1 // SPDX-License-Identifier: GPL-2.0-only
3 * linux/fs/9p/vfs_addr.c
5 * This file contians vfs address (mmap) ops for 9P2000.
7 * Copyright (C) 2005 by Eric Van Hensbergen <ericvh@gmail.com>
8 * Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
11 #include <linux/module.h>
12 #include <linux/errno.h>
14 #include <linux/file.h>
15 #include <linux/stat.h>
16 #include <linux/string.h>
17 #include <linux/inet.h>
18 #include <linux/pagemap.h>
19 #include <linux/idr.h>
20 #include <linux/sched.h>
21 #include <linux/uio.h>
22 #include <linux/bvec.h>
23 #include <net/9p/9p.h>
24 #include <net/9p/client.h>
32 * v9fs_fid_readpage - read an entire page in from 9P
34 * @fid: fid being read
35 * @page: structure to page
38 static int v9fs_fid_readpage(struct p9_fid *fid, struct page *page)
40 struct inode *inode = page->mapping->host;
41 struct bio_vec bvec = {.bv_page = page, .bv_len = PAGE_SIZE};
45 p9_debug(P9_DEBUG_VFS, "\n");
47 BUG_ON(!PageLocked(page));
49 retval = v9fs_readpage_from_fscache(inode, page);
53 iov_iter_bvec(&to, READ, &bvec, 1, PAGE_SIZE);
55 retval = p9_client_read(fid, page_offset(page), &to, &err);
57 v9fs_uncache_page(inode, page);
62 zero_user(page, retval, PAGE_SIZE - retval);
63 flush_dcache_page(page);
64 SetPageUptodate(page);
66 v9fs_readpage_to_fscache(inode, page);
75 * v9fs_vfs_readpage - read an entire page in from 9P
77 * @filp: file being read
78 * @page: structure to page
82 static int v9fs_vfs_readpage(struct file *filp, struct page *page)
84 return v9fs_fid_readpage(filp->private_data, page);
88 * v9fs_vfs_readpages - read a set of pages from 9P
90 * @filp: file being read
91 * @mapping: the address space
92 * @pages: list of pages to read
93 * @nr_pages: count of pages to read
97 static int v9fs_vfs_readpages(struct file *filp, struct address_space *mapping,
98 struct list_head *pages, unsigned nr_pages)
103 inode = mapping->host;
104 p9_debug(P9_DEBUG_VFS, "inode: %p file: %p\n", inode, filp);
106 ret = v9fs_readpages_from_fscache(inode, mapping, pages, &nr_pages);
110 ret = read_cache_pages(mapping, pages, (void *)v9fs_vfs_readpage, filp);
111 p9_debug(P9_DEBUG_VFS, " = %d\n", ret);
116 * v9fs_release_page - release the private state associated with a page
118 * Returns 1 if the page can be released, false otherwise.
121 static int v9fs_release_page(struct page *page, gfp_t gfp)
123 if (PagePrivate(page))
125 return v9fs_fscache_release_page(page, gfp);
129 * v9fs_invalidate_page - Invalidate a page completely or partially
131 * @page: structure to page
132 * @offset: offset in the page
135 static void v9fs_invalidate_page(struct page *page, unsigned int offset,
139 * If called with zero offset, we should release
140 * the private state assocated with the page
142 if (offset == 0 && length == PAGE_SIZE)
143 v9fs_fscache_invalidate_page(page);
146 static int v9fs_vfs_writepage_locked(struct page *page)
148 struct inode *inode = page->mapping->host;
149 struct v9fs_inode *v9inode = V9FS_I(inode);
150 loff_t size = i_size_read(inode);
151 struct iov_iter from;
155 if (page->index == size >> PAGE_SHIFT)
156 len = size & ~PAGE_MASK;
163 iov_iter_bvec(&from, WRITE, &bvec, 1, len);
165 /* We should have writeback_fid always set */
166 BUG_ON(!v9inode->writeback_fid);
168 set_page_writeback(page);
170 p9_client_write(v9inode->writeback_fid, page_offset(page), &from, &err);
172 end_page_writeback(page);
176 static int v9fs_vfs_writepage(struct page *page, struct writeback_control *wbc)
180 p9_debug(P9_DEBUG_VFS, "page %p\n", page);
182 retval = v9fs_vfs_writepage_locked(page);
184 if (retval == -EAGAIN) {
185 redirty_page_for_writepage(wbc, page);
189 mapping_set_error(page->mapping, retval);
199 * v9fs_launder_page - Writeback a dirty page
200 * Returns 0 on success.
203 static int v9fs_launder_page(struct page *page)
206 struct inode *inode = page->mapping->host;
208 v9fs_fscache_wait_on_page_write(inode, page);
209 if (clear_page_dirty_for_io(page)) {
210 retval = v9fs_vfs_writepage_locked(page);
218 * v9fs_direct_IO - 9P address space operation for direct I/O
219 * @iocb: target I/O control block
221 * The presence of v9fs_direct_IO() in the address space ops vector
222 * allowes open() O_DIRECT flags which would have failed otherwise.
224 * In the non-cached mode, we shunt off direct read and write requests before
225 * the VFS gets them, so this method should never be called.
227 * Direct IO is not 'yet' supported in the cached mode. Hence when
228 * this routine is called through generic_file_aio_read(), the read/write fails
233 v9fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
235 struct file *file = iocb->ki_filp;
236 loff_t pos = iocb->ki_pos;
239 if (iov_iter_rw(iter) == WRITE) {
240 n = p9_client_write(file->private_data, pos, iter, &err);
242 struct inode *inode = file_inode(file);
243 loff_t i_size = i_size_read(inode);
244 if (pos + n > i_size)
245 inode_add_bytes(inode, pos + n - i_size);
248 n = p9_client_read(file->private_data, pos, iter, &err);
253 static int v9fs_write_begin(struct file *filp, struct address_space *mapping,
254 loff_t pos, unsigned len, unsigned flags,
255 struct page **pagep, void **fsdata)
259 struct v9fs_inode *v9inode;
260 pgoff_t index = pos >> PAGE_SHIFT;
261 struct inode *inode = mapping->host;
264 p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
266 v9inode = V9FS_I(inode);
268 page = grab_cache_page_write_begin(mapping, index, flags);
273 BUG_ON(!v9inode->writeback_fid);
274 if (PageUptodate(page))
277 if (len == PAGE_SIZE)
280 retval = v9fs_fid_readpage(v9inode->writeback_fid, page);
289 static int v9fs_write_end(struct file *filp, struct address_space *mapping,
290 loff_t pos, unsigned len, unsigned copied,
291 struct page *page, void *fsdata)
293 loff_t last_pos = pos + copied;
294 struct inode *inode = page->mapping->host;
296 p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
298 if (!PageUptodate(page)) {
299 if (unlikely(copied < len)) {
302 } else if (len == PAGE_SIZE) {
303 SetPageUptodate(page);
307 * No need to use i_size_read() here, the i_size
308 * cannot change under us because we hold the i_mutex.
310 if (last_pos > inode->i_size) {
311 inode_add_bytes(inode, last_pos - inode->i_size);
312 i_size_write(inode, last_pos);
314 set_page_dirty(page);
323 const struct address_space_operations v9fs_addr_operations = {
324 .readpage = v9fs_vfs_readpage,
325 .readpages = v9fs_vfs_readpages,
326 .set_page_dirty = __set_page_dirty_nobuffers,
327 .writepage = v9fs_vfs_writepage,
328 .write_begin = v9fs_write_begin,
329 .write_end = v9fs_write_end,
330 .releasepage = v9fs_release_page,
331 .invalidatepage = v9fs_invalidate_page,
332 .launder_page = v9fs_launder_page,
333 .direct_IO = v9fs_direct_IO,