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_common_ops;
34 static const struct nfs_pgio_completion_ops nfs_async_read_completion_ops;
36 static struct kmem_cache *nfs_rdata_cachep;
38 struct nfs_read_header *nfs_readhdr_alloc(void)
40 struct nfs_read_header *rhdr;
42 rhdr = kmem_cache_zalloc(nfs_rdata_cachep, GFP_KERNEL);
44 struct nfs_pgio_header *hdr = &rhdr->header;
46 INIT_LIST_HEAD(&hdr->pages);
47 INIT_LIST_HEAD(&hdr->rpc_list);
48 spin_lock_init(&hdr->lock);
49 atomic_set(&hdr->refcnt, 0);
54 static struct nfs_read_data *nfs_readdata_alloc(struct nfs_pgio_header *hdr,
55 unsigned int pagecount)
57 struct nfs_read_data *data, *prealloc;
59 prealloc = &container_of(hdr, struct nfs_read_header, header)->rpc_data;
60 if (prealloc->header == NULL)
63 data = kzalloc(sizeof(*data), GFP_KERNEL);
67 if (nfs_pgarray_set(&data->pages, pagecount)) {
69 atomic_inc(&hdr->refcnt);
79 void nfs_readhdr_free(struct nfs_pgio_header *hdr)
81 struct nfs_read_header *rhdr = container_of(hdr, struct nfs_read_header, header);
83 kmem_cache_free(nfs_rdata_cachep, rhdr);
86 void nfs_readdata_release(struct nfs_read_data *rdata)
88 struct nfs_pgio_header *hdr = rdata->header;
89 struct nfs_read_header *read_header = container_of(hdr, struct nfs_read_header, header);
91 put_nfs_open_context(rdata->args.context);
92 if (rdata->pages.pagevec != rdata->pages.page_array)
93 kfree(rdata->pages.pagevec);
94 if (rdata != &read_header->rpc_data)
98 if (atomic_dec_and_test(&hdr->refcnt))
99 hdr->completion_ops->completion(hdr);
103 int nfs_return_empty_page(struct page *page)
105 zero_user(page, 0, PAGE_CACHE_SIZE);
106 SetPageUptodate(page);
111 void nfs_pageio_init_read_mds(struct nfs_pageio_descriptor *pgio,
113 const struct nfs_pgio_completion_ops *compl_ops)
115 nfs_pageio_init(pgio, inode, &nfs_pageio_read_ops, compl_ops,
116 NFS_SERVER(inode)->rsize, 0);
119 void nfs_pageio_reset_read_mds(struct nfs_pageio_descriptor *pgio)
121 pgio->pg_ops = &nfs_pageio_read_ops;
122 pgio->pg_bsize = NFS_SERVER(pgio->pg_inode)->rsize;
124 EXPORT_SYMBOL_GPL(nfs_pageio_reset_read_mds);
126 void nfs_pageio_init_read(struct nfs_pageio_descriptor *pgio,
128 const struct nfs_pgio_completion_ops *compl_ops)
130 if (!pnfs_pageio_init_read(pgio, inode, compl_ops))
131 nfs_pageio_init_read_mds(pgio, inode, compl_ops);
134 int nfs_readpage_async(struct nfs_open_context *ctx, struct inode *inode,
137 struct nfs_page *new;
139 struct nfs_pageio_descriptor pgio;
141 len = nfs_page_length(page);
143 return nfs_return_empty_page(page);
144 new = nfs_create_request(ctx, inode, page, 0, len);
149 if (len < PAGE_CACHE_SIZE)
150 zero_user_segment(page, len, PAGE_CACHE_SIZE);
152 nfs_pageio_init_read(&pgio, inode, &nfs_async_read_completion_ops);
153 nfs_pageio_add_request(&pgio, new);
154 nfs_pageio_complete(&pgio);
158 static void nfs_readpage_release(struct nfs_page *req)
160 struct inode *d_inode = req->wb_context->dentry->d_inode;
162 if (PageUptodate(req->wb_page))
163 nfs_readpage_to_fscache(d_inode, req->wb_page, 0);
165 unlock_page(req->wb_page);
167 dprintk("NFS: read done (%s/%Ld %d@%Ld)\n",
168 req->wb_context->dentry->d_inode->i_sb->s_id,
169 (long long)NFS_FILEID(req->wb_context->dentry->d_inode),
171 (long long)req_offset(req));
172 nfs_release_request(req);
175 /* Note io was page aligned */
176 static void nfs_read_completion(struct nfs_pgio_header *hdr)
178 unsigned long bytes = 0;
180 if (test_bit(NFS_IOHDR_REDO, &hdr->flags))
182 while (!list_empty(&hdr->pages)) {
183 struct nfs_page *req = nfs_list_entry(hdr->pages.next);
184 struct page *page = req->wb_page;
186 if (test_bit(NFS_IOHDR_EOF, &hdr->flags)) {
187 if (bytes > hdr->good_bytes)
188 zero_user(page, 0, PAGE_SIZE);
189 else if (hdr->good_bytes - bytes < PAGE_SIZE)
190 zero_user_segment(page,
191 hdr->good_bytes & ~PAGE_MASK,
194 bytes += req->wb_bytes;
195 if (test_bit(NFS_IOHDR_ERROR, &hdr->flags)) {
196 if (bytes <= hdr->good_bytes)
197 SetPageUptodate(page);
199 SetPageUptodate(page);
200 nfs_list_remove_request(req);
201 nfs_readpage_release(req);
207 int nfs_initiate_read(struct rpc_clnt *clnt,
208 struct nfs_read_data *data,
209 const struct rpc_call_ops *call_ops, int flags)
211 struct inode *inode = data->header->inode;
212 int swap_flags = IS_SWAPFILE(inode) ? NFS_RPC_SWAPFLAGS : 0;
213 struct rpc_task *task;
214 struct rpc_message msg = {
215 .rpc_argp = &data->args,
216 .rpc_resp = &data->res,
217 .rpc_cred = data->header->cred,
219 struct rpc_task_setup task_setup_data = {
223 .callback_ops = call_ops,
224 .callback_data = data,
225 .workqueue = nfsiod_workqueue,
226 .flags = RPC_TASK_ASYNC | swap_flags | flags,
229 /* Set up the initial task struct. */
230 NFS_PROTO(inode)->read_setup(data, &msg);
232 dprintk("NFS: %5u initiated read call (req %s/%lld, %u bytes @ "
236 (long long)NFS_FILEID(inode),
238 (unsigned long long)data->args.offset);
240 task = rpc_run_task(&task_setup_data);
242 return PTR_ERR(task);
246 EXPORT_SYMBOL_GPL(nfs_initiate_read);
249 * Set up the NFS read request struct
251 static void nfs_read_rpcsetup(struct nfs_read_data *data,
252 unsigned int count, unsigned int offset)
254 struct nfs_page *req = data->header->req;
256 data->args.fh = NFS_FH(data->header->inode);
257 data->args.offset = req_offset(req) + offset;
258 data->args.pgbase = req->wb_pgbase + offset;
259 data->args.pages = data->pages.pagevec;
260 data->args.count = count;
261 data->args.context = get_nfs_open_context(req->wb_context);
262 data->args.lock_context = req->wb_lock_context;
264 data->res.fattr = &data->fattr;
265 data->res.count = count;
267 nfs_fattr_init(&data->fattr);
270 static int nfs_do_read(struct nfs_read_data *data,
271 const struct rpc_call_ops *call_ops)
273 struct inode *inode = data->header->inode;
275 return nfs_initiate_read(NFS_CLIENT(inode), data, call_ops, 0);
279 nfs_do_multiple_reads(struct list_head *head,
280 const struct rpc_call_ops *call_ops)
282 struct nfs_read_data *data;
285 while (!list_empty(head)) {
288 data = list_first_entry(head, struct nfs_read_data, list);
289 list_del_init(&data->list);
291 ret2 = nfs_do_read(data, call_ops);
299 nfs_async_read_error(struct list_head *head)
301 struct nfs_page *req;
303 while (!list_empty(head)) {
304 req = nfs_list_entry(head->next);
305 nfs_list_remove_request(req);
306 nfs_readpage_release(req);
310 static const struct nfs_pgio_completion_ops nfs_async_read_completion_ops = {
311 .error_cleanup = nfs_async_read_error,
312 .completion = nfs_read_completion,
315 static void nfs_pagein_error(struct nfs_pageio_descriptor *desc,
316 struct nfs_pgio_header *hdr)
318 set_bit(NFS_IOHDR_REDO, &hdr->flags);
319 while (!list_empty(&hdr->rpc_list)) {
320 struct nfs_read_data *data = list_first_entry(&hdr->rpc_list,
321 struct nfs_read_data, list);
322 list_del(&data->list);
323 nfs_readdata_release(data);
325 desc->pg_completion_ops->error_cleanup(&desc->pg_list);
329 * Generate multiple requests to fill a single page.
331 * We optimize to reduce the number of read operations on the wire. If we
332 * detect that we're reading a page, or an area of a page, that is past the
333 * end of file, we do not generate NFS read operations but just clear the
334 * parts of the page that would have come back zero from the server anyway.
336 * We rely on the cached value of i_size to make this determination; another
337 * client can fill pages on the server past our cached end-of-file, but we
338 * won't see the new data until our attribute cache is updated. This is more
339 * or less conventional NFS client behavior.
341 static int nfs_pagein_multi(struct nfs_pageio_descriptor *desc,
342 struct nfs_pgio_header *hdr)
344 struct nfs_page *req = hdr->req;
345 struct page *page = req->wb_page;
346 struct nfs_read_data *data;
347 size_t rsize = desc->pg_bsize, nbytes;
351 nbytes = desc->pg_count;
353 size_t len = min(nbytes,rsize);
355 data = nfs_readdata_alloc(hdr, 1);
357 nfs_pagein_error(desc, hdr);
360 data->pages.pagevec[0] = page;
361 nfs_read_rpcsetup(data, len, offset);
362 list_add(&data->list, &hdr->rpc_list);
365 } while (nbytes != 0);
367 nfs_list_remove_request(req);
368 nfs_list_add_request(req, &hdr->pages);
369 desc->pg_rpc_callops = &nfs_read_common_ops;
373 static int nfs_pagein_one(struct nfs_pageio_descriptor *desc,
374 struct nfs_pgio_header *hdr)
376 struct nfs_page *req;
378 struct nfs_read_data *data;
379 struct list_head *head = &desc->pg_list;
381 data = nfs_readdata_alloc(hdr, nfs_page_array_len(desc->pg_base,
384 nfs_pagein_error(desc, hdr);
388 pages = data->pages.pagevec;
389 while (!list_empty(head)) {
390 req = nfs_list_entry(head->next);
391 nfs_list_remove_request(req);
392 nfs_list_add_request(req, &hdr->pages);
393 *pages++ = req->wb_page;
396 nfs_read_rpcsetup(data, desc->pg_count, 0);
397 list_add(&data->list, &hdr->rpc_list);
398 desc->pg_rpc_callops = &nfs_read_common_ops;
402 int nfs_generic_pagein(struct nfs_pageio_descriptor *desc,
403 struct nfs_pgio_header *hdr)
405 if (desc->pg_bsize < PAGE_CACHE_SIZE)
406 return nfs_pagein_multi(desc, hdr);
407 return nfs_pagein_one(desc, hdr);
410 static int nfs_generic_pg_readpages(struct nfs_pageio_descriptor *desc)
412 struct nfs_read_header *rhdr;
413 struct nfs_pgio_header *hdr;
416 rhdr = nfs_readhdr_alloc();
418 desc->pg_completion_ops->error_cleanup(&desc->pg_list);
422 nfs_pgheader_init(desc, hdr, nfs_readhdr_free);
423 atomic_inc(&hdr->refcnt);
424 ret = nfs_generic_pagein(desc, hdr);
426 ret = nfs_do_multiple_reads(&hdr->rpc_list,
427 desc->pg_rpc_callops);
428 if (atomic_dec_and_test(&hdr->refcnt))
429 hdr->completion_ops->completion(hdr);
433 static const struct nfs_pageio_ops nfs_pageio_read_ops = {
434 .pg_test = nfs_generic_pg_test,
435 .pg_doio = nfs_generic_pg_readpages,
439 * This is the callback from RPC telling us whether a reply was
440 * received or some error occurred (timeout or socket shutdown).
442 int nfs_readpage_result(struct rpc_task *task, struct nfs_read_data *data)
444 struct inode *inode = data->header->inode;
447 dprintk("NFS: %s: %5u, (status %d)\n", __func__, task->tk_pid,
450 status = NFS_PROTO(inode)->read_done(task, data);
454 nfs_add_stats(inode, NFSIOS_SERVERREADBYTES, data->res.count);
456 if (task->tk_status == -ESTALE) {
457 set_bit(NFS_INO_STALE, &NFS_I(inode)->flags);
458 nfs_mark_for_revalidate(inode);
463 static void nfs_readpage_retry(struct rpc_task *task, struct nfs_read_data *data)
465 struct nfs_readargs *argp = &data->args;
466 struct nfs_readres *resp = &data->res;
468 /* This is a short read! */
469 nfs_inc_stats(data->header->inode, NFSIOS_SHORTREAD);
470 /* Has the server at least made some progress? */
471 if (resp->count == 0) {
472 nfs_set_pgio_error(data->header, -EIO, argp->offset);
475 /* Yes, so retry the read at the end of the data */
476 data->mds_offset += resp->count;
477 argp->offset += resp->count;
478 argp->pgbase += resp->count;
479 argp->count -= resp->count;
480 rpc_restart_call_prepare(task);
483 static void nfs_readpage_result_common(struct rpc_task *task, void *calldata)
485 struct nfs_read_data *data = calldata;
486 struct nfs_pgio_header *hdr = data->header;
488 /* Note the only returns of nfs_readpage_result are 0 and -EAGAIN */
489 if (nfs_readpage_result(task, data) != 0)
491 if (task->tk_status < 0)
492 nfs_set_pgio_error(hdr, task->tk_status, data->args.offset);
493 else if (data->res.eof) {
496 bound = data->args.offset + data->res.count;
497 spin_lock(&hdr->lock);
498 if (bound < hdr->io_start + hdr->good_bytes) {
499 set_bit(NFS_IOHDR_EOF, &hdr->flags);
500 clear_bit(NFS_IOHDR_ERROR, &hdr->flags);
501 hdr->good_bytes = bound - hdr->io_start;
503 spin_unlock(&hdr->lock);
504 } else if (data->res.count != data->args.count)
505 nfs_readpage_retry(task, data);
508 static void nfs_readpage_release_common(void *calldata)
510 nfs_readdata_release(calldata);
513 void nfs_read_prepare(struct rpc_task *task, void *calldata)
515 struct nfs_read_data *data = calldata;
516 NFS_PROTO(data->header->inode)->read_rpc_prepare(task, data);
519 static const struct rpc_call_ops nfs_read_common_ops = {
520 .rpc_call_prepare = nfs_read_prepare,
521 .rpc_call_done = nfs_readpage_result_common,
522 .rpc_release = nfs_readpage_release_common,
526 * Read a page over NFS.
527 * We read the page synchronously in the following case:
528 * - The error flag is set for this page. This happens only when a
529 * previous async read operation failed.
531 int nfs_readpage(struct file *file, struct page *page)
533 struct nfs_open_context *ctx;
534 struct inode *inode = page->mapping->host;
537 dprintk("NFS: nfs_readpage (%p %ld@%lu)\n",
538 page, PAGE_CACHE_SIZE, page->index);
539 nfs_inc_stats(inode, NFSIOS_VFSREADPAGE);
540 nfs_add_stats(inode, NFSIOS_READPAGES, 1);
543 * Try to flush any pending writes to the file..
545 * NOTE! Because we own the page lock, there cannot
546 * be any new pending writes generated at this point
547 * for this page (other pages can be written to).
549 error = nfs_wb_page(inode, page);
552 if (PageUptodate(page))
556 if (NFS_STALE(inode))
561 ctx = nfs_find_open_context(inode, NULL, FMODE_READ);
565 ctx = get_nfs_open_context(nfs_file_open_context(file));
567 if (!IS_SYNC(inode)) {
568 error = nfs_readpage_from_fscache(ctx, inode, page);
573 error = nfs_readpage_async(ctx, inode, page);
576 put_nfs_open_context(ctx);
583 struct nfs_readdesc {
584 struct nfs_pageio_descriptor *pgio;
585 struct nfs_open_context *ctx;
589 readpage_async_filler(void *data, struct page *page)
591 struct nfs_readdesc *desc = (struct nfs_readdesc *)data;
592 struct inode *inode = page->mapping->host;
593 struct nfs_page *new;
597 len = nfs_page_length(page);
599 return nfs_return_empty_page(page);
601 new = nfs_create_request(desc->ctx, inode, page, 0, len);
605 if (len < PAGE_CACHE_SIZE)
606 zero_user_segment(page, len, PAGE_CACHE_SIZE);
607 if (!nfs_pageio_add_request(desc->pgio, new)) {
608 error = desc->pgio->pg_error;
613 error = PTR_ERR(new);
619 int nfs_readpages(struct file *filp, struct address_space *mapping,
620 struct list_head *pages, unsigned nr_pages)
622 struct nfs_pageio_descriptor pgio;
623 struct nfs_readdesc desc = {
626 struct inode *inode = mapping->host;
627 unsigned long npages;
630 dprintk("NFS: nfs_readpages (%s/%Ld %d)\n",
632 (long long)NFS_FILEID(inode),
634 nfs_inc_stats(inode, NFSIOS_VFSREADPAGES);
636 if (NFS_STALE(inode))
640 desc.ctx = nfs_find_open_context(inode, NULL, FMODE_READ);
641 if (desc.ctx == NULL)
644 desc.ctx = get_nfs_open_context(nfs_file_open_context(filp));
646 /* attempt to read as many of the pages as possible from the cache
647 * - this returns -ENOBUFS immediately if the cookie is negative
649 ret = nfs_readpages_from_fscache(desc.ctx, inode, mapping,
652 goto read_complete; /* all pages were read */
654 nfs_pageio_init_read(&pgio, inode, &nfs_async_read_completion_ops);
656 ret = read_cache_pages(mapping, pages, readpage_async_filler, &desc);
658 nfs_pageio_complete(&pgio);
659 npages = (pgio.pg_bytes_written + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
660 nfs_add_stats(inode, NFSIOS_READPAGES, npages);
662 put_nfs_open_context(desc.ctx);
667 int __init nfs_init_readpagecache(void)
669 nfs_rdata_cachep = kmem_cache_create("nfs_read_data",
670 sizeof(struct nfs_read_header),
671 0, SLAB_HWCACHE_ALIGN,
673 if (nfs_rdata_cachep == NULL)
679 void nfs_destroy_readpagecache(void)
681 kmem_cache_destroy(nfs_rdata_cachep);