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>
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/aio.h>
37 #include <net/9p/9p.h>
38 #include <net/9p/client.h>
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)
59 inode = page->mapping->host;
60 p9_debug(P9_DEBUG_VFS, "\n");
62 BUG_ON(!PageLocked(page));
64 retval = v9fs_readpage_from_fscache(inode, page);
69 offset = page_offset(page);
71 retval = v9fs_fid_readn(fid, buffer, NULL, PAGE_CACHE_SIZE, offset);
73 v9fs_uncache_page(inode, page);
77 memset(buffer + retval, 0, PAGE_CACHE_SIZE - retval);
78 flush_dcache_page(page);
79 SetPageUptodate(page);
81 v9fs_readpage_to_fscache(inode, page);
91 * v9fs_vfs_readpage - read an entire page in from 9P
93 * @filp: file being read
94 * @page: structure to page
98 static int v9fs_vfs_readpage(struct file *filp, struct page *page)
100 return v9fs_fid_readpage(filp->private_data, page);
104 * v9fs_vfs_readpages - read a set of pages from 9P
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
113 static int v9fs_vfs_readpages(struct file *filp, struct address_space *mapping,
114 struct list_head *pages, unsigned nr_pages)
119 inode = mapping->host;
120 p9_debug(P9_DEBUG_VFS, "inode: %p file: %p\n", inode, filp);
122 ret = v9fs_readpages_from_fscache(inode, mapping, pages, &nr_pages);
126 ret = read_cache_pages(mapping, pages, (void *)v9fs_vfs_readpage, filp);
127 p9_debug(P9_DEBUG_VFS, " = %d\n", ret);
132 * v9fs_release_page - release the private state associated with a page
134 * Returns 1 if the page can be released, false otherwise.
137 static int v9fs_release_page(struct page *page, gfp_t gfp)
139 if (PagePrivate(page))
141 return v9fs_fscache_release_page(page, gfp);
145 * v9fs_invalidate_page - Invalidate a page completely or partially
147 * @page: structure to page
148 * @offset: offset in the page
151 static void v9fs_invalidate_page(struct page *page, unsigned int offset,
155 * If called with zero offset, we should release
156 * the private state assocated with the page
158 if (offset == 0 && length == PAGE_CACHE_SIZE)
159 v9fs_fscache_invalidate_page(page);
162 static int v9fs_vfs_writepage_locked(struct page *page)
168 struct v9fs_inode *v9inode;
169 struct inode *inode = page->mapping->host;
171 v9inode = V9FS_I(inode);
172 size = i_size_read(inode);
173 if (page->index == size >> PAGE_CACHE_SHIFT)
174 len = size & ~PAGE_CACHE_MASK;
176 len = PAGE_CACHE_SIZE;
178 set_page_writeback(page);
181 offset = page_offset(page);
185 /* We should have writeback_fid always set */
186 BUG_ON(!v9inode->writeback_fid);
188 retval = v9fs_file_write_internal(inode,
189 v9inode->writeback_fid,
190 (__force const char __user *)buffer,
197 end_page_writeback(page);
201 static int v9fs_vfs_writepage(struct page *page, struct writeback_control *wbc)
205 retval = v9fs_vfs_writepage_locked(page);
207 if (retval == -EAGAIN) {
208 redirty_page_for_writepage(wbc, page);
212 mapping_set_error(page->mapping, retval);
222 * v9fs_launder_page - Writeback a dirty page
223 * Returns 0 on success.
226 static int v9fs_launder_page(struct page *page)
229 struct inode *inode = page->mapping->host;
231 v9fs_fscache_wait_on_page_write(inode, page);
232 if (clear_page_dirty_for_io(page)) {
233 retval = v9fs_vfs_writepage_locked(page);
241 * v9fs_direct_IO - 9P address space operation for direct I/O
242 * @rw: direction (read or write)
243 * @iocb: target I/O control block
244 * @iter: array of vectors that define I/O buffer
245 * @pos: offset in file to begin the operation
247 * The presence of v9fs_direct_IO() in the address space ops vector
248 * allowes open() O_DIRECT flags which would have failed otherwise.
250 * In the non-cached mode, we shunt off direct read and write requests before
251 * the VFS gets them, so this method should never be called.
253 * Direct IO is not 'yet' supported in the cached mode. Hence when
254 * this routine is called through generic_file_aio_read(), the read/write fails
259 v9fs_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter, loff_t pos)
263 * Now that we do caching with cache mode enabled, We need
264 * to support direct IO
266 p9_debug(P9_DEBUG_VFS, "v9fs_direct_IO: v9fs_direct_IO (%s) off/no(%lld/%lu) EINVAL\n",
267 iocb->ki_filp->f_path.dentry->d_name.name,
268 (long long)pos, iter->nr_segs);
273 static int v9fs_write_begin(struct file *filp, struct address_space *mapping,
274 loff_t pos, unsigned len, unsigned flags,
275 struct page **pagep, void **fsdata)
279 struct v9fs_inode *v9inode;
280 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
281 struct inode *inode = mapping->host;
283 v9inode = V9FS_I(inode);
285 page = grab_cache_page_write_begin(mapping, index, flags);
290 BUG_ON(!v9inode->writeback_fid);
291 if (PageUptodate(page))
294 if (len == PAGE_CACHE_SIZE)
297 retval = v9fs_fid_readpage(v9inode->writeback_fid, page);
298 page_cache_release(page);
306 static int v9fs_write_end(struct file *filp, struct address_space *mapping,
307 loff_t pos, unsigned len, unsigned copied,
308 struct page *page, void *fsdata)
310 loff_t last_pos = pos + copied;
311 struct inode *inode = page->mapping->host;
313 if (unlikely(copied < len)) {
315 * zero out the rest of the area
317 unsigned from = pos & (PAGE_CACHE_SIZE - 1);
319 zero_user(page, from + copied, len - copied);
320 flush_dcache_page(page);
323 if (!PageUptodate(page))
324 SetPageUptodate(page);
326 * No need to use i_size_read() here, the i_size
327 * cannot change under us because we hold the i_mutex.
329 if (last_pos > inode->i_size) {
330 inode_add_bytes(inode, last_pos - inode->i_size);
331 i_size_write(inode, last_pos);
333 set_page_dirty(page);
335 page_cache_release(page);
341 const struct address_space_operations v9fs_addr_operations = {
342 .readpage = v9fs_vfs_readpage,
343 .readpages = v9fs_vfs_readpages,
344 .set_page_dirty = __set_page_dirty_nobuffers,
345 .writepage = v9fs_vfs_writepage,
346 .write_begin = v9fs_write_begin,
347 .write_end = v9fs_write_end,
348 .releasepage = v9fs_release_page,
349 .invalidatepage = v9fs_invalidate_page,
350 .launder_page = v9fs_launder_page,
351 .direct_IO = v9fs_direct_IO,