pagevec_pool, GFP_NOFS); 636 req->r_pages_from_pool = 1; 637 WARN_ON(!req->r_pages); 638 } 639 } 640 641 /* 642 * initiate async writeback 643 */ 644 static int ceph_writepages_start(struct address_space *mapping, 645 struct writeback_control *wbc) 646 { 647 struct inode *inode = mapping->host; 648 struct ceph_inode_info *ci = ceph_inode(inode); 649 struct ceph_fs_client *fsc; 650 pgoff_t index, start, end; 651 int range_whole = 0; 652 int should_loop = 1; 653 pgoff_t max_pages = 0, max_pages_ever = 0; 654 struct ceph_snap_context *snapc = NULL, *last_snapc = NULL, *pgsnapc; 655 struct pagevec pvec; 656 int done = 0; 657 int rc = 0; 658 unsigned wsize = 1 << inode->i_blkbits; 659 struct ceph_osd_request *req = NULL; 660 int do_sync; 661 u64 snap_size = 0; 662 663 /* 664 * Include a 'sync' in the OSD request if this is a data 665 * integrity write (e.g., O_SYNC write or fsync()), or if our 666 * cap is being revoked. 667 */ 668 do_sync = wbc->sync_mode == WB_SYNC_ALL; 669 if (ceph_caps_revoking(ci, CEPH_CAP_FILE_BUFFER)) 670 do_sync = 1; 671 dout("writepages_start %p dosync=%d (mode=%s)\n", 672 inode, do_sync, 673 wbc->sync_mode == WB_SYNC_NONE ? "NONE" : 674 (wbc->sync_mode == WB_SYNC_ALL ? "ALL" : "HOLD")); 675 676 fsc = ceph_inode_to_client(inode); 677 if (fsc->mount_state == CEPH_MOUNT_SHUTDOWN) { 678 pr_warning("writepage_start %p on forced umount\n", inode); 679 return -EIO; /* we're in a forced umount, don't write! */ 680 } 681 if (fsc->mount_options->wsize && fsc->mount_options->wsize < wsize) 682 wsize = fsc->mount_options->wsize; 683 if (wsize < PAGE_CACHE_SIZE) 684 wsize = PAGE_CACHE_SIZE; 685 max_pages_ever = wsize >> PAGE_CACHE_SHIFT; 686 687 pagevec_init(&pvec, 0); 688 689 /* where to start/end? */ 690 if (wbc->range_cyclic) { 691 start = mapping->writeback_index; /* Start from prev offset */ 692 end = -1; 693 dout(" cyclic, start at %lu\n", start); 694 } else { 695 start = wbc->range_start >> PAGE_CACHE_SHIFT; 696 end = wbc->range_end >> PAGE_CACHE_SHIFT; 697 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) 698 range_whole = 1; 699 should_loop = 0; 700 dout(" not cyclic, %lu to %lu\n", start, end); 701 } 702 index = start; 703 704 retry: 705 /* find oldest snap context with dirty data */ 706 ceph_put_snap_context(snapc); 707 snapc = get_oldest_context(inode, &snap_size); 708 if (!snapc) { 709 /* hmm, why does writepages get called when there 710 is no dirty data? */ 711 dout(" no snap context with dirty data?\n"); 712 goto out; 713 } 714 dout(" oldest snapc is %p seq %lld (%d snaps)\n", 715 snapc, snapc->seq, snapc->num_snaps); 716 if (last_snapc && snapc != last_snapc) { 717 /* if we switched to a newer snapc, restart our scan at the 718 * start of the original file range. */ 719 dout(" snapc differs from last pass, restarting at %lu\n", 720 index); 721 index = start; 722 } 723 last_snapc = snapc; 724 725 while (!done && index <= end) { 726 unsigned i; 727 int first; 728 pgoff_t next; 729 int pvec_pages, locked_pages; 730 struct page *page; 731 int want; 732 u64 offset, len; 733 struct ceph_osd_request_head *reqhead; 734 struct ceph_osd_op *op; 735 long writeback_stat; 736 737 next = 0; 738 locked_pages = 0; 739 max_pages = max_pages_ever; 740 741 get_more_pages: 742 first = -1; 743 want = min(end - index, 744 min((pgoff_t)PAGEVEC_SIZE, 745 max_pages - (pgoff_t)locked_pages) - 1) 746 + 1; 747 pvec_pages = pagevec_lookup_tag(&pvec, mapping, &index, 748 PAGECACHE_TAG_DIRTY, 749 want); 750 dout("pagevec_lookup_tag got %d\n", pvec_pages); 751 if (!pvec_pages && !locked_pages) 752 break; 753 for (i = 0; i < pvec_pages && locked_pages < max_pages; i++) { 754 page = pvec.pages[i]; 755 dout("? %p idx %lu\n", page, page->index); 756 if (locked_pages == 0) 757 lock_page(page); /* first page */ 758 else if (!trylock_page(page)) 759 break; 760 761 /* only dirty pages, or our accounting breaks */ 762 if (unlikely(!PageDirty(page)) || 763 unlikely(page->mapping != mapping)) { 764 dout("!dirty or !mapping %p\n", page); 765 unlock_page(page); 766 break; 767 } 768 if (!wbc->range_cyclic && page->index > end) { 769 dout("end of range %p\n", page); 770 done = 1; 771 unlock_page(page); 772 break; 773 } 774 if (next && (page->index != next)) { 775 dout("not consecutive %p\n", page); 776 unlock_page(page); 777 break; 778 } 779 if (wbc->sync_mode != WB_SYNC_NONE) { 780 dout("waiting on writeback %p\n", page); 781 wait_on_page_writeback(page); 782 } 783 if ((snap_size && page_offset(page) > snap_size) || 784 (!snap_size && 785 page_offset(page) > i_size_read(inode))) { 786 dout("%p page eof %llu\n", page, snap_size ? 787 snap_size : i_size_read(inode)); 788 done = 1; 789 unlock_page(page); 790 break; 791 } 792 if (PageWriteback(page)) { 793 dout("%p under writeback\n", page); 794 unlock_page(page); 795 break; 796 } 797 798 /* only if matching snap context */ 799 pgsnapc = (void *)page->private; 800 if (pgsnapc->seq > snapc->seq) { 801 dout("page snapc %p %lld > oldest %p %lld\n", 802 pgsnapc, pgsnapc->seq, snapc, snapc->seq); 803 unlock_page(page); 804 if (!locked_pages) 805 continue; /* keep looking for snap */ 806 break; 807 } 808 809 if (!clear_page_dirty_for_io(page)) { 810 dout("%p !clear_page_dirty_for_io\n", page); 811 unlock_page(page); 812 break; 813 } 814 815 /* ok */ 816 if (locked_pages == 0) { 817 /* prepare async write request */ 818 offset = (unsigned long long)page->index 819 << PAGE_CACHE_SHIFT; 820 len = wsize; 821 req = ceph_osdc_new_request(&fsc->client->osdc, 822 &ci->i_layout, 823 ceph_vino(inode), 824 offset, &len, 825 CEPH_OSD_OP_WRITE, 826 CEPH_OSD_FLAG_WRITE | 827 CEPH_OSD_FLAG_ONDISK, 828 snapc, do_sync, 829 ci->i_truncate_seq, 830 ci->i_truncate_size, 831 &inode->i_mtime, true, 1, 0); 832 833 if (!req) { 834 rc = -ENOMEM; 835 unlock_page(page); 836 break; 837 } 838 839 max_pages = req->r_num_pages; 840 841 alloc_page_vec(fsc, req); 842 req->r_callback = writepages_finish; 843 req->r_inode = inode; 844 } 845 846 /* note position of first page in pvec */ 847 if (first < 0) 848 first = i; 849 dout("%p will write page %p idx %lu\n", 850 inode, page, page->index); 851 852 writeback_stat = 853 atomic_long_inc_return(&fsc->writeback_count); 854 if (writeback_stat > CONGESTION_ON_THRESH( 855 fsc->mount_options->congestion_kb)) { 856 set_bdi_congested(&fsc->backing_dev_info, 857 BLK_RW_ASYNC); 858 } 859 860 set_page_writeback(page); 861 req->r_pages[locked_pages] = page; 862 locked_pages++; 863 next = page->index + 1; 864 } 865 866 /* did we get anything? */ 867 if (!locked_pages) 868 goto release_pvec_pages; 869 if (i) { 870 int j; 871 BUG_ON(!locked_pages || first < 0); 872 873 if (pvec_pages && i == pvec_pages && 874 locked_pages < max_pages) { 875 dout("reached end pvec, trying for more\n"); 876 pagevec_reinit(&pvec); 877 goto get_more_pages; 878 } 879 880 /* shift unused pages over in the pvec... we 881 * will need to release them below. */ 882 for (j = i; j < pvec_pages; j++) { 883 dout(" pvec leftover page %p\n", 884 pvec.pages[j]); 885 pvec.pages[j-i+first] = pvec.pages[j]; 886 } 887 pvec.nr -= i-first; 888 } 889 890 /* submit the write */ 891 offset = req->r_pages[0]->index << PAGE_CACHE_SHIFT; 892 len = min((snap_size ? snap_size : i_size_read(inode)) - offset, 893 (u64)locked_pages << PAGE_CACHE_SHIFT); 894 dout("writepages got %d pages at %llu~%llu\n", 895 locked_pages, offset, len); 896 897 /* revise final length, page count */ 898 req->r_num_pages = locked_pages; 899 reqhead = req->r_request->front.iov_base; 900 op = (void *)(reqhead + 1); 901 op->extent.length = cpu_to_le64(len); 902 op->payload_len = cpu_to_le32(len); 903 req->r_request->hdr.data_len = cpu_to_le32(len); 904 905 rc = ceph_osdc_start_request(&fsc->client->osdc, req, true); 906 BUG_ON(rc); 907 req = NULL; 908 909 /* continue? */ 910 index = next; 911 wbc->nr_to_write -= locked_pages; 912 if (wbc->nr_to_write <= 0) 913 done = 1; 914 915 release_pvec_pages: 916 dout("pagevec_release on %d pages (%p)\n", (int)pvec.nr, 917 pvec.nr ? pvec.pages[0] : NULL); 918 pagevec_release(&pvec); 919 920 if (locked_pages && !done) 921 goto retry; 922 } 923 924 if (should_loop && !done) { 925 /* more to do; loop back to beginning of file */ 926 dout("writepages looping back to beginning of file\n"); 927 should_loop = 0; 928 index = 0; 929 goto retry; 930 } 931 932 if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0)) 933 mapping->writeback_index = index; 934 935 out: 936 if (req) 937 ceph_osdc_put_request(req); 938 ceph_put_snap_context(snapc); 939 dout("writepages done, rc = %d\n", rc); 940 return rc; 941 } 942 943 944 945 /* 946 * See if a given @snapc is either writeable, or already written. 947 */ 948 static int context_is_writeable_or_written(struct inode *inode, 949 struct ceph_snap_context *snapc) 950 { 951 struct ceph_snap_context *oldest = get_oldest_context(inode, NULL); 952 int ret = !oldest || snapc->seq <= oldest->seq; 953 954 ceph_put_snap_context(oldest); 955 return ret; 956 } 957 958 /* 959 * We are only allowed to write into/dirty the page if the page is 960 * clean, or already dirty within the same snap context. 961 * 962 * called with page locked. 963 * return success with page locked, 964 * or any failure (incl -EAGAIN) with page unlocked. 965 */ 966 static int ceph_update_writeable_page(struct file *file, 967 loff_t pos, unsigned len, 968 struct page *page) 969 { 970 struct inode *inode = file->f_dentry->d_inode; 971 struct ceph_inode_info *ci = ceph_inode(inode); 972 struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc; 973 loff_t page_off = pos & PAGE_CACHE_MASK; 974 int pos_in_page = pos & ~PAGE_CACHE_MASK; 975 int end_in_page = pos_in_page + len; 976 loff_t i_size; 977 int r; 978 struct ceph_snap_context *snapc, *oldest; 979 980 retry_locked: 981 /* writepages currently holds page lock, but if we change that later, */ 982 wait_on_page_writeback(page); 983 984 /* check snap context */ 985 BUG_ON(!ci->i_snap_realm); 986 down_read(&mdsc->snap_rwsem); 987 BUG_ON(!ci->i_snap_realm->cached_context); 988 snapc = (void *)page->private; 989 if (snapc && snapc != ci->i_head_snapc) { 990 /* 991 * this page is already dirty in another (older) snap 992 * context! is it writeable now? 993 */ 994 oldest = get_oldest_context(inode, NULL); 995 up_read(&mdsc->snap_rwsem); 996 997 if (snapc->seq > oldest->seq) { 998 ceph_put_snap_context(oldest); 999 dout(" page %p snapc %p not current or oldest\n", 1000 page, snapc); 1001 /* 1002 * queue for writeback, and wait for snapc to 1003 * be writeable or written 1004 */ 1005 snapc = ceph_get_snap_context(snapc); 1006 unlock_page(page); 1007 ceph_queue_writeback(inode); 1008 r = wait_event_interruptible(ci->i_cap_wq, 1009 context_is_writeable_or_written(inode, snapc)); 1010 ceph_put_snap_context(snapc); 1011 if (r == -ERESTARTSYS) 1012 return r; 1013 return -EAGAIN; 1014 } 1015 ceph_put_snap_context(oldest); 1016 1017 /* yay, writeable, do it now (without dropping page lock) */ 1018 dout(" page %p snapc %p not current, but oldest\n", 1019 page, snapc); 1020 if (!clear_page_dirty_for_io(page)) 1021 goto retry_locked; 1022 r = writepage_nounlock(page, NULL); 1023 if (r < 0) 1024 goto fail_nosnap; 1025 goto retry_locked; 1026 } 1027 1028 if (PageUptodate(page)) { 1029 dout(" page %p already uptodate\n", page); 1030 return 0; 1031 } 1032 1033 /* full page? */ 1034 if (pos_in_page == 0 && len == PAGE_CACHE_SIZE) 1035 return 0; 1036 1037 /* past end of file? */ 1038 i_size = inode->i_size; /* caller holds i_mutex */ 1039 1040 if (i_size + len > inode->i_sb->s_maxbytes) { 1041 /* file is too big */ 1042 r = -EINVAL; 1043 goto fail; 1044 } 1045 1046 if (page_off >= i_size || 1047 (pos_in_page == 0 && (pos+len) >= i_size && 1048 end_in_page - pos_in_page != PAGE_CACHE_SIZE)) { 1049 dout(" zeroing %p 0 - %d and %d - %d\n", 1050 page, pos_in_page, end_in_page, (int)PAGE_CACHE_SIZE); 1051 zero_user_segments(page, 1052 0, pos_in_page, 1053 end_in_page, PAGE_CACHE_SIZE); 1054 return 0; 1055 } 1056 1057 /* we need to read it. */ 1058 up_read(&mdsc->snap_rwsem); 1059 r = readpage_nounlock(file, page); 1060 if (r < 0) 1061 goto fail_nosnap; 1062 goto retry_locked; 1063 1064 fail: 1065 up_read(&mdsc->snap_rwsem); 1066 fail_nosnap: 1067 unlock_page(page); 1068 return r; 1069 } 1070 1071 /* 1072 * We are only allowed to write into/dirty the page if the page is 1073 * clean, or already dirty within the same snap context. 1074 */ 1075 static int ceph_write_begin(struct file *file, struct address_space *mapping, 1076 loff_t pos, unsigned len, unsigned flags, 1077 struct page **pagep, void **fsdata) 1078 { 1079 struct inode *inode = file->f_dentry->d_inode; 1080 struct page *page; 1081 pgoff_t index = pos >> PAGE_CACHE_SHIFT; 1082 int r; 1083 1084 do { 1085 /* get a page */ 1086 page = grab_cache_page_write_begin(mapping, index, 0); 1087 if (!page) 1088 return -ENOMEM; 1089 *pagep = page; 1090 1091 dout("write_begin file %p inode %p page %p %d~%d\n", file, 1092 inode, page, (int)pos, (int)len); 1093 1094 r = ceph_update_writeable_page(file, pos, len, page); 1095 } while (r == -EAGAIN); 1096 1097 return r; 1098 } 1099 1100 /* 1101 * we don't do anything in here that simple_write_end doesn't do 1102 * except adjust dirty page accounting and drop read lock on 1103 * mdsc->snap_rwsem. 1104 */ 1105 static int ceph_write_end(struct file *file, struct address_space *mapping, 1106 loff_t pos, unsigned len, unsigned copied, 1107 struct page *page, void *fsdata) 1108 { 1109 struct inode *inode = file->f_dentry->d_inode; 1110 struct ceph_fs_client *fsc = ceph_inode_to_client(inode); 1111 struct ceph_mds_client *mdsc = fsc->mdsc; 1112 unsigned from = pos & (PAGE_CACHE_SIZE - 1); 1113 int check_cap = 0; 1114 1115 dout("write_end file %p inode %p page %p %d~%d (%d)\n", file, 1116 inode, page, (int)pos, (int)copied, (int)len); 1117 1118 /* zero the stale part of the page if we did a short copy */ 1119 if (copied < len) 1120 zero_user_segment(page, from+copied, len); 1121 1122 /* did file size increase? */ 1123 /* (no need for i_size_read(); we caller holds i_mutex */ 1124 if (pos+copied > inode->i_size) 1125 check_cap = ceph_inode_set_size(inode, pos+copied); 1126 1127 if (!PageUptodate(page)) 1128 SetPageUptodate(page); 1129 1130 set_page_dirty(page); 1131 1132 unlock_page(page); 1133 up_read(&mdsc->snap_rwsem); 1134 page_cache_release(page); 1135 1136 if (check_cap) 1137 ceph_check_caps(ceph_inode(inode), CHECK_CAPS_AUTHONLY, NULL); 1138 1139 return copied; 1140 } 1141 1142 /* 1143 * we set .direct_IO to indicate direct io is supported, but since we 1144 * intercept O_DIRECT reads and writes early, this function should 1145 * never get called. 1146 */ 1147 static ssize_t ceph_direct_io(int rw, struct kiocb *iocb, 1148 const struct iovec *iov, 1149 loff_t pos, unsigned long nr_segs) 1150 { 1151 WARN_ON(1); 1152 return -EINVAL; 1153 } 1154 1155 const struct address_space_operations ceph_aops = { 1156 .readpage = ceph_readpage, 1157 .readpages = ceph_readpages, 1158 .writepage = ceph_writepage, 1159 .writepages = ceph_writepages_start, 1160 .write_begin = ceph_write_begin, 1161 .write_end = ceph_write_end, 1162 .set_page_dirty = ceph_set_page_dirty, 1163 .invalidatepage = ceph_invalidatepage, 1164 .releasepage = ceph_releasepage, 1165 .direct_IO = ceph_direct_io, 1166 }; 1167 1168 1169 /* 1170 * vm ops 1171 */ 1172 1173 /* 1174 * Reuse write_begin here for simplicity. 1175 */ 1176 static int ceph_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) 1177 { 1178 struct inode *inode = vma->vm_file->f_dentry->d_inode; 1179 struct page *page = vmf->page; 1180 struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc; 1181 loff_t off = page->index << PAGE_CACHE_SHIFT; 1182 loff_t size, len; 1183 int ret; 1184 1185 size = i_size_read(inode); 1186 if (off + PAGE_CACHE_SIZE <= size) 1187 len = PAGE_CACHE_SIZE; 1188 else 1189 len = size & ~PAGE_CACHE_MASK; 1190 1191 dout("page_mkwrite %p %llu~%llu page %p idx %lu\n", inode, 1192 off, len, page, page->index); 1193 1194 lock_page(page); 1195 1196 ret = VM_FAULT_NOPAGE; 1197 if ((off > size) || 1198 (page->mapping != inode->i_mapping)) 1199 goto out; 1200 1201 ret = ceph_update_writeable_page(vma->vm_file, off, len, page); 1202 if (ret == 0) { 1203 /* success. we'll keep the page locked. */ 1204 set_page_dirty(page); 1205 up_read(&mdsc->snap_rwsem); 1206 ret = VM_FAULT_LOCKED; 1207 } else { 1208 if (ret == -ENOMEM) 1209 ret = VM_FAULT_OOM; 1210 else 1211 ret = VM_FAULT_SIGBUS; 1212 } 1213 out: 1214 dout("page_mkwrite %p %llu~%llu = %d\n", inode, off, len, ret); 1215 if (ret != VM_FAULT_LOCKED) 1216 unlock_page(page); 1217 return ret; 1218 } 1219 1220 static struct vm_operations_struct ceph_vmops = { 1221 .fault = filemap_fault, 1222 .page_mkwrite = ceph_page_mkwrite, 1223 }; 1224 1225 int ceph_mmap(struct file *file, struct vm_area_struct *vma) 1226 { 1227 struct address_space *mapping = file->f_mapping; 1228 1229 if (!mapping->a_ops->readpage) 1230 return -ENOEXEC; 1231 file_accessed(file); 1232 vma->vm_ops = &ceph_vmops; 1233 vma->vm_flags |= VM_CAN_NONLINEAR; 1234 return 0; 1235 } 1236