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1f327613 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
147b31cf | 2 | /* |
147b31cf EVH |
3 | * This file contians vfs address (mmap) ops for 9P2000. |
4 | * | |
5 | * Copyright (C) 2005 by Eric Van Hensbergen <ericvh@gmail.com> | |
6 | * Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov> | |
147b31cf EVH |
7 | */ |
8 | ||
9 | #include <linux/module.h> | |
10 | #include <linux/errno.h> | |
11 | #include <linux/fs.h> | |
12 | #include <linux/file.h> | |
13 | #include <linux/stat.h> | |
14 | #include <linux/string.h> | |
147b31cf | 15 | #include <linux/inet.h> |
147b31cf EVH |
16 | #include <linux/pagemap.h> |
17 | #include <linux/idr.h> | |
e8edc6e0 | 18 | #include <linux/sched.h> |
e2e40f2c | 19 | #include <linux/uio.h> |
eb497943 | 20 | #include <linux/netfs.h> |
bd238fb4 LI |
21 | #include <net/9p/9p.h> |
22 | #include <net/9p/client.h> | |
147b31cf | 23 | |
147b31cf | 24 | #include "v9fs.h" |
147b31cf | 25 | #include "v9fs_vfs.h" |
60e78d2c | 26 | #include "cache.h" |
7263cebe | 27 | #include "fid.h" |
147b31cf EVH |
28 | |
29 | /** | |
eb497943 DH |
30 | * v9fs_req_issue_op - Issue a read from 9P |
31 | * @subreq: The read to make | |
147b31cf | 32 | */ |
eb497943 | 33 | static void v9fs_req_issue_op(struct netfs_read_subrequest *subreq) |
147b31cf | 34 | { |
eb497943 DH |
35 | struct netfs_read_request *rreq = subreq->rreq; |
36 | struct p9_fid *fid = rreq->netfs_priv; | |
e1200fe6 | 37 | struct iov_iter to; |
eb497943 DH |
38 | loff_t pos = subreq->start + subreq->transferred; |
39 | size_t len = subreq->len - subreq->transferred; | |
40 | int total, err; | |
e03abc0c | 41 | |
eb497943 | 42 | iov_iter_xarray(&to, READ, &rreq->mapping->i_pages, pos, len); |
60e78d2c | 43 | |
eb497943 DH |
44 | total = p9_client_read(fid, pos, &to, &err); |
45 | netfs_subreq_terminated(subreq, err ?: total, false); | |
46 | } | |
60e78d2c | 47 | |
eb497943 DH |
48 | /** |
49 | * v9fs_init_rreq - Initialise a read request | |
50 | * @rreq: The read request | |
51 | * @file: The file being read from | |
52 | */ | |
53 | static void v9fs_init_rreq(struct netfs_read_request *rreq, struct file *file) | |
54 | { | |
55 | struct p9_fid *fid = file->private_data; | |
60e78d2c | 56 | |
eb497943 DH |
57 | refcount_inc(&fid->count); |
58 | rreq->netfs_priv = fid; | |
59 | } | |
147b31cf | 60 | |
eb497943 DH |
61 | /** |
62 | * v9fs_req_cleanup - Cleanup request initialized by v9fs_init_rreq | |
63 | * @mapping: unused mapping of request to cleanup | |
64 | * @priv: private data to cleanup, a fid, guaranted non-null. | |
65 | */ | |
66 | static void v9fs_req_cleanup(struct address_space *mapping, void *priv) | |
67 | { | |
68 | struct p9_fid *fid = priv; | |
147b31cf | 69 | |
eb497943 DH |
70 | p9_client_clunk(fid); |
71 | } | |
60e78d2c | 72 | |
eb497943 DH |
73 | /** |
74 | * v9fs_is_cache_enabled - Determine if caching is enabled for an inode | |
75 | * @inode: The inode to check | |
76 | */ | |
77 | static bool v9fs_is_cache_enabled(struct inode *inode) | |
78 | { | |
24e42e32 DH |
79 | struct fscache_cookie *cookie = v9fs_inode_cookie(V9FS_I(inode)); |
80 | ||
81 | return fscache_cookie_enabled(cookie) && cookie->cache_priv; | |
eb497943 DH |
82 | } |
83 | ||
84 | /** | |
85 | * v9fs_begin_cache_operation - Begin a cache operation for a read | |
86 | * @rreq: The read request | |
87 | */ | |
88 | static int v9fs_begin_cache_operation(struct netfs_read_request *rreq) | |
89 | { | |
2cee6fbb | 90 | #ifdef CONFIG_9P_FSCACHE |
eb497943 DH |
91 | struct fscache_cookie *cookie = v9fs_inode_cookie(V9FS_I(rreq->inode)); |
92 | ||
24e42e32 | 93 | return fscache_begin_read_operation(&rreq->cache_resources, cookie); |
2cee6fbb DH |
94 | #else |
95 | return -ENOBUFS; | |
96 | #endif | |
147b31cf EVH |
97 | } |
98 | ||
eb497943 DH |
99 | static const struct netfs_read_request_ops v9fs_req_ops = { |
100 | .init_rreq = v9fs_init_rreq, | |
101 | .is_cache_enabled = v9fs_is_cache_enabled, | |
102 | .begin_cache_operation = v9fs_begin_cache_operation, | |
103 | .issue_op = v9fs_req_issue_op, | |
104 | .cleanup = v9fs_req_cleanup, | |
105 | }; | |
106 | ||
7263cebe AK |
107 | /** |
108 | * v9fs_vfs_readpage - read an entire page in from 9P | |
eb497943 | 109 | * @file: file being read |
7263cebe AK |
110 | * @page: structure to page |
111 | * | |
112 | */ | |
eb497943 | 113 | static int v9fs_vfs_readpage(struct file *file, struct page *page) |
7263cebe | 114 | { |
78525c74 DH |
115 | struct folio *folio = page_folio(page); |
116 | ||
117 | return netfs_readpage(file, folio, &v9fs_req_ops, NULL); | |
7263cebe AK |
118 | } |
119 | ||
60e78d2c | 120 | /** |
eb497943 DH |
121 | * v9fs_vfs_readahead - read a set of pages from 9P |
122 | * @ractl: The readahead parameters | |
60e78d2c | 123 | */ |
eb497943 | 124 | static void v9fs_vfs_readahead(struct readahead_control *ractl) |
60e78d2c | 125 | { |
eb497943 | 126 | netfs_readahead(ractl, &v9fs_req_ops, NULL); |
60e78d2c AK |
127 | } |
128 | ||
129 | /** | |
130 | * v9fs_release_page - release the private state associated with a page | |
bc868036 DH |
131 | * @page: The page to be released |
132 | * @gfp: The caller's allocation restrictions | |
60e78d2c AK |
133 | * |
134 | * Returns 1 if the page can be released, false otherwise. | |
135 | */ | |
136 | ||
137 | static int v9fs_release_page(struct page *page, gfp_t gfp) | |
138 | { | |
78525c74 | 139 | struct folio *folio = page_folio(page); |
93c84614 | 140 | struct inode *inode = folio_inode(folio); |
78525c74 DH |
141 | |
142 | if (folio_test_private(folio)) | |
60e78d2c | 143 | return 0; |
eb497943 | 144 | #ifdef CONFIG_9P_FSCACHE |
78525c74 | 145 | if (folio_test_fscache(folio)) { |
24e42e32 | 146 | if (!gfpflags_allow_blocking(gfp) || !(gfp & __GFP_FS)) |
eb497943 | 147 | return 0; |
78525c74 | 148 | folio_wait_fscache(folio); |
eb497943 DH |
149 | } |
150 | #endif | |
93c84614 | 151 | fscache_note_page_release(v9fs_inode_cookie(V9FS_I(inode))); |
eb497943 | 152 | return 1; |
60e78d2c AK |
153 | } |
154 | ||
155 | /** | |
156 | * v9fs_invalidate_page - Invalidate a page completely or partially | |
bc868036 DH |
157 | * @page: The page to be invalidated |
158 | * @offset: offset of the invalidated region | |
159 | * @length: length of the invalidated region | |
60e78d2c AK |
160 | */ |
161 | ||
d47992f8 LC |
162 | static void v9fs_invalidate_page(struct page *page, unsigned int offset, |
163 | unsigned int length) | |
60e78d2c | 164 | { |
78525c74 DH |
165 | struct folio *folio = page_folio(page); |
166 | ||
167 | folio_wait_fscache(folio); | |
60e78d2c AK |
168 | } |
169 | ||
93c84614 DH |
170 | static void v9fs_write_to_cache_done(void *priv, ssize_t transferred_or_error, |
171 | bool was_async) | |
172 | { | |
173 | struct v9fs_inode *v9inode = priv; | |
174 | __le32 version; | |
175 | ||
176 | if (IS_ERR_VALUE(transferred_or_error) && | |
177 | transferred_or_error != -ENOBUFS) { | |
178 | version = cpu_to_le32(v9inode->qid.version); | |
179 | fscache_invalidate(v9fs_inode_cookie(v9inode), &version, | |
180 | i_size_read(&v9inode->vfs_inode), 0); | |
181 | } | |
182 | } | |
183 | ||
78525c74 | 184 | static int v9fs_vfs_write_folio_locked(struct folio *folio) |
7263cebe | 185 | { |
78525c74 | 186 | struct inode *inode = folio_inode(folio); |
371098c6 | 187 | struct v9fs_inode *v9inode = V9FS_I(inode); |
93c84614 | 188 | struct fscache_cookie *cookie = v9fs_inode_cookie(v9inode); |
78525c74 DH |
189 | loff_t start = folio_pos(folio); |
190 | loff_t i_size = i_size_read(inode); | |
371098c6 | 191 | struct iov_iter from; |
78525c74 DH |
192 | size_t len = folio_size(folio); |
193 | int err; | |
194 | ||
195 | if (start >= i_size) | |
196 | return 0; /* Simultaneous truncation occurred */ | |
7263cebe | 197 | |
78525c74 | 198 | len = min_t(loff_t, i_size - start, len); |
7263cebe | 199 | |
78525c74 | 200 | iov_iter_xarray(&from, WRITE, &folio_mapping(folio)->i_pages, start, len); |
7263cebe | 201 | |
6b39f6d2 AK |
202 | /* We should have writeback_fid always set */ |
203 | BUG_ON(!v9inode->writeback_fid); | |
7263cebe | 204 | |
93c84614 | 205 | folio_wait_fscache(folio); |
78525c74 | 206 | folio_start_writeback(folio); |
371098c6 | 207 | |
eb497943 | 208 | p9_client_write(v9inode->writeback_fid, start, &from, &err); |
7263cebe | 209 | |
93c84614 DH |
210 | if (err == 0 && |
211 | fscache_cookie_enabled(cookie) && | |
212 | test_bit(FSCACHE_COOKIE_IS_CACHING, &cookie->flags)) { | |
213 | folio_start_fscache(folio); | |
214 | fscache_write_to_cache(v9fs_inode_cookie(v9inode), | |
215 | folio_mapping(folio), start, len, i_size, | |
216 | v9fs_write_to_cache_done, v9inode, | |
217 | true); | |
218 | } | |
219 | ||
78525c74 | 220 | folio_end_writeback(folio); |
371098c6 | 221 | return err; |
7263cebe AK |
222 | } |
223 | ||
224 | static int v9fs_vfs_writepage(struct page *page, struct writeback_control *wbc) | |
225 | { | |
78525c74 | 226 | struct folio *folio = page_folio(page); |
7263cebe AK |
227 | int retval; |
228 | ||
78525c74 | 229 | p9_debug(P9_DEBUG_VFS, "folio %p\n", folio); |
fb89b45c | 230 | |
78525c74 | 231 | retval = v9fs_vfs_write_folio_locked(folio); |
7263cebe AK |
232 | if (retval < 0) { |
233 | if (retval == -EAGAIN) { | |
78525c74 | 234 | folio_redirty_for_writepage(wbc, folio); |
7263cebe AK |
235 | retval = 0; |
236 | } else { | |
78525c74 | 237 | mapping_set_error(folio_mapping(folio), retval); |
7263cebe AK |
238 | } |
239 | } else | |
240 | retval = 0; | |
241 | ||
78525c74 | 242 | folio_unlock(folio); |
7263cebe AK |
243 | return retval; |
244 | } | |
245 | ||
60e78d2c AK |
246 | /** |
247 | * v9fs_launder_page - Writeback a dirty page | |
bc868036 DH |
248 | * @page: The page to be cleaned up |
249 | * | |
60e78d2c AK |
250 | * Returns 0 on success. |
251 | */ | |
252 | ||
253 | static int v9fs_launder_page(struct page *page) | |
254 | { | |
78525c74 | 255 | struct folio *folio = page_folio(page); |
7263cebe | 256 | int retval; |
7263cebe | 257 | |
78525c74 DH |
258 | if (folio_clear_dirty_for_io(folio)) { |
259 | retval = v9fs_vfs_write_folio_locked(folio); | |
7263cebe AK |
260 | if (retval) |
261 | return retval; | |
262 | } | |
78525c74 | 263 | folio_wait_fscache(folio); |
60e78d2c AK |
264 | return 0; |
265 | } | |
266 | ||
3e24ad2f | 267 | /** |
268 | * v9fs_direct_IO - 9P address space operation for direct I/O | |
3e24ad2f | 269 | * @iocb: target I/O control block |
bc868036 | 270 | * @iter: The data/buffer to use |
3e24ad2f | 271 | * |
272 | * The presence of v9fs_direct_IO() in the address space ops vector | |
273 | * allowes open() O_DIRECT flags which would have failed otherwise. | |
274 | * | |
275 | * In the non-cached mode, we shunt off direct read and write requests before | |
276 | * the VFS gets them, so this method should never be called. | |
277 | * | |
278 | * Direct IO is not 'yet' supported in the cached mode. Hence when | |
279 | * this routine is called through generic_file_aio_read(), the read/write fails | |
280 | * with an error. | |
281 | * | |
282 | */ | |
e959b549 | 283 | static ssize_t |
c8b8e32d | 284 | v9fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter) |
3e24ad2f | 285 | { |
9565a544 | 286 | struct file *file = iocb->ki_filp; |
c8b8e32d | 287 | loff_t pos = iocb->ki_pos; |
42b1ab97 AV |
288 | ssize_t n; |
289 | int err = 0; | |
6e195b0f | 290 | |
6f673763 | 291 | if (iov_iter_rw(iter) == WRITE) { |
42b1ab97 AV |
292 | n = p9_client_write(file->private_data, pos, iter, &err); |
293 | if (n) { | |
9565a544 AV |
294 | struct inode *inode = file_inode(file); |
295 | loff_t i_size = i_size_read(inode); | |
6e195b0f | 296 | |
42b1ab97 AV |
297 | if (pos + n > i_size) |
298 | inode_add_bytes(inode, pos + n - i_size); | |
9565a544 | 299 | } |
42b1ab97 AV |
300 | } else { |
301 | n = p9_client_read(file->private_data, pos, iter, &err); | |
9565a544 | 302 | } |
42b1ab97 | 303 | return n ? n : err; |
3e24ad2f | 304 | } |
7263cebe AK |
305 | |
306 | static int v9fs_write_begin(struct file *filp, struct address_space *mapping, | |
6e195b0f | 307 | loff_t pos, unsigned int len, unsigned int flags, |
78525c74 | 308 | struct page **subpagep, void **fsdata) |
7263cebe | 309 | { |
eb497943 | 310 | int retval; |
78525c74 | 311 | struct folio *folio; |
eb497943 | 312 | struct v9fs_inode *v9inode = V9FS_I(mapping->host); |
fb89b45c DM |
313 | |
314 | p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping); | |
315 | ||
6b39f6d2 | 316 | BUG_ON(!v9inode->writeback_fid); |
7263cebe | 317 | |
eb497943 DH |
318 | /* Prefetch area to be written into the cache if we're caching this |
319 | * file. We need to do this before we get a lock on the page in case | |
320 | * there's more than one writer competing for the same cache block. | |
321 | */ | |
78525c74 | 322 | retval = netfs_write_begin(filp, mapping, pos, len, flags, &folio, fsdata, |
eb497943 DH |
323 | &v9fs_req_ops, NULL); |
324 | if (retval < 0) | |
325 | return retval; | |
7263cebe | 326 | |
78525c74 | 327 | *subpagep = &folio->page; |
7263cebe AK |
328 | return retval; |
329 | } | |
330 | ||
331 | static int v9fs_write_end(struct file *filp, struct address_space *mapping, | |
6e195b0f | 332 | loff_t pos, unsigned int len, unsigned int copied, |
78525c74 | 333 | struct page *subpage, void *fsdata) |
7263cebe AK |
334 | { |
335 | loff_t last_pos = pos + copied; | |
78525c74 DH |
336 | struct folio *folio = page_folio(subpage); |
337 | struct inode *inode = mapping->host; | |
93c84614 | 338 | struct v9fs_inode *v9inode = V9FS_I(inode); |
7263cebe | 339 | |
fb89b45c DM |
340 | p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping); |
341 | ||
78525c74 | 342 | if (!folio_test_uptodate(folio)) { |
56ae414e AL |
343 | if (unlikely(copied < len)) { |
344 | copied = 0; | |
345 | goto out; | |
56ae414e | 346 | } |
eb497943 | 347 | |
78525c74 | 348 | folio_mark_uptodate(folio); |
7263cebe | 349 | } |
eb497943 | 350 | |
7263cebe AK |
351 | /* |
352 | * No need to use i_size_read() here, the i_size | |
353 | * cannot change under us because we hold the i_mutex. | |
354 | */ | |
355 | if (last_pos > inode->i_size) { | |
356 | inode_add_bytes(inode, last_pos - inode->i_size); | |
357 | i_size_write(inode, last_pos); | |
93c84614 | 358 | fscache_update_cookie(v9fs_inode_cookie(v9inode), NULL, &last_pos); |
7263cebe | 359 | } |
78525c74 | 360 | folio_mark_dirty(folio); |
77469c3f | 361 | out: |
78525c74 DH |
362 | folio_unlock(folio); |
363 | folio_put(folio); | |
7263cebe AK |
364 | |
365 | return copied; | |
366 | } | |
367 | ||
93c84614 DH |
368 | #ifdef CONFIG_9P_FSCACHE |
369 | /* | |
370 | * Mark a page as having been made dirty and thus needing writeback. We also | |
371 | * need to pin the cache object to write back to. | |
372 | */ | |
373 | static int v9fs_set_page_dirty(struct page *page) | |
374 | { | |
375 | struct v9fs_inode *v9inode = V9FS_I(page->mapping->host); | |
376 | ||
377 | return fscache_set_page_dirty(page, v9fs_inode_cookie(v9inode)); | |
378 | } | |
379 | #else | |
380 | #define v9fs_set_page_dirty __set_page_dirty_nobuffers | |
381 | #endif | |
7263cebe | 382 | |
f5e54d6e | 383 | const struct address_space_operations v9fs_addr_operations = { |
7263cebe | 384 | .readpage = v9fs_vfs_readpage, |
eb497943 | 385 | .readahead = v9fs_vfs_readahead, |
93c84614 | 386 | .set_page_dirty = v9fs_set_page_dirty, |
7263cebe AK |
387 | .writepage = v9fs_vfs_writepage, |
388 | .write_begin = v9fs_write_begin, | |
389 | .write_end = v9fs_write_end, | |
390 | .releasepage = v9fs_release_page, | |
391 | .invalidatepage = v9fs_invalidate_page, | |
392 | .launder_page = v9fs_launder_page, | |
393 | .direct_IO = v9fs_direct_IO, | |
147b31cf | 394 | }; |