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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/aio.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 int retval;
55 loff_t offset;
56 char *buffer;
57 struct inode *inode;
58
59 inode = page->mapping->host;
60 p9_debug(P9_DEBUG_VFS, "\n");
61
62 BUG_ON(!PageLocked(page));
63
64 retval = v9fs_readpage_from_fscache(inode, page);
65 if (retval == 0)
66 return retval;
67
68 buffer = kmap(page);
69 offset = page_offset(page);
70
71 retval = v9fs_fid_readn(fid, buffer, NULL, PAGE_CACHE_SIZE, offset);
72 if (retval < 0) {
73 v9fs_uncache_page(inode, page);
74 goto done;
75 }
76
77 memset(buffer + retval, 0, PAGE_CACHE_SIZE - retval);
78 flush_dcache_page(page);
79 SetPageUptodate(page);
80
81 v9fs_readpage_to_fscache(inode, page);
82 retval = 0;
83
84done:
85 kunmap(page);
86 unlock_page(page);
87 return retval;
88}
89
90
91
92
93
94
95
96
97
98static int v9fs_vfs_readpage(struct file *filp, struct page *page)
99{
100 return v9fs_fid_readpage(filp->private_data, page);
101}
102
103
104
105
106
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108
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110
111
112
113static int v9fs_vfs_readpages(struct file *filp, struct address_space *mapping,
114 struct list_head *pages, unsigned nr_pages)
115{
116 int ret = 0;
117 struct inode *inode;
118
119 inode = mapping->host;
120 p9_debug(P9_DEBUG_VFS, "inode: %p file: %p\n", inode, filp);
121
122 ret = v9fs_readpages_from_fscache(inode, mapping, pages, &nr_pages);
123 if (ret == 0)
124 return ret;
125
126 ret = read_cache_pages(mapping, pages, (void *)v9fs_vfs_readpage, filp);
127 p9_debug(P9_DEBUG_VFS, " = %d\n", ret);
128 return ret;
129}
130
131
132
133
134
135
136
137static int v9fs_release_page(struct page *page, gfp_t gfp)
138{
139 if (PagePrivate(page))
140 return 0;
141 return v9fs_fscache_release_page(page, gfp);
142}
143
144
145
146
147
148
149
150
151static void v9fs_invalidate_page(struct page *page, unsigned int offset,
152 unsigned int length)
153{
154
155
156
157
158 if (offset == 0 && length == PAGE_CACHE_SIZE)
159 v9fs_fscache_invalidate_page(page);
160}
161
162static int v9fs_vfs_writepage_locked(struct page *page)
163{
164 char *buffer;
165 int retval, len;
166 loff_t offset, size;
167 mm_segment_t old_fs;
168 struct v9fs_inode *v9inode;
169 struct inode *inode = page->mapping->host;
170
171 v9inode = V9FS_I(inode);
172 size = i_size_read(inode);
173 if (page->index == size >> PAGE_CACHE_SHIFT)
174 len = size & ~PAGE_CACHE_MASK;
175 else
176 len = PAGE_CACHE_SIZE;
177
178 set_page_writeback(page);
179
180 buffer = kmap(page);
181 offset = page_offset(page);
182
183 old_fs = get_fs();
184 set_fs(get_ds());
185
186 BUG_ON(!v9inode->writeback_fid);
187
188 retval = v9fs_file_write_internal(inode,
189 v9inode->writeback_fid,
190 (__force const char __user *)buffer,
191 len, &offset, 0);
192 if (retval > 0)
193 retval = 0;
194
195 set_fs(old_fs);
196 kunmap(page);
197 end_page_writeback(page);
198 return retval;
199}
200
201static int v9fs_vfs_writepage(struct page *page, struct writeback_control *wbc)
202{
203 int retval;
204
205 retval = v9fs_vfs_writepage_locked(page);
206 if (retval < 0) {
207 if (retval == -EAGAIN) {
208 redirty_page_for_writepage(wbc, page);
209 retval = 0;
210 } else {
211 SetPageError(page);
212 mapping_set_error(page->mapping, retval);
213 }
214 } else
215 retval = 0;
216
217 unlock_page(page);
218 return retval;
219}
220
221
222
223
224
225
226static int v9fs_launder_page(struct page *page)
227{
228 int retval;
229 struct inode *inode = page->mapping->host;
230
231 v9fs_fscache_wait_on_page_write(inode, page);
232 if (clear_page_dirty_for_io(page)) {
233 retval = v9fs_vfs_writepage_locked(page);
234 if (retval)
235 return retval;
236 }
237 return 0;
238}
239
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257
258
259static ssize_t
260v9fs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
261 loff_t pos, unsigned long nr_segs)
262{
263
264
265
266
267
268 p9_debug(P9_DEBUG_VFS, "v9fs_direct_IO: v9fs_direct_IO (%s) off/no(%lld/%lu) EINVAL\n",
269 iocb->ki_filp->f_path.dentry->d_name.name,
270 (long long)pos, nr_segs);
271
272 return -EINVAL;
273}
274
275static int v9fs_write_begin(struct file *filp, struct address_space *mapping,
276 loff_t pos, unsigned len, unsigned flags,
277 struct page **pagep, void **fsdata)
278{
279 int retval = 0;
280 struct page *page;
281 struct v9fs_inode *v9inode;
282 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
283 struct inode *inode = mapping->host;
284
285 v9inode = V9FS_I(inode);
286start:
287 page = grab_cache_page_write_begin(mapping, index, flags);
288 if (!page) {
289 retval = -ENOMEM;
290 goto out;
291 }
292 BUG_ON(!v9inode->writeback_fid);
293 if (PageUptodate(page))
294 goto out;
295
296 if (len == PAGE_CACHE_SIZE)
297 goto out;
298
299 retval = v9fs_fid_readpage(v9inode->writeback_fid, page);
300 page_cache_release(page);
301 if (!retval)
302 goto start;
303out:
304 *pagep = page;
305 return retval;
306}
307
308static int v9fs_write_end(struct file *filp, struct address_space *mapping,
309 loff_t pos, unsigned len, unsigned copied,
310 struct page *page, void *fsdata)
311{
312 loff_t last_pos = pos + copied;
313 struct inode *inode = page->mapping->host;
314
315 if (unlikely(copied < len)) {
316
317
318
319 unsigned from = pos & (PAGE_CACHE_SIZE - 1);
320
321 zero_user(page, from + copied, len - copied);
322 flush_dcache_page(page);
323 }
324
325 if (!PageUptodate(page))
326 SetPageUptodate(page);
327
328
329
330
331 if (last_pos > inode->i_size) {
332 inode_add_bytes(inode, last_pos - inode->i_size);
333 i_size_write(inode, last_pos);
334 }
335 set_page_dirty(page);
336 unlock_page(page);
337 page_cache_release(page);
338
339 return copied;
340}
341
342
343const struct address_space_operations v9fs_addr_operations = {
344 .readpage = v9fs_vfs_readpage,
345 .readpages = v9fs_vfs_readpages,
346 .set_page_dirty = __set_page_dirty_nobuffers,
347 .writepage = v9fs_vfs_writepage,
348 .write_begin = v9fs_write_begin,
349 .write_end = v9fs_write_end,
350 .releasepage = v9fs_release_page,
351 .invalidatepage = v9fs_invalidate_page,
352 .launder_page = v9fs_launder_page,
353 .direct_IO = v9fs_direct_IO,
354};
355