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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
47
48
49
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
90
91
92
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
103
104
105
106
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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
131
132
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
144
145
146
147
148
149static void v9fs_invalidate_page(struct page *page, unsigned int offset,
150 unsigned int length)
151{
152
153
154
155
156 if (offset == 0 && length == PAGE_CACHE_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_CACHE_SHIFT)
170 len = size & ~PAGE_CACHE_MASK;
171 else
172 len = PAGE_CACHE_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
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
214
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
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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_CACHE_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_CACHE_SIZE)
292 goto out;
293
294 retval = v9fs_fid_readpage(v9inode->writeback_fid, page);
295 page_cache_release(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
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
326
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
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};
352