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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 | { | |
79 | struct fscache_cookie *cookie = v9fs_inode_cookie(V9FS_I(inode)); | |
147b31cf | 80 | |
eb497943 DH |
81 | return fscache_cookie_enabled(cookie) && !hlist_empty(&cookie->backing_objects); |
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 | { | |
90 | struct fscache_cookie *cookie = v9fs_inode_cookie(V9FS_I(rreq->inode)); | |
91 | ||
92 | return fscache_begin_read_operation(rreq, cookie); | |
147b31cf EVH |
93 | } |
94 | ||
eb497943 DH |
95 | static const struct netfs_read_request_ops v9fs_req_ops = { |
96 | .init_rreq = v9fs_init_rreq, | |
97 | .is_cache_enabled = v9fs_is_cache_enabled, | |
98 | .begin_cache_operation = v9fs_begin_cache_operation, | |
99 | .issue_op = v9fs_req_issue_op, | |
100 | .cleanup = v9fs_req_cleanup, | |
101 | }; | |
102 | ||
7263cebe AK |
103 | /** |
104 | * v9fs_vfs_readpage - read an entire page in from 9P | |
eb497943 | 105 | * @file: file being read |
7263cebe AK |
106 | * @page: structure to page |
107 | * | |
108 | */ | |
eb497943 | 109 | static int v9fs_vfs_readpage(struct file *file, struct page *page) |
7263cebe | 110 | { |
78525c74 DH |
111 | struct folio *folio = page_folio(page); |
112 | ||
113 | return netfs_readpage(file, folio, &v9fs_req_ops, NULL); | |
7263cebe AK |
114 | } |
115 | ||
60e78d2c | 116 | /** |
eb497943 DH |
117 | * v9fs_vfs_readahead - read a set of pages from 9P |
118 | * @ractl: The readahead parameters | |
60e78d2c | 119 | */ |
eb497943 | 120 | static void v9fs_vfs_readahead(struct readahead_control *ractl) |
60e78d2c | 121 | { |
eb497943 | 122 | netfs_readahead(ractl, &v9fs_req_ops, NULL); |
60e78d2c AK |
123 | } |
124 | ||
125 | /** | |
126 | * v9fs_release_page - release the private state associated with a page | |
bc868036 DH |
127 | * @page: The page to be released |
128 | * @gfp: The caller's allocation restrictions | |
60e78d2c AK |
129 | * |
130 | * Returns 1 if the page can be released, false otherwise. | |
131 | */ | |
132 | ||
133 | static int v9fs_release_page(struct page *page, gfp_t gfp) | |
134 | { | |
78525c74 DH |
135 | struct folio *folio = page_folio(page); |
136 | ||
137 | if (folio_test_private(folio)) | |
60e78d2c | 138 | return 0; |
eb497943 | 139 | #ifdef CONFIG_9P_FSCACHE |
78525c74 | 140 | if (folio_test_fscache(folio)) { |
eb497943 DH |
141 | if (!(gfp & __GFP_DIRECT_RECLAIM) || !(gfp & __GFP_FS)) |
142 | return 0; | |
78525c74 | 143 | folio_wait_fscache(folio); |
eb497943 DH |
144 | } |
145 | #endif | |
146 | return 1; | |
60e78d2c AK |
147 | } |
148 | ||
149 | /** | |
150 | * v9fs_invalidate_page - Invalidate a page completely or partially | |
bc868036 DH |
151 | * @page: The page to be invalidated |
152 | * @offset: offset of the invalidated region | |
153 | * @length: length of the invalidated region | |
60e78d2c AK |
154 | */ |
155 | ||
d47992f8 LC |
156 | static void v9fs_invalidate_page(struct page *page, unsigned int offset, |
157 | unsigned int length) | |
60e78d2c | 158 | { |
78525c74 DH |
159 | struct folio *folio = page_folio(page); |
160 | ||
161 | folio_wait_fscache(folio); | |
60e78d2c AK |
162 | } |
163 | ||
78525c74 | 164 | static int v9fs_vfs_write_folio_locked(struct folio *folio) |
7263cebe | 165 | { |
78525c74 | 166 | struct inode *inode = folio_inode(folio); |
371098c6 | 167 | struct v9fs_inode *v9inode = V9FS_I(inode); |
78525c74 DH |
168 | loff_t start = folio_pos(folio); |
169 | loff_t i_size = i_size_read(inode); | |
371098c6 | 170 | struct iov_iter from; |
78525c74 DH |
171 | size_t len = folio_size(folio); |
172 | int err; | |
173 | ||
174 | if (start >= i_size) | |
175 | return 0; /* Simultaneous truncation occurred */ | |
7263cebe | 176 | |
78525c74 | 177 | len = min_t(loff_t, i_size - start, len); |
7263cebe | 178 | |
78525c74 | 179 | iov_iter_xarray(&from, WRITE, &folio_mapping(folio)->i_pages, start, len); |
7263cebe | 180 | |
6b39f6d2 AK |
181 | /* We should have writeback_fid always set */ |
182 | BUG_ON(!v9inode->writeback_fid); | |
7263cebe | 183 | |
78525c74 | 184 | folio_start_writeback(folio); |
371098c6 | 185 | |
eb497943 | 186 | p9_client_write(v9inode->writeback_fid, start, &from, &err); |
7263cebe | 187 | |
78525c74 | 188 | folio_end_writeback(folio); |
371098c6 | 189 | return err; |
7263cebe AK |
190 | } |
191 | ||
192 | static int v9fs_vfs_writepage(struct page *page, struct writeback_control *wbc) | |
193 | { | |
78525c74 | 194 | struct folio *folio = page_folio(page); |
7263cebe AK |
195 | int retval; |
196 | ||
78525c74 | 197 | p9_debug(P9_DEBUG_VFS, "folio %p\n", folio); |
fb89b45c | 198 | |
78525c74 | 199 | retval = v9fs_vfs_write_folio_locked(folio); |
7263cebe AK |
200 | if (retval < 0) { |
201 | if (retval == -EAGAIN) { | |
78525c74 | 202 | folio_redirty_for_writepage(wbc, folio); |
7263cebe AK |
203 | retval = 0; |
204 | } else { | |
78525c74 | 205 | mapping_set_error(folio_mapping(folio), retval); |
7263cebe AK |
206 | } |
207 | } else | |
208 | retval = 0; | |
209 | ||
78525c74 | 210 | folio_unlock(folio); |
7263cebe AK |
211 | return retval; |
212 | } | |
213 | ||
60e78d2c AK |
214 | /** |
215 | * v9fs_launder_page - Writeback a dirty page | |
bc868036 DH |
216 | * @page: The page to be cleaned up |
217 | * | |
60e78d2c AK |
218 | * Returns 0 on success. |
219 | */ | |
220 | ||
221 | static int v9fs_launder_page(struct page *page) | |
222 | { | |
78525c74 | 223 | struct folio *folio = page_folio(page); |
7263cebe | 224 | int retval; |
7263cebe | 225 | |
78525c74 DH |
226 | if (folio_clear_dirty_for_io(folio)) { |
227 | retval = v9fs_vfs_write_folio_locked(folio); | |
7263cebe AK |
228 | if (retval) |
229 | return retval; | |
230 | } | |
78525c74 | 231 | folio_wait_fscache(folio); |
60e78d2c AK |
232 | return 0; |
233 | } | |
234 | ||
3e24ad2f | 235 | /** |
236 | * v9fs_direct_IO - 9P address space operation for direct I/O | |
3e24ad2f | 237 | * @iocb: target I/O control block |
bc868036 | 238 | * @iter: The data/buffer to use |
3e24ad2f | 239 | * |
240 | * The presence of v9fs_direct_IO() in the address space ops vector | |
241 | * allowes open() O_DIRECT flags which would have failed otherwise. | |
242 | * | |
243 | * In the non-cached mode, we shunt off direct read and write requests before | |
244 | * the VFS gets them, so this method should never be called. | |
245 | * | |
246 | * Direct IO is not 'yet' supported in the cached mode. Hence when | |
247 | * this routine is called through generic_file_aio_read(), the read/write fails | |
248 | * with an error. | |
249 | * | |
250 | */ | |
e959b549 | 251 | static ssize_t |
c8b8e32d | 252 | v9fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter) |
3e24ad2f | 253 | { |
9565a544 | 254 | struct file *file = iocb->ki_filp; |
c8b8e32d | 255 | loff_t pos = iocb->ki_pos; |
42b1ab97 AV |
256 | ssize_t n; |
257 | int err = 0; | |
6e195b0f | 258 | |
6f673763 | 259 | if (iov_iter_rw(iter) == WRITE) { |
42b1ab97 AV |
260 | n = p9_client_write(file->private_data, pos, iter, &err); |
261 | if (n) { | |
9565a544 AV |
262 | struct inode *inode = file_inode(file); |
263 | loff_t i_size = i_size_read(inode); | |
6e195b0f | 264 | |
42b1ab97 AV |
265 | if (pos + n > i_size) |
266 | inode_add_bytes(inode, pos + n - i_size); | |
9565a544 | 267 | } |
42b1ab97 AV |
268 | } else { |
269 | n = p9_client_read(file->private_data, pos, iter, &err); | |
9565a544 | 270 | } |
42b1ab97 | 271 | return n ? n : err; |
3e24ad2f | 272 | } |
7263cebe AK |
273 | |
274 | static int v9fs_write_begin(struct file *filp, struct address_space *mapping, | |
6e195b0f | 275 | loff_t pos, unsigned int len, unsigned int flags, |
78525c74 | 276 | struct page **subpagep, void **fsdata) |
7263cebe | 277 | { |
eb497943 | 278 | int retval; |
78525c74 | 279 | struct folio *folio; |
eb497943 | 280 | struct v9fs_inode *v9inode = V9FS_I(mapping->host); |
fb89b45c DM |
281 | |
282 | p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping); | |
283 | ||
6b39f6d2 | 284 | BUG_ON(!v9inode->writeback_fid); |
7263cebe | 285 | |
eb497943 DH |
286 | /* Prefetch area to be written into the cache if we're caching this |
287 | * file. We need to do this before we get a lock on the page in case | |
288 | * there's more than one writer competing for the same cache block. | |
289 | */ | |
78525c74 | 290 | retval = netfs_write_begin(filp, mapping, pos, len, flags, &folio, fsdata, |
eb497943 DH |
291 | &v9fs_req_ops, NULL); |
292 | if (retval < 0) | |
293 | return retval; | |
7263cebe | 294 | |
78525c74 | 295 | *subpagep = &folio->page; |
7263cebe AK |
296 | return retval; |
297 | } | |
298 | ||
299 | static int v9fs_write_end(struct file *filp, struct address_space *mapping, | |
6e195b0f | 300 | loff_t pos, unsigned int len, unsigned int copied, |
78525c74 | 301 | struct page *subpage, void *fsdata) |
7263cebe AK |
302 | { |
303 | loff_t last_pos = pos + copied; | |
78525c74 DH |
304 | struct folio *folio = page_folio(subpage); |
305 | struct inode *inode = mapping->host; | |
7263cebe | 306 | |
fb89b45c DM |
307 | p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping); |
308 | ||
78525c74 | 309 | if (!folio_test_uptodate(folio)) { |
56ae414e AL |
310 | if (unlikely(copied < len)) { |
311 | copied = 0; | |
312 | goto out; | |
56ae414e | 313 | } |
eb497943 | 314 | |
78525c74 | 315 | folio_mark_uptodate(folio); |
7263cebe | 316 | } |
eb497943 | 317 | |
7263cebe AK |
318 | /* |
319 | * No need to use i_size_read() here, the i_size | |
320 | * cannot change under us because we hold the i_mutex. | |
321 | */ | |
322 | if (last_pos > inode->i_size) { | |
323 | inode_add_bytes(inode, last_pos - inode->i_size); | |
324 | i_size_write(inode, last_pos); | |
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 | ||
334 | ||
f5e54d6e | 335 | const struct address_space_operations v9fs_addr_operations = { |
7263cebe | 336 | .readpage = v9fs_vfs_readpage, |
eb497943 | 337 | .readahead = v9fs_vfs_readahead, |
7263cebe AK |
338 | .set_page_dirty = __set_page_dirty_nobuffers, |
339 | .writepage = v9fs_vfs_writepage, | |
340 | .write_begin = v9fs_write_begin, | |
341 | .write_end = v9fs_write_end, | |
342 | .releasepage = v9fs_release_page, | |
343 | .invalidatepage = v9fs_invalidate_page, | |
344 | .launder_page = v9fs_launder_page, | |
345 | .direct_IO = v9fs_direct_IO, | |
147b31cf | 346 | }; |