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1/*
2 * linux/fs/nfs/pagelist.c
3 *
4 * A set of helper functions for managing NFS read and write requests.
5 * The main purpose of these routines is to provide support for the
6 * coalescing of several requests into a single RPC call.
7 *
8 * Copyright 2000, 2001 (c) Trond Myklebust <trond.myklebust@fys.uio.no>
9 *
10 */
11
12#include <linux/slab.h>
13#include <linux/file.h>
14#include <linux/sched.h>
15#include <linux/sunrpc/clnt.h>
16#include <linux/nfs.h>
17#include <linux/nfs3.h>
18#include <linux/nfs4.h>
19#include <linux/nfs_page.h>
20#include <linux/nfs_fs.h>
21#include <linux/nfs_mount.h>
22#include <linux/export.h>
23
24#include "internal.h"
25#include "pnfs.h"
26
27#define NFSDBG_FACILITY NFSDBG_PAGECACHE
28
29static struct kmem_cache *nfs_page_cachep;
30static const struct rpc_call_ops nfs_pgio_common_ops;
31
32struct nfs_pgio_mirror *
33nfs_pgio_current_mirror(struct nfs_pageio_descriptor *desc)
34{
35 return nfs_pgio_has_mirroring(desc) ?
36 &desc->pg_mirrors[desc->pg_mirror_idx] :
37 &desc->pg_mirrors[0];
38}
39EXPORT_SYMBOL_GPL(nfs_pgio_current_mirror);
40
41void nfs_pgheader_init(struct nfs_pageio_descriptor *desc,
42 struct nfs_pgio_header *hdr,
43 void (*release)(struct nfs_pgio_header *hdr))
44{
45 struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
46
47
48 hdr->req = nfs_list_entry(mirror->pg_list.next);
49 hdr->inode = desc->pg_inode;
50 hdr->cred = hdr->req->wb_context->cred;
51 hdr->io_start = req_offset(hdr->req);
52 hdr->good_bytes = mirror->pg_count;
53 hdr->io_completion = desc->pg_io_completion;
54 hdr->dreq = desc->pg_dreq;
55 hdr->release = release;
56 hdr->completion_ops = desc->pg_completion_ops;
57 if (hdr->completion_ops->init_hdr)
58 hdr->completion_ops->init_hdr(hdr);
59
60 hdr->pgio_mirror_idx = desc->pg_mirror_idx;
61}
62EXPORT_SYMBOL_GPL(nfs_pgheader_init);
63
64void nfs_set_pgio_error(struct nfs_pgio_header *hdr, int error, loff_t pos)
65{
66 spin_lock(&hdr->lock);
67 if (!test_and_set_bit(NFS_IOHDR_ERROR, &hdr->flags)
68 || pos < hdr->io_start + hdr->good_bytes) {
69 clear_bit(NFS_IOHDR_EOF, &hdr->flags);
70 hdr->good_bytes = pos - hdr->io_start;
71 hdr->error = error;
72 }
73 spin_unlock(&hdr->lock);
74}
75
76static inline struct nfs_page *
77nfs_page_alloc(void)
78{
79 struct nfs_page *p = kmem_cache_zalloc(nfs_page_cachep, GFP_NOIO);
80 if (p)
81 INIT_LIST_HEAD(&p->wb_list);
82 return p;
83}
84
85static inline void
86nfs_page_free(struct nfs_page *p)
87{
88 kmem_cache_free(nfs_page_cachep, p);
89}
90
91/**
92 * nfs_iocounter_wait - wait for i/o to complete
93 * @l_ctx: nfs_lock_context with io_counter to use
94 *
95 * returns -ERESTARTSYS if interrupted by a fatal signal.
96 * Otherwise returns 0 once the io_count hits 0.
97 */
98int
99nfs_iocounter_wait(struct nfs_lock_context *l_ctx)
100{
101 return wait_var_event_killable(&l_ctx->io_count,
102 !atomic_read(&l_ctx->io_count));
103}
104
105/**
106 * nfs_async_iocounter_wait - wait on a rpc_waitqueue for I/O
107 * to complete
108 * @task: the rpc_task that should wait
109 * @l_ctx: nfs_lock_context with io_counter to check
110 *
111 * Returns true if there is outstanding I/O to wait on and the
112 * task has been put to sleep.
113 */
114bool
115nfs_async_iocounter_wait(struct rpc_task *task, struct nfs_lock_context *l_ctx)
116{
117 struct inode *inode = d_inode(l_ctx->open_context->dentry);
118 bool ret = false;
119
120 if (atomic_read(&l_ctx->io_count) > 0) {
121 rpc_sleep_on(&NFS_SERVER(inode)->uoc_rpcwaitq, task, NULL);
122 ret = true;
123 }
124
125 if (atomic_read(&l_ctx->io_count) == 0) {
126 rpc_wake_up_queued_task(&NFS_SERVER(inode)->uoc_rpcwaitq, task);
127 ret = false;
128 }
129
130 return ret;
131}
132EXPORT_SYMBOL_GPL(nfs_async_iocounter_wait);
133
134/*
135 * nfs_page_group_lock - lock the head of the page group
136 * @req - request in group that is to be locked
137 *
138 * this lock must be held when traversing or modifying the page
139 * group list
140 *
141 * return 0 on success, < 0 on error
142 */
143int
144nfs_page_group_lock(struct nfs_page *req)
145{
146 struct nfs_page *head = req->wb_head;
147
148 WARN_ON_ONCE(head != head->wb_head);
149
150 if (!test_and_set_bit(PG_HEADLOCK, &head->wb_flags))
151 return 0;
152
153 set_bit(PG_CONTENDED1, &head->wb_flags);
154 smp_mb__after_atomic();
155 return wait_on_bit_lock(&head->wb_flags, PG_HEADLOCK,
156 TASK_UNINTERRUPTIBLE);
157}
158
159/*
160 * nfs_page_group_unlock - unlock the head of the page group
161 * @req - request in group that is to be unlocked
162 */
163void
164nfs_page_group_unlock(struct nfs_page *req)
165{
166 struct nfs_page *head = req->wb_head;
167
168 WARN_ON_ONCE(head != head->wb_head);
169
170 smp_mb__before_atomic();
171 clear_bit(PG_HEADLOCK, &head->wb_flags);
172 smp_mb__after_atomic();
173 if (!test_bit(PG_CONTENDED1, &head->wb_flags))
174 return;
175 wake_up_bit(&head->wb_flags, PG_HEADLOCK);
176}
177
178/*
179 * nfs_page_group_sync_on_bit_locked
180 *
181 * must be called with page group lock held
182 */
183static bool
184nfs_page_group_sync_on_bit_locked(struct nfs_page *req, unsigned int bit)
185{
186 struct nfs_page *head = req->wb_head;
187 struct nfs_page *tmp;
188
189 WARN_ON_ONCE(!test_bit(PG_HEADLOCK, &head->wb_flags));
190 WARN_ON_ONCE(test_and_set_bit(bit, &req->wb_flags));
191
192 tmp = req->wb_this_page;
193 while (tmp != req) {
194 if (!test_bit(bit, &tmp->wb_flags))
195 return false;
196 tmp = tmp->wb_this_page;
197 }
198
199 /* true! reset all bits */
200 tmp = req;
201 do {
202 clear_bit(bit, &tmp->wb_flags);
203 tmp = tmp->wb_this_page;
204 } while (tmp != req);
205
206 return true;
207}
208
209/*
210 * nfs_page_group_sync_on_bit - set bit on current request, but only
211 * return true if the bit is set for all requests in page group
212 * @req - request in page group
213 * @bit - PG_* bit that is used to sync page group
214 */
215bool nfs_page_group_sync_on_bit(struct nfs_page *req, unsigned int bit)
216{
217 bool ret;
218
219 nfs_page_group_lock(req);
220 ret = nfs_page_group_sync_on_bit_locked(req, bit);
221 nfs_page_group_unlock(req);
222
223 return ret;
224}
225
226/*
227 * nfs_page_group_init - Initialize the page group linkage for @req
228 * @req - a new nfs request
229 * @prev - the previous request in page group, or NULL if @req is the first
230 * or only request in the group (the head).
231 */
232static inline void
233nfs_page_group_init(struct nfs_page *req, struct nfs_page *prev)
234{
235 struct inode *inode;
236 WARN_ON_ONCE(prev == req);
237
238 if (!prev) {
239 /* a head request */
240 req->wb_head = req;
241 req->wb_this_page = req;
242 } else {
243 /* a subrequest */
244 WARN_ON_ONCE(prev->wb_this_page != prev->wb_head);
245 WARN_ON_ONCE(!test_bit(PG_HEADLOCK, &prev->wb_head->wb_flags));
246 req->wb_head = prev->wb_head;
247 req->wb_this_page = prev->wb_this_page;
248 prev->wb_this_page = req;
249
250 /* All subrequests take a ref on the head request until
251 * nfs_page_group_destroy is called */
252 kref_get(&req->wb_head->wb_kref);
253
254 /* grab extra ref and bump the request count if head request
255 * has extra ref from the write/commit path to handle handoff
256 * between write and commit lists. */
257 if (test_bit(PG_INODE_REF, &prev->wb_head->wb_flags)) {
258 inode = page_file_mapping(req->wb_page)->host;
259 set_bit(PG_INODE_REF, &req->wb_flags);
260 kref_get(&req->wb_kref);
261 atomic_long_inc(&NFS_I(inode)->nrequests);
262 }
263 }
264}
265
266/*
267 * nfs_page_group_destroy - sync the destruction of page groups
268 * @req - request that no longer needs the page group
269 *
270 * releases the page group reference from each member once all
271 * members have called this function.
272 */
273static void
274nfs_page_group_destroy(struct kref *kref)
275{
276 struct nfs_page *req = container_of(kref, struct nfs_page, wb_kref);
277 struct nfs_page *head = req->wb_head;
278 struct nfs_page *tmp, *next;
279
280 if (!nfs_page_group_sync_on_bit(req, PG_TEARDOWN))
281 goto out;
282
283 tmp = req;
284 do {
285 next = tmp->wb_this_page;
286 /* unlink and free */
287 tmp->wb_this_page = tmp;
288 tmp->wb_head = tmp;
289 nfs_free_request(tmp);
290 tmp = next;
291 } while (tmp != req);
292out:
293 /* subrequests must release the ref on the head request */
294 if (head != req)
295 nfs_release_request(head);
296}
297
298/**
299 * nfs_create_request - Create an NFS read/write request.
300 * @ctx: open context to use
301 * @page: page to write
302 * @last: last nfs request created for this page group or NULL if head
303 * @offset: starting offset within the page for the write
304 * @count: number of bytes to read/write
305 *
306 * The page must be locked by the caller. This makes sure we never
307 * create two different requests for the same page.
308 * User should ensure it is safe to sleep in this function.
309 */
310struct nfs_page *
311nfs_create_request(struct nfs_open_context *ctx, struct page *page,
312 struct nfs_page *last, unsigned int offset,
313 unsigned int count)
314{
315 struct nfs_page *req;
316 struct nfs_lock_context *l_ctx;
317
318 if (test_bit(NFS_CONTEXT_BAD, &ctx->flags))
319 return ERR_PTR(-EBADF);
320 /* try to allocate the request struct */
321 req = nfs_page_alloc();
322 if (req == NULL)
323 return ERR_PTR(-ENOMEM);
324
325 /* get lock context early so we can deal with alloc failures */
326 l_ctx = nfs_get_lock_context(ctx);
327 if (IS_ERR(l_ctx)) {
328 nfs_page_free(req);
329 return ERR_CAST(l_ctx);
330 }
331 req->wb_lock_context = l_ctx;
332 atomic_inc(&l_ctx->io_count);
333
334 /* Initialize the request struct. Initially, we assume a
335 * long write-back delay. This will be adjusted in
336 * update_nfs_request below if the region is not locked. */
337 req->wb_page = page;
338 if (page) {
339 req->wb_index = page_index(page);
340 get_page(page);
341 }
342 req->wb_offset = offset;
343 req->wb_pgbase = offset;
344 req->wb_bytes = count;
345 req->wb_context = get_nfs_open_context(ctx);
346 kref_init(&req->wb_kref);
347 nfs_page_group_init(req, last);
348 return req;
349}
350
351/**
352 * nfs_unlock_request - Unlock request and wake up sleepers.
353 * @req:
354 */
355void nfs_unlock_request(struct nfs_page *req)
356{
357 if (!NFS_WBACK_BUSY(req)) {
358 printk(KERN_ERR "NFS: Invalid unlock attempted\n");
359 BUG();
360 }
361 smp_mb__before_atomic();
362 clear_bit(PG_BUSY, &req->wb_flags);
363 smp_mb__after_atomic();
364 if (!test_bit(PG_CONTENDED2, &req->wb_flags))
365 return;
366 wake_up_bit(&req->wb_flags, PG_BUSY);
367}
368
369/**
370 * nfs_unlock_and_release_request - Unlock request and release the nfs_page
371 * @req:
372 */
373void nfs_unlock_and_release_request(struct nfs_page *req)
374{
375 nfs_unlock_request(req);
376 nfs_release_request(req);
377}
378
379/*
380 * nfs_clear_request - Free up all resources allocated to the request
381 * @req:
382 *
383 * Release page and open context resources associated with a read/write
384 * request after it has completed.
385 */
386static void nfs_clear_request(struct nfs_page *req)
387{
388 struct page *page = req->wb_page;
389 struct nfs_open_context *ctx = req->wb_context;
390 struct nfs_lock_context *l_ctx = req->wb_lock_context;
391
392 if (page != NULL) {
393 put_page(page);
394 req->wb_page = NULL;
395 }
396 if (l_ctx != NULL) {
397 if (atomic_dec_and_test(&l_ctx->io_count)) {
398 wake_up_var(&l_ctx->io_count);
399 if (test_bit(NFS_CONTEXT_UNLOCK, &ctx->flags))
400 rpc_wake_up(&NFS_SERVER(d_inode(ctx->dentry))->uoc_rpcwaitq);
401 }
402 nfs_put_lock_context(l_ctx);
403 req->wb_lock_context = NULL;
404 }
405 if (ctx != NULL) {
406 put_nfs_open_context(ctx);
407 req->wb_context = NULL;
408 }
409}
410
411/**
412 * nfs_release_request - Release the count on an NFS read/write request
413 * @req: request to release
414 *
415 * Note: Should never be called with the spinlock held!
416 */
417void nfs_free_request(struct nfs_page *req)
418{
419 WARN_ON_ONCE(req->wb_this_page != req);
420
421 /* extra debug: make sure no sync bits are still set */
422 WARN_ON_ONCE(test_bit(PG_TEARDOWN, &req->wb_flags));
423 WARN_ON_ONCE(test_bit(PG_UNLOCKPAGE, &req->wb_flags));
424 WARN_ON_ONCE(test_bit(PG_UPTODATE, &req->wb_flags));
425 WARN_ON_ONCE(test_bit(PG_WB_END, &req->wb_flags));
426 WARN_ON_ONCE(test_bit(PG_REMOVE, &req->wb_flags));
427
428 /* Release struct file and open context */
429 nfs_clear_request(req);
430 nfs_page_free(req);
431}
432
433void nfs_release_request(struct nfs_page *req)
434{
435 kref_put(&req->wb_kref, nfs_page_group_destroy);
436}
437EXPORT_SYMBOL_GPL(nfs_release_request);
438
439/**
440 * nfs_wait_on_request - Wait for a request to complete.
441 * @req: request to wait upon.
442 *
443 * Interruptible by fatal signals only.
444 * The user is responsible for holding a count on the request.
445 */
446int
447nfs_wait_on_request(struct nfs_page *req)
448{
449 if (!test_bit(PG_BUSY, &req->wb_flags))
450 return 0;
451 set_bit(PG_CONTENDED2, &req->wb_flags);
452 smp_mb__after_atomic();
453 return wait_on_bit_io(&req->wb_flags, PG_BUSY,
454 TASK_UNINTERRUPTIBLE);
455}
456EXPORT_SYMBOL_GPL(nfs_wait_on_request);
457
458/*
459 * nfs_generic_pg_test - determine if requests can be coalesced
460 * @desc: pointer to descriptor
461 * @prev: previous request in desc, or NULL
462 * @req: this request
463 *
464 * Returns zero if @req can be coalesced into @desc, otherwise it returns
465 * the size of the request.
466 */
467size_t nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
468 struct nfs_page *prev, struct nfs_page *req)
469{
470 struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
471
472
473 if (mirror->pg_count > mirror->pg_bsize) {
474 /* should never happen */
475 WARN_ON_ONCE(1);
476 return 0;
477 }
478
479 /*
480 * Limit the request size so that we can still allocate a page array
481 * for it without upsetting the slab allocator.
482 */
483 if (((mirror->pg_count + req->wb_bytes) >> PAGE_SHIFT) *
484 sizeof(struct page *) > PAGE_SIZE)
485 return 0;
486
487 return min(mirror->pg_bsize - mirror->pg_count, (size_t)req->wb_bytes);
488}
489EXPORT_SYMBOL_GPL(nfs_generic_pg_test);
490
491struct nfs_pgio_header *nfs_pgio_header_alloc(const struct nfs_rw_ops *ops)
492{
493 struct nfs_pgio_header *hdr = ops->rw_alloc_header();
494
495 if (hdr) {
496 INIT_LIST_HEAD(&hdr->pages);
497 spin_lock_init(&hdr->lock);
498 hdr->rw_ops = ops;
499 }
500 return hdr;
501}
502EXPORT_SYMBOL_GPL(nfs_pgio_header_alloc);
503
504/**
505 * nfs_pgio_data_destroy - make @hdr suitable for reuse
506 *
507 * Frees memory and releases refs from nfs_generic_pgio, so that it may
508 * be called again.
509 *
510 * @hdr: A header that has had nfs_generic_pgio called
511 */
512static void nfs_pgio_data_destroy(struct nfs_pgio_header *hdr)
513{
514 if (hdr->args.context)
515 put_nfs_open_context(hdr->args.context);
516 if (hdr->page_array.pagevec != hdr->page_array.page_array)
517 kfree(hdr->page_array.pagevec);
518}
519
520/*
521 * nfs_pgio_header_free - Free a read or write header
522 * @hdr: The header to free
523 */
524void nfs_pgio_header_free(struct nfs_pgio_header *hdr)
525{
526 nfs_pgio_data_destroy(hdr);
527 hdr->rw_ops->rw_free_header(hdr);
528}
529EXPORT_SYMBOL_GPL(nfs_pgio_header_free);
530
531/**
532 * nfs_pgio_rpcsetup - Set up arguments for a pageio call
533 * @hdr: The pageio hdr
534 * @count: Number of bytes to read
535 * @offset: Initial offset
536 * @how: How to commit data (writes only)
537 * @cinfo: Commit information for the call (writes only)
538 */
539static void nfs_pgio_rpcsetup(struct nfs_pgio_header *hdr,
540 unsigned int count,
541 int how, struct nfs_commit_info *cinfo)
542{
543 struct nfs_page *req = hdr->req;
544
545 /* Set up the RPC argument and reply structs
546 * NB: take care not to mess about with hdr->commit et al. */
547
548 hdr->args.fh = NFS_FH(hdr->inode);
549 hdr->args.offset = req_offset(req);
550 /* pnfs_set_layoutcommit needs this */
551 hdr->mds_offset = hdr->args.offset;
552 hdr->args.pgbase = req->wb_pgbase;
553 hdr->args.pages = hdr->page_array.pagevec;
554 hdr->args.count = count;
555 hdr->args.context = get_nfs_open_context(req->wb_context);
556 hdr->args.lock_context = req->wb_lock_context;
557 hdr->args.stable = NFS_UNSTABLE;
558 switch (how & (FLUSH_STABLE | FLUSH_COND_STABLE)) {
559 case 0:
560 break;
561 case FLUSH_COND_STABLE:
562 if (nfs_reqs_to_commit(cinfo))
563 break;
564 default:
565 hdr->args.stable = NFS_FILE_SYNC;
566 }
567
568 hdr->res.fattr = &hdr->fattr;
569 hdr->res.count = count;
570 hdr->res.eof = 0;
571 hdr->res.verf = &hdr->verf;
572 nfs_fattr_init(&hdr->fattr);
573}
574
575/**
576 * nfs_pgio_prepare - Prepare pageio hdr to go over the wire
577 * @task: The current task
578 * @calldata: pageio header to prepare
579 */
580static void nfs_pgio_prepare(struct rpc_task *task, void *calldata)
581{
582 struct nfs_pgio_header *hdr = calldata;
583 int err;
584 err = NFS_PROTO(hdr->inode)->pgio_rpc_prepare(task, hdr);
585 if (err)
586 rpc_exit(task, err);
587}
588
589int nfs_initiate_pgio(struct rpc_clnt *clnt, struct nfs_pgio_header *hdr,
590 struct rpc_cred *cred, const struct nfs_rpc_ops *rpc_ops,
591 const struct rpc_call_ops *call_ops, int how, int flags)
592{
593 struct rpc_task *task;
594 struct rpc_message msg = {
595 .rpc_argp = &hdr->args,
596 .rpc_resp = &hdr->res,
597 .rpc_cred = cred,
598 };
599 struct rpc_task_setup task_setup_data = {
600 .rpc_client = clnt,
601 .task = &hdr->task,
602 .rpc_message = &msg,
603 .callback_ops = call_ops,
604 .callback_data = hdr,
605 .workqueue = nfsiod_workqueue,
606 .flags = RPC_TASK_ASYNC | flags,
607 };
608 int ret = 0;
609
610 hdr->rw_ops->rw_initiate(hdr, &msg, rpc_ops, &task_setup_data, how);
611
612 dprintk("NFS: initiated pgio call "
613 "(req %s/%llu, %u bytes @ offset %llu)\n",
614 hdr->inode->i_sb->s_id,
615 (unsigned long long)NFS_FILEID(hdr->inode),
616 hdr->args.count,
617 (unsigned long long)hdr->args.offset);
618
619 task = rpc_run_task(&task_setup_data);
620 if (IS_ERR(task)) {
621 ret = PTR_ERR(task);
622 goto out;
623 }
624 if (how & FLUSH_SYNC) {
625 ret = rpc_wait_for_completion_task(task);
626 if (ret == 0)
627 ret = task->tk_status;
628 }
629 rpc_put_task(task);
630out:
631 return ret;
632}
633EXPORT_SYMBOL_GPL(nfs_initiate_pgio);
634
635/**
636 * nfs_pgio_error - Clean up from a pageio error
637 * @desc: IO descriptor
638 * @hdr: pageio header
639 */
640static void nfs_pgio_error(struct nfs_pgio_header *hdr)
641{
642 set_bit(NFS_IOHDR_REDO, &hdr->flags);
643 hdr->completion_ops->completion(hdr);
644}
645
646/**
647 * nfs_pgio_release - Release pageio data
648 * @calldata: The pageio header to release
649 */
650static void nfs_pgio_release(void *calldata)
651{
652 struct nfs_pgio_header *hdr = calldata;
653 hdr->completion_ops->completion(hdr);
654}
655
656static void nfs_pageio_mirror_init(struct nfs_pgio_mirror *mirror,
657 unsigned int bsize)
658{
659 INIT_LIST_HEAD(&mirror->pg_list);
660 mirror->pg_bytes_written = 0;
661 mirror->pg_count = 0;
662 mirror->pg_bsize = bsize;
663 mirror->pg_base = 0;
664 mirror->pg_recoalesce = 0;
665}
666
667/**
668 * nfs_pageio_init - initialise a page io descriptor
669 * @desc: pointer to descriptor
670 * @inode: pointer to inode
671 * @pg_ops: pointer to pageio operations
672 * @compl_ops: pointer to pageio completion operations
673 * @rw_ops: pointer to nfs read/write operations
674 * @bsize: io block size
675 * @io_flags: extra parameters for the io function
676 */
677void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
678 struct inode *inode,
679 const struct nfs_pageio_ops *pg_ops,
680 const struct nfs_pgio_completion_ops *compl_ops,
681 const struct nfs_rw_ops *rw_ops,
682 size_t bsize,
683 int io_flags)
684{
685 desc->pg_moreio = 0;
686 desc->pg_inode = inode;
687 desc->pg_ops = pg_ops;
688 desc->pg_completion_ops = compl_ops;
689 desc->pg_rw_ops = rw_ops;
690 desc->pg_ioflags = io_flags;
691 desc->pg_error = 0;
692 desc->pg_lseg = NULL;
693 desc->pg_io_completion = NULL;
694 desc->pg_dreq = NULL;
695 desc->pg_bsize = bsize;
696
697 desc->pg_mirror_count = 1;
698 desc->pg_mirror_idx = 0;
699
700 desc->pg_mirrors_dynamic = NULL;
701 desc->pg_mirrors = desc->pg_mirrors_static;
702 nfs_pageio_mirror_init(&desc->pg_mirrors[0], bsize);
703}
704
705/**
706 * nfs_pgio_result - Basic pageio error handling
707 * @task: The task that ran
708 * @calldata: Pageio header to check
709 */
710static void nfs_pgio_result(struct rpc_task *task, void *calldata)
711{
712 struct nfs_pgio_header *hdr = calldata;
713 struct inode *inode = hdr->inode;
714
715 dprintk("NFS: %s: %5u, (status %d)\n", __func__,
716 task->tk_pid, task->tk_status);
717
718 if (hdr->rw_ops->rw_done(task, hdr, inode) != 0)
719 return;
720 if (task->tk_status < 0)
721 nfs_set_pgio_error(hdr, task->tk_status, hdr->args.offset);
722 else
723 hdr->rw_ops->rw_result(task, hdr);
724}
725
726/*
727 * Create an RPC task for the given read or write request and kick it.
728 * The page must have been locked by the caller.
729 *
730 * It may happen that the page we're passed is not marked dirty.
731 * This is the case if nfs_updatepage detects a conflicting request
732 * that has been written but not committed.
733 */
734int nfs_generic_pgio(struct nfs_pageio_descriptor *desc,
735 struct nfs_pgio_header *hdr)
736{
737 struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
738
739 struct nfs_page *req;
740 struct page **pages,
741 *last_page;
742 struct list_head *head = &mirror->pg_list;
743 struct nfs_commit_info cinfo;
744 struct nfs_page_array *pg_array = &hdr->page_array;
745 unsigned int pagecount, pageused;
746 gfp_t gfp_flags = GFP_KERNEL;
747
748 pagecount = nfs_page_array_len(mirror->pg_base, mirror->pg_count);
749 pg_array->npages = pagecount;
750
751 if (pagecount <= ARRAY_SIZE(pg_array->page_array))
752 pg_array->pagevec = pg_array->page_array;
753 else {
754 if (hdr->rw_mode == FMODE_WRITE)
755 gfp_flags = GFP_NOIO;
756 pg_array->pagevec = kcalloc(pagecount, sizeof(struct page *), gfp_flags);
757 if (!pg_array->pagevec) {
758 pg_array->npages = 0;
759 nfs_pgio_error(hdr);
760 desc->pg_error = -ENOMEM;
761 return desc->pg_error;
762 }
763 }
764
765 nfs_init_cinfo(&cinfo, desc->pg_inode, desc->pg_dreq);
766 pages = hdr->page_array.pagevec;
767 last_page = NULL;
768 pageused = 0;
769 while (!list_empty(head)) {
770 req = nfs_list_entry(head->next);
771 nfs_list_remove_request(req);
772 nfs_list_add_request(req, &hdr->pages);
773
774 if (!last_page || last_page != req->wb_page) {
775 pageused++;
776 if (pageused > pagecount)
777 break;
778 *pages++ = last_page = req->wb_page;
779 }
780 }
781 if (WARN_ON_ONCE(pageused != pagecount)) {
782 nfs_pgio_error(hdr);
783 desc->pg_error = -EINVAL;
784 return desc->pg_error;
785 }
786
787 if ((desc->pg_ioflags & FLUSH_COND_STABLE) &&
788 (desc->pg_moreio || nfs_reqs_to_commit(&cinfo)))
789 desc->pg_ioflags &= ~FLUSH_COND_STABLE;
790
791 /* Set up the argument struct */
792 nfs_pgio_rpcsetup(hdr, mirror->pg_count, desc->pg_ioflags, &cinfo);
793 desc->pg_rpc_callops = &nfs_pgio_common_ops;
794 return 0;
795}
796EXPORT_SYMBOL_GPL(nfs_generic_pgio);
797
798static int nfs_generic_pg_pgios(struct nfs_pageio_descriptor *desc)
799{
800 struct nfs_pgio_header *hdr;
801 int ret;
802
803 hdr = nfs_pgio_header_alloc(desc->pg_rw_ops);
804 if (!hdr) {
805 desc->pg_error = -ENOMEM;
806 return desc->pg_error;
807 }
808 nfs_pgheader_init(desc, hdr, nfs_pgio_header_free);
809 ret = nfs_generic_pgio(desc, hdr);
810 if (ret == 0)
811 ret = nfs_initiate_pgio(NFS_CLIENT(hdr->inode),
812 hdr,
813 hdr->cred,
814 NFS_PROTO(hdr->inode),
815 desc->pg_rpc_callops,
816 desc->pg_ioflags, 0);
817 return ret;
818}
819
820static struct nfs_pgio_mirror *
821nfs_pageio_alloc_mirrors(struct nfs_pageio_descriptor *desc,
822 unsigned int mirror_count)
823{
824 struct nfs_pgio_mirror *ret;
825 unsigned int i;
826
827 kfree(desc->pg_mirrors_dynamic);
828 desc->pg_mirrors_dynamic = NULL;
829 if (mirror_count == 1)
830 return desc->pg_mirrors_static;
831 ret = kmalloc_array(mirror_count, sizeof(*ret), GFP_NOFS);
832 if (ret != NULL) {
833 for (i = 0; i < mirror_count; i++)
834 nfs_pageio_mirror_init(&ret[i], desc->pg_bsize);
835 desc->pg_mirrors_dynamic = ret;
836 }
837 return ret;
838}
839
840/*
841 * nfs_pageio_setup_mirroring - determine if mirroring is to be used
842 * by calling the pg_get_mirror_count op
843 */
844static void nfs_pageio_setup_mirroring(struct nfs_pageio_descriptor *pgio,
845 struct nfs_page *req)
846{
847 unsigned int mirror_count = 1;
848
849 if (pgio->pg_ops->pg_get_mirror_count)
850 mirror_count = pgio->pg_ops->pg_get_mirror_count(pgio, req);
851 if (mirror_count == pgio->pg_mirror_count || pgio->pg_error < 0)
852 return;
853
854 if (!mirror_count || mirror_count > NFS_PAGEIO_DESCRIPTOR_MIRROR_MAX) {
855 pgio->pg_error = -EINVAL;
856 return;
857 }
858
859 pgio->pg_mirrors = nfs_pageio_alloc_mirrors(pgio, mirror_count);
860 if (pgio->pg_mirrors == NULL) {
861 pgio->pg_error = -ENOMEM;
862 pgio->pg_mirrors = pgio->pg_mirrors_static;
863 mirror_count = 1;
864 }
865 pgio->pg_mirror_count = mirror_count;
866}
867
868/*
869 * nfs_pageio_stop_mirroring - stop using mirroring (set mirror count to 1)
870 */
871void nfs_pageio_stop_mirroring(struct nfs_pageio_descriptor *pgio)
872{
873 pgio->pg_mirror_count = 1;
874 pgio->pg_mirror_idx = 0;
875}
876
877static void nfs_pageio_cleanup_mirroring(struct nfs_pageio_descriptor *pgio)
878{
879 pgio->pg_mirror_count = 1;
880 pgio->pg_mirror_idx = 0;
881 pgio->pg_mirrors = pgio->pg_mirrors_static;
882 kfree(pgio->pg_mirrors_dynamic);
883 pgio->pg_mirrors_dynamic = NULL;
884}
885
886static bool nfs_match_lock_context(const struct nfs_lock_context *l1,
887 const struct nfs_lock_context *l2)
888{
889 return l1->lockowner == l2->lockowner;
890}
891
892/**
893 * nfs_can_coalesce_requests - test two requests for compatibility
894 * @prev: pointer to nfs_page
895 * @req: pointer to nfs_page
896 *
897 * The nfs_page structures 'prev' and 'req' are compared to ensure that the
898 * page data area they describe is contiguous, and that their RPC
899 * credentials, NFSv4 open state, and lockowners are the same.
900 *
901 * Return 'true' if this is the case, else return 'false'.
902 */
903static bool nfs_can_coalesce_requests(struct nfs_page *prev,
904 struct nfs_page *req,
905 struct nfs_pageio_descriptor *pgio)
906{
907 size_t size;
908 struct file_lock_context *flctx;
909
910 if (prev) {
911 if (!nfs_match_open_context(req->wb_context, prev->wb_context))
912 return false;
913 flctx = d_inode(req->wb_context->dentry)->i_flctx;
914 if (flctx != NULL &&
915 !(list_empty_careful(&flctx->flc_posix) &&
916 list_empty_careful(&flctx->flc_flock)) &&
917 !nfs_match_lock_context(req->wb_lock_context,
918 prev->wb_lock_context))
919 return false;
920 if (req_offset(req) != req_offset(prev) + prev->wb_bytes)
921 return false;
922 if (req->wb_page == prev->wb_page) {
923 if (req->wb_pgbase != prev->wb_pgbase + prev->wb_bytes)
924 return false;
925 } else {
926 if (req->wb_pgbase != 0 ||
927 prev->wb_pgbase + prev->wb_bytes != PAGE_SIZE)
928 return false;
929 }
930 }
931 size = pgio->pg_ops->pg_test(pgio, prev, req);
932 WARN_ON_ONCE(size > req->wb_bytes);
933 if (size && size < req->wb_bytes)
934 req->wb_bytes = size;
935 return size > 0;
936}
937
938/**
939 * nfs_pageio_do_add_request - Attempt to coalesce a request into a page list.
940 * @desc: destination io descriptor
941 * @req: request
942 *
943 * Returns true if the request 'req' was successfully coalesced into the
944 * existing list of pages 'desc'.
945 */
946static int nfs_pageio_do_add_request(struct nfs_pageio_descriptor *desc,
947 struct nfs_page *req)
948{
949 struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
950
951 struct nfs_page *prev = NULL;
952
953 if (mirror->pg_count != 0) {
954 prev = nfs_list_entry(mirror->pg_list.prev);
955 } else {
956 if (desc->pg_ops->pg_init)
957 desc->pg_ops->pg_init(desc, req);
958 if (desc->pg_error < 0)
959 return 0;
960 mirror->pg_base = req->wb_pgbase;
961 }
962 if (!nfs_can_coalesce_requests(prev, req, desc))
963 return 0;
964 nfs_list_remove_request(req);
965 nfs_list_add_request(req, &mirror->pg_list);
966 mirror->pg_count += req->wb_bytes;
967 return 1;
968}
969
970/*
971 * Helper for nfs_pageio_add_request and nfs_pageio_complete
972 */
973static void nfs_pageio_doio(struct nfs_pageio_descriptor *desc)
974{
975 struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
976
977
978 if (!list_empty(&mirror->pg_list)) {
979 int error = desc->pg_ops->pg_doio(desc);
980 if (error < 0)
981 desc->pg_error = error;
982 else
983 mirror->pg_bytes_written += mirror->pg_count;
984 }
985 if (list_empty(&mirror->pg_list)) {
986 mirror->pg_count = 0;
987 mirror->pg_base = 0;
988 }
989}
990
991/**
992 * nfs_pageio_add_request - Attempt to coalesce a request into a page list.
993 * @desc: destination io descriptor
994 * @req: request
995 *
996 * This may split a request into subrequests which are all part of the
997 * same page group.
998 *
999 * Returns true if the request 'req' was successfully coalesced into the
1000 * existing list of pages 'desc'.
1001 */
1002static int __nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
1003 struct nfs_page *req)
1004{
1005 struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
1006
1007 struct nfs_page *subreq;
1008 unsigned int bytes_left = 0;
1009 unsigned int offset, pgbase;
1010
1011 nfs_page_group_lock(req);
1012
1013 subreq = req;
1014 bytes_left = subreq->wb_bytes;
1015 offset = subreq->wb_offset;
1016 pgbase = subreq->wb_pgbase;
1017
1018 do {
1019 if (!nfs_pageio_do_add_request(desc, subreq)) {
1020 /* make sure pg_test call(s) did nothing */
1021 WARN_ON_ONCE(subreq->wb_bytes != bytes_left);
1022 WARN_ON_ONCE(subreq->wb_offset != offset);
1023 WARN_ON_ONCE(subreq->wb_pgbase != pgbase);
1024
1025 nfs_page_group_unlock(req);
1026 desc->pg_moreio = 1;
1027 nfs_pageio_doio(desc);
1028 if (desc->pg_error < 0)
1029 return 0;
1030 if (mirror->pg_recoalesce)
1031 return 0;
1032 /* retry add_request for this subreq */
1033 nfs_page_group_lock(req);
1034 continue;
1035 }
1036
1037 /* check for buggy pg_test call(s) */
1038 WARN_ON_ONCE(subreq->wb_bytes + subreq->wb_pgbase > PAGE_SIZE);
1039 WARN_ON_ONCE(subreq->wb_bytes > bytes_left);
1040 WARN_ON_ONCE(subreq->wb_bytes == 0);
1041
1042 bytes_left -= subreq->wb_bytes;
1043 offset += subreq->wb_bytes;
1044 pgbase += subreq->wb_bytes;
1045
1046 if (bytes_left) {
1047 subreq = nfs_create_request(req->wb_context,
1048 req->wb_page,
1049 subreq, pgbase, bytes_left);
1050 if (IS_ERR(subreq))
1051 goto err_ptr;
1052 nfs_lock_request(subreq);
1053 subreq->wb_offset = offset;
1054 subreq->wb_index = req->wb_index;
1055 }
1056 } while (bytes_left > 0);
1057
1058 nfs_page_group_unlock(req);
1059 return 1;
1060err_ptr:
1061 desc->pg_error = PTR_ERR(subreq);
1062 nfs_page_group_unlock(req);
1063 return 0;
1064}
1065
1066static int nfs_do_recoalesce(struct nfs_pageio_descriptor *desc)
1067{
1068 struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
1069 LIST_HEAD(head);
1070
1071 do {
1072 list_splice_init(&mirror->pg_list, &head);
1073 mirror->pg_bytes_written -= mirror->pg_count;
1074 mirror->pg_count = 0;
1075 mirror->pg_base = 0;
1076 mirror->pg_recoalesce = 0;
1077
1078 while (!list_empty(&head)) {
1079 struct nfs_page *req;
1080
1081 req = list_first_entry(&head, struct nfs_page, wb_list);
1082 nfs_list_remove_request(req);
1083 if (__nfs_pageio_add_request(desc, req))
1084 continue;
1085 if (desc->pg_error < 0) {
1086 list_splice_tail(&head, &mirror->pg_list);
1087 mirror->pg_recoalesce = 1;
1088 return 0;
1089 }
1090 break;
1091 }
1092 } while (mirror->pg_recoalesce);
1093 return 1;
1094}
1095
1096static int nfs_pageio_add_request_mirror(struct nfs_pageio_descriptor *desc,
1097 struct nfs_page *req)
1098{
1099 int ret;
1100
1101 do {
1102 ret = __nfs_pageio_add_request(desc, req);
1103 if (ret)
1104 break;
1105 if (desc->pg_error < 0)
1106 break;
1107 ret = nfs_do_recoalesce(desc);
1108 } while (ret);
1109
1110 return ret;
1111}
1112
1113int nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
1114 struct nfs_page *req)
1115{
1116 u32 midx;
1117 unsigned int pgbase, offset, bytes;
1118 struct nfs_page *dupreq, *lastreq;
1119
1120 pgbase = req->wb_pgbase;
1121 offset = req->wb_offset;
1122 bytes = req->wb_bytes;
1123
1124 nfs_pageio_setup_mirroring(desc, req);
1125 if (desc->pg_error < 0)
1126 goto out_failed;
1127
1128 for (midx = 0; midx < desc->pg_mirror_count; midx++) {
1129 if (midx) {
1130 nfs_page_group_lock(req);
1131
1132 /* find the last request */
1133 for (lastreq = req->wb_head;
1134 lastreq->wb_this_page != req->wb_head;
1135 lastreq = lastreq->wb_this_page)
1136 ;
1137
1138 dupreq = nfs_create_request(req->wb_context,
1139 req->wb_page, lastreq, pgbase, bytes);
1140
1141 if (IS_ERR(dupreq)) {
1142 nfs_page_group_unlock(req);
1143 desc->pg_error = PTR_ERR(dupreq);
1144 goto out_failed;
1145 }
1146
1147 nfs_lock_request(dupreq);
1148 nfs_page_group_unlock(req);
1149 dupreq->wb_offset = offset;
1150 dupreq->wb_index = req->wb_index;
1151 } else
1152 dupreq = req;
1153
1154 if (nfs_pgio_has_mirroring(desc))
1155 desc->pg_mirror_idx = midx;
1156 if (!nfs_pageio_add_request_mirror(desc, dupreq))
1157 goto out_failed;
1158 }
1159
1160 return 1;
1161
1162out_failed:
1163 /*
1164 * We might have failed before sending any reqs over wire.
1165 * Clean up rest of the reqs in mirror pg_list.
1166 */
1167 if (desc->pg_error) {
1168 struct nfs_pgio_mirror *mirror;
1169 void (*func)(struct list_head *);
1170
1171 /* remember fatal errors */
1172 if (nfs_error_is_fatal(desc->pg_error))
1173 nfs_context_set_write_error(req->wb_context,
1174 desc->pg_error);
1175
1176 func = desc->pg_completion_ops->error_cleanup;
1177 for (midx = 0; midx < desc->pg_mirror_count; midx++) {
1178 mirror = &desc->pg_mirrors[midx];
1179 func(&mirror->pg_list);
1180 }
1181 }
1182 return 0;
1183}
1184
1185/*
1186 * nfs_pageio_complete_mirror - Complete I/O on the current mirror of an
1187 * nfs_pageio_descriptor
1188 * @desc: pointer to io descriptor
1189 * @mirror_idx: pointer to mirror index
1190 */
1191static void nfs_pageio_complete_mirror(struct nfs_pageio_descriptor *desc,
1192 u32 mirror_idx)
1193{
1194 struct nfs_pgio_mirror *mirror = &desc->pg_mirrors[mirror_idx];
1195 u32 restore_idx = desc->pg_mirror_idx;
1196
1197 if (nfs_pgio_has_mirroring(desc))
1198 desc->pg_mirror_idx = mirror_idx;
1199 for (;;) {
1200 nfs_pageio_doio(desc);
1201 if (!mirror->pg_recoalesce)
1202 break;
1203 if (!nfs_do_recoalesce(desc))
1204 break;
1205 }
1206 desc->pg_mirror_idx = restore_idx;
1207}
1208
1209/*
1210 * nfs_pageio_resend - Transfer requests to new descriptor and resend
1211 * @hdr - the pgio header to move request from
1212 * @desc - the pageio descriptor to add requests to
1213 *
1214 * Try to move each request (nfs_page) from @hdr to @desc then attempt
1215 * to send them.
1216 *
1217 * Returns 0 on success and < 0 on error.
1218 */
1219int nfs_pageio_resend(struct nfs_pageio_descriptor *desc,
1220 struct nfs_pgio_header *hdr)
1221{
1222 LIST_HEAD(failed);
1223
1224 desc->pg_io_completion = hdr->io_completion;
1225 desc->pg_dreq = hdr->dreq;
1226 while (!list_empty(&hdr->pages)) {
1227 struct nfs_page *req = nfs_list_entry(hdr->pages.next);
1228
1229 nfs_list_remove_request(req);
1230 if (!nfs_pageio_add_request(desc, req))
1231 nfs_list_add_request(req, &failed);
1232 }
1233 nfs_pageio_complete(desc);
1234 if (!list_empty(&failed)) {
1235 list_move(&failed, &hdr->pages);
1236 return desc->pg_error < 0 ? desc->pg_error : -EIO;
1237 }
1238 return 0;
1239}
1240EXPORT_SYMBOL_GPL(nfs_pageio_resend);
1241
1242/**
1243 * nfs_pageio_complete - Complete I/O then cleanup an nfs_pageio_descriptor
1244 * @desc: pointer to io descriptor
1245 */
1246void nfs_pageio_complete(struct nfs_pageio_descriptor *desc)
1247{
1248 u32 midx;
1249
1250 for (midx = 0; midx < desc->pg_mirror_count; midx++)
1251 nfs_pageio_complete_mirror(desc, midx);
1252
1253 if (desc->pg_ops->pg_cleanup)
1254 desc->pg_ops->pg_cleanup(desc);
1255 nfs_pageio_cleanup_mirroring(desc);
1256}
1257
1258/**
1259 * nfs_pageio_cond_complete - Conditional I/O completion
1260 * @desc: pointer to io descriptor
1261 * @index: page index
1262 *
1263 * It is important to ensure that processes don't try to take locks
1264 * on non-contiguous ranges of pages as that might deadlock. This
1265 * function should be called before attempting to wait on a locked
1266 * nfs_page. It will complete the I/O if the page index 'index'
1267 * is not contiguous with the existing list of pages in 'desc'.
1268 */
1269void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *desc, pgoff_t index)
1270{
1271 struct nfs_pgio_mirror *mirror;
1272 struct nfs_page *prev;
1273 u32 midx;
1274
1275 for (midx = 0; midx < desc->pg_mirror_count; midx++) {
1276 mirror = &desc->pg_mirrors[midx];
1277 if (!list_empty(&mirror->pg_list)) {
1278 prev = nfs_list_entry(mirror->pg_list.prev);
1279 if (index != prev->wb_index + 1) {
1280 nfs_pageio_complete(desc);
1281 break;
1282 }
1283 }
1284 }
1285}
1286
1287int __init nfs_init_nfspagecache(void)
1288{
1289 nfs_page_cachep = kmem_cache_create("nfs_page",
1290 sizeof(struct nfs_page),
1291 0, SLAB_HWCACHE_ALIGN,
1292 NULL);
1293 if (nfs_page_cachep == NULL)
1294 return -ENOMEM;
1295
1296 return 0;
1297}
1298
1299void nfs_destroy_nfspagecache(void)
1300{
1301 kmem_cache_destroy(nfs_page_cachep);
1302}
1303
1304static const struct rpc_call_ops nfs_pgio_common_ops = {
1305 .rpc_call_prepare = nfs_pgio_prepare,
1306 .rpc_call_done = nfs_pgio_result,
1307 .rpc_release = nfs_pgio_release,
1308};
1309
1310const struct nfs_pageio_ops nfs_pgio_rw_ops = {
1311 .pg_test = nfs_generic_pg_test,
1312 .pg_doio = nfs_generic_pg_pgios,
1313};
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/fs/nfs/pagelist.c
4 *
5 * A set of helper functions for managing NFS read and write requests.
6 * The main purpose of these routines is to provide support for the
7 * coalescing of several requests into a single RPC call.
8 *
9 * Copyright 2000, 2001 (c) Trond Myklebust <trond.myklebust@fys.uio.no>
10 *
11 */
12
13#include <linux/slab.h>
14#include <linux/file.h>
15#include <linux/sched.h>
16#include <linux/sunrpc/clnt.h>
17#include <linux/nfs.h>
18#include <linux/nfs3.h>
19#include <linux/nfs4.h>
20#include <linux/nfs_fs.h>
21#include <linux/nfs_page.h>
22#include <linux/nfs_mount.h>
23#include <linux/export.h>
24
25#include "internal.h"
26#include "pnfs.h"
27#include "nfstrace.h"
28
29#define NFSDBG_FACILITY NFSDBG_PAGECACHE
30
31static struct kmem_cache *nfs_page_cachep;
32static const struct rpc_call_ops nfs_pgio_common_ops;
33
34static struct nfs_pgio_mirror *
35nfs_pgio_get_mirror(struct nfs_pageio_descriptor *desc, u32 idx)
36{
37 if (desc->pg_ops->pg_get_mirror)
38 return desc->pg_ops->pg_get_mirror(desc, idx);
39 return &desc->pg_mirrors[0];
40}
41
42struct nfs_pgio_mirror *
43nfs_pgio_current_mirror(struct nfs_pageio_descriptor *desc)
44{
45 return nfs_pgio_get_mirror(desc, desc->pg_mirror_idx);
46}
47EXPORT_SYMBOL_GPL(nfs_pgio_current_mirror);
48
49static u32
50nfs_pgio_set_current_mirror(struct nfs_pageio_descriptor *desc, u32 idx)
51{
52 if (desc->pg_ops->pg_set_mirror)
53 return desc->pg_ops->pg_set_mirror(desc, idx);
54 return desc->pg_mirror_idx;
55}
56
57void nfs_pgheader_init(struct nfs_pageio_descriptor *desc,
58 struct nfs_pgio_header *hdr,
59 void (*release)(struct nfs_pgio_header *hdr))
60{
61 struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
62
63
64 hdr->req = nfs_list_entry(mirror->pg_list.next);
65 hdr->inode = desc->pg_inode;
66 hdr->cred = nfs_req_openctx(hdr->req)->cred;
67 hdr->io_start = req_offset(hdr->req);
68 hdr->good_bytes = mirror->pg_count;
69 hdr->io_completion = desc->pg_io_completion;
70 hdr->dreq = desc->pg_dreq;
71 hdr->release = release;
72 hdr->completion_ops = desc->pg_completion_ops;
73 if (hdr->completion_ops->init_hdr)
74 hdr->completion_ops->init_hdr(hdr);
75
76 hdr->pgio_mirror_idx = desc->pg_mirror_idx;
77}
78EXPORT_SYMBOL_GPL(nfs_pgheader_init);
79
80void nfs_set_pgio_error(struct nfs_pgio_header *hdr, int error, loff_t pos)
81{
82 unsigned int new = pos - hdr->io_start;
83
84 trace_nfs_pgio_error(hdr, error, pos);
85 if (hdr->good_bytes > new) {
86 hdr->good_bytes = new;
87 clear_bit(NFS_IOHDR_EOF, &hdr->flags);
88 if (!test_and_set_bit(NFS_IOHDR_ERROR, &hdr->flags))
89 hdr->error = error;
90 }
91}
92
93static inline struct nfs_page *nfs_page_alloc(void)
94{
95 struct nfs_page *p =
96 kmem_cache_zalloc(nfs_page_cachep, nfs_io_gfp_mask());
97 if (p)
98 INIT_LIST_HEAD(&p->wb_list);
99 return p;
100}
101
102static inline void
103nfs_page_free(struct nfs_page *p)
104{
105 kmem_cache_free(nfs_page_cachep, p);
106}
107
108/**
109 * nfs_iocounter_wait - wait for i/o to complete
110 * @l_ctx: nfs_lock_context with io_counter to use
111 *
112 * returns -ERESTARTSYS if interrupted by a fatal signal.
113 * Otherwise returns 0 once the io_count hits 0.
114 */
115int
116nfs_iocounter_wait(struct nfs_lock_context *l_ctx)
117{
118 return wait_var_event_killable(&l_ctx->io_count,
119 !atomic_read(&l_ctx->io_count));
120}
121
122/**
123 * nfs_async_iocounter_wait - wait on a rpc_waitqueue for I/O
124 * to complete
125 * @task: the rpc_task that should wait
126 * @l_ctx: nfs_lock_context with io_counter to check
127 *
128 * Returns true if there is outstanding I/O to wait on and the
129 * task has been put to sleep.
130 */
131bool
132nfs_async_iocounter_wait(struct rpc_task *task, struct nfs_lock_context *l_ctx)
133{
134 struct inode *inode = d_inode(l_ctx->open_context->dentry);
135 bool ret = false;
136
137 if (atomic_read(&l_ctx->io_count) > 0) {
138 rpc_sleep_on(&NFS_SERVER(inode)->uoc_rpcwaitq, task, NULL);
139 ret = true;
140 }
141
142 if (atomic_read(&l_ctx->io_count) == 0) {
143 rpc_wake_up_queued_task(&NFS_SERVER(inode)->uoc_rpcwaitq, task);
144 ret = false;
145 }
146
147 return ret;
148}
149EXPORT_SYMBOL_GPL(nfs_async_iocounter_wait);
150
151/*
152 * nfs_page_lock_head_request - page lock the head of the page group
153 * @req: any member of the page group
154 */
155struct nfs_page *
156nfs_page_group_lock_head(struct nfs_page *req)
157{
158 struct nfs_page *head = req->wb_head;
159
160 while (!nfs_lock_request(head)) {
161 int ret = nfs_wait_on_request(head);
162 if (ret < 0)
163 return ERR_PTR(ret);
164 }
165 if (head != req)
166 kref_get(&head->wb_kref);
167 return head;
168}
169
170/*
171 * nfs_unroll_locks - unlock all newly locked reqs and wait on @req
172 * @head: head request of page group, must be holding head lock
173 * @req: request that couldn't lock and needs to wait on the req bit lock
174 *
175 * This is a helper function for nfs_lock_and_join_requests
176 * returns 0 on success, < 0 on error.
177 */
178static void
179nfs_unroll_locks(struct nfs_page *head, struct nfs_page *req)
180{
181 struct nfs_page *tmp;
182
183 /* relinquish all the locks successfully grabbed this run */
184 for (tmp = head->wb_this_page ; tmp != req; tmp = tmp->wb_this_page) {
185 if (!kref_read(&tmp->wb_kref))
186 continue;
187 nfs_unlock_and_release_request(tmp);
188 }
189}
190
191/*
192 * nfs_page_group_lock_subreq - try to lock a subrequest
193 * @head: head request of page group
194 * @subreq: request to lock
195 *
196 * This is a helper function for nfs_lock_and_join_requests which
197 * must be called with the head request and page group both locked.
198 * On error, it returns with the page group unlocked.
199 */
200static int
201nfs_page_group_lock_subreq(struct nfs_page *head, struct nfs_page *subreq)
202{
203 int ret;
204
205 if (!kref_get_unless_zero(&subreq->wb_kref))
206 return 0;
207 while (!nfs_lock_request(subreq)) {
208 nfs_page_group_unlock(head);
209 ret = nfs_wait_on_request(subreq);
210 if (!ret)
211 ret = nfs_page_group_lock(head);
212 if (ret < 0) {
213 nfs_unroll_locks(head, subreq);
214 nfs_release_request(subreq);
215 return ret;
216 }
217 }
218 return 0;
219}
220
221/*
222 * nfs_page_group_lock_subrequests - try to lock the subrequests
223 * @head: head request of page group
224 *
225 * This is a helper function for nfs_lock_and_join_requests which
226 * must be called with the head request locked.
227 */
228int nfs_page_group_lock_subrequests(struct nfs_page *head)
229{
230 struct nfs_page *subreq;
231 int ret;
232
233 ret = nfs_page_group_lock(head);
234 if (ret < 0)
235 return ret;
236 /* lock each request in the page group */
237 for (subreq = head->wb_this_page; subreq != head;
238 subreq = subreq->wb_this_page) {
239 ret = nfs_page_group_lock_subreq(head, subreq);
240 if (ret < 0)
241 return ret;
242 }
243 nfs_page_group_unlock(head);
244 return 0;
245}
246
247/*
248 * nfs_page_set_headlock - set the request PG_HEADLOCK
249 * @req: request that is to be locked
250 *
251 * this lock must be held when modifying req->wb_head
252 *
253 * return 0 on success, < 0 on error
254 */
255int
256nfs_page_set_headlock(struct nfs_page *req)
257{
258 if (!test_and_set_bit(PG_HEADLOCK, &req->wb_flags))
259 return 0;
260
261 set_bit(PG_CONTENDED1, &req->wb_flags);
262 smp_mb__after_atomic();
263 return wait_on_bit_lock(&req->wb_flags, PG_HEADLOCK,
264 TASK_UNINTERRUPTIBLE);
265}
266
267/*
268 * nfs_page_clear_headlock - clear the request PG_HEADLOCK
269 * @req: request that is to be locked
270 */
271void
272nfs_page_clear_headlock(struct nfs_page *req)
273{
274 clear_bit_unlock(PG_HEADLOCK, &req->wb_flags);
275 smp_mb__after_atomic();
276 if (!test_bit(PG_CONTENDED1, &req->wb_flags))
277 return;
278 wake_up_bit(&req->wb_flags, PG_HEADLOCK);
279}
280
281/*
282 * nfs_page_group_lock - lock the head of the page group
283 * @req: request in group that is to be locked
284 *
285 * this lock must be held when traversing or modifying the page
286 * group list
287 *
288 * return 0 on success, < 0 on error
289 */
290int
291nfs_page_group_lock(struct nfs_page *req)
292{
293 int ret;
294
295 ret = nfs_page_set_headlock(req);
296 if (ret || req->wb_head == req)
297 return ret;
298 return nfs_page_set_headlock(req->wb_head);
299}
300
301/*
302 * nfs_page_group_unlock - unlock the head of the page group
303 * @req: request in group that is to be unlocked
304 */
305void
306nfs_page_group_unlock(struct nfs_page *req)
307{
308 if (req != req->wb_head)
309 nfs_page_clear_headlock(req->wb_head);
310 nfs_page_clear_headlock(req);
311}
312
313/*
314 * nfs_page_group_sync_on_bit_locked
315 *
316 * must be called with page group lock held
317 */
318static bool
319nfs_page_group_sync_on_bit_locked(struct nfs_page *req, unsigned int bit)
320{
321 struct nfs_page *head = req->wb_head;
322 struct nfs_page *tmp;
323
324 WARN_ON_ONCE(!test_bit(PG_HEADLOCK, &head->wb_flags));
325 WARN_ON_ONCE(test_and_set_bit(bit, &req->wb_flags));
326
327 tmp = req->wb_this_page;
328 while (tmp != req) {
329 if (!test_bit(bit, &tmp->wb_flags))
330 return false;
331 tmp = tmp->wb_this_page;
332 }
333
334 /* true! reset all bits */
335 tmp = req;
336 do {
337 clear_bit(bit, &tmp->wb_flags);
338 tmp = tmp->wb_this_page;
339 } while (tmp != req);
340
341 return true;
342}
343
344/*
345 * nfs_page_group_sync_on_bit - set bit on current request, but only
346 * return true if the bit is set for all requests in page group
347 * @req - request in page group
348 * @bit - PG_* bit that is used to sync page group
349 */
350bool nfs_page_group_sync_on_bit(struct nfs_page *req, unsigned int bit)
351{
352 bool ret;
353
354 nfs_page_group_lock(req);
355 ret = nfs_page_group_sync_on_bit_locked(req, bit);
356 nfs_page_group_unlock(req);
357
358 return ret;
359}
360
361/*
362 * nfs_page_group_init - Initialize the page group linkage for @req
363 * @req - a new nfs request
364 * @prev - the previous request in page group, or NULL if @req is the first
365 * or only request in the group (the head).
366 */
367static inline void
368nfs_page_group_init(struct nfs_page *req, struct nfs_page *prev)
369{
370 struct inode *inode;
371 WARN_ON_ONCE(prev == req);
372
373 if (!prev) {
374 /* a head request */
375 req->wb_head = req;
376 req->wb_this_page = req;
377 } else {
378 /* a subrequest */
379 WARN_ON_ONCE(prev->wb_this_page != prev->wb_head);
380 WARN_ON_ONCE(!test_bit(PG_HEADLOCK, &prev->wb_head->wb_flags));
381 req->wb_head = prev->wb_head;
382 req->wb_this_page = prev->wb_this_page;
383 prev->wb_this_page = req;
384
385 /* All subrequests take a ref on the head request until
386 * nfs_page_group_destroy is called */
387 kref_get(&req->wb_head->wb_kref);
388
389 /* grab extra ref and bump the request count if head request
390 * has extra ref from the write/commit path to handle handoff
391 * between write and commit lists. */
392 if (test_bit(PG_INODE_REF, &prev->wb_head->wb_flags)) {
393 inode = page_file_mapping(req->wb_page)->host;
394 set_bit(PG_INODE_REF, &req->wb_flags);
395 kref_get(&req->wb_kref);
396 atomic_long_inc(&NFS_I(inode)->nrequests);
397 }
398 }
399}
400
401/*
402 * nfs_page_group_destroy - sync the destruction of page groups
403 * @req - request that no longer needs the page group
404 *
405 * releases the page group reference from each member once all
406 * members have called this function.
407 */
408static void
409nfs_page_group_destroy(struct kref *kref)
410{
411 struct nfs_page *req = container_of(kref, struct nfs_page, wb_kref);
412 struct nfs_page *head = req->wb_head;
413 struct nfs_page *tmp, *next;
414
415 if (!nfs_page_group_sync_on_bit(req, PG_TEARDOWN))
416 goto out;
417
418 tmp = req;
419 do {
420 next = tmp->wb_this_page;
421 /* unlink and free */
422 tmp->wb_this_page = tmp;
423 tmp->wb_head = tmp;
424 nfs_free_request(tmp);
425 tmp = next;
426 } while (tmp != req);
427out:
428 /* subrequests must release the ref on the head request */
429 if (head != req)
430 nfs_release_request(head);
431}
432
433static struct nfs_page *
434__nfs_create_request(struct nfs_lock_context *l_ctx, struct page *page,
435 unsigned int pgbase, unsigned int offset,
436 unsigned int count)
437{
438 struct nfs_page *req;
439 struct nfs_open_context *ctx = l_ctx->open_context;
440
441 if (test_bit(NFS_CONTEXT_BAD, &ctx->flags))
442 return ERR_PTR(-EBADF);
443 /* try to allocate the request struct */
444 req = nfs_page_alloc();
445 if (req == NULL)
446 return ERR_PTR(-ENOMEM);
447
448 req->wb_lock_context = l_ctx;
449 refcount_inc(&l_ctx->count);
450 atomic_inc(&l_ctx->io_count);
451
452 /* Initialize the request struct. Initially, we assume a
453 * long write-back delay. This will be adjusted in
454 * update_nfs_request below if the region is not locked. */
455 req->wb_page = page;
456 if (page) {
457 req->wb_index = page_index(page);
458 get_page(page);
459 }
460 req->wb_offset = offset;
461 req->wb_pgbase = pgbase;
462 req->wb_bytes = count;
463 kref_init(&req->wb_kref);
464 req->wb_nio = 0;
465 return req;
466}
467
468/**
469 * nfs_create_request - Create an NFS read/write request.
470 * @ctx: open context to use
471 * @page: page to write
472 * @offset: starting offset within the page for the write
473 * @count: number of bytes to read/write
474 *
475 * The page must be locked by the caller. This makes sure we never
476 * create two different requests for the same page.
477 * User should ensure it is safe to sleep in this function.
478 */
479struct nfs_page *
480nfs_create_request(struct nfs_open_context *ctx, struct page *page,
481 unsigned int offset, unsigned int count)
482{
483 struct nfs_lock_context *l_ctx = nfs_get_lock_context(ctx);
484 struct nfs_page *ret;
485
486 if (IS_ERR(l_ctx))
487 return ERR_CAST(l_ctx);
488 ret = __nfs_create_request(l_ctx, page, offset, offset, count);
489 if (!IS_ERR(ret))
490 nfs_page_group_init(ret, NULL);
491 nfs_put_lock_context(l_ctx);
492 return ret;
493}
494
495static struct nfs_page *
496nfs_create_subreq(struct nfs_page *req,
497 unsigned int pgbase,
498 unsigned int offset,
499 unsigned int count)
500{
501 struct nfs_page *last;
502 struct nfs_page *ret;
503
504 ret = __nfs_create_request(req->wb_lock_context, req->wb_page,
505 pgbase, offset, count);
506 if (!IS_ERR(ret)) {
507 /* find the last request */
508 for (last = req->wb_head;
509 last->wb_this_page != req->wb_head;
510 last = last->wb_this_page)
511 ;
512
513 nfs_lock_request(ret);
514 ret->wb_index = req->wb_index;
515 nfs_page_group_init(ret, last);
516 ret->wb_nio = req->wb_nio;
517 }
518 return ret;
519}
520
521/**
522 * nfs_unlock_request - Unlock request and wake up sleepers.
523 * @req: pointer to request
524 */
525void nfs_unlock_request(struct nfs_page *req)
526{
527 clear_bit_unlock(PG_BUSY, &req->wb_flags);
528 smp_mb__after_atomic();
529 if (!test_bit(PG_CONTENDED2, &req->wb_flags))
530 return;
531 wake_up_bit(&req->wb_flags, PG_BUSY);
532}
533
534/**
535 * nfs_unlock_and_release_request - Unlock request and release the nfs_page
536 * @req: pointer to request
537 */
538void nfs_unlock_and_release_request(struct nfs_page *req)
539{
540 nfs_unlock_request(req);
541 nfs_release_request(req);
542}
543
544/*
545 * nfs_clear_request - Free up all resources allocated to the request
546 * @req:
547 *
548 * Release page and open context resources associated with a read/write
549 * request after it has completed.
550 */
551static void nfs_clear_request(struct nfs_page *req)
552{
553 struct page *page = req->wb_page;
554 struct nfs_lock_context *l_ctx = req->wb_lock_context;
555 struct nfs_open_context *ctx;
556
557 if (page != NULL) {
558 put_page(page);
559 req->wb_page = NULL;
560 }
561 if (l_ctx != NULL) {
562 if (atomic_dec_and_test(&l_ctx->io_count)) {
563 wake_up_var(&l_ctx->io_count);
564 ctx = l_ctx->open_context;
565 if (test_bit(NFS_CONTEXT_UNLOCK, &ctx->flags))
566 rpc_wake_up(&NFS_SERVER(d_inode(ctx->dentry))->uoc_rpcwaitq);
567 }
568 nfs_put_lock_context(l_ctx);
569 req->wb_lock_context = NULL;
570 }
571}
572
573/**
574 * nfs_free_request - Release the count on an NFS read/write request
575 * @req: request to release
576 *
577 * Note: Should never be called with the spinlock held!
578 */
579void nfs_free_request(struct nfs_page *req)
580{
581 WARN_ON_ONCE(req->wb_this_page != req);
582
583 /* extra debug: make sure no sync bits are still set */
584 WARN_ON_ONCE(test_bit(PG_TEARDOWN, &req->wb_flags));
585 WARN_ON_ONCE(test_bit(PG_UNLOCKPAGE, &req->wb_flags));
586 WARN_ON_ONCE(test_bit(PG_UPTODATE, &req->wb_flags));
587 WARN_ON_ONCE(test_bit(PG_WB_END, &req->wb_flags));
588 WARN_ON_ONCE(test_bit(PG_REMOVE, &req->wb_flags));
589
590 /* Release struct file and open context */
591 nfs_clear_request(req);
592 nfs_page_free(req);
593}
594
595void nfs_release_request(struct nfs_page *req)
596{
597 kref_put(&req->wb_kref, nfs_page_group_destroy);
598}
599EXPORT_SYMBOL_GPL(nfs_release_request);
600
601/**
602 * nfs_wait_on_request - Wait for a request to complete.
603 * @req: request to wait upon.
604 *
605 * Interruptible by fatal signals only.
606 * The user is responsible for holding a count on the request.
607 */
608int
609nfs_wait_on_request(struct nfs_page *req)
610{
611 if (!test_bit(PG_BUSY, &req->wb_flags))
612 return 0;
613 set_bit(PG_CONTENDED2, &req->wb_flags);
614 smp_mb__after_atomic();
615 return wait_on_bit_io(&req->wb_flags, PG_BUSY,
616 TASK_UNINTERRUPTIBLE);
617}
618EXPORT_SYMBOL_GPL(nfs_wait_on_request);
619
620/*
621 * nfs_generic_pg_test - determine if requests can be coalesced
622 * @desc: pointer to descriptor
623 * @prev: previous request in desc, or NULL
624 * @req: this request
625 *
626 * Returns zero if @req cannot be coalesced into @desc, otherwise it returns
627 * the size of the request.
628 */
629size_t nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
630 struct nfs_page *prev, struct nfs_page *req)
631{
632 struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
633
634
635 if (mirror->pg_count > mirror->pg_bsize) {
636 /* should never happen */
637 WARN_ON_ONCE(1);
638 return 0;
639 }
640
641 /*
642 * Limit the request size so that we can still allocate a page array
643 * for it without upsetting the slab allocator.
644 */
645 if (((mirror->pg_count + req->wb_bytes) >> PAGE_SHIFT) *
646 sizeof(struct page *) > PAGE_SIZE)
647 return 0;
648
649 return min(mirror->pg_bsize - mirror->pg_count, (size_t)req->wb_bytes);
650}
651EXPORT_SYMBOL_GPL(nfs_generic_pg_test);
652
653struct nfs_pgio_header *nfs_pgio_header_alloc(const struct nfs_rw_ops *ops)
654{
655 struct nfs_pgio_header *hdr = ops->rw_alloc_header();
656
657 if (hdr) {
658 INIT_LIST_HEAD(&hdr->pages);
659 hdr->rw_ops = ops;
660 }
661 return hdr;
662}
663EXPORT_SYMBOL_GPL(nfs_pgio_header_alloc);
664
665/**
666 * nfs_pgio_data_destroy - make @hdr suitable for reuse
667 *
668 * Frees memory and releases refs from nfs_generic_pgio, so that it may
669 * be called again.
670 *
671 * @hdr: A header that has had nfs_generic_pgio called
672 */
673static void nfs_pgio_data_destroy(struct nfs_pgio_header *hdr)
674{
675 if (hdr->args.context)
676 put_nfs_open_context(hdr->args.context);
677 if (hdr->page_array.pagevec != hdr->page_array.page_array)
678 kfree(hdr->page_array.pagevec);
679}
680
681/*
682 * nfs_pgio_header_free - Free a read or write header
683 * @hdr: The header to free
684 */
685void nfs_pgio_header_free(struct nfs_pgio_header *hdr)
686{
687 nfs_pgio_data_destroy(hdr);
688 hdr->rw_ops->rw_free_header(hdr);
689}
690EXPORT_SYMBOL_GPL(nfs_pgio_header_free);
691
692/**
693 * nfs_pgio_rpcsetup - Set up arguments for a pageio call
694 * @hdr: The pageio hdr
695 * @count: Number of bytes to read
696 * @how: How to commit data (writes only)
697 * @cinfo: Commit information for the call (writes only)
698 */
699static void nfs_pgio_rpcsetup(struct nfs_pgio_header *hdr,
700 unsigned int count,
701 int how, struct nfs_commit_info *cinfo)
702{
703 struct nfs_page *req = hdr->req;
704
705 /* Set up the RPC argument and reply structs
706 * NB: take care not to mess about with hdr->commit et al. */
707
708 hdr->args.fh = NFS_FH(hdr->inode);
709 hdr->args.offset = req_offset(req);
710 /* pnfs_set_layoutcommit needs this */
711 hdr->mds_offset = hdr->args.offset;
712 hdr->args.pgbase = req->wb_pgbase;
713 hdr->args.pages = hdr->page_array.pagevec;
714 hdr->args.count = count;
715 hdr->args.context = get_nfs_open_context(nfs_req_openctx(req));
716 hdr->args.lock_context = req->wb_lock_context;
717 hdr->args.stable = NFS_UNSTABLE;
718 switch (how & (FLUSH_STABLE | FLUSH_COND_STABLE)) {
719 case 0:
720 break;
721 case FLUSH_COND_STABLE:
722 if (nfs_reqs_to_commit(cinfo))
723 break;
724 fallthrough;
725 default:
726 hdr->args.stable = NFS_FILE_SYNC;
727 }
728
729 hdr->res.fattr = &hdr->fattr;
730 hdr->res.count = 0;
731 hdr->res.eof = 0;
732 hdr->res.verf = &hdr->verf;
733 nfs_fattr_init(&hdr->fattr);
734}
735
736/**
737 * nfs_pgio_prepare - Prepare pageio hdr to go over the wire
738 * @task: The current task
739 * @calldata: pageio header to prepare
740 */
741static void nfs_pgio_prepare(struct rpc_task *task, void *calldata)
742{
743 struct nfs_pgio_header *hdr = calldata;
744 int err;
745 err = NFS_PROTO(hdr->inode)->pgio_rpc_prepare(task, hdr);
746 if (err)
747 rpc_exit(task, err);
748}
749
750int nfs_initiate_pgio(struct rpc_clnt *clnt, struct nfs_pgio_header *hdr,
751 const struct cred *cred, const struct nfs_rpc_ops *rpc_ops,
752 const struct rpc_call_ops *call_ops, int how, int flags)
753{
754 struct rpc_task *task;
755 struct rpc_message msg = {
756 .rpc_argp = &hdr->args,
757 .rpc_resp = &hdr->res,
758 .rpc_cred = cred,
759 };
760 struct rpc_task_setup task_setup_data = {
761 .rpc_client = clnt,
762 .task = &hdr->task,
763 .rpc_message = &msg,
764 .callback_ops = call_ops,
765 .callback_data = hdr,
766 .workqueue = nfsiod_workqueue,
767 .flags = RPC_TASK_ASYNC | flags,
768 };
769
770 if (nfs_server_capable(hdr->inode, NFS_CAP_MOVEABLE))
771 task_setup_data.flags |= RPC_TASK_MOVEABLE;
772
773 hdr->rw_ops->rw_initiate(hdr, &msg, rpc_ops, &task_setup_data, how);
774
775 dprintk("NFS: initiated pgio call "
776 "(req %s/%llu, %u bytes @ offset %llu)\n",
777 hdr->inode->i_sb->s_id,
778 (unsigned long long)NFS_FILEID(hdr->inode),
779 hdr->args.count,
780 (unsigned long long)hdr->args.offset);
781
782 task = rpc_run_task(&task_setup_data);
783 if (IS_ERR(task))
784 return PTR_ERR(task);
785 rpc_put_task(task);
786 return 0;
787}
788EXPORT_SYMBOL_GPL(nfs_initiate_pgio);
789
790/**
791 * nfs_pgio_error - Clean up from a pageio error
792 * @hdr: pageio header
793 */
794static void nfs_pgio_error(struct nfs_pgio_header *hdr)
795{
796 set_bit(NFS_IOHDR_REDO, &hdr->flags);
797 hdr->completion_ops->completion(hdr);
798}
799
800/**
801 * nfs_pgio_release - Release pageio data
802 * @calldata: The pageio header to release
803 */
804static void nfs_pgio_release(void *calldata)
805{
806 struct nfs_pgio_header *hdr = calldata;
807 hdr->completion_ops->completion(hdr);
808}
809
810static void nfs_pageio_mirror_init(struct nfs_pgio_mirror *mirror,
811 unsigned int bsize)
812{
813 INIT_LIST_HEAD(&mirror->pg_list);
814 mirror->pg_bytes_written = 0;
815 mirror->pg_count = 0;
816 mirror->pg_bsize = bsize;
817 mirror->pg_base = 0;
818 mirror->pg_recoalesce = 0;
819}
820
821/**
822 * nfs_pageio_init - initialise a page io descriptor
823 * @desc: pointer to descriptor
824 * @inode: pointer to inode
825 * @pg_ops: pointer to pageio operations
826 * @compl_ops: pointer to pageio completion operations
827 * @rw_ops: pointer to nfs read/write operations
828 * @bsize: io block size
829 * @io_flags: extra parameters for the io function
830 */
831void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
832 struct inode *inode,
833 const struct nfs_pageio_ops *pg_ops,
834 const struct nfs_pgio_completion_ops *compl_ops,
835 const struct nfs_rw_ops *rw_ops,
836 size_t bsize,
837 int io_flags)
838{
839 desc->pg_moreio = 0;
840 desc->pg_inode = inode;
841 desc->pg_ops = pg_ops;
842 desc->pg_completion_ops = compl_ops;
843 desc->pg_rw_ops = rw_ops;
844 desc->pg_ioflags = io_flags;
845 desc->pg_error = 0;
846 desc->pg_lseg = NULL;
847 desc->pg_io_completion = NULL;
848 desc->pg_dreq = NULL;
849 desc->pg_bsize = bsize;
850
851 desc->pg_mirror_count = 1;
852 desc->pg_mirror_idx = 0;
853
854 desc->pg_mirrors_dynamic = NULL;
855 desc->pg_mirrors = desc->pg_mirrors_static;
856 nfs_pageio_mirror_init(&desc->pg_mirrors[0], bsize);
857 desc->pg_maxretrans = 0;
858}
859
860/**
861 * nfs_pgio_result - Basic pageio error handling
862 * @task: The task that ran
863 * @calldata: Pageio header to check
864 */
865static void nfs_pgio_result(struct rpc_task *task, void *calldata)
866{
867 struct nfs_pgio_header *hdr = calldata;
868 struct inode *inode = hdr->inode;
869
870 if (hdr->rw_ops->rw_done(task, hdr, inode) != 0)
871 return;
872 if (task->tk_status < 0)
873 nfs_set_pgio_error(hdr, task->tk_status, hdr->args.offset);
874 else
875 hdr->rw_ops->rw_result(task, hdr);
876}
877
878/*
879 * Create an RPC task for the given read or write request and kick it.
880 * The page must have been locked by the caller.
881 *
882 * It may happen that the page we're passed is not marked dirty.
883 * This is the case if nfs_updatepage detects a conflicting request
884 * that has been written but not committed.
885 */
886int nfs_generic_pgio(struct nfs_pageio_descriptor *desc,
887 struct nfs_pgio_header *hdr)
888{
889 struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
890
891 struct nfs_page *req;
892 struct page **pages,
893 *last_page;
894 struct list_head *head = &mirror->pg_list;
895 struct nfs_commit_info cinfo;
896 struct nfs_page_array *pg_array = &hdr->page_array;
897 unsigned int pagecount, pageused;
898 gfp_t gfp_flags = nfs_io_gfp_mask();
899
900 pagecount = nfs_page_array_len(mirror->pg_base, mirror->pg_count);
901 pg_array->npages = pagecount;
902
903 if (pagecount <= ARRAY_SIZE(pg_array->page_array))
904 pg_array->pagevec = pg_array->page_array;
905 else {
906 pg_array->pagevec = kcalloc(pagecount, sizeof(struct page *), gfp_flags);
907 if (!pg_array->pagevec) {
908 pg_array->npages = 0;
909 nfs_pgio_error(hdr);
910 desc->pg_error = -ENOMEM;
911 return desc->pg_error;
912 }
913 }
914
915 nfs_init_cinfo(&cinfo, desc->pg_inode, desc->pg_dreq);
916 pages = hdr->page_array.pagevec;
917 last_page = NULL;
918 pageused = 0;
919 while (!list_empty(head)) {
920 req = nfs_list_entry(head->next);
921 nfs_list_move_request(req, &hdr->pages);
922
923 if (!last_page || last_page != req->wb_page) {
924 pageused++;
925 if (pageused > pagecount)
926 break;
927 *pages++ = last_page = req->wb_page;
928 }
929 }
930 if (WARN_ON_ONCE(pageused != pagecount)) {
931 nfs_pgio_error(hdr);
932 desc->pg_error = -EINVAL;
933 return desc->pg_error;
934 }
935
936 if ((desc->pg_ioflags & FLUSH_COND_STABLE) &&
937 (desc->pg_moreio || nfs_reqs_to_commit(&cinfo)))
938 desc->pg_ioflags &= ~FLUSH_COND_STABLE;
939
940 /* Set up the argument struct */
941 nfs_pgio_rpcsetup(hdr, mirror->pg_count, desc->pg_ioflags, &cinfo);
942 desc->pg_rpc_callops = &nfs_pgio_common_ops;
943 return 0;
944}
945EXPORT_SYMBOL_GPL(nfs_generic_pgio);
946
947static int nfs_generic_pg_pgios(struct nfs_pageio_descriptor *desc)
948{
949 struct nfs_pgio_header *hdr;
950 int ret;
951 unsigned short task_flags = 0;
952
953 hdr = nfs_pgio_header_alloc(desc->pg_rw_ops);
954 if (!hdr) {
955 desc->pg_error = -ENOMEM;
956 return desc->pg_error;
957 }
958 nfs_pgheader_init(desc, hdr, nfs_pgio_header_free);
959 ret = nfs_generic_pgio(desc, hdr);
960 if (ret == 0) {
961 if (NFS_SERVER(hdr->inode)->nfs_client->cl_minorversion)
962 task_flags = RPC_TASK_MOVEABLE;
963 ret = nfs_initiate_pgio(NFS_CLIENT(hdr->inode),
964 hdr,
965 hdr->cred,
966 NFS_PROTO(hdr->inode),
967 desc->pg_rpc_callops,
968 desc->pg_ioflags,
969 RPC_TASK_CRED_NOREF | task_flags);
970 }
971 return ret;
972}
973
974static struct nfs_pgio_mirror *
975nfs_pageio_alloc_mirrors(struct nfs_pageio_descriptor *desc,
976 unsigned int mirror_count)
977{
978 struct nfs_pgio_mirror *ret;
979 unsigned int i;
980
981 kfree(desc->pg_mirrors_dynamic);
982 desc->pg_mirrors_dynamic = NULL;
983 if (mirror_count == 1)
984 return desc->pg_mirrors_static;
985 ret = kmalloc_array(mirror_count, sizeof(*ret), nfs_io_gfp_mask());
986 if (ret != NULL) {
987 for (i = 0; i < mirror_count; i++)
988 nfs_pageio_mirror_init(&ret[i], desc->pg_bsize);
989 desc->pg_mirrors_dynamic = ret;
990 }
991 return ret;
992}
993
994/*
995 * nfs_pageio_setup_mirroring - determine if mirroring is to be used
996 * by calling the pg_get_mirror_count op
997 */
998static void nfs_pageio_setup_mirroring(struct nfs_pageio_descriptor *pgio,
999 struct nfs_page *req)
1000{
1001 unsigned int mirror_count = 1;
1002
1003 if (pgio->pg_ops->pg_get_mirror_count)
1004 mirror_count = pgio->pg_ops->pg_get_mirror_count(pgio, req);
1005 if (mirror_count == pgio->pg_mirror_count || pgio->pg_error < 0)
1006 return;
1007
1008 if (!mirror_count || mirror_count > NFS_PAGEIO_DESCRIPTOR_MIRROR_MAX) {
1009 pgio->pg_error = -EINVAL;
1010 return;
1011 }
1012
1013 pgio->pg_mirrors = nfs_pageio_alloc_mirrors(pgio, mirror_count);
1014 if (pgio->pg_mirrors == NULL) {
1015 pgio->pg_error = -ENOMEM;
1016 pgio->pg_mirrors = pgio->pg_mirrors_static;
1017 mirror_count = 1;
1018 }
1019 pgio->pg_mirror_count = mirror_count;
1020}
1021
1022static void nfs_pageio_cleanup_mirroring(struct nfs_pageio_descriptor *pgio)
1023{
1024 pgio->pg_mirror_count = 1;
1025 pgio->pg_mirror_idx = 0;
1026 pgio->pg_mirrors = pgio->pg_mirrors_static;
1027 kfree(pgio->pg_mirrors_dynamic);
1028 pgio->pg_mirrors_dynamic = NULL;
1029}
1030
1031static bool nfs_match_lock_context(const struct nfs_lock_context *l1,
1032 const struct nfs_lock_context *l2)
1033{
1034 return l1->lockowner == l2->lockowner;
1035}
1036
1037/**
1038 * nfs_coalesce_size - test two requests for compatibility
1039 * @prev: pointer to nfs_page
1040 * @req: pointer to nfs_page
1041 * @pgio: pointer to nfs_pagio_descriptor
1042 *
1043 * The nfs_page structures 'prev' and 'req' are compared to ensure that the
1044 * page data area they describe is contiguous, and that their RPC
1045 * credentials, NFSv4 open state, and lockowners are the same.
1046 *
1047 * Returns size of the request that can be coalesced
1048 */
1049static unsigned int nfs_coalesce_size(struct nfs_page *prev,
1050 struct nfs_page *req,
1051 struct nfs_pageio_descriptor *pgio)
1052{
1053 struct file_lock_context *flctx;
1054
1055 if (prev) {
1056 if (!nfs_match_open_context(nfs_req_openctx(req), nfs_req_openctx(prev)))
1057 return 0;
1058 flctx = locks_inode_context(d_inode(nfs_req_openctx(req)->dentry));
1059 if (flctx != NULL &&
1060 !(list_empty_careful(&flctx->flc_posix) &&
1061 list_empty_careful(&flctx->flc_flock)) &&
1062 !nfs_match_lock_context(req->wb_lock_context,
1063 prev->wb_lock_context))
1064 return 0;
1065 if (req_offset(req) != req_offset(prev) + prev->wb_bytes)
1066 return 0;
1067 if (req->wb_page == prev->wb_page) {
1068 if (req->wb_pgbase != prev->wb_pgbase + prev->wb_bytes)
1069 return 0;
1070 } else {
1071 if (req->wb_pgbase != 0 ||
1072 prev->wb_pgbase + prev->wb_bytes != PAGE_SIZE)
1073 return 0;
1074 }
1075 }
1076 return pgio->pg_ops->pg_test(pgio, prev, req);
1077}
1078
1079/**
1080 * nfs_pageio_do_add_request - Attempt to coalesce a request into a page list.
1081 * @desc: destination io descriptor
1082 * @req: request
1083 *
1084 * If the request 'req' was successfully coalesced into the existing list
1085 * of pages 'desc', it returns the size of req.
1086 */
1087static unsigned int
1088nfs_pageio_do_add_request(struct nfs_pageio_descriptor *desc,
1089 struct nfs_page *req)
1090{
1091 struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
1092 struct nfs_page *prev = NULL;
1093 unsigned int size;
1094
1095 if (list_empty(&mirror->pg_list)) {
1096 if (desc->pg_ops->pg_init)
1097 desc->pg_ops->pg_init(desc, req);
1098 if (desc->pg_error < 0)
1099 return 0;
1100 mirror->pg_base = req->wb_pgbase;
1101 mirror->pg_count = 0;
1102 mirror->pg_recoalesce = 0;
1103 } else
1104 prev = nfs_list_entry(mirror->pg_list.prev);
1105
1106 if (desc->pg_maxretrans && req->wb_nio > desc->pg_maxretrans) {
1107 if (NFS_SERVER(desc->pg_inode)->flags & NFS_MOUNT_SOFTERR)
1108 desc->pg_error = -ETIMEDOUT;
1109 else
1110 desc->pg_error = -EIO;
1111 return 0;
1112 }
1113
1114 size = nfs_coalesce_size(prev, req, desc);
1115 if (size < req->wb_bytes)
1116 return size;
1117 nfs_list_move_request(req, &mirror->pg_list);
1118 mirror->pg_count += req->wb_bytes;
1119 return req->wb_bytes;
1120}
1121
1122/*
1123 * Helper for nfs_pageio_add_request and nfs_pageio_complete
1124 */
1125static void nfs_pageio_doio(struct nfs_pageio_descriptor *desc)
1126{
1127 struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
1128
1129 if (!list_empty(&mirror->pg_list)) {
1130 int error = desc->pg_ops->pg_doio(desc);
1131 if (error < 0)
1132 desc->pg_error = error;
1133 if (list_empty(&mirror->pg_list))
1134 mirror->pg_bytes_written += mirror->pg_count;
1135 }
1136}
1137
1138static void
1139nfs_pageio_cleanup_request(struct nfs_pageio_descriptor *desc,
1140 struct nfs_page *req)
1141{
1142 LIST_HEAD(head);
1143
1144 nfs_list_move_request(req, &head);
1145 desc->pg_completion_ops->error_cleanup(&head, desc->pg_error);
1146}
1147
1148/**
1149 * __nfs_pageio_add_request - Attempt to coalesce a request into a page list.
1150 * @desc: destination io descriptor
1151 * @req: request
1152 *
1153 * This may split a request into subrequests which are all part of the
1154 * same page group. If so, it will submit @req as the last one, to ensure
1155 * the pointer to @req is still valid in case of failure.
1156 *
1157 * Returns true if the request 'req' was successfully coalesced into the
1158 * existing list of pages 'desc'.
1159 */
1160static int __nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
1161 struct nfs_page *req)
1162{
1163 struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
1164 struct nfs_page *subreq;
1165 unsigned int size, subreq_size;
1166
1167 nfs_page_group_lock(req);
1168
1169 subreq = req;
1170 subreq_size = subreq->wb_bytes;
1171 for(;;) {
1172 size = nfs_pageio_do_add_request(desc, subreq);
1173 if (size == subreq_size) {
1174 /* We successfully submitted a request */
1175 if (subreq == req)
1176 break;
1177 req->wb_pgbase += size;
1178 req->wb_bytes -= size;
1179 req->wb_offset += size;
1180 subreq_size = req->wb_bytes;
1181 subreq = req;
1182 continue;
1183 }
1184 if (WARN_ON_ONCE(subreq != req)) {
1185 nfs_page_group_unlock(req);
1186 nfs_pageio_cleanup_request(desc, subreq);
1187 subreq = req;
1188 subreq_size = req->wb_bytes;
1189 nfs_page_group_lock(req);
1190 }
1191 if (!size) {
1192 /* Can't coalesce any more, so do I/O */
1193 nfs_page_group_unlock(req);
1194 desc->pg_moreio = 1;
1195 nfs_pageio_doio(desc);
1196 if (desc->pg_error < 0 || mirror->pg_recoalesce)
1197 return 0;
1198 /* retry add_request for this subreq */
1199 nfs_page_group_lock(req);
1200 continue;
1201 }
1202 subreq = nfs_create_subreq(req, req->wb_pgbase,
1203 req->wb_offset, size);
1204 if (IS_ERR(subreq))
1205 goto err_ptr;
1206 subreq_size = size;
1207 }
1208
1209 nfs_page_group_unlock(req);
1210 return 1;
1211err_ptr:
1212 desc->pg_error = PTR_ERR(subreq);
1213 nfs_page_group_unlock(req);
1214 return 0;
1215}
1216
1217static int nfs_do_recoalesce(struct nfs_pageio_descriptor *desc)
1218{
1219 struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
1220 LIST_HEAD(head);
1221
1222 do {
1223 list_splice_init(&mirror->pg_list, &head);
1224 mirror->pg_recoalesce = 0;
1225
1226 while (!list_empty(&head)) {
1227 struct nfs_page *req;
1228
1229 req = list_first_entry(&head, struct nfs_page, wb_list);
1230 if (__nfs_pageio_add_request(desc, req))
1231 continue;
1232 if (desc->pg_error < 0) {
1233 list_splice_tail(&head, &mirror->pg_list);
1234 mirror->pg_recoalesce = 1;
1235 return 0;
1236 }
1237 break;
1238 }
1239 } while (mirror->pg_recoalesce);
1240 return 1;
1241}
1242
1243static int nfs_pageio_add_request_mirror(struct nfs_pageio_descriptor *desc,
1244 struct nfs_page *req)
1245{
1246 int ret;
1247
1248 do {
1249 ret = __nfs_pageio_add_request(desc, req);
1250 if (ret)
1251 break;
1252 if (desc->pg_error < 0)
1253 break;
1254 ret = nfs_do_recoalesce(desc);
1255 } while (ret);
1256
1257 return ret;
1258}
1259
1260static void nfs_pageio_error_cleanup(struct nfs_pageio_descriptor *desc)
1261{
1262 u32 midx;
1263 struct nfs_pgio_mirror *mirror;
1264
1265 if (!desc->pg_error)
1266 return;
1267
1268 for (midx = 0; midx < desc->pg_mirror_count; midx++) {
1269 mirror = nfs_pgio_get_mirror(desc, midx);
1270 desc->pg_completion_ops->error_cleanup(&mirror->pg_list,
1271 desc->pg_error);
1272 }
1273}
1274
1275int nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
1276 struct nfs_page *req)
1277{
1278 u32 midx;
1279 unsigned int pgbase, offset, bytes;
1280 struct nfs_page *dupreq;
1281
1282 pgbase = req->wb_pgbase;
1283 offset = req->wb_offset;
1284 bytes = req->wb_bytes;
1285
1286 nfs_pageio_setup_mirroring(desc, req);
1287 if (desc->pg_error < 0)
1288 goto out_failed;
1289
1290 /* Create the mirror instances first, and fire them off */
1291 for (midx = 1; midx < desc->pg_mirror_count; midx++) {
1292 nfs_page_group_lock(req);
1293
1294 dupreq = nfs_create_subreq(req,
1295 pgbase, offset, bytes);
1296
1297 nfs_page_group_unlock(req);
1298 if (IS_ERR(dupreq)) {
1299 desc->pg_error = PTR_ERR(dupreq);
1300 goto out_failed;
1301 }
1302
1303 nfs_pgio_set_current_mirror(desc, midx);
1304 if (!nfs_pageio_add_request_mirror(desc, dupreq))
1305 goto out_cleanup_subreq;
1306 }
1307
1308 nfs_pgio_set_current_mirror(desc, 0);
1309 if (!nfs_pageio_add_request_mirror(desc, req))
1310 goto out_failed;
1311
1312 return 1;
1313
1314out_cleanup_subreq:
1315 nfs_pageio_cleanup_request(desc, dupreq);
1316out_failed:
1317 nfs_pageio_error_cleanup(desc);
1318 return 0;
1319}
1320
1321/*
1322 * nfs_pageio_complete_mirror - Complete I/O on the current mirror of an
1323 * nfs_pageio_descriptor
1324 * @desc: pointer to io descriptor
1325 * @mirror_idx: pointer to mirror index
1326 */
1327static void nfs_pageio_complete_mirror(struct nfs_pageio_descriptor *desc,
1328 u32 mirror_idx)
1329{
1330 struct nfs_pgio_mirror *mirror;
1331 u32 restore_idx;
1332
1333 restore_idx = nfs_pgio_set_current_mirror(desc, mirror_idx);
1334 mirror = nfs_pgio_current_mirror(desc);
1335
1336 for (;;) {
1337 nfs_pageio_doio(desc);
1338 if (desc->pg_error < 0 || !mirror->pg_recoalesce)
1339 break;
1340 if (!nfs_do_recoalesce(desc))
1341 break;
1342 }
1343 nfs_pgio_set_current_mirror(desc, restore_idx);
1344}
1345
1346/*
1347 * nfs_pageio_resend - Transfer requests to new descriptor and resend
1348 * @hdr - the pgio header to move request from
1349 * @desc - the pageio descriptor to add requests to
1350 *
1351 * Try to move each request (nfs_page) from @hdr to @desc then attempt
1352 * to send them.
1353 *
1354 * Returns 0 on success and < 0 on error.
1355 */
1356int nfs_pageio_resend(struct nfs_pageio_descriptor *desc,
1357 struct nfs_pgio_header *hdr)
1358{
1359 LIST_HEAD(pages);
1360
1361 desc->pg_io_completion = hdr->io_completion;
1362 desc->pg_dreq = hdr->dreq;
1363 list_splice_init(&hdr->pages, &pages);
1364 while (!list_empty(&pages)) {
1365 struct nfs_page *req = nfs_list_entry(pages.next);
1366
1367 if (!nfs_pageio_add_request(desc, req))
1368 break;
1369 }
1370 nfs_pageio_complete(desc);
1371 if (!list_empty(&pages)) {
1372 int err = desc->pg_error < 0 ? desc->pg_error : -EIO;
1373 hdr->completion_ops->error_cleanup(&pages, err);
1374 nfs_set_pgio_error(hdr, err, hdr->io_start);
1375 return err;
1376 }
1377 return 0;
1378}
1379EXPORT_SYMBOL_GPL(nfs_pageio_resend);
1380
1381/**
1382 * nfs_pageio_complete - Complete I/O then cleanup an nfs_pageio_descriptor
1383 * @desc: pointer to io descriptor
1384 */
1385void nfs_pageio_complete(struct nfs_pageio_descriptor *desc)
1386{
1387 u32 midx;
1388
1389 for (midx = 0; midx < desc->pg_mirror_count; midx++)
1390 nfs_pageio_complete_mirror(desc, midx);
1391
1392 if (desc->pg_error < 0)
1393 nfs_pageio_error_cleanup(desc);
1394 if (desc->pg_ops->pg_cleanup)
1395 desc->pg_ops->pg_cleanup(desc);
1396 nfs_pageio_cleanup_mirroring(desc);
1397}
1398
1399/**
1400 * nfs_pageio_cond_complete - Conditional I/O completion
1401 * @desc: pointer to io descriptor
1402 * @index: page index
1403 *
1404 * It is important to ensure that processes don't try to take locks
1405 * on non-contiguous ranges of pages as that might deadlock. This
1406 * function should be called before attempting to wait on a locked
1407 * nfs_page. It will complete the I/O if the page index 'index'
1408 * is not contiguous with the existing list of pages in 'desc'.
1409 */
1410void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *desc, pgoff_t index)
1411{
1412 struct nfs_pgio_mirror *mirror;
1413 struct nfs_page *prev;
1414 u32 midx;
1415
1416 for (midx = 0; midx < desc->pg_mirror_count; midx++) {
1417 mirror = nfs_pgio_get_mirror(desc, midx);
1418 if (!list_empty(&mirror->pg_list)) {
1419 prev = nfs_list_entry(mirror->pg_list.prev);
1420 if (index != prev->wb_index + 1) {
1421 nfs_pageio_complete(desc);
1422 break;
1423 }
1424 }
1425 }
1426}
1427
1428/*
1429 * nfs_pageio_stop_mirroring - stop using mirroring (set mirror count to 1)
1430 */
1431void nfs_pageio_stop_mirroring(struct nfs_pageio_descriptor *pgio)
1432{
1433 nfs_pageio_complete(pgio);
1434}
1435
1436int __init nfs_init_nfspagecache(void)
1437{
1438 nfs_page_cachep = kmem_cache_create("nfs_page",
1439 sizeof(struct nfs_page),
1440 0, SLAB_HWCACHE_ALIGN,
1441 NULL);
1442 if (nfs_page_cachep == NULL)
1443 return -ENOMEM;
1444
1445 return 0;
1446}
1447
1448void nfs_destroy_nfspagecache(void)
1449{
1450 kmem_cache_destroy(nfs_page_cachep);
1451}
1452
1453static const struct rpc_call_ops nfs_pgio_common_ops = {
1454 .rpc_call_prepare = nfs_pgio_prepare,
1455 .rpc_call_done = nfs_pgio_result,
1456 .rpc_release = nfs_pgio_release,
1457};
1458
1459const struct nfs_pageio_ops nfs_pgio_rw_ops = {
1460 .pg_test = nfs_generic_pg_test,
1461 .pg_doio = nfs_generic_pg_pgios,
1462};