aboutsummaryrefslogtreecommitdiffstats
path: root/fs/afs/file.c
blob: 4975c9c193dd37505cbdcfad000fdcd24793676d (plain) (blame)
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
/* file.c: AFS filesystem file handling
 *
 * Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/pagemap.h>
#include <linux/buffer_head.h>
#include "volume.h"
#include "vnode.h"
#include <rxrpc/call.h>
#include "internal.h"

#if 0
static int afs_file_open(struct inode *inode, struct file *file);
static int afs_file_release(struct inode *inode, struct file *file);
#endif

static int afs_file_readpage(struct file *file, struct page *page);
static int afs_file_invalidatepage(struct page *page, unsigned long offset);
static int afs_file_releasepage(struct page *page, gfp_t gfp_flags);

static ssize_t afs_file_write(struct file *file, const char __user *buf,
			      size_t size, loff_t *off);

struct inode_operations afs_file_inode_operations = {
	.getattr	= afs_inode_getattr,
};

struct file_operations afs_file_file_operations = {
	.read		= generic_file_read,
	.write		= afs_file_write,
	.mmap		= generic_file_mmap,
#if 0
	.open		= afs_file_open,
	.release	= afs_file_release,
	.fsync		= afs_file_fsync,
#endif
};

struct address_space_operations afs_fs_aops = {
	.readpage	= afs_file_readpage,
	.sync_page	= block_sync_page,
	.set_page_dirty	= __set_page_dirty_nobuffers,
	.releasepage	= afs_file_releasepage,
	.invalidatepage	= afs_file_invalidatepage,
};

/*****************************************************************************/
/*
 * AFS file write
 */
static ssize_t afs_file_write(struct file *file, const char __user *buf,
			      size_t size, loff_t *off)
{
	struct afs_vnode *vnode;

	vnode = AFS_FS_I(file->f_dentry->d_inode);
	if (vnode->flags & AFS_VNODE_DELETED)
		return -ESTALE;

	return -EIO;
} /* end afs_file_write() */

/*****************************************************************************/
/*
 * deal with notification that a page was read from the cache
 */
#ifdef AFS_CACHING_SUPPORT
static void afs_file_readpage_read_complete(void *cookie_data,
					    struct page *page,
					    void *data,
					    int error)
{
	_enter("%p,%p,%p,%d", cookie_data, page, data, error);

	if (error)
		SetPageError(page);
	else
		SetPageUptodate(page);
	unlock_page(page);

} /* end afs_file_readpage_read_complete() */
#endif

/*****************************************************************************/
/*
 * deal with notification that a page was written to the cache
 */
#ifdef AFS_CACHING_SUPPORT
static void afs_file_readpage_write_complete(void *cookie_data,
					     struct page *page,
					     void *data,
					     int error)
{
	_enter("%p,%p,%p,%d", cookie_data, page, data, error);

	unlock_page(page);

} /* end afs_file_readpage_write_complete() */
#endif

/*****************************************************************************/
/*
 * AFS read page from file (or symlink)
 */
static int afs_file_readpage(struct file *file, struct page *page)
{
	struct afs_rxfs_fetch_descriptor desc;
#ifdef AFS_CACHING_SUPPORT
	struct cachefs_page *pageio;
#endif
	struct afs_vnode *vnode;
	struct inode *inode;
	int ret;

	inode = page->mapping->host;

	_enter("{%lu},{%lu}", inode->i_ino, page->index);

	vnode = AFS_FS_I(inode);

	BUG_ON(!PageLocked(page));

	ret = -ESTALE;
	if (vnode->flags & AFS_VNODE_DELETED)
		goto error;

#ifdef AFS_CACHING_SUPPORT
	ret = cachefs_page_get_private(page, &pageio, GFP_NOIO);
	if (ret < 0)
		goto error;

	/* is it cached? */
	ret = cachefs_read_or_alloc_page(vnode->cache,
					 page,
					 afs_file_readpage_read_complete,
					 NULL,
					 GFP_KERNEL);
#else
	ret = -ENOBUFS;
#endif

	switch (ret) {
		/* read BIO submitted and wb-journal entry found */
	case 1:
		BUG(); // TODO - handle wb-journal match

		/* read BIO submitted (page in cache) */
	case 0:
		break;

		/* no page available in cache */
	case -ENOBUFS:
	case -ENODATA:
	default:
		desc.fid	= vnode->fid;
		desc.offset	= page->index << PAGE_CACHE_SHIFT;
		desc.size	= min((size_t) (inode->i_size - desc.offset),
				      (size_t) PAGE_SIZE);
		desc.buffer	= kmap(page);

		clear_page(desc.buffer);

		/* read the contents of the file from the server into the
		 * page */
		ret = afs_vnode_fetch_data(vnode, &desc);
		kunmap(page);
		if (ret < 0) {
			if (ret==-ENOENT) {
				_debug("got NOENT from server"
				       " - marking file deleted and stale");
				vnode->flags |= AFS_VNODE_DELETED;
				ret = -ESTALE;
			}

#ifdef AFS_CACHING_SUPPORT
			cachefs_uncache_page(vnode->cache, page);
#endif
			goto error;
		}

		SetPageUptodate(page);

#ifdef AFS_CACHING_SUPPORT
		if (cachefs_write_page(vnode->cache,
				       page,
				       afs_file_readpage_write_complete,
				       NULL,
				       GFP_KERNEL) != 0
		    ) {
			cachefs_uncache_page(vnode->cache, page);
			unlock_page(page);
		}
#else
		unlock_page(page);
#endif
	}

	_leave(" = 0");
	return 0;

 error:
	SetPageError(page);
	unlock_page(page);

	_leave(" = %d", ret);
	return ret;

} /* end afs_file_readpage() */

/*****************************************************************************/
/*
 * get a page cookie for the specified page
 */
#ifdef AFS_CACHING_SUPPORT
int afs_cache_get_page_cookie(struct page *page,
			      struct cachefs_page **_page_cookie)
{
	int ret;

	_enter("");
	ret = cachefs_page_get_private(page,_page_cookie, GFP_NOIO);

	_leave(" = %d", ret);
	return ret;
} /* end afs_cache_get_page_cookie() */
#endif

/*****************************************************************************/
/*
 * invalidate part or all of a page
 */
static int afs_file_invalidatepage(struct page *page, unsigned long offset)
{
	int ret = 1;

	_enter("{%lu},%lu", page->index, offset);

	BUG_ON(!PageLocked(page));

	if (PagePrivate(page)) {
#ifdef AFS_CACHING_SUPPORT
		struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
		cachefs_uncache_page(vnode->cache,page);
#endif

		/* We release buffers only if the entire page is being
		 * invalidated.
		 * The get_block cached value has been unconditionally
		 * invalidated, so real IO is not possible anymore.
		 */
		if (offset == 0) {
			BUG_ON(!PageLocked(page));

			ret = 0;
			if (!PageWriteback(page))
				ret = page->mapping->a_ops->releasepage(page,
									0);
		}
	}

	_leave(" = %d", ret);
	return ret;
} /* end afs_file_invalidatepage() */

/*****************************************************************************/
/*
 * release a page and cleanup its private data
 */
static int afs_file_releasepage(struct page *page, gfp_t gfp_flags)
{
	struct cachefs_page *pageio;

	_enter("{%lu},%x", page->index, gfp_flags);

	if (PagePrivate(page)) {
#ifdef AFS_CACHING_SUPPORT
		struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
		cachefs_uncache_page(vnode->cache, page);
#endif

		pageio = (struct cachefs_page *) page_private(page);
		set_page_private(page, 0);
		ClearPagePrivate(page);

		if (pageio)
			kfree(pageio);
	}

	_leave(" = 0");
	return 0;
} /* end afs_file_releasepage() */