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