Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6
[linux/fpc-iii.git] / fs / 9p / vfs_addr.c
blobe9e04376c52ce8ef4673d041281c1db1e2c4ac99
1 /*
2 * linux/fs/9p/vfs_addr.c
4 * This file contians vfs address (mmap) ops for 9P2000.
6 * Copyright (C) 2005 by Eric Van Hensbergen <ericvh@gmail.com>
7 * Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2
11 * as published by the Free Software Foundation.
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.
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
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>
32 #include <linux/inet.h>
33 #include <linux/pagemap.h>
34 #include <linux/idr.h>
35 #include <linux/sched.h>
36 #include <linux/uio.h>
37 #include <net/9p/9p.h>
38 #include <net/9p/client.h>
40 #include "v9fs.h"
41 #include "v9fs_vfs.h"
42 #include "cache.h"
43 #include "fid.h"
45 /**
46 * v9fs_fid_readpage - read an entire page in from 9P
48 * @fid: fid being read
49 * @page: structure to page
52 static int v9fs_fid_readpage(struct p9_fid *fid, struct page *page)
54 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;
59 p9_debug(P9_DEBUG_VFS, "\n");
61 BUG_ON(!PageLocked(page));
63 retval = v9fs_readpage_from_fscache(inode, page);
64 if (retval == 0)
65 return retval;
67 iov_iter_bvec(&to, ITER_BVEC | READ, &bvec, 1, PAGE_SIZE);
69 retval = p9_client_read(fid, page_offset(page), &to, &err);
70 if (err) {
71 v9fs_uncache_page(inode, page);
72 retval = err;
73 goto done;
76 zero_user(page, retval, PAGE_SIZE - retval);
77 flush_dcache_page(page);
78 SetPageUptodate(page);
80 v9fs_readpage_to_fscache(inode, page);
81 retval = 0;
83 done:
84 unlock_page(page);
85 return retval;
88 /**
89 * v9fs_vfs_readpage - read an entire page in from 9P
91 * @filp: file being read
92 * @page: structure to page
96 static int v9fs_vfs_readpage(struct file *filp, struct page *page)
98 return v9fs_fid_readpage(filp->private_data, page);
102 * v9fs_vfs_readpages - read a set of pages from 9P
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
111 static int v9fs_vfs_readpages(struct file *filp, struct address_space *mapping,
112 struct list_head *pages, unsigned nr_pages)
114 int ret = 0;
115 struct inode *inode;
117 inode = mapping->host;
118 p9_debug(P9_DEBUG_VFS, "inode: %p file: %p\n", inode, filp);
120 ret = v9fs_readpages_from_fscache(inode, mapping, pages, &nr_pages);
121 if (ret == 0)
122 return ret;
124 ret = read_cache_pages(mapping, pages, (void *)v9fs_vfs_readpage, filp);
125 p9_debug(P9_DEBUG_VFS, " = %d\n", ret);
126 return ret;
130 * v9fs_release_page - release the private state associated with a page
132 * Returns 1 if the page can be released, false otherwise.
135 static int v9fs_release_page(struct page *page, gfp_t gfp)
137 if (PagePrivate(page))
138 return 0;
139 return v9fs_fscache_release_page(page, gfp);
143 * v9fs_invalidate_page - Invalidate a page completely or partially
145 * @page: structure to page
146 * @offset: offset in the page
149 static void v9fs_invalidate_page(struct page *page, unsigned int offset,
150 unsigned int length)
153 * If called with zero offset, we should release
154 * the private state assocated with the page
156 if (offset == 0 && length == PAGE_CACHE_SIZE)
157 v9fs_fscache_invalidate_page(page);
160 static int v9fs_vfs_writepage_locked(struct page *page)
162 struct inode *inode = page->mapping->host;
163 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;
169 if (page->index == size >> PAGE_CACHE_SHIFT)
170 len = size & ~PAGE_CACHE_MASK;
171 else
172 len = PAGE_CACHE_SIZE;
174 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);
179 /* We should have writeback_fid always set */
180 BUG_ON(!v9inode->writeback_fid);
182 set_page_writeback(page);
184 p9_client_write(v9inode->writeback_fid, page_offset(page), &from, &err);
186 end_page_writeback(page);
187 return err;
190 static int v9fs_vfs_writepage(struct page *page, struct writeback_control *wbc)
192 int retval;
194 p9_debug(P9_DEBUG_VFS, "page %p\n", page);
196 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);
205 } else
206 retval = 0;
208 unlock_page(page);
209 return retval;
213 * v9fs_launder_page - Writeback a dirty page
214 * Returns 0 on success.
217 static int v9fs_launder_page(struct page *page)
219 int retval;
220 struct inode *inode = page->mapping->host;
222 v9fs_fscache_wait_on_page_write(inode, page);
223 if (clear_page_dirty_for_io(page)) {
224 retval = v9fs_vfs_writepage_locked(page);
225 if (retval)
226 return retval;
228 return 0;
232 * v9fs_direct_IO - 9P address space operation for direct I/O
233 * @iocb: target I/O control block
234 * @pos: offset in file to begin the operation
236 * The presence of v9fs_direct_IO() in the address space ops vector
237 * allowes open() O_DIRECT flags which would have failed otherwise.
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.
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.
247 static ssize_t
248 v9fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t pos)
250 struct file *file = iocb->ki_filp;
251 ssize_t n;
252 int err = 0;
253 if (iov_iter_rw(iter) == WRITE) {
254 n = p9_client_write(file->private_data, pos, iter, &err);
255 if (n) {
256 struct inode *inode = file_inode(file);
257 loff_t i_size = i_size_read(inode);
258 if (pos + n > i_size)
259 inode_add_bytes(inode, pos + n - i_size);
261 } else {
262 n = p9_client_read(file->private_data, pos, iter, &err);
264 return n ? n : err;
267 static 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)
271 int retval = 0;
272 struct page *page;
273 struct v9fs_inode *v9inode;
274 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
275 struct inode *inode = mapping->host;
278 p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
280 v9inode = V9FS_I(inode);
281 start:
282 page = grab_cache_page_write_begin(mapping, index, flags);
283 if (!page) {
284 retval = -ENOMEM;
285 goto out;
287 BUG_ON(!v9inode->writeback_fid);
288 if (PageUptodate(page))
289 goto out;
291 if (len == PAGE_CACHE_SIZE)
292 goto out;
294 retval = v9fs_fid_readpage(v9inode->writeback_fid, page);
295 page_cache_release(page);
296 if (!retval)
297 goto start;
298 out:
299 *pagep = page;
300 return retval;
303 static 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)
307 loff_t last_pos = pos + copied;
308 struct inode *inode = page->mapping->host;
310 p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
312 if (unlikely(copied < len)) {
314 * zero out the rest of the area
316 unsigned from = pos & (PAGE_CACHE_SIZE - 1);
318 zero_user(page, from + copied, len - copied);
319 flush_dcache_page(page);
322 if (!PageUptodate(page))
323 SetPageUptodate(page);
325 * No need to use i_size_read() here, the i_size
326 * cannot change under us because we hold the i_mutex.
328 if (last_pos > inode->i_size) {
329 inode_add_bytes(inode, last_pos - inode->i_size);
330 i_size_write(inode, last_pos);
332 set_page_dirty(page);
333 unlock_page(page);
334 page_cache_release(page);
336 return copied;
340 const struct address_space_operations v9fs_addr_operations = {
341 .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,