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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
10 * it under the terms of the GNU General Public License version 2
11 * as published by the Free Software Foundation.
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>
32#include <linux/inet.h>
33#include <linux/pagemap.h>
34#include <linux/idr.h>
35#include <linux/sched.h>
36#include <linux/uio.h>
37#include <net/9p/9p.h>
38#include <net/9p/client.h>
39
40#include "v9fs.h"
41#include "v9fs_vfs.h"
42#include "cache.h"
43#include "fid.h"
44
45/**
46 * v9fs_fid_readpage - read an entire page in from 9P
47 *
48 * @fid: fid being read
49 * @page: structure to page
50 *
51 */
52static int v9fs_fid_readpage(struct p9_fid *fid, struct page *page)
53{
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;
58
59 p9_debug(P9_DEBUG_VFS, "\n");
60
61 BUG_ON(!PageLocked(page));
62
63 retval = v9fs_readpage_from_fscache(inode, page);
64 if (retval == 0)
65 return retval;
66
67 iov_iter_bvec(&to, ITER_BVEC | READ, &bvec, 1, PAGE_SIZE);
68
69 retval = p9_client_read(fid, page_offset(page), &to, &err);
70 if (err) {
71 v9fs_uncache_page(inode, page);
72 retval = err;
73 goto done;
74 }
75
76 zero_user(page, retval, PAGE_SIZE - retval);
77 flush_dcache_page(page);
78 SetPageUptodate(page);
79
80 v9fs_readpage_to_fscache(inode, page);
81 retval = 0;
82
83done:
84 unlock_page(page);
85 return retval;
86}
87
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
96static int v9fs_vfs_readpage(struct file *filp, struct page *page)
97{
98 return v9fs_fid_readpage(filp->private_data, page);
99}
100
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
111static 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;
118 p9_debug(P9_DEBUG_VFS, "inode: %p file: %p\n", inode, filp);
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);
125 p9_debug(P9_DEBUG_VFS, " = %d\n", ret);
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
135static int v9fs_release_page(struct page *page, gfp_t gfp)
136{
137 if (PagePrivate(page))
138 return 0;
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
149static void v9fs_invalidate_page(struct page *page, unsigned int offset,
150 unsigned int length)
151{
152 /*
153 * If called with zero offset, we should release
154 * the private state assocated with the page
155 */
156 if (offset == 0 && length == PAGE_SIZE)
157 v9fs_fscache_invalidate_page(page);
158}
159
160static int v9fs_vfs_writepage_locked(struct page *page)
161{
162 struct inode *inode = page->mapping->host;
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;
168
169 if (page->index == size >> PAGE_SHIFT)
170 len = size & ~PAGE_MASK;
171 else
172 len = PAGE_SIZE;
173
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);
178
179 /* We should have writeback_fid always set */
180 BUG_ON(!v9inode->writeback_fid);
181
182 set_page_writeback(page);
183
184 p9_client_write(v9inode->writeback_fid, page_offset(page), &from, &err);
185
186 end_page_writeback(page);
187 return err;
188}
189
190static int v9fs_vfs_writepage(struct page *page, struct writeback_control *wbc)
191{
192 int retval;
193
194 p9_debug(P9_DEBUG_VFS, "page %p\n", page);
195
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
212/**
213 * v9fs_launder_page - Writeback a dirty page
214 * Returns 0 on success.
215 */
216
217static int v9fs_launder_page(struct page *page)
218{
219 int retval;
220 struct inode *inode = page->mapping->host;
221
222 v9fs_fscache_wait_on_page_write(inode, page);
223 if (clear_page_dirty_for_io(page)) {
224 retval = v9fs_vfs_writepage_locked(page);
225 if (retval)
226 return retval;
227 }
228 return 0;
229}
230
231/**
232 * v9fs_direct_IO - 9P address space operation for direct I/O
233 * @iocb: target I/O control block
234 * @pos: offset in file to begin the operation
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 */
247static ssize_t
248v9fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t pos)
249{
250 struct file *file = iocb->ki_filp;
251 ssize_t n;
252 int err = 0;
253 if (iov_iter_rw(iter) == WRITE) {
254 n = p9_client_write(file->private_data, pos, iter, &err);
255 if (n) {
256 struct inode *inode = file_inode(file);
257 loff_t i_size = i_size_read(inode);
258 if (pos + n > i_size)
259 inode_add_bytes(inode, pos + n - i_size);
260 }
261 } else {
262 n = p9_client_read(file->private_data, pos, iter, &err);
263 }
264 return n ? n : err;
265}
266
267static 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;
273 struct v9fs_inode *v9inode;
274 pgoff_t index = pos >> PAGE_SHIFT;
275 struct inode *inode = mapping->host;
276
277
278 p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
279
280 v9inode = V9FS_I(inode);
281start:
282 page = grab_cache_page_write_begin(mapping, index, flags);
283 if (!page) {
284 retval = -ENOMEM;
285 goto out;
286 }
287 BUG_ON(!v9inode->writeback_fid);
288 if (PageUptodate(page))
289 goto out;
290
291 if (len == PAGE_SIZE)
292 goto out;
293
294 retval = v9fs_fid_readpage(v9inode->writeback_fid, page);
295 put_page(page);
296 if (!retval)
297 goto start;
298out:
299 *pagep = page;
300 return retval;
301}
302
303static 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
310 p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
311
312 if (unlikely(copied < len)) {
313 /*
314 * zero out the rest of the area
315 */
316 unsigned from = pos & (PAGE_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 put_page(page);
335
336 return copied;
337}
338
339
340const struct address_space_operations v9fs_addr_operations = {
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,
351};
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/fs/9p/vfs_addr.c
4 *
5 * This file contians vfs address (mmap) ops for 9P2000.
6 *
7 * Copyright (C) 2005 by Eric Van Hensbergen <ericvh@gmail.com>
8 * Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
9 */
10
11#include <linux/module.h>
12#include <linux/errno.h>
13#include <linux/fs.h>
14#include <linux/file.h>
15#include <linux/stat.h>
16#include <linux/string.h>
17#include <linux/inet.h>
18#include <linux/pagemap.h>
19#include <linux/idr.h>
20#include <linux/sched.h>
21#include <linux/uio.h>
22#include <linux/bvec.h>
23#include <net/9p/9p.h>
24#include <net/9p/client.h>
25
26#include "v9fs.h"
27#include "v9fs_vfs.h"
28#include "cache.h"
29#include "fid.h"
30
31/**
32 * v9fs_fid_readpage - read an entire page in from 9P
33 *
34 * @fid: fid being read
35 * @page: structure to page
36 *
37 */
38static int v9fs_fid_readpage(void *data, struct page *page)
39{
40 struct p9_fid *fid = data;
41 struct inode *inode = page->mapping->host;
42 struct bio_vec bvec = {.bv_page = page, .bv_len = PAGE_SIZE};
43 struct iov_iter to;
44 int retval, err;
45
46 p9_debug(P9_DEBUG_VFS, "\n");
47
48 BUG_ON(!PageLocked(page));
49
50 retval = v9fs_readpage_from_fscache(inode, page);
51 if (retval == 0)
52 return retval;
53
54 iov_iter_bvec(&to, READ, &bvec, 1, PAGE_SIZE);
55
56 retval = p9_client_read(fid, page_offset(page), &to, &err);
57 if (err) {
58 v9fs_uncache_page(inode, page);
59 retval = err;
60 goto done;
61 }
62
63 zero_user(page, retval, PAGE_SIZE - retval);
64 flush_dcache_page(page);
65 SetPageUptodate(page);
66
67 v9fs_readpage_to_fscache(inode, page);
68 retval = 0;
69
70done:
71 unlock_page(page);
72 return retval;
73}
74
75/**
76 * v9fs_vfs_readpage - read an entire page in from 9P
77 *
78 * @filp: file being read
79 * @page: structure to page
80 *
81 */
82
83static int v9fs_vfs_readpage(struct file *filp, struct page *page)
84{
85 return v9fs_fid_readpage(filp->private_data, page);
86}
87
88/**
89 * v9fs_vfs_readpages - read a set of pages from 9P
90 *
91 * @filp: file being read
92 * @mapping: the address space
93 * @pages: list of pages to read
94 * @nr_pages: count of pages to read
95 *
96 */
97
98static int v9fs_vfs_readpages(struct file *filp, struct address_space *mapping,
99 struct list_head *pages, unsigned nr_pages)
100{
101 int ret = 0;
102 struct inode *inode;
103
104 inode = mapping->host;
105 p9_debug(P9_DEBUG_VFS, "inode: %p file: %p\n", inode, filp);
106
107 ret = v9fs_readpages_from_fscache(inode, mapping, pages, &nr_pages);
108 if (ret == 0)
109 return ret;
110
111 ret = read_cache_pages(mapping, pages, v9fs_fid_readpage,
112 filp->private_data);
113 p9_debug(P9_DEBUG_VFS, " = %d\n", ret);
114 return ret;
115}
116
117/**
118 * v9fs_release_page - release the private state associated with a page
119 *
120 * Returns 1 if the page can be released, false otherwise.
121 */
122
123static int v9fs_release_page(struct page *page, gfp_t gfp)
124{
125 if (PagePrivate(page))
126 return 0;
127 return v9fs_fscache_release_page(page, gfp);
128}
129
130/**
131 * v9fs_invalidate_page - Invalidate a page completely or partially
132 *
133 * @page: structure to page
134 * @offset: offset in the page
135 */
136
137static void v9fs_invalidate_page(struct page *page, unsigned int offset,
138 unsigned int length)
139{
140 /*
141 * If called with zero offset, we should release
142 * the private state assocated with the page
143 */
144 if (offset == 0 && length == PAGE_SIZE)
145 v9fs_fscache_invalidate_page(page);
146}
147
148static int v9fs_vfs_writepage_locked(struct page *page)
149{
150 struct inode *inode = page->mapping->host;
151 struct v9fs_inode *v9inode = V9FS_I(inode);
152 loff_t size = i_size_read(inode);
153 struct iov_iter from;
154 struct bio_vec bvec;
155 int err, len;
156
157 if (page->index == size >> PAGE_SHIFT)
158 len = size & ~PAGE_MASK;
159 else
160 len = PAGE_SIZE;
161
162 bvec.bv_page = page;
163 bvec.bv_offset = 0;
164 bvec.bv_len = len;
165 iov_iter_bvec(&from, WRITE, &bvec, 1, len);
166
167 /* We should have writeback_fid always set */
168 BUG_ON(!v9inode->writeback_fid);
169
170 set_page_writeback(page);
171
172 p9_client_write(v9inode->writeback_fid, page_offset(page), &from, &err);
173
174 end_page_writeback(page);
175 return err;
176}
177
178static int v9fs_vfs_writepage(struct page *page, struct writeback_control *wbc)
179{
180 int retval;
181
182 p9_debug(P9_DEBUG_VFS, "page %p\n", page);
183
184 retval = v9fs_vfs_writepage_locked(page);
185 if (retval < 0) {
186 if (retval == -EAGAIN) {
187 redirty_page_for_writepage(wbc, page);
188 retval = 0;
189 } else {
190 SetPageError(page);
191 mapping_set_error(page->mapping, retval);
192 }
193 } else
194 retval = 0;
195
196 unlock_page(page);
197 return retval;
198}
199
200/**
201 * v9fs_launder_page - Writeback a dirty page
202 * Returns 0 on success.
203 */
204
205static int v9fs_launder_page(struct page *page)
206{
207 int retval;
208 struct inode *inode = page->mapping->host;
209
210 v9fs_fscache_wait_on_page_write(inode, page);
211 if (clear_page_dirty_for_io(page)) {
212 retval = v9fs_vfs_writepage_locked(page);
213 if (retval)
214 return retval;
215 }
216 return 0;
217}
218
219/**
220 * v9fs_direct_IO - 9P address space operation for direct I/O
221 * @iocb: target I/O control block
222 *
223 * The presence of v9fs_direct_IO() in the address space ops vector
224 * allowes open() O_DIRECT flags which would have failed otherwise.
225 *
226 * In the non-cached mode, we shunt off direct read and write requests before
227 * the VFS gets them, so this method should never be called.
228 *
229 * Direct IO is not 'yet' supported in the cached mode. Hence when
230 * this routine is called through generic_file_aio_read(), the read/write fails
231 * with an error.
232 *
233 */
234static ssize_t
235v9fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
236{
237 struct file *file = iocb->ki_filp;
238 loff_t pos = iocb->ki_pos;
239 ssize_t n;
240 int err = 0;
241 if (iov_iter_rw(iter) == WRITE) {
242 n = p9_client_write(file->private_data, pos, iter, &err);
243 if (n) {
244 struct inode *inode = file_inode(file);
245 loff_t i_size = i_size_read(inode);
246 if (pos + n > i_size)
247 inode_add_bytes(inode, pos + n - i_size);
248 }
249 } else {
250 n = p9_client_read(file->private_data, pos, iter, &err);
251 }
252 return n ? n : err;
253}
254
255static int v9fs_write_begin(struct file *filp, struct address_space *mapping,
256 loff_t pos, unsigned len, unsigned flags,
257 struct page **pagep, void **fsdata)
258{
259 int retval = 0;
260 struct page *page;
261 struct v9fs_inode *v9inode;
262 pgoff_t index = pos >> PAGE_SHIFT;
263 struct inode *inode = mapping->host;
264
265
266 p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
267
268 v9inode = V9FS_I(inode);
269start:
270 page = grab_cache_page_write_begin(mapping, index, flags);
271 if (!page) {
272 retval = -ENOMEM;
273 goto out;
274 }
275 BUG_ON(!v9inode->writeback_fid);
276 if (PageUptodate(page))
277 goto out;
278
279 if (len == PAGE_SIZE)
280 goto out;
281
282 retval = v9fs_fid_readpage(v9inode->writeback_fid, page);
283 put_page(page);
284 if (!retval)
285 goto start;
286out:
287 *pagep = page;
288 return retval;
289}
290
291static int v9fs_write_end(struct file *filp, struct address_space *mapping,
292 loff_t pos, unsigned len, unsigned copied,
293 struct page *page, void *fsdata)
294{
295 loff_t last_pos = pos + copied;
296 struct inode *inode = page->mapping->host;
297
298 p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
299
300 if (!PageUptodate(page)) {
301 if (unlikely(copied < len)) {
302 copied = 0;
303 goto out;
304 } else if (len == PAGE_SIZE) {
305 SetPageUptodate(page);
306 }
307 }
308 /*
309 * No need to use i_size_read() here, the i_size
310 * cannot change under us because we hold the i_mutex.
311 */
312 if (last_pos > inode->i_size) {
313 inode_add_bytes(inode, last_pos - inode->i_size);
314 i_size_write(inode, last_pos);
315 }
316 set_page_dirty(page);
317out:
318 unlock_page(page);
319 put_page(page);
320
321 return copied;
322}
323
324
325const struct address_space_operations v9fs_addr_operations = {
326 .readpage = v9fs_vfs_readpage,
327 .readpages = v9fs_vfs_readpages,
328 .set_page_dirty = __set_page_dirty_nobuffers,
329 .writepage = v9fs_vfs_writepage,
330 .write_begin = v9fs_write_begin,
331 .write_end = v9fs_write_end,
332 .releasepage = v9fs_release_page,
333 .invalidatepage = v9fs_invalidate_page,
334 .launder_page = v9fs_launder_page,
335 .direct_IO = v9fs_direct_IO,
336};