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