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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> | |
e8edc6e0 | 14 | #include <linux/sched.h> |
1da177e4 LT |
15 | #include <linux/sunrpc/clnt.h> |
16 | #include <linux/nfs3.h> | |
17 | #include <linux/nfs4.h> | |
18 | #include <linux/nfs_page.h> | |
19 | #include <linux/nfs_fs.h> | |
20 | #include <linux/nfs_mount.h> | |
21 | ||
8d5658c9 TM |
22 | #include "internal.h" |
23 | ||
e18b890b | 24 | static struct kmem_cache *nfs_page_cachep; |
1da177e4 LT |
25 | |
26 | static inline struct nfs_page * | |
27 | nfs_page_alloc(void) | |
28 | { | |
29 | struct nfs_page *p; | |
e94b1766 | 30 | p = kmem_cache_alloc(nfs_page_cachep, GFP_KERNEL); |
1da177e4 LT |
31 | if (p) { |
32 | memset(p, 0, sizeof(*p)); | |
33 | INIT_LIST_HEAD(&p->wb_list); | |
34 | } | |
35 | return p; | |
36 | } | |
37 | ||
38 | static inline void | |
39 | nfs_page_free(struct nfs_page *p) | |
40 | { | |
41 | kmem_cache_free(nfs_page_cachep, p); | |
42 | } | |
43 | ||
44 | /** | |
45 | * nfs_create_request - Create an NFS read/write request. | |
46 | * @file: file descriptor to use | |
47 | * @inode: inode to which the request is attached | |
48 | * @page: page to write | |
49 | * @offset: starting offset within the page for the write | |
50 | * @count: number of bytes to read/write | |
51 | * | |
52 | * The page must be locked by the caller. This makes sure we never | |
a19b89ca | 53 | * create two different requests for the same page. |
1da177e4 LT |
54 | * User should ensure it is safe to sleep in this function. |
55 | */ | |
56 | struct nfs_page * | |
57 | nfs_create_request(struct nfs_open_context *ctx, struct inode *inode, | |
58 | struct page *page, | |
59 | unsigned int offset, unsigned int count) | |
60 | { | |
1da177e4 LT |
61 | struct nfs_page *req; |
62 | ||
18eb8842 TM |
63 | /* try to allocate the request struct */ |
64 | req = nfs_page_alloc(); | |
65 | if (req == NULL) | |
66 | return ERR_PTR(-ENOMEM); | |
1da177e4 | 67 | |
015f0212 JL |
68 | /* get lock context early so we can deal with alloc failures */ |
69 | req->wb_lock_context = nfs_get_lock_context(ctx); | |
70 | if (req->wb_lock_context == NULL) { | |
71 | nfs_page_free(req); | |
72 | return ERR_PTR(-ENOMEM); | |
73 | } | |
74 | ||
1da177e4 LT |
75 | /* Initialize the request struct. Initially, we assume a |
76 | * long write-back delay. This will be adjusted in | |
77 | * update_nfs_request below if the region is not locked. */ | |
78 | req->wb_page = page; | |
79 | atomic_set(&req->wb_complete, 0); | |
80 | req->wb_index = page->index; | |
81 | page_cache_get(page); | |
cd52ed35 TM |
82 | BUG_ON(PagePrivate(page)); |
83 | BUG_ON(!PageLocked(page)); | |
84 | BUG_ON(page->mapping->host != inode); | |
1da177e4 LT |
85 | req->wb_offset = offset; |
86 | req->wb_pgbase = offset; | |
87 | req->wb_bytes = count; | |
1da177e4 | 88 | req->wb_context = get_nfs_open_context(ctx); |
c03b4024 | 89 | kref_init(&req->wb_kref); |
1da177e4 LT |
90 | return req; |
91 | } | |
92 | ||
93 | /** | |
94 | * nfs_unlock_request - Unlock request and wake up sleepers. | |
95 | * @req: | |
96 | */ | |
97 | void nfs_unlock_request(struct nfs_page *req) | |
98 | { | |
99 | if (!NFS_WBACK_BUSY(req)) { | |
100 | printk(KERN_ERR "NFS: Invalid unlock attempted\n"); | |
101 | BUG(); | |
102 | } | |
103 | smp_mb__before_clear_bit(); | |
104 | clear_bit(PG_BUSY, &req->wb_flags); | |
105 | smp_mb__after_clear_bit(); | |
464a98bd | 106 | wake_up_bit(&req->wb_flags, PG_BUSY); |
1da177e4 LT |
107 | nfs_release_request(req); |
108 | } | |
109 | ||
c6a556b8 | 110 | /** |
9fd367f0 | 111 | * nfs_set_page_tag_locked - Tag a request as locked |
c6a556b8 TM |
112 | * @req: |
113 | */ | |
acee478a | 114 | int nfs_set_page_tag_locked(struct nfs_page *req) |
c6a556b8 | 115 | { |
acee478a | 116 | if (!nfs_lock_request_dontget(req)) |
c6a556b8 | 117 | return 0; |
acee478a | 118 | if (req->wb_page != NULL) |
bb6fbc45 | 119 | radix_tree_tag_set(&NFS_I(req->wb_context->path.dentry->d_inode)->nfs_page_tree, req->wb_index, NFS_PAGE_TAG_LOCKED); |
c6a556b8 TM |
120 | return 1; |
121 | } | |
122 | ||
123 | /** | |
9fd367f0 | 124 | * nfs_clear_page_tag_locked - Clear request tag and wake up sleepers |
c6a556b8 | 125 | */ |
9fd367f0 | 126 | void nfs_clear_page_tag_locked(struct nfs_page *req) |
c6a556b8 | 127 | { |
deb7d638 | 128 | if (req->wb_page != NULL) { |
bb6fbc45 TM |
129 | struct inode *inode = req->wb_context->path.dentry->d_inode; |
130 | struct nfs_inode *nfsi = NFS_I(inode); | |
131 | ||
587142f8 | 132 | spin_lock(&inode->i_lock); |
9fd367f0 | 133 | radix_tree_tag_clear(&nfsi->nfs_page_tree, req->wb_index, NFS_PAGE_TAG_LOCKED); |
acee478a | 134 | nfs_unlock_request(req); |
587142f8 | 135 | spin_unlock(&inode->i_lock); |
acee478a TM |
136 | } else |
137 | nfs_unlock_request(req); | |
c6a556b8 TM |
138 | } |
139 | ||
1da177e4 LT |
140 | /** |
141 | * nfs_clear_request - Free up all resources allocated to the request | |
142 | * @req: | |
143 | * | |
bb6fbc45 TM |
144 | * Release page and open context resources associated with a read/write |
145 | * request after it has completed. | |
1da177e4 LT |
146 | */ |
147 | void nfs_clear_request(struct nfs_page *req) | |
148 | { | |
cd52ed35 | 149 | struct page *page = req->wb_page; |
bb6fbc45 | 150 | struct nfs_open_context *ctx = req->wb_context; |
f11ac8db | 151 | struct nfs_lock_context *l_ctx = req->wb_lock_context; |
bb6fbc45 | 152 | |
cd52ed35 | 153 | if (page != NULL) { |
cd52ed35 | 154 | page_cache_release(page); |
1da177e4 LT |
155 | req->wb_page = NULL; |
156 | } | |
f11ac8db TM |
157 | if (l_ctx != NULL) { |
158 | nfs_put_lock_context(l_ctx); | |
159 | req->wb_lock_context = NULL; | |
160 | } | |
bb6fbc45 TM |
161 | if (ctx != NULL) { |
162 | put_nfs_open_context(ctx); | |
163 | req->wb_context = NULL; | |
164 | } | |
1da177e4 LT |
165 | } |
166 | ||
167 | ||
168 | /** | |
169 | * nfs_release_request - Release the count on an NFS read/write request | |
170 | * @req: request to release | |
171 | * | |
172 | * Note: Should never be called with the spinlock held! | |
173 | */ | |
c03b4024 | 174 | static void nfs_free_request(struct kref *kref) |
1da177e4 | 175 | { |
c03b4024 | 176 | struct nfs_page *req = container_of(kref, struct nfs_page, wb_kref); |
1da177e4 | 177 | |
bb6fbc45 | 178 | /* Release struct file and open context */ |
1da177e4 | 179 | nfs_clear_request(req); |
1da177e4 LT |
180 | nfs_page_free(req); |
181 | } | |
182 | ||
c03b4024 TM |
183 | void nfs_release_request(struct nfs_page *req) |
184 | { | |
185 | kref_put(&req->wb_kref, nfs_free_request); | |
186 | } | |
187 | ||
9f557cd8 TM |
188 | static int nfs_wait_bit_uninterruptible(void *word) |
189 | { | |
190 | io_schedule(); | |
191 | return 0; | |
192 | } | |
193 | ||
1da177e4 LT |
194 | /** |
195 | * nfs_wait_on_request - Wait for a request to complete. | |
196 | * @req: request to wait upon. | |
197 | * | |
150030b7 | 198 | * Interruptible by fatal signals only. |
1da177e4 LT |
199 | * The user is responsible for holding a count on the request. |
200 | */ | |
201 | int | |
202 | nfs_wait_on_request(struct nfs_page *req) | |
203 | { | |
9f557cd8 TM |
204 | return wait_on_bit(&req->wb_flags, PG_BUSY, |
205 | nfs_wait_bit_uninterruptible, | |
206 | TASK_UNINTERRUPTIBLE); | |
1da177e4 LT |
207 | } |
208 | ||
209 | /** | |
d8a5ad75 TM |
210 | * nfs_pageio_init - initialise a page io descriptor |
211 | * @desc: pointer to descriptor | |
bcb71bba TM |
212 | * @inode: pointer to inode |
213 | * @doio: pointer to io function | |
214 | * @bsize: io block size | |
215 | * @io_flags: extra parameters for the io function | |
d8a5ad75 | 216 | */ |
bcb71bba TM |
217 | void nfs_pageio_init(struct nfs_pageio_descriptor *desc, |
218 | struct inode *inode, | |
8d5658c9 | 219 | int (*doio)(struct inode *, struct list_head *, unsigned int, size_t, int), |
84dde76c | 220 | size_t bsize, |
bcb71bba | 221 | int io_flags) |
d8a5ad75 TM |
222 | { |
223 | INIT_LIST_HEAD(&desc->pg_list); | |
bcb71bba | 224 | desc->pg_bytes_written = 0; |
d8a5ad75 TM |
225 | desc->pg_count = 0; |
226 | desc->pg_bsize = bsize; | |
227 | desc->pg_base = 0; | |
bcb71bba TM |
228 | desc->pg_inode = inode; |
229 | desc->pg_doio = doio; | |
230 | desc->pg_ioflags = io_flags; | |
231 | desc->pg_error = 0; | |
d8a5ad75 TM |
232 | } |
233 | ||
234 | /** | |
235 | * nfs_can_coalesce_requests - test two requests for compatibility | |
236 | * @prev: pointer to nfs_page | |
237 | * @req: pointer to nfs_page | |
238 | * | |
239 | * The nfs_page structures 'prev' and 'req' are compared to ensure that the | |
240 | * page data area they describe is contiguous, and that their RPC | |
241 | * credentials, NFSv4 open state, and lockowners are the same. | |
242 | * | |
243 | * Return 'true' if this is the case, else return 'false'. | |
244 | */ | |
245 | static int nfs_can_coalesce_requests(struct nfs_page *prev, | |
246 | struct nfs_page *req) | |
247 | { | |
248 | if (req->wb_context->cred != prev->wb_context->cred) | |
249 | return 0; | |
f11ac8db | 250 | if (req->wb_lock_context->lockowner != prev->wb_lock_context->lockowner) |
d8a5ad75 TM |
251 | return 0; |
252 | if (req->wb_context->state != prev->wb_context->state) | |
253 | return 0; | |
254 | if (req->wb_index != (prev->wb_index + 1)) | |
255 | return 0; | |
256 | if (req->wb_pgbase != 0) | |
257 | return 0; | |
258 | if (prev->wb_pgbase + prev->wb_bytes != PAGE_CACHE_SIZE) | |
259 | return 0; | |
260 | return 1; | |
261 | } | |
262 | ||
263 | /** | |
bcb71bba | 264 | * nfs_pageio_do_add_request - Attempt to coalesce a request into a page list. |
d8a5ad75 TM |
265 | * @desc: destination io descriptor |
266 | * @req: request | |
267 | * | |
268 | * Returns true if the request 'req' was successfully coalesced into the | |
269 | * existing list of pages 'desc'. | |
270 | */ | |
bcb71bba TM |
271 | static int nfs_pageio_do_add_request(struct nfs_pageio_descriptor *desc, |
272 | struct nfs_page *req) | |
d8a5ad75 TM |
273 | { |
274 | size_t newlen = req->wb_bytes; | |
275 | ||
276 | if (desc->pg_count != 0) { | |
277 | struct nfs_page *prev; | |
278 | ||
279 | /* | |
280 | * FIXME: ideally we should be able to coalesce all requests | |
281 | * that are not block boundary aligned, but currently this | |
282 | * is problematic for the case of bsize < PAGE_CACHE_SIZE, | |
283 | * since nfs_flush_multi and nfs_pagein_multi assume you | |
284 | * can have only one struct nfs_page. | |
285 | */ | |
8d5658c9 TM |
286 | if (desc->pg_bsize < PAGE_SIZE) |
287 | return 0; | |
d8a5ad75 | 288 | newlen += desc->pg_count; |
8d5658c9 | 289 | if (newlen > desc->pg_bsize) |
d8a5ad75 TM |
290 | return 0; |
291 | prev = nfs_list_entry(desc->pg_list.prev); | |
292 | if (!nfs_can_coalesce_requests(prev, req)) | |
293 | return 0; | |
294 | } else | |
295 | desc->pg_base = req->wb_pgbase; | |
296 | nfs_list_remove_request(req); | |
297 | nfs_list_add_request(req, &desc->pg_list); | |
298 | desc->pg_count = newlen; | |
299 | return 1; | |
300 | } | |
301 | ||
bcb71bba TM |
302 | /* |
303 | * Helper for nfs_pageio_add_request and nfs_pageio_complete | |
304 | */ | |
305 | static void nfs_pageio_doio(struct nfs_pageio_descriptor *desc) | |
306 | { | |
307 | if (!list_empty(&desc->pg_list)) { | |
308 | int error = desc->pg_doio(desc->pg_inode, | |
309 | &desc->pg_list, | |
8d5658c9 TM |
310 | nfs_page_array_len(desc->pg_base, |
311 | desc->pg_count), | |
bcb71bba TM |
312 | desc->pg_count, |
313 | desc->pg_ioflags); | |
314 | if (error < 0) | |
315 | desc->pg_error = error; | |
316 | else | |
317 | desc->pg_bytes_written += desc->pg_count; | |
318 | } | |
319 | if (list_empty(&desc->pg_list)) { | |
320 | desc->pg_count = 0; | |
321 | desc->pg_base = 0; | |
322 | } | |
323 | } | |
324 | ||
325 | /** | |
326 | * nfs_pageio_add_request - Attempt to coalesce a request into a page list. | |
327 | * @desc: destination io descriptor | |
328 | * @req: request | |
329 | * | |
330 | * Returns true if the request 'req' was successfully coalesced into the | |
331 | * existing list of pages 'desc'. | |
332 | */ | |
8b09bee3 TM |
333 | int nfs_pageio_add_request(struct nfs_pageio_descriptor *desc, |
334 | struct nfs_page *req) | |
bcb71bba TM |
335 | { |
336 | while (!nfs_pageio_do_add_request(desc, req)) { | |
337 | nfs_pageio_doio(desc); | |
338 | if (desc->pg_error < 0) | |
339 | return 0; | |
340 | } | |
341 | return 1; | |
342 | } | |
343 | ||
bcb71bba TM |
344 | /** |
345 | * nfs_pageio_complete - Complete I/O on an nfs_pageio_descriptor | |
346 | * @desc: pointer to io descriptor | |
347 | */ | |
348 | void nfs_pageio_complete(struct nfs_pageio_descriptor *desc) | |
349 | { | |
350 | nfs_pageio_doio(desc); | |
351 | } | |
352 | ||
7fe7f848 TM |
353 | /** |
354 | * nfs_pageio_cond_complete - Conditional I/O completion | |
355 | * @desc: pointer to io descriptor | |
356 | * @index: page index | |
357 | * | |
358 | * It is important to ensure that processes don't try to take locks | |
359 | * on non-contiguous ranges of pages as that might deadlock. This | |
360 | * function should be called before attempting to wait on a locked | |
361 | * nfs_page. It will complete the I/O if the page index 'index' | |
362 | * is not contiguous with the existing list of pages in 'desc'. | |
363 | */ | |
364 | void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *desc, pgoff_t index) | |
365 | { | |
366 | if (!list_empty(&desc->pg_list)) { | |
367 | struct nfs_page *prev = nfs_list_entry(desc->pg_list.prev); | |
368 | if (index != prev->wb_index + 1) | |
369 | nfs_pageio_doio(desc); | |
370 | } | |
371 | } | |
372 | ||
3da28eb1 | 373 | #define NFS_SCAN_MAXENTRIES 16 |
1da177e4 LT |
374 | /** |
375 | * nfs_scan_list - Scan a list for matching requests | |
d2ccddf0 | 376 | * @nfsi: NFS inode |
1da177e4 LT |
377 | * @dst: Destination list |
378 | * @idx_start: lower bound of page->index to scan | |
379 | * @npages: idx_start + npages sets the upper bound to scan. | |
5c369683 | 380 | * @tag: tag to scan for |
1da177e4 LT |
381 | * |
382 | * Moves elements from one of the inode request lists. | |
383 | * If the number of requests is set to 0, the entire address_space | |
384 | * starting at index idx_start, is scanned. | |
385 | * The requests are *not* checked to ensure that they form a contiguous set. | |
587142f8 | 386 | * You must be holding the inode's i_lock when calling this function |
1da177e4 | 387 | */ |
5c369683 | 388 | int nfs_scan_list(struct nfs_inode *nfsi, |
ca52fec1 | 389 | struct list_head *dst, pgoff_t idx_start, |
5c369683 | 390 | unsigned int npages, int tag) |
1da177e4 | 391 | { |
d2ccddf0 TM |
392 | struct nfs_page *pgvec[NFS_SCAN_MAXENTRIES]; |
393 | struct nfs_page *req; | |
ca52fec1 | 394 | pgoff_t idx_end; |
d2ccddf0 TM |
395 | int found, i; |
396 | int res; | |
1da177e4 LT |
397 | |
398 | res = 0; | |
399 | if (npages == 0) | |
400 | idx_end = ~0; | |
401 | else | |
402 | idx_end = idx_start + npages - 1; | |
403 | ||
d2ccddf0 | 404 | for (;;) { |
5c369683 | 405 | found = radix_tree_gang_lookup_tag(&nfsi->nfs_page_tree, |
d2ccddf0 | 406 | (void **)&pgvec[0], idx_start, |
5c369683 | 407 | NFS_SCAN_MAXENTRIES, tag); |
d2ccddf0 | 408 | if (found <= 0) |
1da177e4 | 409 | break; |
d2ccddf0 TM |
410 | for (i = 0; i < found; i++) { |
411 | req = pgvec[i]; | |
412 | if (req->wb_index > idx_end) | |
413 | goto out; | |
414 | idx_start = req->wb_index + 1; | |
9fd367f0 | 415 | if (nfs_set_page_tag_locked(req)) { |
acee478a | 416 | kref_get(&req->wb_kref); |
d2ccddf0 | 417 | nfs_list_remove_request(req); |
5c369683 TM |
418 | radix_tree_tag_clear(&nfsi->nfs_page_tree, |
419 | req->wb_index, tag); | |
d2ccddf0 TM |
420 | nfs_list_add_request(req, dst); |
421 | res++; | |
dce34ce2 TM |
422 | if (res == INT_MAX) |
423 | goto out; | |
d2ccddf0 TM |
424 | } |
425 | } | |
edc05fc1 | 426 | /* for latency reduction */ |
587142f8 | 427 | cond_resched_lock(&nfsi->vfs_inode.i_lock); |
1da177e4 | 428 | } |
d2ccddf0 | 429 | out: |
1da177e4 LT |
430 | return res; |
431 | } | |
432 | ||
f7b422b1 | 433 | int __init nfs_init_nfspagecache(void) |
1da177e4 LT |
434 | { |
435 | nfs_page_cachep = kmem_cache_create("nfs_page", | |
436 | sizeof(struct nfs_page), | |
437 | 0, SLAB_HWCACHE_ALIGN, | |
20c2df83 | 438 | NULL); |
1da177e4 LT |
439 | if (nfs_page_cachep == NULL) |
440 | return -ENOMEM; | |
441 | ||
442 | return 0; | |
443 | } | |
444 | ||
266bee88 | 445 | void nfs_destroy_nfspagecache(void) |
1da177e4 | 446 | { |
1a1d92c1 | 447 | kmem_cache_destroy(nfs_page_cachep); |
1da177e4 LT |
448 | } |
449 |