6 * Partial copy of Linus' read cache modifications to fs/nfs/file.c
7 * modified for async RPC by okir@monad.swb.de
10 #include <linux/time.h>
11 #include <linux/kernel.h>
12 #include <linux/errno.h>
13 #include <linux/fcntl.h>
14 #include <linux/stat.h>
16 #include <linux/slab.h>
17 #include <linux/pagemap.h>
18 #include <linux/sunrpc/clnt.h>
19 #include <linux/nfs_fs.h>
20 #include <linux/nfs_page.h>
21 #include <linux/module.h>
30 #define NFSDBG_FACILITY NFSDBG_PAGECACHE
32 static const struct nfs_pageio_ops nfs_pageio_read_ops;
33 static const struct rpc_call_ops nfs_read_partial_ops;
34 static const struct rpc_call_ops nfs_read_full_ops;
36 static struct kmem_cache *nfs_rdata_cachep;
38 struct nfs_read_data *nfs_readdata_alloc(unsigned int pagecount)
40 struct nfs_read_data *p;
42 p = kmem_cache_zalloc(nfs_rdata_cachep, GFP_KERNEL);
44 INIT_LIST_HEAD(&p->pages);
45 p->npages = pagecount;
46 if (pagecount <= ARRAY_SIZE(p->page_array))
47 p->pagevec = p->page_array;
49 p->pagevec = kcalloc(pagecount, sizeof(struct page *), GFP_KERNEL);
51 kmem_cache_free(nfs_rdata_cachep, p);
59 void nfs_readdata_free(struct nfs_read_data *p)
61 if (p && (p->pagevec != &p->page_array[0]))
63 kmem_cache_free(nfs_rdata_cachep, p);
66 void nfs_readdata_release(struct nfs_read_data *rdata)
68 put_nfs_open_context(rdata->args.context);
69 nfs_readdata_free(rdata);
73 int nfs_return_empty_page(struct page *page)
75 zero_user(page, 0, PAGE_CACHE_SIZE);
76 SetPageUptodate(page);
81 static void nfs_readpage_truncate_uninitialised_page(struct nfs_read_data *data)
83 unsigned int remainder = data->args.count - data->res.count;
84 unsigned int base = data->args.pgbase + data->res.count;
88 if (data->res.eof == 0 || remainder == 0)
91 * Note: "remainder" can never be negative, since we check for
92 * this in the XDR code.
94 pages = &data->args.pages[base >> PAGE_CACHE_SHIFT];
95 base &= ~PAGE_CACHE_MASK;
96 pglen = PAGE_CACHE_SIZE - base;
98 if (remainder <= pglen) {
99 zero_user(*pages, base, remainder);
102 zero_user(*pages, base, pglen);
105 pglen = PAGE_CACHE_SIZE;
110 void nfs_pageio_init_read_mds(struct nfs_pageio_descriptor *pgio,
113 nfs_pageio_init(pgio, inode, &nfs_pageio_read_ops,
114 NFS_SERVER(inode)->rsize, 0);
117 void nfs_pageio_reset_read_mds(struct nfs_pageio_descriptor *pgio)
119 pgio->pg_ops = &nfs_pageio_read_ops;
120 pgio->pg_bsize = NFS_SERVER(pgio->pg_inode)->rsize;
122 EXPORT_SYMBOL_GPL(nfs_pageio_reset_read_mds);
124 static void nfs_pageio_init_read(struct nfs_pageio_descriptor *pgio,
127 if (!pnfs_pageio_init_read(pgio, inode))
128 nfs_pageio_init_read_mds(pgio, inode);
131 int nfs_readpage_async(struct nfs_open_context *ctx, struct inode *inode,
134 struct nfs_page *new;
136 struct nfs_pageio_descriptor pgio;
138 len = nfs_page_length(page);
140 return nfs_return_empty_page(page);
141 new = nfs_create_request(ctx, inode, page, 0, len);
146 if (len < PAGE_CACHE_SIZE)
147 zero_user_segment(page, len, PAGE_CACHE_SIZE);
149 nfs_pageio_init_read(&pgio, inode);
150 nfs_pageio_add_request(&pgio, new);
151 nfs_pageio_complete(&pgio);
155 static void nfs_readpage_release(struct nfs_page *req)
157 struct inode *d_inode = req->wb_context->dentry->d_inode;
159 if (PageUptodate(req->wb_page))
160 nfs_readpage_to_fscache(d_inode, req->wb_page, 0);
162 unlock_page(req->wb_page);
164 dprintk("NFS: read done (%s/%Ld %d@%Ld)\n",
165 req->wb_context->dentry->d_inode->i_sb->s_id,
166 (long long)NFS_FILEID(req->wb_context->dentry->d_inode),
168 (long long)req_offset(req));
169 nfs_release_request(req);
172 int nfs_initiate_read(struct nfs_read_data *data, struct rpc_clnt *clnt,
173 const struct rpc_call_ops *call_ops)
175 struct inode *inode = data->inode;
176 int swap_flags = IS_SWAPFILE(inode) ? NFS_RPC_SWAPFLAGS : 0;
177 struct rpc_task *task;
178 struct rpc_message msg = {
179 .rpc_argp = &data->args,
180 .rpc_resp = &data->res,
181 .rpc_cred = data->cred,
183 struct rpc_task_setup task_setup_data = {
187 .callback_ops = call_ops,
188 .callback_data = data,
189 .workqueue = nfsiod_workqueue,
190 .flags = RPC_TASK_ASYNC | swap_flags,
193 /* Set up the initial task struct. */
194 NFS_PROTO(inode)->read_setup(data, &msg);
196 dprintk("NFS: %5u initiated read call (req %s/%lld, %u bytes @ "
200 (long long)NFS_FILEID(inode),
202 (unsigned long long)data->args.offset);
204 task = rpc_run_task(&task_setup_data);
206 return PTR_ERR(task);
210 EXPORT_SYMBOL_GPL(nfs_initiate_read);
213 * Set up the NFS read request struct
215 static void nfs_read_rpcsetup(struct nfs_page *req, struct nfs_read_data *data,
216 unsigned int count, unsigned int offset)
218 struct inode *inode = req->wb_context->dentry->d_inode;
222 data->cred = req->wb_context->cred;
224 data->args.fh = NFS_FH(inode);
225 data->args.offset = req_offset(req) + offset;
226 data->args.pgbase = req->wb_pgbase + offset;
227 data->args.pages = data->pagevec;
228 data->args.count = count;
229 data->args.context = get_nfs_open_context(req->wb_context);
230 data->args.lock_context = req->wb_lock_context;
232 data->res.fattr = &data->fattr;
233 data->res.count = count;
235 nfs_fattr_init(&data->fattr);
238 static int nfs_do_read(struct nfs_read_data *data,
239 const struct rpc_call_ops *call_ops)
241 struct inode *inode = data->args.context->dentry->d_inode;
243 return nfs_initiate_read(data, NFS_CLIENT(inode), call_ops);
247 nfs_do_multiple_reads(struct list_head *head,
248 const struct rpc_call_ops *call_ops)
250 struct nfs_read_data *data;
253 while (!list_empty(head)) {
256 data = list_entry(head->next, struct nfs_read_data, list);
257 list_del_init(&data->list);
259 ret2 = nfs_do_read(data, call_ops);
267 nfs_async_read_error(struct list_head *head)
269 struct nfs_page *req;
271 while (!list_empty(head)) {
272 req = nfs_list_entry(head->next);
273 nfs_list_remove_request(req);
274 nfs_readpage_release(req);
279 * Generate multiple requests to fill a single page.
281 * We optimize to reduce the number of read operations on the wire. If we
282 * detect that we're reading a page, or an area of a page, that is past the
283 * end of file, we do not generate NFS read operations but just clear the
284 * parts of the page that would have come back zero from the server anyway.
286 * We rely on the cached value of i_size to make this determination; another
287 * client can fill pages on the server past our cached end-of-file, but we
288 * won't see the new data until our attribute cache is updated. This is more
289 * or less conventional NFS client behavior.
291 static int nfs_pagein_multi(struct nfs_pageio_descriptor *desc, struct list_head *res)
293 struct nfs_page *req = nfs_list_entry(desc->pg_list.next);
294 struct page *page = req->wb_page;
295 struct nfs_read_data *data;
296 size_t rsize = desc->pg_bsize, nbytes;
301 nfs_list_remove_request(req);
304 nbytes = desc->pg_count;
306 size_t len = min(nbytes,rsize);
308 data = nfs_readdata_alloc(1);
311 data->pagevec[0] = page;
312 nfs_read_rpcsetup(req, data, len, offset);
313 list_add(&data->list, res);
317 } while(nbytes != 0);
318 atomic_set(&req->wb_complete, requests);
319 desc->pg_rpc_callops = &nfs_read_partial_ops;
322 while (!list_empty(res)) {
323 data = list_entry(res->next, struct nfs_read_data, list);
324 list_del(&data->list);
325 nfs_readdata_release(data);
327 nfs_readpage_release(req);
331 static int nfs_pagein_one(struct nfs_pageio_descriptor *desc, struct list_head *res)
333 struct nfs_page *req;
335 struct nfs_read_data *data;
336 struct list_head *head = &desc->pg_list;
339 data = nfs_readdata_alloc(nfs_page_array_len(desc->pg_base,
342 nfs_async_read_error(head);
347 pages = data->pagevec;
348 while (!list_empty(head)) {
349 req = nfs_list_entry(head->next);
350 nfs_list_remove_request(req);
351 nfs_list_add_request(req, &data->pages);
352 *pages++ = req->wb_page;
354 req = nfs_list_entry(data->pages.next);
356 nfs_read_rpcsetup(req, data, desc->pg_count, 0);
357 list_add(&data->list, res);
358 desc->pg_rpc_callops = &nfs_read_full_ops;
363 int nfs_generic_pagein(struct nfs_pageio_descriptor *desc, struct list_head *head)
365 if (desc->pg_bsize < PAGE_CACHE_SIZE)
366 return nfs_pagein_multi(desc, head);
367 return nfs_pagein_one(desc, head);
370 static int nfs_generic_pg_readpages(struct nfs_pageio_descriptor *desc)
375 ret = nfs_generic_pagein(desc, &head);
377 ret = nfs_do_multiple_reads(&head, desc->pg_rpc_callops);
381 static const struct nfs_pageio_ops nfs_pageio_read_ops = {
382 .pg_test = nfs_generic_pg_test,
383 .pg_doio = nfs_generic_pg_readpages,
387 * This is the callback from RPC telling us whether a reply was
388 * received or some error occurred (timeout or socket shutdown).
390 int nfs_readpage_result(struct rpc_task *task, struct nfs_read_data *data)
394 dprintk("NFS: %s: %5u, (status %d)\n", __func__, task->tk_pid,
397 status = NFS_PROTO(data->inode)->read_done(task, data);
401 nfs_add_stats(data->inode, NFSIOS_SERVERREADBYTES, data->res.count);
403 if (task->tk_status == -ESTALE) {
404 set_bit(NFS_INO_STALE, &NFS_I(data->inode)->flags);
405 nfs_mark_for_revalidate(data->inode);
410 static void nfs_readpage_retry(struct rpc_task *task, struct nfs_read_data *data)
412 struct nfs_readargs *argp = &data->args;
413 struct nfs_readres *resp = &data->res;
415 if (resp->eof || resp->count == argp->count)
418 /* This is a short read! */
419 nfs_inc_stats(data->inode, NFSIOS_SHORTREAD);
420 /* Has the server at least made some progress? */
421 if (resp->count == 0)
424 /* Yes, so retry the read at the end of the data */
425 data->mds_offset += resp->count;
426 argp->offset += resp->count;
427 argp->pgbase += resp->count;
428 argp->count -= resp->count;
429 rpc_restart_call_prepare(task);
433 * Handle a read reply that fills part of a page.
435 static void nfs_readpage_result_partial(struct rpc_task *task, void *calldata)
437 struct nfs_read_data *data = calldata;
439 if (nfs_readpage_result(task, data) != 0)
441 if (task->tk_status < 0)
444 nfs_readpage_truncate_uninitialised_page(data);
445 nfs_readpage_retry(task, data);
448 static void nfs_readpage_release_partial(void *calldata)
450 struct nfs_read_data *data = calldata;
451 struct nfs_page *req = data->req;
452 struct page *page = req->wb_page;
453 int status = data->task.tk_status;
456 set_bit(PG_PARTIAL_READ_FAILED, &req->wb_flags);
458 if (atomic_dec_and_test(&req->wb_complete)) {
459 if (!test_bit(PG_PARTIAL_READ_FAILED, &req->wb_flags))
460 SetPageUptodate(page);
461 nfs_readpage_release(req);
463 nfs_readdata_release(calldata);
466 void nfs_read_prepare(struct rpc_task *task, void *calldata)
468 struct nfs_read_data *data = calldata;
469 NFS_PROTO(data->inode)->read_rpc_prepare(task, data);
472 static const struct rpc_call_ops nfs_read_partial_ops = {
473 .rpc_call_prepare = nfs_read_prepare,
474 .rpc_call_done = nfs_readpage_result_partial,
475 .rpc_release = nfs_readpage_release_partial,
478 static void nfs_readpage_set_pages_uptodate(struct nfs_read_data *data)
480 unsigned int count = data->res.count;
481 unsigned int base = data->args.pgbase;
485 count = data->args.count;
486 if (unlikely(count == 0))
488 pages = &data->args.pages[base >> PAGE_CACHE_SHIFT];
489 base &= ~PAGE_CACHE_MASK;
491 for (;count >= PAGE_CACHE_SIZE; count -= PAGE_CACHE_SIZE, pages++)
492 SetPageUptodate(*pages);
495 /* Was this a short read? */
496 if (data->res.eof || data->res.count == data->args.count)
497 SetPageUptodate(*pages);
501 * This is the callback from RPC telling us whether a reply was
502 * received or some error occurred (timeout or socket shutdown).
504 static void nfs_readpage_result_full(struct rpc_task *task, void *calldata)
506 struct nfs_read_data *data = calldata;
508 if (nfs_readpage_result(task, data) != 0)
510 if (task->tk_status < 0)
513 * Note: nfs_readpage_retry may change the values of
514 * data->args. In the multi-page case, we therefore need
515 * to ensure that we call nfs_readpage_set_pages_uptodate()
518 nfs_readpage_truncate_uninitialised_page(data);
519 nfs_readpage_set_pages_uptodate(data);
520 nfs_readpage_retry(task, data);
523 static void nfs_readpage_release_full(void *calldata)
525 struct nfs_read_data *data = calldata;
527 while (!list_empty(&data->pages)) {
528 struct nfs_page *req = nfs_list_entry(data->pages.next);
530 nfs_list_remove_request(req);
531 nfs_readpage_release(req);
533 nfs_readdata_release(calldata);
536 static const struct rpc_call_ops nfs_read_full_ops = {
537 .rpc_call_prepare = nfs_read_prepare,
538 .rpc_call_done = nfs_readpage_result_full,
539 .rpc_release = nfs_readpage_release_full,
543 * Read a page over NFS.
544 * We read the page synchronously in the following case:
545 * - The error flag is set for this page. This happens only when a
546 * previous async read operation failed.
548 int nfs_readpage(struct file *file, struct page *page)
550 struct nfs_open_context *ctx;
551 struct inode *inode = page->mapping->host;
554 dprintk("NFS: nfs_readpage (%p %ld@%lu)\n",
555 page, PAGE_CACHE_SIZE, page->index);
556 nfs_inc_stats(inode, NFSIOS_VFSREADPAGE);
557 nfs_add_stats(inode, NFSIOS_READPAGES, 1);
560 * Try to flush any pending writes to the file..
562 * NOTE! Because we own the page lock, there cannot
563 * be any new pending writes generated at this point
564 * for this page (other pages can be written to).
566 error = nfs_wb_page(inode, page);
569 if (PageUptodate(page))
573 if (NFS_STALE(inode))
578 ctx = nfs_find_open_context(inode, NULL, FMODE_READ);
582 ctx = get_nfs_open_context(nfs_file_open_context(file));
584 if (!IS_SYNC(inode)) {
585 error = nfs_readpage_from_fscache(ctx, inode, page);
590 error = nfs_readpage_async(ctx, inode, page);
593 put_nfs_open_context(ctx);
600 struct nfs_readdesc {
601 struct nfs_pageio_descriptor *pgio;
602 struct nfs_open_context *ctx;
606 readpage_async_filler(void *data, struct page *page)
608 struct nfs_readdesc *desc = (struct nfs_readdesc *)data;
609 struct inode *inode = page->mapping->host;
610 struct nfs_page *new;
614 len = nfs_page_length(page);
616 return nfs_return_empty_page(page);
618 new = nfs_create_request(desc->ctx, inode, page, 0, len);
622 if (len < PAGE_CACHE_SIZE)
623 zero_user_segment(page, len, PAGE_CACHE_SIZE);
624 if (!nfs_pageio_add_request(desc->pgio, new)) {
625 error = desc->pgio->pg_error;
630 error = PTR_ERR(new);
636 int nfs_readpages(struct file *filp, struct address_space *mapping,
637 struct list_head *pages, unsigned nr_pages)
639 struct nfs_pageio_descriptor pgio;
640 struct nfs_readdesc desc = {
643 struct inode *inode = mapping->host;
644 unsigned long npages;
647 dprintk("NFS: nfs_readpages (%s/%Ld %d)\n",
649 (long long)NFS_FILEID(inode),
651 nfs_inc_stats(inode, NFSIOS_VFSREADPAGES);
653 if (NFS_STALE(inode))
657 desc.ctx = nfs_find_open_context(inode, NULL, FMODE_READ);
658 if (desc.ctx == NULL)
661 desc.ctx = get_nfs_open_context(nfs_file_open_context(filp));
663 /* attempt to read as many of the pages as possible from the cache
664 * - this returns -ENOBUFS immediately if the cookie is negative
666 ret = nfs_readpages_from_fscache(desc.ctx, inode, mapping,
669 goto read_complete; /* all pages were read */
671 nfs_pageio_init_read(&pgio, inode);
673 ret = read_cache_pages(mapping, pages, readpage_async_filler, &desc);
675 nfs_pageio_complete(&pgio);
676 npages = (pgio.pg_bytes_written + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
677 nfs_add_stats(inode, NFSIOS_READPAGES, npages);
679 put_nfs_open_context(desc.ctx);
684 int __init nfs_init_readpagecache(void)
686 nfs_rdata_cachep = kmem_cache_create("nfs_read_data",
687 sizeof(struct nfs_read_data),
688 0, SLAB_HWCACHE_ALIGN,
690 if (nfs_rdata_cachep == NULL)
696 void nfs_destroy_readpagecache(void)
698 kmem_cache_destroy(nfs_rdata_cachep);