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(inode: wreq->inode, want_writeable: true, INVALID_UID, any: 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, offset: subreq->start, from: &subreq->io_iter, err: &err);
60 if (len > 0)
61 __set_bit(NETFS_SREQ_MADE_PROGRESS, &subreq->flags);
62 netfs_write_subrequest_terminated(op: subreq, transferred_or_error: len ?: err);
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, offset: pos, to: &subreq->io_iter, err: &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_UNBUFFERED_READ &&
81 subreq->rreq->origin != NETFS_DIO_READ)
82 __set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags);
83 if (pos + total >= i_size_read(inode: rreq->inode))
84 __set_bit(NETFS_SREQ_HIT_EOF, &subreq->flags);
85 if (!err && total) {
86 subreq->transferred += total;
87 __set_bit(NETFS_SREQ_MADE_PROGRESS, &subreq->flags);
88 }
89
90 subreq->error = err;
91 netfs_read_subreq_terminated(subreq);
92}
93
94/**
95 * v9fs_init_request - Initialise a request
96 * @rreq: The read request
97 * @file: The file being read from
98 */
99static int v9fs_init_request(struct netfs_io_request *rreq, struct file *file)
100{
101 struct p9_fid *fid;
102 bool writing = (rreq->origin == NETFS_READ_FOR_WRITE ||
103 rreq->origin == NETFS_WRITETHROUGH ||
104 rreq->origin == NETFS_UNBUFFERED_WRITE ||
105 rreq->origin == NETFS_DIO_WRITE);
106
107 if (rreq->origin == NETFS_WRITEBACK)
108 return 0; /* We don't get the write handle until we find we
109 * have actually dirty data and not just
110 * copy-to-cache data.
111 */
112
113 if (file) {
114 fid = file->private_data;
115 if (!fid)
116 goto no_fid;
117 p9_fid_get(fid);
118 } else {
119 fid = v9fs_fid_find_inode(inode: rreq->inode, want_writeable: writing, INVALID_UID, any: true);
120 if (!fid)
121 goto no_fid;
122 }
123
124 rreq->wsize = fid->clnt->msize - P9_IOHDRSZ;
125 if (fid->iounit)
126 rreq->wsize = min(rreq->wsize, fid->iounit);
127
128 /* we might need to read from a fid that was opened write-only
129 * for read-modify-write of page cache, use the writeback fid
130 * for that */
131 WARN_ON(rreq->origin == NETFS_READ_FOR_WRITE && !(fid->mode & P9_ORDWR));
132 rreq->netfs_priv = fid;
133 return 0;
134
135no_fid:
136 WARN_ONCE(1, "folio expected an open fid inode->i_ino=%lx\n",
137 rreq->inode->i_ino);
138 return -EINVAL;
139}
140
141/**
142 * v9fs_free_request - Cleanup request initialized by v9fs_init_rreq
143 * @rreq: The I/O request to clean up
144 */
145static void v9fs_free_request(struct netfs_io_request *rreq)
146{
147 struct p9_fid *fid = rreq->netfs_priv;
148
149 p9_fid_put(fid);
150}
151
152const struct netfs_request_ops v9fs_req_ops = {
153 .init_request = v9fs_init_request,
154 .free_request = v9fs_free_request,
155 .issue_read = v9fs_issue_read,
156 .begin_writeback = v9fs_begin_writeback,
157 .issue_write = v9fs_issue_write,
158};
159
160const struct address_space_operations v9fs_addr_operations = {
161 .read_folio = netfs_read_folio,
162 .readahead = netfs_readahead,
163 .dirty_folio = netfs_dirty_folio,
164 .release_folio = netfs_release_folio,
165 .invalidate_folio = netfs_invalidate_folio,
166 .direct_IO = noop_direct_IO,
167 .writepages = netfs_writepages,
168 .migrate_folio = filemap_migrate_folio,
169};
170

source code of linux/fs/9p/vfs_addr.c