1 /*
2 * 9p backend
3 *
4 * Copyright IBM, Corp. 2011
5 *
6 * Authors:
7 * Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
8 *
9 * This work is licensed under the terms of the GNU GPL, version 2. See
10 * the COPYING file in the top-level directory.
11 *
12 */
13
14 /*
15 * Not so fast! You might want to read the 9p developer docs first:
16 * https://wiki.qemu.org/Documentation/9p
17 */
18
19 #include "qemu/osdep.h"
20 #include "fsdev/qemu-fsdev.h"
21 #include "qemu/thread.h"
22 #include "qemu/main-loop.h"
23 #include "coth.h"
24
v9fs_co_st_gen(V9fsPDU * pdu,V9fsPath * path,mode_t st_mode,V9fsStatDotl * v9stat)25 int coroutine_fn v9fs_co_st_gen(V9fsPDU *pdu, V9fsPath *path, mode_t st_mode,
26 V9fsStatDotl *v9stat)
27 {
28 int err = 0;
29 V9fsState *s = pdu->s;
30
31 if (v9fs_request_cancelled(pdu)) {
32 return -EINTR;
33 }
34 if (s->ctx.exops.get_st_gen) {
35 v9fs_path_read_lock(s);
36 v9fs_co_run_in_worker(
37 {
38 err = s->ctx.exops.get_st_gen(&s->ctx, path, st_mode,
39 &v9stat->st_gen);
40 if (err < 0) {
41 err = -errno;
42 }
43 });
44 v9fs_path_unlock(s);
45 }
46 return err;
47 }
48
v9fs_co_lstat(V9fsPDU * pdu,V9fsPath * path,struct stat * stbuf)49 int coroutine_fn v9fs_co_lstat(V9fsPDU *pdu, V9fsPath *path, struct stat *stbuf)
50 {
51 int err;
52 V9fsState *s = pdu->s;
53
54 if (v9fs_request_cancelled(pdu)) {
55 return -EINTR;
56 }
57 v9fs_path_read_lock(s);
58 v9fs_co_run_in_worker(
59 {
60 err = s->ops->lstat(&s->ctx, path, stbuf);
61 if (err < 0) {
62 err = -errno;
63 }
64 });
65 v9fs_path_unlock(s);
66 return err;
67 }
68
v9fs_co_fstat(V9fsPDU * pdu,V9fsFidState * fidp,struct stat * stbuf)69 int coroutine_fn v9fs_co_fstat(V9fsPDU *pdu, V9fsFidState *fidp,
70 struct stat *stbuf)
71 {
72 int err;
73 V9fsState *s = pdu->s;
74
75 if (v9fs_request_cancelled(pdu)) {
76 return -EINTR;
77 }
78 v9fs_co_run_in_worker(
79 {
80 err = s->ops->fstat(&s->ctx, fidp->fid_type, &fidp->fs, stbuf);
81 if (err < 0) {
82 err = -errno;
83 }
84 });
85 /*
86 * Some FS driver (local:mapped-file) can't support fetching attributes
87 * using file descriptor. Use Path name in that case.
88 */
89 if (err == -EOPNOTSUPP) {
90 err = v9fs_co_lstat(pdu, &fidp->path, stbuf);
91 if (err == -ENOENT) {
92 /*
93 * fstat on an unlinked file. Work with partial results
94 * returned from s->ops->fstat
95 */
96 err = 0;
97 }
98 }
99 return err;
100 }
101
v9fs_co_open(V9fsPDU * pdu,V9fsFidState * fidp,int flags)102 int coroutine_fn v9fs_co_open(V9fsPDU *pdu, V9fsFidState *fidp, int flags)
103 {
104 int err;
105 V9fsState *s = pdu->s;
106
107 if (v9fs_request_cancelled(pdu)) {
108 return -EINTR;
109 }
110 v9fs_path_read_lock(s);
111 v9fs_co_run_in_worker(
112 {
113 err = s->ops->open(&s->ctx, &fidp->path, flags, &fidp->fs);
114 if (err == -1) {
115 err = -errno;
116 } else {
117 err = 0;
118 }
119 });
120 v9fs_path_unlock(s);
121 if (!err) {
122 total_open_fd++;
123 if (total_open_fd > open_fd_hw) {
124 v9fs_reclaim_fd(pdu);
125 }
126 }
127 return err;
128 }
129
v9fs_co_open2(V9fsPDU * pdu,V9fsFidState * fidp,V9fsString * name,gid_t gid,int flags,int mode,struct stat * stbuf)130 int coroutine_fn v9fs_co_open2(V9fsPDU *pdu, V9fsFidState *fidp,
131 V9fsString *name, gid_t gid, int flags, int mode,
132 struct stat *stbuf)
133 {
134 int err;
135 FsCred cred;
136 V9fsPath path;
137 V9fsState *s = pdu->s;
138
139 if (v9fs_request_cancelled(pdu)) {
140 return -EINTR;
141 }
142 cred_init(&cred);
143 cred.fc_mode = mode & 07777;
144 cred.fc_uid = fidp->uid;
145 cred.fc_gid = gid;
146 /*
147 * Hold the directory fid lock so that directory path name
148 * don't change. Take the write lock to be sure this fid
149 * cannot be used by another operation.
150 */
151 v9fs_path_write_lock(s);
152 v9fs_co_run_in_worker(
153 {
154 err = s->ops->open2(&s->ctx, &fidp->path,
155 name->data, flags, &cred, &fidp->fs);
156 if (err < 0) {
157 err = -errno;
158 } else {
159 v9fs_path_init(&path);
160 err = v9fs_name_to_path(s, &fidp->path, name->data, &path);
161 if (!err) {
162 err = s->ops->lstat(&s->ctx, &path, stbuf);
163 if (err < 0) {
164 err = -errno;
165 s->ops->close(&s->ctx, &fidp->fs);
166 } else {
167 v9fs_path_copy(&fidp->path, &path);
168 }
169 } else {
170 s->ops->close(&s->ctx, &fidp->fs);
171 }
172 v9fs_path_free(&path);
173 }
174 });
175 v9fs_path_unlock(s);
176 if (!err) {
177 total_open_fd++;
178 if (total_open_fd > open_fd_hw) {
179 v9fs_reclaim_fd(pdu);
180 }
181 }
182 return err;
183 }
184
v9fs_co_close(V9fsPDU * pdu,V9fsFidOpenState * fs)185 int coroutine_fn v9fs_co_close(V9fsPDU *pdu, V9fsFidOpenState *fs)
186 {
187 int err;
188 V9fsState *s = pdu->s;
189
190 if (v9fs_request_cancelled(pdu)) {
191 return -EINTR;
192 }
193 v9fs_co_run_in_worker(
194 {
195 err = s->ops->close(&s->ctx, fs);
196 if (err < 0) {
197 err = -errno;
198 }
199 });
200 if (!err) {
201 total_open_fd--;
202 }
203 return err;
204 }
205
v9fs_co_fsync(V9fsPDU * pdu,V9fsFidState * fidp,int datasync)206 int coroutine_fn v9fs_co_fsync(V9fsPDU *pdu, V9fsFidState *fidp, int datasync)
207 {
208 int err;
209 V9fsState *s = pdu->s;
210
211 if (v9fs_request_cancelled(pdu)) {
212 return -EINTR;
213 }
214 v9fs_co_run_in_worker(
215 {
216 err = s->ops->fsync(&s->ctx, fidp->fid_type, &fidp->fs, datasync);
217 if (err < 0) {
218 err = -errno;
219 }
220 });
221 return err;
222 }
223
v9fs_co_link(V9fsPDU * pdu,V9fsFidState * oldfid,V9fsFidState * newdirfid,V9fsString * name)224 int coroutine_fn v9fs_co_link(V9fsPDU *pdu, V9fsFidState *oldfid,
225 V9fsFidState *newdirfid, V9fsString *name)
226 {
227 int err;
228 V9fsState *s = pdu->s;
229
230 if (v9fs_request_cancelled(pdu)) {
231 return -EINTR;
232 }
233 v9fs_path_read_lock(s);
234 v9fs_co_run_in_worker(
235 {
236 err = s->ops->link(&s->ctx, &oldfid->path,
237 &newdirfid->path, name->data);
238 if (err < 0) {
239 err = -errno;
240 }
241 });
242 v9fs_path_unlock(s);
243 return err;
244 }
245
v9fs_co_pwritev(V9fsPDU * pdu,V9fsFidState * fidp,struct iovec * iov,int iovcnt,int64_t offset)246 int coroutine_fn v9fs_co_pwritev(V9fsPDU *pdu, V9fsFidState *fidp,
247 struct iovec *iov, int iovcnt, int64_t offset)
248 {
249 int err;
250 V9fsState *s = pdu->s;
251
252 if (v9fs_request_cancelled(pdu)) {
253 return -EINTR;
254 }
255 fsdev_co_throttle_request(s->ctx.fst, THROTTLE_WRITE, iov, iovcnt);
256 v9fs_co_run_in_worker(
257 {
258 err = s->ops->pwritev(&s->ctx, &fidp->fs, iov, iovcnt, offset);
259 if (err < 0) {
260 err = -errno;
261 }
262 });
263 return err;
264 }
265
v9fs_co_preadv(V9fsPDU * pdu,V9fsFidState * fidp,struct iovec * iov,int iovcnt,int64_t offset)266 int coroutine_fn v9fs_co_preadv(V9fsPDU *pdu, V9fsFidState *fidp,
267 struct iovec *iov, int iovcnt, int64_t offset)
268 {
269 int err;
270 V9fsState *s = pdu->s;
271
272 if (v9fs_request_cancelled(pdu)) {
273 return -EINTR;
274 }
275 fsdev_co_throttle_request(s->ctx.fst, THROTTLE_READ, iov, iovcnt);
276 v9fs_co_run_in_worker(
277 {
278 err = s->ops->preadv(&s->ctx, &fidp->fs, iov, iovcnt, offset);
279 if (err < 0) {
280 err = -errno;
281 }
282 });
283 return err;
284 }
285