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