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 = filp->f_dentry->d_inode; 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_reply_head *replyhead; 240 int rc, bytes; 241 int i; 242 243 /* parse reply */ 244 replyhead = msg->front.iov_base; 245 WARN_ON(le32_to_cpu(replyhead->num_ops) == 0); 246 rc = le32_to_cpu(replyhead->result); 247 bytes = le32_to_cpu(msg->hdr.data_len); 248 249 dout("finish_read %p req %p rc %d bytes %d\n", inode, req, rc, bytes); 250 251 /* unlock all pages, zeroing any data we didn't read */ 252 for (i = 0; i < req->r_num_pages; i++, bytes -= PAGE_CACHE_SIZE) { 253 struct page *page = req->r_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 } 267 kfree(req->r_pages); 268 } 269 270 /* 271 * start an async read(ahead) operation. return nr_pages we submitted 272 * a read for on success, or negative error code. 273 */ 274 static int start_read(struct inode *inode, struct list_head *page_list, int max) 275 { 276 struct ceph_osd_client *osdc = 277 &ceph_inode_to_client(inode)->client->osdc; 278 struct ceph_inode_info *ci = ceph_inode(inode); 279 struct page *page = list_entry(page_list->prev, struct page, lru); 280 struct ceph_osd_request *req; 281 u64 off; 282 u64 len; 283 int i; 284 struct page **pages; 285 pgoff_t next_index; 286 int nr_pages = 0; 287 int ret; 288 289 off = (u64) page_offset(page); 290 291 /* count pages */ 292 next_index = page->index; 293 list_for_each_entry_reverse(page, page_list, lru) { 294 if (page->index != next_index) 295 break; 296 nr_pages++; 297 next_index++; 298 if (max && nr_pages == max) 299 break; 300 } 301 len = nr_pages << PAGE_CACHE_SHIFT; 302 dout("start_read %p nr_pages %d is %lld~%lld\n", inode, nr_pages, 303 off, len); 304 305 req = ceph_osdc_new_request(osdc, &ci->i_layout, ceph_vino(inode), 306 off, &len, 307 CEPH_OSD_OP_READ, CEPH_OSD_FLAG_READ, 308 NULL, 0, 309 ci->i_truncate_seq, ci->i_truncate_size, 310 NULL, false, 1, 0); 311 if (IS_ERR(req)) 312 return PTR_ERR(req); 313 314 /* build page vector */ 315 nr_pages = len >> PAGE_CACHE_SHIFT; 316 pages = kmalloc(sizeof(*pages) * nr_pages, GFP_NOFS); 317 ret = -ENOMEM; 318 if (!pages) 319 goto out; 320 for (i = 0; i < nr_pages; ++i) { 321 page = list_entry(page_list->prev, struct page, lru); 322 BUG_ON(PageLocked(page)); 323 list_del(&page->lru); 324 325 dout("start_read %p adding %p idx %lu\n", inode, page, 326 page->index); 327 if (add_to_page_cache_lru(page, &inode->i_data, page->index, 328 GFP_NOFS)) { 329 page_cache_release(page); 330 dout("start_read %p add_to_page_cache failed %p\n", 331 inode, page); 332 nr_pages = i; 333 goto out_pages; 334 } 335 pages[i] = page; 336 } 337 req->r_pages = pages; 338 req->r_num_pages = nr_pages; 339 req->r_callback = finish_read; 340 req->r_inode = inode; 341 342 dout("start_read %p starting %p %lld~%lld\n", inode, req, off, len); 343 ret = ceph_osdc_start_request(osdc, req, false); 344 if (ret < 0) 345 goto out_pages; 346 ceph_osdc_put_request(req); 347 return nr_pages; 348 349 out_pages: 350 ceph_release_page_vector(pages, nr_pages); 351 out: 352 ceph_osdc_put_request(req); 353 return ret; 354 } 355 356 357 /* 358 * Read multiple pages. Leave pages we don't read + unlock in page_list; 359 * the caller (VM) cleans them up. 360 */ 361 static int ceph_readpages(struct file *file, struct address_space *mapping, 362 struct list_head *page_list, unsigned nr_pages) 363 { 364 struct inode *inode = file->f_dentry->d_inode; 365 struct ceph_fs_client *fsc = ceph_inode_to_client(inode); 366 int rc = 0; 367 int max = 0; 368 369 if (fsc->mount_options->rsize >= PAGE_CACHE_SIZE) 370 max = (fsc->mount_options->rsize + PAGE_CACHE_SIZE - 1) 371 >> PAGE_SHIFT; 372 373 dout("readpages %p file %p nr_pages %d max %d\n", inode, file, nr_pages, 374 max); 375 while (!list_empty(page_list)) { 376 rc = start_read(inode, page_list, max); 377 if (rc < 0) 378 goto out; 379 BUG_ON(rc == 0); 380 } 381 out: 382 dout("readpages %p file %p ret %d\n", inode, file, rc); 383 return rc; 384 } 385 386 /* 387 * Get ref for the oldest snapc for an inode with dirty data... that is, the 388 * only snap context we are allowed to write back. 389 */ 390 static struct ceph_snap_context *get_oldest_context(struct inode *inode, 391 u64 *snap_size) 392 { 393 struct ceph_inode_info *ci = ceph_inode(inode); 394 struct ceph_snap_context *snapc = NULL; 395 struct ceph_cap_snap *capsnap = NULL; 396 397 spin_lock(&ci->i_ceph_lock); 398 list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) { 399 dout(" cap_snap %p snapc %p has %d dirty pages\n", capsnap, 400 capsnap->context, capsnap->dirty_pages); 401 if (capsnap->dirty_pages) { 402 snapc = ceph_get_snap_context(capsnap->context); 403 if (snap_size) 404 *snap_size = capsnap->size; 405 break; 406 } 407 } 408 if (!snapc && ci->i_wrbuffer_ref_head) { 409 snapc = ceph_get_snap_context(ci->i_head_snapc); 410 dout(" head snapc %p has %d dirty pages\n", 411 snapc, ci->i_wrbuffer_ref_head); 412 } 413 spin_unlock(&ci->i_ceph_lock); 414 return snapc; 415 } 416 417 /* 418 * Write a single page, but leave the page locked. 419 * 420 * If we get a write error, set the page error bit, but still adjust the 421 * dirty page accounting (i.e., page is no longer dirty). 422 */ 423 static int writepage_nounlock(struct page *page, struct writeback_control *wbc) 424 { 425 struct inode *inode; 426 struct ceph_inode_info *ci; 427 struct ceph_fs_client *fsc; 428 struct ceph_osd_client *osdc; 429 loff_t page_off = page_offset(page); 430 int len = PAGE_CACHE_SIZE; 431 loff_t i_size; 432 int err = 0; 433 struct ceph_snap_context *snapc, *oldest; 434 u64 snap_size = 0; 435 long writeback_stat; 436 437 dout("writepage %p idx %lu\n", page, page->index); 438 439 if (!page->mapping || !page->mapping->host) { 440 dout("writepage %p - no mapping\n", page); 441 return -EFAULT; 442 } 443 inode = page->mapping->host; 444 ci = ceph_inode(inode); 445 fsc = ceph_inode_to_client(inode); 446 osdc = &fsc->client->osdc; 447 448 /* verify this is a writeable snap context */ 449 snapc = page_snap_context(page); 450 if (snapc == NULL) { 451 dout("writepage %p page %p not dirty?\n", inode, page); 452 goto out; 453 } 454 oldest = get_oldest_context(inode, &snap_size); 455 if (snapc->seq > oldest->seq) { 456 dout("writepage %p page %p snapc %p not writeable - noop\n", 457 inode, page, snapc); 458 /* we should only noop if called by kswapd */ 459 WARN_ON((current->flags & PF_MEMALLOC) == 0); 460 ceph_put_snap_context(oldest); 461 goto out; 462 } 463 ceph_put_snap_context(oldest); 464 465 /* is this a partial page at end of file? */ 466 if (snap_size) 467 i_size = snap_size; 468 else 469 i_size = i_size_read(inode); 470 if (i_size < page_off + len) 471 len = i_size - page_off; 472 473 dout("writepage %p page %p index %lu on %llu~%u snapc %p\n", 474 inode, page, page->index, page_off, len, snapc); 475 476 writeback_stat = atomic_long_inc_return(&fsc->writeback_count); 477 if (writeback_stat > 478 CONGESTION_ON_THRESH(fsc->mount_options->congestion_kb)) 479 set_bdi_congested(&fsc->backing_dev_info, BLK_RW_ASYNC); 480 481 set_page_writeback(page); 482 err = ceph_osdc_writepages(osdc, ceph_vino(inode), 483 &ci->i_layout, snapc, 484 page_off, len, 485 ci->i_truncate_seq, ci->i_truncate_size, 486 &inode->i_mtime, 487 &page, 1, 0, 0, true); 488 if (err < 0) { 489 dout("writepage setting page/mapping error %d %p\n", err, page); 490 SetPageError(page); 491 mapping_set_error(&inode->i_data, err); 492 if (wbc) 493 wbc->pages_skipped++; 494 } else { 495 dout("writepage cleaned page %p\n", page); 496 err = 0; /* vfs expects us to return 0 */ 497 } 498 page->private = 0; 499 ClearPagePrivate(page); 500 end_page_writeback(page); 501 ceph_put_wrbuffer_cap_refs(ci, 1, snapc); 502 ceph_put_snap_context(snapc); /* page's reference */ 503 out: 504 return err; 505 } 506 507 static int ceph_writepage(struct page *page, struct writeback_control *wbc) 508 { 509 int err; 510 struct inode *inode = page->mapping->host; 511 BUG_ON(!inode); 512 ihold(inode); 513 err = writepage_nounlock(page, wbc); 514 unlock_page(page); 515 iput(inode); 516 return err; 517 } 518 519 520 /* 521 * lame release_pages helper. release_pages() isn't exported to 522 * modules. 523 */ 524 static void ceph_release_pages(struct page **pages, int num) 525 { 526 struct pagevec pvec; 527 int i; 528 529 pagevec_init(&pvec, 0); 530 for (i = 0; i < num; i++) { 531 if (pagevec_add(&pvec, pages[i]) == 0) 532 pagevec_release(&pvec); 533 } 534 pagevec_release(&pvec); 535 } 536 537 538 /* 539 * async writeback completion handler. 540 * 541 * If we get an error, set the mapping error bit, but not the individual 542 * page error bits. 543 */ 544 static void writepages_finish(struct ceph_osd_request *req, 545 struct ceph_msg *msg) 546 { 547 struct inode *inode = req->r_inode; 548 struct ceph_osd_reply_head *replyhead; 549 struct ceph_osd_op *op; 550 struct ceph_inode_info *ci = ceph_inode(inode); 551 unsigned wrote; 552 struct page *page; 553 int i; 554 struct ceph_snap_context *snapc = req->r_snapc; 555 struct address_space *mapping = inode->i_mapping; 556 __s32 rc = -EIO; 557 u64 bytes = 0; 558 struct ceph_fs_client *fsc = ceph_inode_to_client(inode); 559 long writeback_stat; 560 unsigned issued = ceph_caps_issued(ci); 561 562 /* parse reply */ 563 replyhead = msg->front.iov_base; 564 WARN_ON(le32_to_cpu(replyhead->num_ops) == 0); 565 op = (void *)(replyhead + 1); 566 rc = le32_to_cpu(replyhead->result); 567 bytes = le64_to_cpu(op->extent.length); 568 569 if (rc >= 0) { 570 /* 571 * Assume we wrote the pages we originally sent. The 572 * osd might reply with fewer pages if our writeback 573 * raced with a truncation and was adjusted at the osd, 574 * so don't believe the reply. 575 */ 576 wrote = req->r_num_pages; 577 } else { 578 wrote = 0; 579 mapping_set_error(mapping, rc); 580 } 581 dout("writepages_finish %p rc %d bytes %llu wrote %d (pages)\n", 582 inode, rc, bytes, wrote); 583 584 /* clean all pages */ 585 for (i = 0; i < req->r_num_pages; i++) { 586 page = req->r_pages[i]; 587 BUG_ON(!page); 588 WARN_ON(!PageUptodate(page)); 589 590 writeback_stat = 591 atomic_long_dec_return(&fsc->writeback_count); 592 if (writeback_stat < 593 CONGESTION_OFF_THRESH(fsc->mount_options->congestion_kb)) 594 clear_bdi_congested(&fsc->backing_dev_info, 595 BLK_RW_ASYNC); 596 597 ceph_put_snap_context(page_snap_context(page)); 598 page->private = 0; 599 ClearPagePrivate(page); 600 dout("unlocking %d %p\n", i, page); 601 end_page_writeback(page); 602 603 /* 604 * We lost the cache cap, need to truncate the page before 605 * it is unlocked, otherwise we'd truncate it later in the 606 * page truncation thread, possibly losing some data that 607 * raced its way in 608 */ 609 if ((issued & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) == 0) 610 generic_error_remove_page(inode->i_mapping, page); 611 612 unlock_page(page); 613 } 614 dout("%p wrote+cleaned %d pages\n", inode, wrote); 615 ceph_put_wrbuffer_cap_refs(ci, req->r_num_pages, snapc); 616 617 ceph_release_pages(req->r_pages, req->r_num_pages); 618 if (req->r_pages_from_pool) 619 mempool_free(req->r_pages, 620 ceph_sb_to_client(inode->i_sb)->wb_pagevec_pool); 621 else 622 kfree(req->r_pages); 623 ceph_osdc_put_request(req); 624 } 625 626 /* 627 * allocate a page vec, either directly, or if necessary, via a the 628 * mempool. we avoid the mempool if we can because req->r_num_pages 629 * may be less than the maximum write size. 630 */ 631 static void alloc_page_vec(struct ceph_fs_client *fsc, 632 struct ceph_osd_request *req) 633 { 634 req->r_pages = kmalloc(sizeof(struct page *) * req->r_num_pages, 635 GFP_NOFS); 636 if (!req->r_pages) { 637 req->r_pages = mempool_alloc(fsc->wb_pagevec_pool, GFP_NOFS); 638 req->r_pages_from_pool = 1; 639 WARN_ON(!req->r_pages); 640 } 641 } 642 643 /* 644 * initiate async writeback 645 */ 646 static int ceph_writepages_start(struct address_space *mapping, 647 struct writeback_control *wbc) 648 { 649 struct inode *inode = mapping->host; 650 struct ceph_inode_info *ci = ceph_inode(inode); 651 struct ceph_fs_client *fsc; 652 pgoff_t index, start, end; 653 int range_whole = 0; 654 int should_loop = 1; 655 pgoff_t max_pages = 0, max_pages_ever = 0; 656 struct ceph_snap_context *snapc = NULL, *last_snapc = NULL, *pgsnapc; 657 struct pagevec pvec; 658 int done = 0; 659 int rc = 0; 660 unsigned wsize = 1 << inode->i_blkbits; 661 struct ceph_osd_request *req = NULL; 662 int do_sync; 663 u64 snap_size = 0; 664 665 /* 666 * Include a 'sync' in the OSD request if this is a data 667 * integrity write (e.g., O_SYNC write or fsync()), or if our 668 * cap is being revoked. 669 */ 670 do_sync = wbc->sync_mode == WB_SYNC_ALL; 671 if (ceph_caps_revoking(ci, CEPH_CAP_FILE_BUFFER)) 672 do_sync = 1; 673 dout("writepages_start %p dosync=%d (mode=%s)\n", 674 inode, do_sync, 675 wbc->sync_mode == WB_SYNC_NONE ? "NONE" : 676 (wbc->sync_mode == WB_SYNC_ALL ? "ALL" : "HOLD")); 677 678 fsc = ceph_inode_to_client(inode); 679 if (fsc->mount_state == CEPH_MOUNT_SHUTDOWN) { 680 pr_warning("writepage_start %p on forced umount\n", inode); 681 return -EIO; /* we're in a forced umount, don't write! */ 682 } 683 if (fsc->mount_options->wsize && fsc->mount_options->wsize < wsize) 684 wsize = fsc->mount_options->wsize; 685 if (wsize < PAGE_CACHE_SIZE) 686 wsize = PAGE_CACHE_SIZE; 687 max_pages_ever = wsize >> PAGE_CACHE_SHIFT; 688 689 pagevec_init(&pvec, 0); 690 691 /* where to start/end? */ 692 if (wbc->range_cyclic) { 693 start = mapping->writeback_index; /* Start from prev offset */ 694 end = -1; 695 dout(" cyclic, start at %lu\n", start); 696 } else { 697 start = wbc->range_start >> PAGE_CACHE_SHIFT; 698 end = wbc->range_end >> PAGE_CACHE_SHIFT; 699 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) 700 range_whole = 1; 701 should_loop = 0; 702 dout(" not cyclic, %lu to %lu\n", start, end); 703 } 704 index = start; 705 706 retry: 707 /* find oldest snap context with dirty data */ 708 ceph_put_snap_context(snapc); 709 snapc = get_oldest_context(inode, &snap_size); 710 if (!snapc) { 711 /* hmm, why does writepages get called when there 712 is no dirty data? */ 713 dout(" no snap context with dirty data?\n"); 714 goto out; 715 } 716 dout(" oldest snapc is %p seq %lld (%d snaps)\n", 717 snapc, snapc->seq, snapc->num_snaps); 718 if (last_snapc && snapc != last_snapc) { 719 /* if we switched to a newer snapc, restart our scan at the 720 * start of the original file range. */ 721 dout(" snapc differs from last pass, restarting at %lu\n", 722 index); 723 index = start; 724 } 725 last_snapc = snapc; 726 727 while (!done && index <= end) { 728 unsigned i; 729 int first; 730 pgoff_t next; 731 int pvec_pages, locked_pages; 732 struct page *page; 733 int want; 734 u64 offset, len; 735 struct ceph_osd_request_head *reqhead; 736 struct ceph_osd_op *op; 737 long writeback_stat; 738 739 next = 0; 740 locked_pages = 0; 741 max_pages = max_pages_ever; 742 743 get_more_pages: 744 first = -1; 745 want = min(end - index, 746 min((pgoff_t)PAGEVEC_SIZE, 747 max_pages - (pgoff_t)locked_pages) - 1) 748 + 1; 749 pvec_pages = pagevec_lookup_tag(&pvec, mapping, &index, 750 PAGECACHE_TAG_DIRTY, 751 want); 752 dout("pagevec_lookup_tag got %d\n", pvec_pages); 753 if (!pvec_pages && !locked_pages) 754 break; 755 for (i = 0; i < pvec_pages && locked_pages < max_pages; i++) { 756 page = pvec.pages[i]; 757 dout("? %p idx %lu\n", page, page->index); 758 if (locked_pages == 0) 759 lock_page(page); /* first page */ 760 else if (!trylock_page(page)) 761 break; 762 763 /* only dirty pages, or our accounting breaks */ 764 if (unlikely(!PageDirty(page)) || 765 unlikely(page->mapping != mapping)) { 766 dout("!dirty or !mapping %p\n", page); 767 unlock_page(page); 768 break; 769 } 770 if (!wbc->range_cyclic && page->index > end) { 771 dout("end of range %p\n", page); 772 done = 1; 773 unlock_page(page); 774 break; 775 } 776 if (next && (page->index != next)) { 777 dout("not consecutive %p\n", page); 778 unlock_page(page); 779 break; 780 } 781 if (wbc->sync_mode != WB_SYNC_NONE) { 782 dout("waiting on writeback %p\n", page); 783 wait_on_page_writeback(page); 784 } 785 if ((snap_size && page_offset(page) > snap_size) || 786 (!snap_size && 787 page_offset(page) > i_size_read(inode))) { 788 dout("%p page eof %llu\n", page, snap_size ? 789 snap_size : i_size_read(inode)); 790 done = 1; 791 unlock_page(page); 792 break; 793 } 794 if (PageWriteback(page)) { 795 dout("%p under writeback\n", page); 796 unlock_page(page); 797 break; 798 } 799 800 /* only if matching snap context */ 801 pgsnapc = page_snap_context(page); 802 if (pgsnapc->seq > snapc->seq) { 803 dout("page snapc %p %lld > oldest %p %lld\n", 804 pgsnapc, pgsnapc->seq, snapc, snapc->seq); 805 unlock_page(page); 806 if (!locked_pages) 807 continue; /* keep looking for snap */ 808 break; 809 } 810 811 if (!clear_page_dirty_for_io(page)) { 812 dout("%p !clear_page_dirty_for_io\n", page); 813 unlock_page(page); 814 break; 815 } 816 817 /* ok */ 818 if (locked_pages == 0) { 819 /* prepare async write request */ 820 offset = (u64) page_offset(page); 821 len = wsize; 822 req = ceph_osdc_new_request(&fsc->client->osdc, 823 &ci->i_layout, 824 ceph_vino(inode), 825 offset, &len, 826 CEPH_OSD_OP_WRITE, 827 CEPH_OSD_FLAG_WRITE | 828 CEPH_OSD_FLAG_ONDISK, 829 snapc, do_sync, 830 ci->i_truncate_seq, 831 ci->i_truncate_size, 832 &inode->i_mtime, true, 1, 0); 833 834 if (IS_ERR(req)) { 835 rc = PTR_ERR(req); 836 unlock_page(page); 837 break; 838 } 839 840 max_pages = req->r_num_pages; 841 842 alloc_page_vec(fsc, req); 843 req->r_callback = writepages_finish; 844 req->r_inode = inode; 845 } 846 847 /* note position of first page in pvec */ 848 if (first < 0) 849 first = i; 850 dout("%p will write page %p idx %lu\n", 851 inode, page, page->index); 852 853 writeback_stat = 854 atomic_long_inc_return(&fsc->writeback_count); 855 if (writeback_stat > CONGESTION_ON_THRESH( 856 fsc->mount_options->congestion_kb)) { 857 set_bdi_congested(&fsc->backing_dev_info, 858 BLK_RW_ASYNC); 859 } 860 861 set_page_writeback(page); 862 req->r_pages[locked_pages] = page; 863 locked_pages++; 864 next = page->index + 1; 865 } 866 867 /* did we get anything? */ 868 if (!locked_pages) 869 goto release_pvec_pages; 870 if (i) { 871 int j; 872 BUG_ON(!locked_pages || first < 0); 873 874 if (pvec_pages && i == pvec_pages && 875 locked_pages < max_pages) { 876 dout("reached end pvec, trying for more\n"); 877 pagevec_reinit(&pvec); 878 goto get_more_pages; 879 } 880 881 /* shift unused pages over in the pvec... we 882 * will need to release them below. */ 883 for (j = i; j < pvec_pages; j++) { 884 dout(" pvec leftover page %p\n", 885 pvec.pages[j]); 886 pvec.pages[j-i+first] = pvec.pages[j]; 887 } 888 pvec.nr -= i-first; 889 } 890 891 /* submit the write */ 892 offset = req->r_pages[0]->index << PAGE_CACHE_SHIFT; 893 len = min((snap_size ? snap_size : i_size_read(inode)) - offset, 894 (u64)locked_pages << PAGE_CACHE_SHIFT); 895 dout("writepages got %d pages at %llu~%llu\n", 896 locked_pages, offset, len); 897 898 /* revise final length, page count */ 899 req->r_num_pages = locked_pages; 900 reqhead = req->r_request->front.iov_base; 901 op = (void *)(reqhead + 1); 902 op->extent.length = cpu_to_le64(len); 903 op->payload_len = cpu_to_le32(len); 904 req->r_request->hdr.data_len = cpu_to_le32(len); 905 906 rc = ceph_osdc_start_request(&fsc->client->osdc, req, true); 907 BUG_ON(rc); 908 req = NULL; 909 910 /* continue? */ 911 index = next; 912 wbc->nr_to_write -= locked_pages; 913 if (wbc->nr_to_write <= 0) 914 done = 1; 915 916 release_pvec_pages: 917 dout("pagevec_release on %d pages (%p)\n", (int)pvec.nr, 918 pvec.nr ? pvec.pages[0] : NULL); 919 pagevec_release(&pvec); 920 921 if (locked_pages && !done) 922 goto retry; 923 } 924 925 if (should_loop && !done) { 926 /* more to do; loop back to beginning of file */ 927 dout("writepages looping back to beginning of file\n"); 928 should_loop = 0; 929 index = 0; 930 goto retry; 931 } 932 933 if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0)) 934 mapping->writeback_index = index; 935 936 out: 937 if (req) 938 ceph_osdc_put_request(req); 939 ceph_put_snap_context(snapc); 940 dout("writepages done, rc = %d\n", rc); 941 return rc; 942 } 943 944 945 946 /* 947 * See if a given @snapc is either writeable, or already written. 948 */ 949 static int context_is_writeable_or_written(struct inode *inode, 950 struct ceph_snap_context *snapc) 951 { 952 struct ceph_snap_context *oldest = get_oldest_context(inode, NULL); 953 int ret = !oldest || snapc->seq <= oldest->seq; 954 955 ceph_put_snap_context(oldest); 956 return ret; 957 } 958 959 /* 960 * We are only allowed to write into/dirty the page if the page is 961 * clean, or already dirty within the same snap context. 962 * 963 * called with page locked. 964 * return success with page locked, 965 * or any failure (incl -EAGAIN) with page unlocked. 966 */ 967 static int ceph_update_writeable_page(struct file *file, 968 loff_t pos, unsigned len, 969 struct page *page) 970 { 971 struct inode *inode = file->f_dentry->d_inode; 972 struct ceph_inode_info *ci = ceph_inode(inode); 973 struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc; 974 loff_t page_off = pos & PAGE_CACHE_MASK; 975 int pos_in_page = pos & ~PAGE_CACHE_MASK; 976 int end_in_page = pos_in_page + len; 977 loff_t i_size; 978 int r; 979 struct ceph_snap_context *snapc, *oldest; 980 981 retry_locked: 982 /* writepages currently holds page lock, but if we change that later, */ 983 wait_on_page_writeback(page); 984 985 /* check snap context */ 986 BUG_ON(!ci->i_snap_realm); 987 down_read(&mdsc->snap_rwsem); 988 BUG_ON(!ci->i_snap_realm->cached_context); 989 snapc = page_snap_context(page); 990 if (snapc && snapc != ci->i_head_snapc) { 991 /* 992 * this page is already dirty in another (older) snap 993 * context! is it writeable now? 994 */ 995 oldest = get_oldest_context(inode, NULL); 996 up_read(&mdsc->snap_rwsem); 997 998 if (snapc->seq > oldest->seq) { 999 ceph_put_snap_context(oldest); 1000 dout(" page %p snapc %p not current or oldest\n", 1001 page, snapc); 1002 /* 1003 * queue for writeback, and wait for snapc to 1004 * be writeable or written 1005 */ 1006 snapc = ceph_get_snap_context(snapc); 1007 unlock_page(page); 1008 ceph_queue_writeback(inode); 1009 r = wait_event_interruptible(ci->i_cap_wq, 1010 context_is_writeable_or_written(inode, snapc)); 1011 ceph_put_snap_context(snapc); 1012 if (r == -ERESTARTSYS) 1013 return r; 1014 return -EAGAIN; 1015 } 1016 ceph_put_snap_context(oldest); 1017 1018 /* yay, writeable, do it now (without dropping page lock) */ 1019 dout(" page %p snapc %p not current, but oldest\n", 1020 page, snapc); 1021 if (!clear_page_dirty_for_io(page)) 1022 goto retry_locked; 1023 r = writepage_nounlock(page, NULL); 1024 if (r < 0) 1025 goto fail_nosnap; 1026 goto retry_locked; 1027 } 1028 1029 if (PageUptodate(page)) { 1030 dout(" page %p already uptodate\n", page); 1031 return 0; 1032 } 1033 1034 /* full page? */ 1035 if (pos_in_page == 0 && len == PAGE_CACHE_SIZE) 1036 return 0; 1037 1038 /* past end of file? */ 1039 i_size = inode->i_size; /* caller holds i_mutex */ 1040 1041 if (i_size + len > inode->i_sb->s_maxbytes) { 1042 /* file is too big */ 1043 r = -EINVAL; 1044 goto fail; 1045 } 1046 1047 if (page_off >= i_size || 1048 (pos_in_page == 0 && (pos+len) >= i_size && 1049 end_in_page - pos_in_page != PAGE_CACHE_SIZE)) { 1050 dout(" zeroing %p 0 - %d and %d - %d\n", 1051 page, pos_in_page, end_in_page, (int)PAGE_CACHE_SIZE); 1052 zero_user_segments(page, 1053 0, pos_in_page, 1054 end_in_page, PAGE_CACHE_SIZE); 1055 return 0; 1056 } 1057 1058 /* we need to read it. */ 1059 up_read(&mdsc->snap_rwsem); 1060 r = readpage_nounlock(file, page); 1061 if (r < 0) 1062 goto fail_nosnap; 1063 goto retry_locked; 1064 1065 fail: 1066 up_read(&mdsc->snap_rwsem); 1067 fail_nosnap: 1068 unlock_page(page); 1069 return r; 1070 } 1071 1072 /* 1073 * We are only allowed to write into/dirty the page if the page is 1074 * clean, or already dirty within the same snap context. 1075 */ 1076 static int ceph_write_begin(struct file *file, struct address_space *mapping, 1077 loff_t pos, unsigned len, unsigned flags, 1078 struct page **pagep, void **fsdata) 1079 { 1080 struct inode *inode = file->f_dentry->d_inode; 1081 struct page *page; 1082 pgoff_t index = pos >> PAGE_CACHE_SHIFT; 1083 int r; 1084 1085 do { 1086 /* get a page */ 1087 page = grab_cache_page_write_begin(mapping, index, 0); 1088 if (!page) 1089 return -ENOMEM; 1090 *pagep = page; 1091 1092 dout("write_begin file %p inode %p page %p %d~%d\n", file, 1093 inode, page, (int)pos, (int)len); 1094 1095 r = ceph_update_writeable_page(file, pos, len, page); 1096 } while (r == -EAGAIN); 1097 1098 return r; 1099 } 1100 1101 /* 1102 * we don't do anything in here that simple_write_end doesn't do 1103 * except adjust dirty page accounting and drop read lock on 1104 * mdsc->snap_rwsem. 1105 */ 1106 static int ceph_write_end(struct file *file, struct address_space *mapping, 1107 loff_t pos, unsigned len, unsigned copied, 1108 struct page *page, void *fsdata) 1109 { 1110 struct inode *inode = file->f_dentry->d_inode; 1111 struct ceph_fs_client *fsc = ceph_inode_to_client(inode); 1112 struct ceph_mds_client *mdsc = fsc->mdsc; 1113 unsigned from = pos & (PAGE_CACHE_SIZE - 1); 1114 int check_cap = 0; 1115 1116 dout("write_end file %p inode %p page %p %d~%d (%d)\n", file, 1117 inode, page, (int)pos, (int)copied, (int)len); 1118 1119 /* zero the stale part of the page if we did a short copy */ 1120 if (copied < len) 1121 zero_user_segment(page, from+copied, len); 1122 1123 /* did file size increase? */ 1124 /* (no need for i_size_read(); we caller holds i_mutex */ 1125 if (pos+copied > inode->i_size) 1126 check_cap = ceph_inode_set_size(inode, pos+copied); 1127 1128 if (!PageUptodate(page)) 1129 SetPageUptodate(page); 1130 1131 set_page_dirty(page); 1132 1133 unlock_page(page); 1134 up_read(&mdsc->snap_rwsem); 1135 page_cache_release(page); 1136 1137 if (check_cap) 1138 ceph_check_caps(ceph_inode(inode), CHECK_CAPS_AUTHONLY, NULL); 1139 1140 return copied; 1141 } 1142 1143 /* 1144 * we set .direct_IO to indicate direct io is supported, but since we 1145 * intercept O_DIRECT reads and writes early, this function should 1146 * never get called. 1147 */ 1148 static ssize_t ceph_direct_io(int rw, struct kiocb *iocb, 1149 const struct iovec *iov, 1150 loff_t pos, unsigned long nr_segs) 1151 { 1152 WARN_ON(1); 1153 return -EINVAL; 1154 } 1155 1156 const struct address_space_operations ceph_aops = { 1157 .readpage = ceph_readpage, 1158 .readpages = ceph_readpages, 1159 .writepage = ceph_writepage, 1160 .writepages = ceph_writepages_start, 1161 .write_begin = ceph_write_begin, 1162 .write_end = ceph_write_end, 1163 .set_page_dirty = ceph_set_page_dirty, 1164 .invalidatepage = ceph_invalidatepage, 1165 .releasepage = ceph_releasepage, 1166 .direct_IO = ceph_direct_io, 1167 }; 1168 1169 1170 /* 1171 * vm ops 1172 */ 1173 1174 /* 1175 * Reuse write_begin here for simplicity. 1176 */ 1177 static int ceph_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) 1178 { 1179 struct inode *inode = vma->vm_file->f_dentry->d_inode; 1180 struct page *page = vmf->page; 1181 struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc; 1182 loff_t off = page_offset(page); 1183 loff_t size, len; 1184 int ret; 1185 1186 /* Update time before taking page lock */ 1187 file_update_time(vma->vm_file); 1188 1189 size = i_size_read(inode); 1190 if (off + PAGE_CACHE_SIZE <= size) 1191 len = PAGE_CACHE_SIZE; 1192 else 1193 len = size & ~PAGE_CACHE_MASK; 1194 1195 dout("page_mkwrite %p %llu~%llu page %p idx %lu\n", inode, 1196 off, len, page, page->index); 1197 1198 lock_page(page); 1199 1200 ret = VM_FAULT_NOPAGE; 1201 if ((off > size) || 1202 (page->mapping != inode->i_mapping)) 1203 goto out; 1204 1205 ret = ceph_update_writeable_page(vma->vm_file, off, len, page); 1206 if (ret == 0) { 1207 /* success. we'll keep the page locked. */ 1208 set_page_dirty(page); 1209 up_read(&mdsc->snap_rwsem); 1210 ret = VM_FAULT_LOCKED; 1211 } else { 1212 if (ret == -ENOMEM) 1213 ret = VM_FAULT_OOM; 1214 else 1215 ret = VM_FAULT_SIGBUS; 1216 } 1217 out: 1218 dout("page_mkwrite %p %llu~%llu = %d\n", inode, off, len, ret); 1219 if (ret != VM_FAULT_LOCKED) 1220 unlock_page(page); 1221 return ret; 1222 } 1223 1224 static struct vm_operations_struct ceph_vmops = { 1225 .fault = filemap_fault, 1226 .page_mkwrite = ceph_page_mkwrite, 1227 .remap_pages = generic_file_remap_pages, 1228 }; 1229 1230 int ceph_mmap(struct file *file, struct vm_area_struct *vma) 1231 { 1232 struct address_space *mapping = file->f_mapping; 1233 1234 if (!mapping->a_ops->readpage) 1235 return -ENOEXEC; 1236 file_accessed(file); 1237 vma->vm_ops = &ceph_vmops; 1238 return 0; 1239 } 1240