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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/fs/nfs/read.c
4 *
5 * Block I/O for NFS
6 *
7 * Partial copy of Linus' read cache modifications to fs/nfs/file.c
8 * modified for async RPC by okir@monad.swb.de
9 */
10
11#include <linux/time.h>
12#include <linux/kernel.h>
13#include <linux/errno.h>
14#include <linux/fcntl.h>
15#include <linux/stat.h>
16#include <linux/mm.h>
17#include <linux/slab.h>
18#include <linux/task_io_accounting_ops.h>
19#include <linux/pagemap.h>
20#include <linux/sunrpc/clnt.h>
21#include <linux/nfs_fs.h>
22#include <linux/nfs_page.h>
23#include <linux/module.h>
24
25#include "nfs4_fs.h"
26#include "internal.h"
27#include "iostat.h"
28#include "fscache.h"
29#include "pnfs.h"
30#include "nfstrace.h"
31
32#define NFSDBG_FACILITY NFSDBG_PAGECACHE
33
34const struct nfs_pgio_completion_ops nfs_async_read_completion_ops;
35static const struct nfs_rw_ops nfs_rw_read_ops;
36
37static struct kmem_cache *nfs_rdata_cachep;
38
39static struct nfs_pgio_header *nfs_readhdr_alloc(void)
40{
41 struct nfs_pgio_header *p = kmem_cache_zalloc(nfs_rdata_cachep, GFP_KERNEL);
42
43 if (p)
44 p->rw_mode = FMODE_READ;
45 return p;
46}
47
48static void nfs_readhdr_free(struct nfs_pgio_header *rhdr)
49{
50 if (rhdr->res.scratch != NULL)
51 kfree(rhdr->res.scratch);
52 kmem_cache_free(nfs_rdata_cachep, rhdr);
53}
54
55static int nfs_return_empty_folio(struct folio *folio)
56{
57 folio_zero_segment(folio, 0, folio_size(folio));
58 folio_mark_uptodate(folio);
59 folio_unlock(folio);
60 return 0;
61}
62
63void nfs_pageio_init_read(struct nfs_pageio_descriptor *pgio,
64 struct inode *inode, bool force_mds,
65 const struct nfs_pgio_completion_ops *compl_ops)
66{
67 struct nfs_server *server = NFS_SERVER(inode);
68 const struct nfs_pageio_ops *pg_ops = &nfs_pgio_rw_ops;
69
70#ifdef CONFIG_NFS_V4_1
71 if (server->pnfs_curr_ld && !force_mds)
72 pg_ops = server->pnfs_curr_ld->pg_read_ops;
73#endif
74 nfs_pageio_init(pgio, inode, pg_ops, compl_ops, &nfs_rw_read_ops,
75 server->rsize, 0);
76}
77EXPORT_SYMBOL_GPL(nfs_pageio_init_read);
78
79void nfs_pageio_complete_read(struct nfs_pageio_descriptor *pgio)
80{
81 struct nfs_pgio_mirror *pgm;
82 unsigned long npages;
83
84 nfs_pageio_complete(pgio);
85
86 /* It doesn't make sense to do mirrored reads! */
87 WARN_ON_ONCE(pgio->pg_mirror_count != 1);
88
89 pgm = &pgio->pg_mirrors[0];
90 NFS_I(pgio->pg_inode)->read_io += pgm->pg_bytes_written;
91 npages = (pgm->pg_bytes_written + PAGE_SIZE - 1) >> PAGE_SHIFT;
92 nfs_add_stats(pgio->pg_inode, NFSIOS_READPAGES, npages);
93}
94
95
96void nfs_pageio_reset_read_mds(struct nfs_pageio_descriptor *pgio)
97{
98 struct nfs_pgio_mirror *mirror;
99
100 if (pgio->pg_ops && pgio->pg_ops->pg_cleanup)
101 pgio->pg_ops->pg_cleanup(pgio);
102
103 pgio->pg_ops = &nfs_pgio_rw_ops;
104
105 /* read path should never have more than one mirror */
106 WARN_ON_ONCE(pgio->pg_mirror_count != 1);
107
108 mirror = &pgio->pg_mirrors[0];
109 mirror->pg_bsize = NFS_SERVER(pgio->pg_inode)->rsize;
110}
111EXPORT_SYMBOL_GPL(nfs_pageio_reset_read_mds);
112
113bool nfs_read_alloc_scratch(struct nfs_pgio_header *hdr, size_t size)
114{
115 WARN_ON(hdr->res.scratch != NULL);
116 hdr->res.scratch = kmalloc(size, GFP_KERNEL);
117 return hdr->res.scratch != NULL;
118}
119EXPORT_SYMBOL_GPL(nfs_read_alloc_scratch);
120
121static void nfs_readpage_release(struct nfs_page *req, int error)
122{
123 struct folio *folio = nfs_page_to_folio(req);
124
125 if (nfs_error_is_fatal_on_server(error) && error != -ETIMEDOUT)
126 folio_set_error(folio);
127 if (nfs_page_group_sync_on_bit(req, PG_UNLOCKPAGE))
128 if (nfs_netfs_folio_unlock(folio))
129 folio_unlock(folio);
130
131 nfs_release_request(req);
132}
133
134static void nfs_page_group_set_uptodate(struct nfs_page *req)
135{
136 if (nfs_page_group_sync_on_bit(req, PG_UPTODATE))
137 folio_mark_uptodate(nfs_page_to_folio(req));
138}
139
140static void nfs_read_completion(struct nfs_pgio_header *hdr)
141{
142 unsigned long bytes = 0;
143 int error;
144
145 if (test_bit(NFS_IOHDR_REDO, &hdr->flags))
146 goto out;
147 while (!list_empty(&hdr->pages)) {
148 struct nfs_page *req = nfs_list_entry(hdr->pages.next);
149 struct folio *folio = nfs_page_to_folio(req);
150 unsigned long start = req->wb_pgbase;
151 unsigned long end = req->wb_pgbase + req->wb_bytes;
152
153 if (test_bit(NFS_IOHDR_EOF, &hdr->flags)) {
154 /* note: regions of the page not covered by a
155 * request are zeroed in nfs_read_add_folio
156 */
157 if (bytes > hdr->good_bytes) {
158 /* nothing in this request was good, so zero
159 * the full extent of the request */
160 folio_zero_segment(folio, start, end);
161
162 } else if (hdr->good_bytes - bytes < req->wb_bytes) {
163 /* part of this request has good bytes, but
164 * not all. zero the bad bytes */
165 start += hdr->good_bytes - bytes;
166 WARN_ON(start < req->wb_pgbase);
167 folio_zero_segment(folio, start, end);
168 }
169 }
170 error = 0;
171 bytes += req->wb_bytes;
172 if (test_bit(NFS_IOHDR_ERROR, &hdr->flags)) {
173 if (bytes <= hdr->good_bytes)
174 nfs_page_group_set_uptodate(req);
175 else {
176 error = hdr->error;
177 xchg(&nfs_req_openctx(req)->error, error);
178 }
179 } else
180 nfs_page_group_set_uptodate(req);
181 nfs_list_remove_request(req);
182 nfs_readpage_release(req, error);
183 }
184 nfs_netfs_read_completion(hdr);
185
186out:
187 hdr->release(hdr);
188}
189
190static void nfs_initiate_read(struct nfs_pgio_header *hdr,
191 struct rpc_message *msg,
192 const struct nfs_rpc_ops *rpc_ops,
193 struct rpc_task_setup *task_setup_data, int how)
194{
195 rpc_ops->read_setup(hdr, msg);
196 nfs_netfs_initiate_read(hdr);
197 trace_nfs_initiate_read(hdr);
198}
199
200static void
201nfs_async_read_error(struct list_head *head, int error)
202{
203 struct nfs_page *req;
204
205 while (!list_empty(head)) {
206 req = nfs_list_entry(head->next);
207 nfs_list_remove_request(req);
208 nfs_readpage_release(req, error);
209 }
210}
211
212const struct nfs_pgio_completion_ops nfs_async_read_completion_ops = {
213 .error_cleanup = nfs_async_read_error,
214 .completion = nfs_read_completion,
215};
216
217/*
218 * This is the callback from RPC telling us whether a reply was
219 * received or some error occurred (timeout or socket shutdown).
220 */
221static int nfs_readpage_done(struct rpc_task *task,
222 struct nfs_pgio_header *hdr,
223 struct inode *inode)
224{
225 int status = NFS_PROTO(inode)->read_done(task, hdr);
226 if (status != 0)
227 return status;
228
229 nfs_add_stats(inode, NFSIOS_SERVERREADBYTES, hdr->res.count);
230 trace_nfs_readpage_done(task, hdr);
231
232 if (task->tk_status == -ESTALE) {
233 nfs_set_inode_stale(inode);
234 nfs_mark_for_revalidate(inode);
235 }
236 return 0;
237}
238
239static void nfs_readpage_retry(struct rpc_task *task,
240 struct nfs_pgio_header *hdr)
241{
242 struct nfs_pgio_args *argp = &hdr->args;
243 struct nfs_pgio_res *resp = &hdr->res;
244
245 /* This is a short read! */
246 nfs_inc_stats(hdr->inode, NFSIOS_SHORTREAD);
247 trace_nfs_readpage_short(task, hdr);
248
249 /* Has the server at least made some progress? */
250 if (resp->count == 0) {
251 nfs_set_pgio_error(hdr, -EIO, argp->offset);
252 return;
253 }
254
255 /* For non rpc-based layout drivers, retry-through-MDS */
256 if (!task->tk_ops) {
257 hdr->pnfs_error = -EAGAIN;
258 return;
259 }
260
261 /* Yes, so retry the read at the end of the hdr */
262 hdr->mds_offset += resp->count;
263 argp->offset += resp->count;
264 argp->pgbase += resp->count;
265 argp->count -= resp->count;
266 resp->count = 0;
267 resp->eof = 0;
268 rpc_restart_call_prepare(task);
269}
270
271static void nfs_readpage_result(struct rpc_task *task,
272 struct nfs_pgio_header *hdr)
273{
274 if (hdr->res.eof) {
275 loff_t pos = hdr->args.offset + hdr->res.count;
276 unsigned int new = pos - hdr->io_start;
277
278 if (hdr->good_bytes > new) {
279 hdr->good_bytes = new;
280 set_bit(NFS_IOHDR_EOF, &hdr->flags);
281 clear_bit(NFS_IOHDR_ERROR, &hdr->flags);
282 }
283 } else if (hdr->res.count < hdr->args.count)
284 nfs_readpage_retry(task, hdr);
285}
286
287int nfs_read_add_folio(struct nfs_pageio_descriptor *pgio,
288 struct nfs_open_context *ctx,
289 struct folio *folio)
290{
291 struct inode *inode = folio_file_mapping(folio)->host;
292 struct nfs_server *server = NFS_SERVER(inode);
293 size_t fsize = folio_size(folio);
294 unsigned int rsize = server->rsize;
295 struct nfs_page *new;
296 unsigned int len, aligned_len;
297 int error;
298
299 len = nfs_folio_length(folio);
300 if (len == 0)
301 return nfs_return_empty_folio(folio);
302
303 aligned_len = min_t(unsigned int, ALIGN(len, rsize), fsize);
304
305 new = nfs_page_create_from_folio(ctx, folio, 0, aligned_len);
306 if (IS_ERR(new)) {
307 error = PTR_ERR(new);
308 goto out;
309 }
310
311 if (len < fsize)
312 folio_zero_segment(folio, len, fsize);
313 if (!nfs_pageio_add_request(pgio, new)) {
314 nfs_list_remove_request(new);
315 error = pgio->pg_error;
316 nfs_readpage_release(new, error);
317 goto out;
318 }
319 return 0;
320out:
321 return error;
322}
323
324/*
325 * Read a page over NFS.
326 * We read the page synchronously in the following case:
327 * - The error flag is set for this page. This happens only when a
328 * previous async read operation failed.
329 */
330int nfs_read_folio(struct file *file, struct folio *folio)
331{
332 struct inode *inode = file_inode(file);
333 struct nfs_pageio_descriptor pgio;
334 struct nfs_open_context *ctx;
335 int ret;
336
337 trace_nfs_aop_readpage(inode, folio);
338 nfs_inc_stats(inode, NFSIOS_VFSREADPAGE);
339 task_io_account_read(folio_size(folio));
340
341 /*
342 * Try to flush any pending writes to the file..
343 *
344 * NOTE! Because we own the folio lock, there cannot
345 * be any new pending writes generated at this point
346 * for this folio (other folios can be written to).
347 */
348 ret = nfs_wb_folio(inode, folio);
349 if (ret)
350 goto out_unlock;
351 if (folio_test_uptodate(folio))
352 goto out_unlock;
353
354 ret = -ESTALE;
355 if (NFS_STALE(inode))
356 goto out_unlock;
357
358 ret = nfs_netfs_read_folio(file, folio);
359 if (!ret)
360 goto out;
361
362 ctx = get_nfs_open_context(nfs_file_open_context(file));
363
364 xchg(&ctx->error, 0);
365 nfs_pageio_init_read(&pgio, inode, false,
366 &nfs_async_read_completion_ops);
367
368 ret = nfs_read_add_folio(&pgio, ctx, folio);
369 if (ret)
370 goto out_put;
371
372 nfs_pageio_complete_read(&pgio);
373 ret = pgio.pg_error < 0 ? pgio.pg_error : 0;
374 if (!ret) {
375 ret = folio_wait_locked_killable(folio);
376 if (!folio_test_uptodate(folio) && !ret)
377 ret = xchg(&ctx->error, 0);
378 }
379out_put:
380 put_nfs_open_context(ctx);
381out:
382 trace_nfs_aop_readpage_done(inode, folio, ret);
383 return ret;
384out_unlock:
385 folio_unlock(folio);
386 goto out;
387}
388
389void nfs_readahead(struct readahead_control *ractl)
390{
391 struct nfs_pageio_descriptor pgio;
392 struct nfs_open_context *ctx;
393 unsigned int nr_pages = readahead_count(ractl);
394 struct file *file = ractl->file;
395 struct inode *inode = ractl->mapping->host;
396 struct folio *folio;
397 int ret;
398
399 trace_nfs_aop_readahead(inode, readahead_pos(ractl), nr_pages);
400 nfs_inc_stats(inode, NFSIOS_VFSREADPAGES);
401 task_io_account_read(readahead_length(ractl));
402
403 ret = -ESTALE;
404 if (NFS_STALE(inode))
405 goto out;
406
407 ret = nfs_netfs_readahead(ractl);
408 if (!ret)
409 goto out;
410
411 if (file == NULL) {
412 ret = -EBADF;
413 ctx = nfs_find_open_context(inode, NULL, FMODE_READ);
414 if (ctx == NULL)
415 goto out;
416 } else
417 ctx = get_nfs_open_context(nfs_file_open_context(file));
418
419 nfs_pageio_init_read(&pgio, inode, false,
420 &nfs_async_read_completion_ops);
421
422 while ((folio = readahead_folio(ractl)) != NULL) {
423 ret = nfs_read_add_folio(&pgio, ctx, folio);
424 if (ret)
425 break;
426 }
427
428 nfs_pageio_complete_read(&pgio);
429
430 put_nfs_open_context(ctx);
431out:
432 trace_nfs_aop_readahead_done(inode, nr_pages, ret);
433}
434
435int __init nfs_init_readpagecache(void)
436{
437 nfs_rdata_cachep = kmem_cache_create("nfs_read_data",
438 sizeof(struct nfs_pgio_header),
439 0, SLAB_HWCACHE_ALIGN,
440 NULL);
441 if (nfs_rdata_cachep == NULL)
442 return -ENOMEM;
443
444 return 0;
445}
446
447void nfs_destroy_readpagecache(void)
448{
449 kmem_cache_destroy(nfs_rdata_cachep);
450}
451
452static const struct nfs_rw_ops nfs_rw_read_ops = {
453 .rw_alloc_header = nfs_readhdr_alloc,
454 .rw_free_header = nfs_readhdr_free,
455 .rw_done = nfs_readpage_done,
456 .rw_result = nfs_readpage_result,
457 .rw_initiate = nfs_initiate_read,
458};
1/*
2 * linux/fs/nfs/read.c
3 *
4 * Block I/O for NFS
5 *
6 * Partial copy of Linus' read cache modifications to fs/nfs/file.c
7 * modified for async RPC by okir@monad.swb.de
8 */
9
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>
15#include <linux/mm.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>
22
23#include <asm/system.h>
24#include "pnfs.h"
25
26#include "nfs4_fs.h"
27#include "internal.h"
28#include "iostat.h"
29#include "fscache.h"
30
31#define NFSDBG_FACILITY NFSDBG_PAGECACHE
32
33static const struct nfs_pageio_ops nfs_pageio_read_ops;
34static const struct rpc_call_ops nfs_read_partial_ops;
35static const struct rpc_call_ops nfs_read_full_ops;
36
37static struct kmem_cache *nfs_rdata_cachep;
38static mempool_t *nfs_rdata_mempool;
39
40#define MIN_POOL_READ (32)
41
42struct nfs_read_data *nfs_readdata_alloc(unsigned int pagecount)
43{
44 struct nfs_read_data *p = mempool_alloc(nfs_rdata_mempool, GFP_KERNEL);
45
46 if (p) {
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;
52 else {
53 p->pagevec = kcalloc(pagecount, sizeof(struct page *), GFP_KERNEL);
54 if (!p->pagevec) {
55 mempool_free(p, nfs_rdata_mempool);
56 p = NULL;
57 }
58 }
59 }
60 return p;
61}
62
63void nfs_readdata_free(struct nfs_read_data *p)
64{
65 if (p && (p->pagevec != &p->page_array[0]))
66 kfree(p->pagevec);
67 mempool_free(p, nfs_rdata_mempool);
68}
69
70void nfs_readdata_release(struct nfs_read_data *rdata)
71{
72 put_lseg(rdata->lseg);
73 put_nfs_open_context(rdata->args.context);
74 nfs_readdata_free(rdata);
75}
76
77static
78int nfs_return_empty_page(struct page *page)
79{
80 zero_user(page, 0, PAGE_CACHE_SIZE);
81 SetPageUptodate(page);
82 unlock_page(page);
83 return 0;
84}
85
86static void nfs_readpage_truncate_uninitialised_page(struct nfs_read_data *data)
87{
88 unsigned int remainder = data->args.count - data->res.count;
89 unsigned int base = data->args.pgbase + data->res.count;
90 unsigned int pglen;
91 struct page **pages;
92
93 if (data->res.eof == 0 || remainder == 0)
94 return;
95 /*
96 * Note: "remainder" can never be negative, since we check for
97 * this in the XDR code.
98 */
99 pages = &data->args.pages[base >> PAGE_CACHE_SHIFT];
100 base &= ~PAGE_CACHE_MASK;
101 pglen = PAGE_CACHE_SIZE - base;
102 for (;;) {
103 if (remainder <= pglen) {
104 zero_user(*pages, base, remainder);
105 break;
106 }
107 zero_user(*pages, base, pglen);
108 pages++;
109 remainder -= pglen;
110 pglen = PAGE_CACHE_SIZE;
111 base = 0;
112 }
113}
114
115static void nfs_pageio_init_read_mds(struct nfs_pageio_descriptor *pgio,
116 struct inode *inode)
117{
118 nfs_pageio_init(pgio, inode, &nfs_pageio_read_ops,
119 NFS_SERVER(inode)->rsize, 0);
120}
121
122void nfs_pageio_reset_read_mds(struct nfs_pageio_descriptor *pgio)
123{
124 pgio->pg_ops = &nfs_pageio_read_ops;
125 pgio->pg_bsize = NFS_SERVER(pgio->pg_inode)->rsize;
126}
127EXPORT_SYMBOL_GPL(nfs_pageio_reset_read_mds);
128
129static void nfs_pageio_init_read(struct nfs_pageio_descriptor *pgio,
130 struct inode *inode)
131{
132 if (!pnfs_pageio_init_read(pgio, inode))
133 nfs_pageio_init_read_mds(pgio, inode);
134}
135
136int nfs_readpage_async(struct nfs_open_context *ctx, struct inode *inode,
137 struct page *page)
138{
139 struct nfs_page *new;
140 unsigned int len;
141 struct nfs_pageio_descriptor pgio;
142
143 len = nfs_page_length(page);
144 if (len == 0)
145 return nfs_return_empty_page(page);
146 new = nfs_create_request(ctx, inode, page, 0, len);
147 if (IS_ERR(new)) {
148 unlock_page(page);
149 return PTR_ERR(new);
150 }
151 if (len < PAGE_CACHE_SIZE)
152 zero_user_segment(page, len, PAGE_CACHE_SIZE);
153
154 nfs_pageio_init_read(&pgio, inode);
155 nfs_pageio_add_request(&pgio, new);
156 nfs_pageio_complete(&pgio);
157 return 0;
158}
159
160static void nfs_readpage_release(struct nfs_page *req)
161{
162 struct inode *d_inode = req->wb_context->dentry->d_inode;
163
164 if (PageUptodate(req->wb_page))
165 nfs_readpage_to_fscache(d_inode, req->wb_page, 0);
166
167 unlock_page(req->wb_page);
168
169 dprintk("NFS: read done (%s/%Ld %d@%Ld)\n",
170 req->wb_context->dentry->d_inode->i_sb->s_id,
171 (long long)NFS_FILEID(req->wb_context->dentry->d_inode),
172 req->wb_bytes,
173 (long long)req_offset(req));
174 nfs_release_request(req);
175}
176
177int nfs_initiate_read(struct nfs_read_data *data, struct rpc_clnt *clnt,
178 const struct rpc_call_ops *call_ops)
179{
180 struct inode *inode = data->inode;
181 int swap_flags = IS_SWAPFILE(inode) ? NFS_RPC_SWAPFLAGS : 0;
182 struct rpc_task *task;
183 struct rpc_message msg = {
184 .rpc_argp = &data->args,
185 .rpc_resp = &data->res,
186 .rpc_cred = data->cred,
187 };
188 struct rpc_task_setup task_setup_data = {
189 .task = &data->task,
190 .rpc_client = clnt,
191 .rpc_message = &msg,
192 .callback_ops = call_ops,
193 .callback_data = data,
194 .workqueue = nfsiod_workqueue,
195 .flags = RPC_TASK_ASYNC | swap_flags,
196 };
197
198 /* Set up the initial task struct. */
199 NFS_PROTO(inode)->read_setup(data, &msg);
200
201 dprintk("NFS: %5u initiated read call (req %s/%lld, %u bytes @ "
202 "offset %llu)\n",
203 data->task.tk_pid,
204 inode->i_sb->s_id,
205 (long long)NFS_FILEID(inode),
206 data->args.count,
207 (unsigned long long)data->args.offset);
208
209 task = rpc_run_task(&task_setup_data);
210 if (IS_ERR(task))
211 return PTR_ERR(task);
212 rpc_put_task(task);
213 return 0;
214}
215EXPORT_SYMBOL_GPL(nfs_initiate_read);
216
217/*
218 * Set up the NFS read request struct
219 */
220static void nfs_read_rpcsetup(struct nfs_page *req, struct nfs_read_data *data,
221 unsigned int count, unsigned int offset)
222{
223 struct inode *inode = req->wb_context->dentry->d_inode;
224
225 data->req = req;
226 data->inode = inode;
227 data->cred = req->wb_context->cred;
228
229 data->args.fh = NFS_FH(inode);
230 data->args.offset = req_offset(req) + offset;
231 data->args.pgbase = req->wb_pgbase + offset;
232 data->args.pages = data->pagevec;
233 data->args.count = count;
234 data->args.context = get_nfs_open_context(req->wb_context);
235 data->args.lock_context = req->wb_lock_context;
236
237 data->res.fattr = &data->fattr;
238 data->res.count = count;
239 data->res.eof = 0;
240 nfs_fattr_init(&data->fattr);
241}
242
243static int nfs_do_read(struct nfs_read_data *data,
244 const struct rpc_call_ops *call_ops)
245{
246 struct inode *inode = data->args.context->dentry->d_inode;
247
248 return nfs_initiate_read(data, NFS_CLIENT(inode), call_ops);
249}
250
251static int
252nfs_do_multiple_reads(struct list_head *head,
253 const struct rpc_call_ops *call_ops)
254{
255 struct nfs_read_data *data;
256 int ret = 0;
257
258 while (!list_empty(head)) {
259 int ret2;
260
261 data = list_entry(head->next, struct nfs_read_data, list);
262 list_del_init(&data->list);
263
264 ret2 = nfs_do_read(data, call_ops);
265 if (ret == 0)
266 ret = ret2;
267 }
268 return ret;
269}
270
271static void
272nfs_async_read_error(struct list_head *head)
273{
274 struct nfs_page *req;
275
276 while (!list_empty(head)) {
277 req = nfs_list_entry(head->next);
278 nfs_list_remove_request(req);
279 SetPageError(req->wb_page);
280 nfs_readpage_release(req);
281 }
282}
283
284/*
285 * Generate multiple requests to fill a single page.
286 *
287 * We optimize to reduce the number of read operations on the wire. If we
288 * detect that we're reading a page, or an area of a page, that is past the
289 * end of file, we do not generate NFS read operations but just clear the
290 * parts of the page that would have come back zero from the server anyway.
291 *
292 * We rely on the cached value of i_size to make this determination; another
293 * client can fill pages on the server past our cached end-of-file, but we
294 * won't see the new data until our attribute cache is updated. This is more
295 * or less conventional NFS client behavior.
296 */
297static int nfs_pagein_multi(struct nfs_pageio_descriptor *desc, struct list_head *res)
298{
299 struct nfs_page *req = nfs_list_entry(desc->pg_list.next);
300 struct page *page = req->wb_page;
301 struct nfs_read_data *data;
302 size_t rsize = desc->pg_bsize, nbytes;
303 unsigned int offset;
304 int requests = 0;
305 int ret = 0;
306
307 nfs_list_remove_request(req);
308
309 offset = 0;
310 nbytes = desc->pg_count;
311 do {
312 size_t len = min(nbytes,rsize);
313
314 data = nfs_readdata_alloc(1);
315 if (!data)
316 goto out_bad;
317 data->pagevec[0] = page;
318 nfs_read_rpcsetup(req, data, len, offset);
319 list_add(&data->list, res);
320 requests++;
321 nbytes -= len;
322 offset += len;
323 } while(nbytes != 0);
324 atomic_set(&req->wb_complete, requests);
325 ClearPageError(page);
326 desc->pg_rpc_callops = &nfs_read_partial_ops;
327 return ret;
328out_bad:
329 while (!list_empty(res)) {
330 data = list_entry(res->next, struct nfs_read_data, list);
331 list_del(&data->list);
332 nfs_readdata_free(data);
333 }
334 SetPageError(page);
335 nfs_readpage_release(req);
336 return -ENOMEM;
337}
338
339static int nfs_pagein_one(struct nfs_pageio_descriptor *desc, struct list_head *res)
340{
341 struct nfs_page *req;
342 struct page **pages;
343 struct nfs_read_data *data;
344 struct list_head *head = &desc->pg_list;
345 int ret = 0;
346
347 data = nfs_readdata_alloc(nfs_page_array_len(desc->pg_base,
348 desc->pg_count));
349 if (!data) {
350 nfs_async_read_error(head);
351 ret = -ENOMEM;
352 goto out;
353 }
354
355 pages = data->pagevec;
356 while (!list_empty(head)) {
357 req = nfs_list_entry(head->next);
358 nfs_list_remove_request(req);
359 nfs_list_add_request(req, &data->pages);
360 ClearPageError(req->wb_page);
361 *pages++ = req->wb_page;
362 }
363 req = nfs_list_entry(data->pages.next);
364
365 nfs_read_rpcsetup(req, data, desc->pg_count, 0);
366 list_add(&data->list, res);
367 desc->pg_rpc_callops = &nfs_read_full_ops;
368out:
369 return ret;
370}
371
372int nfs_generic_pagein(struct nfs_pageio_descriptor *desc, struct list_head *head)
373{
374 if (desc->pg_bsize < PAGE_CACHE_SIZE)
375 return nfs_pagein_multi(desc, head);
376 return nfs_pagein_one(desc, head);
377}
378
379static int nfs_generic_pg_readpages(struct nfs_pageio_descriptor *desc)
380{
381 LIST_HEAD(head);
382 int ret;
383
384 ret = nfs_generic_pagein(desc, &head);
385 if (ret == 0)
386 ret = nfs_do_multiple_reads(&head, desc->pg_rpc_callops);
387 return ret;
388}
389
390static const struct nfs_pageio_ops nfs_pageio_read_ops = {
391 .pg_test = nfs_generic_pg_test,
392 .pg_doio = nfs_generic_pg_readpages,
393};
394
395/*
396 * This is the callback from RPC telling us whether a reply was
397 * received or some error occurred (timeout or socket shutdown).
398 */
399int nfs_readpage_result(struct rpc_task *task, struct nfs_read_data *data)
400{
401 int status;
402
403 dprintk("NFS: %s: %5u, (status %d)\n", __func__, task->tk_pid,
404 task->tk_status);
405
406 status = NFS_PROTO(data->inode)->read_done(task, data);
407 if (status != 0)
408 return status;
409
410 nfs_add_stats(data->inode, NFSIOS_SERVERREADBYTES, data->res.count);
411
412 if (task->tk_status == -ESTALE) {
413 set_bit(NFS_INO_STALE, &NFS_I(data->inode)->flags);
414 nfs_mark_for_revalidate(data->inode);
415 }
416 return 0;
417}
418
419static void nfs_readpage_retry(struct rpc_task *task, struct nfs_read_data *data)
420{
421 struct nfs_readargs *argp = &data->args;
422 struct nfs_readres *resp = &data->res;
423
424 if (resp->eof || resp->count == argp->count)
425 return;
426
427 /* This is a short read! */
428 nfs_inc_stats(data->inode, NFSIOS_SHORTREAD);
429 /* Has the server at least made some progress? */
430 if (resp->count == 0)
431 return;
432
433 /* Yes, so retry the read at the end of the data */
434 data->mds_offset += resp->count;
435 argp->offset += resp->count;
436 argp->pgbase += resp->count;
437 argp->count -= resp->count;
438 nfs_restart_rpc(task, NFS_SERVER(data->inode)->nfs_client);
439}
440
441/*
442 * Handle a read reply that fills part of a page.
443 */
444static void nfs_readpage_result_partial(struct rpc_task *task, void *calldata)
445{
446 struct nfs_read_data *data = calldata;
447
448 if (nfs_readpage_result(task, data) != 0)
449 return;
450 if (task->tk_status < 0)
451 return;
452
453 nfs_readpage_truncate_uninitialised_page(data);
454 nfs_readpage_retry(task, data);
455}
456
457static void nfs_readpage_release_partial(void *calldata)
458{
459 struct nfs_read_data *data = calldata;
460 struct nfs_page *req = data->req;
461 struct page *page = req->wb_page;
462 int status = data->task.tk_status;
463
464 if (status < 0)
465 SetPageError(page);
466
467 if (atomic_dec_and_test(&req->wb_complete)) {
468 if (!PageError(page))
469 SetPageUptodate(page);
470 nfs_readpage_release(req);
471 }
472 nfs_readdata_release(calldata);
473}
474
475#if defined(CONFIG_NFS_V4_1)
476void nfs_read_prepare(struct rpc_task *task, void *calldata)
477{
478 struct nfs_read_data *data = calldata;
479
480 if (nfs4_setup_sequence(NFS_SERVER(data->inode),
481 &data->args.seq_args, &data->res.seq_res,
482 0, task))
483 return;
484 rpc_call_start(task);
485}
486#endif /* CONFIG_NFS_V4_1 */
487
488static const struct rpc_call_ops nfs_read_partial_ops = {
489#if defined(CONFIG_NFS_V4_1)
490 .rpc_call_prepare = nfs_read_prepare,
491#endif /* CONFIG_NFS_V4_1 */
492 .rpc_call_done = nfs_readpage_result_partial,
493 .rpc_release = nfs_readpage_release_partial,
494};
495
496static void nfs_readpage_set_pages_uptodate(struct nfs_read_data *data)
497{
498 unsigned int count = data->res.count;
499 unsigned int base = data->args.pgbase;
500 struct page **pages;
501
502 if (data->res.eof)
503 count = data->args.count;
504 if (unlikely(count == 0))
505 return;
506 pages = &data->args.pages[base >> PAGE_CACHE_SHIFT];
507 base &= ~PAGE_CACHE_MASK;
508 count += base;
509 for (;count >= PAGE_CACHE_SIZE; count -= PAGE_CACHE_SIZE, pages++)
510 SetPageUptodate(*pages);
511 if (count == 0)
512 return;
513 /* Was this a short read? */
514 if (data->res.eof || data->res.count == data->args.count)
515 SetPageUptodate(*pages);
516}
517
518/*
519 * This is the callback from RPC telling us whether a reply was
520 * received or some error occurred (timeout or socket shutdown).
521 */
522static void nfs_readpage_result_full(struct rpc_task *task, void *calldata)
523{
524 struct nfs_read_data *data = calldata;
525
526 if (nfs_readpage_result(task, data) != 0)
527 return;
528 if (task->tk_status < 0)
529 return;
530 /*
531 * Note: nfs_readpage_retry may change the values of
532 * data->args. In the multi-page case, we therefore need
533 * to ensure that we call nfs_readpage_set_pages_uptodate()
534 * first.
535 */
536 nfs_readpage_truncate_uninitialised_page(data);
537 nfs_readpage_set_pages_uptodate(data);
538 nfs_readpage_retry(task, data);
539}
540
541static void nfs_readpage_release_full(void *calldata)
542{
543 struct nfs_read_data *data = calldata;
544
545 while (!list_empty(&data->pages)) {
546 struct nfs_page *req = nfs_list_entry(data->pages.next);
547
548 nfs_list_remove_request(req);
549 nfs_readpage_release(req);
550 }
551 nfs_readdata_release(calldata);
552}
553
554static const struct rpc_call_ops nfs_read_full_ops = {
555#if defined(CONFIG_NFS_V4_1)
556 .rpc_call_prepare = nfs_read_prepare,
557#endif /* CONFIG_NFS_V4_1 */
558 .rpc_call_done = nfs_readpage_result_full,
559 .rpc_release = nfs_readpage_release_full,
560};
561
562/*
563 * Read a page over NFS.
564 * We read the page synchronously in the following case:
565 * - The error flag is set for this page. This happens only when a
566 * previous async read operation failed.
567 */
568int nfs_readpage(struct file *file, struct page *page)
569{
570 struct nfs_open_context *ctx;
571 struct inode *inode = page->mapping->host;
572 int error;
573
574 dprintk("NFS: nfs_readpage (%p %ld@%lu)\n",
575 page, PAGE_CACHE_SIZE, page->index);
576 nfs_inc_stats(inode, NFSIOS_VFSREADPAGE);
577 nfs_add_stats(inode, NFSIOS_READPAGES, 1);
578
579 /*
580 * Try to flush any pending writes to the file..
581 *
582 * NOTE! Because we own the page lock, there cannot
583 * be any new pending writes generated at this point
584 * for this page (other pages can be written to).
585 */
586 error = nfs_wb_page(inode, page);
587 if (error)
588 goto out_unlock;
589 if (PageUptodate(page))
590 goto out_unlock;
591
592 error = -ESTALE;
593 if (NFS_STALE(inode))
594 goto out_unlock;
595
596 if (file == NULL) {
597 error = -EBADF;
598 ctx = nfs_find_open_context(inode, NULL, FMODE_READ);
599 if (ctx == NULL)
600 goto out_unlock;
601 } else
602 ctx = get_nfs_open_context(nfs_file_open_context(file));
603
604 if (!IS_SYNC(inode)) {
605 error = nfs_readpage_from_fscache(ctx, inode, page);
606 if (error == 0)
607 goto out;
608 }
609
610 error = nfs_readpage_async(ctx, inode, page);
611
612out:
613 put_nfs_open_context(ctx);
614 return error;
615out_unlock:
616 unlock_page(page);
617 return error;
618}
619
620struct nfs_readdesc {
621 struct nfs_pageio_descriptor *pgio;
622 struct nfs_open_context *ctx;
623};
624
625static int
626readpage_async_filler(void *data, struct page *page)
627{
628 struct nfs_readdesc *desc = (struct nfs_readdesc *)data;
629 struct inode *inode = page->mapping->host;
630 struct nfs_page *new;
631 unsigned int len;
632 int error;
633
634 len = nfs_page_length(page);
635 if (len == 0)
636 return nfs_return_empty_page(page);
637
638 new = nfs_create_request(desc->ctx, inode, page, 0, len);
639 if (IS_ERR(new))
640 goto out_error;
641
642 if (len < PAGE_CACHE_SIZE)
643 zero_user_segment(page, len, PAGE_CACHE_SIZE);
644 if (!nfs_pageio_add_request(desc->pgio, new)) {
645 error = desc->pgio->pg_error;
646 goto out_unlock;
647 }
648 return 0;
649out_error:
650 error = PTR_ERR(new);
651 SetPageError(page);
652out_unlock:
653 unlock_page(page);
654 return error;
655}
656
657int nfs_readpages(struct file *filp, struct address_space *mapping,
658 struct list_head *pages, unsigned nr_pages)
659{
660 struct nfs_pageio_descriptor pgio;
661 struct nfs_readdesc desc = {
662 .pgio = &pgio,
663 };
664 struct inode *inode = mapping->host;
665 unsigned long npages;
666 int ret = -ESTALE;
667
668 dprintk("NFS: nfs_readpages (%s/%Ld %d)\n",
669 inode->i_sb->s_id,
670 (long long)NFS_FILEID(inode),
671 nr_pages);
672 nfs_inc_stats(inode, NFSIOS_VFSREADPAGES);
673
674 if (NFS_STALE(inode))
675 goto out;
676
677 if (filp == NULL) {
678 desc.ctx = nfs_find_open_context(inode, NULL, FMODE_READ);
679 if (desc.ctx == NULL)
680 return -EBADF;
681 } else
682 desc.ctx = get_nfs_open_context(nfs_file_open_context(filp));
683
684 /* attempt to read as many of the pages as possible from the cache
685 * - this returns -ENOBUFS immediately if the cookie is negative
686 */
687 ret = nfs_readpages_from_fscache(desc.ctx, inode, mapping,
688 pages, &nr_pages);
689 if (ret == 0)
690 goto read_complete; /* all pages were read */
691
692 nfs_pageio_init_read(&pgio, inode);
693
694 ret = read_cache_pages(mapping, pages, readpage_async_filler, &desc);
695
696 nfs_pageio_complete(&pgio);
697 npages = (pgio.pg_bytes_written + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
698 nfs_add_stats(inode, NFSIOS_READPAGES, npages);
699read_complete:
700 put_nfs_open_context(desc.ctx);
701out:
702 return ret;
703}
704
705int __init nfs_init_readpagecache(void)
706{
707 nfs_rdata_cachep = kmem_cache_create("nfs_read_data",
708 sizeof(struct nfs_read_data),
709 0, SLAB_HWCACHE_ALIGN,
710 NULL);
711 if (nfs_rdata_cachep == NULL)
712 return -ENOMEM;
713
714 nfs_rdata_mempool = mempool_create_slab_pool(MIN_POOL_READ,
715 nfs_rdata_cachep);
716 if (nfs_rdata_mempool == NULL)
717 return -ENOMEM;
718
719 return 0;
720}
721
722void nfs_destroy_readpagecache(void)
723{
724 mempool_destroy(nfs_rdata_mempool);
725 kmem_cache_destroy(nfs_rdata_cachep);
726}