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>
22 #include <asm/system.h>
30 #define NFSDBG_FACILITY NFSDBG_PAGECACHE
32 static int nfs_pagein_multi(struct inode *, struct list_head *, unsigned int, size_t, int);
33 static int nfs_pagein_one(struct inode *, struct list_head *, unsigned int, size_t, int);
34 static const struct rpc_call_ops nfs_read_partial_ops;
35 static const struct rpc_call_ops nfs_read_full_ops;
37 static struct kmem_cache *nfs_rdata_cachep;
38 static mempool_t *nfs_rdata_mempool;
40 #define MIN_POOL_READ (32)
42 struct nfs_read_data *nfs_readdata_alloc(unsigned int pagecount)
44 struct nfs_read_data *p = mempool_alloc(nfs_rdata_mempool, GFP_KERNEL);
47 memset(p, 0, sizeof(*p));
48 INIT_LIST_HEAD(&p->pages);
49 p->npages = pagecount;
50 if (pagecount <= ARRAY_SIZE(p->page_array))
51 p->pagevec = p->page_array;
53 p->pagevec = kcalloc(pagecount, sizeof(struct page *), GFP_KERNEL);
55 mempool_free(p, nfs_rdata_mempool);
63 void nfs_readdata_free(struct nfs_read_data *p)
65 if (p && (p->pagevec != &p->page_array[0]))
67 mempool_free(p, nfs_rdata_mempool);
70 static void nfs_readdata_release(struct nfs_read_data *rdata)
72 put_nfs_open_context(rdata->args.context);
73 nfs_readdata_free(rdata);
77 int nfs_return_empty_page(struct page *page)
79 zero_user(page, 0, PAGE_CACHE_SIZE);
80 SetPageUptodate(page);
85 static void nfs_readpage_truncate_uninitialised_page(struct nfs_read_data *data)
87 unsigned int remainder = data->args.count - data->res.count;
88 unsigned int base = data->args.pgbase + data->res.count;
92 if (data->res.eof == 0 || remainder == 0)
95 * Note: "remainder" can never be negative, since we check for
96 * this in the XDR code.
98 pages = &data->args.pages[base >> PAGE_CACHE_SHIFT];
99 base &= ~PAGE_CACHE_MASK;
100 pglen = PAGE_CACHE_SIZE - base;
102 if (remainder <= pglen) {
103 zero_user(*pages, base, remainder);
106 zero_user(*pages, base, pglen);
109 pglen = PAGE_CACHE_SIZE;
114 int nfs_readpage_async(struct nfs_open_context *ctx, struct inode *inode,
117 LIST_HEAD(one_request);
118 struct nfs_page *new;
121 len = nfs_page_length(page);
123 return nfs_return_empty_page(page);
124 pnfs_update_layout(inode, ctx, IOMODE_READ);
125 new = nfs_create_request(ctx, inode, page, 0, len);
130 if (len < PAGE_CACHE_SIZE)
131 zero_user_segment(page, len, PAGE_CACHE_SIZE);
133 nfs_list_add_request(new, &one_request);
134 if (NFS_SERVER(inode)->rsize < PAGE_CACHE_SIZE)
135 nfs_pagein_multi(inode, &one_request, 1, len, 0);
137 nfs_pagein_one(inode, &one_request, 1, len, 0);
141 static void nfs_readpage_release(struct nfs_page *req)
143 struct inode *d_inode = req->wb_context->path.dentry->d_inode;
145 if (PageUptodate(req->wb_page))
146 nfs_readpage_to_fscache(d_inode, req->wb_page, 0);
148 unlock_page(req->wb_page);
150 dprintk("NFS: read done (%s/%Ld %d@%Ld)\n",
151 req->wb_context->path.dentry->d_inode->i_sb->s_id,
152 (long long)NFS_FILEID(req->wb_context->path.dentry->d_inode),
154 (long long)req_offset(req));
155 nfs_clear_request(req);
156 nfs_release_request(req);
160 * Set up the NFS read request struct
162 static int nfs_read_rpcsetup(struct nfs_page *req, struct nfs_read_data *data,
163 const struct rpc_call_ops *call_ops,
164 unsigned int count, unsigned int offset)
166 struct inode *inode = req->wb_context->path.dentry->d_inode;
167 int swap_flags = IS_SWAPFILE(inode) ? NFS_RPC_SWAPFLAGS : 0;
168 struct rpc_task *task;
169 struct rpc_message msg = {
170 .rpc_argp = &data->args,
171 .rpc_resp = &data->res,
172 .rpc_cred = req->wb_context->cred,
174 struct rpc_task_setup task_setup_data = {
176 .rpc_client = NFS_CLIENT(inode),
178 .callback_ops = call_ops,
179 .callback_data = data,
180 .workqueue = nfsiod_workqueue,
181 .flags = RPC_TASK_ASYNC | swap_flags,
186 data->cred = msg.rpc_cred;
188 data->args.fh = NFS_FH(inode);
189 data->args.offset = req_offset(req) + offset;
190 data->args.pgbase = req->wb_pgbase + offset;
191 data->args.pages = data->pagevec;
192 data->args.count = count;
193 data->args.context = get_nfs_open_context(req->wb_context);
194 data->args.lock_context = req->wb_lock_context;
196 data->res.fattr = &data->fattr;
197 data->res.count = count;
199 nfs_fattr_init(&data->fattr);
201 /* Set up the initial task struct. */
202 NFS_PROTO(inode)->read_setup(data, &msg);
204 dprintk("NFS: %5u initiated read call (req %s/%Ld, %u bytes @ offset %Lu)\n",
207 (long long)NFS_FILEID(inode),
209 (unsigned long long)data->args.offset);
211 task = rpc_run_task(&task_setup_data);
213 return PTR_ERR(task);
219 nfs_async_read_error(struct list_head *head)
221 struct nfs_page *req;
223 while (!list_empty(head)) {
224 req = nfs_list_entry(head->next);
225 nfs_list_remove_request(req);
226 SetPageError(req->wb_page);
227 nfs_readpage_release(req);
232 * Generate multiple requests to fill a single page.
234 * We optimize to reduce the number of read operations on the wire. If we
235 * detect that we're reading a page, or an area of a page, that is past the
236 * end of file, we do not generate NFS read operations but just clear the
237 * parts of the page that would have come back zero from the server anyway.
239 * We rely on the cached value of i_size to make this determination; another
240 * client can fill pages on the server past our cached end-of-file, but we
241 * won't see the new data until our attribute cache is updated. This is more
242 * or less conventional NFS client behavior.
244 static int nfs_pagein_multi(struct inode *inode, struct list_head *head, unsigned int npages, size_t count, int flags)
246 struct nfs_page *req = nfs_list_entry(head->next);
247 struct page *page = req->wb_page;
248 struct nfs_read_data *data;
249 size_t rsize = NFS_SERVER(inode)->rsize, nbytes;
255 nfs_list_remove_request(req);
259 size_t len = min(nbytes,rsize);
261 data = nfs_readdata_alloc(1);
264 list_add(&data->pages, &list);
267 } while(nbytes != 0);
268 atomic_set(&req->wb_complete, requests);
270 ClearPageError(page);
276 data = list_entry(list.next, struct nfs_read_data, pages);
277 list_del_init(&data->pages);
279 data->pagevec[0] = page;
283 ret2 = nfs_read_rpcsetup(req, data, &nfs_read_partial_ops,
289 } while (nbytes != 0);
294 while (!list_empty(&list)) {
295 data = list_entry(list.next, struct nfs_read_data, pages);
296 list_del(&data->pages);
297 nfs_readdata_free(data);
300 nfs_readpage_release(req);
304 static int nfs_pagein_one(struct inode *inode, struct list_head *head, unsigned int npages, size_t count, int flags)
306 struct nfs_page *req;
308 struct nfs_read_data *data;
311 data = nfs_readdata_alloc(npages);
315 pages = data->pagevec;
316 while (!list_empty(head)) {
317 req = nfs_list_entry(head->next);
318 nfs_list_remove_request(req);
319 nfs_list_add_request(req, &data->pages);
320 ClearPageError(req->wb_page);
321 *pages++ = req->wb_page;
323 req = nfs_list_entry(data->pages.next);
325 return nfs_read_rpcsetup(req, data, &nfs_read_full_ops, count, 0);
327 nfs_async_read_error(head);
332 * This is the callback from RPC telling us whether a reply was
333 * received or some error occurred (timeout or socket shutdown).
335 int nfs_readpage_result(struct rpc_task *task, struct nfs_read_data *data)
339 dprintk("NFS: %s: %5u, (status %d)\n", __func__, task->tk_pid,
342 status = NFS_PROTO(data->inode)->read_done(task, data);
346 nfs_add_stats(data->inode, NFSIOS_SERVERREADBYTES, data->res.count);
348 if (task->tk_status == -ESTALE) {
349 set_bit(NFS_INO_STALE, &NFS_I(data->inode)->flags);
350 nfs_mark_for_revalidate(data->inode);
355 static void nfs_readpage_retry(struct rpc_task *task, struct nfs_read_data *data)
357 struct nfs_readargs *argp = &data->args;
358 struct nfs_readres *resp = &data->res;
360 if (resp->eof || resp->count == argp->count)
363 /* This is a short read! */
364 nfs_inc_stats(data->inode, NFSIOS_SHORTREAD);
365 /* Has the server at least made some progress? */
366 if (resp->count == 0)
369 /* Yes, so retry the read at the end of the data */
370 argp->offset += resp->count;
371 argp->pgbase += resp->count;
372 argp->count -= resp->count;
373 nfs_restart_rpc(task, NFS_SERVER(data->inode)->nfs_client);
377 * Handle a read reply that fills part of a page.
379 static void nfs_readpage_result_partial(struct rpc_task *task, void *calldata)
381 struct nfs_read_data *data = calldata;
383 if (nfs_readpage_result(task, data) != 0)
385 if (task->tk_status < 0)
388 nfs_readpage_truncate_uninitialised_page(data);
389 nfs_readpage_retry(task, data);
392 static void nfs_readpage_release_partial(void *calldata)
394 struct nfs_read_data *data = calldata;
395 struct nfs_page *req = data->req;
396 struct page *page = req->wb_page;
397 int status = data->task.tk_status;
402 if (atomic_dec_and_test(&req->wb_complete)) {
403 if (!PageError(page))
404 SetPageUptodate(page);
405 nfs_readpage_release(req);
407 nfs_readdata_release(calldata);
410 #if defined(CONFIG_NFS_V4_1)
411 void nfs_read_prepare(struct rpc_task *task, void *calldata)
413 struct nfs_read_data *data = calldata;
415 if (nfs4_setup_sequence(NFS_SERVER(data->inode),
416 &data->args.seq_args, &data->res.seq_res,
419 rpc_call_start(task);
421 #endif /* CONFIG_NFS_V4_1 */
423 static const struct rpc_call_ops nfs_read_partial_ops = {
424 #if defined(CONFIG_NFS_V4_1)
425 .rpc_call_prepare = nfs_read_prepare,
426 #endif /* CONFIG_NFS_V4_1 */
427 .rpc_call_done = nfs_readpage_result_partial,
428 .rpc_release = nfs_readpage_release_partial,
431 static void nfs_readpage_set_pages_uptodate(struct nfs_read_data *data)
433 unsigned int count = data->res.count;
434 unsigned int base = data->args.pgbase;
438 count = data->args.count;
439 if (unlikely(count == 0))
441 pages = &data->args.pages[base >> PAGE_CACHE_SHIFT];
442 base &= ~PAGE_CACHE_MASK;
444 for (;count >= PAGE_CACHE_SIZE; count -= PAGE_CACHE_SIZE, pages++)
445 SetPageUptodate(*pages);
448 /* Was this a short read? */
449 if (data->res.eof || data->res.count == data->args.count)
450 SetPageUptodate(*pages);
454 * This is the callback from RPC telling us whether a reply was
455 * received or some error occurred (timeout or socket shutdown).
457 static void nfs_readpage_result_full(struct rpc_task *task, void *calldata)
459 struct nfs_read_data *data = calldata;
461 if (nfs_readpage_result(task, data) != 0)
463 if (task->tk_status < 0)
466 * Note: nfs_readpage_retry may change the values of
467 * data->args. In the multi-page case, we therefore need
468 * to ensure that we call nfs_readpage_set_pages_uptodate()
471 nfs_readpage_truncate_uninitialised_page(data);
472 nfs_readpage_set_pages_uptodate(data);
473 nfs_readpage_retry(task, data);
476 static void nfs_readpage_release_full(void *calldata)
478 struct nfs_read_data *data = calldata;
480 while (!list_empty(&data->pages)) {
481 struct nfs_page *req = nfs_list_entry(data->pages.next);
483 nfs_list_remove_request(req);
484 nfs_readpage_release(req);
486 nfs_readdata_release(calldata);
489 static const struct rpc_call_ops nfs_read_full_ops = {
490 #if defined(CONFIG_NFS_V4_1)
491 .rpc_call_prepare = nfs_read_prepare,
492 #endif /* CONFIG_NFS_V4_1 */
493 .rpc_call_done = nfs_readpage_result_full,
494 .rpc_release = nfs_readpage_release_full,
498 * Read a page over NFS.
499 * We read the page synchronously in the following case:
500 * - The error flag is set for this page. This happens only when a
501 * previous async read operation failed.
503 int nfs_readpage(struct file *file, struct page *page)
505 struct nfs_open_context *ctx;
506 struct inode *inode = page->mapping->host;
509 dprintk("NFS: nfs_readpage (%p %ld@%lu)\n",
510 page, PAGE_CACHE_SIZE, page->index);
511 nfs_inc_stats(inode, NFSIOS_VFSREADPAGE);
512 nfs_add_stats(inode, NFSIOS_READPAGES, 1);
515 * Try to flush any pending writes to the file..
517 * NOTE! Because we own the page lock, there cannot
518 * be any new pending writes generated at this point
519 * for this page (other pages can be written to).
521 error = nfs_wb_page(inode, page);
524 if (PageUptodate(page))
528 if (NFS_STALE(inode))
533 ctx = nfs_find_open_context(inode, NULL, FMODE_READ);
537 ctx = get_nfs_open_context(nfs_file_open_context(file));
539 if (!IS_SYNC(inode)) {
540 error = nfs_readpage_from_fscache(ctx, inode, page);
545 error = nfs_readpage_async(ctx, inode, page);
548 put_nfs_open_context(ctx);
555 struct nfs_readdesc {
556 struct nfs_pageio_descriptor *pgio;
557 struct nfs_open_context *ctx;
561 readpage_async_filler(void *data, struct page *page)
563 struct nfs_readdesc *desc = (struct nfs_readdesc *)data;
564 struct inode *inode = page->mapping->host;
565 struct nfs_page *new;
569 len = nfs_page_length(page);
571 return nfs_return_empty_page(page);
573 new = nfs_create_request(desc->ctx, inode, page, 0, len);
577 if (len < PAGE_CACHE_SIZE)
578 zero_user_segment(page, len, PAGE_CACHE_SIZE);
579 if (!nfs_pageio_add_request(desc->pgio, new)) {
580 error = desc->pgio->pg_error;
585 error = PTR_ERR(new);
592 int nfs_readpages(struct file *filp, struct address_space *mapping,
593 struct list_head *pages, unsigned nr_pages)
595 struct nfs_pageio_descriptor pgio;
596 struct nfs_readdesc desc = {
599 struct inode *inode = mapping->host;
600 struct nfs_server *server = NFS_SERVER(inode);
601 size_t rsize = server->rsize;
602 unsigned long npages;
605 dprintk("NFS: nfs_readpages (%s/%Ld %d)\n",
607 (long long)NFS_FILEID(inode),
609 nfs_inc_stats(inode, NFSIOS_VFSREADPAGES);
611 if (NFS_STALE(inode))
615 desc.ctx = nfs_find_open_context(inode, NULL, FMODE_READ);
616 if (desc.ctx == NULL)
619 desc.ctx = get_nfs_open_context(nfs_file_open_context(filp));
621 /* attempt to read as many of the pages as possible from the cache
622 * - this returns -ENOBUFS immediately if the cookie is negative
624 ret = nfs_readpages_from_fscache(desc.ctx, inode, mapping,
627 goto read_complete; /* all pages were read */
629 pnfs_update_layout(inode, desc.ctx, IOMODE_READ);
630 if (rsize < PAGE_CACHE_SIZE)
631 nfs_pageio_init(&pgio, inode, nfs_pagein_multi, rsize, 0);
633 nfs_pageio_init(&pgio, inode, nfs_pagein_one, rsize, 0);
635 ret = read_cache_pages(mapping, pages, readpage_async_filler, &desc);
637 nfs_pageio_complete(&pgio);
638 npages = (pgio.pg_bytes_written + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
639 nfs_add_stats(inode, NFSIOS_READPAGES, npages);
641 put_nfs_open_context(desc.ctx);
646 int __init nfs_init_readpagecache(void)
648 nfs_rdata_cachep = kmem_cache_create("nfs_read_data",
649 sizeof(struct nfs_read_data),
650 0, SLAB_HWCACHE_ALIGN,
652 if (nfs_rdata_cachep == NULL)
655 nfs_rdata_mempool = mempool_create_slab_pool(MIN_POOL_READ,
657 if (nfs_rdata_mempool == NULL)
663 void nfs_destroy_readpagecache(void)
665 mempool_destroy(nfs_rdata_mempool);
666 kmem_cache_destroy(nfs_rdata_cachep);