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 static inline struct ceph_snap_context *page_snap_context(struct page *page) 58 { 59 if (PagePrivate(page)) 60 return (void *)page->private; 61 return NULL; 62 } 63 64 /* 65 * Dirty a page. Optimistically adjust accounting, on the assumption 66 * that we won't race with invalidate. If we do, readjust. 67 */ 68 static int ceph_set_page_dirty(struct page *page) 69 { 70 struct address_space *mapping = page->mapping; 71 struct inode *inode; 72 struct ceph_inode_info *ci; 73 int undo = 0; 74 struct ceph_snap_context *snapc; 75 76 if (unlikely(!mapping)) 77 return !TestSetPageDirty(page); 78 79 if (TestSetPageDirty(page)) { 80 dout("%p set_page_dirty %p idx %lu -- already dirty\n", 81 mapping->host, page, page->index); 82 return 0; 83 } 84 85 inode = mapping->host; 86 ci = ceph_inode(inode); 87 88 /* 89 * Note that we're grabbing a snapc ref here without holding 90 * any locks! 91 */ 92 snapc = ceph_get_snap_context(ci->i_snap_realm->cached_context); 93 94 /* dirty the head */ 95 spin_lock(&ci->i_ceph_lock); 96 if (ci->i_head_snapc == NULL) 97 ci->i_head_snapc = ceph_get_snap_context(snapc); 98 ++ci->i_wrbuffer_ref_head; 99 if (ci->i_wrbuffer_ref == 0) 100 ihold(inode); 101 ++ci->i_wrbuffer_ref; 102 dout("%p set_page_dirty %p idx %lu head %d/%d -> %d/%d " 103 "snapc %p seq %lld (%d snaps)\n", 104 mapping->host, page, page->index, 105 ci->i_wrbuffer_ref-1, ci->i_wrbuffer_ref_head-1, 106 ci->i_wrbuffer_ref, ci->i_wrbuffer_ref_head, 107 snapc, snapc->seq, snapc->num_snaps); 108 spin_unlock(&ci->i_ceph_lock); 109 110 /* now adjust page */ 111 spin_lock_irq(&mapping->tree_lock); 112 if (page->mapping) { /* Race with truncate? */ 113 WARN_ON_ONCE(!PageUptodate(page)); 114 account_page_dirtied(page, page->mapping); 115 radix_tree_tag_set(&mapping->page_tree, 116 page_index(page), PAGECACHE_TAG_DIRTY); 117 118 /* 119 * Reference snap context in page->private. Also set 120 * PagePrivate so that we get invalidatepage callback. 121 */ 122 page->private = (unsigned long)snapc; 123 SetPagePrivate(page); 124 } else { 125 dout("ANON set_page_dirty %p (raced truncate?)\n", page); 126 undo = 1; 127 } 128 129 spin_unlock_irq(&mapping->tree_lock); 130 131 if (undo) 132 /* whoops, we failed to dirty the page */ 133 ceph_put_wrbuffer_cap_refs(ci, 1, snapc); 134 135 __mark_inode_dirty(mapping->host, I_DIRTY_PAGES); 136 137 BUG_ON(!PageDirty(page)); 138 return 1; 139 } 140 141 /* 142 * If we are truncating the full page (i.e. offset == 0), adjust the 143 * dirty page counters appropriately. Only called if there is private 144 * data on the page. 145 */ 146 static void ceph_invalidatepage(struct page *page, unsigned long offset) 147 { 148 struct inode *inode; 149 struct ceph_inode_info *ci; 150 struct ceph_snap_context *snapc = page_snap_context(page); 151 152 BUG_ON(!PageLocked(page)); 153 BUG_ON(!PagePrivate(page)); 154 BUG_ON(!page->mapping); 155 156 inode = page->mapping->host; 157 158 /* 159 * We can get non-dirty pages here due to races between 160 * set_page_dirty and truncate_complete_page; just spit out a 161 * warning, in case we end up with accounting problems later. 162 */ 163 if (!PageDirty(page)) 164 pr_err("%p invalidatepage %p page not dirty\n", inode, page); 165 166 if (offset == 0) 167 ClearPageChecked(page); 168 169 ci = ceph_inode(inode); 170 if (offset == 0) { 171 dout("%p invalidatepage %p idx %lu full dirty page %lu\n", 172 inode, page, page->index, offset); 173 ceph_put_wrbuffer_cap_refs(ci, 1, snapc); 174 ceph_put_snap_context(snapc); 175 page->private = 0; 176 ClearPagePrivate(page); 177 } else { 178 dout("%p invalidatepage %p idx %lu partial dirty page\n", 179 inode, page, page->index); 180 } 181 } 182 183 /* just a sanity check */ 184 static int ceph_releasepage(struct page *page, gfp_t g) 185 { 186 struct inode *inode = page->mapping ? page->mapping->host : NULL; 187 dout("%p releasepage %p idx %lu\n", inode, page, page->index); 188 WARN_ON(PageDirty(page)); 189 WARN_ON(PagePrivate(page)); 190 return 0; 191 } 192 193 /* 194 * read a single page, without unlocking it. 195 */ 196 static int readpage_nounlock(struct file *filp, struct page *page) 197 { 198 struct inode *inode = file_inode(filp); 199 struct ceph_inode_info *ci = ceph_inode(inode); 200 struct ceph_osd_client *osdc = 201 &ceph_inode_to_client(inode)->client->osdc; 202 int err = 0; 203 u64 len = PAGE_CACHE_SIZE; 204 205 dout("readpage inode %p file %p page %p index %lu\n", 206 inode, filp, page, page->index); 207 err = ceph_osdc_readpages(osdc, ceph_vino(inode), &ci->i_layout, 208 (u64) page_offset(page), &len, 209 ci->i_truncate_seq, ci->i_truncate_size, 210 &page, 1, 0); 211 if (err == -ENOENT) 212 err = 0; 213 if (err < 0) { 214 SetPageError(page); 215 goto out; 216 } else if (err < PAGE_CACHE_SIZE) { 217 /* zero fill remainder of page */ 218 zero_user_segment(page, err, PAGE_CACHE_SIZE); 219 } 220 SetPageUptodate(page); 221 222 out: 223 return err < 0 ? err : 0; 224 } 225 226 static int ceph_readpage(struct file *filp, struct page *page) 227 { 228 int r = readpage_nounlock(filp, page); 229 unlock_page(page); 230 return r; 231 } 232 233 /* 234 * Finish an async read(ahead) op. 235 */ 236 static void finish_read(struct ceph_osd_request *req, struct ceph_msg *msg) 237 { 238 struct inode *inode = req->r_inode; 239 struct ceph_osd_data *osd_data; 240 int rc = req->r_result; 241 int bytes = le32_to_cpu(msg->hdr.data_len); 242 int num_pages; 243 int i; 244 245 dout("finish_read %p req %p rc %d bytes %d\n", inode, req, rc, bytes); 246 247 /* unlock all pages, zeroing any data we didn't read */ 248 osd_data = &req->r_data_in; 249 BUG_ON(osd_data->type != CEPH_OSD_DATA_TYPE_PAGES); 250 num_pages = calc_pages_for((u64)osd_data->alignment, 251 (u64)osd_data->length); 252 for (i = 0; i < num_pages; i++) { 253 struct page *page = osd_data->pages[i]; 254 255 if (bytes < (int)PAGE_CACHE_SIZE) { 256 /* zero (remainder of) page */ 257 int s = bytes < 0 ? 0 : bytes; 258 zero_user_segment(page, s, PAGE_CACHE_SIZE); 259 } 260 dout("finish_read %p uptodate %p idx %lu\n", inode, page, 261 page->index); 262 flush_dcache_page(page); 263 SetPageUptodate(page); 264 unlock_page(page); 265 page_cache_release(page); 266 bytes -= PAGE_CACHE_SIZE; 267 } 268 kfree(osd_data->pages); 269 } 270 271 static void ceph_unlock_page_vector(struct page **pages, int num_pages) 272 { 273 int i; 274 275 for (i = 0; i < num_pages; i++) 276 unlock_page(pages[i]); 277 } 278 279 /* 280 * start an async read(ahead) operation. return nr_pages we submitted 281 * a read for on success, or negative error code. 282 */ 283 static int start_read(struct inode *inode, struct list_head *page_list, int max) 284 { 285 struct ceph_osd_client *osdc = 286 &ceph_inode_to_client(inode)->client->osdc; 287 struct ceph_inode_info *ci = ceph_inode(inode); 288 struct page *page = list_entry(page_list->prev, struct page, lru); 289 struct ceph_vino vino; 290 struct ceph_osd_request *req; 291 struct ceph_osd_req_op op; 292 u64 off; 293 u64 len; 294 int i; 295 struct page **pages; 296 pgoff_t next_index; 297 int nr_pages = 0; 298 int ret; 299 300 off = (u64) page_offset(page); 301 302 /* count pages */ 303 next_index = page->index; 304 list_for_each_entry_reverse(page, page_list, lru) { 305 if (page->index != next_index) 306 break; 307 nr_pages++; 308 next_index++; 309 if (max && nr_pages == max) 310 break; 311 } 312 len = nr_pages << PAGE_CACHE_SHIFT; 313 dout("start_read %p nr_pages %d is %lld~%lld\n", inode, nr_pages, 314 off, len); 315 vino = ceph_vino(inode); 316 req = ceph_osdc_new_request(osdc, &ci->i_layout, vino, off, &len, 317 1, &op, CEPH_OSD_OP_READ, 318 CEPH_OSD_FLAG_READ, NULL, 319 ci->i_truncate_seq, ci->i_truncate_size, 320 false); 321 if (IS_ERR(req)) 322 return PTR_ERR(req); 323 324 /* build page vector */ 325 nr_pages = calc_pages_for(0, len); 326 pages = kmalloc(sizeof(*pages) * nr_pages, GFP_NOFS); 327 ret = -ENOMEM; 328 if (!pages) 329 goto out; 330 for (i = 0; i < nr_pages; ++i) { 331 page = list_entry(page_list->prev, struct page, lru); 332 BUG_ON(PageLocked(page)); 333 list_del(&page->lru); 334 335 dout("start_read %p adding %p idx %lu\n", inode, page, 336 page->index); 337 if (add_to_page_cache_lru(page, &inode->i_data, page->index, 338 GFP_NOFS)) { 339 page_cache_release(page); 340 dout("start_read %p add_to_page_cache failed %p\n", 341 inode, page); 342 nr_pages = i; 343 goto out_pages; 344 } 345 pages[i] = page; 346 } 347 ceph_osd_data_pages_init(&req->r_data_in, pages, len, 0, 348 false, false); 349 req->r_callback = finish_read; 350 req->r_inode = inode; 351 352 ceph_osdc_build_request(req, off, 1, &op, NULL, vino.snap, NULL); 353 354 dout("start_read %p starting %p %lld~%lld\n", inode, req, off, len); 355 ret = ceph_osdc_start_request(osdc, req, false); 356 if (ret < 0) 357 goto out_pages; 358 ceph_osdc_put_request(req); 359 return nr_pages; 360 361 out_pages: 362 ceph_unlock_page_vector(pages, nr_pages); 363 ceph_release_page_vector(pages, nr_pages); 364 out: 365 ceph_osdc_put_request(req); 366 return ret; 367 } 368 369 370 /* 371 * Read multiple pages. Leave pages we don't read + unlock in page_list; 372 * the caller (VM) cleans them up. 373 */ 374 static int ceph_readpages(struct file *file, struct address_space *mapping, 375 struct list_head *page_list, unsigned nr_pages) 376 { 377 struct inode *inode = file_inode(file); 378 struct ceph_fs_client *fsc = ceph_inode_to_client(inode); 379 int rc = 0; 380 int max = 0; 381 382 if (fsc->mount_options->rsize >= PAGE_CACHE_SIZE) 383 max = (fsc->mount_options->rsize + PAGE_CACHE_SIZE - 1) 384 >> PAGE_SHIFT; 385 386 dout("readpages %p file %p nr_pages %d max %d\n", inode, 387 file, nr_pages, 388 max); 389 while (!list_empty(page_list)) { 390 rc = start_read(inode, page_list, max); 391 if (rc < 0) 392 goto out; 393 BUG_ON(rc == 0); 394 } 395 out: 396 dout("readpages %p file %p ret %d\n", inode, file, rc); 397 return rc; 398 } 399 400 /* 401 * Get ref for the oldest snapc for an inode with dirty data... that is, the 402 * only snap context we are allowed to write back. 403 */ 404 static struct ceph_snap_context *get_oldest_context(struct inode *inode, 405 u64 *snap_size) 406 { 407 struct ceph_inode_info *ci = ceph_inode(inode); 408 struct ceph_snap_context *snapc = NULL; 409 struct ceph_cap_snap *capsnap = NULL; 410 411 spin_lock(&ci->i_ceph_lock); 412 list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) { 413 dout(" cap_snap %p snapc %p has %d dirty pages\n", capsnap, 414 capsnap->context, capsnap->dirty_pages); 415 if (capsnap->dirty_pages) { 416 snapc = ceph_get_snap_context(capsnap->context); 417 if (snap_size) 418 *snap_size = capsnap->size; 419 break; 420 } 421 } 422 if (!snapc && ci->i_wrbuffer_ref_head) { 423 snapc = ceph_get_snap_context(ci->i_head_snapc); 424 dout(" head snapc %p has %d dirty pages\n", 425 snapc, ci->i_wrbuffer_ref_head); 426 } 427 spin_unlock(&ci->i_ceph_lock); 428 return snapc; 429 } 430 431 /* 432 * Write a single page, but leave the page locked. 433 * 434 * If we get a write error, set the page error bit, but still adjust the 435 * dirty page accounting (i.e., page is no longer dirty). 436 */ 437 static int writepage_nounlock(struct page *page, struct writeback_control *wbc) 438 { 439 struct inode *inode; 440 struct ceph_inode_info *ci; 441 struct ceph_fs_client *fsc; 442 struct ceph_osd_client *osdc; 443 loff_t page_off = page_offset(page); 444 int len = PAGE_CACHE_SIZE; 445 loff_t i_size; 446 int err = 0; 447 struct ceph_snap_context *snapc, *oldest; 448 u64 snap_size = 0; 449 long writeback_stat; 450 451 dout("writepage %p idx %lu\n", page, page->index); 452 453 if (!page->mapping || !page->mapping->host) { 454 dout("writepage %p - no mapping\n", page); 455 return -EFAULT; 456 } 457 inode = page->mapping->host; 458 ci = ceph_inode(inode); 459 fsc = ceph_inode_to_client(inode); 460 osdc = &fsc->client->osdc; 461 462 /* verify this is a writeable snap context */ 463 snapc = page_snap_context(page); 464 if (snapc == NULL) { 465 dout("writepage %p page %p not dirty?\n", inode, page); 466 goto out; 467 } 468 oldest = get_oldest_context(inode, &snap_size); 469 if (snapc->seq > oldest->seq) { 470 dout("writepage %p page %p snapc %p not writeable - noop\n", 471 inode, page, snapc); 472 /* we should only noop if called by kswapd */ 473 WARN_ON((current->flags & PF_MEMALLOC) == 0); 474 ceph_put_snap_context(oldest); 475 goto out; 476 } 477 ceph_put_snap_context(oldest); 478 479 /* is this a partial page at end of file? */ 480 if (snap_size) 481 i_size = snap_size; 482 else 483 i_size = i_size_read(inode); 484 if (i_size < page_off + len) 485 len = i_size - page_off; 486 487 dout("writepage %p page %p index %lu on %llu~%u snapc %p\n", 488 inode, page, page->index, page_off, len, snapc); 489 490 writeback_stat = atomic_long_inc_return(&fsc->writeback_count); 491 if (writeback_stat > 492 CONGESTION_ON_THRESH(fsc->mount_options->congestion_kb)) 493 set_bdi_congested(&fsc->backing_dev_info, BLK_RW_ASYNC); 494 495 set_page_writeback(page); 496 err = ceph_osdc_writepages(osdc, ceph_vino(inode), 497 &ci->i_layout, snapc, 498 page_off, len, 499 ci->i_truncate_seq, ci->i_truncate_size, 500 &inode->i_mtime, &page, 1); 501 if (err < 0) { 502 dout("writepage setting page/mapping error %d %p\n", err, page); 503 SetPageError(page); 504 mapping_set_error(&inode->i_data, err); 505 if (wbc) 506 wbc->pages_skipped++; 507 } else { 508 dout("writepage cleaned page %p\n", page); 509 err = 0; /* vfs expects us to return 0 */ 510 } 511 page->private = 0; 512 ClearPagePrivate(page); 513 end_page_writeback(page); 514 ceph_put_wrbuffer_cap_refs(ci, 1, snapc); 515 ceph_put_snap_context(snapc); /* page's reference */ 516 out: 517 return err; 518 } 519 520 static int ceph_writepage(struct page *page, struct writeback_control *wbc) 521 { 522 int err; 523 struct inode *inode = page->mapping->host; 524 BUG_ON(!inode); 525 ihold(inode); 526 err = writepage_nounlock(page, wbc); 527 unlock_page(page); 528 iput(inode); 529 return err; 530 } 531 532 533 /* 534 * lame release_pages helper. release_pages() isn't exported to 535 * modules. 536 */ 537 static void ceph_release_pages(struct page **pages, int num) 538 { 539 struct pagevec pvec; 540 int i; 541 542 pagevec_init(&pvec, 0); 543 for (i = 0; i < num; i++) { 544 if (pagevec_add(&pvec, pages[i]) == 0) 545 pagevec_release(&pvec); 546 } 547 pagevec_release(&pvec); 548 } 549 550 551 /* 552 * async writeback completion handler. 553 * 554 * If we get an error, set the mapping error bit, but not the individual 555 * page error bits. 556 */ 557 static void writepages_finish(struct ceph_osd_request *req, 558 struct ceph_msg *msg) 559 { 560 struct inode *inode = req->r_inode; 561 struct ceph_inode_info *ci = ceph_inode(inode); 562 struct ceph_osd_data *osd_data; 563 unsigned wrote; 564 struct page *page; 565 int num_pages; 566 int i; 567 struct ceph_snap_context *snapc = req->r_snapc; 568 struct address_space *mapping = inode->i_mapping; 569 int rc = req->r_result; 570 u64 bytes = le64_to_cpu(req->r_request_ops[0].extent.length); 571 struct ceph_fs_client *fsc = ceph_inode_to_client(inode); 572 long writeback_stat; 573 unsigned issued = ceph_caps_issued(ci); 574 575 osd_data = &req->r_data_out; 576 BUG_ON(osd_data->type != CEPH_OSD_DATA_TYPE_PAGES); 577 num_pages = calc_pages_for((u64)osd_data->alignment, 578 (u64)osd_data->length); 579 if (rc >= 0) { 580 /* 581 * Assume we wrote the pages we originally sent. The 582 * osd might reply with fewer pages if our writeback 583 * raced with a truncation and was adjusted at the osd, 584 * so don't believe the reply. 585 */ 586 wrote = num_pages; 587 } else { 588 wrote = 0; 589 mapping_set_error(mapping, rc); 590 } 591 dout("writepages_finish %p rc %d bytes %llu wrote %d (pages)\n", 592 inode, rc, bytes, wrote); 593 594 /* clean all pages */ 595 for (i = 0; i < num_pages; i++) { 596 page = osd_data->pages[i]; 597 BUG_ON(!page); 598 WARN_ON(!PageUptodate(page)); 599 600 writeback_stat = 601 atomic_long_dec_return(&fsc->writeback_count); 602 if (writeback_stat < 603 CONGESTION_OFF_THRESH(fsc->mount_options->congestion_kb)) 604 clear_bdi_congested(&fsc->backing_dev_info, 605 BLK_RW_ASYNC); 606 607 ceph_put_snap_context(page_snap_context(page)); 608 page->private = 0; 609 ClearPagePrivate(page); 610 dout("unlocking %d %p\n", i, page); 611 end_page_writeback(page); 612 613 /* 614 * We lost the cache cap, need to truncate the page before 615 * it is unlocked, otherwise we'd truncate it later in the 616 * page truncation thread, possibly losing some data that 617 * raced its way in 618 */ 619 if ((issued & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) == 0) 620 generic_error_remove_page(inode->i_mapping, page); 621 622 unlock_page(page); 623 } 624 dout("%p wrote+cleaned %d pages\n", inode, wrote); 625 ceph_put_wrbuffer_cap_refs(ci, num_pages, snapc); 626 627 ceph_release_pages(osd_data->pages, num_pages); 628 if (osd_data->pages_from_pool) 629 mempool_free(osd_data->pages, 630 ceph_sb_to_client(inode->i_sb)->wb_pagevec_pool); 631 else 632 kfree(osd_data->pages); 633 ceph_osdc_put_request(req); 634 } 635 636 static struct ceph_osd_request * 637 ceph_writepages_osd_request(struct inode *inode, u64 offset, u64 *len, 638 struct ceph_snap_context *snapc, 639 int num_ops, struct ceph_osd_req_op *ops) 640 { 641 struct ceph_fs_client *fsc; 642 struct ceph_inode_info *ci; 643 struct ceph_vino vino; 644 645 fsc = ceph_inode_to_client(inode); 646 ci = ceph_inode(inode); 647 vino = ceph_vino(inode); 648 /* BUG_ON(vino.snap != CEPH_NOSNAP); */ 649 650 return ceph_osdc_new_request(&fsc->client->osdc, &ci->i_layout, 651 vino, offset, len, num_ops, ops, CEPH_OSD_OP_WRITE, 652 CEPH_OSD_FLAG_WRITE|CEPH_OSD_FLAG_ONDISK, 653 snapc, ci->i_truncate_seq, ci->i_truncate_size, true); 654 } 655 656 /* 657 * initiate async writeback 658 */ 659 static int ceph_writepages_start(struct address_space *mapping, 660 struct writeback_control *wbc) 661 { 662 struct inode *inode = mapping->host; 663 struct ceph_inode_info *ci = ceph_inode(inode); 664 struct ceph_fs_client *fsc; 665 pgoff_t index, start, end; 666 int range_whole = 0; 667 int should_loop = 1; 668 pgoff_t max_pages = 0, max_pages_ever = 0; 669 struct ceph_snap_context *snapc = NULL, *last_snapc = NULL, *pgsnapc; 670 struct pagevec pvec; 671 int done = 0; 672 int rc = 0; 673 unsigned wsize = 1 << inode->i_blkbits; 674 struct ceph_osd_request *req = NULL; 675 int do_sync; 676 u64 snap_size = 0; 677 678 /* 679 * Include a 'sync' in the OSD request if this is a data 680 * integrity write (e.g., O_SYNC write or fsync()), or if our 681 * cap is being revoked. 682 */ 683 do_sync = wbc->sync_mode == WB_SYNC_ALL; 684 if (ceph_caps_revoking(ci, CEPH_CAP_FILE_BUFFER)) 685 do_sync = 1; 686 dout("writepages_start %p dosync=%d (mode=%s)\n", 687 inode, do_sync, 688 wbc->sync_mode == WB_SYNC_NONE ? "NONE" : 689 (wbc->sync_mode == WB_SYNC_ALL ? "ALL" : "HOLD")); 690 691 fsc = ceph_inode_to_client(inode); 692 if (fsc->mount_state == CEPH_MOUNT_SHUTDOWN) { 693 pr_warning("writepage_start %p on forced umount\n", inode); 694 return -EIO; /* we're in a forced umount, don't write! */ 695 } 696 if (fsc->mount_options->wsize && fsc->mount_options->wsize < wsize) 697 wsize = fsc->mount_options->wsize; 698 if (wsize < PAGE_CACHE_SIZE) 699 wsize = PAGE_CACHE_SIZE; 700 max_pages_ever = wsize >> PAGE_CACHE_SHIFT; 701 702 pagevec_init(&pvec, 0); 703 704 /* where to start/end? */ 705 if (wbc->range_cyclic) { 706 start = mapping->writeback_index; /* Start from prev offset */ 707 end = -1; 708 dout(" cyclic, start at %lu\n", start); 709 } else { 710 start = wbc->range_start >> PAGE_CACHE_SHIFT; 711 end = wbc->range_end >> PAGE_CACHE_SHIFT; 712 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) 713 range_whole = 1; 714 should_loop = 0; 715 dout(" not cyclic, %lu to %lu\n", start, end); 716 } 717 index = start; 718 719 retry: 720 /* find oldest snap context with dirty data */ 721 ceph_put_snap_context(snapc); 722 snapc = get_oldest_context(inode, &snap_size); 723 if (!snapc) { 724 /* hmm, why does writepages get called when there 725 is no dirty data? */ 726 dout(" no snap context with dirty data?\n"); 727 goto out; 728 } 729 dout(" oldest snapc is %p seq %lld (%d snaps)\n", 730 snapc, snapc->seq, snapc->num_snaps); 731 if (last_snapc && snapc != last_snapc) { 732 /* if we switched to a newer snapc, restart our scan at the 733 * start of the original file range. */ 734 dout(" snapc differs from last pass, restarting at %lu\n", 735 index); 736 index = start; 737 } 738 last_snapc = snapc; 739 740 while (!done && index <= end) { 741 struct ceph_osd_req_op ops[2]; 742 int num_ops = do_sync ? 2 : 1; 743 struct ceph_vino vino; 744 unsigned i; 745 int first; 746 pgoff_t next; 747 int pvec_pages, locked_pages; 748 struct page **pages = NULL; 749 mempool_t *pool = NULL; /* Becomes non-null if mempool used */ 750 struct page *page; 751 int want; 752 u64 offset, len; 753 long writeback_stat; 754 755 next = 0; 756 locked_pages = 0; 757 max_pages = max_pages_ever; 758 759 get_more_pages: 760 first = -1; 761 want = min(end - index, 762 min((pgoff_t)PAGEVEC_SIZE, 763 max_pages - (pgoff_t)locked_pages) - 1) 764 + 1; 765 pvec_pages = pagevec_lookup_tag(&pvec, mapping, &index, 766 PAGECACHE_TAG_DIRTY, 767 want); 768 dout("pagevec_lookup_tag got %d\n", pvec_pages); 769 if (!pvec_pages && !locked_pages) 770 break; 771 for (i = 0; i < pvec_pages && locked_pages < max_pages; i++) { 772 page = pvec.pages[i]; 773 dout("? %p idx %lu\n", page, page->index); 774 if (locked_pages == 0) 775 lock_page(page); /* first page */ 776 else if (!trylock_page(page)) 777 break; 778 779 /* only dirty pages, or our accounting breaks */ 780 if (unlikely(!PageDirty(page)) || 781 unlikely(page->mapping != mapping)) { 782 dout("!dirty or !mapping %p\n", page); 783 unlock_page(page); 784 break; 785 } 786 if (!wbc->range_cyclic && page->index > end) { 787 dout("end of range %p\n", page); 788 done = 1; 789 unlock_page(page); 790 break; 791 } 792 if (next && (page->index != next)) { 793 dout("not consecutive %p\n", page); 794 unlock_page(page); 795 break; 796 } 797 if (wbc->sync_mode != WB_SYNC_NONE) { 798 dout("waiting on writeback %p\n", page); 799 wait_on_page_writeback(page); 800 } 801 if ((snap_size && page_offset(page) > snap_size) || 802 (!snap_size && 803 page_offset(page) > i_size_read(inode))) { 804 dout("%p page eof %llu\n", page, snap_size ? 805 snap_size : i_size_read(inode)); 806 done = 1; 807 unlock_page(page); 808 break; 809 } 810 if (PageWriteback(page)) { 811 dout("%p under writeback\n", page); 812 unlock_page(page); 813 break; 814 } 815 816 /* only if matching snap context */ 817 pgsnapc = page_snap_context(page); 818 if (pgsnapc->seq > snapc->seq) { 819 dout("page snapc %p %lld > oldest %p %lld\n", 820 pgsnapc, pgsnapc->seq, snapc, snapc->seq); 821 unlock_page(page); 822 if (!locked_pages) 823 continue; /* keep looking for snap */ 824 break; 825 } 826 827 if (!clear_page_dirty_for_io(page)) { 828 dout("%p !clear_page_dirty_for_io\n", page); 829 unlock_page(page); 830 break; 831 } 832 833 /* 834 * We have something to write. If this is 835 * the first locked page this time through, 836 * allocate an osd request and a page array 837 * that it will use. 838 */ 839 if (locked_pages == 0) { 840 size_t size; 841 842 BUG_ON(pages); 843 844 /* prepare async write request */ 845 offset = (u64)page_offset(page); 846 len = wsize; 847 req = ceph_writepages_osd_request(inode, 848 offset, &len, snapc, 849 num_ops, ops); 850 851 if (IS_ERR(req)) { 852 rc = PTR_ERR(req); 853 unlock_page(page); 854 break; 855 } 856 857 req->r_callback = writepages_finish; 858 req->r_inode = inode; 859 860 max_pages = calc_pages_for(0, (u64)len); 861 size = max_pages * sizeof (*pages); 862 pages = kmalloc(size, GFP_NOFS); 863 if (!pages) { 864 pool = fsc->wb_pagevec_pool; 865 pages = mempool_alloc(pool, GFP_NOFS); 866 BUG_ON(!pages); 867 } 868 } 869 870 /* note position of first page in pvec */ 871 if (first < 0) 872 first = i; 873 dout("%p will write page %p idx %lu\n", 874 inode, page, page->index); 875 876 writeback_stat = 877 atomic_long_inc_return(&fsc->writeback_count); 878 if (writeback_stat > CONGESTION_ON_THRESH( 879 fsc->mount_options->congestion_kb)) { 880 set_bdi_congested(&fsc->backing_dev_info, 881 BLK_RW_ASYNC); 882 } 883 884 set_page_writeback(page); 885 pages[locked_pages] = page; 886 locked_pages++; 887 next = page->index + 1; 888 } 889 890 /* did we get anything? */ 891 if (!locked_pages) 892 goto release_pvec_pages; 893 if (i) { 894 int j; 895 BUG_ON(!locked_pages || first < 0); 896 897 if (pvec_pages && i == pvec_pages && 898 locked_pages < max_pages) { 899 dout("reached end pvec, trying for more\n"); 900 pagevec_reinit(&pvec); 901 goto get_more_pages; 902 } 903 904 /* shift unused pages over in the pvec... we 905 * will need to release them below. */ 906 for (j = i; j < pvec_pages; j++) { 907 dout(" pvec leftover page %p\n", 908 pvec.pages[j]); 909 pvec.pages[j-i+first] = pvec.pages[j]; 910 } 911 pvec.nr -= i-first; 912 } 913 914 /* Format the osd request message and submit the write */ 915 916 offset = page_offset(pages[0]); 917 len = min((snap_size ? snap_size : i_size_read(inode)) - offset, 918 (u64)locked_pages << PAGE_CACHE_SHIFT); 919 dout("writepages got %d pages at %llu~%llu\n", 920 locked_pages, offset, len); 921 922 ceph_osd_data_pages_init(&req->r_data_out, pages, len, 0, 923 !!pool, false); 924 925 pages = NULL; /* request message now owns the pages array */ 926 pool = NULL; 927 928 /* Update the write op length in case we changed it */ 929 930 osd_req_op_extent_update(&ops[0], len); 931 932 vino = ceph_vino(inode); 933 ceph_osdc_build_request(req, offset, num_ops, ops, 934 snapc, vino.snap, &inode->i_mtime); 935 936 rc = ceph_osdc_start_request(&fsc->client->osdc, req, true); 937 BUG_ON(rc); 938 req = NULL; 939 940 /* continue? */ 941 index = next; 942 wbc->nr_to_write -= locked_pages; 943 if (wbc->nr_to_write <= 0) 944 done = 1; 945 946 release_pvec_pages: 947 dout("pagevec_release on %d pages (%p)\n", (int)pvec.nr, 948 pvec.nr ? pvec.pages[0] : NULL); 949 pagevec_release(&pvec); 950 951 if (locked_pages && !done) 952 goto retry; 953 } 954 955 if (should_loop && !done) { 956 /* more to do; loop back to beginning of file */ 957 dout("writepages looping back to beginning of file\n"); 958 should_loop = 0; 959 index = 0; 960 goto retry; 961 } 962 963 if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0)) 964 mapping->writeback_index = index; 965 966 out: 967 if (req) 968 ceph_osdc_put_request(req); 969 ceph_put_snap_context(snapc); 970 dout("writepages done, rc = %d\n", rc); 971 return rc; 972 } 973 974 975 976 /* 977 * See if a given @snapc is either writeable, or already written. 978 */ 979 static int context_is_writeable_or_written(struct inode *inode, 980 struct ceph_snap_context *snapc) 981 { 982 struct ceph_snap_context *oldest = get_oldest_context(inode, NULL); 983 int ret = !oldest || snapc->seq <= oldest->seq; 984 985 ceph_put_snap_context(oldest); 986 return ret; 987 } 988 989 /* 990 * We are only allowed to write into/dirty the page if the page is 991 * clean, or already dirty within the same snap context. 992 * 993 * called with page locked. 994 * return success with page locked, 995 * or any failure (incl -EAGAIN) with page unlocked. 996 */ 997 static int ceph_update_writeable_page(struct file *file, 998 loff_t pos, unsigned len, 999 struct page *page) 1000 { 1001 struct inode *inode = file_inode(file); 1002 struct ceph_inode_info *ci = ceph_inode(inode); 1003 struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc; 1004 loff_t page_off = pos & PAGE_CACHE_MASK; 1005 int pos_in_page = pos & ~PAGE_CACHE_MASK; 1006 int end_in_page = pos_in_page + len; 1007 loff_t i_size; 1008 int r; 1009 struct ceph_snap_context *snapc, *oldest; 1010 1011 retry_locked: 1012 /* writepages currently holds page lock, but if we change that later, */ 1013 wait_on_page_writeback(page); 1014 1015 /* check snap context */ 1016 BUG_ON(!ci->i_snap_realm); 1017 down_read(&mdsc->snap_rwsem); 1018 BUG_ON(!ci->i_snap_realm->cached_context); 1019 snapc = page_snap_context(page); 1020 if (snapc && snapc != ci->i_head_snapc) { 1021 /* 1022 * this page is already dirty in another (older) snap 1023 * context! is it writeable now? 1024 */ 1025 oldest = get_oldest_context(inode, NULL); 1026 up_read(&mdsc->snap_rwsem); 1027 1028 if (snapc->seq > oldest->seq) { 1029 ceph_put_snap_context(oldest); 1030 dout(" page %p snapc %p not current or oldest\n", 1031 page, snapc); 1032 /* 1033 * queue for writeback, and wait for snapc to 1034 * be writeable or written 1035 */ 1036 snapc = ceph_get_snap_context(snapc); 1037 unlock_page(page); 1038 ceph_queue_writeback(inode); 1039 r = wait_event_interruptible(ci->i_cap_wq, 1040 context_is_writeable_or_written(inode, snapc)); 1041 ceph_put_snap_context(snapc); 1042 if (r == -ERESTARTSYS) 1043 return r; 1044 return -EAGAIN; 1045 } 1046 ceph_put_snap_context(oldest); 1047 1048 /* yay, writeable, do it now (without dropping page lock) */ 1049 dout(" page %p snapc %p not current, but oldest\n", 1050 page, snapc); 1051 if (!clear_page_dirty_for_io(page)) 1052 goto retry_locked; 1053 r = writepage_nounlock(page, NULL); 1054 if (r < 0) 1055 goto fail_nosnap; 1056 goto retry_locked; 1057 } 1058 1059 if (PageUptodate(page)) { 1060 dout(" page %p already uptodate\n", page); 1061 return 0; 1062 } 1063 1064 /* full page? */ 1065 if (pos_in_page == 0 && len == PAGE_CACHE_SIZE) 1066 return 0; 1067 1068 /* past end of file? */ 1069 i_size = inode->i_size; /* caller holds i_mutex */ 1070 1071 if (i_size + len > inode->i_sb->s_maxbytes) { 1072 /* file is too big */ 1073 r = -EINVAL; 1074 goto fail; 1075 } 1076 1077 if (page_off >= i_size || 1078 (pos_in_page == 0 && (pos+len) >= i_size && 1079 end_in_page - pos_in_page != PAGE_CACHE_SIZE)) { 1080 dout(" zeroing %p 0 - %d and %d - %d\n", 1081 page, pos_in_page, end_in_page, (int)PAGE_CACHE_SIZE); 1082 zero_user_segments(page, 1083 0, pos_in_page, 1084 end_in_page, PAGE_CACHE_SIZE); 1085 return 0; 1086 } 1087 1088 /* we need to read it. */ 1089 up_read(&mdsc->snap_rwsem); 1090 r = readpage_nounlock(file, page); 1091 if (r < 0) 1092 goto fail_nosnap; 1093 goto retry_locked; 1094 1095 fail: 1096 up_read(&mdsc->snap_rwsem); 1097 fail_nosnap: 1098 unlock_page(page); 1099 return r; 1100 } 1101 1102 /* 1103 * We are only allowed to write into/dirty the page if the page is 1104 * clean, or already dirty within the same snap context. 1105 */ 1106 static int ceph_write_begin(struct file *file, struct address_space *mapping, 1107 loff_t pos, unsigned len, unsigned flags, 1108 struct page **pagep, void **fsdata) 1109 { 1110 struct inode *inode = file_inode(file); 1111 struct page *page; 1112 pgoff_t index = pos >> PAGE_CACHE_SHIFT; 1113 int r; 1114 1115 do { 1116 /* get a page */ 1117 page = grab_cache_page_write_begin(mapping, index, 0); 1118 if (!page) 1119 return -ENOMEM; 1120 *pagep = page; 1121 1122 dout("write_begin file %p inode %p page %p %d~%d\n", file, 1123 inode, page, (int)pos, (int)len); 1124 1125 r = ceph_update_writeable_page(file, pos, len, page); 1126 } while (r == -EAGAIN); 1127 1128 return r; 1129 } 1130 1131 /* 1132 * we don't do anything in here that simple_write_end doesn't do 1133 * except adjust dirty page accounting and drop read lock on 1134 * mdsc->snap_rwsem. 1135 */ 1136 static int ceph_write_end(struct file *file, struct address_space *mapping, 1137 loff_t pos, unsigned len, unsigned copied, 1138 struct page *page, void *fsdata) 1139 { 1140 struct inode *inode = file_inode(file); 1141 struct ceph_fs_client *fsc = ceph_inode_to_client(inode); 1142 struct ceph_mds_client *mdsc = fsc->mdsc; 1143 unsigned from = pos & (PAGE_CACHE_SIZE - 1); 1144 int check_cap = 0; 1145 1146 dout("write_end file %p inode %p page %p %d~%d (%d)\n", file, 1147 inode, page, (int)pos, (int)copied, (int)len); 1148 1149 /* zero the stale part of the page if we did a short copy */ 1150 if (copied < len) 1151 zero_user_segment(page, from+copied, len); 1152 1153 /* did file size increase? */ 1154 /* (no need for i_size_read(); we caller holds i_mutex */ 1155 if (pos+copied > inode->i_size) 1156 check_cap = ceph_inode_set_size(inode, pos+copied); 1157 1158 if (!PageUptodate(page)) 1159 SetPageUptodate(page); 1160 1161 set_page_dirty(page); 1162 1163 unlock_page(page); 1164 up_read(&mdsc->snap_rwsem); 1165 page_cache_release(page); 1166 1167 if (check_cap) 1168 ceph_check_caps(ceph_inode(inode), CHECK_CAPS_AUTHONLY, NULL); 1169 1170 return copied; 1171 } 1172 1173 /* 1174 * we set .direct_IO to indicate direct io is supported, but since we 1175 * intercept O_DIRECT reads and writes early, this function should 1176 * never get called. 1177 */ 1178 static ssize_t ceph_direct_io(int rw, struct kiocb *iocb, 1179 const struct iovec *iov, 1180 loff_t pos, unsigned long nr_segs) 1181 { 1182 WARN_ON(1); 1183 return -EINVAL; 1184 } 1185 1186 const struct address_space_operations ceph_aops = { 1187 .readpage = ceph_readpage, 1188 .readpages = ceph_readpages, 1189 .writepage = ceph_writepage, 1190 .writepages = ceph_writepages_start, 1191 .write_begin = ceph_write_begin, 1192 .write_end = ceph_write_end, 1193 .set_page_dirty = ceph_set_page_dirty, 1194 .invalidatepage = ceph_invalidatepage, 1195 .releasepage = ceph_releasepage, 1196 .direct_IO = ceph_direct_io, 1197 }; 1198 1199 1200 /* 1201 * vm ops 1202 */ 1203 1204 /* 1205 * Reuse write_begin here for simplicity. 1206 */ 1207 static int ceph_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) 1208 { 1209 struct inode *inode = file_inode(vma->vm_file); 1210 struct page *page = vmf->page; 1211 struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc; 1212 loff_t off = page_offset(page); 1213 loff_t size, len; 1214 int ret; 1215 1216 /* Update time before taking page lock */ 1217 file_update_time(vma->vm_file); 1218 1219 size = i_size_read(inode); 1220 if (off + PAGE_CACHE_SIZE <= size) 1221 len = PAGE_CACHE_SIZE; 1222 else 1223 len = size & ~PAGE_CACHE_MASK; 1224 1225 dout("page_mkwrite %p %llu~%llu page %p idx %lu\n", inode, 1226 off, len, page, page->index); 1227 1228 lock_page(page); 1229 1230 ret = VM_FAULT_NOPAGE; 1231 if ((off > size) || 1232 (page->mapping != inode->i_mapping)) 1233 goto out; 1234 1235 ret = ceph_update_writeable_page(vma->vm_file, off, len, page); 1236 if (ret == 0) { 1237 /* success. we'll keep the page locked. */ 1238 set_page_dirty(page); 1239 up_read(&mdsc->snap_rwsem); 1240 ret = VM_FAULT_LOCKED; 1241 } else { 1242 if (ret == -ENOMEM) 1243 ret = VM_FAULT_OOM; 1244 else 1245 ret = VM_FAULT_SIGBUS; 1246 } 1247 out: 1248 dout("page_mkwrite %p %llu~%llu = %d\n", inode, off, len, ret); 1249 if (ret != VM_FAULT_LOCKED) 1250 unlock_page(page); 1251 return ret; 1252 } 1253 1254 static struct vm_operations_struct ceph_vmops = { 1255 .fault = filemap_fault, 1256 .page_mkwrite = ceph_page_mkwrite, 1257 .remap_pages = generic_file_remap_pages, 1258 }; 1259 1260 int ceph_mmap(struct file *file, struct vm_area_struct *vma) 1261 { 1262 struct address_space *mapping = file->f_mapping; 1263 1264 if (!mapping->a_ops->readpage) 1265 return -ENOEXEC; 1266 file_accessed(file); 1267 vma->vm_ops = &ceph_vmops; 1268 return 0; 1269 } 1270