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Eric Van Hensbergen147b31c2006-01-18 17:43:02 -08001/*
2 * linux/fs/9p/vfs_addr.c
3 *
4 * This file contians vfs address (mmap) ops for 9P2000.
5 *
6 * Copyright (C) 2005 by Eric Van Hensbergen <ericvh@gmail.com>
7 * Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
8 *
9 * This program is free software; you can redistribute it and/or modify
Eric Van Hensbergen42e8c502006-03-25 03:07:28 -080010 * it under the terms of the GNU General Public License version 2
11 * as published by the Free Software Foundation.
Eric Van Hensbergen147b31c2006-01-18 17:43:02 -080012 *
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.
17 *
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
23 *
24 */
25
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>
Eric Van Hensbergen147b31c2006-01-18 17:43:02 -080032#include <linux/inet.h>
Eric Van Hensbergen147b31c2006-01-18 17:43:02 -080033#include <linux/pagemap.h>
34#include <linux/idr.h>
Alexey Dobriyane8edc6e2007-05-21 01:22:52 +040035#include <linux/sched.h>
Latchesar Ionkovbd238fb2007-07-10 17:57:28 -050036#include <net/9p/9p.h>
37#include <net/9p/client.h>
Eric Van Hensbergen147b31c2006-01-18 17:43:02 -080038
Eric Van Hensbergen147b31c2006-01-18 17:43:02 -080039#include "v9fs.h"
Eric Van Hensbergen147b31c2006-01-18 17:43:02 -080040#include "v9fs_vfs.h"
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -050041#include "cache.h"
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +053042#include "fid.h"
Eric Van Hensbergen147b31c2006-01-18 17:43:02 -080043
44/**
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +053045 * v9fs_fid_readpage - read an entire page in from 9P
Eric Van Hensbergen147b31c2006-01-18 17:43:02 -080046 *
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +053047 * @fid: fid being read
Eric Van Hensbergen147b31c2006-01-18 17:43:02 -080048 * @page: structure to page
49 *
50 */
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +053051static int v9fs_fid_readpage(struct p9_fid *fid, struct page *page)
Eric Van Hensbergen147b31c2006-01-18 17:43:02 -080052{
Latchesar Ionkovbd238fb2007-07-10 17:57:28 -050053 int retval;
54 loff_t offset;
55 char *buffer;
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -050056 struct inode *inode;
Eric Van Hensbergen147b31c2006-01-18 17:43:02 -080057
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -050058 inode = page->mapping->host;
Latchesar Ionkovbd238fb2007-07-10 17:57:28 -050059 P9_DPRINTK(P9_DEBUG_VFS, "\n");
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -050060
61 BUG_ON(!PageLocked(page));
62
63 retval = v9fs_readpage_from_fscache(inode, page);
64 if (retval == 0)
65 return retval;
66
Eric Van Hensbergen147b31c2006-01-18 17:43:02 -080067 buffer = kmap(page);
Latchesar Ionkovbd238fb2007-07-10 17:57:28 -050068 offset = page_offset(page);
Eric Van Hensbergen147b31c2006-01-18 17:43:02 -080069
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +053070 retval = v9fs_fid_readn(fid, buffer, NULL, PAGE_CACHE_SIZE, offset);
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -050071 if (retval < 0) {
72 v9fs_uncache_page(inode, page);
Latchesar Ionkovbd238fb2007-07-10 17:57:28 -050073 goto done;
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -050074 }
Eric Van Hensbergen147b31c2006-01-18 17:43:02 -080075
Latchesar Ionkovbd238fb2007-07-10 17:57:28 -050076 memset(buffer + retval, 0, PAGE_CACHE_SIZE - retval);
Eric Van Hensbergen147b31c2006-01-18 17:43:02 -080077 flush_dcache_page(page);
78 SetPageUptodate(page);
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -050079
80 v9fs_readpage_to_fscache(inode, page);
Eric Van Hensbergen147b31c2006-01-18 17:43:02 -080081 retval = 0;
82
Latchesar Ionkovbd238fb2007-07-10 17:57:28 -050083done:
Eric Van Hensbergen147b31c2006-01-18 17:43:02 -080084 kunmap(page);
85 unlock_page(page);
86 return retval;
87}
88
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -050089/**
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +053090 * v9fs_vfs_readpage - read an entire page in from 9P
91 *
92 * @filp: file being read
93 * @page: structure to page
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/**
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500103 * v9fs_vfs_readpages - read a set of pages from 9P
104 *
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
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_DPRINTK(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_DPRINTK(P9_DEBUG_VFS, " = %d\n", ret);
127 return ret;
128}
129
130/**
131 * v9fs_release_page - release the private state associated with a page
132 *
133 * Returns 1 if the page can be released, false otherwise.
134 */
135
136static int v9fs_release_page(struct page *page, gfp_t gfp)
137{
138 if (PagePrivate(page))
139 return 0;
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500140 return v9fs_fscache_release_page(page, gfp);
141}
142
143/**
144 * v9fs_invalidate_page - Invalidate a page completely or partially
145 *
146 * @page: structure to page
147 * @offset: offset in the page
148 */
149
150static void v9fs_invalidate_page(struct page *page, unsigned long offset)
151{
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530152 /*
153 * If called with zero offset, we should release
154 * the private state assocated with the page
155 */
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500156 if (offset == 0)
157 v9fs_fscache_invalidate_page(page);
158}
159
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530160static 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;
Aneesh Kumar K.V6b39f6d2011-02-28 17:04:03 +0530166 struct v9fs_inode *v9inode;
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530167 struct inode *inode = page->mapping->host;
168
Aneesh Kumar K.V6b39f6d2011-02-28 17:04:03 +0530169 v9inode = V9FS_I(inode);
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530170 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());
Aneesh Kumar K.V6b39f6d2011-02-28 17:04:03 +0530183 /* We should have writeback_fid always set */
184 BUG_ON(!v9inode->writeback_fid);
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530185
186 retval = v9fs_file_write_internal(inode,
Aneesh Kumar K.V6b39f6d2011-02-28 17:04:03 +0530187 v9inode->writeback_fid,
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530188 (__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
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500219/**
220 * v9fs_launder_page - Writeback a dirty page
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500221 * Returns 0 on success.
222 */
223
224static int v9fs_launder_page(struct page *page)
225{
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530226 int retval;
Aneesh Kumar K.V2efda792011-02-28 17:03:56 +0530227 struct inode *inode = page->mapping->host;
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530228
Aneesh Kumar K.V2efda792011-02-28 17:03:56 +0530229 v9fs_fscache_wait_on_page_write(inode, page);
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530230 if (clear_page_dirty_for_io(page)) {
231 retval = v9fs_vfs_writepage_locked(page);
232 if (retval)
233 return retval;
234 }
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500235 return 0;
236}
237
jvrao3e24ad22010-08-24 15:43:28 +0000238/**
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
245 *
246 * The presence of v9fs_direct_IO() in the address space ops vector
247 * allowes open() O_DIRECT flags which would have failed otherwise.
248 *
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.
251 *
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
254 * with an error.
255 *
256 */
Aneesh Kumar K.Ve959b542011-02-28 17:04:04 +0530257static ssize_t
258v9fs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
259 loff_t pos, unsigned long nr_segs)
jvrao3e24ad22010-08-24 15:43:28 +0000260{
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530261 /*
262 * FIXME
263 * Now that we do caching with cache mode enabled, We need
264 * to support direct IO
265 */
jvrao3e24ad22010-08-24 15:43:28 +0000266 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);
270
271 return -EINVAL;
272}
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530273
274static 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)
277{
278 int retval = 0;
279 struct page *page;
Aneesh Kumar K.V6b39f6d2011-02-28 17:04:03 +0530280 struct v9fs_inode *v9inode;
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530281 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
282 struct inode *inode = mapping->host;
283
Aneesh Kumar K.V6b39f6d2011-02-28 17:04:03 +0530284 v9inode = V9FS_I(inode);
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530285start:
286 page = grab_cache_page_write_begin(mapping, index, flags);
287 if (!page) {
288 retval = -ENOMEM;
289 goto out;
290 }
Aneesh Kumar K.V6b39f6d2011-02-28 17:04:03 +0530291 BUG_ON(!v9inode->writeback_fid);
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530292 if (PageUptodate(page))
293 goto out;
294
295 if (len == PAGE_CACHE_SIZE)
296 goto out;
297
Aneesh Kumar K.V6b39f6d2011-02-28 17:04:03 +0530298 retval = v9fs_fid_readpage(v9inode->writeback_fid, page);
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530299 page_cache_release(page);
300 if (!retval)
301 goto start;
302out:
303 *pagep = page;
304 return retval;
305}
306
307static 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)
310{
311 loff_t last_pos = pos + copied;
312 struct inode *inode = page->mapping->host;
313
314 if (unlikely(copied < len)) {
315 /*
316 * zero out the rest of the area
317 */
318 unsigned from = pos & (PAGE_CACHE_SIZE - 1);
319
320 zero_user(page, from + copied, len - copied);
321 flush_dcache_page(page);
322 }
323
324 if (!PageUptodate(page))
325 SetPageUptodate(page);
326 /*
327 * No need to use i_size_read() here, the i_size
328 * cannot change under us because we hold the i_mutex.
329 */
330 if (last_pos > inode->i_size) {
331 inode_add_bytes(inode, last_pos - inode->i_size);
332 i_size_write(inode, last_pos);
333 }
334 set_page_dirty(page);
335 unlock_page(page);
336 page_cache_release(page);
337
338 return copied;
339}
340
341
Christoph Hellwigf5e54d62006-06-28 04:26:44 -0700342const struct address_space_operations v9fs_addr_operations = {
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530343 .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,
Eric Van Hensbergen147b31c2006-01-18 17:43:02 -0800353};