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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * This file contians vfs address (mmap) ops for 9P2000.
4 *
5 * Copyright (C) 2005 by Eric Van Hensbergen <ericvh@gmail.com>
6 * Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
7 */
8
9#include <linux/module.h>
10#include <linux/errno.h>
11#include <linux/fs.h>
12#include <linux/file.h>
13#include <linux/stat.h>
14#include <linux/string.h>
15#include <linux/pagemap.h>
16#include <linux/sched.h>
17#include <linux/swap.h>
18#include <linux/uio.h>
19#include <linux/netfs.h>
20#include <net/9p/9p.h>
21#include <net/9p/client.h>
22#include <trace/events/netfs.h>
23
24#include "v9fs.h"
25#include "v9fs_vfs.h"
26#include "cache.h"
27#include "fid.h"
28
29/*
30 * Writeback calls this when it finds a folio that needs uploading. This isn't
31 * called if writeback only has copy-to-cache to deal with.
32 */
33static void v9fs_begin_writeback(struct netfs_io_request *wreq)
34{
35 struct p9_fid *fid;
36
37 fid = v9fs_fid_find_inode(wreq->inode, true, INVALID_UID, true);
38 if (!fid) {
39 WARN_ONCE(1, "folio expected an open fid inode->i_ino=%lx\n",
40 wreq->inode->i_ino);
41 return;
42 }
43
44 wreq->wsize = fid->clnt->msize - P9_IOHDRSZ;
45 if (fid->iounit)
46 wreq->wsize = min(wreq->wsize, fid->iounit);
47 wreq->netfs_priv = fid;
48 wreq->io_streams[0].avail = true;
49}
50
51/*
52 * Issue a subrequest to write to the server.
53 */
54static void v9fs_issue_write(struct netfs_io_subrequest *subreq)
55{
56 struct p9_fid *fid = subreq->rreq->netfs_priv;
57 int err, len;
58
59 len = p9_client_write(fid, subreq->start, &subreq->io_iter, &err);
60 if (len > 0)
61 __set_bit(NETFS_SREQ_MADE_PROGRESS, &subreq->flags);
62 netfs_write_subrequest_terminated(subreq, len ?: err, false);
63}
64
65/**
66 * v9fs_issue_read - Issue a read from 9P
67 * @subreq: The read to make
68 */
69static void v9fs_issue_read(struct netfs_io_subrequest *subreq)
70{
71 struct netfs_io_request *rreq = subreq->rreq;
72 struct p9_fid *fid = rreq->netfs_priv;
73 unsigned long long pos = subreq->start + subreq->transferred;
74 int total, err;
75
76 total = p9_client_read(fid, pos, &subreq->io_iter, &err);
77
78 /* if we just extended the file size, any portion not in
79 * cache won't be on server and is zeroes */
80 if (subreq->rreq->origin != NETFS_DIO_READ)
81 __set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags);
82 if (pos + total >= i_size_read(rreq->inode))
83 __set_bit(NETFS_SREQ_HIT_EOF, &subreq->flags);
84
85 if (!err) {
86 subreq->transferred += total;
87 __set_bit(NETFS_SREQ_MADE_PROGRESS, &subreq->flags);
88 }
89
90 netfs_read_subreq_terminated(subreq, err, false);
91}
92
93/**
94 * v9fs_init_request - Initialise a request
95 * @rreq: The read request
96 * @file: The file being read from
97 */
98static int v9fs_init_request(struct netfs_io_request *rreq, struct file *file)
99{
100 struct p9_fid *fid;
101 bool writing = (rreq->origin == NETFS_READ_FOR_WRITE ||
102 rreq->origin == NETFS_WRITETHROUGH ||
103 rreq->origin == NETFS_UNBUFFERED_WRITE ||
104 rreq->origin == NETFS_DIO_WRITE);
105
106 if (rreq->origin == NETFS_WRITEBACK)
107 return 0; /* We don't get the write handle until we find we
108 * have actually dirty data and not just
109 * copy-to-cache data.
110 */
111
112 if (file) {
113 fid = file->private_data;
114 if (!fid)
115 goto no_fid;
116 p9_fid_get(fid);
117 } else {
118 fid = v9fs_fid_find_inode(rreq->inode, writing, INVALID_UID, true);
119 if (!fid)
120 goto no_fid;
121 }
122
123 rreq->wsize = fid->clnt->msize - P9_IOHDRSZ;
124 if (fid->iounit)
125 rreq->wsize = min(rreq->wsize, fid->iounit);
126
127 /* we might need to read from a fid that was opened write-only
128 * for read-modify-write of page cache, use the writeback fid
129 * for that */
130 WARN_ON(rreq->origin == NETFS_READ_FOR_WRITE && !(fid->mode & P9_ORDWR));
131 rreq->netfs_priv = fid;
132 return 0;
133
134no_fid:
135 WARN_ONCE(1, "folio expected an open fid inode->i_ino=%lx\n",
136 rreq->inode->i_ino);
137 return -EINVAL;
138}
139
140/**
141 * v9fs_free_request - Cleanup request initialized by v9fs_init_rreq
142 * @rreq: The I/O request to clean up
143 */
144static void v9fs_free_request(struct netfs_io_request *rreq)
145{
146 struct p9_fid *fid = rreq->netfs_priv;
147
148 p9_fid_put(fid);
149}
150
151const struct netfs_request_ops v9fs_req_ops = {
152 .init_request = v9fs_init_request,
153 .free_request = v9fs_free_request,
154 .issue_read = v9fs_issue_read,
155 .begin_writeback = v9fs_begin_writeback,
156 .issue_write = v9fs_issue_write,
157};
158
159const struct address_space_operations v9fs_addr_operations = {
160 .read_folio = netfs_read_folio,
161 .readahead = netfs_readahead,
162 .dirty_folio = netfs_dirty_folio,
163 .release_folio = netfs_release_folio,
164 .invalidate_folio = netfs_invalidate_folio,
165 .direct_IO = noop_direct_IO,
166 .writepages = netfs_writepages,
167};
1/*
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
10 * it under the terms of the GNU General Public License version 2
11 * as published by the Free Software Foundation.
12 *
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>
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>
39
40#include "v9fs.h"
41#include "v9fs_vfs.h"
42#include "cache.h"
43#include "fid.h"
44
45/**
46 * v9fs_fid_readpage - read an entire page in from 9P
47 *
48 * @fid: fid being read
49 * @page: structure to page
50 *
51 */
52static int v9fs_fid_readpage(struct p9_fid *fid, struct page *page)
53{
54 int retval;
55 loff_t offset;
56 char *buffer;
57 struct inode *inode;
58
59 inode = page->mapping->host;
60 p9_debug(P9_DEBUG_VFS, "\n");
61
62 BUG_ON(!PageLocked(page));
63
64 retval = v9fs_readpage_from_fscache(inode, page);
65 if (retval == 0)
66 return retval;
67
68 buffer = kmap(page);
69 offset = page_offset(page);
70
71 retval = v9fs_fid_readn(fid, buffer, NULL, PAGE_CACHE_SIZE, offset);
72 if (retval < 0) {
73 v9fs_uncache_page(inode, page);
74 goto done;
75 }
76
77 memset(buffer + retval, 0, PAGE_CACHE_SIZE - retval);
78 flush_dcache_page(page);
79 SetPageUptodate(page);
80
81 v9fs_readpage_to_fscache(inode, page);
82 retval = 0;
83
84done:
85 kunmap(page);
86 unlock_page(page);
87 return retval;
88}
89
90/**
91 * 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/**
104 * 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;
120 p9_debug(P9_DEBUG_VFS, "inode: %p file: %p\n", inode, filp);
121
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);
127 p9_debug(P9_DEBUG_VFS, " = %d\n", ret);
128 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;
141 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
151static void v9fs_invalidate_page(struct page *page, unsigned int offset,
152 unsigned int length)
153{
154 /*
155 * If called with zero offset, we should release
156 * the private state assocated with the page
157 */
158 if (offset == 0 && length == PAGE_CACHE_SIZE)
159 v9fs_fscache_invalidate_page(page);
160}
161
162static 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;
168 struct v9fs_inode *v9inode;
169 struct inode *inode = page->mapping->host;
170
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;
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());
185 /* We should have writeback_fid always set */
186 BUG_ON(!v9inode->writeback_fid);
187
188 retval = v9fs_file_write_internal(inode,
189 v9inode->writeback_fid,
190 (__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
205 p9_debug(P9_DEBUG_VFS, "page %p\n", page);
206
207 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
223/**
224 * v9fs_launder_page - Writeback a dirty page
225 * Returns 0 on success.
226 */
227
228static int v9fs_launder_page(struct page *page)
229{
230 int retval;
231 struct inode *inode = page->mapping->host;
232
233 v9fs_fscache_wait_on_page_write(inode, page);
234 if (clear_page_dirty_for_io(page)) {
235 retval = v9fs_vfs_writepage_locked(page);
236 if (retval)
237 return retval;
238 }
239 return 0;
240}
241
242/**
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 */
261static ssize_t
262v9fs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
263 loff_t pos, unsigned long nr_segs)
264{
265 /*
266 * FIXME
267 * Now that we do caching with cache mode enabled, We need
268 * to support direct IO
269 */
270 p9_debug(P9_DEBUG_VFS, "v9fs_direct_IO: v9fs_direct_IO (%s) off/no(%lld/%lu) EINVAL\n",
271 iocb->ki_filp->f_path.dentry->d_name.name,
272 (long long)pos, nr_segs);
273
274 return -EINVAL;
275}
276
277static int v9fs_write_begin(struct file *filp, struct address_space *mapping,
278 loff_t pos, unsigned len, unsigned flags,
279 struct page **pagep, void **fsdata)
280{
281 int retval = 0;
282 struct page *page;
283 struct v9fs_inode *v9inode;
284 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
285 struct inode *inode = mapping->host;
286
287
288 p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
289
290 v9inode = V9FS_I(inode);
291start:
292 page = grab_cache_page_write_begin(mapping, index, flags);
293 if (!page) {
294 retval = -ENOMEM;
295 goto out;
296 }
297 BUG_ON(!v9inode->writeback_fid);
298 if (PageUptodate(page))
299 goto out;
300
301 if (len == PAGE_CACHE_SIZE)
302 goto out;
303
304 retval = v9fs_fid_readpage(v9inode->writeback_fid, page);
305 page_cache_release(page);
306 if (!retval)
307 goto start;
308out:
309 *pagep = page;
310 return retval;
311}
312
313static int v9fs_write_end(struct file *filp, struct address_space *mapping,
314 loff_t pos, unsigned len, unsigned copied,
315 struct page *page, void *fsdata)
316{
317 loff_t last_pos = pos + copied;
318 struct inode *inode = page->mapping->host;
319
320 p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
321
322 if (unlikely(copied < len)) {
323 /*
324 * zero out the rest of the area
325 */
326 unsigned from = pos & (PAGE_CACHE_SIZE - 1);
327
328 zero_user(page, from + copied, len - copied);
329 flush_dcache_page(page);
330 }
331
332 if (!PageUptodate(page))
333 SetPageUptodate(page);
334 /*
335 * No need to use i_size_read() here, the i_size
336 * cannot change under us because we hold the i_mutex.
337 */
338 if (last_pos > inode->i_size) {
339 inode_add_bytes(inode, last_pos - inode->i_size);
340 i_size_write(inode, last_pos);
341 }
342 set_page_dirty(page);
343 unlock_page(page);
344 page_cache_release(page);
345
346 return copied;
347}
348
349
350const struct address_space_operations v9fs_addr_operations = {
351 .readpage = v9fs_vfs_readpage,
352 .readpages = v9fs_vfs_readpages,
353 .set_page_dirty = __set_page_dirty_nobuffers,
354 .writepage = v9fs_vfs_writepage,
355 .write_begin = v9fs_write_begin,
356 .write_end = v9fs_write_end,
357 .releasepage = v9fs_release_page,
358 .invalidatepage = v9fs_invalidate_page,
359 .launder_page = v9fs_launder_page,
360 .direct_IO = v9fs_direct_IO,
361};