Commit | Line | Data |
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147b31cf EVH |
1 | /* |
2 | * linux/fs/9p/vfs_addr.c | |
3 | * | |
4 | * This file contians vfs address (mmap) ops for 9P2000. | |
5 | * | |
6 | * Copyright (C) 2005 by Eric Van Hensbergen <ericvh@gmail.com> | |
7 | * Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov> | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or modify | |
42e8c509 EVH |
10 | * it under the terms of the GNU General Public License version 2 |
11 | * as published by the Free Software Foundation. | |
147b31cf EVH |
12 | * |
13 | * This program is distributed in the hope that it will be useful, | |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | * GNU General Public License for more details. | |
17 | * | |
18 | * You should have received a copy of the GNU General Public License | |
19 | * along with this program; if not, write to: | |
20 | * Free Software Foundation | |
21 | * 51 Franklin Street, Fifth Floor | |
22 | * Boston, MA 02111-1301 USA | |
23 | * | |
24 | */ | |
25 | ||
26 | #include <linux/module.h> | |
27 | #include <linux/errno.h> | |
28 | #include <linux/fs.h> | |
29 | #include <linux/file.h> | |
30 | #include <linux/stat.h> | |
31 | #include <linux/string.h> | |
147b31cf | 32 | #include <linux/inet.h> |
147b31cf EVH |
33 | #include <linux/pagemap.h> |
34 | #include <linux/idr.h> | |
e8edc6e0 | 35 | #include <linux/sched.h> |
e2e40f2c | 36 | #include <linux/uio.h> |
bd238fb4 LI |
37 | #include <net/9p/9p.h> |
38 | #include <net/9p/client.h> | |
147b31cf | 39 | |
147b31cf | 40 | #include "v9fs.h" |
147b31cf | 41 | #include "v9fs_vfs.h" |
60e78d2c | 42 | #include "cache.h" |
7263cebe | 43 | #include "fid.h" |
147b31cf EVH |
44 | |
45 | /** | |
7263cebe | 46 | * v9fs_fid_readpage - read an entire page in from 9P |
147b31cf | 47 | * |
7263cebe | 48 | * @fid: fid being read |
147b31cf EVH |
49 | * @page: structure to page |
50 | * | |
51 | */ | |
7263cebe | 52 | static int v9fs_fid_readpage(struct p9_fid *fid, struct page *page) |
147b31cf | 53 | { |
e1200fe6 AV |
54 | struct inode *inode = page->mapping->host; |
55 | struct bio_vec bvec = {.bv_page = page, .bv_len = PAGE_SIZE}; | |
56 | struct iov_iter to; | |
57 | int retval, err; | |
e03abc0c | 58 | |
5d385153 | 59 | p9_debug(P9_DEBUG_VFS, "\n"); |
60e78d2c AK |
60 | |
61 | BUG_ON(!PageLocked(page)); | |
62 | ||
63 | retval = v9fs_readpage_from_fscache(inode, page); | |
64 | if (retval == 0) | |
65 | return retval; | |
66 | ||
e1200fe6 | 67 | iov_iter_bvec(&to, ITER_BVEC | READ, &bvec, 1, PAGE_SIZE); |
147b31cf | 68 | |
e1200fe6 AV |
69 | retval = p9_client_read(fid, page_offset(page), &to, &err); |
70 | if (err) { | |
60e78d2c | 71 | v9fs_uncache_page(inode, page); |
e1200fe6 | 72 | retval = err; |
bd238fb4 | 73 | goto done; |
60e78d2c | 74 | } |
147b31cf | 75 | |
e1200fe6 | 76 | zero_user(page, retval, PAGE_SIZE - retval); |
147b31cf EVH |
77 | flush_dcache_page(page); |
78 | SetPageUptodate(page); | |
60e78d2c AK |
79 | |
80 | v9fs_readpage_to_fscache(inode, page); | |
147b31cf EVH |
81 | retval = 0; |
82 | ||
bd238fb4 | 83 | done: |
147b31cf EVH |
84 | unlock_page(page); |
85 | return retval; | |
86 | } | |
87 | ||
7263cebe AK |
88 | /** |
89 | * v9fs_vfs_readpage - read an entire page in from 9P | |
90 | * | |
91 | * @filp: file being read | |
92 | * @page: structure to page | |
93 | * | |
94 | */ | |
95 | ||
96 | static int v9fs_vfs_readpage(struct file *filp, struct page *page) | |
97 | { | |
98 | return v9fs_fid_readpage(filp->private_data, page); | |
99 | } | |
100 | ||
60e78d2c AK |
101 | /** |
102 | * v9fs_vfs_readpages - read a set of pages from 9P | |
103 | * | |
104 | * @filp: file being read | |
105 | * @mapping: the address space | |
106 | * @pages: list of pages to read | |
107 | * @nr_pages: count of pages to read | |
108 | * | |
109 | */ | |
110 | ||
111 | static int v9fs_vfs_readpages(struct file *filp, struct address_space *mapping, | |
112 | struct list_head *pages, unsigned nr_pages) | |
113 | { | |
114 | int ret = 0; | |
115 | struct inode *inode; | |
116 | ||
117 | inode = mapping->host; | |
5d385153 | 118 | p9_debug(P9_DEBUG_VFS, "inode: %p file: %p\n", inode, filp); |
60e78d2c AK |
119 | |
120 | ret = v9fs_readpages_from_fscache(inode, mapping, pages, &nr_pages); | |
121 | if (ret == 0) | |
122 | return ret; | |
123 | ||
124 | ret = read_cache_pages(mapping, pages, (void *)v9fs_vfs_readpage, filp); | |
5d385153 | 125 | p9_debug(P9_DEBUG_VFS, " = %d\n", ret); |
60e78d2c AK |
126 | return ret; |
127 | } | |
128 | ||
129 | /** | |
130 | * v9fs_release_page - release the private state associated with a page | |
131 | * | |
132 | * Returns 1 if the page can be released, false otherwise. | |
133 | */ | |
134 | ||
135 | static int v9fs_release_page(struct page *page, gfp_t gfp) | |
136 | { | |
137 | if (PagePrivate(page)) | |
138 | return 0; | |
60e78d2c AK |
139 | return v9fs_fscache_release_page(page, gfp); |
140 | } | |
141 | ||
142 | /** | |
143 | * v9fs_invalidate_page - Invalidate a page completely or partially | |
144 | * | |
145 | * @page: structure to page | |
146 | * @offset: offset in the page | |
147 | */ | |
148 | ||
d47992f8 LC |
149 | static void v9fs_invalidate_page(struct page *page, unsigned int offset, |
150 | unsigned int length) | |
60e78d2c | 151 | { |
7263cebe AK |
152 | /* |
153 | * If called with zero offset, we should release | |
154 | * the private state assocated with the page | |
155 | */ | |
d47992f8 | 156 | if (offset == 0 && length == PAGE_CACHE_SIZE) |
60e78d2c AK |
157 | v9fs_fscache_invalidate_page(page); |
158 | } | |
159 | ||
7263cebe AK |
160 | static int v9fs_vfs_writepage_locked(struct page *page) |
161 | { | |
7263cebe | 162 | struct inode *inode = page->mapping->host; |
371098c6 AV |
163 | struct v9fs_inode *v9inode = V9FS_I(inode); |
164 | loff_t size = i_size_read(inode); | |
165 | struct iov_iter from; | |
166 | struct bio_vec bvec; | |
167 | int err, len; | |
7263cebe | 168 | |
7263cebe AK |
169 | if (page->index == size >> PAGE_CACHE_SHIFT) |
170 | len = size & ~PAGE_CACHE_MASK; | |
171 | else | |
172 | len = PAGE_CACHE_SIZE; | |
173 | ||
371098c6 AV |
174 | bvec.bv_page = page; |
175 | bvec.bv_offset = 0; | |
176 | bvec.bv_len = len; | |
177 | iov_iter_bvec(&from, ITER_BVEC | WRITE, &bvec, 1, len); | |
7263cebe | 178 | |
6b39f6d2 AK |
179 | /* We should have writeback_fid always set */ |
180 | BUG_ON(!v9inode->writeback_fid); | |
7263cebe | 181 | |
371098c6 AV |
182 | set_page_writeback(page); |
183 | ||
184 | p9_client_write(v9inode->writeback_fid, page_offset(page), &from, &err); | |
7263cebe | 185 | |
7263cebe | 186 | end_page_writeback(page); |
371098c6 | 187 | return err; |
7263cebe AK |
188 | } |
189 | ||
190 | static int v9fs_vfs_writepage(struct page *page, struct writeback_control *wbc) | |
191 | { | |
192 | int retval; | |
193 | ||
fb89b45c DM |
194 | p9_debug(P9_DEBUG_VFS, "page %p\n", page); |
195 | ||
7263cebe AK |
196 | retval = v9fs_vfs_writepage_locked(page); |
197 | if (retval < 0) { | |
198 | if (retval == -EAGAIN) { | |
199 | redirty_page_for_writepage(wbc, page); | |
200 | retval = 0; | |
201 | } else { | |
202 | SetPageError(page); | |
203 | mapping_set_error(page->mapping, retval); | |
204 | } | |
205 | } else | |
206 | retval = 0; | |
207 | ||
208 | unlock_page(page); | |
209 | return retval; | |
210 | } | |
211 | ||
60e78d2c AK |
212 | /** |
213 | * v9fs_launder_page - Writeback a dirty page | |
60e78d2c AK |
214 | * Returns 0 on success. |
215 | */ | |
216 | ||
217 | static int v9fs_launder_page(struct page *page) | |
218 | { | |
7263cebe | 219 | int retval; |
2efda799 | 220 | struct inode *inode = page->mapping->host; |
7263cebe | 221 | |
2efda799 | 222 | v9fs_fscache_wait_on_page_write(inode, page); |
7263cebe AK |
223 | if (clear_page_dirty_for_io(page)) { |
224 | retval = v9fs_vfs_writepage_locked(page); | |
225 | if (retval) | |
226 | return retval; | |
227 | } | |
60e78d2c AK |
228 | return 0; |
229 | } | |
230 | ||
3e24ad2f | 231 | /** |
232 | * v9fs_direct_IO - 9P address space operation for direct I/O | |
3e24ad2f | 233 | * @iocb: target I/O control block |
3e24ad2f | 234 | * @pos: offset in file to begin the operation |
3e24ad2f | 235 | * |
236 | * The presence of v9fs_direct_IO() in the address space ops vector | |
237 | * allowes open() O_DIRECT flags which would have failed otherwise. | |
238 | * | |
239 | * In the non-cached mode, we shunt off direct read and write requests before | |
240 | * the VFS gets them, so this method should never be called. | |
241 | * | |
242 | * Direct IO is not 'yet' supported in the cached mode. Hence when | |
243 | * this routine is called through generic_file_aio_read(), the read/write fails | |
244 | * with an error. | |
245 | * | |
246 | */ | |
e959b549 | 247 | static ssize_t |
22c6186e | 248 | v9fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t pos) |
3e24ad2f | 249 | { |
9565a544 | 250 | struct file *file = iocb->ki_filp; |
42b1ab97 AV |
251 | ssize_t n; |
252 | int err = 0; | |
6f673763 | 253 | if (iov_iter_rw(iter) == WRITE) { |
42b1ab97 AV |
254 | n = p9_client_write(file->private_data, pos, iter, &err); |
255 | if (n) { | |
9565a544 AV |
256 | struct inode *inode = file_inode(file); |
257 | loff_t i_size = i_size_read(inode); | |
42b1ab97 AV |
258 | if (pos + n > i_size) |
259 | inode_add_bytes(inode, pos + n - i_size); | |
9565a544 | 260 | } |
42b1ab97 AV |
261 | } else { |
262 | n = p9_client_read(file->private_data, pos, iter, &err); | |
9565a544 | 263 | } |
42b1ab97 | 264 | return n ? n : err; |
3e24ad2f | 265 | } |
7263cebe AK |
266 | |
267 | static int v9fs_write_begin(struct file *filp, struct address_space *mapping, | |
268 | loff_t pos, unsigned len, unsigned flags, | |
269 | struct page **pagep, void **fsdata) | |
270 | { | |
271 | int retval = 0; | |
272 | struct page *page; | |
6b39f6d2 | 273 | struct v9fs_inode *v9inode; |
7263cebe AK |
274 | pgoff_t index = pos >> PAGE_CACHE_SHIFT; |
275 | struct inode *inode = mapping->host; | |
276 | ||
fb89b45c DM |
277 | |
278 | p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping); | |
279 | ||
6b39f6d2 | 280 | v9inode = V9FS_I(inode); |
7263cebe AK |
281 | start: |
282 | page = grab_cache_page_write_begin(mapping, index, flags); | |
283 | if (!page) { | |
284 | retval = -ENOMEM; | |
285 | goto out; | |
286 | } | |
6b39f6d2 | 287 | BUG_ON(!v9inode->writeback_fid); |
7263cebe AK |
288 | if (PageUptodate(page)) |
289 | goto out; | |
290 | ||
291 | if (len == PAGE_CACHE_SIZE) | |
292 | goto out; | |
293 | ||
6b39f6d2 | 294 | retval = v9fs_fid_readpage(v9inode->writeback_fid, page); |
7263cebe AK |
295 | page_cache_release(page); |
296 | if (!retval) | |
297 | goto start; | |
298 | out: | |
299 | *pagep = page; | |
300 | return retval; | |
301 | } | |
302 | ||
303 | static int v9fs_write_end(struct file *filp, struct address_space *mapping, | |
304 | loff_t pos, unsigned len, unsigned copied, | |
305 | struct page *page, void *fsdata) | |
306 | { | |
307 | loff_t last_pos = pos + copied; | |
308 | struct inode *inode = page->mapping->host; | |
309 | ||
fb89b45c DM |
310 | p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping); |
311 | ||
7263cebe AK |
312 | if (unlikely(copied < len)) { |
313 | /* | |
314 | * zero out the rest of the area | |
315 | */ | |
316 | unsigned from = pos & (PAGE_CACHE_SIZE - 1); | |
317 | ||
318 | zero_user(page, from + copied, len - copied); | |
319 | flush_dcache_page(page); | |
320 | } | |
321 | ||
322 | if (!PageUptodate(page)) | |
323 | SetPageUptodate(page); | |
324 | /* | |
325 | * No need to use i_size_read() here, the i_size | |
326 | * cannot change under us because we hold the i_mutex. | |
327 | */ | |
328 | if (last_pos > inode->i_size) { | |
329 | inode_add_bytes(inode, last_pos - inode->i_size); | |
330 | i_size_write(inode, last_pos); | |
331 | } | |
332 | set_page_dirty(page); | |
333 | unlock_page(page); | |
334 | page_cache_release(page); | |
335 | ||
336 | return copied; | |
337 | } | |
338 | ||
339 | ||
f5e54d6e | 340 | const struct address_space_operations v9fs_addr_operations = { |
7263cebe AK |
341 | .readpage = v9fs_vfs_readpage, |
342 | .readpages = v9fs_vfs_readpages, | |
343 | .set_page_dirty = __set_page_dirty_nobuffers, | |
344 | .writepage = v9fs_vfs_writepage, | |
345 | .write_begin = v9fs_write_begin, | |
346 | .write_end = v9fs_write_end, | |
347 | .releasepage = v9fs_release_page, | |
348 | .invalidatepage = v9fs_invalidate_page, | |
349 | .launder_page = v9fs_launder_page, | |
350 | .direct_IO = v9fs_direct_IO, | |
147b31cf | 351 | }; |