xref: /openbmc/linux/fs/afs/file.c (revision d5cb9783536a41df9f9cba5b0a1d78047ed787f7)
1 /* file.c: AFS filesystem file handling
2  *
3  * Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
4  * Written by David Howells (dhowells@redhat.com)
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License
8  * as published by the Free Software Foundation; either version
9  * 2 of the License, or (at your option) any later version.
10  */
11 
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/init.h>
15 #include <linux/sched.h>
16 #include <linux/slab.h>
17 #include <linux/fs.h>
18 #include <linux/pagemap.h>
19 #include <linux/buffer_head.h>
20 #include "volume.h"
21 #include "vnode.h"
22 #include <rxrpc/call.h>
23 #include "internal.h"
24 
25 #if 0
26 static int afs_file_open(struct inode *inode, struct file *file);
27 static int afs_file_release(struct inode *inode, struct file *file);
28 #endif
29 
30 static int afs_file_readpage(struct file *file, struct page *page);
31 static int afs_file_invalidatepage(struct page *page, unsigned long offset);
32 static int afs_file_releasepage(struct page *page, gfp_t gfp_flags);
33 
34 static ssize_t afs_file_write(struct file *file, const char __user *buf,
35 			      size_t size, loff_t *off);
36 
37 struct inode_operations afs_file_inode_operations = {
38 	.getattr	= afs_inode_getattr,
39 };
40 
41 struct file_operations afs_file_file_operations = {
42 	.read		= generic_file_read,
43 	.write		= afs_file_write,
44 	.mmap		= generic_file_mmap,
45 #if 0
46 	.open		= afs_file_open,
47 	.release	= afs_file_release,
48 	.fsync		= afs_file_fsync,
49 #endif
50 };
51 
52 struct address_space_operations afs_fs_aops = {
53 	.readpage	= afs_file_readpage,
54 	.sync_page	= block_sync_page,
55 	.set_page_dirty	= __set_page_dirty_nobuffers,
56 	.releasepage	= afs_file_releasepage,
57 	.invalidatepage	= afs_file_invalidatepage,
58 };
59 
60 /*****************************************************************************/
61 /*
62  * AFS file write
63  */
64 static ssize_t afs_file_write(struct file *file, const char __user *buf,
65 			      size_t size, loff_t *off)
66 {
67 	struct afs_vnode *vnode;
68 
69 	vnode = AFS_FS_I(file->f_dentry->d_inode);
70 	if (vnode->flags & AFS_VNODE_DELETED)
71 		return -ESTALE;
72 
73 	return -EIO;
74 } /* end afs_file_write() */
75 
76 /*****************************************************************************/
77 /*
78  * deal with notification that a page was read from the cache
79  */
80 #ifdef AFS_CACHING_SUPPORT
81 static void afs_file_readpage_read_complete(void *cookie_data,
82 					    struct page *page,
83 					    void *data,
84 					    int error)
85 {
86 	_enter("%p,%p,%p,%d", cookie_data, page, data, error);
87 
88 	if (error)
89 		SetPageError(page);
90 	else
91 		SetPageUptodate(page);
92 	unlock_page(page);
93 
94 } /* end afs_file_readpage_read_complete() */
95 #endif
96 
97 /*****************************************************************************/
98 /*
99  * deal with notification that a page was written to the cache
100  */
101 #ifdef AFS_CACHING_SUPPORT
102 static void afs_file_readpage_write_complete(void *cookie_data,
103 					     struct page *page,
104 					     void *data,
105 					     int error)
106 {
107 	_enter("%p,%p,%p,%d", cookie_data, page, data, error);
108 
109 	unlock_page(page);
110 
111 } /* end afs_file_readpage_write_complete() */
112 #endif
113 
114 /*****************************************************************************/
115 /*
116  * AFS read page from file (or symlink)
117  */
118 static int afs_file_readpage(struct file *file, struct page *page)
119 {
120 	struct afs_rxfs_fetch_descriptor desc;
121 #ifdef AFS_CACHING_SUPPORT
122 	struct cachefs_page *pageio;
123 #endif
124 	struct afs_vnode *vnode;
125 	struct inode *inode;
126 	int ret;
127 
128 	inode = page->mapping->host;
129 
130 	_enter("{%lu},{%lu}", inode->i_ino, page->index);
131 
132 	vnode = AFS_FS_I(inode);
133 
134 	BUG_ON(!PageLocked(page));
135 
136 	ret = -ESTALE;
137 	if (vnode->flags & AFS_VNODE_DELETED)
138 		goto error;
139 
140 #ifdef AFS_CACHING_SUPPORT
141 	ret = cachefs_page_get_private(page, &pageio, GFP_NOIO);
142 	if (ret < 0)
143 		goto error;
144 
145 	/* is it cached? */
146 	ret = cachefs_read_or_alloc_page(vnode->cache,
147 					 page,
148 					 afs_file_readpage_read_complete,
149 					 NULL,
150 					 GFP_KERNEL);
151 #else
152 	ret = -ENOBUFS;
153 #endif
154 
155 	switch (ret) {
156 		/* read BIO submitted and wb-journal entry found */
157 	case 1:
158 		BUG(); // TODO - handle wb-journal match
159 
160 		/* read BIO submitted (page in cache) */
161 	case 0:
162 		break;
163 
164 		/* no page available in cache */
165 	case -ENOBUFS:
166 	case -ENODATA:
167 	default:
168 		desc.fid	= vnode->fid;
169 		desc.offset	= page->index << PAGE_CACHE_SHIFT;
170 		desc.size	= min((size_t) (inode->i_size - desc.offset),
171 				      (size_t) PAGE_SIZE);
172 		desc.buffer	= kmap(page);
173 
174 		clear_page(desc.buffer);
175 
176 		/* read the contents of the file from the server into the
177 		 * page */
178 		ret = afs_vnode_fetch_data(vnode, &desc);
179 		kunmap(page);
180 		if (ret < 0) {
181 			if (ret==-ENOENT) {
182 				_debug("got NOENT from server"
183 				       " - marking file deleted and stale");
184 				vnode->flags |= AFS_VNODE_DELETED;
185 				ret = -ESTALE;
186 			}
187 
188 #ifdef AFS_CACHING_SUPPORT
189 			cachefs_uncache_page(vnode->cache, page);
190 #endif
191 			goto error;
192 		}
193 
194 		SetPageUptodate(page);
195 
196 #ifdef AFS_CACHING_SUPPORT
197 		if (cachefs_write_page(vnode->cache,
198 				       page,
199 				       afs_file_readpage_write_complete,
200 				       NULL,
201 				       GFP_KERNEL) != 0
202 		    ) {
203 			cachefs_uncache_page(vnode->cache, page);
204 			unlock_page(page);
205 		}
206 #else
207 		unlock_page(page);
208 #endif
209 	}
210 
211 	_leave(" = 0");
212 	return 0;
213 
214  error:
215 	SetPageError(page);
216 	unlock_page(page);
217 
218 	_leave(" = %d", ret);
219 	return ret;
220 
221 } /* end afs_file_readpage() */
222 
223 /*****************************************************************************/
224 /*
225  * get a page cookie for the specified page
226  */
227 #ifdef AFS_CACHING_SUPPORT
228 int afs_cache_get_page_cookie(struct page *page,
229 			      struct cachefs_page **_page_cookie)
230 {
231 	int ret;
232 
233 	_enter("");
234 	ret = cachefs_page_get_private(page,_page_cookie, GFP_NOIO);
235 
236 	_leave(" = %d", ret);
237 	return ret;
238 } /* end afs_cache_get_page_cookie() */
239 #endif
240 
241 /*****************************************************************************/
242 /*
243  * invalidate part or all of a page
244  */
245 static int afs_file_invalidatepage(struct page *page, unsigned long offset)
246 {
247 	int ret = 1;
248 
249 	_enter("{%lu},%lu", page->index, offset);
250 
251 	BUG_ON(!PageLocked(page));
252 
253 	if (PagePrivate(page)) {
254 #ifdef AFS_CACHING_SUPPORT
255 		struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
256 		cachefs_uncache_page(vnode->cache,page);
257 #endif
258 
259 		/* We release buffers only if the entire page is being
260 		 * invalidated.
261 		 * The get_block cached value has been unconditionally
262 		 * invalidated, so real IO is not possible anymore.
263 		 */
264 		if (offset == 0) {
265 			BUG_ON(!PageLocked(page));
266 
267 			ret = 0;
268 			if (!PageWriteback(page))
269 				ret = page->mapping->a_ops->releasepage(page,
270 									0);
271 		}
272 	}
273 
274 	_leave(" = %d", ret);
275 	return ret;
276 } /* end afs_file_invalidatepage() */
277 
278 /*****************************************************************************/
279 /*
280  * release a page and cleanup its private data
281  */
282 static int afs_file_releasepage(struct page *page, gfp_t gfp_flags)
283 {
284 	struct cachefs_page *pageio;
285 
286 	_enter("{%lu},%x", page->index, gfp_flags);
287 
288 	if (PagePrivate(page)) {
289 #ifdef AFS_CACHING_SUPPORT
290 		struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
291 		cachefs_uncache_page(vnode->cache, page);
292 #endif
293 
294 		pageio = (struct cachefs_page *) page_private(page);
295 		set_page_private(page, 0);
296 		ClearPagePrivate(page);
297 
298 		if (pageio)
299 			kfree(pageio);
300 	}
301 
302 	_leave(" = 0");
303 	return 0;
304 } /* end afs_file_releasepage() */
305