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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> |
d7bdba1c | 19 | #include <linux/swap.h> |
e2e40f2c | 20 | #include <linux/uio.h> |
eb497943 | 21 | #include <linux/netfs.h> |
bd238fb4 LI |
22 | #include <net/9p/9p.h> |
23 | #include <net/9p/client.h> | |
147b31cf | 24 | |
147b31cf | 25 | #include "v9fs.h" |
147b31cf | 26 | #include "v9fs_vfs.h" |
60e78d2c | 27 | #include "cache.h" |
7263cebe | 28 | #include "fid.h" |
147b31cf EVH |
29 | |
30 | /** | |
f18a3785 | 31 | * v9fs_issue_read - Issue a read from 9P |
eb497943 | 32 | * @subreq: The read to make |
147b31cf | 33 | */ |
f18a3785 | 34 | static void v9fs_issue_read(struct netfs_io_subrequest *subreq) |
147b31cf | 35 | { |
6a19114b | 36 | struct netfs_io_request *rreq = subreq->rreq; |
eb497943 | 37 | struct p9_fid *fid = rreq->netfs_priv; |
e1200fe6 | 38 | struct iov_iter to; |
eb497943 DH |
39 | loff_t pos = subreq->start + subreq->transferred; |
40 | size_t len = subreq->len - subreq->transferred; | |
41 | int total, err; | |
e03abc0c | 42 | |
eb497943 | 43 | iov_iter_xarray(&to, READ, &rreq->mapping->i_pages, pos, len); |
60e78d2c | 44 | |
eb497943 | 45 | total = p9_client_read(fid, pos, &to, &err); |
19d1c326 DM |
46 | |
47 | /* if we just extended the file size, any portion not in | |
48 | * cache won't be on server and is zeroes */ | |
49 | __set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags); | |
50 | ||
eb497943 DH |
51 | netfs_subreq_terminated(subreq, err ?: total, false); |
52 | } | |
60e78d2c | 53 | |
eb497943 | 54 | /** |
6a19114b | 55 | * v9fs_init_request - Initialise a read request |
eb497943 DH |
56 | * @rreq: The read request |
57 | * @file: The file being read from | |
58 | */ | |
2de16041 | 59 | static int v9fs_init_request(struct netfs_io_request *rreq, struct file *file) |
eb497943 DH |
60 | { |
61 | struct p9_fid *fid = file->private_data; | |
60e78d2c | 62 | |
eb497943 DH |
63 | refcount_inc(&fid->count); |
64 | rreq->netfs_priv = fid; | |
2de16041 | 65 | return 0; |
eb497943 | 66 | } |
147b31cf | 67 | |
eb497943 | 68 | /** |
6a19114b | 69 | * v9fs_req_cleanup - Cleanup request initialized by v9fs_init_request |
eb497943 DH |
70 | * @mapping: unused mapping of request to cleanup |
71 | * @priv: private data to cleanup, a fid, guaranted non-null. | |
72 | */ | |
73 | static void v9fs_req_cleanup(struct address_space *mapping, void *priv) | |
74 | { | |
75 | struct p9_fid *fid = priv; | |
147b31cf | 76 | |
eb497943 DH |
77 | p9_client_clunk(fid); |
78 | } | |
60e78d2c | 79 | |
eb497943 DH |
80 | /** |
81 | * v9fs_begin_cache_operation - Begin a cache operation for a read | |
82 | * @rreq: The read request | |
83 | */ | |
6a19114b | 84 | static int v9fs_begin_cache_operation(struct netfs_io_request *rreq) |
eb497943 | 85 | { |
2cee6fbb | 86 | #ifdef CONFIG_9P_FSCACHE |
eb497943 DH |
87 | struct fscache_cookie *cookie = v9fs_inode_cookie(V9FS_I(rreq->inode)); |
88 | ||
24e42e32 | 89 | return fscache_begin_read_operation(&rreq->cache_resources, cookie); |
2cee6fbb DH |
90 | #else |
91 | return -ENOBUFS; | |
92 | #endif | |
147b31cf EVH |
93 | } |
94 | ||
bc899ee1 | 95 | const struct netfs_request_ops v9fs_req_ops = { |
6a19114b | 96 | .init_request = v9fs_init_request, |
eb497943 | 97 | .begin_cache_operation = v9fs_begin_cache_operation, |
f18a3785 | 98 | .issue_read = v9fs_issue_read, |
eb497943 DH |
99 | .cleanup = v9fs_req_cleanup, |
100 | }; | |
101 | ||
60e78d2c AK |
102 | /** |
103 | * v9fs_release_page - release the private state associated with a page | |
bc868036 DH |
104 | * @page: The page to be released |
105 | * @gfp: The caller's allocation restrictions | |
60e78d2c AK |
106 | * |
107 | * Returns 1 if the page can be released, false otherwise. | |
108 | */ | |
109 | ||
110 | static int v9fs_release_page(struct page *page, gfp_t gfp) | |
111 | { | |
78525c74 | 112 | struct folio *folio = page_folio(page); |
93c84614 | 113 | struct inode *inode = folio_inode(folio); |
78525c74 DH |
114 | |
115 | if (folio_test_private(folio)) | |
60e78d2c | 116 | return 0; |
eb497943 | 117 | #ifdef CONFIG_9P_FSCACHE |
78525c74 | 118 | if (folio_test_fscache(folio)) { |
d7bdba1c | 119 | if (current_is_kswapd() || !(gfp & __GFP_FS)) |
eb497943 | 120 | return 0; |
78525c74 | 121 | folio_wait_fscache(folio); |
eb497943 DH |
122 | } |
123 | #endif | |
93c84614 | 124 | fscache_note_page_release(v9fs_inode_cookie(V9FS_I(inode))); |
eb497943 | 125 | return 1; |
60e78d2c AK |
126 | } |
127 | ||
040cdd4b MWO |
128 | static void v9fs_invalidate_folio(struct folio *folio, size_t offset, |
129 | size_t length) | |
60e78d2c | 130 | { |
78525c74 | 131 | folio_wait_fscache(folio); |
60e78d2c AK |
132 | } |
133 | ||
93c84614 DH |
134 | static void v9fs_write_to_cache_done(void *priv, ssize_t transferred_or_error, |
135 | bool was_async) | |
136 | { | |
137 | struct v9fs_inode *v9inode = priv; | |
138 | __le32 version; | |
139 | ||
140 | if (IS_ERR_VALUE(transferred_or_error) && | |
141 | transferred_or_error != -ENOBUFS) { | |
142 | version = cpu_to_le32(v9inode->qid.version); | |
143 | fscache_invalidate(v9fs_inode_cookie(v9inode), &version, | |
144 | i_size_read(&v9inode->vfs_inode), 0); | |
145 | } | |
146 | } | |
147 | ||
78525c74 | 148 | static int v9fs_vfs_write_folio_locked(struct folio *folio) |
7263cebe | 149 | { |
78525c74 | 150 | struct inode *inode = folio_inode(folio); |
371098c6 | 151 | struct v9fs_inode *v9inode = V9FS_I(inode); |
93c84614 | 152 | struct fscache_cookie *cookie = v9fs_inode_cookie(v9inode); |
78525c74 DH |
153 | loff_t start = folio_pos(folio); |
154 | loff_t i_size = i_size_read(inode); | |
371098c6 | 155 | struct iov_iter from; |
78525c74 DH |
156 | size_t len = folio_size(folio); |
157 | int err; | |
158 | ||
159 | if (start >= i_size) | |
160 | return 0; /* Simultaneous truncation occurred */ | |
7263cebe | 161 | |
78525c74 | 162 | len = min_t(loff_t, i_size - start, len); |
7263cebe | 163 | |
78525c74 | 164 | iov_iter_xarray(&from, WRITE, &folio_mapping(folio)->i_pages, start, len); |
7263cebe | 165 | |
6b39f6d2 AK |
166 | /* We should have writeback_fid always set */ |
167 | BUG_ON(!v9inode->writeback_fid); | |
7263cebe | 168 | |
93c84614 | 169 | folio_wait_fscache(folio); |
78525c74 | 170 | folio_start_writeback(folio); |
371098c6 | 171 | |
eb497943 | 172 | p9_client_write(v9inode->writeback_fid, start, &from, &err); |
7263cebe | 173 | |
93c84614 DH |
174 | if (err == 0 && |
175 | fscache_cookie_enabled(cookie) && | |
176 | test_bit(FSCACHE_COOKIE_IS_CACHING, &cookie->flags)) { | |
177 | folio_start_fscache(folio); | |
178 | fscache_write_to_cache(v9fs_inode_cookie(v9inode), | |
179 | folio_mapping(folio), start, len, i_size, | |
180 | v9fs_write_to_cache_done, v9inode, | |
181 | true); | |
182 | } | |
183 | ||
78525c74 | 184 | folio_end_writeback(folio); |
371098c6 | 185 | return err; |
7263cebe AK |
186 | } |
187 | ||
188 | static int v9fs_vfs_writepage(struct page *page, struct writeback_control *wbc) | |
189 | { | |
78525c74 | 190 | struct folio *folio = page_folio(page); |
7263cebe AK |
191 | int retval; |
192 | ||
78525c74 | 193 | p9_debug(P9_DEBUG_VFS, "folio %p\n", folio); |
fb89b45c | 194 | |
78525c74 | 195 | retval = v9fs_vfs_write_folio_locked(folio); |
7263cebe AK |
196 | if (retval < 0) { |
197 | if (retval == -EAGAIN) { | |
78525c74 | 198 | folio_redirty_for_writepage(wbc, folio); |
7263cebe AK |
199 | retval = 0; |
200 | } else { | |
78525c74 | 201 | mapping_set_error(folio_mapping(folio), retval); |
7263cebe AK |
202 | } |
203 | } else | |
204 | retval = 0; | |
205 | ||
78525c74 | 206 | folio_unlock(folio); |
7263cebe AK |
207 | return retval; |
208 | } | |
209 | ||
76dba927 | 210 | static int v9fs_launder_folio(struct folio *folio) |
60e78d2c | 211 | { |
7263cebe | 212 | int retval; |
7263cebe | 213 | |
78525c74 DH |
214 | if (folio_clear_dirty_for_io(folio)) { |
215 | retval = v9fs_vfs_write_folio_locked(folio); | |
7263cebe AK |
216 | if (retval) |
217 | return retval; | |
218 | } | |
78525c74 | 219 | folio_wait_fscache(folio); |
60e78d2c AK |
220 | return 0; |
221 | } | |
222 | ||
3e24ad2f | 223 | /** |
224 | * v9fs_direct_IO - 9P address space operation for direct I/O | |
3e24ad2f | 225 | * @iocb: target I/O control block |
bc868036 | 226 | * @iter: The data/buffer to use |
3e24ad2f | 227 | * |
228 | * The presence of v9fs_direct_IO() in the address space ops vector | |
229 | * allowes open() O_DIRECT flags which would have failed otherwise. | |
230 | * | |
231 | * In the non-cached mode, we shunt off direct read and write requests before | |
232 | * the VFS gets them, so this method should never be called. | |
233 | * | |
234 | * Direct IO is not 'yet' supported in the cached mode. Hence when | |
235 | * this routine is called through generic_file_aio_read(), the read/write fails | |
236 | * with an error. | |
237 | * | |
238 | */ | |
e959b549 | 239 | static ssize_t |
c8b8e32d | 240 | v9fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter) |
3e24ad2f | 241 | { |
9565a544 | 242 | struct file *file = iocb->ki_filp; |
c8b8e32d | 243 | loff_t pos = iocb->ki_pos; |
42b1ab97 AV |
244 | ssize_t n; |
245 | int err = 0; | |
6e195b0f | 246 | |
6f673763 | 247 | if (iov_iter_rw(iter) == WRITE) { |
42b1ab97 AV |
248 | n = p9_client_write(file->private_data, pos, iter, &err); |
249 | if (n) { | |
9565a544 AV |
250 | struct inode *inode = file_inode(file); |
251 | loff_t i_size = i_size_read(inode); | |
6e195b0f | 252 | |
42b1ab97 AV |
253 | if (pos + n > i_size) |
254 | inode_add_bytes(inode, pos + n - i_size); | |
9565a544 | 255 | } |
42b1ab97 AV |
256 | } else { |
257 | n = p9_client_read(file->private_data, pos, iter, &err); | |
9565a544 | 258 | } |
42b1ab97 | 259 | return n ? n : err; |
3e24ad2f | 260 | } |
7263cebe AK |
261 | |
262 | static int v9fs_write_begin(struct file *filp, struct address_space *mapping, | |
9d6b0cd7 | 263 | loff_t pos, unsigned int len, |
78525c74 | 264 | struct page **subpagep, void **fsdata) |
7263cebe | 265 | { |
eb497943 | 266 | int retval; |
78525c74 | 267 | struct folio *folio; |
eb497943 | 268 | struct v9fs_inode *v9inode = V9FS_I(mapping->host); |
fb89b45c DM |
269 | |
270 | p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping); | |
271 | ||
6b39f6d2 | 272 | BUG_ON(!v9inode->writeback_fid); |
7263cebe | 273 | |
eb497943 DH |
274 | /* Prefetch area to be written into the cache if we're caching this |
275 | * file. We need to do this before we get a lock on the page in case | |
276 | * there's more than one writer competing for the same cache block. | |
277 | */ | |
de2a9311 | 278 | retval = netfs_write_begin(filp, mapping, pos, len, &folio, fsdata); |
eb497943 DH |
279 | if (retval < 0) |
280 | return retval; | |
7263cebe | 281 | |
78525c74 | 282 | *subpagep = &folio->page; |
7263cebe AK |
283 | return retval; |
284 | } | |
285 | ||
286 | static int v9fs_write_end(struct file *filp, struct address_space *mapping, | |
6e195b0f | 287 | loff_t pos, unsigned int len, unsigned int copied, |
78525c74 | 288 | struct page *subpage, void *fsdata) |
7263cebe AK |
289 | { |
290 | loff_t last_pos = pos + copied; | |
78525c74 DH |
291 | struct folio *folio = page_folio(subpage); |
292 | struct inode *inode = mapping->host; | |
93c84614 | 293 | struct v9fs_inode *v9inode = V9FS_I(inode); |
7263cebe | 294 | |
fb89b45c DM |
295 | p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping); |
296 | ||
78525c74 | 297 | if (!folio_test_uptodate(folio)) { |
56ae414e AL |
298 | if (unlikely(copied < len)) { |
299 | copied = 0; | |
300 | goto out; | |
56ae414e | 301 | } |
eb497943 | 302 | |
78525c74 | 303 | folio_mark_uptodate(folio); |
7263cebe | 304 | } |
eb497943 | 305 | |
7263cebe AK |
306 | /* |
307 | * No need to use i_size_read() here, the i_size | |
308 | * cannot change under us because we hold the i_mutex. | |
309 | */ | |
310 | if (last_pos > inode->i_size) { | |
311 | inode_add_bytes(inode, last_pos - inode->i_size); | |
312 | i_size_write(inode, last_pos); | |
93c84614 | 313 | fscache_update_cookie(v9fs_inode_cookie(v9inode), NULL, &last_pos); |
7263cebe | 314 | } |
78525c74 | 315 | folio_mark_dirty(folio); |
77469c3f | 316 | out: |
78525c74 DH |
317 | folio_unlock(folio); |
318 | folio_put(folio); | |
7263cebe AK |
319 | |
320 | return copied; | |
321 | } | |
322 | ||
93c84614 DH |
323 | #ifdef CONFIG_9P_FSCACHE |
324 | /* | |
325 | * Mark a page as having been made dirty and thus needing writeback. We also | |
326 | * need to pin the cache object to write back to. | |
327 | */ | |
8fb72b4a | 328 | static bool v9fs_dirty_folio(struct address_space *mapping, struct folio *folio) |
93c84614 | 329 | { |
8fb72b4a | 330 | struct v9fs_inode *v9inode = V9FS_I(mapping->host); |
93c84614 | 331 | |
8fb72b4a | 332 | return fscache_dirty_folio(mapping, folio, v9fs_inode_cookie(v9inode)); |
93c84614 DH |
333 | } |
334 | #else | |
8fb72b4a | 335 | #define v9fs_dirty_folio filemap_dirty_folio |
93c84614 | 336 | #endif |
7263cebe | 337 | |
f5e54d6e | 338 | const struct address_space_operations v9fs_addr_operations = { |
6c62371b | 339 | .read_folio = netfs_read_folio, |
bc899ee1 | 340 | .readahead = netfs_readahead, |
8fb72b4a | 341 | .dirty_folio = v9fs_dirty_folio, |
7263cebe AK |
342 | .writepage = v9fs_vfs_writepage, |
343 | .write_begin = v9fs_write_begin, | |
344 | .write_end = v9fs_write_end, | |
345 | .releasepage = v9fs_release_page, | |
040cdd4b | 346 | .invalidate_folio = v9fs_invalidate_folio, |
76dba927 | 347 | .launder_folio = v9fs_launder_folio, |
7263cebe | 348 | .direct_IO = v9fs_direct_IO, |
147b31cf | 349 | }; |