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/slab.h>
17#include <linux/uio.h>
18#include <linux/fscache.h>
19#include <net/9p/9p.h>
20#include <net/9p/client.h>
21
22#include "v9fs.h"
23#include "v9fs_vfs.h"
24#include "fid.h"
25
26/**
27 * struct p9_rdir - readdir accounting
28 * @head: start offset of current dirread buffer
29 * @tail: end offset of current dirread buffer
30 * @buf: dirread buffer
31 *
32 * private structure for keeping track of readdir
33 * allocated on demand
34 */
35
36struct p9_rdir {
37 int head;
38 int tail;
39 uint8_t buf[];
40};
41
42/**
43 * dt_type - return file type
44 * @mistat: mistat structure
45 *
46 */
47
48static inline int dt_type(struct p9_wstat *mistat)
49{
50 unsigned long perm = mistat->mode;
51 int rettype = DT_REG;
52
53 if (perm & P9_DMDIR)
54 rettype = DT_DIR;
55 if (perm & P9_DMSYMLINK)
56 rettype = DT_LNK;
57
58 return rettype;
59}
60
61/**
62 * v9fs_alloc_rdir_buf - Allocate buffer used for read and readdir
63 * @filp: opened file structure
64 * @buflen: Length in bytes of buffer to allocate
65 *
66 */
67
68static struct p9_rdir *v9fs_alloc_rdir_buf(struct file *filp, int buflen)
69{
70 struct p9_fid *fid = filp->private_data;
71
72 if (!fid->rdir)
73 fid->rdir = kzalloc(sizeof(struct p9_rdir) + buflen, GFP_KERNEL);
74 return fid->rdir;
75}
76
77/**
78 * v9fs_dir_readdir - iterate through a directory
79 * @file: opened file structure
80 * @ctx: actor we feed the entries to
81 *
82 */
83
84static int v9fs_dir_readdir(struct file *file, struct dir_context *ctx)
85{
86 bool over;
87 struct p9_wstat st;
88 int err = 0;
89 struct p9_fid *fid;
90 int buflen;
91 struct p9_rdir *rdir;
92 struct kvec kvec;
93
94 p9_debug(P9_DEBUG_VFS, "name %pD\n", file);
95 fid = file->private_data;
96
97 buflen = fid->clnt->msize - P9_IOHDRSZ;
98
99 rdir = v9fs_alloc_rdir_buf(filp: file, buflen);
100 if (!rdir)
101 return -ENOMEM;
102 kvec.iov_base = rdir->buf;
103 kvec.iov_len = buflen;
104
105 while (1) {
106 if (rdir->tail == rdir->head) {
107 struct iov_iter to;
108 int n;
109
110 iov_iter_kvec(i: &to, ITER_DEST, kvec: &kvec, nr_segs: 1, count: buflen);
111 n = p9_client_read(fid: file->private_data, offset: ctx->pos, to: &to,
112 err: &err);
113 if (err)
114 return err;
115 if (n == 0)
116 return 0;
117
118 rdir->head = 0;
119 rdir->tail = n;
120 }
121 while (rdir->head < rdir->tail) {
122 err = p9stat_read(clnt: fid->clnt, buf: rdir->buf + rdir->head,
123 len: rdir->tail - rdir->head, st: &st);
124 if (err <= 0) {
125 p9_debug(P9_DEBUG_VFS, "returned %d\n", err);
126 return -EIO;
127 }
128
129 over = !dir_emit(ctx, name: st.name, namelen: strlen(st.name),
130 QID2INO(&st.qid), type: dt_type(mistat: &st));
131 p9stat_free(stbuf: &st);
132 if (over)
133 return 0;
134
135 rdir->head += err;
136 ctx->pos += err;
137 }
138 }
139}
140
141/**
142 * v9fs_dir_readdir_dotl - iterate through a directory
143 * @file: opened file structure
144 * @ctx: actor we feed the entries to
145 *
146 */
147static int v9fs_dir_readdir_dotl(struct file *file, struct dir_context *ctx)
148{
149 int err = 0;
150 struct p9_fid *fid;
151 int buflen;
152 struct p9_rdir *rdir;
153 struct p9_dirent curdirent;
154
155 p9_debug(P9_DEBUG_VFS, "name %pD\n", file);
156 fid = file->private_data;
157
158 buflen = fid->clnt->msize - P9_READDIRHDRSZ;
159
160 rdir = v9fs_alloc_rdir_buf(filp: file, buflen);
161 if (!rdir)
162 return -ENOMEM;
163
164 while (1) {
165 if (rdir->tail == rdir->head) {
166 err = p9_client_readdir(fid, data: rdir->buf, count: buflen,
167 offset: ctx->pos);
168 if (err <= 0)
169 return err;
170
171 rdir->head = 0;
172 rdir->tail = err;
173 }
174
175 while (rdir->head < rdir->tail) {
176
177 err = p9dirent_read(clnt: fid->clnt, buf: rdir->buf + rdir->head,
178 len: rdir->tail - rdir->head,
179 dirent: &curdirent);
180 if (err < 0) {
181 p9_debug(P9_DEBUG_VFS, "returned %d\n", err);
182 return -EIO;
183 }
184
185 if (!dir_emit(ctx, name: curdirent.d_name,
186 namelen: strlen(curdirent.d_name),
187 QID2INO(&curdirent.qid),
188 type: curdirent.d_type))
189 return 0;
190
191 ctx->pos = curdirent.d_off;
192 rdir->head += err;
193 }
194 }
195}
196
197
198/**
199 * v9fs_dir_release - close a directory or a file
200 * @inode: inode of the directory or file
201 * @filp: file pointer to a directory or file
202 *
203 */
204
205int v9fs_dir_release(struct inode *inode, struct file *filp)
206{
207 struct v9fs_inode *v9inode = V9FS_I(inode);
208 struct p9_fid *fid;
209 __le32 version;
210 loff_t i_size;
211 int retval = 0, put_err;
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
217 if (fid) {
218 if ((S_ISREG(inode->i_mode)) && (filp->f_mode & FMODE_WRITE))
219 retval = filemap_fdatawrite(inode->i_mapping);
220
221 spin_lock(lock: &inode->i_lock);
222 hlist_del(n: &fid->ilist);
223 spin_unlock(lock: &inode->i_lock);
224 put_err = p9_fid_put(fid);
225 retval = retval < 0 ? retval : put_err;
226 }
227
228 if ((filp->f_mode & FMODE_WRITE)) {
229 version = cpu_to_le32(v9inode->qid.version);
230 i_size = i_size_read(inode);
231 fscache_unuse_cookie(cookie: v9fs_inode_cookie(v9inode),
232 aux_data: &version, object_size: &i_size);
233 } else {
234 fscache_unuse_cookie(cookie: v9fs_inode_cookie(v9inode), NULL, NULL);
235 }
236 return retval;
237}
238
239const struct file_operations v9fs_dir_operations = {
240 .read = generic_read_dir,
241 .llseek = generic_file_llseek,
242 .iterate_shared = v9fs_dir_readdir,
243 .open = v9fs_file_open,
244 .release = v9fs_dir_release,
245};
246
247const struct file_operations v9fs_dir_operations_dotl = {
248 .read = generic_read_dir,
249 .llseek = generic_file_llseek,
250 .iterate_shared = v9fs_dir_readdir_dotl,
251 .open = v9fs_file_open,
252 .release = v9fs_dir_release,
253 .fsync = v9fs_file_fsync_dotl,
254};
255