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