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 | |
36 | struct 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 | |
48 | static 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 | |
68 | static 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(size: 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 | |
84 | static 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, 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 | */ |
147 | static 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 | 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 | |
205 | int 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 | |
239 | const 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 | |
247 | const 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 | |