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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
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};
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 req->wb_index = page_file_index(page);
345 get_page(page);
346 req->wb_offset = offset;
347 req->wb_pgbase = offset;
348 req->wb_bytes = count;
349 req->wb_context = get_nfs_open_context(ctx);
350 kref_init(&req->wb_kref);
351 nfs_page_group_init(req, last);
352 return req;
353}
354
355/**
356 * nfs_unlock_request - Unlock request and wake up sleepers.
357 * @req:
358 */
359void nfs_unlock_request(struct nfs_page *req)
360{
361 if (!NFS_WBACK_BUSY(req)) {
362 printk(KERN_ERR "NFS: Invalid unlock attempted\n");
363 BUG();
364 }
365 smp_mb__before_atomic();
366 clear_bit(PG_BUSY, &req->wb_flags);
367 smp_mb__after_atomic();
368 wake_up_bit(&req->wb_flags, PG_BUSY);
369}
370
371/**
372 * nfs_unlock_and_release_request - Unlock request and release the nfs_page
373 * @req:
374 */
375void nfs_unlock_and_release_request(struct nfs_page *req)
376{
377 nfs_unlock_request(req);
378 nfs_release_request(req);
379}
380
381/*
382 * nfs_clear_request - Free up all resources allocated to the request
383 * @req:
384 *
385 * Release page and open context resources associated with a read/write
386 * request after it has completed.
387 */
388static void nfs_clear_request(struct nfs_page *req)
389{
390 struct page *page = req->wb_page;
391 struct nfs_open_context *ctx = req->wb_context;
392 struct nfs_lock_context *l_ctx = req->wb_lock_context;
393
394 if (page != NULL) {
395 put_page(page);
396 req->wb_page = NULL;
397 }
398 if (l_ctx != NULL) {
399 if (atomic_dec_and_test(&l_ctx->io_count))
400 wake_up_atomic_t(&l_ctx->io_count);
401 nfs_put_lock_context(l_ctx);
402 req->wb_lock_context = NULL;
403 }
404 if (ctx != NULL) {
405 put_nfs_open_context(ctx);
406 req->wb_context = NULL;
407 }
408}
409
410/**
411 * nfs_release_request - Release the count on an NFS read/write request
412 * @req: request to release
413 *
414 * Note: Should never be called with the spinlock held!
415 */
416void nfs_free_request(struct nfs_page *req)
417{
418 WARN_ON_ONCE(req->wb_this_page != req);
419
420 /* extra debug: make sure no sync bits are still set */
421 WARN_ON_ONCE(test_bit(PG_TEARDOWN, &req->wb_flags));
422 WARN_ON_ONCE(test_bit(PG_UNLOCKPAGE, &req->wb_flags));
423 WARN_ON_ONCE(test_bit(PG_UPTODATE, &req->wb_flags));
424 WARN_ON_ONCE(test_bit(PG_WB_END, &req->wb_flags));
425 WARN_ON_ONCE(test_bit(PG_REMOVE, &req->wb_flags));
426
427 /* Release struct file and open context */
428 nfs_clear_request(req);
429 nfs_page_free(req);
430}
431
432void nfs_release_request(struct nfs_page *req)
433{
434 kref_put(&req->wb_kref, nfs_page_group_destroy);
435}
436
437/**
438 * nfs_wait_on_request - Wait for a request to complete.
439 * @req: request to wait upon.
440 *
441 * Interruptible by fatal signals only.
442 * The user is responsible for holding a count on the request.
443 */
444int
445nfs_wait_on_request(struct nfs_page *req)
446{
447 return wait_on_bit_io(&req->wb_flags, PG_BUSY,
448 TASK_UNINTERRUPTIBLE);
449}
450
451/*
452 * nfs_generic_pg_test - determine if requests can be coalesced
453 * @desc: pointer to descriptor
454 * @prev: previous request in desc, or NULL
455 * @req: this request
456 *
457 * Returns zero if @req can be coalesced into @desc, otherwise it returns
458 * the size of the request.
459 */
460size_t nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
461 struct nfs_page *prev, struct nfs_page *req)
462{
463 struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
464
465
466 if (mirror->pg_count > mirror->pg_bsize) {
467 /* should never happen */
468 WARN_ON_ONCE(1);
469 return 0;
470 }
471
472 /*
473 * Limit the request size so that we can still allocate a page array
474 * for it without upsetting the slab allocator.
475 */
476 if (((mirror->pg_count + req->wb_bytes) >> PAGE_SHIFT) *
477 sizeof(struct page *) > PAGE_SIZE)
478 return 0;
479
480 return min(mirror->pg_bsize - mirror->pg_count, (size_t)req->wb_bytes);
481}
482EXPORT_SYMBOL_GPL(nfs_generic_pg_test);
483
484struct nfs_pgio_header *nfs_pgio_header_alloc(const struct nfs_rw_ops *ops)
485{
486 struct nfs_pgio_header *hdr = ops->rw_alloc_header();
487
488 if (hdr) {
489 INIT_LIST_HEAD(&hdr->pages);
490 spin_lock_init(&hdr->lock);
491 hdr->rw_ops = ops;
492 }
493 return hdr;
494}
495EXPORT_SYMBOL_GPL(nfs_pgio_header_alloc);
496
497/*
498 * nfs_pgio_header_free - Free a read or write header
499 * @hdr: The header to free
500 */
501void nfs_pgio_header_free(struct nfs_pgio_header *hdr)
502{
503 hdr->rw_ops->rw_free_header(hdr);
504}
505EXPORT_SYMBOL_GPL(nfs_pgio_header_free);
506
507/**
508 * nfs_pgio_data_destroy - make @hdr suitable for reuse
509 *
510 * Frees memory and releases refs from nfs_generic_pgio, so that it may
511 * be called again.
512 *
513 * @hdr: A header that has had nfs_generic_pgio called
514 */
515void nfs_pgio_data_destroy(struct nfs_pgio_header *hdr)
516{
517 if (hdr->args.context)
518 put_nfs_open_context(hdr->args.context);
519 if (hdr->page_array.pagevec != hdr->page_array.page_array)
520 kfree(hdr->page_array.pagevec);
521}
522EXPORT_SYMBOL_GPL(nfs_pgio_data_destroy);
523
524/**
525 * nfs_pgio_rpcsetup - Set up arguments for a pageio call
526 * @hdr: The pageio hdr
527 * @count: Number of bytes to read
528 * @offset: Initial offset
529 * @how: How to commit data (writes only)
530 * @cinfo: Commit information for the call (writes only)
531 */
532static void nfs_pgio_rpcsetup(struct nfs_pgio_header *hdr,
533 unsigned int count, unsigned int offset,
534 int how, struct nfs_commit_info *cinfo)
535{
536 struct nfs_page *req = hdr->req;
537
538 /* Set up the RPC argument and reply structs
539 * NB: take care not to mess about with hdr->commit et al. */
540
541 hdr->args.fh = NFS_FH(hdr->inode);
542 hdr->args.offset = req_offset(req) + offset;
543 /* pnfs_set_layoutcommit needs this */
544 hdr->mds_offset = hdr->args.offset;
545 hdr->args.pgbase = req->wb_pgbase + offset;
546 hdr->args.pages = hdr->page_array.pagevec;
547 hdr->args.count = count;
548 hdr->args.context = get_nfs_open_context(req->wb_context);
549 hdr->args.lock_context = req->wb_lock_context;
550 hdr->args.stable = NFS_UNSTABLE;
551 switch (how & (FLUSH_STABLE | FLUSH_COND_STABLE)) {
552 case 0:
553 break;
554 case FLUSH_COND_STABLE:
555 if (nfs_reqs_to_commit(cinfo))
556 break;
557 default:
558 hdr->args.stable = NFS_FILE_SYNC;
559 }
560
561 hdr->res.fattr = &hdr->fattr;
562 hdr->res.count = count;
563 hdr->res.eof = 0;
564 hdr->res.verf = &hdr->verf;
565 nfs_fattr_init(&hdr->fattr);
566}
567
568/**
569 * nfs_pgio_prepare - Prepare pageio hdr to go over the wire
570 * @task: The current task
571 * @calldata: pageio header to prepare
572 */
573static void nfs_pgio_prepare(struct rpc_task *task, void *calldata)
574{
575 struct nfs_pgio_header *hdr = calldata;
576 int err;
577 err = NFS_PROTO(hdr->inode)->pgio_rpc_prepare(task, hdr);
578 if (err)
579 rpc_exit(task, err);
580}
581
582int nfs_initiate_pgio(struct rpc_clnt *clnt, struct nfs_pgio_header *hdr,
583 struct rpc_cred *cred, const struct nfs_rpc_ops *rpc_ops,
584 const struct rpc_call_ops *call_ops, int how, int flags)
585{
586 struct rpc_task *task;
587 struct rpc_message msg = {
588 .rpc_argp = &hdr->args,
589 .rpc_resp = &hdr->res,
590 .rpc_cred = cred,
591 };
592 struct rpc_task_setup task_setup_data = {
593 .rpc_client = clnt,
594 .task = &hdr->task,
595 .rpc_message = &msg,
596 .callback_ops = call_ops,
597 .callback_data = hdr,
598 .workqueue = nfsiod_workqueue,
599 .flags = RPC_TASK_ASYNC | flags,
600 };
601 int ret = 0;
602
603 hdr->rw_ops->rw_initiate(hdr, &msg, rpc_ops, &task_setup_data, how);
604
605 dprintk("NFS: initiated pgio call "
606 "(req %s/%llu, %u bytes @ offset %llu)\n",
607 hdr->inode->i_sb->s_id,
608 (unsigned long long)NFS_FILEID(hdr->inode),
609 hdr->args.count,
610 (unsigned long long)hdr->args.offset);
611
612 task = rpc_run_task(&task_setup_data);
613 if (IS_ERR(task)) {
614 ret = PTR_ERR(task);
615 goto out;
616 }
617 if (how & FLUSH_SYNC) {
618 ret = rpc_wait_for_completion_task(task);
619 if (ret == 0)
620 ret = task->tk_status;
621 }
622 rpc_put_task(task);
623out:
624 return ret;
625}
626EXPORT_SYMBOL_GPL(nfs_initiate_pgio);
627
628/**
629 * nfs_pgio_error - Clean up from a pageio error
630 * @desc: IO descriptor
631 * @hdr: pageio header
632 */
633static void nfs_pgio_error(struct nfs_pgio_header *hdr)
634{
635 set_bit(NFS_IOHDR_REDO, &hdr->flags);
636 nfs_pgio_data_destroy(hdr);
637 hdr->completion_ops->completion(hdr);
638}
639
640/**
641 * nfs_pgio_release - Release pageio data
642 * @calldata: The pageio header to release
643 */
644static void nfs_pgio_release(void *calldata)
645{
646 struct nfs_pgio_header *hdr = calldata;
647 nfs_pgio_data_destroy(hdr);
648 hdr->completion_ops->completion(hdr);
649}
650
651static void nfs_pageio_mirror_init(struct nfs_pgio_mirror *mirror,
652 unsigned int bsize)
653{
654 INIT_LIST_HEAD(&mirror->pg_list);
655 mirror->pg_bytes_written = 0;
656 mirror->pg_count = 0;
657 mirror->pg_bsize = bsize;
658 mirror->pg_base = 0;
659 mirror->pg_recoalesce = 0;
660}
661
662/**
663 * nfs_pageio_init - initialise a page io descriptor
664 * @desc: pointer to descriptor
665 * @inode: pointer to inode
666 * @pg_ops: pointer to pageio operations
667 * @compl_ops: pointer to pageio completion operations
668 * @rw_ops: pointer to nfs read/write operations
669 * @bsize: io block size
670 * @io_flags: extra parameters for the io function
671 */
672void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
673 struct inode *inode,
674 const struct nfs_pageio_ops *pg_ops,
675 const struct nfs_pgio_completion_ops *compl_ops,
676 const struct nfs_rw_ops *rw_ops,
677 size_t bsize,
678 int io_flags)
679{
680 struct nfs_pgio_mirror *new;
681 int i;
682
683 desc->pg_moreio = 0;
684 desc->pg_inode = inode;
685 desc->pg_ops = pg_ops;
686 desc->pg_completion_ops = compl_ops;
687 desc->pg_rw_ops = rw_ops;
688 desc->pg_ioflags = io_flags;
689 desc->pg_error = 0;
690 desc->pg_lseg = NULL;
691 desc->pg_dreq = NULL;
692 desc->pg_layout_private = NULL;
693 desc->pg_bsize = bsize;
694
695 desc->pg_mirror_count = 1;
696 desc->pg_mirror_idx = 0;
697
698 if (pg_ops->pg_get_mirror_count) {
699 /* until we have a request, we don't have an lseg and no
700 * idea how many mirrors there will be */
701 new = kcalloc(NFS_PAGEIO_DESCRIPTOR_MIRROR_MAX,
702 sizeof(struct nfs_pgio_mirror), GFP_KERNEL);
703 desc->pg_mirrors_dynamic = new;
704 desc->pg_mirrors = new;
705
706 for (i = 0; i < NFS_PAGEIO_DESCRIPTOR_MIRROR_MAX; i++)
707 nfs_pageio_mirror_init(&desc->pg_mirrors[i], bsize);
708 } else {
709 desc->pg_mirrors_dynamic = NULL;
710 desc->pg_mirrors = desc->pg_mirrors_static;
711 nfs_pageio_mirror_init(&desc->pg_mirrors[0], bsize);
712 }
713}
714EXPORT_SYMBOL_GPL(nfs_pageio_init);
715
716/**
717 * nfs_pgio_result - Basic pageio error handling
718 * @task: The task that ran
719 * @calldata: Pageio header to check
720 */
721static void nfs_pgio_result(struct rpc_task *task, void *calldata)
722{
723 struct nfs_pgio_header *hdr = calldata;
724 struct inode *inode = hdr->inode;
725
726 dprintk("NFS: %s: %5u, (status %d)\n", __func__,
727 task->tk_pid, task->tk_status);
728
729 if (hdr->rw_ops->rw_done(task, hdr, inode) != 0)
730 return;
731 if (task->tk_status < 0)
732 nfs_set_pgio_error(hdr, task->tk_status, hdr->args.offset);
733 else
734 hdr->rw_ops->rw_result(task, hdr);
735}
736
737/*
738 * Create an RPC task for the given read or write request and kick it.
739 * The page must have been locked by the caller.
740 *
741 * It may happen that the page we're passed is not marked dirty.
742 * This is the case if nfs_updatepage detects a conflicting request
743 * that has been written but not committed.
744 */
745int nfs_generic_pgio(struct nfs_pageio_descriptor *desc,
746 struct nfs_pgio_header *hdr)
747{
748 struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
749
750 struct nfs_page *req;
751 struct page **pages,
752 *last_page;
753 struct list_head *head = &mirror->pg_list;
754 struct nfs_commit_info cinfo;
755 unsigned int pagecount, pageused;
756
757 pagecount = nfs_page_array_len(mirror->pg_base, mirror->pg_count);
758 if (!nfs_pgarray_set(&hdr->page_array, pagecount)) {
759 nfs_pgio_error(hdr);
760 desc->pg_error = -ENOMEM;
761 return desc->pg_error;
762 }
763
764 nfs_init_cinfo(&cinfo, desc->pg_inode, desc->pg_dreq);
765 pages = hdr->page_array.pagevec;
766 last_page = NULL;
767 pageused = 0;
768 while (!list_empty(head)) {
769 req = nfs_list_entry(head->next);
770 nfs_list_remove_request(req);
771 nfs_list_add_request(req, &hdr->pages);
772
773 if (!last_page || last_page != req->wb_page) {
774 pageused++;
775 if (pageused > pagecount)
776 break;
777 *pages++ = last_page = req->wb_page;
778 }
779 }
780 if (WARN_ON_ONCE(pageused != pagecount)) {
781 nfs_pgio_error(hdr);
782 desc->pg_error = -EINVAL;
783 return desc->pg_error;
784 }
785
786 if ((desc->pg_ioflags & FLUSH_COND_STABLE) &&
787 (desc->pg_moreio || nfs_reqs_to_commit(&cinfo)))
788 desc->pg_ioflags &= ~FLUSH_COND_STABLE;
789
790 /* Set up the argument struct */
791 nfs_pgio_rpcsetup(hdr, mirror->pg_count, 0, desc->pg_ioflags, &cinfo);
792 desc->pg_rpc_callops = &nfs_pgio_common_ops;
793 return 0;
794}
795EXPORT_SYMBOL_GPL(nfs_generic_pgio);
796
797static int nfs_generic_pg_pgios(struct nfs_pageio_descriptor *desc)
798{
799 struct nfs_pgio_header *hdr;
800 int ret;
801
802 hdr = nfs_pgio_header_alloc(desc->pg_rw_ops);
803 if (!hdr) {
804 desc->pg_error = -ENOMEM;
805 return desc->pg_error;
806 }
807 nfs_pgheader_init(desc, hdr, nfs_pgio_header_free);
808 ret = nfs_generic_pgio(desc, hdr);
809 if (ret == 0)
810 ret = nfs_initiate_pgio(NFS_CLIENT(hdr->inode),
811 hdr,
812 hdr->cred,
813 NFS_PROTO(hdr->inode),
814 desc->pg_rpc_callops,
815 desc->pg_ioflags, 0);
816 return ret;
817}
818
819/*
820 * nfs_pageio_setup_mirroring - determine if mirroring is to be used
821 * by calling the pg_get_mirror_count op
822 */
823static int nfs_pageio_setup_mirroring(struct nfs_pageio_descriptor *pgio,
824 struct nfs_page *req)
825{
826 int mirror_count = 1;
827
828 if (!pgio->pg_ops->pg_get_mirror_count)
829 return 0;
830
831 mirror_count = pgio->pg_ops->pg_get_mirror_count(pgio, req);
832
833 if (pgio->pg_error < 0)
834 return pgio->pg_error;
835
836 if (!mirror_count || mirror_count > NFS_PAGEIO_DESCRIPTOR_MIRROR_MAX)
837 return -EINVAL;
838
839 if (WARN_ON_ONCE(!pgio->pg_mirrors_dynamic))
840 return -EINVAL;
841
842 pgio->pg_mirror_count = mirror_count;
843
844 return 0;
845}
846
847/*
848 * nfs_pageio_stop_mirroring - stop using mirroring (set mirror count to 1)
849 */
850void nfs_pageio_stop_mirroring(struct nfs_pageio_descriptor *pgio)
851{
852 pgio->pg_mirror_count = 1;
853 pgio->pg_mirror_idx = 0;
854}
855
856static void nfs_pageio_cleanup_mirroring(struct nfs_pageio_descriptor *pgio)
857{
858 pgio->pg_mirror_count = 1;
859 pgio->pg_mirror_idx = 0;
860 pgio->pg_mirrors = pgio->pg_mirrors_static;
861 kfree(pgio->pg_mirrors_dynamic);
862 pgio->pg_mirrors_dynamic = NULL;
863}
864
865static bool nfs_match_lock_context(const struct nfs_lock_context *l1,
866 const struct nfs_lock_context *l2)
867{
868 return l1->lockowner.l_owner == l2->lockowner.l_owner
869 && l1->lockowner.l_pid == l2->lockowner.l_pid;
870}
871
872/**
873 * nfs_can_coalesce_requests - test two requests for compatibility
874 * @prev: pointer to nfs_page
875 * @req: pointer to nfs_page
876 *
877 * The nfs_page structures 'prev' and 'req' are compared to ensure that the
878 * page data area they describe is contiguous, and that their RPC
879 * credentials, NFSv4 open state, and lockowners are the same.
880 *
881 * Return 'true' if this is the case, else return 'false'.
882 */
883static bool nfs_can_coalesce_requests(struct nfs_page *prev,
884 struct nfs_page *req,
885 struct nfs_pageio_descriptor *pgio)
886{
887 size_t size;
888 struct file_lock_context *flctx;
889
890 if (prev) {
891 if (!nfs_match_open_context(req->wb_context, prev->wb_context))
892 return false;
893 flctx = d_inode(req->wb_context->dentry)->i_flctx;
894 if (flctx != NULL &&
895 !(list_empty_careful(&flctx->flc_posix) &&
896 list_empty_careful(&flctx->flc_flock)) &&
897 !nfs_match_lock_context(req->wb_lock_context,
898 prev->wb_lock_context))
899 return false;
900 if (req_offset(req) != req_offset(prev) + prev->wb_bytes)
901 return false;
902 if (req->wb_page == prev->wb_page) {
903 if (req->wb_pgbase != prev->wb_pgbase + prev->wb_bytes)
904 return false;
905 } else {
906 if (req->wb_pgbase != 0 ||
907 prev->wb_pgbase + prev->wb_bytes != PAGE_SIZE)
908 return false;
909 }
910 }
911 size = pgio->pg_ops->pg_test(pgio, prev, req);
912 WARN_ON_ONCE(size > req->wb_bytes);
913 if (size && size < req->wb_bytes)
914 req->wb_bytes = size;
915 return size > 0;
916}
917
918/**
919 * nfs_pageio_do_add_request - Attempt to coalesce a request into a page list.
920 * @desc: destination io descriptor
921 * @req: request
922 *
923 * Returns true if the request 'req' was successfully coalesced into the
924 * existing list of pages 'desc'.
925 */
926static int nfs_pageio_do_add_request(struct nfs_pageio_descriptor *desc,
927 struct nfs_page *req)
928{
929 struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
930
931 struct nfs_page *prev = NULL;
932
933 if (mirror->pg_count != 0) {
934 prev = nfs_list_entry(mirror->pg_list.prev);
935 } else {
936 if (desc->pg_ops->pg_init)
937 desc->pg_ops->pg_init(desc, req);
938 if (desc->pg_error < 0)
939 return 0;
940 mirror->pg_base = req->wb_pgbase;
941 }
942 if (!nfs_can_coalesce_requests(prev, req, desc))
943 return 0;
944 nfs_list_remove_request(req);
945 nfs_list_add_request(req, &mirror->pg_list);
946 mirror->pg_count += req->wb_bytes;
947 return 1;
948}
949
950/*
951 * Helper for nfs_pageio_add_request and nfs_pageio_complete
952 */
953static void nfs_pageio_doio(struct nfs_pageio_descriptor *desc)
954{
955 struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
956
957
958 if (!list_empty(&mirror->pg_list)) {
959 int error = desc->pg_ops->pg_doio(desc);
960 if (error < 0)
961 desc->pg_error = error;
962 else
963 mirror->pg_bytes_written += mirror->pg_count;
964 }
965 if (list_empty(&mirror->pg_list)) {
966 mirror->pg_count = 0;
967 mirror->pg_base = 0;
968 }
969}
970
971/**
972 * nfs_pageio_add_request - Attempt to coalesce a request into a page list.
973 * @desc: destination io descriptor
974 * @req: request
975 *
976 * This may split a request into subrequests which are all part of the
977 * same page group.
978 *
979 * Returns true if the request 'req' was successfully coalesced into the
980 * existing list of pages 'desc'.
981 */
982static int __nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
983 struct nfs_page *req)
984{
985 struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
986
987 struct nfs_page *subreq;
988 unsigned int bytes_left = 0;
989 unsigned int offset, pgbase;
990
991 nfs_page_group_lock(req, false);
992
993 subreq = req;
994 bytes_left = subreq->wb_bytes;
995 offset = subreq->wb_offset;
996 pgbase = subreq->wb_pgbase;
997
998 do {
999 if (!nfs_pageio_do_add_request(desc, subreq)) {
1000 /* make sure pg_test call(s) did nothing */
1001 WARN_ON_ONCE(subreq->wb_bytes != bytes_left);
1002 WARN_ON_ONCE(subreq->wb_offset != offset);
1003 WARN_ON_ONCE(subreq->wb_pgbase != pgbase);
1004
1005 nfs_page_group_unlock(req);
1006 desc->pg_moreio = 1;
1007 nfs_pageio_doio(desc);
1008 if (desc->pg_error < 0)
1009 return 0;
1010 if (mirror->pg_recoalesce)
1011 return 0;
1012 /* retry add_request for this subreq */
1013 nfs_page_group_lock(req, false);
1014 continue;
1015 }
1016
1017 /* check for buggy pg_test call(s) */
1018 WARN_ON_ONCE(subreq->wb_bytes + subreq->wb_pgbase > PAGE_SIZE);
1019 WARN_ON_ONCE(subreq->wb_bytes > bytes_left);
1020 WARN_ON_ONCE(subreq->wb_bytes == 0);
1021
1022 bytes_left -= subreq->wb_bytes;
1023 offset += subreq->wb_bytes;
1024 pgbase += subreq->wb_bytes;
1025
1026 if (bytes_left) {
1027 subreq = nfs_create_request(req->wb_context,
1028 req->wb_page,
1029 subreq, pgbase, bytes_left);
1030 if (IS_ERR(subreq))
1031 goto err_ptr;
1032 nfs_lock_request(subreq);
1033 subreq->wb_offset = offset;
1034 subreq->wb_index = req->wb_index;
1035 }
1036 } while (bytes_left > 0);
1037
1038 nfs_page_group_unlock(req);
1039 return 1;
1040err_ptr:
1041 desc->pg_error = PTR_ERR(subreq);
1042 nfs_page_group_unlock(req);
1043 return 0;
1044}
1045
1046static int nfs_do_recoalesce(struct nfs_pageio_descriptor *desc)
1047{
1048 struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
1049 LIST_HEAD(head);
1050
1051 do {
1052 list_splice_init(&mirror->pg_list, &head);
1053 mirror->pg_bytes_written -= mirror->pg_count;
1054 mirror->pg_count = 0;
1055 mirror->pg_base = 0;
1056 mirror->pg_recoalesce = 0;
1057
1058 while (!list_empty(&head)) {
1059 struct nfs_page *req;
1060
1061 req = list_first_entry(&head, struct nfs_page, wb_list);
1062 nfs_list_remove_request(req);
1063 if (__nfs_pageio_add_request(desc, req))
1064 continue;
1065 if (desc->pg_error < 0) {
1066 list_splice_tail(&head, &mirror->pg_list);
1067 mirror->pg_recoalesce = 1;
1068 return 0;
1069 }
1070 break;
1071 }
1072 } while (mirror->pg_recoalesce);
1073 return 1;
1074}
1075
1076static int nfs_pageio_add_request_mirror(struct nfs_pageio_descriptor *desc,
1077 struct nfs_page *req)
1078{
1079 int ret;
1080
1081 do {
1082 ret = __nfs_pageio_add_request(desc, req);
1083 if (ret)
1084 break;
1085 if (desc->pg_error < 0)
1086 break;
1087 ret = nfs_do_recoalesce(desc);
1088 } while (ret);
1089
1090 return ret;
1091}
1092
1093int nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
1094 struct nfs_page *req)
1095{
1096 u32 midx;
1097 unsigned int pgbase, offset, bytes;
1098 struct nfs_page *dupreq, *lastreq;
1099
1100 pgbase = req->wb_pgbase;
1101 offset = req->wb_offset;
1102 bytes = req->wb_bytes;
1103
1104 nfs_pageio_setup_mirroring(desc, req);
1105 if (desc->pg_error < 0)
1106 goto out_failed;
1107
1108 for (midx = 0; midx < desc->pg_mirror_count; midx++) {
1109 if (midx) {
1110 nfs_page_group_lock(req, false);
1111
1112 /* find the last request */
1113 for (lastreq = req->wb_head;
1114 lastreq->wb_this_page != req->wb_head;
1115 lastreq = lastreq->wb_this_page)
1116 ;
1117
1118 dupreq = nfs_create_request(req->wb_context,
1119 req->wb_page, lastreq, pgbase, bytes);
1120
1121 if (IS_ERR(dupreq)) {
1122 nfs_page_group_unlock(req);
1123 desc->pg_error = PTR_ERR(dupreq);
1124 goto out_failed;
1125 }
1126
1127 nfs_lock_request(dupreq);
1128 nfs_page_group_unlock(req);
1129 dupreq->wb_offset = offset;
1130 dupreq->wb_index = req->wb_index;
1131 } else
1132 dupreq = req;
1133
1134 if (nfs_pgio_has_mirroring(desc))
1135 desc->pg_mirror_idx = midx;
1136 if (!nfs_pageio_add_request_mirror(desc, dupreq))
1137 goto out_failed;
1138 }
1139
1140 return 1;
1141
1142out_failed:
1143 /*
1144 * We might have failed before sending any reqs over wire.
1145 * Clean up rest of the reqs in mirror pg_list.
1146 */
1147 if (desc->pg_error) {
1148 struct nfs_pgio_mirror *mirror;
1149 void (*func)(struct list_head *);
1150
1151 /* remember fatal errors */
1152 if (nfs_error_is_fatal(desc->pg_error))
1153 mapping_set_error(desc->pg_inode->i_mapping,
1154 desc->pg_error);
1155
1156 func = desc->pg_completion_ops->error_cleanup;
1157 for (midx = 0; midx < desc->pg_mirror_count; midx++) {
1158 mirror = &desc->pg_mirrors[midx];
1159 func(&mirror->pg_list);
1160 }
1161 }
1162 return 0;
1163}
1164
1165/*
1166 * nfs_pageio_complete_mirror - Complete I/O on the current mirror of an
1167 * nfs_pageio_descriptor
1168 * @desc: pointer to io descriptor
1169 * @mirror_idx: pointer to mirror index
1170 */
1171static void nfs_pageio_complete_mirror(struct nfs_pageio_descriptor *desc,
1172 u32 mirror_idx)
1173{
1174 struct nfs_pgio_mirror *mirror = &desc->pg_mirrors[mirror_idx];
1175 u32 restore_idx = desc->pg_mirror_idx;
1176
1177 if (nfs_pgio_has_mirroring(desc))
1178 desc->pg_mirror_idx = mirror_idx;
1179 for (;;) {
1180 nfs_pageio_doio(desc);
1181 if (!mirror->pg_recoalesce)
1182 break;
1183 if (!nfs_do_recoalesce(desc))
1184 break;
1185 }
1186 desc->pg_mirror_idx = restore_idx;
1187}
1188
1189/*
1190 * nfs_pageio_resend - Transfer requests to new descriptor and resend
1191 * @hdr - the pgio header to move request from
1192 * @desc - the pageio descriptor to add requests to
1193 *
1194 * Try to move each request (nfs_page) from @hdr to @desc then attempt
1195 * to send them.
1196 *
1197 * Returns 0 on success and < 0 on error.
1198 */
1199int nfs_pageio_resend(struct nfs_pageio_descriptor *desc,
1200 struct nfs_pgio_header *hdr)
1201{
1202 LIST_HEAD(failed);
1203
1204 desc->pg_dreq = hdr->dreq;
1205 while (!list_empty(&hdr->pages)) {
1206 struct nfs_page *req = nfs_list_entry(hdr->pages.next);
1207
1208 nfs_list_remove_request(req);
1209 if (!nfs_pageio_add_request(desc, req))
1210 nfs_list_add_request(req, &failed);
1211 }
1212 nfs_pageio_complete(desc);
1213 if (!list_empty(&failed)) {
1214 list_move(&failed, &hdr->pages);
1215 return desc->pg_error < 0 ? desc->pg_error : -EIO;
1216 }
1217 return 0;
1218}
1219EXPORT_SYMBOL_GPL(nfs_pageio_resend);
1220
1221/**
1222 * nfs_pageio_complete - Complete I/O then cleanup an nfs_pageio_descriptor
1223 * @desc: pointer to io descriptor
1224 */
1225void nfs_pageio_complete(struct nfs_pageio_descriptor *desc)
1226{
1227 u32 midx;
1228
1229 for (midx = 0; midx < desc->pg_mirror_count; midx++)
1230 nfs_pageio_complete_mirror(desc, midx);
1231
1232 if (desc->pg_ops->pg_cleanup)
1233 desc->pg_ops->pg_cleanup(desc);
1234 nfs_pageio_cleanup_mirroring(desc);
1235}
1236
1237/**
1238 * nfs_pageio_cond_complete - Conditional I/O completion
1239 * @desc: pointer to io descriptor
1240 * @index: page index
1241 *
1242 * It is important to ensure that processes don't try to take locks
1243 * on non-contiguous ranges of pages as that might deadlock. This
1244 * function should be called before attempting to wait on a locked
1245 * nfs_page. It will complete the I/O if the page index 'index'
1246 * is not contiguous with the existing list of pages in 'desc'.
1247 */
1248void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *desc, pgoff_t index)
1249{
1250 struct nfs_pgio_mirror *mirror;
1251 struct nfs_page *prev;
1252 u32 midx;
1253
1254 for (midx = 0; midx < desc->pg_mirror_count; midx++) {
1255 mirror = &desc->pg_mirrors[midx];
1256 if (!list_empty(&mirror->pg_list)) {
1257 prev = nfs_list_entry(mirror->pg_list.prev);
1258 if (index != prev->wb_index + 1)
1259 nfs_pageio_complete_mirror(desc, midx);
1260 }
1261 }
1262}
1263
1264int __init nfs_init_nfspagecache(void)
1265{
1266 nfs_page_cachep = kmem_cache_create("nfs_page",
1267 sizeof(struct nfs_page),
1268 0, SLAB_HWCACHE_ALIGN,
1269 NULL);
1270 if (nfs_page_cachep == NULL)
1271 return -ENOMEM;
1272
1273 return 0;
1274}
1275
1276void nfs_destroy_nfspagecache(void)
1277{
1278 kmem_cache_destroy(nfs_page_cachep);
1279}
1280
1281static const struct rpc_call_ops nfs_pgio_common_ops = {
1282 .rpc_call_prepare = nfs_pgio_prepare,
1283 .rpc_call_done = nfs_pgio_result,
1284 .rpc_release = nfs_pgio_release,
1285};
1286
1287const struct nfs_pageio_ops nfs_pgio_rw_ops = {
1288 .pg_test = nfs_generic_pg_test,
1289 .pg_doio = nfs_generic_pg_pgios,
1290};