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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 *
94nfs_page_alloc(void)
95{
96 struct nfs_page *p = kmem_cache_zalloc(nfs_page_cachep, GFP_KERNEL);
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 smp_mb__before_atomic();
275 clear_bit(PG_HEADLOCK, &req->wb_flags);
276 smp_mb__after_atomic();
277 if (!test_bit(PG_CONTENDED1, &req->wb_flags))
278 return;
279 wake_up_bit(&req->wb_flags, PG_HEADLOCK);
280}
281
282/*
283 * nfs_page_group_lock - lock the head of the page group
284 * @req: request in group that is to be locked
285 *
286 * this lock must be held when traversing or modifying the page
287 * group list
288 *
289 * return 0 on success, < 0 on error
290 */
291int
292nfs_page_group_lock(struct nfs_page *req)
293{
294 int ret;
295
296 ret = nfs_page_set_headlock(req);
297 if (ret || req->wb_head == req)
298 return ret;
299 return nfs_page_set_headlock(req->wb_head);
300}
301
302/*
303 * nfs_page_group_unlock - unlock the head of the page group
304 * @req: request in group that is to be unlocked
305 */
306void
307nfs_page_group_unlock(struct nfs_page *req)
308{
309 if (req != req->wb_head)
310 nfs_page_clear_headlock(req->wb_head);
311 nfs_page_clear_headlock(req);
312}
313
314/*
315 * nfs_page_group_sync_on_bit_locked
316 *
317 * must be called with page group lock held
318 */
319static bool
320nfs_page_group_sync_on_bit_locked(struct nfs_page *req, unsigned int bit)
321{
322 struct nfs_page *head = req->wb_head;
323 struct nfs_page *tmp;
324
325 WARN_ON_ONCE(!test_bit(PG_HEADLOCK, &head->wb_flags));
326 WARN_ON_ONCE(test_and_set_bit(bit, &req->wb_flags));
327
328 tmp = req->wb_this_page;
329 while (tmp != req) {
330 if (!test_bit(bit, &tmp->wb_flags))
331 return false;
332 tmp = tmp->wb_this_page;
333 }
334
335 /* true! reset all bits */
336 tmp = req;
337 do {
338 clear_bit(bit, &tmp->wb_flags);
339 tmp = tmp->wb_this_page;
340 } while (tmp != req);
341
342 return true;
343}
344
345/*
346 * nfs_page_group_sync_on_bit - set bit on current request, but only
347 * return true if the bit is set for all requests in page group
348 * @req - request in page group
349 * @bit - PG_* bit that is used to sync page group
350 */
351bool nfs_page_group_sync_on_bit(struct nfs_page *req, unsigned int bit)
352{
353 bool ret;
354
355 nfs_page_group_lock(req);
356 ret = nfs_page_group_sync_on_bit_locked(req, bit);
357 nfs_page_group_unlock(req);
358
359 return ret;
360}
361
362/*
363 * nfs_page_group_init - Initialize the page group linkage for @req
364 * @req - a new nfs request
365 * @prev - the previous request in page group, or NULL if @req is the first
366 * or only request in the group (the head).
367 */
368static inline void
369nfs_page_group_init(struct nfs_page *req, struct nfs_page *prev)
370{
371 struct inode *inode;
372 WARN_ON_ONCE(prev == req);
373
374 if (!prev) {
375 /* a head request */
376 req->wb_head = req;
377 req->wb_this_page = req;
378 } else {
379 /* a subrequest */
380 WARN_ON_ONCE(prev->wb_this_page != prev->wb_head);
381 WARN_ON_ONCE(!test_bit(PG_HEADLOCK, &prev->wb_head->wb_flags));
382 req->wb_head = prev->wb_head;
383 req->wb_this_page = prev->wb_this_page;
384 prev->wb_this_page = req;
385
386 /* All subrequests take a ref on the head request until
387 * nfs_page_group_destroy is called */
388 kref_get(&req->wb_head->wb_kref);
389
390 /* grab extra ref and bump the request count if head request
391 * has extra ref from the write/commit path to handle handoff
392 * between write and commit lists. */
393 if (test_bit(PG_INODE_REF, &prev->wb_head->wb_flags)) {
394 inode = page_file_mapping(req->wb_page)->host;
395 set_bit(PG_INODE_REF, &req->wb_flags);
396 kref_get(&req->wb_kref);
397 atomic_long_inc(&NFS_I(inode)->nrequests);
398 }
399 }
400}
401
402/*
403 * nfs_page_group_destroy - sync the destruction of page groups
404 * @req - request that no longer needs the page group
405 *
406 * releases the page group reference from each member once all
407 * members have called this function.
408 */
409static void
410nfs_page_group_destroy(struct kref *kref)
411{
412 struct nfs_page *req = container_of(kref, struct nfs_page, wb_kref);
413 struct nfs_page *head = req->wb_head;
414 struct nfs_page *tmp, *next;
415
416 if (!nfs_page_group_sync_on_bit(req, PG_TEARDOWN))
417 goto out;
418
419 tmp = req;
420 do {
421 next = tmp->wb_this_page;
422 /* unlink and free */
423 tmp->wb_this_page = tmp;
424 tmp->wb_head = tmp;
425 nfs_free_request(tmp);
426 tmp = next;
427 } while (tmp != req);
428out:
429 /* subrequests must release the ref on the head request */
430 if (head != req)
431 nfs_release_request(head);
432}
433
434static struct nfs_page *
435__nfs_create_request(struct nfs_lock_context *l_ctx, struct page *page,
436 unsigned int pgbase, unsigned int offset,
437 unsigned int count)
438{
439 struct nfs_page *req;
440 struct nfs_open_context *ctx = l_ctx->open_context;
441
442 if (test_bit(NFS_CONTEXT_BAD, &ctx->flags))
443 return ERR_PTR(-EBADF);
444 /* try to allocate the request struct */
445 req = nfs_page_alloc();
446 if (req == NULL)
447 return ERR_PTR(-ENOMEM);
448
449 req->wb_lock_context = l_ctx;
450 refcount_inc(&l_ctx->count);
451 atomic_inc(&l_ctx->io_count);
452
453 /* Initialize the request struct. Initially, we assume a
454 * long write-back delay. This will be adjusted in
455 * update_nfs_request below if the region is not locked. */
456 req->wb_page = page;
457 if (page) {
458 req->wb_index = page_index(page);
459 get_page(page);
460 }
461 req->wb_offset = offset;
462 req->wb_pgbase = pgbase;
463 req->wb_bytes = count;
464 kref_init(&req->wb_kref);
465 req->wb_nio = 0;
466 return req;
467}
468
469/**
470 * nfs_create_request - Create an NFS read/write request.
471 * @ctx: open context to use
472 * @page: page to write
473 * @offset: starting offset within the page for the write
474 * @count: number of bytes to read/write
475 *
476 * The page must be locked by the caller. This makes sure we never
477 * create two different requests for the same page.
478 * User should ensure it is safe to sleep in this function.
479 */
480struct nfs_page *
481nfs_create_request(struct nfs_open_context *ctx, struct page *page,
482 unsigned int offset, unsigned int count)
483{
484 struct nfs_lock_context *l_ctx = nfs_get_lock_context(ctx);
485 struct nfs_page *ret;
486
487 if (IS_ERR(l_ctx))
488 return ERR_CAST(l_ctx);
489 ret = __nfs_create_request(l_ctx, page, offset, offset, count);
490 if (!IS_ERR(ret))
491 nfs_page_group_init(ret, NULL);
492 nfs_put_lock_context(l_ctx);
493 return ret;
494}
495
496static struct nfs_page *
497nfs_create_subreq(struct nfs_page *req,
498 unsigned int pgbase,
499 unsigned int offset,
500 unsigned int count)
501{
502 struct nfs_page *last;
503 struct nfs_page *ret;
504
505 ret = __nfs_create_request(req->wb_lock_context, req->wb_page,
506 pgbase, offset, count);
507 if (!IS_ERR(ret)) {
508 /* find the last request */
509 for (last = req->wb_head;
510 last->wb_this_page != req->wb_head;
511 last = last->wb_this_page)
512 ;
513
514 nfs_lock_request(ret);
515 ret->wb_index = req->wb_index;
516 nfs_page_group_init(ret, last);
517 ret->wb_nio = req->wb_nio;
518 }
519 return ret;
520}
521
522/**
523 * nfs_unlock_request - Unlock request and wake up sleepers.
524 * @req: pointer to request
525 */
526void nfs_unlock_request(struct nfs_page *req)
527{
528 if (!NFS_WBACK_BUSY(req)) {
529 printk(KERN_ERR "NFS: Invalid unlock attempted\n");
530 BUG();
531 }
532 smp_mb__before_atomic();
533 clear_bit(PG_BUSY, &req->wb_flags);
534 smp_mb__after_atomic();
535 if (!test_bit(PG_CONTENDED2, &req->wb_flags))
536 return;
537 wake_up_bit(&req->wb_flags, PG_BUSY);
538}
539
540/**
541 * nfs_unlock_and_release_request - Unlock request and release the nfs_page
542 * @req: pointer to request
543 */
544void nfs_unlock_and_release_request(struct nfs_page *req)
545{
546 nfs_unlock_request(req);
547 nfs_release_request(req);
548}
549
550/*
551 * nfs_clear_request - Free up all resources allocated to the request
552 * @req:
553 *
554 * Release page and open context resources associated with a read/write
555 * request after it has completed.
556 */
557static void nfs_clear_request(struct nfs_page *req)
558{
559 struct page *page = req->wb_page;
560 struct nfs_lock_context *l_ctx = req->wb_lock_context;
561 struct nfs_open_context *ctx;
562
563 if (page != NULL) {
564 put_page(page);
565 req->wb_page = NULL;
566 }
567 if (l_ctx != NULL) {
568 if (atomic_dec_and_test(&l_ctx->io_count)) {
569 wake_up_var(&l_ctx->io_count);
570 ctx = l_ctx->open_context;
571 if (test_bit(NFS_CONTEXT_UNLOCK, &ctx->flags))
572 rpc_wake_up(&NFS_SERVER(d_inode(ctx->dentry))->uoc_rpcwaitq);
573 }
574 nfs_put_lock_context(l_ctx);
575 req->wb_lock_context = NULL;
576 }
577}
578
579/**
580 * nfs_free_request - Release the count on an NFS read/write request
581 * @req: request to release
582 *
583 * Note: Should never be called with the spinlock held!
584 */
585void nfs_free_request(struct nfs_page *req)
586{
587 WARN_ON_ONCE(req->wb_this_page != req);
588
589 /* extra debug: make sure no sync bits are still set */
590 WARN_ON_ONCE(test_bit(PG_TEARDOWN, &req->wb_flags));
591 WARN_ON_ONCE(test_bit(PG_UNLOCKPAGE, &req->wb_flags));
592 WARN_ON_ONCE(test_bit(PG_UPTODATE, &req->wb_flags));
593 WARN_ON_ONCE(test_bit(PG_WB_END, &req->wb_flags));
594 WARN_ON_ONCE(test_bit(PG_REMOVE, &req->wb_flags));
595
596 /* Release struct file and open context */
597 nfs_clear_request(req);
598 nfs_page_free(req);
599}
600
601void nfs_release_request(struct nfs_page *req)
602{
603 kref_put(&req->wb_kref, nfs_page_group_destroy);
604}
605EXPORT_SYMBOL_GPL(nfs_release_request);
606
607/**
608 * nfs_wait_on_request - Wait for a request to complete.
609 * @req: request to wait upon.
610 *
611 * Interruptible by fatal signals only.
612 * The user is responsible for holding a count on the request.
613 */
614int
615nfs_wait_on_request(struct nfs_page *req)
616{
617 if (!test_bit(PG_BUSY, &req->wb_flags))
618 return 0;
619 set_bit(PG_CONTENDED2, &req->wb_flags);
620 smp_mb__after_atomic();
621 return wait_on_bit_io(&req->wb_flags, PG_BUSY,
622 TASK_UNINTERRUPTIBLE);
623}
624EXPORT_SYMBOL_GPL(nfs_wait_on_request);
625
626/*
627 * nfs_generic_pg_test - determine if requests can be coalesced
628 * @desc: pointer to descriptor
629 * @prev: previous request in desc, or NULL
630 * @req: this request
631 *
632 * Returns zero if @req cannot be coalesced into @desc, otherwise it returns
633 * the size of the request.
634 */
635size_t nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
636 struct nfs_page *prev, struct nfs_page *req)
637{
638 struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
639
640
641 if (mirror->pg_count > mirror->pg_bsize) {
642 /* should never happen */
643 WARN_ON_ONCE(1);
644 return 0;
645 }
646
647 /*
648 * Limit the request size so that we can still allocate a page array
649 * for it without upsetting the slab allocator.
650 */
651 if (((mirror->pg_count + req->wb_bytes) >> PAGE_SHIFT) *
652 sizeof(struct page *) > PAGE_SIZE)
653 return 0;
654
655 return min(mirror->pg_bsize - mirror->pg_count, (size_t)req->wb_bytes);
656}
657EXPORT_SYMBOL_GPL(nfs_generic_pg_test);
658
659struct nfs_pgio_header *nfs_pgio_header_alloc(const struct nfs_rw_ops *ops)
660{
661 struct nfs_pgio_header *hdr = ops->rw_alloc_header();
662
663 if (hdr) {
664 INIT_LIST_HEAD(&hdr->pages);
665 hdr->rw_ops = ops;
666 }
667 return hdr;
668}
669EXPORT_SYMBOL_GPL(nfs_pgio_header_alloc);
670
671/**
672 * nfs_pgio_data_destroy - make @hdr suitable for reuse
673 *
674 * Frees memory and releases refs from nfs_generic_pgio, so that it may
675 * be called again.
676 *
677 * @hdr: A header that has had nfs_generic_pgio called
678 */
679static void nfs_pgio_data_destroy(struct nfs_pgio_header *hdr)
680{
681 if (hdr->args.context)
682 put_nfs_open_context(hdr->args.context);
683 if (hdr->page_array.pagevec != hdr->page_array.page_array)
684 kfree(hdr->page_array.pagevec);
685}
686
687/*
688 * nfs_pgio_header_free - Free a read or write header
689 * @hdr: The header to free
690 */
691void nfs_pgio_header_free(struct nfs_pgio_header *hdr)
692{
693 nfs_pgio_data_destroy(hdr);
694 hdr->rw_ops->rw_free_header(hdr);
695}
696EXPORT_SYMBOL_GPL(nfs_pgio_header_free);
697
698/**
699 * nfs_pgio_rpcsetup - Set up arguments for a pageio call
700 * @hdr: The pageio hdr
701 * @count: Number of bytes to read
702 * @how: How to commit data (writes only)
703 * @cinfo: Commit information for the call (writes only)
704 */
705static void nfs_pgio_rpcsetup(struct nfs_pgio_header *hdr,
706 unsigned int count,
707 int how, struct nfs_commit_info *cinfo)
708{
709 struct nfs_page *req = hdr->req;
710
711 /* Set up the RPC argument and reply structs
712 * NB: take care not to mess about with hdr->commit et al. */
713
714 hdr->args.fh = NFS_FH(hdr->inode);
715 hdr->args.offset = req_offset(req);
716 /* pnfs_set_layoutcommit needs this */
717 hdr->mds_offset = hdr->args.offset;
718 hdr->args.pgbase = req->wb_pgbase;
719 hdr->args.pages = hdr->page_array.pagevec;
720 hdr->args.count = count;
721 hdr->args.context = get_nfs_open_context(nfs_req_openctx(req));
722 hdr->args.lock_context = req->wb_lock_context;
723 hdr->args.stable = NFS_UNSTABLE;
724 switch (how & (FLUSH_STABLE | FLUSH_COND_STABLE)) {
725 case 0:
726 break;
727 case FLUSH_COND_STABLE:
728 if (nfs_reqs_to_commit(cinfo))
729 break;
730 fallthrough;
731 default:
732 hdr->args.stable = NFS_FILE_SYNC;
733 }
734
735 hdr->res.fattr = &hdr->fattr;
736 hdr->res.count = 0;
737 hdr->res.eof = 0;
738 hdr->res.verf = &hdr->verf;
739 nfs_fattr_init(&hdr->fattr);
740}
741
742/**
743 * nfs_pgio_prepare - Prepare pageio hdr to go over the wire
744 * @task: The current task
745 * @calldata: pageio header to prepare
746 */
747static void nfs_pgio_prepare(struct rpc_task *task, void *calldata)
748{
749 struct nfs_pgio_header *hdr = calldata;
750 int err;
751 err = NFS_PROTO(hdr->inode)->pgio_rpc_prepare(task, hdr);
752 if (err)
753 rpc_exit(task, err);
754}
755
756int nfs_initiate_pgio(struct rpc_clnt *clnt, struct nfs_pgio_header *hdr,
757 const struct cred *cred, const struct nfs_rpc_ops *rpc_ops,
758 const struct rpc_call_ops *call_ops, int how, int flags)
759{
760 struct rpc_task *task;
761 struct rpc_message msg = {
762 .rpc_argp = &hdr->args,
763 .rpc_resp = &hdr->res,
764 .rpc_cred = cred,
765 };
766 struct rpc_task_setup task_setup_data = {
767 .rpc_client = clnt,
768 .task = &hdr->task,
769 .rpc_message = &msg,
770 .callback_ops = call_ops,
771 .callback_data = hdr,
772 .workqueue = nfsiod_workqueue,
773 .flags = RPC_TASK_ASYNC | flags,
774 };
775
776 hdr->rw_ops->rw_initiate(hdr, &msg, rpc_ops, &task_setup_data, how);
777
778 dprintk("NFS: initiated pgio call "
779 "(req %s/%llu, %u bytes @ offset %llu)\n",
780 hdr->inode->i_sb->s_id,
781 (unsigned long long)NFS_FILEID(hdr->inode),
782 hdr->args.count,
783 (unsigned long long)hdr->args.offset);
784
785 task = rpc_run_task(&task_setup_data);
786 if (IS_ERR(task))
787 return PTR_ERR(task);
788 rpc_put_task(task);
789 return 0;
790}
791EXPORT_SYMBOL_GPL(nfs_initiate_pgio);
792
793/**
794 * nfs_pgio_error - Clean up from a pageio error
795 * @hdr: pageio header
796 */
797static void nfs_pgio_error(struct nfs_pgio_header *hdr)
798{
799 set_bit(NFS_IOHDR_REDO, &hdr->flags);
800 hdr->completion_ops->completion(hdr);
801}
802
803/**
804 * nfs_pgio_release - Release pageio data
805 * @calldata: The pageio header to release
806 */
807static void nfs_pgio_release(void *calldata)
808{
809 struct nfs_pgio_header *hdr = calldata;
810 hdr->completion_ops->completion(hdr);
811}
812
813static void nfs_pageio_mirror_init(struct nfs_pgio_mirror *mirror,
814 unsigned int bsize)
815{
816 INIT_LIST_HEAD(&mirror->pg_list);
817 mirror->pg_bytes_written = 0;
818 mirror->pg_count = 0;
819 mirror->pg_bsize = bsize;
820 mirror->pg_base = 0;
821 mirror->pg_recoalesce = 0;
822}
823
824/**
825 * nfs_pageio_init - initialise a page io descriptor
826 * @desc: pointer to descriptor
827 * @inode: pointer to inode
828 * @pg_ops: pointer to pageio operations
829 * @compl_ops: pointer to pageio completion operations
830 * @rw_ops: pointer to nfs read/write operations
831 * @bsize: io block size
832 * @io_flags: extra parameters for the io function
833 */
834void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
835 struct inode *inode,
836 const struct nfs_pageio_ops *pg_ops,
837 const struct nfs_pgio_completion_ops *compl_ops,
838 const struct nfs_rw_ops *rw_ops,
839 size_t bsize,
840 int io_flags)
841{
842 desc->pg_moreio = 0;
843 desc->pg_inode = inode;
844 desc->pg_ops = pg_ops;
845 desc->pg_completion_ops = compl_ops;
846 desc->pg_rw_ops = rw_ops;
847 desc->pg_ioflags = io_flags;
848 desc->pg_error = 0;
849 desc->pg_lseg = NULL;
850 desc->pg_io_completion = NULL;
851 desc->pg_dreq = NULL;
852 desc->pg_bsize = bsize;
853
854 desc->pg_mirror_count = 1;
855 desc->pg_mirror_idx = 0;
856
857 desc->pg_mirrors_dynamic = NULL;
858 desc->pg_mirrors = desc->pg_mirrors_static;
859 nfs_pageio_mirror_init(&desc->pg_mirrors[0], bsize);
860 desc->pg_maxretrans = 0;
861}
862
863/**
864 * nfs_pgio_result - Basic pageio error handling
865 * @task: The task that ran
866 * @calldata: Pageio header to check
867 */
868static void nfs_pgio_result(struct rpc_task *task, void *calldata)
869{
870 struct nfs_pgio_header *hdr = calldata;
871 struct inode *inode = hdr->inode;
872
873 dprintk("NFS: %s: %5u, (status %d)\n", __func__,
874 task->tk_pid, task->tk_status);
875
876 if (hdr->rw_ops->rw_done(task, hdr, inode) != 0)
877 return;
878 if (task->tk_status < 0)
879 nfs_set_pgio_error(hdr, task->tk_status, hdr->args.offset);
880 else
881 hdr->rw_ops->rw_result(task, hdr);
882}
883
884/*
885 * Create an RPC task for the given read or write request and kick it.
886 * The page must have been locked by the caller.
887 *
888 * It may happen that the page we're passed is not marked dirty.
889 * This is the case if nfs_updatepage detects a conflicting request
890 * that has been written but not committed.
891 */
892int nfs_generic_pgio(struct nfs_pageio_descriptor *desc,
893 struct nfs_pgio_header *hdr)
894{
895 struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
896
897 struct nfs_page *req;
898 struct page **pages,
899 *last_page;
900 struct list_head *head = &mirror->pg_list;
901 struct nfs_commit_info cinfo;
902 struct nfs_page_array *pg_array = &hdr->page_array;
903 unsigned int pagecount, pageused;
904 gfp_t gfp_flags = GFP_KERNEL;
905
906 pagecount = nfs_page_array_len(mirror->pg_base, mirror->pg_count);
907 pg_array->npages = pagecount;
908
909 if (pagecount <= ARRAY_SIZE(pg_array->page_array))
910 pg_array->pagevec = pg_array->page_array;
911 else {
912 pg_array->pagevec = kcalloc(pagecount, sizeof(struct page *), gfp_flags);
913 if (!pg_array->pagevec) {
914 pg_array->npages = 0;
915 nfs_pgio_error(hdr);
916 desc->pg_error = -ENOMEM;
917 return desc->pg_error;
918 }
919 }
920
921 nfs_init_cinfo(&cinfo, desc->pg_inode, desc->pg_dreq);
922 pages = hdr->page_array.pagevec;
923 last_page = NULL;
924 pageused = 0;
925 while (!list_empty(head)) {
926 req = nfs_list_entry(head->next);
927 nfs_list_move_request(req, &hdr->pages);
928
929 if (!last_page || last_page != req->wb_page) {
930 pageused++;
931 if (pageused > pagecount)
932 break;
933 *pages++ = last_page = req->wb_page;
934 }
935 }
936 if (WARN_ON_ONCE(pageused != pagecount)) {
937 nfs_pgio_error(hdr);
938 desc->pg_error = -EINVAL;
939 return desc->pg_error;
940 }
941
942 if ((desc->pg_ioflags & FLUSH_COND_STABLE) &&
943 (desc->pg_moreio || nfs_reqs_to_commit(&cinfo)))
944 desc->pg_ioflags &= ~FLUSH_COND_STABLE;
945
946 /* Set up the argument struct */
947 nfs_pgio_rpcsetup(hdr, mirror->pg_count, desc->pg_ioflags, &cinfo);
948 desc->pg_rpc_callops = &nfs_pgio_common_ops;
949 return 0;
950}
951EXPORT_SYMBOL_GPL(nfs_generic_pgio);
952
953static int nfs_generic_pg_pgios(struct nfs_pageio_descriptor *desc)
954{
955 struct nfs_pgio_header *hdr;
956 int ret;
957 unsigned short task_flags = 0;
958
959 hdr = nfs_pgio_header_alloc(desc->pg_rw_ops);
960 if (!hdr) {
961 desc->pg_error = -ENOMEM;
962 return desc->pg_error;
963 }
964 nfs_pgheader_init(desc, hdr, nfs_pgio_header_free);
965 ret = nfs_generic_pgio(desc, hdr);
966 if (ret == 0) {
967 if (NFS_SERVER(hdr->inode)->nfs_client->cl_minorversion)
968 task_flags = RPC_TASK_MOVEABLE;
969 ret = nfs_initiate_pgio(NFS_CLIENT(hdr->inode),
970 hdr,
971 hdr->cred,
972 NFS_PROTO(hdr->inode),
973 desc->pg_rpc_callops,
974 desc->pg_ioflags,
975 RPC_TASK_CRED_NOREF | task_flags);
976 }
977 return ret;
978}
979
980static struct nfs_pgio_mirror *
981nfs_pageio_alloc_mirrors(struct nfs_pageio_descriptor *desc,
982 unsigned int mirror_count)
983{
984 struct nfs_pgio_mirror *ret;
985 unsigned int i;
986
987 kfree(desc->pg_mirrors_dynamic);
988 desc->pg_mirrors_dynamic = NULL;
989 if (mirror_count == 1)
990 return desc->pg_mirrors_static;
991 ret = kmalloc_array(mirror_count, sizeof(*ret), GFP_KERNEL);
992 if (ret != NULL) {
993 for (i = 0; i < mirror_count; i++)
994 nfs_pageio_mirror_init(&ret[i], desc->pg_bsize);
995 desc->pg_mirrors_dynamic = ret;
996 }
997 return ret;
998}
999
1000/*
1001 * nfs_pageio_setup_mirroring - determine if mirroring is to be used
1002 * by calling the pg_get_mirror_count op
1003 */
1004static void nfs_pageio_setup_mirroring(struct nfs_pageio_descriptor *pgio,
1005 struct nfs_page *req)
1006{
1007 unsigned int mirror_count = 1;
1008
1009 if (pgio->pg_ops->pg_get_mirror_count)
1010 mirror_count = pgio->pg_ops->pg_get_mirror_count(pgio, req);
1011 if (mirror_count == pgio->pg_mirror_count || pgio->pg_error < 0)
1012 return;
1013
1014 if (!mirror_count || mirror_count > NFS_PAGEIO_DESCRIPTOR_MIRROR_MAX) {
1015 pgio->pg_error = -EINVAL;
1016 return;
1017 }
1018
1019 pgio->pg_mirrors = nfs_pageio_alloc_mirrors(pgio, mirror_count);
1020 if (pgio->pg_mirrors == NULL) {
1021 pgio->pg_error = -ENOMEM;
1022 pgio->pg_mirrors = pgio->pg_mirrors_static;
1023 mirror_count = 1;
1024 }
1025 pgio->pg_mirror_count = mirror_count;
1026}
1027
1028static void nfs_pageio_cleanup_mirroring(struct nfs_pageio_descriptor *pgio)
1029{
1030 pgio->pg_mirror_count = 1;
1031 pgio->pg_mirror_idx = 0;
1032 pgio->pg_mirrors = pgio->pg_mirrors_static;
1033 kfree(pgio->pg_mirrors_dynamic);
1034 pgio->pg_mirrors_dynamic = NULL;
1035}
1036
1037static bool nfs_match_lock_context(const struct nfs_lock_context *l1,
1038 const struct nfs_lock_context *l2)
1039{
1040 return l1->lockowner == l2->lockowner;
1041}
1042
1043/**
1044 * nfs_coalesce_size - test two requests for compatibility
1045 * @prev: pointer to nfs_page
1046 * @req: pointer to nfs_page
1047 * @pgio: pointer to nfs_pagio_descriptor
1048 *
1049 * The nfs_page structures 'prev' and 'req' are compared to ensure that the
1050 * page data area they describe is contiguous, and that their RPC
1051 * credentials, NFSv4 open state, and lockowners are the same.
1052 *
1053 * Returns size of the request that can be coalesced
1054 */
1055static unsigned int nfs_coalesce_size(struct nfs_page *prev,
1056 struct nfs_page *req,
1057 struct nfs_pageio_descriptor *pgio)
1058{
1059 struct file_lock_context *flctx;
1060
1061 if (prev) {
1062 if (!nfs_match_open_context(nfs_req_openctx(req), nfs_req_openctx(prev)))
1063 return 0;
1064 flctx = d_inode(nfs_req_openctx(req)->dentry)->i_flctx;
1065 if (flctx != NULL &&
1066 !(list_empty_careful(&flctx->flc_posix) &&
1067 list_empty_careful(&flctx->flc_flock)) &&
1068 !nfs_match_lock_context(req->wb_lock_context,
1069 prev->wb_lock_context))
1070 return 0;
1071 if (req_offset(req) != req_offset(prev) + prev->wb_bytes)
1072 return 0;
1073 if (req->wb_page == prev->wb_page) {
1074 if (req->wb_pgbase != prev->wb_pgbase + prev->wb_bytes)
1075 return 0;
1076 } else {
1077 if (req->wb_pgbase != 0 ||
1078 prev->wb_pgbase + prev->wb_bytes != PAGE_SIZE)
1079 return 0;
1080 }
1081 }
1082 return pgio->pg_ops->pg_test(pgio, prev, req);
1083}
1084
1085/**
1086 * nfs_pageio_do_add_request - Attempt to coalesce a request into a page list.
1087 * @desc: destination io descriptor
1088 * @req: request
1089 *
1090 * If the request 'req' was successfully coalesced into the existing list
1091 * of pages 'desc', it returns the size of req.
1092 */
1093static unsigned int
1094nfs_pageio_do_add_request(struct nfs_pageio_descriptor *desc,
1095 struct nfs_page *req)
1096{
1097 struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
1098 struct nfs_page *prev = NULL;
1099 unsigned int size;
1100
1101 if (list_empty(&mirror->pg_list)) {
1102 if (desc->pg_ops->pg_init)
1103 desc->pg_ops->pg_init(desc, req);
1104 if (desc->pg_error < 0)
1105 return 0;
1106 mirror->pg_base = req->wb_pgbase;
1107 mirror->pg_count = 0;
1108 mirror->pg_recoalesce = 0;
1109 } else
1110 prev = nfs_list_entry(mirror->pg_list.prev);
1111
1112 if (desc->pg_maxretrans && req->wb_nio > desc->pg_maxretrans) {
1113 if (NFS_SERVER(desc->pg_inode)->flags & NFS_MOUNT_SOFTERR)
1114 desc->pg_error = -ETIMEDOUT;
1115 else
1116 desc->pg_error = -EIO;
1117 return 0;
1118 }
1119
1120 size = nfs_coalesce_size(prev, req, desc);
1121 if (size < req->wb_bytes)
1122 return size;
1123 nfs_list_move_request(req, &mirror->pg_list);
1124 mirror->pg_count += req->wb_bytes;
1125 return req->wb_bytes;
1126}
1127
1128/*
1129 * Helper for nfs_pageio_add_request and nfs_pageio_complete
1130 */
1131static void nfs_pageio_doio(struct nfs_pageio_descriptor *desc)
1132{
1133 struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
1134
1135 if (!list_empty(&mirror->pg_list)) {
1136 int error = desc->pg_ops->pg_doio(desc);
1137 if (error < 0)
1138 desc->pg_error = error;
1139 if (list_empty(&mirror->pg_list))
1140 mirror->pg_bytes_written += mirror->pg_count;
1141 }
1142}
1143
1144static void
1145nfs_pageio_cleanup_request(struct nfs_pageio_descriptor *desc,
1146 struct nfs_page *req)
1147{
1148 LIST_HEAD(head);
1149
1150 nfs_list_move_request(req, &head);
1151 desc->pg_completion_ops->error_cleanup(&head, desc->pg_error);
1152}
1153
1154/**
1155 * __nfs_pageio_add_request - Attempt to coalesce a request into a page list.
1156 * @desc: destination io descriptor
1157 * @req: request
1158 *
1159 * This may split a request into subrequests which are all part of the
1160 * same page group. If so, it will submit @req as the last one, to ensure
1161 * the pointer to @req is still valid in case of failure.
1162 *
1163 * Returns true if the request 'req' was successfully coalesced into the
1164 * existing list of pages 'desc'.
1165 */
1166static int __nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
1167 struct nfs_page *req)
1168{
1169 struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
1170 struct nfs_page *subreq;
1171 unsigned int size, subreq_size;
1172
1173 nfs_page_group_lock(req);
1174
1175 subreq = req;
1176 subreq_size = subreq->wb_bytes;
1177 for(;;) {
1178 size = nfs_pageio_do_add_request(desc, subreq);
1179 if (size == subreq_size) {
1180 /* We successfully submitted a request */
1181 if (subreq == req)
1182 break;
1183 req->wb_pgbase += size;
1184 req->wb_bytes -= size;
1185 req->wb_offset += size;
1186 subreq_size = req->wb_bytes;
1187 subreq = req;
1188 continue;
1189 }
1190 if (WARN_ON_ONCE(subreq != req)) {
1191 nfs_page_group_unlock(req);
1192 nfs_pageio_cleanup_request(desc, subreq);
1193 subreq = req;
1194 subreq_size = req->wb_bytes;
1195 nfs_page_group_lock(req);
1196 }
1197 if (!size) {
1198 /* Can't coalesce any more, so do I/O */
1199 nfs_page_group_unlock(req);
1200 desc->pg_moreio = 1;
1201 nfs_pageio_doio(desc);
1202 if (desc->pg_error < 0 || mirror->pg_recoalesce)
1203 return 0;
1204 /* retry add_request for this subreq */
1205 nfs_page_group_lock(req);
1206 continue;
1207 }
1208 subreq = nfs_create_subreq(req, req->wb_pgbase,
1209 req->wb_offset, size);
1210 if (IS_ERR(subreq))
1211 goto err_ptr;
1212 subreq_size = size;
1213 }
1214
1215 nfs_page_group_unlock(req);
1216 return 1;
1217err_ptr:
1218 desc->pg_error = PTR_ERR(subreq);
1219 nfs_page_group_unlock(req);
1220 return 0;
1221}
1222
1223static int nfs_do_recoalesce(struct nfs_pageio_descriptor *desc)
1224{
1225 struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
1226 LIST_HEAD(head);
1227
1228 do {
1229 list_splice_init(&mirror->pg_list, &head);
1230
1231 while (!list_empty(&head)) {
1232 struct nfs_page *req;
1233
1234 req = list_first_entry(&head, struct nfs_page, wb_list);
1235 if (__nfs_pageio_add_request(desc, req))
1236 continue;
1237 if (desc->pg_error < 0) {
1238 list_splice_tail(&head, &mirror->pg_list);
1239 mirror->pg_recoalesce = 1;
1240 return 0;
1241 }
1242 break;
1243 }
1244 } while (mirror->pg_recoalesce);
1245 return 1;
1246}
1247
1248static int nfs_pageio_add_request_mirror(struct nfs_pageio_descriptor *desc,
1249 struct nfs_page *req)
1250{
1251 int ret;
1252
1253 do {
1254 ret = __nfs_pageio_add_request(desc, req);
1255 if (ret)
1256 break;
1257 if (desc->pg_error < 0)
1258 break;
1259 ret = nfs_do_recoalesce(desc);
1260 } while (ret);
1261
1262 return ret;
1263}
1264
1265static void nfs_pageio_error_cleanup(struct nfs_pageio_descriptor *desc)
1266{
1267 u32 midx;
1268 struct nfs_pgio_mirror *mirror;
1269
1270 if (!desc->pg_error)
1271 return;
1272
1273 for (midx = 0; midx < desc->pg_mirror_count; midx++) {
1274 mirror = nfs_pgio_get_mirror(desc, midx);
1275 desc->pg_completion_ops->error_cleanup(&mirror->pg_list,
1276 desc->pg_error);
1277 }
1278}
1279
1280int nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
1281 struct nfs_page *req)
1282{
1283 u32 midx;
1284 unsigned int pgbase, offset, bytes;
1285 struct nfs_page *dupreq;
1286
1287 pgbase = req->wb_pgbase;
1288 offset = req->wb_offset;
1289 bytes = req->wb_bytes;
1290
1291 nfs_pageio_setup_mirroring(desc, req);
1292 if (desc->pg_error < 0)
1293 goto out_failed;
1294
1295 /* Create the mirror instances first, and fire them off */
1296 for (midx = 1; midx < desc->pg_mirror_count; midx++) {
1297 nfs_page_group_lock(req);
1298
1299 dupreq = nfs_create_subreq(req,
1300 pgbase, offset, bytes);
1301
1302 nfs_page_group_unlock(req);
1303 if (IS_ERR(dupreq)) {
1304 desc->pg_error = PTR_ERR(dupreq);
1305 goto out_failed;
1306 }
1307
1308 nfs_pgio_set_current_mirror(desc, midx);
1309 if (!nfs_pageio_add_request_mirror(desc, dupreq))
1310 goto out_cleanup_subreq;
1311 }
1312
1313 nfs_pgio_set_current_mirror(desc, 0);
1314 if (!nfs_pageio_add_request_mirror(desc, req))
1315 goto out_failed;
1316
1317 return 1;
1318
1319out_cleanup_subreq:
1320 nfs_pageio_cleanup_request(desc, dupreq);
1321out_failed:
1322 nfs_pageio_error_cleanup(desc);
1323 return 0;
1324}
1325
1326/*
1327 * nfs_pageio_complete_mirror - Complete I/O on the current mirror of an
1328 * nfs_pageio_descriptor
1329 * @desc: pointer to io descriptor
1330 * @mirror_idx: pointer to mirror index
1331 */
1332static void nfs_pageio_complete_mirror(struct nfs_pageio_descriptor *desc,
1333 u32 mirror_idx)
1334{
1335 struct nfs_pgio_mirror *mirror;
1336 u32 restore_idx;
1337
1338 restore_idx = nfs_pgio_set_current_mirror(desc, mirror_idx);
1339 mirror = nfs_pgio_current_mirror(desc);
1340
1341 for (;;) {
1342 nfs_pageio_doio(desc);
1343 if (desc->pg_error < 0 || !mirror->pg_recoalesce)
1344 break;
1345 if (!nfs_do_recoalesce(desc))
1346 break;
1347 }
1348 nfs_pgio_set_current_mirror(desc, restore_idx);
1349}
1350
1351/*
1352 * nfs_pageio_resend - Transfer requests to new descriptor and resend
1353 * @hdr - the pgio header to move request from
1354 * @desc - the pageio descriptor to add requests to
1355 *
1356 * Try to move each request (nfs_page) from @hdr to @desc then attempt
1357 * to send them.
1358 *
1359 * Returns 0 on success and < 0 on error.
1360 */
1361int nfs_pageio_resend(struct nfs_pageio_descriptor *desc,
1362 struct nfs_pgio_header *hdr)
1363{
1364 LIST_HEAD(pages);
1365
1366 desc->pg_io_completion = hdr->io_completion;
1367 desc->pg_dreq = hdr->dreq;
1368 list_splice_init(&hdr->pages, &pages);
1369 while (!list_empty(&pages)) {
1370 struct nfs_page *req = nfs_list_entry(pages.next);
1371
1372 if (!nfs_pageio_add_request(desc, req))
1373 break;
1374 }
1375 nfs_pageio_complete(desc);
1376 if (!list_empty(&pages)) {
1377 int err = desc->pg_error < 0 ? desc->pg_error : -EIO;
1378 hdr->completion_ops->error_cleanup(&pages, err);
1379 nfs_set_pgio_error(hdr, err, hdr->io_start);
1380 return err;
1381 }
1382 return 0;
1383}
1384EXPORT_SYMBOL_GPL(nfs_pageio_resend);
1385
1386/**
1387 * nfs_pageio_complete - Complete I/O then cleanup an nfs_pageio_descriptor
1388 * @desc: pointer to io descriptor
1389 */
1390void nfs_pageio_complete(struct nfs_pageio_descriptor *desc)
1391{
1392 u32 midx;
1393
1394 for (midx = 0; midx < desc->pg_mirror_count; midx++)
1395 nfs_pageio_complete_mirror(desc, midx);
1396
1397 if (desc->pg_error < 0)
1398 nfs_pageio_error_cleanup(desc);
1399 if (desc->pg_ops->pg_cleanup)
1400 desc->pg_ops->pg_cleanup(desc);
1401 nfs_pageio_cleanup_mirroring(desc);
1402}
1403
1404/**
1405 * nfs_pageio_cond_complete - Conditional I/O completion
1406 * @desc: pointer to io descriptor
1407 * @index: page index
1408 *
1409 * It is important to ensure that processes don't try to take locks
1410 * on non-contiguous ranges of pages as that might deadlock. This
1411 * function should be called before attempting to wait on a locked
1412 * nfs_page. It will complete the I/O if the page index 'index'
1413 * is not contiguous with the existing list of pages in 'desc'.
1414 */
1415void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *desc, pgoff_t index)
1416{
1417 struct nfs_pgio_mirror *mirror;
1418 struct nfs_page *prev;
1419 u32 midx;
1420
1421 for (midx = 0; midx < desc->pg_mirror_count; midx++) {
1422 mirror = nfs_pgio_get_mirror(desc, midx);
1423 if (!list_empty(&mirror->pg_list)) {
1424 prev = nfs_list_entry(mirror->pg_list.prev);
1425 if (index != prev->wb_index + 1) {
1426 nfs_pageio_complete(desc);
1427 break;
1428 }
1429 }
1430 }
1431}
1432
1433/*
1434 * nfs_pageio_stop_mirroring - stop using mirroring (set mirror count to 1)
1435 */
1436void nfs_pageio_stop_mirroring(struct nfs_pageio_descriptor *pgio)
1437{
1438 nfs_pageio_complete(pgio);
1439}
1440
1441int __init nfs_init_nfspagecache(void)
1442{
1443 nfs_page_cachep = kmem_cache_create("nfs_page",
1444 sizeof(struct nfs_page),
1445 0, SLAB_HWCACHE_ALIGN,
1446 NULL);
1447 if (nfs_page_cachep == NULL)
1448 return -ENOMEM;
1449
1450 return 0;
1451}
1452
1453void nfs_destroy_nfspagecache(void)
1454{
1455 kmem_cache_destroy(nfs_page_cachep);
1456}
1457
1458static const struct rpc_call_ops nfs_pgio_common_ops = {
1459 .rpc_call_prepare = nfs_pgio_prepare,
1460 .rpc_call_done = nfs_pgio_result,
1461 .rpc_release = nfs_pgio_release,
1462};
1463
1464const struct nfs_pageio_ops nfs_pgio_rw_ops = {
1465 .pg_test = nfs_generic_pg_test,
1466 .pg_doio = nfs_generic_pg_pgios,
1467};