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 "cache.h" 15 #include <linux/ceph/osd_client.h> 16 17 /* 18 * Ceph address space ops. 19 * 20 * There are a few funny things going on here. 21 * 22 * The page->private field is used to reference a struct 23 * ceph_snap_context for _every_ dirty page. This indicates which 24 * snapshot the page was logically dirtied in, and thus which snap 25 * context needs to be associated with the osd write during writeback. 26 * 27 * Similarly, struct ceph_inode_info maintains a set of counters to 28 * count dirty pages on the inode. In the absence of snapshots, 29 * i_wrbuffer_ref == i_wrbuffer_ref_head == the dirty page count. 30 * 31 * When a snapshot is taken (that is, when the client receives 32 * notification that a snapshot was taken), each inode with caps and 33 * with dirty pages (dirty pages implies there is a cap) gets a new 34 * ceph_cap_snap in the i_cap_snaps list (which is sorted in ascending 35 * order, new snaps go to the tail). The i_wrbuffer_ref_head count is 36 * moved to capsnap->dirty. (Unless a sync write is currently in 37 * progress. In that case, the capsnap is said to be "pending", new 38 * writes cannot start, and the capsnap isn't "finalized" until the 39 * write completes (or fails) and a final size/mtime for the inode for 40 * that snap can be settled upon.) i_wrbuffer_ref_head is reset to 0. 41 * 42 * On writeback, we must submit writes to the osd IN SNAP ORDER. So, 43 * we look for the first capsnap in i_cap_snaps and write out pages in 44 * that snap context _only_. Then we move on to the next capsnap, 45 * eventually reaching the "live" or "head" context (i.e., pages that 46 * are not yet snapped) and are writing the most recently dirtied 47 * pages. 48 * 49 * Invalidate and so forth must take care to ensure the dirty page 50 * accounting is preserved. 51 */ 52 53 #define CONGESTION_ON_THRESH(congestion_kb) (congestion_kb >> (PAGE_SHIFT-10)) 54 #define CONGESTION_OFF_THRESH(congestion_kb) \ 55 (CONGESTION_ON_THRESH(congestion_kb) - \ 56 (CONGESTION_ON_THRESH(congestion_kb) >> 2)) 57 58 static inline struct ceph_snap_context *page_snap_context(struct page *page) 59 { 60 if (PagePrivate(page)) 61 return (void *)page->private; 62 return NULL; 63 } 64 65 /* 66 * Dirty a page. Optimistically adjust accounting, on the assumption 67 * that we won't race with invalidate. If we do, readjust. 68 */ 69 static int ceph_set_page_dirty(struct page *page) 70 { 71 struct address_space *mapping = page->mapping; 72 struct inode *inode; 73 struct ceph_inode_info *ci; 74 struct ceph_snap_context *snapc; 75 int ret; 76 77 if (unlikely(!mapping)) 78 return !TestSetPageDirty(page); 79 80 if (PageDirty(page)) { 81 dout("%p set_page_dirty %p idx %lu -- already dirty\n", 82 mapping->host, page, page->index); 83 BUG_ON(!PagePrivate(page)); 84 return 0; 85 } 86 87 inode = mapping->host; 88 ci = ceph_inode(inode); 89 90 /* 91 * Note that we're grabbing a snapc ref here without holding 92 * any locks! 93 */ 94 snapc = ceph_get_snap_context(ci->i_snap_realm->cached_context); 95 96 /* dirty the head */ 97 spin_lock(&ci->i_ceph_lock); 98 if (ci->i_head_snapc == NULL) 99 ci->i_head_snapc = ceph_get_snap_context(snapc); 100 ++ci->i_wrbuffer_ref_head; 101 if (ci->i_wrbuffer_ref == 0) 102 ihold(inode); 103 ++ci->i_wrbuffer_ref; 104 dout("%p set_page_dirty %p idx %lu head %d/%d -> %d/%d " 105 "snapc %p seq %lld (%d snaps)\n", 106 mapping->host, page, page->index, 107 ci->i_wrbuffer_ref-1, ci->i_wrbuffer_ref_head-1, 108 ci->i_wrbuffer_ref, ci->i_wrbuffer_ref_head, 109 snapc, snapc->seq, snapc->num_snaps); 110 spin_unlock(&ci->i_ceph_lock); 111 112 /* 113 * Reference snap context in page->private. Also set 114 * PagePrivate so that we get invalidatepage callback. 115 */ 116 BUG_ON(PagePrivate(page)); 117 page->private = (unsigned long)snapc; 118 SetPagePrivate(page); 119 120 ret = __set_page_dirty_nobuffers(page); 121 WARN_ON(!PageLocked(page)); 122 WARN_ON(!page->mapping); 123 124 return ret; 125 } 126 127 /* 128 * If we are truncating the full page (i.e. offset == 0), adjust the 129 * dirty page counters appropriately. Only called if there is private 130 * data on the page. 131 */ 132 static void ceph_invalidatepage(struct page *page, unsigned int offset, 133 unsigned int length) 134 { 135 struct inode *inode; 136 struct ceph_inode_info *ci; 137 struct ceph_snap_context *snapc = page_snap_context(page); 138 139 inode = page->mapping->host; 140 ci = ceph_inode(inode); 141 142 if (offset != 0 || length != PAGE_CACHE_SIZE) { 143 dout("%p invalidatepage %p idx %lu partial dirty page %u~%u\n", 144 inode, page, page->index, offset, length); 145 return; 146 } 147 148 ceph_invalidate_fscache_page(inode, page); 149 150 if (!PagePrivate(page)) 151 return; 152 153 /* 154 * We can get non-dirty pages here due to races between 155 * set_page_dirty and truncate_complete_page; just spit out a 156 * warning, in case we end up with accounting problems later. 157 */ 158 if (!PageDirty(page)) 159 pr_err("%p invalidatepage %p page not dirty\n", inode, page); 160 161 ClearPageChecked(page); 162 163 dout("%p invalidatepage %p idx %lu full dirty page\n", 164 inode, page, page->index); 165 166 ceph_put_wrbuffer_cap_refs(ci, 1, snapc); 167 ceph_put_snap_context(snapc); 168 page->private = 0; 169 ClearPagePrivate(page); 170 } 171 172 static int ceph_releasepage(struct page *page, gfp_t g) 173 { 174 struct inode *inode = page->mapping ? page->mapping->host : NULL; 175 dout("%p releasepage %p idx %lu\n", inode, page, page->index); 176 WARN_ON(PageDirty(page)); 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 /* 186 * read a single page, without unlocking it. 187 */ 188 static int readpage_nounlock(struct file *filp, struct page *page) 189 { 190 struct inode *inode = file_inode(filp); 191 struct ceph_inode_info *ci = ceph_inode(inode); 192 struct ceph_osd_client *osdc = 193 &ceph_inode_to_client(inode)->client->osdc; 194 int err = 0; 195 u64 len = PAGE_CACHE_SIZE; 196 197 err = ceph_readpage_from_fscache(inode, page); 198 199 if (err == 0) 200 goto out; 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 (u64) page_offset(page), &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 if (err >= 0) 220 ceph_readpage_to_fscache(inode, 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 = osd_req_op_extent_osd_data(req, 0); 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 ceph_readpage_to_fscache(inode, page); 265 unlock_page(page); 266 page_cache_release(page); 267 bytes -= PAGE_CACHE_SIZE; 268 } 269 kfree(osd_data->pages); 270 } 271 272 static void ceph_unlock_page_vector(struct page **pages, int num_pages) 273 { 274 int i; 275 276 for (i = 0; i < num_pages; i++) 277 unlock_page(pages[i]); 278 } 279 280 /* 281 * start an async read(ahead) operation. return nr_pages we submitted 282 * a read for on success, or negative error code. 283 */ 284 static int start_read(struct inode *inode, struct list_head *page_list, int max) 285 { 286 struct ceph_osd_client *osdc = 287 &ceph_inode_to_client(inode)->client->osdc; 288 struct ceph_inode_info *ci = ceph_inode(inode); 289 struct page *page = list_entry(page_list->prev, struct page, lru); 290 struct ceph_vino vino; 291 struct ceph_osd_request *req; 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, 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 ceph_fscache_uncache_page(inode, page); 340 page_cache_release(page); 341 dout("start_read %p add_to_page_cache failed %p\n", 342 inode, page); 343 nr_pages = i; 344 goto out_pages; 345 } 346 pages[i] = page; 347 } 348 osd_req_op_extent_osd_data_pages(req, 0, pages, len, 0, false, false); 349 req->r_callback = finish_read; 350 req->r_inode = inode; 351 352 ceph_osdc_build_request(req, off, 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 rc = ceph_readpages_from_fscache(mapping->host, mapping, page_list, 383 &nr_pages); 384 385 if (rc == 0) 386 goto out; 387 388 if (fsc->mount_options->rsize >= PAGE_CACHE_SIZE) 389 max = (fsc->mount_options->rsize + PAGE_CACHE_SIZE - 1) 390 >> PAGE_SHIFT; 391 392 dout("readpages %p file %p nr_pages %d max %d\n", inode, 393 file, nr_pages, 394 max); 395 while (!list_empty(page_list)) { 396 rc = start_read(inode, page_list, max); 397 if (rc < 0) 398 goto out; 399 BUG_ON(rc == 0); 400 } 401 out: 402 ceph_fscache_readpages_cancel(inode, page_list); 403 404 dout("readpages %p file %p ret %d\n", inode, file, rc); 405 return rc; 406 } 407 408 /* 409 * Get ref for the oldest snapc for an inode with dirty data... that is, the 410 * only snap context we are allowed to write back. 411 */ 412 static struct ceph_snap_context *get_oldest_context(struct inode *inode, 413 u64 *snap_size) 414 { 415 struct ceph_inode_info *ci = ceph_inode(inode); 416 struct ceph_snap_context *snapc = NULL; 417 struct ceph_cap_snap *capsnap = NULL; 418 419 spin_lock(&ci->i_ceph_lock); 420 list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) { 421 dout(" cap_snap %p snapc %p has %d dirty pages\n", capsnap, 422 capsnap->context, capsnap->dirty_pages); 423 if (capsnap->dirty_pages) { 424 snapc = ceph_get_snap_context(capsnap->context); 425 if (snap_size) 426 *snap_size = capsnap->size; 427 break; 428 } 429 } 430 if (!snapc && ci->i_wrbuffer_ref_head) { 431 snapc = ceph_get_snap_context(ci->i_head_snapc); 432 dout(" head snapc %p has %d dirty pages\n", 433 snapc, ci->i_wrbuffer_ref_head); 434 } 435 spin_unlock(&ci->i_ceph_lock); 436 return snapc; 437 } 438 439 /* 440 * Write a single page, but leave the page locked. 441 * 442 * If we get a write error, set the page error bit, but still adjust the 443 * dirty page accounting (i.e., page is no longer dirty). 444 */ 445 static int writepage_nounlock(struct page *page, struct writeback_control *wbc) 446 { 447 struct inode *inode; 448 struct ceph_inode_info *ci; 449 struct ceph_fs_client *fsc; 450 struct ceph_osd_client *osdc; 451 struct ceph_snap_context *snapc, *oldest; 452 loff_t page_off = page_offset(page); 453 long writeback_stat; 454 u64 truncate_size, snap_size = 0; 455 u32 truncate_seq; 456 int err = 0, len = PAGE_CACHE_SIZE; 457 458 dout("writepage %p idx %lu\n", page, page->index); 459 460 if (!page->mapping || !page->mapping->host) { 461 dout("writepage %p - no mapping\n", page); 462 return -EFAULT; 463 } 464 inode = page->mapping->host; 465 ci = ceph_inode(inode); 466 fsc = ceph_inode_to_client(inode); 467 osdc = &fsc->client->osdc; 468 469 /* verify this is a writeable snap context */ 470 snapc = page_snap_context(page); 471 if (snapc == NULL) { 472 dout("writepage %p page %p not dirty?\n", inode, page); 473 goto out; 474 } 475 oldest = get_oldest_context(inode, &snap_size); 476 if (snapc->seq > oldest->seq) { 477 dout("writepage %p page %p snapc %p not writeable - noop\n", 478 inode, page, snapc); 479 /* we should only noop if called by kswapd */ 480 WARN_ON((current->flags & PF_MEMALLOC) == 0); 481 ceph_put_snap_context(oldest); 482 goto out; 483 } 484 ceph_put_snap_context(oldest); 485 486 spin_lock(&ci->i_ceph_lock); 487 truncate_seq = ci->i_truncate_seq; 488 truncate_size = ci->i_truncate_size; 489 if (!snap_size) 490 snap_size = i_size_read(inode); 491 spin_unlock(&ci->i_ceph_lock); 492 493 /* is this a partial page at end of file? */ 494 if (page_off >= snap_size) { 495 dout("%p page eof %llu\n", page, snap_size); 496 goto out; 497 } 498 if (snap_size < page_off + len) 499 len = snap_size - page_off; 500 501 dout("writepage %p page %p index %lu on %llu~%u snapc %p\n", 502 inode, page, page->index, page_off, len, snapc); 503 504 writeback_stat = atomic_long_inc_return(&fsc->writeback_count); 505 if (writeback_stat > 506 CONGESTION_ON_THRESH(fsc->mount_options->congestion_kb)) 507 set_bdi_congested(&fsc->backing_dev_info, BLK_RW_ASYNC); 508 509 ceph_readpage_to_fscache(inode, page); 510 511 set_page_writeback(page); 512 err = ceph_osdc_writepages(osdc, ceph_vino(inode), 513 &ci->i_layout, snapc, 514 page_off, len, 515 truncate_seq, truncate_size, 516 &inode->i_mtime, &page, 1); 517 if (err < 0) { 518 dout("writepage setting page/mapping error %d %p\n", err, page); 519 SetPageError(page); 520 mapping_set_error(&inode->i_data, err); 521 if (wbc) 522 wbc->pages_skipped++; 523 } else { 524 dout("writepage cleaned page %p\n", page); 525 err = 0; /* vfs expects us to return 0 */ 526 } 527 page->private = 0; 528 ClearPagePrivate(page); 529 end_page_writeback(page); 530 ceph_put_wrbuffer_cap_refs(ci, 1, snapc); 531 ceph_put_snap_context(snapc); /* page's reference */ 532 out: 533 return err; 534 } 535 536 static int ceph_writepage(struct page *page, struct writeback_control *wbc) 537 { 538 int err; 539 struct inode *inode = page->mapping->host; 540 BUG_ON(!inode); 541 ihold(inode); 542 err = writepage_nounlock(page, wbc); 543 unlock_page(page); 544 iput(inode); 545 return err; 546 } 547 548 549 /* 550 * lame release_pages helper. release_pages() isn't exported to 551 * modules. 552 */ 553 static void ceph_release_pages(struct page **pages, int num) 554 { 555 struct pagevec pvec; 556 int i; 557 558 pagevec_init(&pvec, 0); 559 for (i = 0; i < num; i++) { 560 if (pagevec_add(&pvec, pages[i]) == 0) 561 pagevec_release(&pvec); 562 } 563 pagevec_release(&pvec); 564 } 565 566 /* 567 * async writeback completion handler. 568 * 569 * If we get an error, set the mapping error bit, but not the individual 570 * page error bits. 571 */ 572 static void writepages_finish(struct ceph_osd_request *req, 573 struct ceph_msg *msg) 574 { 575 struct inode *inode = req->r_inode; 576 struct ceph_inode_info *ci = ceph_inode(inode); 577 struct ceph_osd_data *osd_data; 578 unsigned wrote; 579 struct page *page; 580 int num_pages; 581 int i; 582 struct ceph_snap_context *snapc = req->r_snapc; 583 struct address_space *mapping = inode->i_mapping; 584 int rc = req->r_result; 585 u64 bytes = req->r_ops[0].extent.length; 586 struct ceph_fs_client *fsc = ceph_inode_to_client(inode); 587 long writeback_stat; 588 unsigned issued = ceph_caps_issued(ci); 589 590 osd_data = osd_req_op_extent_osd_data(req, 0); 591 BUG_ON(osd_data->type != CEPH_OSD_DATA_TYPE_PAGES); 592 num_pages = calc_pages_for((u64)osd_data->alignment, 593 (u64)osd_data->length); 594 if (rc >= 0) { 595 /* 596 * Assume we wrote the pages we originally sent. The 597 * osd might reply with fewer pages if our writeback 598 * raced with a truncation and was adjusted at the osd, 599 * so don't believe the reply. 600 */ 601 wrote = num_pages; 602 } else { 603 wrote = 0; 604 mapping_set_error(mapping, rc); 605 } 606 dout("writepages_finish %p rc %d bytes %llu wrote %d (pages)\n", 607 inode, rc, bytes, wrote); 608 609 /* clean all pages */ 610 for (i = 0; i < num_pages; i++) { 611 page = osd_data->pages[i]; 612 BUG_ON(!page); 613 WARN_ON(!PageUptodate(page)); 614 615 writeback_stat = 616 atomic_long_dec_return(&fsc->writeback_count); 617 if (writeback_stat < 618 CONGESTION_OFF_THRESH(fsc->mount_options->congestion_kb)) 619 clear_bdi_congested(&fsc->backing_dev_info, 620 BLK_RW_ASYNC); 621 622 ceph_put_snap_context(page_snap_context(page)); 623 page->private = 0; 624 ClearPagePrivate(page); 625 dout("unlocking %d %p\n", i, page); 626 end_page_writeback(page); 627 628 /* 629 * We lost the cache cap, need to truncate the page before 630 * it is unlocked, otherwise we'd truncate it later in the 631 * page truncation thread, possibly losing some data that 632 * raced its way in 633 */ 634 if ((issued & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) == 0) 635 generic_error_remove_page(inode->i_mapping, page); 636 637 unlock_page(page); 638 } 639 dout("%p wrote+cleaned %d pages\n", inode, wrote); 640 ceph_put_wrbuffer_cap_refs(ci, num_pages, snapc); 641 642 ceph_release_pages(osd_data->pages, num_pages); 643 if (osd_data->pages_from_pool) 644 mempool_free(osd_data->pages, 645 ceph_sb_to_client(inode->i_sb)->wb_pagevec_pool); 646 else 647 kfree(osd_data->pages); 648 ceph_osdc_put_request(req); 649 } 650 651 /* 652 * initiate async writeback 653 */ 654 static int ceph_writepages_start(struct address_space *mapping, 655 struct writeback_control *wbc) 656 { 657 struct inode *inode = mapping->host; 658 struct ceph_inode_info *ci = ceph_inode(inode); 659 struct ceph_fs_client *fsc = ceph_inode_to_client(inode); 660 struct ceph_vino vino = ceph_vino(inode); 661 pgoff_t index, start, end; 662 int range_whole = 0; 663 int should_loop = 1; 664 pgoff_t max_pages = 0, max_pages_ever = 0; 665 struct ceph_snap_context *snapc = NULL, *last_snapc = NULL, *pgsnapc; 666 struct pagevec pvec; 667 int done = 0; 668 int rc = 0; 669 unsigned wsize = 1 << inode->i_blkbits; 670 struct ceph_osd_request *req = NULL; 671 int do_sync; 672 u64 truncate_size, snap_size; 673 u32 truncate_seq; 674 675 /* 676 * Include a 'sync' in the OSD request if this is a data 677 * integrity write (e.g., O_SYNC write or fsync()), or if our 678 * cap is being revoked. 679 */ 680 if ((wbc->sync_mode == WB_SYNC_ALL) || 681 ceph_caps_revoking(ci, CEPH_CAP_FILE_BUFFER)) 682 do_sync = 1; 683 dout("writepages_start %p dosync=%d (mode=%s)\n", 684 inode, do_sync, 685 wbc->sync_mode == WB_SYNC_NONE ? "NONE" : 686 (wbc->sync_mode == WB_SYNC_ALL ? "ALL" : "HOLD")); 687 688 if (fsc->mount_state == CEPH_MOUNT_SHUTDOWN) { 689 pr_warning("writepage_start %p on forced umount\n", inode); 690 return -EIO; /* we're in a forced umount, don't write! */ 691 } 692 if (fsc->mount_options->wsize && fsc->mount_options->wsize < wsize) 693 wsize = fsc->mount_options->wsize; 694 if (wsize < PAGE_CACHE_SIZE) 695 wsize = PAGE_CACHE_SIZE; 696 max_pages_ever = wsize >> PAGE_CACHE_SHIFT; 697 698 pagevec_init(&pvec, 0); 699 700 /* where to start/end? */ 701 if (wbc->range_cyclic) { 702 start = mapping->writeback_index; /* Start from prev offset */ 703 end = -1; 704 dout(" cyclic, start at %lu\n", start); 705 } else { 706 start = wbc->range_start >> PAGE_CACHE_SHIFT; 707 end = wbc->range_end >> PAGE_CACHE_SHIFT; 708 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) 709 range_whole = 1; 710 should_loop = 0; 711 dout(" not cyclic, %lu to %lu\n", start, end); 712 } 713 index = start; 714 715 retry: 716 /* find oldest snap context with dirty data */ 717 ceph_put_snap_context(snapc); 718 snap_size = 0; 719 snapc = get_oldest_context(inode, &snap_size); 720 if (!snapc) { 721 /* hmm, why does writepages get called when there 722 is no dirty data? */ 723 dout(" no snap context with dirty data?\n"); 724 goto out; 725 } 726 if (snap_size == 0) 727 snap_size = i_size_read(inode); 728 dout(" oldest snapc is %p seq %lld (%d snaps)\n", 729 snapc, snapc->seq, snapc->num_snaps); 730 731 spin_lock(&ci->i_ceph_lock); 732 truncate_seq = ci->i_truncate_seq; 733 truncate_size = ci->i_truncate_size; 734 if (!snap_size) 735 snap_size = i_size_read(inode); 736 spin_unlock(&ci->i_ceph_lock); 737 738 if (last_snapc && snapc != last_snapc) { 739 /* if we switched to a newer snapc, restart our scan at the 740 * start of the original file range. */ 741 dout(" snapc differs from last pass, restarting at %lu\n", 742 index); 743 index = start; 744 } 745 last_snapc = snapc; 746 747 while (!done && index <= end) { 748 int num_ops = do_sync ? 2 : 1; 749 unsigned i; 750 int first; 751 pgoff_t next; 752 int pvec_pages, locked_pages; 753 struct page **pages = NULL; 754 mempool_t *pool = NULL; /* Becomes non-null if mempool used */ 755 struct page *page; 756 int want; 757 u64 offset, len; 758 long writeback_stat; 759 760 next = 0; 761 locked_pages = 0; 762 max_pages = max_pages_ever; 763 764 get_more_pages: 765 first = -1; 766 want = min(end - index, 767 min((pgoff_t)PAGEVEC_SIZE, 768 max_pages - (pgoff_t)locked_pages) - 1) 769 + 1; 770 pvec_pages = pagevec_lookup_tag(&pvec, mapping, &index, 771 PAGECACHE_TAG_DIRTY, 772 want); 773 dout("pagevec_lookup_tag got %d\n", pvec_pages); 774 if (!pvec_pages && !locked_pages) 775 break; 776 for (i = 0; i < pvec_pages && locked_pages < max_pages; i++) { 777 page = pvec.pages[i]; 778 dout("? %p idx %lu\n", page, page->index); 779 if (locked_pages == 0) 780 lock_page(page); /* first page */ 781 else if (!trylock_page(page)) 782 break; 783 784 /* only dirty pages, or our accounting breaks */ 785 if (unlikely(!PageDirty(page)) || 786 unlikely(page->mapping != mapping)) { 787 dout("!dirty or !mapping %p\n", page); 788 unlock_page(page); 789 break; 790 } 791 if (!wbc->range_cyclic && page->index > end) { 792 dout("end of range %p\n", page); 793 done = 1; 794 unlock_page(page); 795 break; 796 } 797 if (next && (page->index != next)) { 798 dout("not consecutive %p\n", page); 799 unlock_page(page); 800 break; 801 } 802 if (wbc->sync_mode != WB_SYNC_NONE) { 803 dout("waiting on writeback %p\n", page); 804 wait_on_page_writeback(page); 805 } 806 if (page_offset(page) >= snap_size) { 807 dout("%p page eof %llu\n", page, snap_size); 808 done = 1; 809 unlock_page(page); 810 break; 811 } 812 if (PageWriteback(page)) { 813 dout("%p under writeback\n", page); 814 unlock_page(page); 815 break; 816 } 817 818 /* only if matching snap context */ 819 pgsnapc = page_snap_context(page); 820 if (pgsnapc->seq > snapc->seq) { 821 dout("page snapc %p %lld > oldest %p %lld\n", 822 pgsnapc, pgsnapc->seq, snapc, snapc->seq); 823 unlock_page(page); 824 if (!locked_pages) 825 continue; /* keep looking for snap */ 826 break; 827 } 828 829 if (!clear_page_dirty_for_io(page)) { 830 dout("%p !clear_page_dirty_for_io\n", page); 831 unlock_page(page); 832 break; 833 } 834 835 /* 836 * We have something to write. If this is 837 * the first locked page this time through, 838 * allocate an osd request and a page array 839 * that it will use. 840 */ 841 if (locked_pages == 0) { 842 BUG_ON(pages); 843 /* prepare async write request */ 844 offset = (u64)page_offset(page); 845 len = wsize; 846 req = ceph_osdc_new_request(&fsc->client->osdc, 847 &ci->i_layout, vino, 848 offset, &len, num_ops, 849 CEPH_OSD_OP_WRITE, 850 CEPH_OSD_FLAG_WRITE | 851 CEPH_OSD_FLAG_ONDISK, 852 snapc, truncate_seq, 853 truncate_size, true); 854 if (IS_ERR(req)) { 855 rc = PTR_ERR(req); 856 unlock_page(page); 857 break; 858 } 859 860 req->r_callback = writepages_finish; 861 req->r_inode = inode; 862 863 max_pages = calc_pages_for(0, (u64)len); 864 pages = kmalloc(max_pages * sizeof (*pages), 865 GFP_NOFS); 866 if (!pages) { 867 pool = fsc->wb_pagevec_pool; 868 pages = mempool_alloc(pool, GFP_NOFS); 869 BUG_ON(!pages); 870 } 871 } 872 873 /* note position of first page in pvec */ 874 if (first < 0) 875 first = i; 876 dout("%p will write page %p idx %lu\n", 877 inode, page, page->index); 878 879 writeback_stat = 880 atomic_long_inc_return(&fsc->writeback_count); 881 if (writeback_stat > CONGESTION_ON_THRESH( 882 fsc->mount_options->congestion_kb)) { 883 set_bdi_congested(&fsc->backing_dev_info, 884 BLK_RW_ASYNC); 885 } 886 887 set_page_writeback(page); 888 pages[locked_pages] = page; 889 locked_pages++; 890 next = page->index + 1; 891 } 892 893 /* did we get anything? */ 894 if (!locked_pages) 895 goto release_pvec_pages; 896 if (i) { 897 int j; 898 BUG_ON(!locked_pages || first < 0); 899 900 if (pvec_pages && i == pvec_pages && 901 locked_pages < max_pages) { 902 dout("reached end pvec, trying for more\n"); 903 pagevec_reinit(&pvec); 904 goto get_more_pages; 905 } 906 907 /* shift unused pages over in the pvec... we 908 * will need to release them below. */ 909 for (j = i; j < pvec_pages; j++) { 910 dout(" pvec leftover page %p\n", 911 pvec.pages[j]); 912 pvec.pages[j-i+first] = pvec.pages[j]; 913 } 914 pvec.nr -= i-first; 915 } 916 917 /* Format the osd request message and submit the write */ 918 919 offset = page_offset(pages[0]); 920 len = min(snap_size - offset, 921 (u64)locked_pages << PAGE_CACHE_SHIFT); 922 dout("writepages got %d pages at %llu~%llu\n", 923 locked_pages, offset, len); 924 925 osd_req_op_extent_osd_data_pages(req, 0, pages, len, 0, 926 !!pool, false); 927 928 pages = NULL; /* request message now owns the pages array */ 929 pool = NULL; 930 931 /* Update the write op length in case we changed it */ 932 933 osd_req_op_extent_update(req, 0, len); 934 935 vino = ceph_vino(inode); 936 ceph_osdc_build_request(req, offset, snapc, vino.snap, 937 &inode->i_mtime); 938 939 rc = ceph_osdc_start_request(&fsc->client->osdc, req, true); 940 BUG_ON(rc); 941 req = NULL; 942 943 /* continue? */ 944 index = next; 945 wbc->nr_to_write -= locked_pages; 946 if (wbc->nr_to_write <= 0) 947 done = 1; 948 949 release_pvec_pages: 950 dout("pagevec_release on %d pages (%p)\n", (int)pvec.nr, 951 pvec.nr ? pvec.pages[0] : NULL); 952 pagevec_release(&pvec); 953 954 if (locked_pages && !done) 955 goto retry; 956 } 957 958 if (should_loop && !done) { 959 /* more to do; loop back to beginning of file */ 960 dout("writepages looping back to beginning of file\n"); 961 should_loop = 0; 962 index = 0; 963 goto retry; 964 } 965 966 if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0)) 967 mapping->writeback_index = index; 968 969 out: 970 if (req) 971 ceph_osdc_put_request(req); 972 ceph_put_snap_context(snapc); 973 dout("writepages done, rc = %d\n", rc); 974 return rc; 975 } 976 977 978 979 /* 980 * See if a given @snapc is either writeable, or already written. 981 */ 982 static int context_is_writeable_or_written(struct inode *inode, 983 struct ceph_snap_context *snapc) 984 { 985 struct ceph_snap_context *oldest = get_oldest_context(inode, NULL); 986 int ret = !oldest || snapc->seq <= oldest->seq; 987 988 ceph_put_snap_context(oldest); 989 return ret; 990 } 991 992 /* 993 * We are only allowed to write into/dirty the page if the page is 994 * clean, or already dirty within the same snap context. 995 * 996 * called with page locked. 997 * return success with page locked, 998 * or any failure (incl -EAGAIN) with page unlocked. 999 */ 1000 static int ceph_update_writeable_page(struct file *file, 1001 loff_t pos, unsigned len, 1002 struct page *page) 1003 { 1004 struct inode *inode = file_inode(file); 1005 struct ceph_inode_info *ci = ceph_inode(inode); 1006 struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc; 1007 loff_t page_off = pos & PAGE_CACHE_MASK; 1008 int pos_in_page = pos & ~PAGE_CACHE_MASK; 1009 int end_in_page = pos_in_page + len; 1010 loff_t i_size; 1011 int r; 1012 struct ceph_snap_context *snapc, *oldest; 1013 1014 retry_locked: 1015 /* writepages currently holds page lock, but if we change that later, */ 1016 wait_on_page_writeback(page); 1017 1018 /* check snap context */ 1019 BUG_ON(!ci->i_snap_realm); 1020 down_read(&mdsc->snap_rwsem); 1021 BUG_ON(!ci->i_snap_realm->cached_context); 1022 snapc = page_snap_context(page); 1023 if (snapc && snapc != ci->i_head_snapc) { 1024 /* 1025 * this page is already dirty in another (older) snap 1026 * context! is it writeable now? 1027 */ 1028 oldest = get_oldest_context(inode, NULL); 1029 up_read(&mdsc->snap_rwsem); 1030 1031 if (snapc->seq > oldest->seq) { 1032 ceph_put_snap_context(oldest); 1033 dout(" page %p snapc %p not current or oldest\n", 1034 page, snapc); 1035 /* 1036 * queue for writeback, and wait for snapc to 1037 * be writeable or written 1038 */ 1039 snapc = ceph_get_snap_context(snapc); 1040 unlock_page(page); 1041 ceph_queue_writeback(inode); 1042 r = wait_event_interruptible(ci->i_cap_wq, 1043 context_is_writeable_or_written(inode, snapc)); 1044 ceph_put_snap_context(snapc); 1045 if (r == -ERESTARTSYS) 1046 return r; 1047 return -EAGAIN; 1048 } 1049 ceph_put_snap_context(oldest); 1050 1051 /* yay, writeable, do it now (without dropping page lock) */ 1052 dout(" page %p snapc %p not current, but oldest\n", 1053 page, snapc); 1054 if (!clear_page_dirty_for_io(page)) 1055 goto retry_locked; 1056 r = writepage_nounlock(page, NULL); 1057 if (r < 0) 1058 goto fail_nosnap; 1059 goto retry_locked; 1060 } 1061 1062 if (PageUptodate(page)) { 1063 dout(" page %p already uptodate\n", page); 1064 return 0; 1065 } 1066 1067 /* full page? */ 1068 if (pos_in_page == 0 && len == PAGE_CACHE_SIZE) 1069 return 0; 1070 1071 /* past end of file? */ 1072 i_size = inode->i_size; /* caller holds i_mutex */ 1073 1074 if (i_size + len > inode->i_sb->s_maxbytes) { 1075 /* file is too big */ 1076 r = -EINVAL; 1077 goto fail; 1078 } 1079 1080 if (page_off >= i_size || 1081 (pos_in_page == 0 && (pos+len) >= i_size && 1082 end_in_page - pos_in_page != PAGE_CACHE_SIZE)) { 1083 dout(" zeroing %p 0 - %d and %d - %d\n", 1084 page, pos_in_page, end_in_page, (int)PAGE_CACHE_SIZE); 1085 zero_user_segments(page, 1086 0, pos_in_page, 1087 end_in_page, PAGE_CACHE_SIZE); 1088 return 0; 1089 } 1090 1091 /* we need to read it. */ 1092 up_read(&mdsc->snap_rwsem); 1093 r = readpage_nounlock(file, page); 1094 if (r < 0) 1095 goto fail_nosnap; 1096 goto retry_locked; 1097 1098 fail: 1099 up_read(&mdsc->snap_rwsem); 1100 fail_nosnap: 1101 unlock_page(page); 1102 return r; 1103 } 1104 1105 /* 1106 * We are only allowed to write into/dirty the page if the page is 1107 * clean, or already dirty within the same snap context. 1108 */ 1109 static int ceph_write_begin(struct file *file, struct address_space *mapping, 1110 loff_t pos, unsigned len, unsigned flags, 1111 struct page **pagep, void **fsdata) 1112 { 1113 struct inode *inode = file_inode(file); 1114 struct page *page; 1115 pgoff_t index = pos >> PAGE_CACHE_SHIFT; 1116 int r; 1117 1118 do { 1119 /* get a page */ 1120 page = grab_cache_page_write_begin(mapping, index, 0); 1121 if (!page) 1122 return -ENOMEM; 1123 *pagep = page; 1124 1125 dout("write_begin file %p inode %p page %p %d~%d\n", file, 1126 inode, page, (int)pos, (int)len); 1127 1128 r = ceph_update_writeable_page(file, pos, len, page); 1129 } while (r == -EAGAIN); 1130 1131 return r; 1132 } 1133 1134 /* 1135 * we don't do anything in here that simple_write_end doesn't do 1136 * except adjust dirty page accounting and drop read lock on 1137 * mdsc->snap_rwsem. 1138 */ 1139 static int ceph_write_end(struct file *file, struct address_space *mapping, 1140 loff_t pos, unsigned len, unsigned copied, 1141 struct page *page, void *fsdata) 1142 { 1143 struct inode *inode = file_inode(file); 1144 struct ceph_fs_client *fsc = ceph_inode_to_client(inode); 1145 struct ceph_mds_client *mdsc = fsc->mdsc; 1146 unsigned from = pos & (PAGE_CACHE_SIZE - 1); 1147 int check_cap = 0; 1148 1149 dout("write_end file %p inode %p page %p %d~%d (%d)\n", file, 1150 inode, page, (int)pos, (int)copied, (int)len); 1151 1152 /* zero the stale part of the page if we did a short copy */ 1153 if (copied < len) 1154 zero_user_segment(page, from+copied, len); 1155 1156 /* did file size increase? */ 1157 /* (no need for i_size_read(); we caller holds i_mutex */ 1158 if (pos+copied > inode->i_size) 1159 check_cap = ceph_inode_set_size(inode, pos+copied); 1160 1161 if (!PageUptodate(page)) 1162 SetPageUptodate(page); 1163 1164 set_page_dirty(page); 1165 1166 unlock_page(page); 1167 up_read(&mdsc->snap_rwsem); 1168 page_cache_release(page); 1169 1170 if (check_cap) 1171 ceph_check_caps(ceph_inode(inode), CHECK_CAPS_AUTHONLY, NULL); 1172 1173 return copied; 1174 } 1175 1176 /* 1177 * we set .direct_IO to indicate direct io is supported, but since we 1178 * intercept O_DIRECT reads and writes early, this function should 1179 * never get called. 1180 */ 1181 static ssize_t ceph_direct_io(int rw, struct kiocb *iocb, 1182 const struct iovec *iov, 1183 loff_t pos, unsigned long nr_segs) 1184 { 1185 WARN_ON(1); 1186 return -EINVAL; 1187 } 1188 1189 const struct address_space_operations ceph_aops = { 1190 .readpage = ceph_readpage, 1191 .readpages = ceph_readpages, 1192 .writepage = ceph_writepage, 1193 .writepages = ceph_writepages_start, 1194 .write_begin = ceph_write_begin, 1195 .write_end = ceph_write_end, 1196 .set_page_dirty = ceph_set_page_dirty, 1197 .invalidatepage = ceph_invalidatepage, 1198 .releasepage = ceph_releasepage, 1199 .direct_IO = ceph_direct_io, 1200 }; 1201 1202 1203 /* 1204 * vm ops 1205 */ 1206 1207 /* 1208 * Reuse write_begin here for simplicity. 1209 */ 1210 static int ceph_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) 1211 { 1212 struct inode *inode = file_inode(vma->vm_file); 1213 struct page *page = vmf->page; 1214 struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc; 1215 loff_t off = page_offset(page); 1216 loff_t size, len; 1217 int ret; 1218 1219 /* Update time before taking page lock */ 1220 file_update_time(vma->vm_file); 1221 1222 size = i_size_read(inode); 1223 if (off + PAGE_CACHE_SIZE <= size) 1224 len = PAGE_CACHE_SIZE; 1225 else 1226 len = size & ~PAGE_CACHE_MASK; 1227 1228 dout("page_mkwrite %p %llu~%llu page %p idx %lu\n", inode, 1229 off, len, page, page->index); 1230 1231 lock_page(page); 1232 1233 ret = VM_FAULT_NOPAGE; 1234 if ((off > size) || 1235 (page->mapping != inode->i_mapping)) 1236 goto out; 1237 1238 ret = ceph_update_writeable_page(vma->vm_file, off, len, page); 1239 if (ret == 0) { 1240 /* success. we'll keep the page locked. */ 1241 set_page_dirty(page); 1242 up_read(&mdsc->snap_rwsem); 1243 ret = VM_FAULT_LOCKED; 1244 } else { 1245 if (ret == -ENOMEM) 1246 ret = VM_FAULT_OOM; 1247 else 1248 ret = VM_FAULT_SIGBUS; 1249 } 1250 out: 1251 dout("page_mkwrite %p %llu~%llu = %d\n", inode, off, len, ret); 1252 if (ret != VM_FAULT_LOCKED) 1253 unlock_page(page); 1254 return ret; 1255 } 1256 1257 static struct vm_operations_struct ceph_vmops = { 1258 .fault = filemap_fault, 1259 .page_mkwrite = ceph_page_mkwrite, 1260 .remap_pages = generic_file_remap_pages, 1261 }; 1262 1263 int ceph_mmap(struct file *file, struct vm_area_struct *vma) 1264 { 1265 struct address_space *mapping = file->f_mapping; 1266 1267 if (!mapping->a_ops->readpage) 1268 return -ENOEXEC; 1269 file_accessed(file); 1270 vma->vm_ops = &ceph_vmops; 1271 return 0; 1272 } 1273