2
* linux/fs/9p/vfs_addr.c
4
* This file contians vfs address (mmap) ops for 9P2000.
6
* Copyright (C) 2005 by Eric Van Hensbergen <ericvh@gmail.com>
7
* Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
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.
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.
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
26
#include <linux/module.h>
27
#include <linux/errno.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>
45
* v9fs_fid_readpage - read an entire page in from 9P
47
* @fid: fid being read
48
* @page: structure to page
51
static int v9fs_fid_readpage(struct p9_fid *fid, struct page *page)
58
inode = page->mapping->host;
59
P9_DPRINTK(P9_DEBUG_VFS, "\n");
61
BUG_ON(!PageLocked(page));
63
retval = v9fs_readpage_from_fscache(inode, page);
68
offset = page_offset(page);
70
retval = v9fs_fid_readn(fid, buffer, NULL, PAGE_CACHE_SIZE, offset);
72
v9fs_uncache_page(inode, page);
76
memset(buffer + retval, 0, PAGE_CACHE_SIZE - retval);
77
flush_dcache_page(page);
78
SetPageUptodate(page);
80
v9fs_readpage_to_fscache(inode, page);
90
* v9fs_vfs_readpage - read an entire page in from 9P
92
* @filp: file being read
93
* @page: structure to page
97
static int v9fs_vfs_readpage(struct file *filp, struct page *page)
99
return v9fs_fid_readpage(filp->private_data, page);
103
* v9fs_vfs_readpages - read a set of pages from 9P
105
* @filp: file being read
106
* @mapping: the address space
107
* @pages: list of pages to read
108
* @nr_pages: count of pages to read
112
static int v9fs_vfs_readpages(struct file *filp, struct address_space *mapping,
113
struct list_head *pages, unsigned nr_pages)
118
inode = mapping->host;
119
P9_DPRINTK(P9_DEBUG_VFS, "inode: %p file: %p\n", inode, filp);
121
ret = v9fs_readpages_from_fscache(inode, mapping, pages, &nr_pages);
125
ret = read_cache_pages(mapping, pages, (void *)v9fs_vfs_readpage, filp);
126
P9_DPRINTK(P9_DEBUG_VFS, " = %d\n", ret);
131
* v9fs_release_page - release the private state associated with a page
133
* Returns 1 if the page can be released, false otherwise.
136
static int v9fs_release_page(struct page *page, gfp_t gfp)
138
if (PagePrivate(page))
140
return v9fs_fscache_release_page(page, gfp);
144
* v9fs_invalidate_page - Invalidate a page completely or partially
146
* @page: structure to page
147
* @offset: offset in the page
150
static void v9fs_invalidate_page(struct page *page, unsigned long offset)
153
* If called with zero offset, we should release
154
* the private state assocated with the page
157
v9fs_fscache_invalidate_page(page);
160
static int v9fs_vfs_writepage_locked(struct page *page)
166
struct v9fs_inode *v9inode;
167
struct inode *inode = page->mapping->host;
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;
174
len = PAGE_CACHE_SIZE;
176
set_page_writeback(page);
179
offset = page_offset(page);
183
/* We should have writeback_fid always set */
184
BUG_ON(!v9inode->writeback_fid);
186
retval = v9fs_file_write_internal(inode,
187
v9inode->writeback_fid,
188
(__force const char __user *)buffer,
195
end_page_writeback(page);
199
static int v9fs_vfs_writepage(struct page *page, struct writeback_control *wbc)
203
retval = v9fs_vfs_writepage_locked(page);
205
if (retval == -EAGAIN) {
206
redirty_page_for_writepage(wbc, page);
210
mapping_set_error(page->mapping, retval);
220
* v9fs_launder_page - Writeback a dirty page
221
* Returns 0 on success.
224
static int v9fs_launder_page(struct page *page)
227
struct inode *inode = page->mapping->host;
229
v9fs_fscache_wait_on_page_write(inode, page);
230
if (clear_page_dirty_for_io(page)) {
231
retval = v9fs_vfs_writepage_locked(page);
239
* v9fs_direct_IO - 9P address space operation for direct I/O
240
* @rw: direction (read or write)
241
* @iocb: target I/O control block
242
* @iov: array of vectors that define I/O buffer
243
* @pos: offset in file to begin the operation
244
* @nr_segs: size of iovec array
246
* The presence of v9fs_direct_IO() in the address space ops vector
247
* allowes open() O_DIRECT flags which would have failed otherwise.
249
* In the non-cached mode, we shunt off direct read and write requests before
250
* the VFS gets them, so this method should never be called.
252
* Direct IO is not 'yet' supported in the cached mode. Hence when
253
* this routine is called through generic_file_aio_read(), the read/write fails
258
v9fs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
259
loff_t pos, unsigned long nr_segs)
263
* Now that we do caching with cache mode enabled, We need
264
* to support direct IO
266
P9_DPRINTK(P9_DEBUG_VFS, "v9fs_direct_IO: v9fs_direct_IO (%s) "
267
"off/no(%lld/%lu) EINVAL\n",
268
iocb->ki_filp->f_path.dentry->d_name.name,
269
(long long) pos, nr_segs);
274
static int v9fs_write_begin(struct file *filp, struct address_space *mapping,
275
loff_t pos, unsigned len, unsigned flags,
276
struct page **pagep, void **fsdata)
280
struct v9fs_inode *v9inode;
281
pgoff_t index = pos >> PAGE_CACHE_SHIFT;
282
struct inode *inode = mapping->host;
284
v9inode = V9FS_I(inode);
286
page = grab_cache_page_write_begin(mapping, index, flags);
291
BUG_ON(!v9inode->writeback_fid);
292
if (PageUptodate(page))
295
if (len == PAGE_CACHE_SIZE)
298
retval = v9fs_fid_readpage(v9inode->writeback_fid, page);
299
page_cache_release(page);
307
static int v9fs_write_end(struct file *filp, struct address_space *mapping,
308
loff_t pos, unsigned len, unsigned copied,
309
struct page *page, void *fsdata)
311
loff_t last_pos = pos + copied;
312
struct inode *inode = page->mapping->host;
314
if (unlikely(copied < len)) {
316
* zero out the rest of the area
318
unsigned from = pos & (PAGE_CACHE_SIZE - 1);
320
zero_user(page, from + copied, len - copied);
321
flush_dcache_page(page);
324
if (!PageUptodate(page))
325
SetPageUptodate(page);
327
* No need to use i_size_read() here, the i_size
328
* cannot change under us because we hold the i_mutex.
330
if (last_pos > inode->i_size) {
331
inode_add_bytes(inode, last_pos - inode->i_size);
332
i_size_write(inode, last_pos);
334
set_page_dirty(page);
336
page_cache_release(page);
342
const struct address_space_operations v9fs_addr_operations = {
343
.readpage = v9fs_vfs_readpage,
344
.readpages = v9fs_vfs_readpages,
345
.set_page_dirty = __set_page_dirty_nobuffers,
346
.writepage = v9fs_vfs_writepage,
347
.write_begin = v9fs_write_begin,
348
.write_end = v9fs_write_end,
349
.releasepage = v9fs_release_page,
350
.invalidatepage = v9fs_invalidate_page,
351
.launder_page = v9fs_launder_page,
352
.direct_IO = v9fs_direct_IO,