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Commit | Line | Data |
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1da177e4 LT |
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 | ||
1da177e4 LT |
12 | #include <linux/slab.h> |
13 | #include <linux/file.h> | |
14 | #include <linux/sunrpc/clnt.h> | |
15 | #include <linux/nfs3.h> | |
16 | #include <linux/nfs4.h> | |
17 | #include <linux/nfs_page.h> | |
18 | #include <linux/nfs_fs.h> | |
19 | #include <linux/nfs_mount.h> | |
20 | ||
8d5658c9 TM |
21 | #include "internal.h" |
22 | ||
1da177e4 LT |
23 | #define NFS_PARANOIA 1 |
24 | ||
e18b890b | 25 | static struct kmem_cache *nfs_page_cachep; |
1da177e4 LT |
26 | |
27 | static inline struct nfs_page * | |
28 | nfs_page_alloc(void) | |
29 | { | |
30 | struct nfs_page *p; | |
e94b1766 | 31 | p = kmem_cache_alloc(nfs_page_cachep, GFP_KERNEL); |
1da177e4 LT |
32 | if (p) { |
33 | memset(p, 0, sizeof(*p)); | |
34 | INIT_LIST_HEAD(&p->wb_list); | |
35 | } | |
36 | return p; | |
37 | } | |
38 | ||
39 | static inline void | |
40 | nfs_page_free(struct nfs_page *p) | |
41 | { | |
42 | kmem_cache_free(nfs_page_cachep, p); | |
43 | } | |
44 | ||
45 | /** | |
46 | * nfs_create_request - Create an NFS read/write request. | |
47 | * @file: file descriptor to use | |
48 | * @inode: inode to which the request is attached | |
49 | * @page: page to write | |
50 | * @offset: starting offset within the page for the write | |
51 | * @count: number of bytes to read/write | |
52 | * | |
53 | * The page must be locked by the caller. This makes sure we never | |
a19b89ca | 54 | * create two different requests for the same page. |
1da177e4 LT |
55 | * User should ensure it is safe to sleep in this function. |
56 | */ | |
57 | struct nfs_page * | |
58 | nfs_create_request(struct nfs_open_context *ctx, struct inode *inode, | |
59 | struct page *page, | |
60 | unsigned int offset, unsigned int count) | |
61 | { | |
62 | struct nfs_server *server = NFS_SERVER(inode); | |
63 | struct nfs_page *req; | |
64 | ||
1da177e4 LT |
65 | for (;;) { |
66 | /* try to allocate the request struct */ | |
67 | req = nfs_page_alloc(); | |
68 | if (req != NULL) | |
69 | break; | |
70 | ||
1da177e4 LT |
71 | if (signalled() && (server->flags & NFS_MOUNT_INTR)) |
72 | return ERR_PTR(-ERESTARTSYS); | |
73 | yield(); | |
74 | } | |
75 | ||
76 | /* Initialize the request struct. Initially, we assume a | |
77 | * long write-back delay. This will be adjusted in | |
78 | * update_nfs_request below if the region is not locked. */ | |
79 | req->wb_page = page; | |
80 | atomic_set(&req->wb_complete, 0); | |
81 | req->wb_index = page->index; | |
82 | page_cache_get(page); | |
cd52ed35 TM |
83 | BUG_ON(PagePrivate(page)); |
84 | BUG_ON(!PageLocked(page)); | |
85 | BUG_ON(page->mapping->host != inode); | |
1da177e4 LT |
86 | req->wb_offset = offset; |
87 | req->wb_pgbase = offset; | |
88 | req->wb_bytes = count; | |
89 | atomic_set(&req->wb_count, 1); | |
90 | req->wb_context = get_nfs_open_context(ctx); | |
91 | ||
92 | return req; | |
93 | } | |
94 | ||
95 | /** | |
96 | * nfs_unlock_request - Unlock request and wake up sleepers. | |
97 | * @req: | |
98 | */ | |
99 | void nfs_unlock_request(struct nfs_page *req) | |
100 | { | |
101 | if (!NFS_WBACK_BUSY(req)) { | |
102 | printk(KERN_ERR "NFS: Invalid unlock attempted\n"); | |
103 | BUG(); | |
104 | } | |
105 | smp_mb__before_clear_bit(); | |
106 | clear_bit(PG_BUSY, &req->wb_flags); | |
107 | smp_mb__after_clear_bit(); | |
464a98bd | 108 | wake_up_bit(&req->wb_flags, PG_BUSY); |
1da177e4 LT |
109 | nfs_release_request(req); |
110 | } | |
111 | ||
c6a556b8 TM |
112 | /** |
113 | * nfs_set_page_writeback_locked - Lock a request for writeback | |
114 | * @req: | |
115 | */ | |
116 | int nfs_set_page_writeback_locked(struct nfs_page *req) | |
117 | { | |
118 | struct nfs_inode *nfsi = NFS_I(req->wb_context->dentry->d_inode); | |
119 | ||
120 | if (!nfs_lock_request(req)) | |
121 | return 0; | |
122 | radix_tree_tag_set(&nfsi->nfs_page_tree, req->wb_index, NFS_PAGE_TAG_WRITEBACK); | |
123 | return 1; | |
124 | } | |
125 | ||
126 | /** | |
127 | * nfs_clear_page_writeback - Unlock request and wake up sleepers | |
128 | */ | |
129 | void nfs_clear_page_writeback(struct nfs_page *req) | |
130 | { | |
131 | struct nfs_inode *nfsi = NFS_I(req->wb_context->dentry->d_inode); | |
132 | ||
deb7d638 TM |
133 | if (req->wb_page != NULL) { |
134 | spin_lock(&nfsi->req_lock); | |
135 | radix_tree_tag_clear(&nfsi->nfs_page_tree, req->wb_index, NFS_PAGE_TAG_WRITEBACK); | |
136 | spin_unlock(&nfsi->req_lock); | |
137 | } | |
c6a556b8 TM |
138 | nfs_unlock_request(req); |
139 | } | |
140 | ||
1da177e4 LT |
141 | /** |
142 | * nfs_clear_request - Free up all resources allocated to the request | |
143 | * @req: | |
144 | * | |
145 | * Release page resources associated with a write request after it | |
146 | * has completed. | |
147 | */ | |
148 | void nfs_clear_request(struct nfs_page *req) | |
149 | { | |
cd52ed35 TM |
150 | struct page *page = req->wb_page; |
151 | if (page != NULL) { | |
cd52ed35 | 152 | page_cache_release(page); |
1da177e4 LT |
153 | req->wb_page = NULL; |
154 | } | |
155 | } | |
156 | ||
157 | ||
158 | /** | |
159 | * nfs_release_request - Release the count on an NFS read/write request | |
160 | * @req: request to release | |
161 | * | |
162 | * Note: Should never be called with the spinlock held! | |
163 | */ | |
164 | void | |
165 | nfs_release_request(struct nfs_page *req) | |
166 | { | |
167 | if (!atomic_dec_and_test(&req->wb_count)) | |
168 | return; | |
169 | ||
170 | #ifdef NFS_PARANOIA | |
171 | BUG_ON (!list_empty(&req->wb_list)); | |
172 | BUG_ON (NFS_WBACK_BUSY(req)); | |
173 | #endif | |
174 | ||
175 | /* Release struct file or cached credential */ | |
176 | nfs_clear_request(req); | |
177 | put_nfs_open_context(req->wb_context); | |
178 | nfs_page_free(req); | |
179 | } | |
180 | ||
464a98bd TM |
181 | static int nfs_wait_bit_interruptible(void *word) |
182 | { | |
183 | int ret = 0; | |
184 | ||
185 | if (signal_pending(current)) | |
186 | ret = -ERESTARTSYS; | |
187 | else | |
188 | schedule(); | |
189 | return ret; | |
190 | } | |
191 | ||
1da177e4 LT |
192 | /** |
193 | * nfs_wait_on_request - Wait for a request to complete. | |
194 | * @req: request to wait upon. | |
195 | * | |
196 | * Interruptible by signals only if mounted with intr flag. | |
197 | * The user is responsible for holding a count on the request. | |
198 | */ | |
199 | int | |
200 | nfs_wait_on_request(struct nfs_page *req) | |
201 | { | |
464a98bd TM |
202 | struct rpc_clnt *clnt = NFS_CLIENT(req->wb_context->dentry->d_inode); |
203 | sigset_t oldmask; | |
204 | int ret = 0; | |
205 | ||
206 | if (!test_bit(PG_BUSY, &req->wb_flags)) | |
207 | goto out; | |
208 | /* | |
209 | * Note: the call to rpc_clnt_sigmask() suffices to ensure that we | |
210 | * are not interrupted if intr flag is not set | |
211 | */ | |
212 | rpc_clnt_sigmask(clnt, &oldmask); | |
213 | ret = out_of_line_wait_on_bit(&req->wb_flags, PG_BUSY, | |
214 | nfs_wait_bit_interruptible, TASK_INTERRUPTIBLE); | |
215 | rpc_clnt_sigunmask(clnt, &oldmask); | |
216 | out: | |
217 | return ret; | |
1da177e4 LT |
218 | } |
219 | ||
220 | /** | |
d8a5ad75 TM |
221 | * nfs_pageio_init - initialise a page io descriptor |
222 | * @desc: pointer to descriptor | |
bcb71bba TM |
223 | * @inode: pointer to inode |
224 | * @doio: pointer to io function | |
225 | * @bsize: io block size | |
226 | * @io_flags: extra parameters for the io function | |
d8a5ad75 | 227 | */ |
bcb71bba TM |
228 | void nfs_pageio_init(struct nfs_pageio_descriptor *desc, |
229 | struct inode *inode, | |
8d5658c9 | 230 | int (*doio)(struct inode *, struct list_head *, unsigned int, size_t, int), |
84dde76c | 231 | size_t bsize, |
bcb71bba | 232 | int io_flags) |
d8a5ad75 TM |
233 | { |
234 | INIT_LIST_HEAD(&desc->pg_list); | |
bcb71bba | 235 | desc->pg_bytes_written = 0; |
d8a5ad75 TM |
236 | desc->pg_count = 0; |
237 | desc->pg_bsize = bsize; | |
238 | desc->pg_base = 0; | |
bcb71bba TM |
239 | desc->pg_inode = inode; |
240 | desc->pg_doio = doio; | |
241 | desc->pg_ioflags = io_flags; | |
242 | desc->pg_error = 0; | |
d8a5ad75 TM |
243 | } |
244 | ||
245 | /** | |
246 | * nfs_can_coalesce_requests - test two requests for compatibility | |
247 | * @prev: pointer to nfs_page | |
248 | * @req: pointer to nfs_page | |
249 | * | |
250 | * The nfs_page structures 'prev' and 'req' are compared to ensure that the | |
251 | * page data area they describe is contiguous, and that their RPC | |
252 | * credentials, NFSv4 open state, and lockowners are the same. | |
253 | * | |
254 | * Return 'true' if this is the case, else return 'false'. | |
255 | */ | |
256 | static int nfs_can_coalesce_requests(struct nfs_page *prev, | |
257 | struct nfs_page *req) | |
258 | { | |
259 | if (req->wb_context->cred != prev->wb_context->cred) | |
260 | return 0; | |
261 | if (req->wb_context->lockowner != prev->wb_context->lockowner) | |
262 | return 0; | |
263 | if (req->wb_context->state != prev->wb_context->state) | |
264 | return 0; | |
265 | if (req->wb_index != (prev->wb_index + 1)) | |
266 | return 0; | |
267 | if (req->wb_pgbase != 0) | |
268 | return 0; | |
269 | if (prev->wb_pgbase + prev->wb_bytes != PAGE_CACHE_SIZE) | |
270 | return 0; | |
271 | return 1; | |
272 | } | |
273 | ||
274 | /** | |
bcb71bba | 275 | * nfs_pageio_do_add_request - Attempt to coalesce a request into a page list. |
d8a5ad75 TM |
276 | * @desc: destination io descriptor |
277 | * @req: request | |
278 | * | |
279 | * Returns true if the request 'req' was successfully coalesced into the | |
280 | * existing list of pages 'desc'. | |
281 | */ | |
bcb71bba TM |
282 | static int nfs_pageio_do_add_request(struct nfs_pageio_descriptor *desc, |
283 | struct nfs_page *req) | |
d8a5ad75 TM |
284 | { |
285 | size_t newlen = req->wb_bytes; | |
286 | ||
287 | if (desc->pg_count != 0) { | |
288 | struct nfs_page *prev; | |
289 | ||
290 | /* | |
291 | * FIXME: ideally we should be able to coalesce all requests | |
292 | * that are not block boundary aligned, but currently this | |
293 | * is problematic for the case of bsize < PAGE_CACHE_SIZE, | |
294 | * since nfs_flush_multi and nfs_pagein_multi assume you | |
295 | * can have only one struct nfs_page. | |
296 | */ | |
8d5658c9 TM |
297 | if (desc->pg_bsize < PAGE_SIZE) |
298 | return 0; | |
d8a5ad75 | 299 | newlen += desc->pg_count; |
8d5658c9 | 300 | if (newlen > desc->pg_bsize) |
d8a5ad75 TM |
301 | return 0; |
302 | prev = nfs_list_entry(desc->pg_list.prev); | |
303 | if (!nfs_can_coalesce_requests(prev, req)) | |
304 | return 0; | |
305 | } else | |
306 | desc->pg_base = req->wb_pgbase; | |
307 | nfs_list_remove_request(req); | |
308 | nfs_list_add_request(req, &desc->pg_list); | |
309 | desc->pg_count = newlen; | |
310 | return 1; | |
311 | } | |
312 | ||
bcb71bba TM |
313 | /* |
314 | * Helper for nfs_pageio_add_request and nfs_pageio_complete | |
315 | */ | |
316 | static void nfs_pageio_doio(struct nfs_pageio_descriptor *desc) | |
317 | { | |
318 | if (!list_empty(&desc->pg_list)) { | |
319 | int error = desc->pg_doio(desc->pg_inode, | |
320 | &desc->pg_list, | |
8d5658c9 TM |
321 | nfs_page_array_len(desc->pg_base, |
322 | desc->pg_count), | |
bcb71bba TM |
323 | desc->pg_count, |
324 | desc->pg_ioflags); | |
325 | if (error < 0) | |
326 | desc->pg_error = error; | |
327 | else | |
328 | desc->pg_bytes_written += desc->pg_count; | |
329 | } | |
330 | if (list_empty(&desc->pg_list)) { | |
331 | desc->pg_count = 0; | |
332 | desc->pg_base = 0; | |
333 | } | |
334 | } | |
335 | ||
336 | /** | |
337 | * nfs_pageio_add_request - Attempt to coalesce a request into a page list. | |
338 | * @desc: destination io descriptor | |
339 | * @req: request | |
340 | * | |
341 | * Returns true if the request 'req' was successfully coalesced into the | |
342 | * existing list of pages 'desc'. | |
343 | */ | |
8b09bee3 TM |
344 | int nfs_pageio_add_request(struct nfs_pageio_descriptor *desc, |
345 | struct nfs_page *req) | |
bcb71bba TM |
346 | { |
347 | while (!nfs_pageio_do_add_request(desc, req)) { | |
348 | nfs_pageio_doio(desc); | |
349 | if (desc->pg_error < 0) | |
350 | return 0; | |
351 | } | |
352 | return 1; | |
353 | } | |
354 | ||
bcb71bba TM |
355 | /** |
356 | * nfs_pageio_complete - Complete I/O on an nfs_pageio_descriptor | |
357 | * @desc: pointer to io descriptor | |
358 | */ | |
359 | void nfs_pageio_complete(struct nfs_pageio_descriptor *desc) | |
360 | { | |
361 | nfs_pageio_doio(desc); | |
362 | } | |
363 | ||
3da28eb1 | 364 | #define NFS_SCAN_MAXENTRIES 16 |
1da177e4 LT |
365 | /** |
366 | * nfs_scan_list - Scan a list for matching requests | |
d2ccddf0 | 367 | * @nfsi: NFS inode |
1da177e4 LT |
368 | * @head: One of the NFS inode request lists |
369 | * @dst: Destination list | |
370 | * @idx_start: lower bound of page->index to scan | |
371 | * @npages: idx_start + npages sets the upper bound to scan. | |
372 | * | |
373 | * Moves elements from one of the inode request lists. | |
374 | * If the number of requests is set to 0, the entire address_space | |
375 | * starting at index idx_start, is scanned. | |
376 | * The requests are *not* checked to ensure that they form a contiguous set. | |
377 | * You must be holding the inode's req_lock when calling this function | |
378 | */ | |
d2ccddf0 | 379 | int nfs_scan_list(struct nfs_inode *nfsi, struct list_head *head, |
ca52fec1 | 380 | struct list_head *dst, pgoff_t idx_start, |
d2ccddf0 | 381 | unsigned int npages) |
1da177e4 | 382 | { |
d2ccddf0 TM |
383 | struct nfs_page *pgvec[NFS_SCAN_MAXENTRIES]; |
384 | struct nfs_page *req; | |
ca52fec1 | 385 | pgoff_t idx_end; |
d2ccddf0 TM |
386 | int found, i; |
387 | int res; | |
1da177e4 LT |
388 | |
389 | res = 0; | |
390 | if (npages == 0) | |
391 | idx_end = ~0; | |
392 | else | |
393 | idx_end = idx_start + npages - 1; | |
394 | ||
d2ccddf0 TM |
395 | for (;;) { |
396 | found = radix_tree_gang_lookup(&nfsi->nfs_page_tree, | |
397 | (void **)&pgvec[0], idx_start, | |
398 | NFS_SCAN_MAXENTRIES); | |
399 | if (found <= 0) | |
1da177e4 | 400 | break; |
d2ccddf0 TM |
401 | for (i = 0; i < found; i++) { |
402 | req = pgvec[i]; | |
403 | if (req->wb_index > idx_end) | |
404 | goto out; | |
405 | idx_start = req->wb_index + 1; | |
406 | if (req->wb_list_head != head) | |
407 | continue; | |
408 | if (nfs_set_page_writeback_locked(req)) { | |
409 | nfs_list_remove_request(req); | |
410 | nfs_list_add_request(req, dst); | |
411 | res++; | |
412 | } | |
413 | } | |
1da177e4 | 414 | |
1da177e4 | 415 | } |
d2ccddf0 | 416 | out: |
1da177e4 LT |
417 | return res; |
418 | } | |
419 | ||
f7b422b1 | 420 | int __init nfs_init_nfspagecache(void) |
1da177e4 LT |
421 | { |
422 | nfs_page_cachep = kmem_cache_create("nfs_page", | |
423 | sizeof(struct nfs_page), | |
424 | 0, SLAB_HWCACHE_ALIGN, | |
425 | NULL, NULL); | |
426 | if (nfs_page_cachep == NULL) | |
427 | return -ENOMEM; | |
428 | ||
429 | return 0; | |
430 | } | |
431 | ||
266bee88 | 432 | void nfs_destroy_nfspagecache(void) |
1da177e4 | 433 | { |
1a1d92c1 | 434 | kmem_cache_destroy(nfs_page_cachep); |
1da177e4 LT |
435 | } |
436 |