1 /* 2 * linux/fs/nfs/direct.c 3 * 4 * Copyright (C) 2003 by Chuck Lever <cel@netapp.com> 5 * 6 * High-performance uncached I/O for the Linux NFS client 7 * 8 * There are important applications whose performance or correctness 9 * depends on uncached access to file data. Database clusters 10 * (multiple copies of the same instance running on separate hosts) 11 * implement their own cache coherency protocol that subsumes file 12 * system cache protocols. Applications that process datasets 13 * considerably larger than the client's memory do not always benefit 14 * from a local cache. A streaming video server, for instance, has no 15 * need to cache the contents of a file. 16 * 17 * When an application requests uncached I/O, all read and write requests 18 * are made directly to the server; data stored or fetched via these 19 * requests is not cached in the Linux page cache. The client does not 20 * correct unaligned requests from applications. All requested bytes are 21 * held on permanent storage before a direct write system call returns to 22 * an application. 23 * 24 * Solaris implements an uncached I/O facility called directio() that 25 * is used for backups and sequential I/O to very large files. Solaris 26 * also supports uncaching whole NFS partitions with "-o forcedirectio," 27 * an undocumented mount option. 28 * 29 * Designed by Jeff Kimmel, Chuck Lever, and Trond Myklebust, with 30 * help from Andrew Morton. 31 * 32 * 18 Dec 2001 Initial implementation for 2.4 --cel 33 * 08 Jul 2002 Version for 2.4.19, with bug fixes --trondmy 34 * 08 Jun 2003 Port to 2.5 APIs --cel 35 * 31 Mar 2004 Handle direct I/O without VFS support --cel 36 * 15 Sep 2004 Parallel async reads --cel 37 * 04 May 2005 support O_DIRECT with aio --cel 38 * 39 */ 40 41 #include <linux/errno.h> 42 #include <linux/sched.h> 43 #include <linux/kernel.h> 44 #include <linux/file.h> 45 #include <linux/pagemap.h> 46 #include <linux/kref.h> 47 #include <linux/slab.h> 48 #include <linux/task_io_accounting_ops.h> 49 #include <linux/module.h> 50 51 #include <linux/nfs_fs.h> 52 #include <linux/nfs_page.h> 53 #include <linux/sunrpc/clnt.h> 54 55 #include <asm/uaccess.h> 56 #include <linux/atomic.h> 57 58 #include "internal.h" 59 #include "iostat.h" 60 #include "pnfs.h" 61 62 #define NFSDBG_FACILITY NFSDBG_VFS 63 64 static struct kmem_cache *nfs_direct_cachep; 65 66 /* 67 * This represents a set of asynchronous requests that we're waiting on 68 */ 69 struct nfs_direct_mirror { 70 ssize_t count; 71 }; 72 73 struct nfs_direct_req { 74 struct kref kref; /* release manager */ 75 76 /* I/O parameters */ 77 struct nfs_open_context *ctx; /* file open context info */ 78 struct nfs_lock_context *l_ctx; /* Lock context info */ 79 struct kiocb * iocb; /* controlling i/o request */ 80 struct inode * inode; /* target file of i/o */ 81 82 /* completion state */ 83 atomic_t io_count; /* i/os we're waiting for */ 84 spinlock_t lock; /* protect completion state */ 85 86 struct nfs_direct_mirror mirrors[NFS_PAGEIO_DESCRIPTOR_MIRROR_MAX]; 87 int mirror_count; 88 89 ssize_t count, /* bytes actually processed */ 90 bytes_left, /* bytes left to be sent */ 91 io_start, /* start of IO */ 92 error; /* any reported error */ 93 struct completion completion; /* wait for i/o completion */ 94 95 /* commit state */ 96 struct nfs_mds_commit_info mds_cinfo; /* Storage for cinfo */ 97 struct pnfs_ds_commit_info ds_cinfo; /* Storage for cinfo */ 98 struct work_struct work; 99 int flags; 100 #define NFS_ODIRECT_DO_COMMIT (1) /* an unstable reply was received */ 101 #define NFS_ODIRECT_RESCHED_WRITES (2) /* write verification failed */ 102 struct nfs_writeverf verf; /* unstable write verifier */ 103 }; 104 105 static const struct nfs_pgio_completion_ops nfs_direct_write_completion_ops; 106 static const struct nfs_commit_completion_ops nfs_direct_commit_completion_ops; 107 static void nfs_direct_write_complete(struct nfs_direct_req *dreq, struct inode *inode); 108 static void nfs_direct_write_schedule_work(struct work_struct *work); 109 110 static inline void get_dreq(struct nfs_direct_req *dreq) 111 { 112 atomic_inc(&dreq->io_count); 113 } 114 115 static inline int put_dreq(struct nfs_direct_req *dreq) 116 { 117 return atomic_dec_and_test(&dreq->io_count); 118 } 119 120 void nfs_direct_set_resched_writes(struct nfs_direct_req *dreq) 121 { 122 dreq->flags = NFS_ODIRECT_RESCHED_WRITES; 123 } 124 EXPORT_SYMBOL_GPL(nfs_direct_set_resched_writes); 125 126 static void 127 nfs_direct_good_bytes(struct nfs_direct_req *dreq, struct nfs_pgio_header *hdr) 128 { 129 int i; 130 ssize_t count; 131 132 WARN_ON_ONCE(hdr->pgio_mirror_idx >= dreq->mirror_count); 133 134 count = dreq->mirrors[hdr->pgio_mirror_idx].count; 135 if (count + dreq->io_start < hdr->io_start + hdr->good_bytes) { 136 count = hdr->io_start + hdr->good_bytes - dreq->io_start; 137 dreq->mirrors[hdr->pgio_mirror_idx].count = count; 138 } 139 140 /* update the dreq->count by finding the minimum agreed count from all 141 * mirrors */ 142 count = dreq->mirrors[0].count; 143 144 for (i = 1; i < dreq->mirror_count; i++) 145 count = min(count, dreq->mirrors[i].count); 146 147 dreq->count = count; 148 } 149 150 /* 151 * nfs_direct_select_verf - select the right verifier 152 * @dreq - direct request possibly spanning multiple servers 153 * @ds_clp - nfs_client of data server or NULL if MDS / non-pnfs 154 * @commit_idx - commit bucket index for the DS 155 * 156 * returns the correct verifier to use given the role of the server 157 */ 158 static struct nfs_writeverf * 159 nfs_direct_select_verf(struct nfs_direct_req *dreq, 160 struct nfs_client *ds_clp, 161 int commit_idx) 162 { 163 struct nfs_writeverf *verfp = &dreq->verf; 164 165 #ifdef CONFIG_NFS_V4_1 166 if (ds_clp) { 167 /* pNFS is in use, use the DS verf */ 168 if (commit_idx >= 0 && commit_idx < dreq->ds_cinfo.nbuckets) 169 verfp = &dreq->ds_cinfo.buckets[commit_idx].direct_verf; 170 else 171 WARN_ON_ONCE(1); 172 } 173 #endif 174 return verfp; 175 } 176 177 178 /* 179 * nfs_direct_set_hdr_verf - set the write/commit verifier 180 * @dreq - direct request possibly spanning multiple servers 181 * @hdr - pageio header to validate against previously seen verfs 182 * 183 * Set the server's (MDS or DS) "seen" verifier 184 */ 185 static void nfs_direct_set_hdr_verf(struct nfs_direct_req *dreq, 186 struct nfs_pgio_header *hdr) 187 { 188 struct nfs_writeverf *verfp; 189 190 verfp = nfs_direct_select_verf(dreq, hdr->ds_clp, hdr->ds_commit_idx); 191 WARN_ON_ONCE(verfp->committed >= 0); 192 memcpy(verfp, &hdr->verf, sizeof(struct nfs_writeverf)); 193 WARN_ON_ONCE(verfp->committed < 0); 194 } 195 196 /* 197 * nfs_direct_cmp_hdr_verf - compare verifier for pgio header 198 * @dreq - direct request possibly spanning multiple servers 199 * @hdr - pageio header to validate against previously seen verf 200 * 201 * set the server's "seen" verf if not initialized. 202 * returns result of comparison between @hdr->verf and the "seen" 203 * verf of the server used by @hdr (DS or MDS) 204 */ 205 static int nfs_direct_set_or_cmp_hdr_verf(struct nfs_direct_req *dreq, 206 struct nfs_pgio_header *hdr) 207 { 208 struct nfs_writeverf *verfp; 209 210 verfp = nfs_direct_select_verf(dreq, hdr->ds_clp, hdr->ds_commit_idx); 211 if (verfp->committed < 0) { 212 nfs_direct_set_hdr_verf(dreq, hdr); 213 return 0; 214 } 215 return memcmp(verfp, &hdr->verf, sizeof(struct nfs_writeverf)); 216 } 217 218 /* 219 * nfs_direct_cmp_commit_data_verf - compare verifier for commit data 220 * @dreq - direct request possibly spanning multiple servers 221 * @data - commit data to validate against previously seen verf 222 * 223 * returns result of comparison between @data->verf and the verf of 224 * the server used by @data (DS or MDS) 225 */ 226 static int nfs_direct_cmp_commit_data_verf(struct nfs_direct_req *dreq, 227 struct nfs_commit_data *data) 228 { 229 struct nfs_writeverf *verfp; 230 231 verfp = nfs_direct_select_verf(dreq, data->ds_clp, 232 data->ds_commit_index); 233 234 /* verifier not set so always fail */ 235 if (verfp->committed < 0) 236 return 1; 237 238 return memcmp(verfp, &data->verf, sizeof(struct nfs_writeverf)); 239 } 240 241 /** 242 * nfs_direct_IO - NFS address space operation for direct I/O 243 * @iocb: target I/O control block 244 * @iov: array of vectors that define I/O buffer 245 * @pos: offset in file to begin the operation 246 * @nr_segs: size of iovec array 247 * 248 * The presence of this routine in the address space ops vector means 249 * the NFS client supports direct I/O. However, for most direct IO, we 250 * shunt off direct read and write requests before the VFS gets them, 251 * so this method is only ever called for swap. 252 */ 253 ssize_t nfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t pos) 254 { 255 struct inode *inode = iocb->ki_filp->f_mapping->host; 256 257 /* we only support swap file calling nfs_direct_IO */ 258 if (!IS_SWAPFILE(inode)) 259 return 0; 260 261 #ifndef CONFIG_NFS_SWAP 262 dprintk("NFS: nfs_direct_IO (%pD) off/no(%Ld/%lu) EINVAL\n", 263 iocb->ki_filp, (long long) pos, iter->nr_segs); 264 265 return -EINVAL; 266 #else 267 VM_BUG_ON(iov_iter_count(iter) != PAGE_SIZE); 268 269 if (iov_iter_rw(iter) == READ) 270 return nfs_file_direct_read(iocb, iter, pos); 271 return nfs_file_direct_write(iocb, iter); 272 #endif /* CONFIG_NFS_SWAP */ 273 } 274 275 static void nfs_direct_release_pages(struct page **pages, unsigned int npages) 276 { 277 unsigned int i; 278 for (i = 0; i < npages; i++) 279 page_cache_release(pages[i]); 280 } 281 282 void nfs_init_cinfo_from_dreq(struct nfs_commit_info *cinfo, 283 struct nfs_direct_req *dreq) 284 { 285 cinfo->lock = &dreq->inode->i_lock; 286 cinfo->mds = &dreq->mds_cinfo; 287 cinfo->ds = &dreq->ds_cinfo; 288 cinfo->dreq = dreq; 289 cinfo->completion_ops = &nfs_direct_commit_completion_ops; 290 } 291 292 static inline void nfs_direct_setup_mirroring(struct nfs_direct_req *dreq, 293 struct nfs_pageio_descriptor *pgio, 294 struct nfs_page *req) 295 { 296 int mirror_count = 1; 297 298 if (pgio->pg_ops->pg_get_mirror_count) 299 mirror_count = pgio->pg_ops->pg_get_mirror_count(pgio, req); 300 301 dreq->mirror_count = mirror_count; 302 } 303 304 static inline struct nfs_direct_req *nfs_direct_req_alloc(void) 305 { 306 struct nfs_direct_req *dreq; 307 308 dreq = kmem_cache_zalloc(nfs_direct_cachep, GFP_KERNEL); 309 if (!dreq) 310 return NULL; 311 312 kref_init(&dreq->kref); 313 kref_get(&dreq->kref); 314 init_completion(&dreq->completion); 315 INIT_LIST_HEAD(&dreq->mds_cinfo.list); 316 dreq->verf.committed = NFS_INVALID_STABLE_HOW; /* not set yet */ 317 INIT_WORK(&dreq->work, nfs_direct_write_schedule_work); 318 dreq->mirror_count = 1; 319 spin_lock_init(&dreq->lock); 320 321 return dreq; 322 } 323 324 static void nfs_direct_req_free(struct kref *kref) 325 { 326 struct nfs_direct_req *dreq = container_of(kref, struct nfs_direct_req, kref); 327 328 nfs_free_pnfs_ds_cinfo(&dreq->ds_cinfo); 329 if (dreq->l_ctx != NULL) 330 nfs_put_lock_context(dreq->l_ctx); 331 if (dreq->ctx != NULL) 332 put_nfs_open_context(dreq->ctx); 333 kmem_cache_free(nfs_direct_cachep, dreq); 334 } 335 336 static void nfs_direct_req_release(struct nfs_direct_req *dreq) 337 { 338 kref_put(&dreq->kref, nfs_direct_req_free); 339 } 340 341 ssize_t nfs_dreq_bytes_left(struct nfs_direct_req *dreq) 342 { 343 return dreq->bytes_left; 344 } 345 EXPORT_SYMBOL_GPL(nfs_dreq_bytes_left); 346 347 /* 348 * Collects and returns the final error value/byte-count. 349 */ 350 static ssize_t nfs_direct_wait(struct nfs_direct_req *dreq) 351 { 352 ssize_t result = -EIOCBQUEUED; 353 354 /* Async requests don't wait here */ 355 if (dreq->iocb) 356 goto out; 357 358 result = wait_for_completion_killable(&dreq->completion); 359 360 if (!result) 361 result = dreq->error; 362 if (!result) 363 result = dreq->count; 364 365 out: 366 return (ssize_t) result; 367 } 368 369 /* 370 * Synchronous I/O uses a stack-allocated iocb. Thus we can't trust 371 * the iocb is still valid here if this is a synchronous request. 372 */ 373 static void nfs_direct_complete(struct nfs_direct_req *dreq, bool write) 374 { 375 struct inode *inode = dreq->inode; 376 377 if (dreq->iocb && write) { 378 loff_t pos = dreq->iocb->ki_pos + dreq->count; 379 380 spin_lock(&inode->i_lock); 381 if (i_size_read(inode) < pos) 382 i_size_write(inode, pos); 383 spin_unlock(&inode->i_lock); 384 } 385 386 if (write) 387 nfs_zap_mapping(inode, inode->i_mapping); 388 389 inode_dio_done(inode); 390 391 if (dreq->iocb) { 392 long res = (long) dreq->error; 393 if (!res) 394 res = (long) dreq->count; 395 dreq->iocb->ki_complete(dreq->iocb, res, 0); 396 } 397 398 complete_all(&dreq->completion); 399 400 nfs_direct_req_release(dreq); 401 } 402 403 static void nfs_direct_readpage_release(struct nfs_page *req) 404 { 405 dprintk("NFS: direct read done (%s/%llu %d@%lld)\n", 406 req->wb_context->dentry->d_inode->i_sb->s_id, 407 (unsigned long long)NFS_FILEID(req->wb_context->dentry->d_inode), 408 req->wb_bytes, 409 (long long)req_offset(req)); 410 nfs_release_request(req); 411 } 412 413 static void nfs_direct_read_completion(struct nfs_pgio_header *hdr) 414 { 415 unsigned long bytes = 0; 416 struct nfs_direct_req *dreq = hdr->dreq; 417 418 if (test_bit(NFS_IOHDR_REDO, &hdr->flags)) 419 goto out_put; 420 421 spin_lock(&dreq->lock); 422 if (test_bit(NFS_IOHDR_ERROR, &hdr->flags) && (hdr->good_bytes == 0)) 423 dreq->error = hdr->error; 424 else 425 nfs_direct_good_bytes(dreq, hdr); 426 427 spin_unlock(&dreq->lock); 428 429 while (!list_empty(&hdr->pages)) { 430 struct nfs_page *req = nfs_list_entry(hdr->pages.next); 431 struct page *page = req->wb_page; 432 433 if (!PageCompound(page) && bytes < hdr->good_bytes) 434 set_page_dirty(page); 435 bytes += req->wb_bytes; 436 nfs_list_remove_request(req); 437 nfs_direct_readpage_release(req); 438 } 439 out_put: 440 if (put_dreq(dreq)) 441 nfs_direct_complete(dreq, false); 442 hdr->release(hdr); 443 } 444 445 static void nfs_read_sync_pgio_error(struct list_head *head) 446 { 447 struct nfs_page *req; 448 449 while (!list_empty(head)) { 450 req = nfs_list_entry(head->next); 451 nfs_list_remove_request(req); 452 nfs_release_request(req); 453 } 454 } 455 456 static void nfs_direct_pgio_init(struct nfs_pgio_header *hdr) 457 { 458 get_dreq(hdr->dreq); 459 } 460 461 static const struct nfs_pgio_completion_ops nfs_direct_read_completion_ops = { 462 .error_cleanup = nfs_read_sync_pgio_error, 463 .init_hdr = nfs_direct_pgio_init, 464 .completion = nfs_direct_read_completion, 465 }; 466 467 /* 468 * For each rsize'd chunk of the user's buffer, dispatch an NFS READ 469 * operation. If nfs_readdata_alloc() or get_user_pages() fails, 470 * bail and stop sending more reads. Read length accounting is 471 * handled automatically by nfs_direct_read_result(). Otherwise, if 472 * no requests have been sent, just return an error. 473 */ 474 475 static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq, 476 struct iov_iter *iter, 477 loff_t pos) 478 { 479 struct nfs_pageio_descriptor desc; 480 struct inode *inode = dreq->inode; 481 ssize_t result = -EINVAL; 482 size_t requested_bytes = 0; 483 size_t rsize = max_t(size_t, NFS_SERVER(inode)->rsize, PAGE_SIZE); 484 485 nfs_pageio_init_read(&desc, dreq->inode, false, 486 &nfs_direct_read_completion_ops); 487 get_dreq(dreq); 488 desc.pg_dreq = dreq; 489 atomic_inc(&inode->i_dio_count); 490 491 while (iov_iter_count(iter)) { 492 struct page **pagevec; 493 size_t bytes; 494 size_t pgbase; 495 unsigned npages, i; 496 497 result = iov_iter_get_pages_alloc(iter, &pagevec, 498 rsize, &pgbase); 499 if (result < 0) 500 break; 501 502 bytes = result; 503 iov_iter_advance(iter, bytes); 504 npages = (result + pgbase + PAGE_SIZE - 1) / PAGE_SIZE; 505 for (i = 0; i < npages; i++) { 506 struct nfs_page *req; 507 unsigned int req_len = min_t(size_t, bytes, PAGE_SIZE - pgbase); 508 /* XXX do we need to do the eof zeroing found in async_filler? */ 509 req = nfs_create_request(dreq->ctx, pagevec[i], NULL, 510 pgbase, req_len); 511 if (IS_ERR(req)) { 512 result = PTR_ERR(req); 513 break; 514 } 515 req->wb_index = pos >> PAGE_SHIFT; 516 req->wb_offset = pos & ~PAGE_MASK; 517 if (!nfs_pageio_add_request(&desc, req)) { 518 result = desc.pg_error; 519 nfs_release_request(req); 520 break; 521 } 522 pgbase = 0; 523 bytes -= req_len; 524 requested_bytes += req_len; 525 pos += req_len; 526 dreq->bytes_left -= req_len; 527 } 528 nfs_direct_release_pages(pagevec, npages); 529 kvfree(pagevec); 530 if (result < 0) 531 break; 532 } 533 534 nfs_pageio_complete(&desc); 535 536 /* 537 * If no bytes were started, return the error, and let the 538 * generic layer handle the completion. 539 */ 540 if (requested_bytes == 0) { 541 inode_dio_done(inode); 542 nfs_direct_req_release(dreq); 543 return result < 0 ? result : -EIO; 544 } 545 546 if (put_dreq(dreq)) 547 nfs_direct_complete(dreq, false); 548 return 0; 549 } 550 551 /** 552 * nfs_file_direct_read - file direct read operation for NFS files 553 * @iocb: target I/O control block 554 * @iter: vector of user buffers into which to read data 555 * @pos: byte offset in file where reading starts 556 * 557 * We use this function for direct reads instead of calling 558 * generic_file_aio_read() in order to avoid gfar's check to see if 559 * the request starts before the end of the file. For that check 560 * to work, we must generate a GETATTR before each direct read, and 561 * even then there is a window between the GETATTR and the subsequent 562 * READ where the file size could change. Our preference is simply 563 * to do all reads the application wants, and the server will take 564 * care of managing the end of file boundary. 565 * 566 * This function also eliminates unnecessarily updating the file's 567 * atime locally, as the NFS server sets the file's atime, and this 568 * client must read the updated atime from the server back into its 569 * cache. 570 */ 571 ssize_t nfs_file_direct_read(struct kiocb *iocb, struct iov_iter *iter, 572 loff_t pos) 573 { 574 struct file *file = iocb->ki_filp; 575 struct address_space *mapping = file->f_mapping; 576 struct inode *inode = mapping->host; 577 struct nfs_direct_req *dreq; 578 struct nfs_lock_context *l_ctx; 579 ssize_t result = -EINVAL; 580 size_t count = iov_iter_count(iter); 581 nfs_add_stats(mapping->host, NFSIOS_DIRECTREADBYTES, count); 582 583 dfprintk(FILE, "NFS: direct read(%pD2, %zd@%Ld)\n", 584 file, count, (long long) pos); 585 586 result = 0; 587 if (!count) 588 goto out; 589 590 mutex_lock(&inode->i_mutex); 591 result = nfs_sync_mapping(mapping); 592 if (result) 593 goto out_unlock; 594 595 task_io_account_read(count); 596 597 result = -ENOMEM; 598 dreq = nfs_direct_req_alloc(); 599 if (dreq == NULL) 600 goto out_unlock; 601 602 dreq->inode = inode; 603 dreq->bytes_left = count; 604 dreq->io_start = pos; 605 dreq->ctx = get_nfs_open_context(nfs_file_open_context(iocb->ki_filp)); 606 l_ctx = nfs_get_lock_context(dreq->ctx); 607 if (IS_ERR(l_ctx)) { 608 result = PTR_ERR(l_ctx); 609 goto out_release; 610 } 611 dreq->l_ctx = l_ctx; 612 if (!is_sync_kiocb(iocb)) 613 dreq->iocb = iocb; 614 615 NFS_I(inode)->read_io += count; 616 result = nfs_direct_read_schedule_iovec(dreq, iter, pos); 617 618 mutex_unlock(&inode->i_mutex); 619 620 if (!result) { 621 result = nfs_direct_wait(dreq); 622 if (result > 0) 623 iocb->ki_pos = pos + result; 624 } 625 626 nfs_direct_req_release(dreq); 627 return result; 628 629 out_release: 630 nfs_direct_req_release(dreq); 631 out_unlock: 632 mutex_unlock(&inode->i_mutex); 633 out: 634 return result; 635 } 636 637 static void 638 nfs_direct_write_scan_commit_list(struct inode *inode, 639 struct list_head *list, 640 struct nfs_commit_info *cinfo) 641 { 642 spin_lock(cinfo->lock); 643 #ifdef CONFIG_NFS_V4_1 644 if (cinfo->ds != NULL && cinfo->ds->nwritten != 0) 645 NFS_SERVER(inode)->pnfs_curr_ld->recover_commit_reqs(list, cinfo); 646 #endif 647 nfs_scan_commit_list(&cinfo->mds->list, list, cinfo, 0); 648 spin_unlock(cinfo->lock); 649 } 650 651 static void nfs_direct_write_reschedule(struct nfs_direct_req *dreq) 652 { 653 struct nfs_pageio_descriptor desc; 654 struct nfs_page *req, *tmp; 655 LIST_HEAD(reqs); 656 struct nfs_commit_info cinfo; 657 LIST_HEAD(failed); 658 int i; 659 660 nfs_init_cinfo_from_dreq(&cinfo, dreq); 661 nfs_direct_write_scan_commit_list(dreq->inode, &reqs, &cinfo); 662 663 dreq->count = 0; 664 for (i = 0; i < dreq->mirror_count; i++) 665 dreq->mirrors[i].count = 0; 666 get_dreq(dreq); 667 668 nfs_pageio_init_write(&desc, dreq->inode, FLUSH_STABLE, false, 669 &nfs_direct_write_completion_ops); 670 desc.pg_dreq = dreq; 671 672 req = nfs_list_entry(reqs.next); 673 nfs_direct_setup_mirroring(dreq, &desc, req); 674 675 list_for_each_entry_safe(req, tmp, &reqs, wb_list) { 676 if (!nfs_pageio_add_request(&desc, req)) { 677 nfs_list_remove_request(req); 678 nfs_list_add_request(req, &failed); 679 spin_lock(cinfo.lock); 680 dreq->flags = 0; 681 dreq->error = -EIO; 682 spin_unlock(cinfo.lock); 683 } 684 nfs_release_request(req); 685 } 686 nfs_pageio_complete(&desc); 687 688 while (!list_empty(&failed)) { 689 req = nfs_list_entry(failed.next); 690 nfs_list_remove_request(req); 691 nfs_unlock_and_release_request(req); 692 } 693 694 if (put_dreq(dreq)) 695 nfs_direct_write_complete(dreq, dreq->inode); 696 } 697 698 static void nfs_direct_commit_complete(struct nfs_commit_data *data) 699 { 700 struct nfs_direct_req *dreq = data->dreq; 701 struct nfs_commit_info cinfo; 702 struct nfs_page *req; 703 int status = data->task.tk_status; 704 705 nfs_init_cinfo_from_dreq(&cinfo, dreq); 706 if (status < 0) { 707 dprintk("NFS: %5u commit failed with error %d.\n", 708 data->task.tk_pid, status); 709 dreq->flags = NFS_ODIRECT_RESCHED_WRITES; 710 } else if (nfs_direct_cmp_commit_data_verf(dreq, data)) { 711 dprintk("NFS: %5u commit verify failed\n", data->task.tk_pid); 712 dreq->flags = NFS_ODIRECT_RESCHED_WRITES; 713 } 714 715 dprintk("NFS: %5u commit returned %d\n", data->task.tk_pid, status); 716 while (!list_empty(&data->pages)) { 717 req = nfs_list_entry(data->pages.next); 718 nfs_list_remove_request(req); 719 if (dreq->flags == NFS_ODIRECT_RESCHED_WRITES) { 720 /* Note the rewrite will go through mds */ 721 nfs_mark_request_commit(req, NULL, &cinfo, 0); 722 } else 723 nfs_release_request(req); 724 nfs_unlock_and_release_request(req); 725 } 726 727 if (atomic_dec_and_test(&cinfo.mds->rpcs_out)) 728 nfs_direct_write_complete(dreq, data->inode); 729 } 730 731 static void nfs_direct_error_cleanup(struct nfs_inode *nfsi) 732 { 733 /* There is no lock to clear */ 734 } 735 736 static const struct nfs_commit_completion_ops nfs_direct_commit_completion_ops = { 737 .completion = nfs_direct_commit_complete, 738 .error_cleanup = nfs_direct_error_cleanup, 739 }; 740 741 static void nfs_direct_commit_schedule(struct nfs_direct_req *dreq) 742 { 743 int res; 744 struct nfs_commit_info cinfo; 745 LIST_HEAD(mds_list); 746 747 nfs_init_cinfo_from_dreq(&cinfo, dreq); 748 nfs_scan_commit(dreq->inode, &mds_list, &cinfo); 749 res = nfs_generic_commit_list(dreq->inode, &mds_list, 0, &cinfo); 750 if (res < 0) /* res == -ENOMEM */ 751 nfs_direct_write_reschedule(dreq); 752 } 753 754 static void nfs_direct_write_schedule_work(struct work_struct *work) 755 { 756 struct nfs_direct_req *dreq = container_of(work, struct nfs_direct_req, work); 757 int flags = dreq->flags; 758 759 dreq->flags = 0; 760 switch (flags) { 761 case NFS_ODIRECT_DO_COMMIT: 762 nfs_direct_commit_schedule(dreq); 763 break; 764 case NFS_ODIRECT_RESCHED_WRITES: 765 nfs_direct_write_reschedule(dreq); 766 break; 767 default: 768 nfs_direct_complete(dreq, true); 769 } 770 } 771 772 static void nfs_direct_write_complete(struct nfs_direct_req *dreq, struct inode *inode) 773 { 774 schedule_work(&dreq->work); /* Calls nfs_direct_write_schedule_work */ 775 } 776 777 static void nfs_direct_write_completion(struct nfs_pgio_header *hdr) 778 { 779 struct nfs_direct_req *dreq = hdr->dreq; 780 struct nfs_commit_info cinfo; 781 bool request_commit = false; 782 struct nfs_page *req = nfs_list_entry(hdr->pages.next); 783 784 if (test_bit(NFS_IOHDR_REDO, &hdr->flags)) 785 goto out_put; 786 787 nfs_init_cinfo_from_dreq(&cinfo, dreq); 788 789 spin_lock(&dreq->lock); 790 791 if (test_bit(NFS_IOHDR_ERROR, &hdr->flags)) { 792 dreq->flags = 0; 793 dreq->error = hdr->error; 794 } 795 if (dreq->error == 0) { 796 nfs_direct_good_bytes(dreq, hdr); 797 if (nfs_write_need_commit(hdr)) { 798 if (dreq->flags == NFS_ODIRECT_RESCHED_WRITES) 799 request_commit = true; 800 else if (dreq->flags == 0) { 801 nfs_direct_set_hdr_verf(dreq, hdr); 802 request_commit = true; 803 dreq->flags = NFS_ODIRECT_DO_COMMIT; 804 } else if (dreq->flags == NFS_ODIRECT_DO_COMMIT) { 805 request_commit = true; 806 if (nfs_direct_set_or_cmp_hdr_verf(dreq, hdr)) 807 dreq->flags = 808 NFS_ODIRECT_RESCHED_WRITES; 809 } 810 } 811 } 812 spin_unlock(&dreq->lock); 813 814 while (!list_empty(&hdr->pages)) { 815 816 req = nfs_list_entry(hdr->pages.next); 817 nfs_list_remove_request(req); 818 if (request_commit) { 819 kref_get(&req->wb_kref); 820 nfs_mark_request_commit(req, hdr->lseg, &cinfo, 821 hdr->ds_commit_idx); 822 } 823 nfs_unlock_and_release_request(req); 824 } 825 826 out_put: 827 if (put_dreq(dreq)) 828 nfs_direct_write_complete(dreq, hdr->inode); 829 hdr->release(hdr); 830 } 831 832 static void nfs_write_sync_pgio_error(struct list_head *head) 833 { 834 struct nfs_page *req; 835 836 while (!list_empty(head)) { 837 req = nfs_list_entry(head->next); 838 nfs_list_remove_request(req); 839 nfs_unlock_and_release_request(req); 840 } 841 } 842 843 static const struct nfs_pgio_completion_ops nfs_direct_write_completion_ops = { 844 .error_cleanup = nfs_write_sync_pgio_error, 845 .init_hdr = nfs_direct_pgio_init, 846 .completion = nfs_direct_write_completion, 847 }; 848 849 850 /* 851 * NB: Return the value of the first error return code. Subsequent 852 * errors after the first one are ignored. 853 */ 854 /* 855 * For each wsize'd chunk of the user's buffer, dispatch an NFS WRITE 856 * operation. If nfs_writedata_alloc() or get_user_pages() fails, 857 * bail and stop sending more writes. Write length accounting is 858 * handled automatically by nfs_direct_write_result(). Otherwise, if 859 * no requests have been sent, just return an error. 860 */ 861 static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq, 862 struct iov_iter *iter, 863 loff_t pos) 864 { 865 struct nfs_pageio_descriptor desc; 866 struct inode *inode = dreq->inode; 867 ssize_t result = 0; 868 size_t requested_bytes = 0; 869 size_t wsize = max_t(size_t, NFS_SERVER(inode)->wsize, PAGE_SIZE); 870 871 nfs_pageio_init_write(&desc, inode, FLUSH_COND_STABLE, false, 872 &nfs_direct_write_completion_ops); 873 desc.pg_dreq = dreq; 874 get_dreq(dreq); 875 atomic_inc(&inode->i_dio_count); 876 877 NFS_I(inode)->write_io += iov_iter_count(iter); 878 while (iov_iter_count(iter)) { 879 struct page **pagevec; 880 size_t bytes; 881 size_t pgbase; 882 unsigned npages, i; 883 884 result = iov_iter_get_pages_alloc(iter, &pagevec, 885 wsize, &pgbase); 886 if (result < 0) 887 break; 888 889 bytes = result; 890 iov_iter_advance(iter, bytes); 891 npages = (result + pgbase + PAGE_SIZE - 1) / PAGE_SIZE; 892 for (i = 0; i < npages; i++) { 893 struct nfs_page *req; 894 unsigned int req_len = min_t(size_t, bytes, PAGE_SIZE - pgbase); 895 896 req = nfs_create_request(dreq->ctx, pagevec[i], NULL, 897 pgbase, req_len); 898 if (IS_ERR(req)) { 899 result = PTR_ERR(req); 900 break; 901 } 902 903 nfs_direct_setup_mirroring(dreq, &desc, req); 904 905 nfs_lock_request(req); 906 req->wb_index = pos >> PAGE_SHIFT; 907 req->wb_offset = pos & ~PAGE_MASK; 908 if (!nfs_pageio_add_request(&desc, req)) { 909 result = desc.pg_error; 910 nfs_unlock_and_release_request(req); 911 break; 912 } 913 pgbase = 0; 914 bytes -= req_len; 915 requested_bytes += req_len; 916 pos += req_len; 917 dreq->bytes_left -= req_len; 918 } 919 nfs_direct_release_pages(pagevec, npages); 920 kvfree(pagevec); 921 if (result < 0) 922 break; 923 } 924 nfs_pageio_complete(&desc); 925 926 /* 927 * If no bytes were started, return the error, and let the 928 * generic layer handle the completion. 929 */ 930 if (requested_bytes == 0) { 931 inode_dio_done(inode); 932 nfs_direct_req_release(dreq); 933 return result < 0 ? result : -EIO; 934 } 935 936 if (put_dreq(dreq)) 937 nfs_direct_write_complete(dreq, dreq->inode); 938 return 0; 939 } 940 941 /** 942 * nfs_file_direct_write - file direct write operation for NFS files 943 * @iocb: target I/O control block 944 * @iter: vector of user buffers from which to write data 945 * @pos: byte offset in file where writing starts 946 * 947 * We use this function for direct writes instead of calling 948 * generic_file_aio_write() in order to avoid taking the inode 949 * semaphore and updating the i_size. The NFS server will set 950 * the new i_size and this client must read the updated size 951 * back into its cache. We let the server do generic write 952 * parameter checking and report problems. 953 * 954 * We eliminate local atime updates, see direct read above. 955 * 956 * We avoid unnecessary page cache invalidations for normal cached 957 * readers of this file. 958 * 959 * Note that O_APPEND is not supported for NFS direct writes, as there 960 * is no atomic O_APPEND write facility in the NFS protocol. 961 */ 962 ssize_t nfs_file_direct_write(struct kiocb *iocb, struct iov_iter *iter) 963 { 964 ssize_t result = -EINVAL; 965 struct file *file = iocb->ki_filp; 966 struct address_space *mapping = file->f_mapping; 967 struct inode *inode = mapping->host; 968 struct nfs_direct_req *dreq; 969 struct nfs_lock_context *l_ctx; 970 loff_t pos, end; 971 972 dfprintk(FILE, "NFS: direct write(%pD2, %zd@%Ld)\n", 973 file, iov_iter_count(iter), (long long) iocb->ki_pos); 974 975 nfs_add_stats(mapping->host, NFSIOS_DIRECTWRITTENBYTES, 976 iov_iter_count(iter)); 977 978 pos = iocb->ki_pos; 979 end = (pos + iov_iter_count(iter) - 1) >> PAGE_CACHE_SHIFT; 980 981 mutex_lock(&inode->i_mutex); 982 983 result = nfs_sync_mapping(mapping); 984 if (result) 985 goto out_unlock; 986 987 if (mapping->nrpages) { 988 result = invalidate_inode_pages2_range(mapping, 989 pos >> PAGE_CACHE_SHIFT, end); 990 if (result) 991 goto out_unlock; 992 } 993 994 task_io_account_write(iov_iter_count(iter)); 995 996 result = -ENOMEM; 997 dreq = nfs_direct_req_alloc(); 998 if (!dreq) 999 goto out_unlock; 1000 1001 dreq->inode = inode; 1002 dreq->bytes_left = iov_iter_count(iter); 1003 dreq->io_start = pos; 1004 dreq->ctx = get_nfs_open_context(nfs_file_open_context(iocb->ki_filp)); 1005 l_ctx = nfs_get_lock_context(dreq->ctx); 1006 if (IS_ERR(l_ctx)) { 1007 result = PTR_ERR(l_ctx); 1008 goto out_release; 1009 } 1010 dreq->l_ctx = l_ctx; 1011 if (!is_sync_kiocb(iocb)) 1012 dreq->iocb = iocb; 1013 1014 result = nfs_direct_write_schedule_iovec(dreq, iter, pos); 1015 1016 if (mapping->nrpages) { 1017 invalidate_inode_pages2_range(mapping, 1018 pos >> PAGE_CACHE_SHIFT, end); 1019 } 1020 1021 mutex_unlock(&inode->i_mutex); 1022 1023 if (!result) { 1024 result = nfs_direct_wait(dreq); 1025 if (result > 0) { 1026 struct inode *inode = mapping->host; 1027 1028 iocb->ki_pos = pos + result; 1029 spin_lock(&inode->i_lock); 1030 if (i_size_read(inode) < iocb->ki_pos) 1031 i_size_write(inode, iocb->ki_pos); 1032 spin_unlock(&inode->i_lock); 1033 } 1034 } 1035 nfs_direct_req_release(dreq); 1036 return result; 1037 1038 out_release: 1039 nfs_direct_req_release(dreq); 1040 out_unlock: 1041 mutex_unlock(&inode->i_mutex); 1042 return result; 1043 } 1044 1045 /** 1046 * nfs_init_directcache - create a slab cache for nfs_direct_req structures 1047 * 1048 */ 1049 int __init nfs_init_directcache(void) 1050 { 1051 nfs_direct_cachep = kmem_cache_create("nfs_direct_cache", 1052 sizeof(struct nfs_direct_req), 1053 0, (SLAB_RECLAIM_ACCOUNT| 1054 SLAB_MEM_SPREAD), 1055 NULL); 1056 if (nfs_direct_cachep == NULL) 1057 return -ENOMEM; 1058 1059 return 0; 1060 } 1061 1062 /** 1063 * nfs_destroy_directcache - destroy the slab cache for nfs_direct_req structures 1064 * 1065 */ 1066 void nfs_destroy_directcache(void) 1067 { 1068 kmem_cache_destroy(nfs_direct_cachep); 1069 } 1070