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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};