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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>
Christoph Hellwige2e40f22015-02-22 08:58:50 -080036#include <linux/uio.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{
Al Viroe1200fe62015-04-01 23:42:28 -040054 struct inode *inode = page->mapping->host;
55 struct bio_vec bvec = {.bv_page = page, .bv_len = PAGE_SIZE};
56 struct iov_iter to;
57 int retval, err;
Eric Van Hensbergen147b31c2006-01-18 17:43:02 -080058
Joe Perches5d385152011-11-28 10:40:46 -080059 p9_debug(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
Al Viroe1200fe62015-04-01 23:42:28 -040067 iov_iter_bvec(&to, ITER_BVEC | READ, &bvec, 1, PAGE_SIZE);
Eric Van Hensbergen147b31c2006-01-18 17:43:02 -080068
Al Viroe1200fe62015-04-01 23:42:28 -040069 retval = p9_client_read(fid, page_offset(page), &to, &err);
70 if (err) {
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -050071 v9fs_uncache_page(inode, page);
Al Viroe1200fe62015-04-01 23:42:28 -040072 retval = err;
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
Al Viroe1200fe62015-04-01 23:42:28 -040076 zero_user(page, retval, PAGE_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 unlock_page(page);
85 return retval;
86}
87
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -050088/**
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +053089 * v9fs_vfs_readpage - read an entire page in from 9P
90 *
91 * @filp: file being read
92 * @page: structure to page
93 *
94 */
95
96static int v9fs_vfs_readpage(struct file *filp, struct page *page)
97{
98 return v9fs_fid_readpage(filp->private_data, page);
99}
100
101/**
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500102 * v9fs_vfs_readpages - read a set of pages from 9P
103 *
104 * @filp: file being read
105 * @mapping: the address space
106 * @pages: list of pages to read
107 * @nr_pages: count of pages to read
108 *
109 */
110
111static int v9fs_vfs_readpages(struct file *filp, struct address_space *mapping,
112 struct list_head *pages, unsigned nr_pages)
113{
114 int ret = 0;
115 struct inode *inode;
116
117 inode = mapping->host;
Joe Perches5d385152011-11-28 10:40:46 -0800118 p9_debug(P9_DEBUG_VFS, "inode: %p file: %p\n", inode, filp);
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500119
120 ret = v9fs_readpages_from_fscache(inode, mapping, pages, &nr_pages);
121 if (ret == 0)
122 return ret;
123
124 ret = read_cache_pages(mapping, pages, (void *)v9fs_vfs_readpage, filp);
Joe Perches5d385152011-11-28 10:40:46 -0800125 p9_debug(P9_DEBUG_VFS, " = %d\n", ret);
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500126 return ret;
127}
128
129/**
130 * v9fs_release_page - release the private state associated with a page
131 *
132 * Returns 1 if the page can be released, false otherwise.
133 */
134
135static int v9fs_release_page(struct page *page, gfp_t gfp)
136{
137 if (PagePrivate(page))
138 return 0;
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500139 return v9fs_fscache_release_page(page, gfp);
140}
141
142/**
143 * v9fs_invalidate_page - Invalidate a page completely or partially
144 *
145 * @page: structure to page
146 * @offset: offset in the page
147 */
148
Lukas Czernerd47992f2013-05-21 23:17:23 -0400149static void v9fs_invalidate_page(struct page *page, unsigned int offset,
150 unsigned int length)
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500151{
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 */
Lukas Czernerd47992f2013-05-21 23:17:23 -0400156 if (offset == 0 && length == PAGE_CACHE_SIZE)
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500157 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{
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530162 struct inode *inode = page->mapping->host;
Al Viro371098c2015-04-01 21:54:42 -0400163 struct v9fs_inode *v9inode = V9FS_I(inode);
164 loff_t size = i_size_read(inode);
165 struct iov_iter from;
166 struct bio_vec bvec;
167 int err, len;
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530168
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530169 if (page->index == size >> PAGE_CACHE_SHIFT)
170 len = size & ~PAGE_CACHE_MASK;
171 else
172 len = PAGE_CACHE_SIZE;
173
Al Viro371098c2015-04-01 21:54:42 -0400174 bvec.bv_page = page;
175 bvec.bv_offset = 0;
176 bvec.bv_len = len;
177 iov_iter_bvec(&from, ITER_BVEC | WRITE, &bvec, 1, len);
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530178
Aneesh Kumar K.V6b39f6d2011-02-28 17:04:03 +0530179 /* We should have writeback_fid always set */
180 BUG_ON(!v9inode->writeback_fid);
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530181
Al Viro371098c2015-04-01 21:54:42 -0400182 set_page_writeback(page);
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530183
Al Viro371098c2015-04-01 21:54:42 -0400184 p9_client_write(v9inode->writeback_fid, page_offset(page), &from, &err);
185
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530186 end_page_writeback(page);
Al Viro371098c2015-04-01 21:54:42 -0400187 return err;
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530188}
189
190static int v9fs_vfs_writepage(struct page *page, struct writeback_control *wbc)
191{
192 int retval;
193
Dominique Martinetfb89b452014-01-10 13:44:09 +0100194 p9_debug(P9_DEBUG_VFS, "page %p\n", page);
195
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530196 retval = v9fs_vfs_writepage_locked(page);
197 if (retval < 0) {
198 if (retval == -EAGAIN) {
199 redirty_page_for_writepage(wbc, page);
200 retval = 0;
201 } else {
202 SetPageError(page);
203 mapping_set_error(page->mapping, retval);
204 }
205 } else
206 retval = 0;
207
208 unlock_page(page);
209 return retval;
210}
211
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500212/**
213 * v9fs_launder_page - Writeback a dirty page
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500214 * Returns 0 on success.
215 */
216
217static int v9fs_launder_page(struct page *page)
218{
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530219 int retval;
Aneesh Kumar K.V2efda792011-02-28 17:03:56 +0530220 struct inode *inode = page->mapping->host;
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530221
Aneesh Kumar K.V2efda792011-02-28 17:03:56 +0530222 v9fs_fscache_wait_on_page_write(inode, page);
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530223 if (clear_page_dirty_for_io(page)) {
224 retval = v9fs_vfs_writepage_locked(page);
225 if (retval)
226 return retval;
227 }
Abhishek Kulkarni60e78d22009-09-23 13:00:27 -0500228 return 0;
229}
230
jvrao3e24ad22010-08-24 15:43:28 +0000231/**
232 * v9fs_direct_IO - 9P address space operation for direct I/O
jvrao3e24ad22010-08-24 15:43:28 +0000233 * @iocb: target I/O control block
jvrao3e24ad22010-08-24 15:43:28 +0000234 * @pos: offset in file to begin the operation
jvrao3e24ad22010-08-24 15:43:28 +0000235 *
236 * The presence of v9fs_direct_IO() in the address space ops vector
237 * allowes open() O_DIRECT flags which would have failed otherwise.
238 *
239 * In the non-cached mode, we shunt off direct read and write requests before
240 * the VFS gets them, so this method should never be called.
241 *
242 * Direct IO is not 'yet' supported in the cached mode. Hence when
243 * this routine is called through generic_file_aio_read(), the read/write fails
244 * with an error.
245 *
246 */
Aneesh Kumar K.Ve959b542011-02-28 17:04:04 +0530247static ssize_t
Omar Sandoval22c61862015-03-16 04:33:53 -0700248v9fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t pos)
jvrao3e24ad22010-08-24 15:43:28 +0000249{
Al Viro9565a542015-04-01 22:32:23 -0400250 struct file *file = iocb->ki_filp;
Al Viro42b1ab92015-04-01 23:49:24 -0400251 ssize_t n;
252 int err = 0;
Omar Sandoval6f673762015-03-16 04:33:52 -0700253 if (iov_iter_rw(iter) == WRITE) {
Al Viro42b1ab92015-04-01 23:49:24 -0400254 n = p9_client_write(file->private_data, pos, iter, &err);
255 if (n) {
Al Viro9565a542015-04-01 22:32:23 -0400256 struct inode *inode = file_inode(file);
257 loff_t i_size = i_size_read(inode);
Al Viro42b1ab92015-04-01 23:49:24 -0400258 if (pos + n > i_size)
259 inode_add_bytes(inode, pos + n - i_size);
Al Viro9565a542015-04-01 22:32:23 -0400260 }
Al Viro42b1ab92015-04-01 23:49:24 -0400261 } else {
262 n = p9_client_read(file->private_data, pos, iter, &err);
Al Viro9565a542015-04-01 22:32:23 -0400263 }
Al Viro42b1ab92015-04-01 23:49:24 -0400264 return n ? n : err;
jvrao3e24ad22010-08-24 15:43:28 +0000265}
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530266
267static int v9fs_write_begin(struct file *filp, struct address_space *mapping,
268 loff_t pos, unsigned len, unsigned flags,
269 struct page **pagep, void **fsdata)
270{
271 int retval = 0;
272 struct page *page;
Aneesh Kumar K.V6b39f6d2011-02-28 17:04:03 +0530273 struct v9fs_inode *v9inode;
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530274 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
275 struct inode *inode = mapping->host;
276
Dominique Martinetfb89b452014-01-10 13:44:09 +0100277
278 p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
279
Aneesh Kumar K.V6b39f6d2011-02-28 17:04:03 +0530280 v9inode = V9FS_I(inode);
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530281start:
282 page = grab_cache_page_write_begin(mapping, index, flags);
283 if (!page) {
284 retval = -ENOMEM;
285 goto out;
286 }
Aneesh Kumar K.V6b39f6d2011-02-28 17:04:03 +0530287 BUG_ON(!v9inode->writeback_fid);
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530288 if (PageUptodate(page))
289 goto out;
290
291 if (len == PAGE_CACHE_SIZE)
292 goto out;
293
Aneesh Kumar K.V6b39f6d2011-02-28 17:04:03 +0530294 retval = v9fs_fid_readpage(v9inode->writeback_fid, page);
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530295 page_cache_release(page);
296 if (!retval)
297 goto start;
298out:
299 *pagep = page;
300 return retval;
301}
302
303static int v9fs_write_end(struct file *filp, struct address_space *mapping,
304 loff_t pos, unsigned len, unsigned copied,
305 struct page *page, void *fsdata)
306{
307 loff_t last_pos = pos + copied;
308 struct inode *inode = page->mapping->host;
309
Dominique Martinetfb89b452014-01-10 13:44:09 +0100310 p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
311
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530312 if (unlikely(copied < len)) {
313 /*
314 * zero out the rest of the area
315 */
316 unsigned from = pos & (PAGE_CACHE_SIZE - 1);
317
318 zero_user(page, from + copied, len - copied);
319 flush_dcache_page(page);
320 }
321
322 if (!PageUptodate(page))
323 SetPageUptodate(page);
324 /*
325 * No need to use i_size_read() here, the i_size
326 * cannot change under us because we hold the i_mutex.
327 */
328 if (last_pos > inode->i_size) {
329 inode_add_bytes(inode, last_pos - inode->i_size);
330 i_size_write(inode, last_pos);
331 }
332 set_page_dirty(page);
333 unlock_page(page);
334 page_cache_release(page);
335
336 return copied;
337}
338
339
Christoph Hellwigf5e54d62006-06-28 04:26:44 -0700340const struct address_space_operations v9fs_addr_operations = {
Aneesh Kumar K.V7263ceb2011-02-28 17:03:58 +0530341 .readpage = v9fs_vfs_readpage,
342 .readpages = v9fs_vfs_readpages,
343 .set_page_dirty = __set_page_dirty_nobuffers,
344 .writepage = v9fs_vfs_writepage,
345 .write_begin = v9fs_write_begin,
346 .write_end = v9fs_write_end,
347 .releasepage = v9fs_release_page,
348 .invalidatepage = v9fs_invalidate_page,
349 .launder_page = v9fs_launder_page,
350 .direct_IO = v9fs_direct_IO,
Eric Van Hensbergen147b31c2006-01-18 17:43:02 -0800351};