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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * This file contains vfs directory ops for the 9P2000 protocol.
4 *
5 * Copyright (C) 2004 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/sched.h>
16#include <linux/inet.h>
17#include <linux/slab.h>
18#include <linux/uio.h>
19#include <linux/fscache.h>
20#include <net/9p/9p.h>
21#include <net/9p/client.h>
22
23#include "v9fs.h"
24#include "v9fs_vfs.h"
25#include "fid.h"
26
27/**
28 * struct p9_rdir - readdir accounting
29 * @head: start offset of current dirread buffer
30 * @tail: end offset of current dirread buffer
31 * @buf: dirread buffer
32 *
33 * private structure for keeping track of readdir
34 * allocated on demand
35 */
36
37struct p9_rdir {
38 int head;
39 int tail;
40 uint8_t buf[];
41};
42
43/**
44 * dt_type - return file type
45 * @mistat: mistat structure
46 *
47 */
48
49static inline int dt_type(struct p9_wstat *mistat)
50{
51 unsigned long perm = mistat->mode;
52 int rettype = DT_REG;
53
54 if (perm & P9_DMDIR)
55 rettype = DT_DIR;
56 if (perm & P9_DMSYMLINK)
57 rettype = DT_LNK;
58
59 return rettype;
60}
61
62/**
63 * v9fs_alloc_rdir_buf - Allocate buffer used for read and readdir
64 * @filp: opened file structure
65 * @buflen: Length in bytes of buffer to allocate
66 *
67 */
68
69static struct p9_rdir *v9fs_alloc_rdir_buf(struct file *filp, int buflen)
70{
71 struct p9_fid *fid = filp->private_data;
72
73 if (!fid->rdir)
74 fid->rdir = kzalloc(sizeof(struct p9_rdir) + buflen, GFP_KERNEL);
75 return fid->rdir;
76}
77
78/**
79 * v9fs_dir_readdir - iterate through a directory
80 * @file: opened file structure
81 * @ctx: actor we feed the entries to
82 *
83 */
84
85static int v9fs_dir_readdir(struct file *file, struct dir_context *ctx)
86{
87 bool over;
88 struct p9_wstat st;
89 int err = 0;
90 struct p9_fid *fid;
91 int buflen;
92 struct p9_rdir *rdir;
93 struct kvec kvec;
94
95 p9_debug(P9_DEBUG_VFS, "name %pD\n", file);
96 fid = file->private_data;
97
98 buflen = fid->clnt->msize - P9_IOHDRSZ;
99
100 rdir = v9fs_alloc_rdir_buf(file, buflen);
101 if (!rdir)
102 return -ENOMEM;
103 kvec.iov_base = rdir->buf;
104 kvec.iov_len = buflen;
105
106 while (1) {
107 if (rdir->tail == rdir->head) {
108 struct iov_iter to;
109 int n;
110
111 iov_iter_kvec(&to, ITER_DEST, &kvec, 1, buflen);
112 n = p9_client_read(file->private_data, ctx->pos, &to,
113 &err);
114 if (err)
115 return err;
116 if (n == 0)
117 return 0;
118
119 rdir->head = 0;
120 rdir->tail = n;
121 }
122 while (rdir->head < rdir->tail) {
123 err = p9stat_read(fid->clnt, rdir->buf + rdir->head,
124 rdir->tail - rdir->head, &st);
125 if (err <= 0) {
126 p9_debug(P9_DEBUG_VFS, "returned %d\n", err);
127 return -EIO;
128 }
129
130 over = !dir_emit(ctx, st.name, strlen(st.name),
131 v9fs_qid2ino(&st.qid), dt_type(&st));
132 p9stat_free(&st);
133 if (over)
134 return 0;
135
136 rdir->head += err;
137 ctx->pos += err;
138 }
139 }
140}
141
142/**
143 * v9fs_dir_readdir_dotl - iterate through a directory
144 * @file: opened file structure
145 * @ctx: actor we feed the entries to
146 *
147 */
148static int v9fs_dir_readdir_dotl(struct file *file, struct dir_context *ctx)
149{
150 int err = 0;
151 struct p9_fid *fid;
152 int buflen;
153 struct p9_rdir *rdir;
154 struct p9_dirent curdirent;
155
156 p9_debug(P9_DEBUG_VFS, "name %pD\n", file);
157 fid = file->private_data;
158
159 buflen = fid->clnt->msize - P9_READDIRHDRSZ;
160
161 rdir = v9fs_alloc_rdir_buf(file, buflen);
162 if (!rdir)
163 return -ENOMEM;
164
165 while (1) {
166 if (rdir->tail == rdir->head) {
167 err = p9_client_readdir(fid, rdir->buf, buflen,
168 ctx->pos);
169 if (err <= 0)
170 return err;
171
172 rdir->head = 0;
173 rdir->tail = err;
174 }
175
176 while (rdir->head < rdir->tail) {
177
178 err = p9dirent_read(fid->clnt, rdir->buf + rdir->head,
179 rdir->tail - rdir->head,
180 &curdirent);
181 if (err < 0) {
182 p9_debug(P9_DEBUG_VFS, "returned %d\n", err);
183 return -EIO;
184 }
185
186 if (!dir_emit(ctx, curdirent.d_name,
187 strlen(curdirent.d_name),
188 v9fs_qid2ino(&curdirent.qid),
189 curdirent.d_type))
190 return 0;
191
192 ctx->pos = curdirent.d_off;
193 rdir->head += err;
194 }
195 }
196}
197
198
199/**
200 * v9fs_dir_release - close a directory
201 * @inode: inode of the directory
202 * @filp: file pointer to a directory
203 *
204 */
205
206int v9fs_dir_release(struct inode *inode, struct file *filp)
207{
208 struct v9fs_inode *v9inode = V9FS_I(inode);
209 struct p9_fid *fid;
210 __le32 version;
211 loff_t i_size;
212
213 fid = filp->private_data;
214 p9_debug(P9_DEBUG_VFS, "inode: %p filp: %p fid: %d\n",
215 inode, filp, fid ? fid->fid : -1);
216 if (fid) {
217 spin_lock(&inode->i_lock);
218 hlist_del(&fid->ilist);
219 spin_unlock(&inode->i_lock);
220 p9_fid_put(fid);
221 }
222
223 if ((filp->f_mode & FMODE_WRITE)) {
224 version = cpu_to_le32(v9inode->qid.version);
225 i_size = i_size_read(inode);
226 fscache_unuse_cookie(v9fs_inode_cookie(v9inode),
227 &version, &i_size);
228 } else {
229 fscache_unuse_cookie(v9fs_inode_cookie(v9inode), NULL, NULL);
230 }
231 return 0;
232}
233
234const struct file_operations v9fs_dir_operations = {
235 .read = generic_read_dir,
236 .llseek = generic_file_llseek,
237 .iterate_shared = v9fs_dir_readdir,
238 .open = v9fs_file_open,
239 .release = v9fs_dir_release,
240};
241
242const struct file_operations v9fs_dir_operations_dotl = {
243 .read = generic_read_dir,
244 .llseek = generic_file_llseek,
245 .iterate_shared = v9fs_dir_readdir_dotl,
246 .open = v9fs_file_open,
247 .release = v9fs_dir_release,
248 .fsync = v9fs_file_fsync_dotl,
249};