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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 <net/9p/9p.h>
37#include <net/9p/client.h>
38
39#include "v9fs.h"
40#include "v9fs_vfs.h"
41#include "cache.h"
42#include "fid.h"
43
44
45
46
47
48
49
50
51static int v9fs_fid_readpage(struct p9_fid *fid, struct page *page)
52{
53 int retval;
54 loff_t offset;
55 char *buffer;
56 struct inode *inode;
57
58 inode = page->mapping->host;
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 buffer = kmap(page);
68 offset = page_offset(page);
69
70 retval = v9fs_fid_readn(fid, buffer, NULL, PAGE_CACHE_SIZE, offset);
71 if (retval < 0) {
72 v9fs_uncache_page(inode, page);
73 goto done;
74 }
75
76 memset(buffer + retval, 0, PAGE_CACHE_SIZE - retval);
77 flush_dcache_page(page);
78 SetPageUptodate(page);
79
80 v9fs_readpage_to_fscache(inode, page);
81 retval = 0;
82
83done:
84 kunmap(page);
85 unlock_page(page);
86 return retval;
87}
88
89
90
91
92
93
94
95
96
97static int v9fs_vfs_readpage(struct file *filp, struct page *page)
98{
99 return v9fs_fid_readpage(filp->private_data, page);
100}
101
102
103
104
105
106
107
108
109
110
111
112static int v9fs_vfs_readpages(struct file *filp, struct address_space *mapping,
113 struct list_head *pages, unsigned nr_pages)
114{
115 int ret = 0;
116 struct inode *inode;
117
118 inode = mapping->host;
119 p9_debug(P9_DEBUG_VFS, "inode: %p file: %p\n", inode, filp);
120
121 ret = v9fs_readpages_from_fscache(inode, mapping, pages, &nr_pages);
122 if (ret == 0)
123 return ret;
124
125 ret = read_cache_pages(mapping, pages, (void *)v9fs_vfs_readpage, filp);
126 p9_debug(P9_DEBUG_VFS, " = %d\n", ret);
127 return ret;
128}
129
130
131
132
133
134
135
136static int v9fs_release_page(struct page *page, gfp_t gfp)
137{
138 if (PagePrivate(page))
139 return 0;
140 return v9fs_fscache_release_page(page, gfp);
141}
142
143
144
145
146
147
148
149
150static void v9fs_invalidate_page(struct page *page, unsigned long offset)
151{
152
153
154
155
156 if (offset == 0)
157 v9fs_fscache_invalidate_page(page);
158}
159
160static int v9fs_vfs_writepage_locked(struct page *page)
161{
162 char *buffer;
163 int retval, len;
164 loff_t offset, size;
165 mm_segment_t old_fs;
166 struct v9fs_inode *v9inode;
167 struct inode *inode = page->mapping->host;
168
169 v9inode = V9FS_I(inode);
170 size = i_size_read(inode);
171 if (page->index == size >> PAGE_CACHE_SHIFT)
172 len = size & ~PAGE_CACHE_MASK;
173 else
174 len = PAGE_CACHE_SIZE;
175
176 set_page_writeback(page);
177
178 buffer = kmap(page);
179 offset = page_offset(page);
180
181 old_fs = get_fs();
182 set_fs(get_ds());
183
184 BUG_ON(!v9inode->writeback_fid);
185
186 retval = v9fs_file_write_internal(inode,
187 v9inode->writeback_fid,
188 (__force const char __user *)buffer,
189 len, &offset, 0);
190 if (retval > 0)
191 retval = 0;
192
193 set_fs(old_fs);
194 kunmap(page);
195 end_page_writeback(page);
196 return retval;
197}
198
199static int v9fs_vfs_writepage(struct page *page, struct writeback_control *wbc)
200{
201 int retval;
202
203 retval = v9fs_vfs_writepage_locked(page);
204 if (retval < 0) {
205 if (retval == -EAGAIN) {
206 redirty_page_for_writepage(wbc, page);
207 retval = 0;
208 } else {
209 SetPageError(page);
210 mapping_set_error(page->mapping, retval);
211 }
212 } else
213 retval = 0;
214
215 unlock_page(page);
216 return retval;
217}
218
219
220
221
222
223
224static int v9fs_launder_page(struct page *page)
225{
226 int retval;
227 struct inode *inode = page->mapping->host;
228
229 v9fs_fscache_wait_on_page_write(inode, page);
230 if (clear_page_dirty_for_io(page)) {
231 retval = v9fs_vfs_writepage_locked(page);
232 if (retval)
233 return retval;
234 }
235 return 0;
236}
237
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256
257static ssize_t
258v9fs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
259 loff_t pos, unsigned long nr_segs)
260{
261
262
263
264
265
266 p9_debug(P9_DEBUG_VFS, "v9fs_direct_IO: v9fs_direct_IO (%s) off/no(%lld/%lu) EINVAL\n",
267 iocb->ki_filp->f_path.dentry->d_name.name,
268 (long long)pos, nr_segs);
269
270 return -EINVAL;
271}
272
273static int v9fs_write_begin(struct file *filp, struct address_space *mapping,
274 loff_t pos, unsigned len, unsigned flags,
275 struct page **pagep, void **fsdata)
276{
277 int retval = 0;
278 struct page *page;
279 struct v9fs_inode *v9inode;
280 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
281 struct inode *inode = mapping->host;
282
283 v9inode = V9FS_I(inode);
284start:
285 page = grab_cache_page_write_begin(mapping, index, flags);
286 if (!page) {
287 retval = -ENOMEM;
288 goto out;
289 }
290 BUG_ON(!v9inode->writeback_fid);
291 if (PageUptodate(page))
292 goto out;
293
294 if (len == PAGE_CACHE_SIZE)
295 goto out;
296
297 retval = v9fs_fid_readpage(v9inode->writeback_fid, page);
298 page_cache_release(page);
299 if (!retval)
300 goto start;
301out:
302 *pagep = page;
303 return retval;
304}
305
306static int v9fs_write_end(struct file *filp, struct address_space *mapping,
307 loff_t pos, unsigned len, unsigned copied,
308 struct page *page, void *fsdata)
309{
310 loff_t last_pos = pos + copied;
311 struct inode *inode = page->mapping->host;
312
313 if (unlikely(copied < len)) {
314
315
316
317 unsigned from = pos & (PAGE_CACHE_SIZE - 1);
318
319 zero_user(page, from + copied, len - copied);
320 flush_dcache_page(page);
321 }
322
323 if (!PageUptodate(page))
324 SetPageUptodate(page);
325
326
327
328
329 if (last_pos > inode->i_size) {
330 inode_add_bytes(inode, last_pos - inode->i_size);
331 i_size_write(inode, last_pos);
332 }
333 set_page_dirty(page);
334 unlock_page(page);
335 page_cache_release(page);
336
337 return copied;
338}
339
340
341const struct address_space_operations v9fs_addr_operations = {
342 .readpage = v9fs_vfs_readpage,
343 .readpages = v9fs_vfs_readpages,
344 .set_page_dirty = __set_page_dirty_nobuffers,
345 .writepage = v9fs_vfs_writepage,
346 .write_begin = v9fs_write_begin,
347 .write_end = v9fs_write_end,
348 .releasepage = v9fs_release_page,
349 .invalidatepage = v9fs_invalidate_page,
350 .launder_page = v9fs_launder_page,
351 .direct_IO = v9fs_direct_IO,
352};
353