summaryrefslogtreecommitdiffstats
path: root/fs/9p/vfs_addr.c
blob: ee455526ca5b9f3ba9567e6cbfcdd208b203a9c6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
/*
 *  linux/fs/9p/vfs_addr.c
 *
 * This file contians vfs address (mmap) ops for 9P2000.
 *
 *  Copyright (C) 2005 by Eric Van Hensbergen <ericvh@gmail.com>
 *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2
 *  as published by the Free Software Foundation.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to:
 *  Free Software Foundation
 *  51 Franklin Street, Fifth Floor
 *  Boston, MA  02111-1301  USA
 *
 */

#include <linux/module.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/stat.h>
#include <linux/string.h>
#include <linux/inet.h>
#include <linux/pagemap.h>
#include <linux/idr.h>
#include <linux/sched.h>
#include <net/9p/9p.h>
#include <net/9p/client.h>

#include "v9fs.h"
#include "v9fs_vfs.h"
#include "cache.h"
#include "fid.h"

/**
 * v9fs_fid_readpage - read an entire page in from 9P
 *
 * @fid: fid being read
 * @page: structure to page
 *
 */
static int v9fs_fid_readpage(struct p9_fid *fid, struct page *page)
{
	int retval;
	loff_t offset;
	char *buffer;
	struct inode *inode;

	inode = page->mapping->host;
	P9_DPRINTK(P9_DEBUG_VFS, "\n");

	BUG_ON(!PageLocked(page));

	retval = v9fs_readpage_from_fscache(inode, page);
	if (retval == 0)
		return retval;

	buffer = kmap(page);
	offset = page_offset(page);

	retval = v9fs_fid_readn(fid, buffer, NULL, PAGE_CACHE_SIZE, offset);
	if (retval < 0) {
		v9fs_uncache_page(inode, page);
		goto done;
	}

	memset(buffer + retval, 0, PAGE_CACHE_SIZE - retval);
	flush_dcache_page(page);
	SetPageUptodate(page);

	v9fs_readpage_to_fscache(inode, page);
	retval = 0;

done:
	kunmap(page);
	unlock_page(page);
	return retval;
}

/**
 * v9fs_vfs_readpage - read an entire page in from 9P
 *
 * @filp: file being read
 * @page: structure to page
 *
 */

static int v9fs_vfs_readpage(struct file *filp, struct page *page)
{
	return v9fs_fid_readpage(filp->private_data, page);
}

/**
 * v9fs_vfs_readpages - read a set of pages from 9P
 *
 * @filp: file being read
 * @mapping: the address space
 * @pages: list of pages to read
 * @nr_pages: count of pages to read
 *
 */

static int v9fs_vfs_readpages(struct file *filp, struct address_space *mapping,
			     struct list_head *pages, unsigned nr_pages)
{
	int ret = 0;
	struct inode *inode;

	inode = mapping->host;
	P9_DPRINTK(P9_DEBUG_VFS, "inode: %p file: %p\n", inode, filp);

	ret = v9fs_readpages_from_fscache(inode, mapping, pages, &nr_pages);
	if (ret == 0)
		return ret;

	ret = read_cache_pages(mapping, pages, (void *)v9fs_vfs_readpage, filp);
	P9_DPRINTK(P9_DEBUG_VFS, "  = %d\n", ret);
	return ret;
}

/**
 * v9fs_release_page - release the private state associated with a page
 *
 * Returns 1 if the page can be released, false otherwise.
 */

static int v9fs_release_page(struct page *page, gfp_t gfp)
{
	if (PagePrivate(page))
		return 0;
	return v9fs_fscache_release_page(page, gfp);
}

/**
 * v9fs_invalidate_page - Invalidate a page completely or partially
 *
 * @page: structure to page
 * @offset: offset in the page
 */

static void v9fs_invalidate_page(struct page *page, unsigned long offset)
{
	/*
	 * If called with zero offset, we should release
	 * the private state assocated with the page
	 */
	if (offset == 0)
		v9fs_fscache_invalidate_page(page);
}

static int v9fs_vfs_writepage_locked(struct page *page)
{
	char *buffer;
	int retval, len;
	loff_t offset, size;
	mm_segment_t old_fs;
	struct v9fs_inode *v9inode;
	struct inode *inode = page->mapping->host;

	v9inode = V9FS_I(inode);
	size = i_size_read(inode);
	if (page->index == size >> PAGE_CACHE_SHIFT)
		len = size & ~PAGE_CACHE_MASK;
	else
		len = PAGE_CACHE_SIZE;

	set_page_writeback(page);

	buffer = kmap(page);
	offset = page_offset(page);

	old_fs = get_fs();
	set_fs(get_ds());
	/* We should have writeback_fid always set */
	BUG_ON(!v9inode->writeback_fid);

	retval = v9fs_file_write_internal(inode,
					  v9inode->writeback_fid,
					  (__force const char __user *)buffer,
					  len, &offset, 0);
	if (retval > 0)
		retval = 0;

	set_fs(old_fs);
	kunmap(page);
	end_page_writeback(page);
	return retval;
}

static int v9fs_vfs_writepage(struct page *page, struct writeback_control *wbc)
{
	int retval;

	retval = v9fs_vfs_writepage_locked(page);
	if (retval < 0) {
		if (retval == -EAGAIN) {
			redirty_page_for_writepage(wbc, page);
			retval = 0;
		} else {
			SetPageError(page);
			mapping_set_error(page->mapping, retval);
		}
	} else
		retval = 0;

	unlock_page(page);
	return retval;
}

/**
 * v9fs_launder_page - Writeback a dirty page
 * Returns 0 on success.
 */

static int v9fs_launder_page(struct page *page)
{
	int retval;
	struct inode *inode = page->mapping->host;

	v9fs_fscache_wait_on_page_write(inode, page);
	if (clear_page_dirty_for_io(page)) {
		retval = v9fs_vfs_writepage_locked(page);
		if (retval)
			return retval;
	}
	return 0;
}

/**
 * v9fs_direct_IO - 9P address space operation for direct I/O
 * @rw: direction (read or write)
 * @iocb: target I/O control block
 * @iov: array of vectors that define I/O buffer
 * @pos: offset in file to begin the operation
 * @nr_segs: size of iovec array
 *
 * The presence of v9fs_direct_IO() in the address space ops vector
 * allowes open() O_DIRECT flags which would have failed otherwise.
 *
 * In the non-cached mode, we shunt off direct read and write requests before
 * the VFS gets them, so this method should never be called.
 *
 * Direct IO is not 'yet' supported in the cached mode. Hence when
 * this routine is called through generic_file_aio_read(), the read/write fails
 * with an error.
 *
 */
ssize_t v9fs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
		loff_t pos, unsigned long nr_segs)
{
	/*
	 * FIXME
	 * Now that we do caching with cache mode enabled, We need
	 * to support direct IO
	 */
	P9_DPRINTK(P9_DEBUG_VFS, "v9fs_direct_IO: v9fs_direct_IO (%s) "
			"off/no(%lld/%lu) EINVAL\n",
			iocb->ki_filp->f_path.dentry->d_name.name,
			(long long) pos, nr_segs);

	return -EINVAL;
}

static int v9fs_write_begin(struct file *filp, struct address_space *mapping,
			    loff_t pos, unsigned len, unsigned flags,
			    struct page **pagep, void **fsdata)
{
	int retval = 0;
	struct page *page;
	struct v9fs_inode *v9inode;
	pgoff_t index = pos >> PAGE_CACHE_SHIFT;
	struct inode *inode = mapping->host;

	v9inode = V9FS_I(inode);
start:
	page = grab_cache_page_write_begin(mapping, index, flags);
	if (!page) {
		retval = -ENOMEM;
		goto out;
	}
	BUG_ON(!v9inode->writeback_fid);
	if (PageUptodate(page))
		goto out;

	if (len == PAGE_CACHE_SIZE)
		goto out;

	retval = v9fs_fid_readpage(v9inode->writeback_fid, page);
	page_cache_release(page);
	if (!retval)
		goto start;
out:
	*pagep = page;
	return retval;
}

static int v9fs_write_end(struct file *filp, struct address_space *mapping,
			  loff_t pos, unsigned len, unsigned copied,
			  struct page *page, void *fsdata)
{
	loff_t last_pos = pos + copied;
	struct inode *inode = page->mapping->host;

	if (unlikely(copied < len)) {
		/*
		 * zero out the rest of the area
		 */
		unsigned from = pos & (PAGE_CACHE_SIZE - 1);

		zero_user(page, from + copied, len - copied);
		flush_dcache_page(page);
	}

	if (!PageUptodate(page))
		SetPageUptodate(page);
	/*
	 * No need to use i_size_read() here, the i_size
	 * cannot change under us because we hold the i_mutex.
	 */
	if (last_pos > inode->i_size) {
		inode_add_bytes(inode, last_pos - inode->i_size);
		i_size_write(inode, last_pos);
	}
	set_page_dirty(page);
	unlock_page(page);
	page_cache_release(page);

	return copied;
}


const struct address_space_operations v9fs_addr_operations = {
	.readpage = v9fs_vfs_readpage,
	.readpages = v9fs_vfs_readpages,
	.set_page_dirty = __set_page_dirty_nobuffers,
	.writepage = v9fs_vfs_writepage,
	.write_begin = v9fs_write_begin,
	.write_end = v9fs_write_end,
	.releasepage = v9fs_release_page,
	.invalidatepage = v9fs_invalidate_page,
	.launder_page = v9fs_launder_page,
	.direct_IO = v9fs_direct_IO,
};
OpenPOWER on IntegriCloud