mfs_vfsops.c revision 1.92 
1/*	$NetBSD: mfs_vfsops.c,v 1.92 2008/04/24 18:39:25 ad 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 1.92 2008/04/24 18:39:25 ad 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
54#include <miscfs/genfs/genfs.h>
55#include <miscfs/specfs/specdev.h>
56#include <miscfs/syncfs/syncfs.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
69void *	mfs_rootbase;	/* address of mini-root in kernel virtual memory */
70u_long	mfs_rootsize;	/* size of mini-root in bytes */
71kmutex_t mfs_lock;	/* global lock */
72
73static int mfs_minor;	/* used for building internal dev_t */
74static int mfs_initcnt;
75
76extern int (**mfs_vnodeop_p)(void *);
77
78/*
79 * mfs vfs operations.
80 */
81
82extern const struct vnodeopv_desc mfs_vnodeop_opv_desc;
83
84const struct vnodeopv_desc * const mfs_vnodeopv_descs[] = {
85	&mfs_vnodeop_opv_desc,
86	NULL,
87};
88
89struct vfsops mfs_vfsops = {
90	MOUNT_MFS,
91	sizeof (struct mfs_args),
92	mfs_mount,
93	mfs_start,
94	ffs_unmount,
95	ufs_root,
96	ufs_quotactl,
97	mfs_statvfs,
98	ffs_sync,
99	ffs_vget,
100	ffs_fhtovp,
101	ffs_vptofh,
102	mfs_init,
103	mfs_reinit,
104	mfs_done,
105	NULL,
106	(int (*)(struct mount *, struct vnode *, struct timespec *)) eopnotsupp,
107	vfs_stdextattrctl,
108	(void *)eopnotsupp,	/* vfs_suspendctl */
109	genfs_renamelock_enter,
110	genfs_renamelock_exit,
111	mfs_vnodeopv_descs,
112	0,
113	{ NULL, NULL },
114};
115VFS_ATTACH(mfs_vfsops);
116
117SYSCTL_SETUP(sysctl_vfs_mfs_setup, "sysctl vfs.mfs subtree setup")
118{
119
120	sysctl_createv(clog, 0, NULL, NULL,
121		       CTLFLAG_PERMANENT,
122		       CTLTYPE_NODE, "vfs", NULL,
123		       NULL, 0, NULL, 0,
124		       CTL_VFS, CTL_EOL);
125	sysctl_createv(clog, 0, NULL, NULL,
126		       CTLFLAG_PERMANENT|CTLFLAG_ALIAS,
127		       CTLTYPE_NODE, "mfs",
128		       SYSCTL_DESCR("Memory based file system"),
129		       NULL, 1, NULL, 0,
130		       CTL_VFS, 3, CTL_EOL);
131	/*
132	 * XXX the "1" and the "3" above could be dynamic, thereby
133	 * eliminating one more instance of the "number to vfs"
134	 * mapping problem, but they are in order as taken from
135	 * sys/mount.h
136	 */
137}
138
139/*
140 * Memory based filesystem initialization.
141 */
142void
143mfs_init(void)
144{
145
146	if (mfs_initcnt++ == 0) {
147		mutex_init(&mfs_lock, MUTEX_DEFAULT, IPL_NONE);
148		ffs_init();
149	}
150}
151
152void
153mfs_reinit(void)
154{
155
156	ffs_reinit();
157}
158
159void
160mfs_done(void)
161{
162
163	if (--mfs_initcnt == 0) {
164		ffs_done();
165		mutex_destroy(&mfs_lock);
166	}
167}
168
169/*
170 * Called by main() when mfs is going to be mounted as root.
171 */
172
173int
174mfs_mountroot(void)
175{
176	struct fs *fs;
177	struct mount *mp;
178	struct lwp *l = curlwp;		/* XXX */
179	struct ufsmount *ump;
180	struct mfsnode *mfsp;
181	int error = 0;
182
183	if ((error = vfs_rootmountalloc(MOUNT_MFS, "mfs_root", &mp))) {
184		vrele(rootvp);
185		return (error);
186	}
187
188	mfsp = kmem_alloc(sizeof(*mfsp), KM_SLEEP);
189	rootvp->v_data = mfsp;
190	rootvp->v_op = mfs_vnodeop_p;
191	rootvp->v_tag = VT_MFS;
192	mfsp->mfs_baseoff = mfs_rootbase;
193	mfsp->mfs_size = mfs_rootsize;
194	mfsp->mfs_vnode = rootvp;
195	mfsp->mfs_proc = NULL;		/* indicate kernel space */
196	mfsp->mfs_shutdown = 0;
197	cv_init(&mfsp->mfs_cv, "mfs");
198	mfsp->mfs_refcnt = 1;
199	bufq_alloc(&mfsp->mfs_buflist, "fcfs", 0);
200	if ((error = ffs_mountfs(rootvp, mp, l)) != 0) {
201		vfs_unbusy(mp, false);
202		bufq_free(mfsp->mfs_buflist);
203		vfs_destroy(mp);
204		kmem_free(mfsp, sizeof(*mfsp));
205		return (error);
206	}
207	mutex_enter(&mountlist_lock);
208	CIRCLEQ_INSERT_TAIL(&mountlist, mp, mnt_list);
209	mutex_exit(&mountlist_lock);
210	mp->mnt_vnodecovered = NULLVP;
211	ump = VFSTOUFS(mp);
212	fs = ump->um_fs;
213	(void) copystr(mp->mnt_stat.f_mntonname, fs->fs_fsmnt, MNAMELEN - 1, 0);
214	(void)ffs_statvfs(mp, &mp->mnt_stat);
215	vfs_unbusy(mp, false);
216	return (0);
217}
218
219/*
220 * This is called early in boot to set the base address and size
221 * of the mini-root.
222 */
223int
224mfs_initminiroot(void *base)
225{
226	struct fs *fs = (struct fs *)((char *)base + SBLOCK_UFS1);
227
228	/* check for valid super block */
229	if (fs->fs_magic != FS_UFS1_MAGIC || fs->fs_bsize > MAXBSIZE ||
230	    fs->fs_bsize < sizeof(struct fs))
231		return (0);
232	mountroot = mfs_mountroot;
233	mfs_rootbase = base;
234	mfs_rootsize = fs->fs_fsize * fs->fs_size;
235	rootdev = makedev(255, mfs_minor);
236	mfs_minor++;
237	return (mfs_rootsize);
238}
239
240/*
241 * VFS Operations.
242 *
243 * mount system call
244 */
245/* ARGSUSED */
246int
247mfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len)
248{
249	struct lwp *l = curlwp;
250	struct vnode *devvp;
251	struct mfs_args *args = data;
252	struct ufsmount *ump;
253	struct fs *fs;
254	struct mfsnode *mfsp;
255	struct proc *p;
256	int flags, error = 0;
257
258	if (*data_len < sizeof *args)
259		return EINVAL;
260
261	p = l->l_proc;
262	if (mp->mnt_flag & MNT_GETARGS) {
263		struct vnode *vp;
264
265		ump = VFSTOUFS(mp);
266		if (ump == NULL)
267			return EIO;
268
269		vp = ump->um_devvp;
270		if (vp == NULL)
271			return EIO;
272
273		mfsp = VTOMFS(vp);
274		if (mfsp == NULL)
275			return EIO;
276
277		args->fspec = NULL;
278		args->base = mfsp->mfs_baseoff;
279		args->size = mfsp->mfs_size;
280		*data_len = sizeof *args;
281		return 0;
282	}
283	/*
284	 * XXX turn off async to avoid hangs when writing lots of data.
285	 * the problem is that MFS needs to allocate pages to clean pages,
286	 * so if we wait until the last minute to clean pages then there
287	 * may not be any pages available to do the cleaning.
288	 * ... and since the default partially-synchronous mode turns out
289	 * to not be sufficient under heavy load, make it full synchronous.
290	 */
291	mp->mnt_flag &= ~MNT_ASYNC;
292	mp->mnt_flag |= MNT_SYNCHRONOUS;
293
294	/*
295	 * If updating, check whether changing from read-only to
296	 * read/write; if there is no device name, that's all we do.
297	 */
298	if (mp->mnt_flag & MNT_UPDATE) {
299		ump = VFSTOUFS(mp);
300		fs = ump->um_fs;
301		if (fs->fs_ronly == 0 && (mp->mnt_flag & MNT_RDONLY)) {
302			flags = WRITECLOSE;
303			if (mp->mnt_flag & MNT_FORCE)
304				flags |= FORCECLOSE;
305			error = ffs_flushfiles(mp, flags, l);
306			if (error)
307				return (error);
308		}
309		if (fs->fs_ronly && (mp->mnt_iflag & IMNT_WANTRDWR))
310			fs->fs_ronly = 0;
311		if (args->fspec == NULL)
312			return EINVAL;
313		return (0);
314	}
315	error = getnewvnode(VT_MFS, (struct mount *)0, mfs_vnodeop_p, &devvp);
316	if (error)
317		return (error);
318	devvp->v_vflag |= VV_MPSAFE;
319	devvp->v_type = VBLK;
320	spec_node_init(devvp, makedev(255, mfs_minor));
321	mfs_minor++;
322	mfsp = kmem_alloc(sizeof(*mfsp), KM_SLEEP);
323	devvp->v_data = mfsp;
324	mfsp->mfs_baseoff = args->base;
325	mfsp->mfs_size = args->size;
326	mfsp->mfs_vnode = devvp;
327	mfsp->mfs_proc = p;
328	mfsp->mfs_shutdown = 0;
329	cv_init(&mfsp->mfs_cv, "mfsidl");
330	mfsp->mfs_refcnt = 1;
331	bufq_alloc(&mfsp->mfs_buflist, "fcfs", 0);
332	if ((error = ffs_mountfs(devvp, mp, l)) != 0) {
333		mfsp->mfs_shutdown = 1;
334		vrele(devvp);
335		return (error);
336	}
337	ump = VFSTOUFS(mp);
338	fs = ump->um_fs;
339	error = set_statvfs_info(path, UIO_USERSPACE, args->fspec,
340	    UIO_USERSPACE, mp->mnt_op->vfs_name, mp, l);
341	if (error)
342		return error;
343	(void)strncpy(fs->fs_fsmnt, mp->mnt_stat.f_mntonname,
344		sizeof(fs->fs_fsmnt));
345	fs->fs_fsmnt[sizeof(fs->fs_fsmnt) - 1] = '\0';
346	/* XXX: cleanup on error */
347	return 0;
348}
349
350/*
351 * Used to grab the process and keep it in the kernel to service
352 * memory filesystem I/O requests.
353 *
354 * Loop servicing I/O requests.
355 * Copy the requested data into or out of the memory filesystem
356 * address space.
357 */
358/* ARGSUSED */
359int
360mfs_start(struct mount *mp, int flags)
361{
362	struct vnode *vp;
363	struct mfsnode *mfsp;
364	struct proc *p;
365	struct buf *bp;
366	void *base;
367	int sleepreturn = 0, refcnt, error;
368	ksiginfoq_t kq;
369
370	/*
371	 * Ensure that file system is still mounted when getting mfsnode.
372	 * Add a reference to the mfsnode to prevent it disappearing in
373	 * this routine.
374	 */
375	if ((error = vfs_busy(mp, RW_READER, NULL)) != 0)
376		return error;
377	vp = VFSTOUFS(mp)->um_devvp;
378	mfsp = VTOMFS(vp);
379	mutex_enter(&mfs_lock);
380	mfsp->mfs_refcnt++;
381	mutex_exit(&mfs_lock);
382	vfs_unbusy(mp, false);
383
384	base = mfsp->mfs_baseoff;
385	mutex_enter(&mfs_lock);
386	while (mfsp->mfs_shutdown != 1) {
387		while ((bp = BUFQ_GET(mfsp->mfs_buflist)) != NULL) {
388			mutex_exit(&mfs_lock);
389			mfs_doio(bp, base);
390			mutex_enter(&mfs_lock);
391		}
392		/*
393		 * If a non-ignored signal is received, try to unmount.
394		 * If that fails, or the filesystem is already in the
395		 * process of being unmounted, clear the signal (it has been
396		 * "processed"), otherwise we will loop here, as tsleep
397		 * will always return EINTR/ERESTART.
398		 */
399		if (sleepreturn != 0) {
400			mutex_exit(&mfs_lock);
401			/*
402			 * XXX Freeze syncer.  Must do this before locking
403			 * the mount point.  See dounmount() for details.
404			 */
405			mutex_enter(&syncer_mutex);
406			if (vfs_trybusy(mp, RW_WRITER, NULL) != 0)
407				mutex_exit(&syncer_mutex);
408			else if (dounmount(mp, 0, curlwp) != 0) {
409				p = curproc;
410				ksiginfo_queue_init(&kq);
411				mutex_enter(p->p_lock);
412				sigclearall(p, NULL, &kq);
413				mutex_exit(p->p_lock);
414				ksiginfo_queue_drain(&kq);
415			}
416			sleepreturn = 0;
417			mutex_enter(&mfs_lock);
418			continue;
419		}
420
421		sleepreturn = cv_wait_sig(&mfsp->mfs_cv, &mfs_lock);
422	}
423	KASSERT(BUFQ_PEEK(mfsp->mfs_buflist) == NULL);
424	refcnt = --mfsp->mfs_refcnt;
425	mutex_exit(&mfs_lock);
426	if (refcnt == 0) {
427		bufq_free(mfsp->mfs_buflist);
428		cv_destroy(&mfsp->mfs_cv);
429		kmem_free(mfsp, sizeof(*mfsp));
430	}
431	return (sleepreturn);
432}
433
434/*
435 * Get file system statistics.
436 */
437int
438mfs_statvfs(struct mount *mp, struct statvfs *sbp)
439{
440	int error;
441
442	error = ffs_statvfs(mp, sbp);
443	if (error)
444		return error;
445	(void)strncpy(sbp->f_fstypename, mp->mnt_op->vfs_name,
446	    sizeof(sbp->f_fstypename));
447	sbp->f_fstypename[sizeof(sbp->f_fstypename) - 1] = '\0';
448	return 0;
449}
450