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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>
Kent Overstreeta27bb332013-05-07 16:19:08 -070036#include <linux/aio.h>
Latchesar Ionkovbd238fb2007-07-10 17:57:28 -050037#include <net/9p/9p.h>
38#include <net/9p/client.h>
Eric Van Hensbergen147b31c2006-01-18 17:43:02 -080039
Eric Van Hensbergen147b31c2006-01-18 17:43:02 -080040#include "v9fs.h"
Eric Van Hensbergen147b31c2006-01-18 17:43:02 -080041#include "v9fs_vfs.h"
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -050042#include "cache.h"
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +053043#include "fid.h"
Eric Van Hensbergen147b31c2006-01-18 17:43:02 -080044
45/**
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +053046 * v9fs_fid_readpage - read an entire page in from 9P
Eric Van Hensbergen147b31c2006-01-18 17:43:02 -080047 *
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +053048 * @fid: fid being read
Eric Van Hensbergen147b31c2006-01-18 17:43:02 -080049 * @page: structure to page
50 *
51 */
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +053052static int v9fs_fid_readpage(struct p9_fid *fid, struct page *page)
Eric Van Hensbergen147b31c2006-01-18 17:43:02 -080053{
Latchesar Ionkovbd238fb2007-07-10 17:57:28 -050054 int retval;
55 loff_t offset;
56 char *buffer;
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -050057 struct inode *inode;
Eric Van Hensbergen147b31c2006-01-18 17:43:02 -080058
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -050059 inode = page->mapping->host;
Joe Perches5d385152011-11-28 10:40:46 -080060 p9_debug(P9_DEBUG_VFS, "\n");
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -050061
62 BUG_ON(!PageLocked(page));
63
64 retval = v9fs_readpage_from_fscache(inode, page);
65 if (retval == 0)
66 return retval;
67
Eric Van Hensbergen147b31c2006-01-18 17:43:02 -080068 buffer = kmap(page);
Latchesar Ionkovbd238fb2007-07-10 17:57:28 -050069 offset = page_offset(page);
Eric Van Hensbergen147b31c2006-01-18 17:43:02 -080070
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +053071 retval = v9fs_fid_readn(fid, buffer, NULL, PAGE_CACHE_SIZE, offset);
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -050072 if (retval < 0) {
73 v9fs_uncache_page(inode, page);
Latchesar Ionkovbd238fb2007-07-10 17:57:28 -050074 goto done;
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -050075 }
Eric Van Hensbergen147b31c2006-01-18 17:43:02 -080076
Latchesar Ionkovbd238fb2007-07-10 17:57:28 -050077 memset(buffer + retval, 0, PAGE_CACHE_SIZE - retval);
Eric Van Hensbergen147b31c2006-01-18 17:43:02 -080078 flush_dcache_page(page);
79 SetPageUptodate(page);
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -050080
81 v9fs_readpage_to_fscache(inode, page);
Eric Van Hensbergen147b31c2006-01-18 17:43:02 -080082 retval = 0;
83
Latchesar Ionkovbd238fb2007-07-10 17:57:28 -050084done:
Eric Van Hensbergen147b31c2006-01-18 17:43:02 -080085 kunmap(page);
86 unlock_page(page);
87 return retval;
88}
89
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -050090/**
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +053091 * v9fs_vfs_readpage - read an entire page in from 9P
92 *
93 * @filp: file being read
94 * @page: structure to page
95 *
96 */
97
98static int v9fs_vfs_readpage(struct file *filp, struct page *page)
99{
100 return v9fs_fid_readpage(filp->private_data, page);
101}
102
103/**
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500104 * v9fs_vfs_readpages - read a set of pages from 9P
105 *
106 * @filp: file being read
107 * @mapping: the address space
108 * @pages: list of pages to read
109 * @nr_pages: count of pages to read
110 *
111 */
112
113static int v9fs_vfs_readpages(struct file *filp, struct address_space *mapping,
114 struct list_head *pages, unsigned nr_pages)
115{
116 int ret = 0;
117 struct inode *inode;
118
119 inode = mapping->host;
Joe Perches5d385152011-11-28 10:40:46 -0800120 p9_debug(P9_DEBUG_VFS, "inode: %p file: %p\n", inode, filp);
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500121
122 ret = v9fs_readpages_from_fscache(inode, mapping, pages, &nr_pages);
123 if (ret == 0)
124 return ret;
125
126 ret = read_cache_pages(mapping, pages, (void *)v9fs_vfs_readpage, filp);
Joe Perches5d385152011-11-28 10:40:46 -0800127 p9_debug(P9_DEBUG_VFS, " = %d\n", ret);
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500128 return ret;
129}
130
131/**
132 * v9fs_release_page - release the private state associated with a page
133 *
134 * Returns 1 if the page can be released, false otherwise.
135 */
136
137static int v9fs_release_page(struct page *page, gfp_t gfp)
138{
139 if (PagePrivate(page))
140 return 0;
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500141 return v9fs_fscache_release_page(page, gfp);
142}
143
144/**
145 * v9fs_invalidate_page - Invalidate a page completely or partially
146 *
147 * @page: structure to page
148 * @offset: offset in the page
149 */
150
Lukas Czernerd47992f2013-05-21 23:17:23 -0400151static void v9fs_invalidate_page(struct page *page, unsigned int offset,
152 unsigned int length)
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500153{
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530154 /*
155 * If called with zero offset, we should release
156 * the private state assocated with the page
157 */
Lukas Czernerd47992f2013-05-21 23:17:23 -0400158 if (offset == 0 && length == PAGE_CACHE_SIZE)
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500159 v9fs_fscache_invalidate_page(page);
160}
161
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530162static int v9fs_vfs_writepage_locked(struct page *page)
163{
164 char *buffer;
165 int retval, len;
166 loff_t offset, size;
167 mm_segment_t old_fs;
Aneesh Kumar K.V6b39f6d2011-02-28 17:04:03 +0530168 struct v9fs_inode *v9inode;
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530169 struct inode *inode = page->mapping->host;
170
Aneesh Kumar K.V6b39f6d2011-02-28 17:04:03 +0530171 v9inode = V9FS_I(inode);
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530172 size = i_size_read(inode);
173 if (page->index == size >> PAGE_CACHE_SHIFT)
174 len = size & ~PAGE_CACHE_MASK;
175 else
176 len = PAGE_CACHE_SIZE;
177
178 set_page_writeback(page);
179
180 buffer = kmap(page);
181 offset = page_offset(page);
182
183 old_fs = get_fs();
184 set_fs(get_ds());
Aneesh Kumar K.V6b39f6d2011-02-28 17:04:03 +0530185 /* We should have writeback_fid always set */
186 BUG_ON(!v9inode->writeback_fid);
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530187
188 retval = v9fs_file_write_internal(inode,
Aneesh Kumar K.V6b39f6d2011-02-28 17:04:03 +0530189 v9inode->writeback_fid,
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530190 (__force const char __user *)buffer,
191 len, &offset, 0);
192 if (retval > 0)
193 retval = 0;
194
195 set_fs(old_fs);
196 kunmap(page);
197 end_page_writeback(page);
198 return retval;
199}
200
201static int v9fs_vfs_writepage(struct page *page, struct writeback_control *wbc)
202{
203 int retval;
204
Dominique Martinetfb89b452014-01-10 13:44:09 +0100205 p9_debug(P9_DEBUG_VFS, "page %p\n", page);
206
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530207 retval = v9fs_vfs_writepage_locked(page);
208 if (retval < 0) {
209 if (retval == -EAGAIN) {
210 redirty_page_for_writepage(wbc, page);
211 retval = 0;
212 } else {
213 SetPageError(page);
214 mapping_set_error(page->mapping, retval);
215 }
216 } else
217 retval = 0;
218
219 unlock_page(page);
220 return retval;
221}
222
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500223/**
224 * v9fs_launder_page - Writeback a dirty page
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500225 * Returns 0 on success.
226 */
227
228static int v9fs_launder_page(struct page *page)
229{
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530230 int retval;
Aneesh Kumar K.V2efda792011-02-28 17:03:56 +0530231 struct inode *inode = page->mapping->host;
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530232
Aneesh Kumar K.V2efda792011-02-28 17:03:56 +0530233 v9fs_fscache_wait_on_page_write(inode, page);
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530234 if (clear_page_dirty_for_io(page)) {
235 retval = v9fs_vfs_writepage_locked(page);
236 if (retval)
237 return retval;
238 }
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500239 return 0;
240}
241
jvrao3e24ad22010-08-24 15:43:28 +0000242/**
243 * v9fs_direct_IO - 9P address space operation for direct I/O
244 * @rw: direction (read or write)
245 * @iocb: target I/O control block
246 * @iov: array of vectors that define I/O buffer
247 * @pos: offset in file to begin the operation
248 * @nr_segs: size of iovec array
249 *
250 * The presence of v9fs_direct_IO() in the address space ops vector
251 * allowes open() O_DIRECT flags which would have failed otherwise.
252 *
253 * In the non-cached mode, we shunt off direct read and write requests before
254 * the VFS gets them, so this method should never be called.
255 *
256 * Direct IO is not 'yet' supported in the cached mode. Hence when
257 * this routine is called through generic_file_aio_read(), the read/write fails
258 * with an error.
259 *
260 */
Aneesh Kumar K.Ve959b542011-02-28 17:04:04 +0530261static ssize_t
Al Virod8d3d942014-03-04 21:27:34 -0500262v9fs_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter, loff_t pos)
jvrao3e24ad22010-08-24 15:43:28 +0000263{
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530264 /*
265 * FIXME
266 * Now that we do caching with cache mode enabled, We need
267 * to support direct IO
268 */
Joe Perches5d385152011-11-28 10:40:46 -0800269 p9_debug(P9_DEBUG_VFS, "v9fs_direct_IO: v9fs_direct_IO (%s) off/no(%lld/%lu) EINVAL\n",
270 iocb->ki_filp->f_path.dentry->d_name.name,
Al Virod8d3d942014-03-04 21:27:34 -0500271 (long long)pos, iter->nr_segs);
jvrao3e24ad22010-08-24 15:43:28 +0000272
273 return -EINVAL;
274}
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530275
276static int v9fs_write_begin(struct file *filp, struct address_space *mapping,
277 loff_t pos, unsigned len, unsigned flags,
278 struct page **pagep, void **fsdata)
279{
280 int retval = 0;
281 struct page *page;
Aneesh Kumar K.V6b39f6d2011-02-28 17:04:03 +0530282 struct v9fs_inode *v9inode;
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530283 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
284 struct inode *inode = mapping->host;
285
Dominique Martinetfb89b452014-01-10 13:44:09 +0100286
287 p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
288
Aneesh Kumar K.V6b39f6d2011-02-28 17:04:03 +0530289 v9inode = V9FS_I(inode);
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530290start:
291 page = grab_cache_page_write_begin(mapping, index, flags);
292 if (!page) {
293 retval = -ENOMEM;
294 goto out;
295 }
Aneesh Kumar K.V6b39f6d2011-02-28 17:04:03 +0530296 BUG_ON(!v9inode->writeback_fid);
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530297 if (PageUptodate(page))
298 goto out;
299
300 if (len == PAGE_CACHE_SIZE)
301 goto out;
302
Aneesh Kumar K.V6b39f6d2011-02-28 17:04:03 +0530303 retval = v9fs_fid_readpage(v9inode->writeback_fid, page);
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530304 page_cache_release(page);
305 if (!retval)
306 goto start;
307out:
308 *pagep = page;
309 return retval;
310}
311
312static int v9fs_write_end(struct file *filp, struct address_space *mapping,
313 loff_t pos, unsigned len, unsigned copied,
314 struct page *page, void *fsdata)
315{
316 loff_t last_pos = pos + copied;
317 struct inode *inode = page->mapping->host;
318
Dominique Martinetfb89b452014-01-10 13:44:09 +0100319 p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
320
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530321 if (unlikely(copied < len)) {
322 /*
323 * zero out the rest of the area
324 */
325 unsigned from = pos & (PAGE_CACHE_SIZE - 1);
326
327 zero_user(page, from + copied, len - copied);
328 flush_dcache_page(page);
329 }
330
331 if (!PageUptodate(page))
332 SetPageUptodate(page);
333 /*
334 * No need to use i_size_read() here, the i_size
335 * cannot change under us because we hold the i_mutex.
336 */
337 if (last_pos > inode->i_size) {
338 inode_add_bytes(inode, last_pos - inode->i_size);
339 i_size_write(inode, last_pos);
340 }
341 set_page_dirty(page);
342 unlock_page(page);
343 page_cache_release(page);
344
345 return copied;
346}
347
348
Christoph Hellwigf5e54d62006-06-28 04:26:44 -0700349const struct address_space_operations v9fs_addr_operations = {
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530350 .readpage = v9fs_vfs_readpage,
351 .readpages = v9fs_vfs_readpages,
352 .set_page_dirty = __set_page_dirty_nobuffers,
353 .writepage = v9fs_vfs_writepage,
354 .write_begin = v9fs_write_begin,
355 .write_end = v9fs_write_end,
356 .releasepage = v9fs_release_page,
357 .invalidatepage = v9fs_invalidate_page,
358 .launder_page = v9fs_launder_page,
359 .direct_IO = v9fs_direct_IO,
Eric Van Hensbergen147b31c2006-01-18 17:43:02 -0800360};