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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/uio.h>
37#include <linux/bvec.h>
38#include <net/9p/9p.h>
39#include <net/9p/client.h>
40
41#include "v9fs.h"
42#include "v9fs_vfs.h"
43#include "cache.h"
44#include "fid.h"
45
46/**
47 * v9fs_fid_readpage - read an entire page in from 9P
48 *
49 * @fid: fid being read
50 * @page: structure to page
51 *
52 */
53static int v9fs_fid_readpage(struct p9_fid *fid, struct page *page)
54{
55 struct inode *inode = page->mapping->host;
56 struct bio_vec bvec = {.bv_page = page, .bv_len = PAGE_SIZE};
57 struct iov_iter to;
58 int retval, err;
59
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 iov_iter_bvec(&to, ITER_BVEC | READ, &bvec, 1, PAGE_SIZE);
69
70 retval = p9_client_read(fid, page_offset(page), &to, &err);
71 if (err) {
72 v9fs_uncache_page(inode, page);
73 retval = err;
74 goto done;
75 }
76
77 zero_user(page, retval, PAGE_SIZE - retval);
78 flush_dcache_page(page);
79 SetPageUptodate(page);
80
81 v9fs_readpage_to_fscache(inode, page);
82 retval = 0;
83
84done:
85 unlock_page(page);
86 return retval;
87}
88
89/**
90 * v9fs_vfs_readpage - read an entire page in from 9P
91 *
92 * @filp: file being read
93 * @page: structure to page
94 *
95 */
96
97static int v9fs_vfs_readpage(struct file *filp, struct page *page)
98{
99 return v9fs_fid_readpage(filp->private_data, page);
100}
101
102/**
103 * v9fs_vfs_readpages - read a set of pages from 9P
104 *
105 * @filp: file being read
106 * @mapping: the address space
107 * @pages: list of pages to read
108 * @nr_pages: count of pages to read
109 *
110 */
111
112static int v9fs_vfs_readpages(struct file *filp, struct address_space *mapping,
113 struct list_head *pages, unsigned nr_pages)
114{
115 int ret = 0;
116 struct inode *inode;
117
118 inode = mapping->host;
119 p9_debug(P9_DEBUG_VFS, "inode: %p file: %p\n", inode, filp);
120
121 ret = v9fs_readpages_from_fscache(inode, mapping, pages, &nr_pages);
122 if (ret == 0)
123 return ret;
124
125 ret = read_cache_pages(mapping, pages, (void *)v9fs_vfs_readpage, filp);
126 p9_debug(P9_DEBUG_VFS, " = %d\n", ret);
127 return ret;
128}
129
130/**
131 * v9fs_release_page - release the private state associated with a page
132 *
133 * Returns 1 if the page can be released, false otherwise.
134 */
135
136static int v9fs_release_page(struct page *page, gfp_t gfp)
137{
138 if (PagePrivate(page))
139 return 0;
140 return v9fs_fscache_release_page(page, gfp);
141}
142
143/**
144 * v9fs_invalidate_page - Invalidate a page completely or partially
145 *
146 * @page: structure to page
147 * @offset: offset in the page
148 */
149
150static void v9fs_invalidate_page(struct page *page, unsigned int offset,
151 unsigned int length)
152{
153 /*
154 * If called with zero offset, we should release
155 * the private state assocated with the page
156 */
157 if (offset == 0 && length == PAGE_SIZE)
158 v9fs_fscache_invalidate_page(page);
159}
160
161static int v9fs_vfs_writepage_locked(struct page *page)
162{
163 struct inode *inode = page->mapping->host;
164 struct v9fs_inode *v9inode = V9FS_I(inode);
165 loff_t size = i_size_read(inode);
166 struct iov_iter from;
167 struct bio_vec bvec;
168 int err, len;
169
170 if (page->index == size >> PAGE_SHIFT)
171 len = size & ~PAGE_MASK;
172 else
173 len = PAGE_SIZE;
174
175 bvec.bv_page = page;
176 bvec.bv_offset = 0;
177 bvec.bv_len = len;
178 iov_iter_bvec(&from, ITER_BVEC | WRITE, &bvec, 1, len);
179
180 /* We should have writeback_fid always set */
181 BUG_ON(!v9inode->writeback_fid);
182
183 set_page_writeback(page);
184
185 p9_client_write(v9inode->writeback_fid, page_offset(page), &from, &err);
186
187 end_page_writeback(page);
188 return err;
189}
190
191static int v9fs_vfs_writepage(struct page *page, struct writeback_control *wbc)
192{
193 int retval;
194
195 p9_debug(P9_DEBUG_VFS, "page %p\n", page);
196
197 retval = v9fs_vfs_writepage_locked(page);
198 if (retval < 0) {
199 if (retval == -EAGAIN) {
200 redirty_page_for_writepage(wbc, page);
201 retval = 0;
202 } else {
203 SetPageError(page);
204 mapping_set_error(page->mapping, retval);
205 }
206 } else
207 retval = 0;
208
209 unlock_page(page);
210 return retval;
211}
212
213/**
214 * v9fs_launder_page - Writeback a dirty page
215 * Returns 0 on success.
216 */
217
218static int v9fs_launder_page(struct page *page)
219{
220 int retval;
221 struct inode *inode = page->mapping->host;
222
223 v9fs_fscache_wait_on_page_write(inode, page);
224 if (clear_page_dirty_for_io(page)) {
225 retval = v9fs_vfs_writepage_locked(page);
226 if (retval)
227 return retval;
228 }
229 return 0;
230}
231
232/**
233 * v9fs_direct_IO - 9P address space operation for direct I/O
234 * @iocb: target I/O control block
235 *
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 */
247static ssize_t
248v9fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
249{
250 struct file *file = iocb->ki_filp;
251 loff_t pos = iocb->ki_pos;
252 ssize_t n;
253 int err = 0;
254 if (iov_iter_rw(iter) == WRITE) {
255 n = p9_client_write(file->private_data, pos, iter, &err);
256 if (n) {
257 struct inode *inode = file_inode(file);
258 loff_t i_size = i_size_read(inode);
259 if (pos + n > i_size)
260 inode_add_bytes(inode, pos + n - i_size);
261 }
262 } else {
263 n = p9_client_read(file->private_data, pos, iter, &err);
264 }
265 return n ? n : err;
266}
267
268static int v9fs_write_begin(struct file *filp, struct address_space *mapping,
269 loff_t pos, unsigned len, unsigned flags,
270 struct page **pagep, void **fsdata)
271{
272 int retval = 0;
273 struct page *page;
274 struct v9fs_inode *v9inode;
275 pgoff_t index = pos >> PAGE_SHIFT;
276 struct inode *inode = mapping->host;
277
278
279 p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
280
281 v9inode = V9FS_I(inode);
282start:
283 page = grab_cache_page_write_begin(mapping, index, flags);
284 if (!page) {
285 retval = -ENOMEM;
286 goto out;
287 }
288 BUG_ON(!v9inode->writeback_fid);
289 if (PageUptodate(page))
290 goto out;
291
292 if (len == PAGE_SIZE)
293 goto out;
294
295 retval = v9fs_fid_readpage(v9inode->writeback_fid, page);
296 put_page(page);
297 if (!retval)
298 goto start;
299out:
300 *pagep = page;
301 return retval;
302}
303
304static int v9fs_write_end(struct file *filp, struct address_space *mapping,
305 loff_t pos, unsigned len, unsigned copied,
306 struct page *page, void *fsdata)
307{
308 loff_t last_pos = pos + copied;
309 struct inode *inode = page->mapping->host;
310
311 p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
312
313 if (unlikely(copied < len && !PageUptodate(page))) {
314 copied = 0;
315 goto out;
316 }
317 /*
318 * No need to use i_size_read() here, the i_size
319 * cannot change under us because we hold the i_mutex.
320 */
321 if (last_pos > inode->i_size) {
322 inode_add_bytes(inode, last_pos - inode->i_size);
323 i_size_write(inode, last_pos);
324 }
325 set_page_dirty(page);
326out:
327 unlock_page(page);
328 put_page(page);
329
330 return copied;
331}
332
333
334const struct address_space_operations v9fs_addr_operations = {
335 .readpage = v9fs_vfs_readpage,
336 .readpages = v9fs_vfs_readpages,
337 .set_page_dirty = __set_page_dirty_nobuffers,
338 .writepage = v9fs_vfs_writepage,
339 .write_begin = v9fs_write_begin,
340 .write_end = v9fs_write_end,
341 .releasepage = v9fs_release_page,
342 .invalidatepage = v9fs_invalidate_page,
343 .launder_page = v9fs_launder_page,
344 .direct_IO = v9fs_direct_IO,
345};