mfs_vfsops.c revision 1.113 
1/*	$NetBSD: mfs_vfsops.c,v 1.113 2017/04/17 08:32:02 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 1.113 2017/04/17 08:32:02 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
69MODULE(MODULE_CLASS_VFS, mfs, "ffs");
70
71kmutex_t mfs_lock;	/* global lock */
72
73/* used for building internal dev_t, minor == 0 reserved for miniroot */
74static devminor_t mfs_minor = 1;
75static int mfs_initcnt;
76
77extern int (**mfs_vnodeop_p)(void *);
78
79static struct sysctllog *mfs_sysctl_log;
80
81/*
82 * mfs vfs operations.
83 */
84
85extern const struct vnodeopv_desc mfs_vnodeop_opv_desc;
86
87const struct vnodeopv_desc * const mfs_vnodeopv_descs[] = {
88	&mfs_vnodeop_opv_desc,
89	NULL,
90};
91
92struct vfsops mfs_vfsops = {
93	.vfs_name = MOUNT_MFS,
94	.vfs_min_mount_data = sizeof (struct mfs_args),
95	.vfs_mount = mfs_mount,
96	.vfs_start = mfs_start,
97	.vfs_unmount = ffs_unmount,
98	.vfs_root = ufs_root,
99	.vfs_quotactl = ufs_quotactl,
100	.vfs_statvfs = mfs_statvfs,
101	.vfs_sync = ffs_sync,
102	.vfs_vget = ufs_vget,
103	.vfs_loadvnode = ffs_loadvnode,
104	.vfs_newvnode = ffs_newvnode,
105	.vfs_fhtovp = ffs_fhtovp,
106	.vfs_vptofh = ffs_vptofh,
107	.vfs_init = mfs_init,
108	.vfs_reinit = mfs_reinit,
109	.vfs_done = mfs_done,
110	.vfs_snapshot = (void *)eopnotsupp,
111	.vfs_extattrctl = vfs_stdextattrctl,
112	.vfs_suspendctl = genfs_suspendctl,
113	.vfs_renamelock_enter = genfs_renamelock_enter,
114	.vfs_renamelock_exit = genfs_renamelock_exit,
115	.vfs_fsync = (void *)eopnotsupp,
116	.vfs_opv_descs = mfs_vnodeopv_descs
117};
118
119static int
120mfs_modcmd(modcmd_t cmd, void *arg)
121{
122	int error;
123
124	switch (cmd) {
125	case MODULE_CMD_INIT:
126		error = vfs_attach(&mfs_vfsops);
127		if (error != 0)
128			break;
129		sysctl_createv(&mfs_sysctl_log, 0, NULL, NULL,
130			       CTLFLAG_PERMANENT|CTLFLAG_ALIAS,
131			       CTLTYPE_NODE, "mfs",
132			       SYSCTL_DESCR("Memory based file system"),
133			       NULL, 1, NULL, 0,
134			       CTL_VFS, 3, CTL_EOL);
135		/*
136		 * XXX the "1" and the "3" above could be dynamic, thereby
137		 * eliminating one more instance of the "number to vfs"
138		 * mapping problem, but they are in order as taken from
139		 * sys/mount.h
140		 */
141		break;
142	case MODULE_CMD_FINI:
143		error = vfs_detach(&mfs_vfsops);
144		if (error != 0)
145			break;
146		sysctl_teardown(&mfs_sysctl_log);
147		break;
148	default:
149		error = ENOTTY;
150		break;
151	}
152
153	return (error);
154}
155
156/*
157 * Memory based filesystem initialization.
158 */
159void
160mfs_init(void)
161{
162
163	if (mfs_initcnt++ == 0) {
164		mutex_init(&mfs_lock, MUTEX_DEFAULT, IPL_NONE);
165		ffs_init();
166	}
167}
168
169void
170mfs_reinit(void)
171{
172
173	ffs_reinit();
174}
175
176void
177mfs_done(void)
178{
179
180	if (--mfs_initcnt == 0) {
181		ffs_done();
182		mutex_destroy(&mfs_lock);
183	}
184}
185
186/*
187 * Called by main() when mfs is going to be mounted as root.
188 */
189
190int
191mfs_mountroot(void)
192{
193	struct fs *fs;
194	struct mount *mp;
195	struct lwp *l = curlwp;		/* XXX */
196	struct ufsmount *ump;
197	struct mfsnode *mfsp;
198	int error = 0;
199
200	if ((error = vfs_rootmountalloc(MOUNT_MFS, "mfs_root", &mp))) {
201		vrele(rootvp);
202		return (error);
203	}
204
205	mfsp = kmem_alloc(sizeof(*mfsp), KM_SLEEP);
206	rootvp->v_data = mfsp;
207	rootvp->v_op = mfs_vnodeop_p;
208	rootvp->v_tag = VT_MFS;
209	mfsp->mfs_baseoff = mfs_rootbase;
210	mfsp->mfs_size = mfs_rootsize;
211	mfsp->mfs_vnode = rootvp;
212	mfsp->mfs_proc = NULL;		/* indicate kernel space */
213	mfsp->mfs_shutdown = 0;
214	cv_init(&mfsp->mfs_cv, "mfs");
215	mfsp->mfs_refcnt = 1;
216	bufq_alloc(&mfsp->mfs_buflist, "fcfs", 0);
217	if ((error = ffs_mountfs(rootvp, mp, l)) != 0) {
218		vfs_unbusy(mp);
219		bufq_free(mfsp->mfs_buflist);
220		vfs_rele(mp);
221		kmem_free(mfsp, sizeof(*mfsp));
222		return (error);
223	}
224	mountlist_append(mp);
225	mp->mnt_vnodecovered = NULLVP;
226	ump = VFSTOUFS(mp);
227	fs = ump->um_fs;
228	(void) copystr(mp->mnt_stat.f_mntonname, fs->fs_fsmnt, MNAMELEN - 1, 0);
229	(void)ffs_statvfs(mp, &mp->mnt_stat);
230	vfs_unbusy(mp);
231	return (0);
232}
233
234/*
235 * VFS Operations.
236 *
237 * mount system call
238 */
239/* ARGSUSED */
240int
241mfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len)
242{
243	struct lwp *l = curlwp;
244	struct vnode *devvp;
245	struct mfs_args *args = data;
246	struct ufsmount *ump;
247	struct fs *fs;
248	struct mfsnode *mfsp;
249	struct proc *p;
250	devminor_t minor;
251	int flags, error = 0;
252
253	if (args == NULL)
254		return EINVAL;
255	if (*data_len < sizeof *args)
256		return EINVAL;
257
258	p = l->l_proc;
259	if (mp->mnt_flag & MNT_GETARGS) {
260		struct vnode *vp;
261
262		ump = VFSTOUFS(mp);
263		if (ump == NULL)
264			return EIO;
265
266		vp = ump->um_devvp;
267		if (vp == NULL)
268			return EIO;
269
270		mfsp = VTOMFS(vp);
271		if (mfsp == NULL)
272			return EIO;
273
274		args->fspec = NULL;
275		args->base = mfsp->mfs_baseoff;
276		args->size = mfsp->mfs_size;
277		*data_len = sizeof *args;
278		return 0;
279	}
280	/*
281	 * XXX turn off async to avoid hangs when writing lots of data.
282	 * the problem is that MFS needs to allocate pages to clean pages,
283	 * so if we wait until the last minute to clean pages then there
284	 * may not be any pages available to do the cleaning.
285	 * ... and since the default partially-synchronous mode turns out
286	 * to not be sufficient under heavy load, make it full synchronous.
287	 */
288	mp->mnt_flag &= ~MNT_ASYNC;
289	mp->mnt_flag |= MNT_SYNCHRONOUS;
290
291	/*
292	 * If updating, check whether changing from read-only to
293	 * read/write; if there is no device name, that's all we do.
294	 */
295	if (mp->mnt_flag & MNT_UPDATE) {
296		ump = VFSTOUFS(mp);
297		fs = ump->um_fs;
298		if (fs->fs_ronly == 0 && (mp->mnt_flag & MNT_RDONLY)) {
299			flags = WRITECLOSE;
300			if (mp->mnt_flag & MNT_FORCE)
301				flags |= FORCECLOSE;
302			error = ffs_flushfiles(mp, flags, l);
303			if (error)
304				return (error);
305		}
306		if (fs->fs_ronly && (mp->mnt_iflag & IMNT_WANTRDWR))
307			fs->fs_ronly = 0;
308		if (args->fspec == NULL)
309			return EINVAL;
310		return (0);
311	}
312	mutex_enter(&mfs_lock);
313	minor = mfs_minor++;
314	mutex_exit(&mfs_lock);
315	error = bdevvp(makedev(255, minor), &devvp);
316	if (error)
317		return (error);
318	mfsp = kmem_alloc(sizeof(*mfsp), KM_SLEEP);
319	/*
320	 * Changing v_op and v_data here is safe as we are
321	 * the exclusive owner of this device node.
322	 */
323	KASSERT(devvp->v_op == spec_vnodeop_p);
324	KASSERT(devvp->v_data == NULL);
325	devvp->v_op = mfs_vnodeop_p;
326	devvp->v_data = mfsp;
327	mfsp->mfs_baseoff = args->base;
328	mfsp->mfs_size = args->size;
329	mfsp->mfs_vnode = devvp;
330	mfsp->mfs_proc = p;
331	mfsp->mfs_shutdown = 0;
332	cv_init(&mfsp->mfs_cv, "mfsidl");
333	mfsp->mfs_refcnt = 1;
334	bufq_alloc(&mfsp->mfs_buflist, "fcfs", 0);
335	if ((error = ffs_mountfs(devvp, mp, l)) != 0) {
336		mfsp->mfs_shutdown = 1;
337		vrele(devvp);
338		return (error);
339	}
340	ump = VFSTOUFS(mp);
341	fs = ump->um_fs;
342	error = set_statvfs_info(path, UIO_USERSPACE, args->fspec,
343	    UIO_USERSPACE, mp->mnt_op->vfs_name, mp, l);
344	if (error)
345		return error;
346	(void)strncpy(fs->fs_fsmnt, mp->mnt_stat.f_mntonname,
347		sizeof(fs->fs_fsmnt));
348	fs->fs_fsmnt[sizeof(fs->fs_fsmnt) - 1] = '\0';
349	/* XXX: cleanup on error */
350	return 0;
351}
352
353/*
354 * Used to grab the process and keep it in the kernel to service
355 * memory filesystem I/O requests.
356 *
357 * Loop servicing I/O requests.
358 * Copy the requested data into or out of the memory filesystem
359 * address space.
360 */
361/* ARGSUSED */
362int
363mfs_start(struct mount *mp, int flags)
364{
365	struct vnode *vp;
366	struct mfsnode *mfsp;
367	struct proc *p;
368	struct buf *bp;
369	void *base;
370	int sleepreturn = 0, refcnt, error;
371	ksiginfoq_t kq;
372
373	/*
374	 * Ensure that file system is still mounted when getting mfsnode.
375	 * Add a reference to the mfsnode to prevent it disappearing in
376	 * this routine.
377	 */
378	if ((error = vfs_busy(mp)) != 0)
379		return error;
380	vp = VFSTOUFS(mp)->um_devvp;
381	mfsp = VTOMFS(vp);
382	mutex_enter(&mfs_lock);
383	mfsp->mfs_refcnt++;
384	mutex_exit(&mfs_lock);
385	vfs_unbusy(mp);
386
387	base = mfsp->mfs_baseoff;
388	mutex_enter(&mfs_lock);
389	while (mfsp->mfs_shutdown != 1) {
390		while ((bp = bufq_get(mfsp->mfs_buflist)) != NULL) {
391			mutex_exit(&mfs_lock);
392			mfs_doio(bp, base);
393			mutex_enter(&mfs_lock);
394		}
395		/*
396		 * If a non-ignored signal is received, try to unmount.
397		 * If that fails, or the filesystem is already in the
398		 * process of being unmounted, clear the signal (it has been
399		 * "processed"), otherwise we will loop here, as tsleep
400		 * will always return EINTR/ERESTART.
401		 */
402		if (sleepreturn != 0) {
403			mutex_exit(&mfs_lock);
404			if (dounmount(mp, 0, curlwp) != 0) {
405				p = curproc;
406				ksiginfo_queue_init(&kq);
407				mutex_enter(p->p_lock);
408				sigclearall(p, NULL, &kq);
409				mutex_exit(p->p_lock);
410				ksiginfo_queue_drain(&kq);
411			}
412			sleepreturn = 0;
413			mutex_enter(&mfs_lock);
414			continue;
415		}
416
417		sleepreturn = cv_wait_sig(&mfsp->mfs_cv, &mfs_lock);
418	}
419	KASSERT(bufq_peek(mfsp->mfs_buflist) == NULL);
420	refcnt = --mfsp->mfs_refcnt;
421	mutex_exit(&mfs_lock);
422	if (refcnt == 0) {
423		bufq_free(mfsp->mfs_buflist);
424		cv_destroy(&mfsp->mfs_cv);
425		kmem_free(mfsp, sizeof(*mfsp));
426	}
427	return (sleepreturn);
428}
429
430/*
431 * Get file system statistics.
432 */
433int
434mfs_statvfs(struct mount *mp, struct statvfs *sbp)
435{
436	int error;
437
438	error = ffs_statvfs(mp, sbp);
439	if (error)
440		return error;
441	(void)strncpy(sbp->f_fstypename, mp->mnt_op->vfs_name,
442	    sizeof(sbp->f_fstypename));
443	sbp->f_fstypename[sizeof(sbp->f_fstypename) - 1] = '\0';
444	return 0;
445}
446