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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 | ||
49 | #include <linux/nfs_fs.h> | |
50 | #include <linux/nfs_page.h> | |
51 | #include <linux/sunrpc/clnt.h> | |
52 | ||
53 | #include <asm/system.h> | |
54 | #include <asm/uaccess.h> | |
55 | #include <asm/atomic.h> | |
56 | ||
57 | #include "internal.h" | |
58 | #include "iostat.h" | |
59 | ||
60 | #define NFSDBG_FACILITY NFSDBG_VFS | |
61 | ||
62 | static struct kmem_cache *nfs_direct_cachep; | |
63 | ||
64 | /* | |
65 | * This represents a set of asynchronous requests that we're waiting on | |
66 | */ | |
67 | struct nfs_direct_req { | |
68 | struct kref kref; /* release manager */ | |
69 | ||
70 | /* I/O parameters */ | |
71 | struct nfs_open_context *ctx; /* file open context info */ | |
72 | struct kiocb * iocb; /* controlling i/o request */ | |
73 | struct inode * inode; /* target file of i/o */ | |
74 | ||
75 | /* completion state */ | |
76 | atomic_t io_count; /* i/os we're waiting for */ | |
77 | spinlock_t lock; /* protect completion state */ | |
78 | ssize_t count, /* bytes actually processed */ | |
79 | error; /* any reported error */ | |
80 | struct completion completion; /* wait for i/o completion */ | |
81 | ||
82 | /* commit state */ | |
83 | struct list_head rewrite_list; /* saved nfs_write_data structs */ | |
84 | struct nfs_write_data * commit_data; /* special write_data for commits */ | |
85 | int flags; | |
86 | #define NFS_ODIRECT_DO_COMMIT (1) /* an unstable reply was received */ | |
87 | #define NFS_ODIRECT_RESCHED_WRITES (2) /* write verification failed */ | |
88 | struct nfs_writeverf verf; /* unstable write verifier */ | |
89 | }; | |
90 | ||
91 | static void nfs_direct_write_complete(struct nfs_direct_req *dreq, struct inode *inode); | |
92 | static const struct rpc_call_ops nfs_write_direct_ops; | |
93 | ||
94 | static inline void get_dreq(struct nfs_direct_req *dreq) | |
95 | { | |
96 | atomic_inc(&dreq->io_count); | |
97 | } | |
98 | ||
99 | static inline int put_dreq(struct nfs_direct_req *dreq) | |
100 | { | |
101 | return atomic_dec_and_test(&dreq->io_count); | |
102 | } | |
103 | ||
104 | /** | |
105 | * nfs_direct_IO - NFS address space operation for direct I/O | |
106 | * @rw: direction (read or write) | |
107 | * @iocb: target I/O control block | |
108 | * @iov: array of vectors that define I/O buffer | |
109 | * @pos: offset in file to begin the operation | |
110 | * @nr_segs: size of iovec array | |
111 | * | |
112 | * The presence of this routine in the address space ops vector means | |
113 | * the NFS client supports direct I/O. However, we shunt off direct | |
114 | * read and write requests before the VFS gets them, so this method | |
115 | * should never be called. | |
116 | */ | |
117 | ssize_t nfs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, loff_t pos, unsigned long nr_segs) | |
118 | { | |
119 | dprintk("NFS: nfs_direct_IO (%s) off/no(%Ld/%lu) EINVAL\n", | |
120 | iocb->ki_filp->f_path.dentry->d_name.name, | |
121 | (long long) pos, nr_segs); | |
122 | ||
123 | return -EINVAL; | |
124 | } | |
125 | ||
126 | static void nfs_direct_dirty_pages(struct page **pages, unsigned int pgbase, size_t count) | |
127 | { | |
128 | unsigned int npages; | |
129 | unsigned int i; | |
130 | ||
131 | if (count == 0) | |
132 | return; | |
133 | pages += (pgbase >> PAGE_SHIFT); | |
134 | npages = (count + (pgbase & ~PAGE_MASK) + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
135 | for (i = 0; i < npages; i++) { | |
136 | struct page *page = pages[i]; | |
137 | if (!PageCompound(page)) | |
138 | set_page_dirty(page); | |
139 | } | |
140 | } | |
141 | ||
142 | static void nfs_direct_release_pages(struct page **pages, unsigned int npages) | |
143 | { | |
144 | unsigned int i; | |
145 | for (i = 0; i < npages; i++) | |
146 | page_cache_release(pages[i]); | |
147 | } | |
148 | ||
149 | static inline struct nfs_direct_req *nfs_direct_req_alloc(void) | |
150 | { | |
151 | struct nfs_direct_req *dreq; | |
152 | ||
153 | dreq = kmem_cache_alloc(nfs_direct_cachep, GFP_KERNEL); | |
154 | if (!dreq) | |
155 | return NULL; | |
156 | ||
157 | kref_init(&dreq->kref); | |
158 | kref_get(&dreq->kref); | |
159 | init_completion(&dreq->completion); | |
160 | INIT_LIST_HEAD(&dreq->rewrite_list); | |
161 | dreq->iocb = NULL; | |
162 | dreq->ctx = NULL; | |
163 | spin_lock_init(&dreq->lock); | |
164 | atomic_set(&dreq->io_count, 0); | |
165 | dreq->count = 0; | |
166 | dreq->error = 0; | |
167 | dreq->flags = 0; | |
168 | ||
169 | return dreq; | |
170 | } | |
171 | ||
172 | static void nfs_direct_req_free(struct kref *kref) | |
173 | { | |
174 | struct nfs_direct_req *dreq = container_of(kref, struct nfs_direct_req, kref); | |
175 | ||
176 | if (dreq->ctx != NULL) | |
177 | put_nfs_open_context(dreq->ctx); | |
178 | kmem_cache_free(nfs_direct_cachep, dreq); | |
179 | } | |
180 | ||
181 | static void nfs_direct_req_release(struct nfs_direct_req *dreq) | |
182 | { | |
183 | kref_put(&dreq->kref, nfs_direct_req_free); | |
184 | } | |
185 | ||
186 | /* | |
187 | * Collects and returns the final error value/byte-count. | |
188 | */ | |
189 | static ssize_t nfs_direct_wait(struct nfs_direct_req *dreq) | |
190 | { | |
191 | ssize_t result = -EIOCBQUEUED; | |
192 | ||
193 | /* Async requests don't wait here */ | |
194 | if (dreq->iocb) | |
195 | goto out; | |
196 | ||
197 | result = wait_for_completion_killable(&dreq->completion); | |
198 | ||
199 | if (!result) | |
200 | result = dreq->error; | |
201 | if (!result) | |
202 | result = dreq->count; | |
203 | ||
204 | out: | |
205 | return (ssize_t) result; | |
206 | } | |
207 | ||
208 | /* | |
209 | * Synchronous I/O uses a stack-allocated iocb. Thus we can't trust | |
210 | * the iocb is still valid here if this is a synchronous request. | |
211 | */ | |
212 | static void nfs_direct_complete(struct nfs_direct_req *dreq) | |
213 | { | |
214 | if (dreq->iocb) { | |
215 | long res = (long) dreq->error; | |
216 | if (!res) | |
217 | res = (long) dreq->count; | |
218 | aio_complete(dreq->iocb, res, 0); | |
219 | } | |
220 | complete_all(&dreq->completion); | |
221 | ||
222 | nfs_direct_req_release(dreq); | |
223 | } | |
224 | ||
225 | /* | |
226 | * We must hold a reference to all the pages in this direct read request | |
227 | * until the RPCs complete. This could be long *after* we are woken up in | |
228 | * nfs_direct_wait (for instance, if someone hits ^C on a slow server). | |
229 | */ | |
230 | static void nfs_direct_read_result(struct rpc_task *task, void *calldata) | |
231 | { | |
232 | struct nfs_read_data *data = calldata; | |
233 | ||
234 | nfs_readpage_result(task, data); | |
235 | } | |
236 | ||
237 | static void nfs_direct_read_release(void *calldata) | |
238 | { | |
239 | ||
240 | struct nfs_read_data *data = calldata; | |
241 | struct nfs_direct_req *dreq = (struct nfs_direct_req *) data->req; | |
242 | int status = data->task.tk_status; | |
243 | ||
244 | spin_lock(&dreq->lock); | |
245 | if (unlikely(status < 0)) { | |
246 | dreq->error = status; | |
247 | spin_unlock(&dreq->lock); | |
248 | } else { | |
249 | dreq->count += data->res.count; | |
250 | spin_unlock(&dreq->lock); | |
251 | nfs_direct_dirty_pages(data->pagevec, | |
252 | data->args.pgbase, | |
253 | data->res.count); | |
254 | } | |
255 | nfs_direct_release_pages(data->pagevec, data->npages); | |
256 | ||
257 | if (put_dreq(dreq)) | |
258 | nfs_direct_complete(dreq); | |
259 | nfs_readdata_free(data); | |
260 | } | |
261 | ||
262 | static const struct rpc_call_ops nfs_read_direct_ops = { | |
263 | #if defined(CONFIG_NFS_V4_1) | |
264 | .rpc_call_prepare = nfs_read_prepare, | |
265 | #endif /* CONFIG_NFS_V4_1 */ | |
266 | .rpc_call_done = nfs_direct_read_result, | |
267 | .rpc_release = nfs_direct_read_release, | |
268 | }; | |
269 | ||
270 | /* | |
271 | * For each rsize'd chunk of the user's buffer, dispatch an NFS READ | |
272 | * operation. If nfs_readdata_alloc() or get_user_pages() fails, | |
273 | * bail and stop sending more reads. Read length accounting is | |
274 | * handled automatically by nfs_direct_read_result(). Otherwise, if | |
275 | * no requests have been sent, just return an error. | |
276 | */ | |
277 | static ssize_t nfs_direct_read_schedule_segment(struct nfs_direct_req *dreq, | |
278 | const struct iovec *iov, | |
279 | loff_t pos) | |
280 | { | |
281 | struct nfs_open_context *ctx = dreq->ctx; | |
282 | struct inode *inode = ctx->path.dentry->d_inode; | |
283 | unsigned long user_addr = (unsigned long)iov->iov_base; | |
284 | size_t count = iov->iov_len; | |
285 | size_t rsize = NFS_SERVER(inode)->rsize; | |
286 | struct rpc_task *task; | |
287 | struct rpc_message msg = { | |
288 | .rpc_cred = ctx->cred, | |
289 | }; | |
290 | struct rpc_task_setup task_setup_data = { | |
291 | .rpc_client = NFS_CLIENT(inode), | |
292 | .rpc_message = &msg, | |
293 | .callback_ops = &nfs_read_direct_ops, | |
294 | .workqueue = nfsiod_workqueue, | |
295 | .flags = RPC_TASK_ASYNC, | |
296 | }; | |
297 | unsigned int pgbase; | |
298 | int result; | |
299 | ssize_t started = 0; | |
300 | ||
301 | do { | |
302 | struct nfs_read_data *data; | |
303 | size_t bytes; | |
304 | ||
305 | pgbase = user_addr & ~PAGE_MASK; | |
306 | bytes = min(rsize,count); | |
307 | ||
308 | result = -ENOMEM; | |
309 | data = nfs_readdata_alloc(nfs_page_array_len(pgbase, bytes)); | |
310 | if (unlikely(!data)) | |
311 | break; | |
312 | ||
313 | down_read(¤t->mm->mmap_sem); | |
314 | result = get_user_pages(current, current->mm, user_addr, | |
315 | data->npages, 1, 0, data->pagevec, NULL); | |
316 | up_read(¤t->mm->mmap_sem); | |
317 | if (result < 0) { | |
318 | nfs_readdata_free(data); | |
319 | break; | |
320 | } | |
321 | if ((unsigned)result < data->npages) { | |
322 | bytes = result * PAGE_SIZE; | |
323 | if (bytes <= pgbase) { | |
324 | nfs_direct_release_pages(data->pagevec, result); | |
325 | nfs_readdata_free(data); | |
326 | break; | |
327 | } | |
328 | bytes -= pgbase; | |
329 | data->npages = result; | |
330 | } | |
331 | ||
332 | get_dreq(dreq); | |
333 | ||
334 | data->req = (struct nfs_page *) dreq; | |
335 | data->inode = inode; | |
336 | data->cred = msg.rpc_cred; | |
337 | data->args.fh = NFS_FH(inode); | |
338 | data->args.context = ctx; | |
339 | data->args.offset = pos; | |
340 | data->args.pgbase = pgbase; | |
341 | data->args.pages = data->pagevec; | |
342 | data->args.count = bytes; | |
343 | data->res.fattr = &data->fattr; | |
344 | data->res.eof = 0; | |
345 | data->res.count = bytes; | |
346 | nfs_fattr_init(&data->fattr); | |
347 | msg.rpc_argp = &data->args; | |
348 | msg.rpc_resp = &data->res; | |
349 | ||
350 | task_setup_data.task = &data->task; | |
351 | task_setup_data.callback_data = data; | |
352 | NFS_PROTO(inode)->read_setup(data, &msg); | |
353 | ||
354 | task = rpc_run_task(&task_setup_data); | |
355 | if (IS_ERR(task)) | |
356 | break; | |
357 | rpc_put_task(task); | |
358 | ||
359 | dprintk("NFS: %5u initiated direct read call " | |
360 | "(req %s/%Ld, %zu bytes @ offset %Lu)\n", | |
361 | data->task.tk_pid, | |
362 | inode->i_sb->s_id, | |
363 | (long long)NFS_FILEID(inode), | |
364 | bytes, | |
365 | (unsigned long long)data->args.offset); | |
366 | ||
367 | started += bytes; | |
368 | user_addr += bytes; | |
369 | pos += bytes; | |
370 | /* FIXME: Remove this unnecessary math from final patch */ | |
371 | pgbase += bytes; | |
372 | pgbase &= ~PAGE_MASK; | |
373 | BUG_ON(pgbase != (user_addr & ~PAGE_MASK)); | |
374 | ||
375 | count -= bytes; | |
376 | } while (count != 0); | |
377 | ||
378 | if (started) | |
379 | return started; | |
380 | return result < 0 ? (ssize_t) result : -EFAULT; | |
381 | } | |
382 | ||
383 | static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq, | |
384 | const struct iovec *iov, | |
385 | unsigned long nr_segs, | |
386 | loff_t pos) | |
387 | { | |
388 | ssize_t result = -EINVAL; | |
389 | size_t requested_bytes = 0; | |
390 | unsigned long seg; | |
391 | ||
392 | get_dreq(dreq); | |
393 | ||
394 | for (seg = 0; seg < nr_segs; seg++) { | |
395 | const struct iovec *vec = &iov[seg]; | |
396 | result = nfs_direct_read_schedule_segment(dreq, vec, pos); | |
397 | if (result < 0) | |
398 | break; | |
399 | requested_bytes += result; | |
400 | if ((size_t)result < vec->iov_len) | |
401 | break; | |
402 | pos += vec->iov_len; | |
403 | } | |
404 | ||
405 | if (put_dreq(dreq)) | |
406 | nfs_direct_complete(dreq); | |
407 | ||
408 | if (requested_bytes != 0) | |
409 | return 0; | |
410 | ||
411 | if (result < 0) | |
412 | return result; | |
413 | return -EIO; | |
414 | } | |
415 | ||
416 | static ssize_t nfs_direct_read(struct kiocb *iocb, const struct iovec *iov, | |
417 | unsigned long nr_segs, loff_t pos) | |
418 | { | |
419 | ssize_t result = 0; | |
420 | struct inode *inode = iocb->ki_filp->f_mapping->host; | |
421 | struct nfs_direct_req *dreq; | |
422 | ||
423 | dreq = nfs_direct_req_alloc(); | |
424 | if (!dreq) | |
425 | return -ENOMEM; | |
426 | ||
427 | dreq->inode = inode; | |
428 | dreq->ctx = get_nfs_open_context(nfs_file_open_context(iocb->ki_filp)); | |
429 | if (!is_sync_kiocb(iocb)) | |
430 | dreq->iocb = iocb; | |
431 | ||
432 | result = nfs_direct_read_schedule_iovec(dreq, iov, nr_segs, pos); | |
433 | if (!result) | |
434 | result = nfs_direct_wait(dreq); | |
435 | nfs_direct_req_release(dreq); | |
436 | ||
437 | return result; | |
438 | } | |
439 | ||
440 | static void nfs_direct_free_writedata(struct nfs_direct_req *dreq) | |
441 | { | |
442 | while (!list_empty(&dreq->rewrite_list)) { | |
443 | struct nfs_write_data *data = list_entry(dreq->rewrite_list.next, struct nfs_write_data, pages); | |
444 | list_del(&data->pages); | |
445 | nfs_direct_release_pages(data->pagevec, data->npages); | |
446 | nfs_writedata_free(data); | |
447 | } | |
448 | } | |
449 | ||
450 | #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4) | |
451 | static void nfs_direct_write_reschedule(struct nfs_direct_req *dreq) | |
452 | { | |
453 | struct inode *inode = dreq->inode; | |
454 | struct list_head *p; | |
455 | struct nfs_write_data *data; | |
456 | struct rpc_task *task; | |
457 | struct rpc_message msg = { | |
458 | .rpc_cred = dreq->ctx->cred, | |
459 | }; | |
460 | struct rpc_task_setup task_setup_data = { | |
461 | .rpc_client = NFS_CLIENT(inode), | |
462 | .rpc_message = &msg, | |
463 | .callback_ops = &nfs_write_direct_ops, | |
464 | .workqueue = nfsiod_workqueue, | |
465 | .flags = RPC_TASK_ASYNC, | |
466 | }; | |
467 | ||
468 | dreq->count = 0; | |
469 | get_dreq(dreq); | |
470 | ||
471 | list_for_each(p, &dreq->rewrite_list) { | |
472 | data = list_entry(p, struct nfs_write_data, pages); | |
473 | ||
474 | get_dreq(dreq); | |
475 | ||
476 | /* Use stable writes */ | |
477 | data->args.stable = NFS_FILE_SYNC; | |
478 | ||
479 | /* | |
480 | * Reset data->res. | |
481 | */ | |
482 | nfs_fattr_init(&data->fattr); | |
483 | data->res.count = data->args.count; | |
484 | memset(&data->verf, 0, sizeof(data->verf)); | |
485 | ||
486 | /* | |
487 | * Reuse data->task; data->args should not have changed | |
488 | * since the original request was sent. | |
489 | */ | |
490 | task_setup_data.task = &data->task; | |
491 | task_setup_data.callback_data = data; | |
492 | msg.rpc_argp = &data->args; | |
493 | msg.rpc_resp = &data->res; | |
494 | NFS_PROTO(inode)->write_setup(data, &msg); | |
495 | ||
496 | /* | |
497 | * We're called via an RPC callback, so BKL is already held. | |
498 | */ | |
499 | task = rpc_run_task(&task_setup_data); | |
500 | if (!IS_ERR(task)) | |
501 | rpc_put_task(task); | |
502 | ||
503 | dprintk("NFS: %5u rescheduled direct write call (req %s/%Ld, %u bytes @ offset %Lu)\n", | |
504 | data->task.tk_pid, | |
505 | inode->i_sb->s_id, | |
506 | (long long)NFS_FILEID(inode), | |
507 | data->args.count, | |
508 | (unsigned long long)data->args.offset); | |
509 | } | |
510 | ||
511 | if (put_dreq(dreq)) | |
512 | nfs_direct_write_complete(dreq, inode); | |
513 | } | |
514 | ||
515 | static void nfs_direct_commit_result(struct rpc_task *task, void *calldata) | |
516 | { | |
517 | struct nfs_write_data *data = calldata; | |
518 | ||
519 | /* Call the NFS version-specific code */ | |
520 | NFS_PROTO(data->inode)->commit_done(task, data); | |
521 | } | |
522 | ||
523 | static void nfs_direct_commit_release(void *calldata) | |
524 | { | |
525 | struct nfs_write_data *data = calldata; | |
526 | struct nfs_direct_req *dreq = (struct nfs_direct_req *) data->req; | |
527 | int status = data->task.tk_status; | |
528 | ||
529 | if (status < 0) { | |
530 | dprintk("NFS: %5u commit failed with error %d.\n", | |
531 | data->task.tk_pid, status); | |
532 | dreq->flags = NFS_ODIRECT_RESCHED_WRITES; | |
533 | } else if (memcmp(&dreq->verf, &data->verf, sizeof(data->verf))) { | |
534 | dprintk("NFS: %5u commit verify failed\n", data->task.tk_pid); | |
535 | dreq->flags = NFS_ODIRECT_RESCHED_WRITES; | |
536 | } | |
537 | ||
538 | dprintk("NFS: %5u commit returned %d\n", data->task.tk_pid, status); | |
539 | nfs_direct_write_complete(dreq, data->inode); | |
540 | nfs_commit_free(data); | |
541 | } | |
542 | ||
543 | static const struct rpc_call_ops nfs_commit_direct_ops = { | |
544 | #if defined(CONFIG_NFS_V4_1) | |
545 | .rpc_call_prepare = nfs_write_prepare, | |
546 | #endif /* CONFIG_NFS_V4_1 */ | |
547 | .rpc_call_done = nfs_direct_commit_result, | |
548 | .rpc_release = nfs_direct_commit_release, | |
549 | }; | |
550 | ||
551 | static void nfs_direct_commit_schedule(struct nfs_direct_req *dreq) | |
552 | { | |
553 | struct nfs_write_data *data = dreq->commit_data; | |
554 | struct rpc_task *task; | |
555 | struct rpc_message msg = { | |
556 | .rpc_argp = &data->args, | |
557 | .rpc_resp = &data->res, | |
558 | .rpc_cred = dreq->ctx->cred, | |
559 | }; | |
560 | struct rpc_task_setup task_setup_data = { | |
561 | .task = &data->task, | |
562 | .rpc_client = NFS_CLIENT(dreq->inode), | |
563 | .rpc_message = &msg, | |
564 | .callback_ops = &nfs_commit_direct_ops, | |
565 | .callback_data = data, | |
566 | .workqueue = nfsiod_workqueue, | |
567 | .flags = RPC_TASK_ASYNC, | |
568 | }; | |
569 | ||
570 | data->inode = dreq->inode; | |
571 | data->cred = msg.rpc_cred; | |
572 | ||
573 | data->args.fh = NFS_FH(data->inode); | |
574 | data->args.offset = 0; | |
575 | data->args.count = 0; | |
576 | data->args.context = dreq->ctx; | |
577 | data->res.count = 0; | |
578 | data->res.fattr = &data->fattr; | |
579 | data->res.verf = &data->verf; | |
580 | nfs_fattr_init(&data->fattr); | |
581 | ||
582 | NFS_PROTO(data->inode)->commit_setup(data, &msg); | |
583 | ||
584 | /* Note: task.tk_ops->rpc_release will free dreq->commit_data */ | |
585 | dreq->commit_data = NULL; | |
586 | ||
587 | dprintk("NFS: %5u initiated commit call\n", data->task.tk_pid); | |
588 | ||
589 | task = rpc_run_task(&task_setup_data); | |
590 | if (!IS_ERR(task)) | |
591 | rpc_put_task(task); | |
592 | } | |
593 | ||
594 | static void nfs_direct_write_complete(struct nfs_direct_req *dreq, struct inode *inode) | |
595 | { | |
596 | int flags = dreq->flags; | |
597 | ||
598 | dreq->flags = 0; | |
599 | switch (flags) { | |
600 | case NFS_ODIRECT_DO_COMMIT: | |
601 | nfs_direct_commit_schedule(dreq); | |
602 | break; | |
603 | case NFS_ODIRECT_RESCHED_WRITES: | |
604 | nfs_direct_write_reschedule(dreq); | |
605 | break; | |
606 | default: | |
607 | if (dreq->commit_data != NULL) | |
608 | nfs_commit_free(dreq->commit_data); | |
609 | nfs_direct_free_writedata(dreq); | |
610 | nfs_zap_mapping(inode, inode->i_mapping); | |
611 | nfs_direct_complete(dreq); | |
612 | } | |
613 | } | |
614 | ||
615 | static void nfs_alloc_commit_data(struct nfs_direct_req *dreq) | |
616 | { | |
617 | dreq->commit_data = nfs_commitdata_alloc(); | |
618 | if (dreq->commit_data != NULL) | |
619 | dreq->commit_data->req = (struct nfs_page *) dreq; | |
620 | } | |
621 | #else | |
622 | static inline void nfs_alloc_commit_data(struct nfs_direct_req *dreq) | |
623 | { | |
624 | dreq->commit_data = NULL; | |
625 | } | |
626 | ||
627 | static void nfs_direct_write_complete(struct nfs_direct_req *dreq, struct inode *inode) | |
628 | { | |
629 | nfs_direct_free_writedata(dreq); | |
630 | nfs_zap_mapping(inode, inode->i_mapping); | |
631 | nfs_direct_complete(dreq); | |
632 | } | |
633 | #endif | |
634 | ||
635 | static void nfs_direct_write_result(struct rpc_task *task, void *calldata) | |
636 | { | |
637 | struct nfs_write_data *data = calldata; | |
638 | ||
639 | if (nfs_writeback_done(task, data) != 0) | |
640 | return; | |
641 | } | |
642 | ||
643 | /* | |
644 | * NB: Return the value of the first error return code. Subsequent | |
645 | * errors after the first one are ignored. | |
646 | */ | |
647 | static void nfs_direct_write_release(void *calldata) | |
648 | { | |
649 | struct nfs_write_data *data = calldata; | |
650 | struct nfs_direct_req *dreq = (struct nfs_direct_req *) data->req; | |
651 | int status = data->task.tk_status; | |
652 | ||
653 | spin_lock(&dreq->lock); | |
654 | ||
655 | if (unlikely(status < 0)) { | |
656 | /* An error has occurred, so we should not commit */ | |
657 | dreq->flags = 0; | |
658 | dreq->error = status; | |
659 | } | |
660 | if (unlikely(dreq->error != 0)) | |
661 | goto out_unlock; | |
662 | ||
663 | dreq->count += data->res.count; | |
664 | ||
665 | if (data->res.verf->committed != NFS_FILE_SYNC) { | |
666 | switch (dreq->flags) { | |
667 | case 0: | |
668 | memcpy(&dreq->verf, &data->verf, sizeof(dreq->verf)); | |
669 | dreq->flags = NFS_ODIRECT_DO_COMMIT; | |
670 | break; | |
671 | case NFS_ODIRECT_DO_COMMIT: | |
672 | if (memcmp(&dreq->verf, &data->verf, sizeof(dreq->verf))) { | |
673 | dprintk("NFS: %5u write verify failed\n", data->task.tk_pid); | |
674 | dreq->flags = NFS_ODIRECT_RESCHED_WRITES; | |
675 | } | |
676 | } | |
677 | } | |
678 | out_unlock: | |
679 | spin_unlock(&dreq->lock); | |
680 | ||
681 | if (put_dreq(dreq)) | |
682 | nfs_direct_write_complete(dreq, data->inode); | |
683 | } | |
684 | ||
685 | static const struct rpc_call_ops nfs_write_direct_ops = { | |
686 | #if defined(CONFIG_NFS_V4_1) | |
687 | .rpc_call_prepare = nfs_write_prepare, | |
688 | #endif /* CONFIG_NFS_V4_1 */ | |
689 | .rpc_call_done = nfs_direct_write_result, | |
690 | .rpc_release = nfs_direct_write_release, | |
691 | }; | |
692 | ||
693 | /* | |
694 | * For each wsize'd chunk of the user's buffer, dispatch an NFS WRITE | |
695 | * operation. If nfs_writedata_alloc() or get_user_pages() fails, | |
696 | * bail and stop sending more writes. Write length accounting is | |
697 | * handled automatically by nfs_direct_write_result(). Otherwise, if | |
698 | * no requests have been sent, just return an error. | |
699 | */ | |
700 | static ssize_t nfs_direct_write_schedule_segment(struct nfs_direct_req *dreq, | |
701 | const struct iovec *iov, | |
702 | loff_t pos, int sync) | |
703 | { | |
704 | struct nfs_open_context *ctx = dreq->ctx; | |
705 | struct inode *inode = ctx->path.dentry->d_inode; | |
706 | unsigned long user_addr = (unsigned long)iov->iov_base; | |
707 | size_t count = iov->iov_len; | |
708 | struct rpc_task *task; | |
709 | struct rpc_message msg = { | |
710 | .rpc_cred = ctx->cred, | |
711 | }; | |
712 | struct rpc_task_setup task_setup_data = { | |
713 | .rpc_client = NFS_CLIENT(inode), | |
714 | .rpc_message = &msg, | |
715 | .callback_ops = &nfs_write_direct_ops, | |
716 | .workqueue = nfsiod_workqueue, | |
717 | .flags = RPC_TASK_ASYNC, | |
718 | }; | |
719 | size_t wsize = NFS_SERVER(inode)->wsize; | |
720 | unsigned int pgbase; | |
721 | int result; | |
722 | ssize_t started = 0; | |
723 | ||
724 | do { | |
725 | struct nfs_write_data *data; | |
726 | size_t bytes; | |
727 | ||
728 | pgbase = user_addr & ~PAGE_MASK; | |
729 | bytes = min(wsize,count); | |
730 | ||
731 | result = -ENOMEM; | |
732 | data = nfs_writedata_alloc(nfs_page_array_len(pgbase, bytes)); | |
733 | if (unlikely(!data)) | |
734 | break; | |
735 | ||
736 | down_read(¤t->mm->mmap_sem); | |
737 | result = get_user_pages(current, current->mm, user_addr, | |
738 | data->npages, 0, 0, data->pagevec, NULL); | |
739 | up_read(¤t->mm->mmap_sem); | |
740 | if (result < 0) { | |
741 | nfs_writedata_free(data); | |
742 | break; | |
743 | } | |
744 | if ((unsigned)result < data->npages) { | |
745 | bytes = result * PAGE_SIZE; | |
746 | if (bytes <= pgbase) { | |
747 | nfs_direct_release_pages(data->pagevec, result); | |
748 | nfs_writedata_free(data); | |
749 | break; | |
750 | } | |
751 | bytes -= pgbase; | |
752 | data->npages = result; | |
753 | } | |
754 | ||
755 | get_dreq(dreq); | |
756 | ||
757 | list_move_tail(&data->pages, &dreq->rewrite_list); | |
758 | ||
759 | data->req = (struct nfs_page *) dreq; | |
760 | data->inode = inode; | |
761 | data->cred = msg.rpc_cred; | |
762 | data->args.fh = NFS_FH(inode); | |
763 | data->args.context = ctx; | |
764 | data->args.offset = pos; | |
765 | data->args.pgbase = pgbase; | |
766 | data->args.pages = data->pagevec; | |
767 | data->args.count = bytes; | |
768 | data->args.stable = sync; | |
769 | data->res.fattr = &data->fattr; | |
770 | data->res.count = bytes; | |
771 | data->res.verf = &data->verf; | |
772 | nfs_fattr_init(&data->fattr); | |
773 | ||
774 | task_setup_data.task = &data->task; | |
775 | task_setup_data.callback_data = data; | |
776 | msg.rpc_argp = &data->args; | |
777 | msg.rpc_resp = &data->res; | |
778 | NFS_PROTO(inode)->write_setup(data, &msg); | |
779 | ||
780 | task = rpc_run_task(&task_setup_data); | |
781 | if (IS_ERR(task)) | |
782 | break; | |
783 | rpc_put_task(task); | |
784 | ||
785 | dprintk("NFS: %5u initiated direct write call " | |
786 | "(req %s/%Ld, %zu bytes @ offset %Lu)\n", | |
787 | data->task.tk_pid, | |
788 | inode->i_sb->s_id, | |
789 | (long long)NFS_FILEID(inode), | |
790 | bytes, | |
791 | (unsigned long long)data->args.offset); | |
792 | ||
793 | started += bytes; | |
794 | user_addr += bytes; | |
795 | pos += bytes; | |
796 | ||
797 | /* FIXME: Remove this useless math from the final patch */ | |
798 | pgbase += bytes; | |
799 | pgbase &= ~PAGE_MASK; | |
800 | BUG_ON(pgbase != (user_addr & ~PAGE_MASK)); | |
801 | ||
802 | count -= bytes; | |
803 | } while (count != 0); | |
804 | ||
805 | if (started) | |
806 | return started; | |
807 | return result < 0 ? (ssize_t) result : -EFAULT; | |
808 | } | |
809 | ||
810 | static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq, | |
811 | const struct iovec *iov, | |
812 | unsigned long nr_segs, | |
813 | loff_t pos, int sync) | |
814 | { | |
815 | ssize_t result = 0; | |
816 | size_t requested_bytes = 0; | |
817 | unsigned long seg; | |
818 | ||
819 | get_dreq(dreq); | |
820 | ||
821 | for (seg = 0; seg < nr_segs; seg++) { | |
822 | const struct iovec *vec = &iov[seg]; | |
823 | result = nfs_direct_write_schedule_segment(dreq, vec, | |
824 | pos, sync); | |
825 | if (result < 0) | |
826 | break; | |
827 | requested_bytes += result; | |
828 | if ((size_t)result < vec->iov_len) | |
829 | break; | |
830 | pos += vec->iov_len; | |
831 | } | |
832 | ||
833 | if (put_dreq(dreq)) | |
834 | nfs_direct_write_complete(dreq, dreq->inode); | |
835 | ||
836 | if (requested_bytes != 0) | |
837 | return 0; | |
838 | ||
839 | if (result < 0) | |
840 | return result; | |
841 | return -EIO; | |
842 | } | |
843 | ||
844 | static ssize_t nfs_direct_write(struct kiocb *iocb, const struct iovec *iov, | |
845 | unsigned long nr_segs, loff_t pos, | |
846 | size_t count) | |
847 | { | |
848 | ssize_t result = 0; | |
849 | struct inode *inode = iocb->ki_filp->f_mapping->host; | |
850 | struct nfs_direct_req *dreq; | |
851 | size_t wsize = NFS_SERVER(inode)->wsize; | |
852 | int sync = NFS_UNSTABLE; | |
853 | ||
854 | dreq = nfs_direct_req_alloc(); | |
855 | if (!dreq) | |
856 | return -ENOMEM; | |
857 | nfs_alloc_commit_data(dreq); | |
858 | ||
859 | if (dreq->commit_data == NULL || count < wsize) | |
860 | sync = NFS_FILE_SYNC; | |
861 | ||
862 | dreq->inode = inode; | |
863 | dreq->ctx = get_nfs_open_context(nfs_file_open_context(iocb->ki_filp)); | |
864 | if (!is_sync_kiocb(iocb)) | |
865 | dreq->iocb = iocb; | |
866 | ||
867 | result = nfs_direct_write_schedule_iovec(dreq, iov, nr_segs, pos, sync); | |
868 | if (!result) | |
869 | result = nfs_direct_wait(dreq); | |
870 | nfs_direct_req_release(dreq); | |
871 | ||
872 | return result; | |
873 | } | |
874 | ||
875 | /** | |
876 | * nfs_file_direct_read - file direct read operation for NFS files | |
877 | * @iocb: target I/O control block | |
878 | * @iov: vector of user buffers into which to read data | |
879 | * @nr_segs: size of iov vector | |
880 | * @pos: byte offset in file where reading starts | |
881 | * | |
882 | * We use this function for direct reads instead of calling | |
883 | * generic_file_aio_read() in order to avoid gfar's check to see if | |
884 | * the request starts before the end of the file. For that check | |
885 | * to work, we must generate a GETATTR before each direct read, and | |
886 | * even then there is a window between the GETATTR and the subsequent | |
887 | * READ where the file size could change. Our preference is simply | |
888 | * to do all reads the application wants, and the server will take | |
889 | * care of managing the end of file boundary. | |
890 | * | |
891 | * This function also eliminates unnecessarily updating the file's | |
892 | * atime locally, as the NFS server sets the file's atime, and this | |
893 | * client must read the updated atime from the server back into its | |
894 | * cache. | |
895 | */ | |
896 | ssize_t nfs_file_direct_read(struct kiocb *iocb, const struct iovec *iov, | |
897 | unsigned long nr_segs, loff_t pos) | |
898 | { | |
899 | ssize_t retval = -EINVAL; | |
900 | struct file *file = iocb->ki_filp; | |
901 | struct address_space *mapping = file->f_mapping; | |
902 | size_t count; | |
903 | ||
904 | count = iov_length(iov, nr_segs); | |
905 | nfs_add_stats(mapping->host, NFSIOS_DIRECTREADBYTES, count); | |
906 | ||
907 | dfprintk(FILE, "NFS: direct read(%s/%s, %zd@%Ld)\n", | |
908 | file->f_path.dentry->d_parent->d_name.name, | |
909 | file->f_path.dentry->d_name.name, | |
910 | count, (long long) pos); | |
911 | ||
912 | retval = 0; | |
913 | if (!count) | |
914 | goto out; | |
915 | ||
916 | retval = nfs_sync_mapping(mapping); | |
917 | if (retval) | |
918 | goto out; | |
919 | ||
920 | retval = nfs_direct_read(iocb, iov, nr_segs, pos); | |
921 | if (retval > 0) | |
922 | iocb->ki_pos = pos + retval; | |
923 | ||
924 | out: | |
925 | return retval; | |
926 | } | |
927 | ||
928 | /** | |
929 | * nfs_file_direct_write - file direct write operation for NFS files | |
930 | * @iocb: target I/O control block | |
931 | * @iov: vector of user buffers from which to write data | |
932 | * @nr_segs: size of iov vector | |
933 | * @pos: byte offset in file where writing starts | |
934 | * | |
935 | * We use this function for direct writes instead of calling | |
936 | * generic_file_aio_write() in order to avoid taking the inode | |
937 | * semaphore and updating the i_size. The NFS server will set | |
938 | * the new i_size and this client must read the updated size | |
939 | * back into its cache. We let the server do generic write | |
940 | * parameter checking and report problems. | |
941 | * | |
942 | * We eliminate local atime updates, see direct read above. | |
943 | * | |
944 | * We avoid unnecessary page cache invalidations for normal cached | |
945 | * readers of this file. | |
946 | * | |
947 | * Note that O_APPEND is not supported for NFS direct writes, as there | |
948 | * is no atomic O_APPEND write facility in the NFS protocol. | |
949 | */ | |
950 | ssize_t nfs_file_direct_write(struct kiocb *iocb, const struct iovec *iov, | |
951 | unsigned long nr_segs, loff_t pos) | |
952 | { | |
953 | ssize_t retval = -EINVAL; | |
954 | struct file *file = iocb->ki_filp; | |
955 | struct address_space *mapping = file->f_mapping; | |
956 | size_t count; | |
957 | ||
958 | count = iov_length(iov, nr_segs); | |
959 | nfs_add_stats(mapping->host, NFSIOS_DIRECTWRITTENBYTES, count); | |
960 | ||
961 | dfprintk(FILE, "NFS: direct write(%s/%s, %zd@%Ld)\n", | |
962 | file->f_path.dentry->d_parent->d_name.name, | |
963 | file->f_path.dentry->d_name.name, | |
964 | count, (long long) pos); | |
965 | ||
966 | retval = generic_write_checks(file, &pos, &count, 0); | |
967 | if (retval) | |
968 | goto out; | |
969 | ||
970 | retval = -EINVAL; | |
971 | if ((ssize_t) count < 0) | |
972 | goto out; | |
973 | retval = 0; | |
974 | if (!count) | |
975 | goto out; | |
976 | ||
977 | retval = nfs_sync_mapping(mapping); | |
978 | if (retval) | |
979 | goto out; | |
980 | ||
981 | retval = nfs_direct_write(iocb, iov, nr_segs, pos, count); | |
982 | ||
983 | if (retval > 0) | |
984 | iocb->ki_pos = pos + retval; | |
985 | ||
986 | out: | |
987 | return retval; | |
988 | } | |
989 | ||
990 | /** | |
991 | * nfs_init_directcache - create a slab cache for nfs_direct_req structures | |
992 | * | |
993 | */ | |
994 | int __init nfs_init_directcache(void) | |
995 | { | |
996 | nfs_direct_cachep = kmem_cache_create("nfs_direct_cache", | |
997 | sizeof(struct nfs_direct_req), | |
998 | 0, (SLAB_RECLAIM_ACCOUNT| | |
999 | SLAB_MEM_SPREAD), | |
1000 | NULL); | |
1001 | if (nfs_direct_cachep == NULL) | |
1002 | return -ENOMEM; | |
1003 | ||
1004 | return 0; | |
1005 | } | |
1006 | ||
1007 | /** | |
1008 | * nfs_destroy_directcache - destroy the slab cache for nfs_direct_req structures | |
1009 | * | |
1010 | */ | |
1011 | void nfs_destroy_directcache(void) | |
1012 | { | |
1013 | kmem_cache_destroy(nfs_direct_cachep); | |
1014 | } |