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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 | 60 | { |
b0017602 DM |
61 | struct inode *inode = file_inode(file); |
62 | struct v9fs_inode *v9inode = V9FS_I(inode); | |
eb497943 | 63 | struct p9_fid *fid = file->private_data; |
60e78d2c | 64 | |
b0017602 DM |
65 | BUG_ON(!fid); |
66 | ||
67 | /* we might need to read from a fid that was opened write-only | |
68 | * for read-modify-write of page cache, use the writeback fid | |
69 | * for that */ | |
70 | if (rreq->origin == NETFS_READ_FOR_WRITE && | |
71 | (fid->mode & O_ACCMODE) == O_WRONLY) { | |
72 | fid = v9inode->writeback_fid; | |
73 | BUG_ON(!fid); | |
74 | } | |
75 | ||
b48dbb99 | 76 | p9_fid_get(fid); |
eb497943 | 77 | rreq->netfs_priv = fid; |
2de16041 | 78 | return 0; |
eb497943 | 79 | } |
147b31cf | 80 | |
eb497943 | 81 | /** |
40a81101 DH |
82 | * v9fs_free_request - Cleanup request initialized by v9fs_init_rreq |
83 | * @rreq: The I/O request to clean up | |
eb497943 | 84 | */ |
40a81101 | 85 | static void v9fs_free_request(struct netfs_io_request *rreq) |
eb497943 | 86 | { |
40a81101 | 87 | struct p9_fid *fid = rreq->netfs_priv; |
147b31cf | 88 | |
b48dbb99 | 89 | p9_fid_put(fid); |
eb497943 | 90 | } |
60e78d2c | 91 | |
eb497943 DH |
92 | /** |
93 | * v9fs_begin_cache_operation - Begin a cache operation for a read | |
94 | * @rreq: The read request | |
95 | */ | |
6a19114b | 96 | static int v9fs_begin_cache_operation(struct netfs_io_request *rreq) |
eb497943 | 97 | { |
2cee6fbb | 98 | #ifdef CONFIG_9P_FSCACHE |
eb497943 DH |
99 | struct fscache_cookie *cookie = v9fs_inode_cookie(V9FS_I(rreq->inode)); |
100 | ||
24e42e32 | 101 | return fscache_begin_read_operation(&rreq->cache_resources, cookie); |
2cee6fbb DH |
102 | #else |
103 | return -ENOBUFS; | |
104 | #endif | |
147b31cf EVH |
105 | } |
106 | ||
bc899ee1 | 107 | const struct netfs_request_ops v9fs_req_ops = { |
6a19114b | 108 | .init_request = v9fs_init_request, |
40a81101 | 109 | .free_request = v9fs_free_request, |
eb497943 | 110 | .begin_cache_operation = v9fs_begin_cache_operation, |
f18a3785 | 111 | .issue_read = v9fs_issue_read, |
eb497943 DH |
112 | }; |
113 | ||
60e78d2c | 114 | /** |
a26d3411 MWO |
115 | * v9fs_release_folio - release the private state associated with a folio |
116 | * @folio: The folio to be released | |
bc868036 | 117 | * @gfp: The caller's allocation restrictions |
60e78d2c | 118 | * |
a26d3411 | 119 | * Returns true if the page can be released, false otherwise. |
60e78d2c AK |
120 | */ |
121 | ||
a26d3411 | 122 | static bool v9fs_release_folio(struct folio *folio, gfp_t gfp) |
60e78d2c | 123 | { |
93c84614 | 124 | struct inode *inode = folio_inode(folio); |
78525c74 DH |
125 | |
126 | if (folio_test_private(folio)) | |
a26d3411 | 127 | return false; |
eb497943 | 128 | #ifdef CONFIG_9P_FSCACHE |
78525c74 | 129 | if (folio_test_fscache(folio)) { |
d7bdba1c | 130 | if (current_is_kswapd() || !(gfp & __GFP_FS)) |
a26d3411 | 131 | return false; |
78525c74 | 132 | folio_wait_fscache(folio); |
eb497943 DH |
133 | } |
134 | #endif | |
93c84614 | 135 | fscache_note_page_release(v9fs_inode_cookie(V9FS_I(inode))); |
a26d3411 | 136 | return true; |
60e78d2c AK |
137 | } |
138 | ||
040cdd4b MWO |
139 | static void v9fs_invalidate_folio(struct folio *folio, size_t offset, |
140 | size_t length) | |
60e78d2c | 141 | { |
78525c74 | 142 | folio_wait_fscache(folio); |
60e78d2c AK |
143 | } |
144 | ||
93c84614 DH |
145 | static void v9fs_write_to_cache_done(void *priv, ssize_t transferred_or_error, |
146 | bool was_async) | |
147 | { | |
148 | struct v9fs_inode *v9inode = priv; | |
149 | __le32 version; | |
150 | ||
151 | if (IS_ERR_VALUE(transferred_or_error) && | |
152 | transferred_or_error != -ENOBUFS) { | |
153 | version = cpu_to_le32(v9inode->qid.version); | |
154 | fscache_invalidate(v9fs_inode_cookie(v9inode), &version, | |
874c8ca1 | 155 | i_size_read(&v9inode->netfs.inode), 0); |
93c84614 DH |
156 | } |
157 | } | |
158 | ||
78525c74 | 159 | static int v9fs_vfs_write_folio_locked(struct folio *folio) |
7263cebe | 160 | { |
78525c74 | 161 | struct inode *inode = folio_inode(folio); |
371098c6 | 162 | struct v9fs_inode *v9inode = V9FS_I(inode); |
93c84614 | 163 | struct fscache_cookie *cookie = v9fs_inode_cookie(v9inode); |
78525c74 DH |
164 | loff_t start = folio_pos(folio); |
165 | loff_t i_size = i_size_read(inode); | |
371098c6 | 166 | struct iov_iter from; |
78525c74 DH |
167 | size_t len = folio_size(folio); |
168 | int err; | |
169 | ||
170 | if (start >= i_size) | |
171 | return 0; /* Simultaneous truncation occurred */ | |
7263cebe | 172 | |
78525c74 | 173 | len = min_t(loff_t, i_size - start, len); |
7263cebe | 174 | |
78525c74 | 175 | iov_iter_xarray(&from, WRITE, &folio_mapping(folio)->i_pages, start, len); |
7263cebe | 176 | |
6b39f6d2 AK |
177 | /* We should have writeback_fid always set */ |
178 | BUG_ON(!v9inode->writeback_fid); | |
7263cebe | 179 | |
93c84614 | 180 | folio_wait_fscache(folio); |
78525c74 | 181 | folio_start_writeback(folio); |
371098c6 | 182 | |
eb497943 | 183 | p9_client_write(v9inode->writeback_fid, start, &from, &err); |
7263cebe | 184 | |
93c84614 DH |
185 | if (err == 0 && |
186 | fscache_cookie_enabled(cookie) && | |
187 | test_bit(FSCACHE_COOKIE_IS_CACHING, &cookie->flags)) { | |
188 | folio_start_fscache(folio); | |
189 | fscache_write_to_cache(v9fs_inode_cookie(v9inode), | |
190 | folio_mapping(folio), start, len, i_size, | |
191 | v9fs_write_to_cache_done, v9inode, | |
192 | true); | |
193 | } | |
194 | ||
78525c74 | 195 | folio_end_writeback(folio); |
371098c6 | 196 | return err; |
7263cebe AK |
197 | } |
198 | ||
199 | static int v9fs_vfs_writepage(struct page *page, struct writeback_control *wbc) | |
200 | { | |
78525c74 | 201 | struct folio *folio = page_folio(page); |
7263cebe AK |
202 | int retval; |
203 | ||
78525c74 | 204 | p9_debug(P9_DEBUG_VFS, "folio %p\n", folio); |
fb89b45c | 205 | |
78525c74 | 206 | retval = v9fs_vfs_write_folio_locked(folio); |
7263cebe AK |
207 | if (retval < 0) { |
208 | if (retval == -EAGAIN) { | |
78525c74 | 209 | folio_redirty_for_writepage(wbc, folio); |
7263cebe AK |
210 | retval = 0; |
211 | } else { | |
78525c74 | 212 | mapping_set_error(folio_mapping(folio), retval); |
7263cebe AK |
213 | } |
214 | } else | |
215 | retval = 0; | |
216 | ||
78525c74 | 217 | folio_unlock(folio); |
7263cebe AK |
218 | return retval; |
219 | } | |
220 | ||
76dba927 | 221 | static int v9fs_launder_folio(struct folio *folio) |
60e78d2c | 222 | { |
7263cebe | 223 | int retval; |
7263cebe | 224 | |
78525c74 DH |
225 | if (folio_clear_dirty_for_io(folio)) { |
226 | retval = v9fs_vfs_write_folio_locked(folio); | |
7263cebe AK |
227 | if (retval) |
228 | return retval; | |
229 | } | |
78525c74 | 230 | folio_wait_fscache(folio); |
60e78d2c AK |
231 | return 0; |
232 | } | |
233 | ||
3e24ad2f | 234 | /** |
235 | * v9fs_direct_IO - 9P address space operation for direct I/O | |
3e24ad2f | 236 | * @iocb: target I/O control block |
bc868036 | 237 | * @iter: The data/buffer to use |
3e24ad2f | 238 | * |
239 | * The presence of v9fs_direct_IO() in the address space ops vector | |
240 | * allowes open() O_DIRECT flags which would have failed otherwise. | |
241 | * | |
242 | * In the non-cached mode, we shunt off direct read and write requests before | |
243 | * the VFS gets them, so this method should never be called. | |
244 | * | |
245 | * Direct IO is not 'yet' supported in the cached mode. Hence when | |
246 | * this routine is called through generic_file_aio_read(), the read/write fails | |
247 | * with an error. | |
248 | * | |
249 | */ | |
e959b549 | 250 | static ssize_t |
c8b8e32d | 251 | v9fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter) |
3e24ad2f | 252 | { |
9565a544 | 253 | struct file *file = iocb->ki_filp; |
c8b8e32d | 254 | loff_t pos = iocb->ki_pos; |
42b1ab97 AV |
255 | ssize_t n; |
256 | int err = 0; | |
6e195b0f | 257 | |
6f673763 | 258 | if (iov_iter_rw(iter) == WRITE) { |
42b1ab97 AV |
259 | n = p9_client_write(file->private_data, pos, iter, &err); |
260 | if (n) { | |
9565a544 AV |
261 | struct inode *inode = file_inode(file); |
262 | loff_t i_size = i_size_read(inode); | |
6e195b0f | 263 | |
42b1ab97 AV |
264 | if (pos + n > i_size) |
265 | inode_add_bytes(inode, pos + n - i_size); | |
9565a544 | 266 | } |
42b1ab97 AV |
267 | } else { |
268 | n = p9_client_read(file->private_data, pos, iter, &err); | |
9565a544 | 269 | } |
42b1ab97 | 270 | return n ? n : err; |
3e24ad2f | 271 | } |
7263cebe AK |
272 | |
273 | static int v9fs_write_begin(struct file *filp, struct address_space *mapping, | |
9d6b0cd7 | 274 | loff_t pos, unsigned int len, |
78525c74 | 275 | struct page **subpagep, void **fsdata) |
7263cebe | 276 | { |
eb497943 | 277 | int retval; |
78525c74 | 278 | struct folio *folio; |
eb497943 | 279 | struct v9fs_inode *v9inode = V9FS_I(mapping->host); |
fb89b45c DM |
280 | |
281 | p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping); | |
282 | ||
6b39f6d2 | 283 | BUG_ON(!v9inode->writeback_fid); |
7263cebe | 284 | |
eb497943 DH |
285 | /* Prefetch area to be written into the cache if we're caching this |
286 | * file. We need to do this before we get a lock on the page in case | |
287 | * there's more than one writer competing for the same cache block. | |
288 | */ | |
e81fb419 | 289 | retval = netfs_write_begin(&v9inode->netfs, filp, mapping, pos, len, &folio, fsdata); |
eb497943 DH |
290 | if (retval < 0) |
291 | return retval; | |
7263cebe | 292 | |
78525c74 | 293 | *subpagep = &folio->page; |
7263cebe AK |
294 | return retval; |
295 | } | |
296 | ||
297 | static int v9fs_write_end(struct file *filp, struct address_space *mapping, | |
6e195b0f | 298 | loff_t pos, unsigned int len, unsigned int copied, |
78525c74 | 299 | struct page *subpage, void *fsdata) |
7263cebe AK |
300 | { |
301 | loff_t last_pos = pos + copied; | |
78525c74 DH |
302 | struct folio *folio = page_folio(subpage); |
303 | struct inode *inode = mapping->host; | |
93c84614 | 304 | struct v9fs_inode *v9inode = V9FS_I(inode); |
7263cebe | 305 | |
fb89b45c DM |
306 | p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping); |
307 | ||
78525c74 | 308 | if (!folio_test_uptodate(folio)) { |
56ae414e AL |
309 | if (unlikely(copied < len)) { |
310 | copied = 0; | |
311 | goto out; | |
56ae414e | 312 | } |
eb497943 | 313 | |
78525c74 | 314 | folio_mark_uptodate(folio); |
7263cebe | 315 | } |
eb497943 | 316 | |
7263cebe AK |
317 | /* |
318 | * No need to use i_size_read() here, the i_size | |
319 | * cannot change under us because we hold the i_mutex. | |
320 | */ | |
321 | if (last_pos > inode->i_size) { | |
322 | inode_add_bytes(inode, last_pos - inode->i_size); | |
323 | i_size_write(inode, last_pos); | |
93c84614 | 324 | fscache_update_cookie(v9fs_inode_cookie(v9inode), NULL, &last_pos); |
7263cebe | 325 | } |
78525c74 | 326 | folio_mark_dirty(folio); |
77469c3f | 327 | out: |
78525c74 DH |
328 | folio_unlock(folio); |
329 | folio_put(folio); | |
7263cebe AK |
330 | |
331 | return copied; | |
332 | } | |
333 | ||
93c84614 DH |
334 | #ifdef CONFIG_9P_FSCACHE |
335 | /* | |
336 | * Mark a page as having been made dirty and thus needing writeback. We also | |
337 | * need to pin the cache object to write back to. | |
338 | */ | |
8fb72b4a | 339 | static bool v9fs_dirty_folio(struct address_space *mapping, struct folio *folio) |
93c84614 | 340 | { |
8fb72b4a | 341 | struct v9fs_inode *v9inode = V9FS_I(mapping->host); |
93c84614 | 342 | |
8fb72b4a | 343 | return fscache_dirty_folio(mapping, folio, v9fs_inode_cookie(v9inode)); |
93c84614 DH |
344 | } |
345 | #else | |
8fb72b4a | 346 | #define v9fs_dirty_folio filemap_dirty_folio |
93c84614 | 347 | #endif |
7263cebe | 348 | |
f5e54d6e | 349 | const struct address_space_operations v9fs_addr_operations = { |
6c62371b | 350 | .read_folio = netfs_read_folio, |
bc899ee1 | 351 | .readahead = netfs_readahead, |
8fb72b4a | 352 | .dirty_folio = v9fs_dirty_folio, |
7263cebe AK |
353 | .writepage = v9fs_vfs_writepage, |
354 | .write_begin = v9fs_write_begin, | |
355 | .write_end = v9fs_write_end, | |
a26d3411 | 356 | .release_folio = v9fs_release_folio, |
040cdd4b | 357 | .invalidate_folio = v9fs_invalidate_folio, |
76dba927 | 358 | .launder_folio = v9fs_launder_folio, |
7263cebe | 359 | .direct_IO = v9fs_direct_IO, |
147b31cf | 360 | }; |