1 /* $NetBSD: mfs_vfsops.c,v 1.116 2022/03/19 13:53:33 hannken Exp $ */
2
3 /*
4 * Copyright (c) 1989, 1990, 1993, 1994
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 *
31 * @(#)mfs_vfsops.c 8.11 (Berkeley) 6/19/95
32 */
33
34 #include <sys/cdefs.h>
35 __KERNEL_RCSID(0, "$NetBSD: mfs_vfsops.c,v 1.116 2022/03/19 13:53:33 hannken Exp $");
36
37 #if defined(_KERNEL_OPT)
38 #include "opt_compat_netbsd.h"
39 #endif
40
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #include <sys/sysctl.h>
44 #include <sys/time.h>
45 #include <sys/kernel.h>
46 #include <sys/proc.h>
47 #include <sys/buf.h>
48 #include <sys/bufq.h>
49 #include <sys/mount.h>
50 #include <sys/signalvar.h>
51 #include <sys/vnode.h>
52 #include <sys/kmem.h>
53 #include <sys/module.h>
54
55 #include <miscfs/genfs/genfs.h>
56 #include <miscfs/specfs/specdev.h>
57
58 #include <ufs/ufs/quota.h>
59 #include <ufs/ufs/inode.h>
60 #include <ufs/ufs/ufsmount.h>
61 #include <ufs/ufs/ufs_extern.h>
62
63 #include <ufs/ffs/fs.h>
64 #include <ufs/ffs/ffs_extern.h>
65
66 #include <ufs/mfs/mfsnode.h>
67 #include <ufs/mfs/mfs_extern.h>
68
69 MODULE(MODULE_CLASS_VFS, mfs, "ffs");
70
71 kmutex_t mfs_lock; /* global lock */
72
73 /* used for building internal dev_t, minor == 0 reserved for miniroot */
74 static devminor_t mfs_minor = 1;
75 static int mfs_initcnt;
76
77 extern int (**mfs_vnodeop_p)(void *);
78
79 /*
80 * mfs vfs operations.
81 */
82
83 extern const struct vnodeopv_desc mfs_vnodeop_opv_desc;
84
85 const struct vnodeopv_desc * const mfs_vnodeopv_descs[] = {
86 &mfs_vnodeop_opv_desc,
87 NULL,
88 };
89
90 struct vfsops mfs_vfsops = {
91 .vfs_name = MOUNT_MFS,
92 .vfs_min_mount_data = sizeof (struct mfs_args),
93 .vfs_mount = mfs_mount,
94 .vfs_start = mfs_start,
95 .vfs_unmount = ffs_unmount,
96 .vfs_root = ufs_root,
97 .vfs_quotactl = ufs_quotactl,
98 .vfs_statvfs = mfs_statvfs,
99 .vfs_sync = ffs_sync,
100 .vfs_vget = ufs_vget,
101 .vfs_loadvnode = ffs_loadvnode,
102 .vfs_newvnode = ffs_newvnode,
103 .vfs_fhtovp = ffs_fhtovp,
104 .vfs_vptofh = ffs_vptofh,
105 .vfs_init = mfs_init,
106 .vfs_reinit = mfs_reinit,
107 .vfs_done = mfs_done,
108 .vfs_snapshot = (void *)eopnotsupp,
109 .vfs_extattrctl = vfs_stdextattrctl,
110 .vfs_suspendctl = genfs_suspendctl,
111 .vfs_renamelock_enter = genfs_renamelock_enter,
112 .vfs_renamelock_exit = genfs_renamelock_exit,
113 .vfs_fsync = (void *)eopnotsupp,
114 .vfs_opv_descs = mfs_vnodeopv_descs
115 };
116
117 SYSCTL_SETUP(mfs_sysctl_setup, "mfs sysctl")
118 {
119
120 sysctl_createv(clog, 0, NULL, NULL,
121 CTLFLAG_PERMANENT|CTLFLAG_ALIAS,
122 CTLTYPE_NODE, "mfs",
123 SYSCTL_DESCR("Memory based file system"),
124 NULL, 1, NULL, 0,
125 CTL_VFS, 3, CTL_EOL);
126 /*
127 * XXX the "1" and the "3" above could be dynamic, thereby
128 * eliminating one more instance of the "number to vfs"
129 * mapping problem, but they are in order as taken from
130 * sys/mount.h
131 */
132 }
133
134 static int
mfs_modcmd(modcmd_t cmd,void * arg)135 mfs_modcmd(modcmd_t cmd, void *arg)
136 {
137 int error;
138
139 switch (cmd) {
140 case MODULE_CMD_INIT:
141 error = vfs_attach(&mfs_vfsops);
142 if (error != 0)
143 break;
144 break;
145 case MODULE_CMD_FINI:
146 error = vfs_detach(&mfs_vfsops);
147 if (error != 0)
148 break;
149 break;
150 default:
151 error = ENOTTY;
152 break;
153 }
154
155 return (error);
156 }
157
158 /*
159 * Memory based filesystem initialization.
160 */
161 void
mfs_init(void)162 mfs_init(void)
163 {
164
165 if (mfs_initcnt++ == 0) {
166 mutex_init(&mfs_lock, MUTEX_DEFAULT, IPL_NONE);
167 ffs_init();
168 }
169 }
170
171 void
mfs_reinit(void)172 mfs_reinit(void)
173 {
174
175 ffs_reinit();
176 }
177
178 void
mfs_done(void)179 mfs_done(void)
180 {
181
182 if (--mfs_initcnt == 0) {
183 ffs_done();
184 mutex_destroy(&mfs_lock);
185 }
186 }
187
188 /*
189 * Called by main() when mfs is going to be mounted as root.
190 */
191
192 int
mfs_mountroot(void)193 mfs_mountroot(void)
194 {
195 struct fs *fs;
196 struct mount *mp;
197 struct lwp *l = curlwp; /* XXX */
198 struct ufsmount *ump;
199 struct mfsnode *mfsp;
200 int error = 0;
201
202 if ((error = vfs_rootmountalloc(MOUNT_MFS, "mfs_root", &mp))) {
203 vrele(rootvp);
204 return (error);
205 }
206
207 mfsp = kmem_alloc(sizeof(*mfsp), KM_SLEEP);
208 rootvp->v_data = mfsp;
209 rootvp->v_op = mfs_vnodeop_p;
210 rootvp->v_tag = VT_MFS;
211 mfsp->mfs_baseoff = mfs_rootbase;
212 mfsp->mfs_size = mfs_rootsize;
213 mfsp->mfs_vnode = rootvp;
214 mfsp->mfs_proc = NULL; /* indicate kernel space */
215 mfsp->mfs_shutdown = 0;
216 cv_init(&mfsp->mfs_cv, "mfs");
217 mfsp->mfs_refcnt = 1;
218 bufq_alloc(&mfsp->mfs_buflist, "fcfs", 0);
219 if ((error = ffs_mountfs(rootvp, mp, l)) != 0) {
220 vfs_unbusy(mp);
221 bufq_free(mfsp->mfs_buflist);
222 vfs_rele(mp);
223 kmem_free(mfsp, sizeof(*mfsp));
224 return (error);
225 }
226 mountlist_append(mp);
227 mp->mnt_vnodecovered = NULLVP;
228 ump = VFSTOUFS(mp);
229 fs = ump->um_fs;
230 (void) copystr(mp->mnt_stat.f_mntonname, fs->fs_fsmnt, MNAMELEN - 1, 0);
231 (void)ffs_statvfs(mp, &mp->mnt_stat);
232 vfs_unbusy(mp);
233 return (0);
234 }
235
236 /*
237 * VFS Operations.
238 *
239 * mount system call
240 */
241 /* ARGSUSED */
242 int
mfs_mount(struct mount * mp,const char * path,void * data,size_t * data_len)243 mfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len)
244 {
245 struct lwp *l = curlwp;
246 struct vnode *devvp;
247 struct mfs_args *args = data;
248 struct ufsmount *ump;
249 struct fs *fs;
250 struct mfsnode *mfsp;
251 struct proc *p;
252 devminor_t minor;
253 int flags, error = 0;
254
255 if (args == NULL)
256 return EINVAL;
257 if (*data_len < sizeof *args)
258 return EINVAL;
259
260 p = l->l_proc;
261 if (mp->mnt_flag & MNT_GETARGS) {
262 struct vnode *vp;
263
264 ump = VFSTOUFS(mp);
265 if (ump == NULL)
266 return EIO;
267
268 vp = ump->um_devvp;
269 if (vp == NULL)
270 return EIO;
271
272 mfsp = VTOMFS(vp);
273 if (mfsp == NULL)
274 return EIO;
275
276 args->fspec = NULL;
277 args->base = mfsp->mfs_baseoff;
278 args->size = mfsp->mfs_size;
279 *data_len = sizeof *args;
280 return 0;
281 }
282 /*
283 * XXX turn off async to avoid hangs when writing lots of data.
284 * the problem is that MFS needs to allocate pages to clean pages,
285 * so if we wait until the last minute to clean pages then there
286 * may not be any pages available to do the cleaning.
287 * ... and since the default partially-synchronous mode turns out
288 * to not be sufficient under heavy load, make it full synchronous.
289 */
290 mp->mnt_flag &= ~MNT_ASYNC;
291 mp->mnt_flag |= MNT_SYNCHRONOUS;
292
293 /*
294 * If updating, check whether changing from read-only to
295 * read/write; if there is no device name, that's all we do.
296 */
297 if (mp->mnt_flag & MNT_UPDATE) {
298 ump = VFSTOUFS(mp);
299 fs = ump->um_fs;
300 if (fs->fs_ronly == 0 && (mp->mnt_flag & MNT_RDONLY)) {
301 flags = WRITECLOSE;
302 if (mp->mnt_flag & MNT_FORCE)
303 flags |= FORCECLOSE;
304 error = ffs_flushfiles(mp, flags, l);
305 if (error)
306 return (error);
307 }
308 if (fs->fs_ronly && (mp->mnt_iflag & IMNT_WANTRDWR))
309 fs->fs_ronly = 0;
310 if (args->fspec == NULL)
311 return EINVAL;
312 return (0);
313 }
314 mutex_enter(&mfs_lock);
315 minor = mfs_minor++;
316 mutex_exit(&mfs_lock);
317 error = bdevvp(makedev(255, minor), &devvp);
318 if (error)
319 return (error);
320 mfsp = kmem_alloc(sizeof(*mfsp), KM_SLEEP);
321 /*
322 * Changing v_op and v_data here is safe as we are
323 * the exclusive owner of this device node.
324 */
325 KASSERT(devvp->v_op == spec_vnodeop_p);
326 KASSERT(devvp->v_data == NULL);
327 devvp->v_op = mfs_vnodeop_p;
328 devvp->v_data = mfsp;
329 mfsp->mfs_baseoff = args->base;
330 mfsp->mfs_size = args->size;
331 mfsp->mfs_vnode = devvp;
332 mfsp->mfs_proc = p;
333 mfsp->mfs_shutdown = 0;
334 cv_init(&mfsp->mfs_cv, "mfsidl");
335 mfsp->mfs_refcnt = 1;
336 bufq_alloc(&mfsp->mfs_buflist, "fcfs", 0);
337 if ((error = ffs_mountfs(devvp, mp, l)) != 0) {
338 mfsp->mfs_shutdown = 1;
339 vrele(devvp);
340 return (error);
341 }
342 ump = VFSTOUFS(mp);
343 fs = ump->um_fs;
344 error = set_statvfs_info(path, UIO_USERSPACE, args->fspec,
345 UIO_USERSPACE, mp->mnt_op->vfs_name, mp, l);
346 if (error)
347 return error;
348 (void)strncpy(fs->fs_fsmnt, mp->mnt_stat.f_mntonname,
349 sizeof(fs->fs_fsmnt));
350 fs->fs_fsmnt[sizeof(fs->fs_fsmnt) - 1] = '\0';
351 /* XXX: cleanup on error */
352 return 0;
353 }
354
355 /*
356 * Used to grab the process and keep it in the kernel to service
357 * memory filesystem I/O requests.
358 *
359 * Loop servicing I/O requests.
360 * Copy the requested data into or out of the memory filesystem
361 * address space.
362 */
363 /* ARGSUSED */
364 int
mfs_start(struct mount * mp,int flags)365 mfs_start(struct mount *mp, int flags)
366 {
367 struct vnode *vp;
368 struct mfsnode *mfsp;
369 struct proc *p;
370 struct buf *bp;
371 void *base;
372 int sleepreturn = 0, refcnt, error;
373 ksiginfoq_t kq;
374
375 /*
376 * Ensure that file system is still mounted when getting mfsnode.
377 * Add a reference to the mfsnode to prevent it disappearing in
378 * this routine.
379 */
380 if ((error = vfs_busy(mp)) != 0)
381 return error;
382 vp = VFSTOUFS(mp)->um_devvp;
383 mfsp = VTOMFS(vp);
384 mutex_enter(&mfs_lock);
385 mfsp->mfs_refcnt++;
386 mutex_exit(&mfs_lock);
387 vfs_unbusy(mp);
388
389 base = mfsp->mfs_baseoff;
390 mutex_enter(&mfs_lock);
391 while (mfsp->mfs_shutdown != 1) {
392 while ((bp = bufq_get(mfsp->mfs_buflist)) != NULL) {
393 mutex_exit(&mfs_lock);
394 mfs_doio(bp, base);
395 mutex_enter(&mfs_lock);
396 }
397 /*
398 * If a non-ignored signal is received, try to unmount.
399 * If that fails, or the filesystem is already in the
400 * process of being unmounted, clear the signal (it has been
401 * "processed"), otherwise we will loop here, as tsleep
402 * will always return EINTR/ERESTART.
403 */
404 if (sleepreturn != 0) {
405 mutex_exit(&mfs_lock);
406 if (dounmount(mp, 0, curlwp) != 0) {
407 p = curproc;
408 ksiginfo_queue_init(&kq);
409 mutex_enter(p->p_lock);
410 sigclearall(p, NULL, &kq);
411 mutex_exit(p->p_lock);
412 ksiginfo_queue_drain(&kq);
413 }
414 sleepreturn = 0;
415 mutex_enter(&mfs_lock);
416 continue;
417 }
418
419 sleepreturn = cv_wait_sig(&mfsp->mfs_cv, &mfs_lock);
420 }
421 KASSERT(bufq_peek(mfsp->mfs_buflist) == NULL);
422 refcnt = --mfsp->mfs_refcnt;
423 mutex_exit(&mfs_lock);
424 if (refcnt == 0) {
425 bufq_free(mfsp->mfs_buflist);
426 cv_destroy(&mfsp->mfs_cv);
427 kmem_free(mfsp, sizeof(*mfsp));
428 }
429 return (sleepreturn);
430 }
431
432 /*
433 * Get file system statistics.
434 */
435 int
mfs_statvfs(struct mount * mp,struct statvfs * sbp)436 mfs_statvfs(struct mount *mp, struct statvfs *sbp)
437 {
438 int error;
439
440 error = ffs_statvfs(mp, sbp);
441 if (error)
442 return error;
443 (void)strncpy(sbp->f_fstypename, mp->mnt_op->vfs_name,
444 sizeof(sbp->f_fstypename));
445 sbp->f_fstypename[sizeof(sbp->f_fstypename) - 1] = '\0';
446 return 0;
447 }
448