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[netbsd-mini2440.git] / sys / dev / fss.c
blob401446e30b9e5cff7bf8c6877d19192ba8ae9f74
1 /* $NetBSD: fss.c,v 1.64 2009/10/13 12:37:19 hannken Exp $ */
2
3 /*-
4 * Copyright (c) 2003 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Juergen Hannken-Illjes.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32 /*
33 * File system snapshot disk driver.
34 *
35 * Block/character interface to the snapshot of a mounted file system.
36 */
37
38 #include <sys/cdefs.h>
39 __KERNEL_RCSID(0, "$NetBSD: fss.c,v 1.64 2009/10/13 12:37:19 hannken Exp $");
40
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #include <sys/namei.h>
44 #include <sys/proc.h>
45 #include <sys/errno.h>
46 #include <sys/malloc.h>
47 #include <sys/buf.h>
48 #include <sys/ioctl.h>
49 #include <sys/disklabel.h>
50 #include <sys/device.h>
51 #include <sys/disk.h>
52 #include <sys/stat.h>
53 #include <sys/mount.h>
54 #include <sys/vnode.h>
55 #include <sys/file.h>
56 #include <sys/uio.h>
57 #include <sys/conf.h>
58 #include <sys/kthread.h>
59 #include <sys/fstrans.h>
60 #include <sys/simplelock.h>
61
62 #include <miscfs/specfs/specdev.h>
63
64 #include <dev/fssvar.h>
65
66 #include <uvm/uvm.h>
67
68 void fssattach(int);
69
70 dev_type_open(fss_open);
71 dev_type_close(fss_close);
72 dev_type_read(fss_read);
73 dev_type_write(fss_write);
74 dev_type_ioctl(fss_ioctl);
75 dev_type_strategy(fss_strategy);
76 dev_type_dump(fss_dump);
77 dev_type_size(fss_size);
78
79 static void fss_unmount_hook(struct mount *);
80 static int fss_copy_on_write(void *, struct buf *, bool);
81 static inline void fss_error(struct fss_softc *, const char *);
82 static int fss_create_files(struct fss_softc *, struct fss_set *,
83 off_t *, struct lwp *);
84 static int fss_create_snapshot(struct fss_softc *, struct fss_set *,
85 struct lwp *);
86 static int fss_delete_snapshot(struct fss_softc *, struct lwp *);
87 static int fss_softc_alloc(struct fss_softc *);
88 static void fss_softc_free(struct fss_softc *);
89 static int fss_read_cluster(struct fss_softc *, u_int32_t);
90 static void fss_bs_thread(void *);
91 static int fss_bs_io(struct fss_softc *, fss_io_type,
92 u_int32_t, off_t, int, void *);
93 static u_int32_t *fss_bs_indir(struct fss_softc *, u_int32_t);
94
95 static kmutex_t fss_device_lock; /* Protect all units. */
96 static int fss_num_attached = 0; /* Number of attached devices. */
97 static struct vfs_hooks fss_vfs_hooks = {
98 .vh_unmount = fss_unmount_hook
99 };
100
101 const struct bdevsw fss_bdevsw = {
102 fss_open, fss_close, fss_strategy, fss_ioctl,
103 fss_dump, fss_size, D_DISK | D_MPSAFE
104 };
105
106 const struct cdevsw fss_cdevsw = {
107 fss_open, fss_close, fss_read, fss_write, fss_ioctl,
108 nostop, notty, nopoll, nommap, nokqfilter, D_DISK | D_MPSAFE
109 };
110
111 static int fss_match(device_t, cfdata_t, void *);
112 static void fss_attach(device_t, device_t, void *);
113 static int fss_detach(device_t, int);
114
115 CFATTACH_DECL_NEW(fss, sizeof(struct fss_softc),
116 fss_match, fss_attach, fss_detach, NULL);
117 extern struct cfdriver fss_cd;
118
119 void
120 fssattach(int num)
121 {
122
123 mutex_init(&fss_device_lock, MUTEX_DEFAULT, IPL_NONE);
124 if (config_cfattach_attach(fss_cd.cd_name, &fss_ca))
125 aprint_error("%s: unable to register\n", fss_cd.cd_name);
126 }
127
128 static int
129 fss_match(device_t self, cfdata_t cfdata, void *aux)
130 {
131 return 1;
132 }
133
134 static void
135 fss_attach(device_t parent, device_t self, void *aux)
136 {
137 struct fss_softc *sc = device_private(self);
138
139 sc->sc_dev = self;
140 sc->sc_bdev = NODEV;
141 mutex_init(&sc->sc_slock, MUTEX_DEFAULT, IPL_NONE);
142 mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_NONE);
143 cv_init(&sc->sc_work_cv, "fssbs");
144 cv_init(&sc->sc_cache_cv, "cowwait");
145 bufq_alloc(&sc->sc_bufq, "fcfs", 0);
146 sc->sc_dkdev = malloc(sizeof(*sc->sc_dkdev), M_DEVBUF, M_WAITOK);
147 sc->sc_dkdev->dk_info = NULL;
148 disk_init(sc->sc_dkdev, device_xname(self), NULL);
149 if (!pmf_device_register(self, NULL, NULL))
150 aprint_error_dev(self, "couldn't establish power handler\n");
151
152 if (fss_num_attached++ == 0)
153 vfs_hooks_attach(&fss_vfs_hooks);
154 }
155
156 static int
157 fss_detach(device_t self, int flags)
158 {
159 struct fss_softc *sc = device_private(self);
160
161 if (sc->sc_flags & FSS_ACTIVE)
162 return EBUSY;
163
164 if (--fss_num_attached == 0)
165 vfs_hooks_detach(&fss_vfs_hooks);
166
167 pmf_device_deregister(self);
168 mutex_destroy(&sc->sc_slock);
169 mutex_destroy(&sc->sc_lock);
170 cv_destroy(&sc->sc_work_cv);
171 cv_destroy(&sc->sc_cache_cv);
172 bufq_drain(sc->sc_bufq);
173 bufq_free(sc->sc_bufq);
174 disk_destroy(sc->sc_dkdev);
175 free(sc->sc_dkdev, M_DEVBUF);
176
177 return 0;
178 }
179
180 int
181 fss_open(dev_t dev, int flags, int mode, struct lwp *l)
182 {
183 int mflag;
184 cfdata_t cf;
185 struct fss_softc *sc;
186
187 mflag = (mode == S_IFCHR ? FSS_CDEV_OPEN : FSS_BDEV_OPEN);
188
189 mutex_enter(&fss_device_lock);
190
191 sc = device_lookup_private(&fss_cd, minor(dev));
192 if (sc == NULL) {
193 cf = malloc(sizeof(*cf), M_DEVBUF, M_WAITOK);
194 cf->cf_name = fss_cd.cd_name;
195 cf->cf_atname = fss_cd.cd_name;
196 cf->cf_unit = minor(dev);
197 cf->cf_fstate = FSTATE_STAR;
198 sc = device_private(config_attach_pseudo(cf));
199 if (sc == NULL)
200 return ENOMEM;
201 }
202
203 mutex_enter(&sc->sc_slock);
204
205 sc->sc_flags |= mflag;
206
207 mutex_exit(&sc->sc_slock);
208 mutex_exit(&fss_device_lock);
209
210 return 0;
211 }
212
213 int
214 fss_close(dev_t dev, int flags, int mode, struct lwp *l)
215 {
216 int mflag, error;
217 cfdata_t cf;
218 struct fss_softc *sc = device_lookup_private(&fss_cd, minor(dev));
219
220 mflag = (mode == S_IFCHR ? FSS_CDEV_OPEN : FSS_BDEV_OPEN);
221 error = 0;
222
223 restart:
224 mutex_enter(&sc->sc_slock);
225 if ((sc->sc_flags & (FSS_CDEV_OPEN|FSS_BDEV_OPEN)) != mflag) {
226 sc->sc_flags &= ~mflag;
227 mutex_exit(&sc->sc_slock);
228 return 0;
229 }
230 if ((sc->sc_flags & FSS_ACTIVE) != 0 &&
231 (sc->sc_uflags & FSS_UNCONFIG_ON_CLOSE) != 0) {
232 sc->sc_uflags &= ~FSS_UNCONFIG_ON_CLOSE;
233 mutex_exit(&sc->sc_slock);
234 error = fss_ioctl(dev, FSSIOCCLR, NULL, FWRITE, l);
235 goto restart;
236 }
237 if ((sc->sc_flags & FSS_ACTIVE) != 0) {
238 mutex_exit(&sc->sc_slock);
239 return error;
240 }
241 if (! mutex_tryenter(&fss_device_lock)) {
242 mutex_exit(&sc->sc_slock);
243 goto restart;
244 }
245
246 KASSERT((sc->sc_flags & FSS_ACTIVE) == 0);
247 KASSERT((sc->sc_flags & (FSS_CDEV_OPEN|FSS_BDEV_OPEN)) == mflag);
248 mutex_exit(&sc->sc_slock);
249 cf = device_cfdata(sc->sc_dev);
250 error = config_detach(sc->sc_dev, DETACH_QUIET);
251 if (! error)
252 free(cf, M_DEVBUF);
253 mutex_exit(&fss_device_lock);
254
255 return error;
256 }
257
258 void
259 fss_strategy(struct buf *bp)
260 {
261 const bool write = ((bp->b_flags & B_READ) != B_READ);
262 struct fss_softc *sc = device_lookup_private(&fss_cd, minor(bp->b_dev));
263
264 mutex_enter(&sc->sc_slock);
265
266 if (write || !FSS_ISVALID(sc)) {
267
268 mutex_exit(&sc->sc_slock);
269
270 bp->b_error = (write ? EROFS : ENXIO);
271 bp->b_resid = bp->b_bcount;
272 biodone(bp);
273 return;
274 }
275
276 bp->b_rawblkno = bp->b_blkno;
277 bufq_put(sc->sc_bufq, bp);
278 cv_signal(&sc->sc_work_cv);
279
280 mutex_exit(&sc->sc_slock);
281 }
282
283 int
284 fss_read(dev_t dev, struct uio *uio, int flags)
285 {
286 return physio(fss_strategy, NULL, dev, B_READ, minphys, uio);
287 }
288
289 int
290 fss_write(dev_t dev, struct uio *uio, int flags)
291 {
292 return physio(fss_strategy, NULL, dev, B_WRITE, minphys, uio);
293 }
294
295 int
296 fss_ioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l)
297 {
298 int error;
299 struct fss_softc *sc = device_lookup_private(&fss_cd, minor(dev));
300 struct fss_set *fss = (struct fss_set *)data;
301 struct fss_get *fsg = (struct fss_get *)data;
302
303 switch (cmd) {
304 case FSSIOCSET:
305 mutex_enter(&sc->sc_lock);
306 if ((flag & FWRITE) == 0)
307 error = EPERM;
308 else if ((sc->sc_flags & FSS_ACTIVE) != 0)
309 error = EBUSY;
310 else
311 error = fss_create_snapshot(sc, fss, l);
312 mutex_exit(&sc->sc_lock);
313 break;
314
315 case FSSIOCCLR:
316 mutex_enter(&sc->sc_lock);
317 if ((flag & FWRITE) == 0)
318 error = EPERM;
319 else if ((sc->sc_flags & FSS_ACTIVE) == 0)
320 error = ENXIO;
321 else
322 error = fss_delete_snapshot(sc, l);
323 mutex_exit(&sc->sc_lock);
324 break;
325
326 case FSSIOCGET:
327 mutex_enter(&sc->sc_lock);
328 switch (sc->sc_flags & (FSS_PERSISTENT | FSS_ACTIVE)) {
329 case FSS_ACTIVE:
330 memcpy(fsg->fsg_mount, sc->sc_mntname, MNAMELEN);
331 fsg->fsg_csize = FSS_CLSIZE(sc);
332 fsg->fsg_time = sc->sc_time;
333 fsg->fsg_mount_size = sc->sc_clcount;
334 fsg->fsg_bs_size = sc->sc_clnext;
335 error = 0;
336 break;
337 case FSS_PERSISTENT | FSS_ACTIVE:
338 memcpy(fsg->fsg_mount, sc->sc_mntname, MNAMELEN);
339 fsg->fsg_csize = 0;
340 fsg->fsg_time = sc->sc_time;
341 fsg->fsg_mount_size = 0;
342 fsg->fsg_bs_size = 0;
343 error = 0;
344 break;
345 default:
346 error = ENXIO;
347 break;
348 }
349 mutex_exit(&sc->sc_lock);
350 break;
351
352 case FSSIOFSET:
353 mutex_enter(&sc->sc_slock);
354 sc->sc_uflags = *(int *)data;
355 mutex_exit(&sc->sc_slock);
356 error = 0;
357 break;
358
359 case FSSIOFGET:
360 mutex_enter(&sc->sc_slock);
361 *(int *)data = sc->sc_uflags;
362 mutex_exit(&sc->sc_slock);
363 error = 0;
364 break;
365
366 default:
367 error = EINVAL;
368 break;
369 }
370
371 return error;
372 }
373
374 int
375 fss_size(dev_t dev)
376 {
377 return -1;
378 }
379
380 int
381 fss_dump(dev_t dev, daddr_t blkno, void *va,
382 size_t size)
383 {
384 return EROFS;
385 }
386
387 /*
388 * An error occurred reading or writing the snapshot or backing store.
389 * If it is the first error log to console.
390 * The caller holds the mutex.
391 */
392 static inline void
393 fss_error(struct fss_softc *sc, const char *msg)
394 {
395
396 if ((sc->sc_flags & (FSS_ACTIVE|FSS_ERROR)) == FSS_ACTIVE)
397 aprint_error_dev(sc->sc_dev, "snapshot invalid: %s\n", msg);
398 if ((sc->sc_flags & FSS_ACTIVE) == FSS_ACTIVE)
399 sc->sc_flags |= FSS_ERROR;
400 }
401
402 /*
403 * Allocate the variable sized parts of the softc and
404 * fork the kernel thread.
405 *
406 * The fields sc_clcount, sc_clshift, sc_cache_size and sc_indir_size
407 * must be initialized.
408 */
409 static int
410 fss_softc_alloc(struct fss_softc *sc)
411 {
412 int i, error;
413
414 if ((sc->sc_flags & FSS_PERSISTENT) == 0) {
415 sc->sc_copied =
416 kmem_zalloc(howmany(sc->sc_clcount, NBBY), KM_SLEEP);
417 if (sc->sc_copied == NULL)
418 return(ENOMEM);
419
420 sc->sc_cache = kmem_alloc(sc->sc_cache_size *
421 sizeof(struct fss_cache), KM_SLEEP);
422 if (sc->sc_cache == NULL)
423 return(ENOMEM);
424
425 for (i = 0; i < sc->sc_cache_size; i++) {
426 sc->sc_cache[i].fc_type = FSS_CACHE_FREE;
427 sc->sc_cache[i].fc_data =
428 kmem_alloc(FSS_CLSIZE(sc), KM_SLEEP);
429 if (sc->sc_cache[i].fc_data == NULL)
430 return(ENOMEM);
431 cv_init(&sc->sc_cache[i].fc_state_cv, "cowwait1");
432 }
433
434 sc->sc_indir_valid =
435 kmem_zalloc(howmany(sc->sc_indir_size, NBBY), KM_SLEEP);
436 if (sc->sc_indir_valid == NULL)
437 return(ENOMEM);
438
439 sc->sc_indir_data = kmem_zalloc(FSS_CLSIZE(sc), KM_SLEEP);
440 if (sc->sc_indir_data == NULL)
441 return(ENOMEM);
442 } else {
443 sc->sc_copied = NULL;
444 sc->sc_cache = NULL;
445 sc->sc_indir_valid = NULL;
446 sc->sc_indir_data = NULL;
447 }
448
449 sc->sc_flags |= FSS_BS_THREAD;
450 if ((error = kthread_create(PRI_BIO, 0, NULL, fss_bs_thread, sc,
451 &sc->sc_bs_lwp, device_xname(sc->sc_dev))) != 0) {
452 sc->sc_flags &= ~FSS_BS_THREAD;
453 return error;
454 }
455
456 disk_attach(sc->sc_dkdev);
457
458 return 0;
459 }
460
461 /*
462 * Free the variable sized parts of the softc.
463 */
464 static void
465 fss_softc_free(struct fss_softc *sc)
466 {
467 int i;
468
469 if ((sc->sc_flags & FSS_BS_THREAD) != 0) {
470 mutex_enter(&sc->sc_slock);
471 sc->sc_flags &= ~FSS_BS_THREAD;
472 cv_signal(&sc->sc_work_cv);
473 while (sc->sc_bs_lwp != NULL)
474 kpause("fssdetach", false, 1, &sc->sc_slock);
475 mutex_exit(&sc->sc_slock);
476 }
477
478 disk_detach(sc->sc_dkdev);
479
480 if (sc->sc_copied != NULL)
481 kmem_free(sc->sc_copied, howmany(sc->sc_clcount, NBBY));
482 sc->sc_copied = NULL;
483
484 if (sc->sc_cache != NULL) {
485 for (i = 0; i < sc->sc_cache_size; i++)
486 if (sc->sc_cache[i].fc_data != NULL) {
487 cv_destroy(&sc->sc_cache[i].fc_state_cv);
488 kmem_free(sc->sc_cache[i].fc_data,
489 FSS_CLSIZE(sc));
490 }
491 kmem_free(sc->sc_cache,
492 sc->sc_cache_size*sizeof(struct fss_cache));
493 }
494 sc->sc_cache = NULL;
495
496 if (sc->sc_indir_valid != NULL)
497 kmem_free(sc->sc_indir_valid, howmany(sc->sc_indir_size, NBBY));
498 sc->sc_indir_valid = NULL;
499
500 if (sc->sc_indir_data != NULL)
501 kmem_free(sc->sc_indir_data, FSS_CLSIZE(sc));
502 sc->sc_indir_data = NULL;
503 }
504
505 /*
506 * Set all active snapshots on this file system into ERROR state.
507 */
508 static void
509 fss_unmount_hook(struct mount *mp)
510 {
511 int i;
512 struct fss_softc *sc;
513
514 mutex_enter(&fss_device_lock);
515 for (i = 0; i < fss_cd.cd_ndevs; i++) {
516 if ((sc = device_lookup_private(&fss_cd, i)) == NULL)
517 continue;
518 mutex_enter(&sc->sc_slock);
519 if ((sc->sc_flags & FSS_ACTIVE) != 0 &&
520 sc->sc_mount == mp)
521 fss_error(sc, "forced unmount");
522 mutex_exit(&sc->sc_slock);
523 }
524 mutex_exit(&fss_device_lock);
525 }
526
527 /*
528 * A buffer is written to the snapshotted block device. Copy to
529 * backing store if needed.
530 */
531 static int
532 fss_copy_on_write(void *v, struct buf *bp, bool data_valid)
533 {
534 int error;
535 u_int32_t cl, ch, c;
536 struct fss_softc *sc = v;
537
538 mutex_enter(&sc->sc_slock);
539 if (!FSS_ISVALID(sc)) {
540 mutex_exit(&sc->sc_slock);
541 return 0;
542 }
543
544 cl = FSS_BTOCL(sc, dbtob(bp->b_blkno));
545 ch = FSS_BTOCL(sc, dbtob(bp->b_blkno)+bp->b_bcount-1);
546 error = 0;
547 if (curlwp == uvm.pagedaemon_lwp) {
548 for (c = cl; c <= ch; c++)
549 if (isclr(sc->sc_copied, c)) {
550 error = ENOMEM;
551 break;
552 }
553 }
554 mutex_exit(&sc->sc_slock);
555
556 if (error == 0)
557 for (c = cl; c <= ch; c++) {
558 error = fss_read_cluster(sc, c);
559 if (error)
560 break;
561 }
562
563 return error;
564 }
565
566 /*
567 * Lookup and open needed files.
568 *
569 * For file system internal snapshot initializes sc_mntname, sc_mount,
570 * sc_bs_vp and sc_time.
571 *
572 * Otherwise returns dev and size of the underlying block device.
573 * Initializes sc_mntname, sc_mount, sc_bdev, sc_bs_vp and sc_mount
574 */
575 static int
576 fss_create_files(struct fss_softc *sc, struct fss_set *fss,
577 off_t *bsize, struct lwp *l)
578 {
579 int error, bits, fsbsize;
580 struct timespec ts;
581 struct partinfo dpart;
582 struct vattr va;
583 /* nd -> nd2 to reduce mistakes while updating only some namei calls */
584 struct nameidata nd2;
585 struct vnode *vp;
586
587 /*
588 * Get the mounted file system.
589 */
590
591 error = namei_simple_user(fss->fss_mount,
592 NSM_FOLLOW_NOEMULROOT, &vp);
593 if (error != 0)
594 return error;
595
596 if ((vp->v_vflag & VV_ROOT) != VV_ROOT) {
597 vrele(vp);
598 return EINVAL;
599 }
600
601 sc->sc_mount = vp->v_mount;
602 memcpy(sc->sc_mntname, sc->sc_mount->mnt_stat.f_mntonname, MNAMELEN);
603
604 vrele(vp);
605
606 /*
607 * Check for file system internal snapshot.
608 */
609
610 error = namei_simple_user(fss->fss_bstore,
611 NSM_FOLLOW_NOEMULROOT, &vp);
612 if (error != 0)
613 return error;
614 error = vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
615 if (error != 0) {
616 vrele(vp);
617 return error;
618 }
619
620 if (vp->v_type == VREG && vp->v_mount == sc->sc_mount) {
621 sc->sc_flags |= FSS_PERSISTENT;
622 sc->sc_bs_vp = vp;
623
624 fsbsize = sc->sc_bs_vp->v_mount->mnt_stat.f_iosize;
625 bits = sizeof(sc->sc_bs_bshift)*NBBY;
626 for (sc->sc_bs_bshift = 1; sc->sc_bs_bshift < bits;
627 sc->sc_bs_bshift++)
628 if (FSS_FSBSIZE(sc) == fsbsize)
629 break;
630 if (sc->sc_bs_bshift >= bits) {
631 VOP_UNLOCK(sc->sc_bs_vp, 0);
632 return EINVAL;
633 }
634
635 sc->sc_bs_bmask = FSS_FSBSIZE(sc)-1;
636 sc->sc_clshift = 0;
637
638 error = VFS_SNAPSHOT(sc->sc_mount, sc->sc_bs_vp, &ts);
639 TIMESPEC_TO_TIMEVAL(&sc->sc_time, &ts);
640
641 VOP_UNLOCK(sc->sc_bs_vp, 0);
642
643 return error;
644 }
645 vput(vp);
646
647 /*
648 * Get the block device it is mounted on.
649 */
650
651 error = namei_simple_kernel(sc->sc_mount->mnt_stat.f_mntfromname,
652 NSM_FOLLOW_NOEMULROOT, &vp);
653 if (error != 0)
654 return error;
655
656 if (vp->v_type != VBLK) {
657 vrele(vp);
658 return EINVAL;
659 }
660
661 sc->sc_bdev = vp->v_rdev;
662 vrele(vp);
663
664 /*
665 * Get the block device size.
666 */
667
668 error = bdev_ioctl(sc->sc_bdev, DIOCGPART, &dpart, FREAD, l);
669 if (error)
670 return error;
671
672 *bsize = (off_t)dpart.disklab->d_secsize*dpart.part->p_size;
673
674 /*
675 * Get the backing store
676 */
677
678 NDINIT(&nd2, LOOKUP, FOLLOW, UIO_USERSPACE, fss->fss_bstore);
679 if ((error = vn_open(&nd2, FREAD|FWRITE, 0)) != 0)
680 return error;
681 VOP_UNLOCK(nd2.ni_vp, 0);
682
683 sc->sc_bs_vp = nd2.ni_vp;
684
685 if (nd2.ni_vp->v_type != VREG && nd2.ni_vp->v_type != VCHR)
686 return EINVAL;
687
688 if (sc->sc_bs_vp->v_type == VREG) {
689 error = VOP_GETATTR(sc->sc_bs_vp, &va, l->l_cred);
690 if (error != 0)
691 return error;
692 sc->sc_bs_size = va.va_size;
693 fsbsize = sc->sc_bs_vp->v_mount->mnt_stat.f_iosize;
694 if (fsbsize & (fsbsize-1)) /* No power of two */
695 return EINVAL;
696 for (sc->sc_bs_bshift = 1; sc->sc_bs_bshift < 32;
697 sc->sc_bs_bshift++)
698 if (FSS_FSBSIZE(sc) == fsbsize)
699 break;
700 if (sc->sc_bs_bshift >= 32)
701 return EINVAL;
702 sc->sc_bs_bmask = FSS_FSBSIZE(sc)-1;
703 } else {
704 sc->sc_bs_bshift = DEV_BSHIFT;
705 sc->sc_bs_bmask = FSS_FSBSIZE(sc)-1;
706 }
707
708 return 0;
709 }
710
711 /*
712 * Create a snapshot.
713 */
714 static int
715 fss_create_snapshot(struct fss_softc *sc, struct fss_set *fss, struct lwp *l)
716 {
717 int len, error;
718 u_int32_t csize;
719 off_t bsize;
720
721 bsize = 0; /* XXX gcc */
722
723 /*
724 * Open needed files.
725 */
726 if ((error = fss_create_files(sc, fss, &bsize, l)) != 0)
727 goto bad;
728
729 if (sc->sc_flags & FSS_PERSISTENT) {
730 fss_softc_alloc(sc);
731 sc->sc_flags |= FSS_ACTIVE;
732 return 0;
733 }
734
735 /*
736 * Set cluster size. Must be a power of two and
737 * a multiple of backing store block size.
738 */
739 if (fss->fss_csize <= 0)
740 csize = MAXPHYS;
741 else
742 csize = fss->fss_csize;
743 if (bsize/csize > FSS_CLUSTER_MAX)
744 csize = bsize/FSS_CLUSTER_MAX+1;
745
746 for (sc->sc_clshift = sc->sc_bs_bshift; sc->sc_clshift < 32;
747 sc->sc_clshift++)
748 if (FSS_CLSIZE(sc) >= csize)
749 break;
750 if (sc->sc_clshift >= 32) {
751 error = EINVAL;
752 goto bad;
753 }
754 sc->sc_clmask = FSS_CLSIZE(sc)-1;
755
756 /*
757 * Set number of cache slots.
758 */
759 if (FSS_CLSIZE(sc) <= 8192)
760 sc->sc_cache_size = 32;
761 else if (FSS_CLSIZE(sc) <= 65536)
762 sc->sc_cache_size = 8;
763 else
764 sc->sc_cache_size = 4;
765
766 /*
767 * Set number of clusters and size of last cluster.
768 */
769 sc->sc_clcount = FSS_BTOCL(sc, bsize-1)+1;
770 sc->sc_clresid = FSS_CLOFF(sc, bsize-1)+1;
771
772 /*
773 * Set size of indirect table.
774 */
775 len = sc->sc_clcount*sizeof(u_int32_t);
776 sc->sc_indir_size = FSS_BTOCL(sc, len)+1;
777 sc->sc_clnext = sc->sc_indir_size;
778 sc->sc_indir_cur = 0;
779
780 if ((error = fss_softc_alloc(sc)) != 0)
781 goto bad;
782
783 /*
784 * Activate the snapshot.
785 */
786
787 if ((error = vfs_suspend(sc->sc_mount, 0)) != 0)
788 goto bad;
789
790 microtime(&sc->sc_time);
791
792 if (error == 0)
793 error = fscow_establish(sc->sc_mount,
794 fss_copy_on_write, sc);
795 if (error == 0)
796 sc->sc_flags |= FSS_ACTIVE;
797
798 vfs_resume(sc->sc_mount);
799
800 if (error != 0)
801 goto bad;
802
803 aprint_debug_dev(sc->sc_dev, "%s snapshot active\n", sc->sc_mntname);
804 aprint_debug_dev(sc->sc_dev,
805 "%u clusters of %u, %u cache slots, %u indir clusters\n",
806 sc->sc_clcount, FSS_CLSIZE(sc),
807 sc->sc_cache_size, sc->sc_indir_size);
808
809 return 0;
810
811 bad:
812 fss_softc_free(sc);
813 if (sc->sc_bs_vp != NULL) {
814 if (sc->sc_flags & FSS_PERSISTENT)
815 vn_close(sc->sc_bs_vp, FREAD, l->l_cred);
816 else
817 vn_close(sc->sc_bs_vp, FREAD|FWRITE, l->l_cred);
818 }
819 sc->sc_bs_vp = NULL;
820
821 return error;
822 }
823
824 /*
825 * Delete a snapshot.
826 */
827 static int
828 fss_delete_snapshot(struct fss_softc *sc, struct lwp *l)
829 {
830
831 if ((sc->sc_flags & FSS_PERSISTENT) == 0)
832 fscow_disestablish(sc->sc_mount, fss_copy_on_write, sc);
833
834 mutex_enter(&sc->sc_slock);
835 sc->sc_flags &= ~(FSS_ACTIVE|FSS_ERROR);
836 sc->sc_mount = NULL;
837 sc->sc_bdev = NODEV;
838 mutex_exit(&sc->sc_slock);
839
840 fss_softc_free(sc);
841 if (sc->sc_flags & FSS_PERSISTENT)
842 vn_close(sc->sc_bs_vp, FREAD, l->l_cred);
843 else
844 vn_close(sc->sc_bs_vp, FREAD|FWRITE, l->l_cred);
845 sc->sc_bs_vp = NULL;
846 sc->sc_flags &= ~FSS_PERSISTENT;
847
848 return 0;
849 }
850
851 /*
852 * Read a cluster from the snapshotted block device to the cache.
853 */
854 static int
855 fss_read_cluster(struct fss_softc *sc, u_int32_t cl)
856 {
857 int error, todo, offset, len;
858 daddr_t dblk;
859 struct buf *bp, *mbp;
860 struct fss_cache *scp, *scl;
861
862 /*
863 * Get a free cache slot.
864 */
865 scl = sc->sc_cache+sc->sc_cache_size;
866
867 mutex_enter(&sc->sc_slock);
868
869 restart:
870 if (isset(sc->sc_copied, cl) || !FSS_ISVALID(sc)) {
871 mutex_exit(&sc->sc_slock);
872 return 0;
873 }
874
875 for (scp = sc->sc_cache; scp < scl; scp++)
876 if (scp->fc_cluster == cl) {
877 if (scp->fc_type == FSS_CACHE_VALID) {
878 mutex_exit(&sc->sc_slock);
879 return 0;
880 } else if (scp->fc_type == FSS_CACHE_BUSY) {
881 cv_wait(&scp->fc_state_cv, &sc->sc_slock);
882 goto restart;
883 }
884 }
885
886 for (scp = sc->sc_cache; scp < scl; scp++)
887 if (scp->fc_type == FSS_CACHE_FREE) {
888 scp->fc_type = FSS_CACHE_BUSY;
889 scp->fc_cluster = cl;
890 break;
891 }
892 if (scp >= scl) {
893 cv_wait(&sc->sc_cache_cv, &sc->sc_slock);
894 goto restart;
895 }
896
897 mutex_exit(&sc->sc_slock);
898
899 /*
900 * Start the read.
901 */
902 dblk = btodb(FSS_CLTOB(sc, cl));
903 if (cl == sc->sc_clcount-1) {
904 todo = sc->sc_clresid;
905 memset((char *)scp->fc_data + todo, 0, FSS_CLSIZE(sc) - todo);
906 } else
907 todo = FSS_CLSIZE(sc);
908 offset = 0;
909 mbp = getiobuf(NULL, true);
910 mbp->b_bufsize = todo;
911 mbp->b_data = scp->fc_data;
912 mbp->b_resid = mbp->b_bcount = todo;
913 mbp->b_flags = B_READ;
914 mbp->b_cflags = BC_BUSY;
915 mbp->b_dev = sc->sc_bdev;
916 while (todo > 0) {
917 len = todo;
918 if (len > MAXPHYS)
919 len = MAXPHYS;
920 if (btodb(FSS_CLTOB(sc, cl)) == dblk && len == todo)
921 bp = mbp;
922 else {
923 bp = getiobuf(NULL, true);
924 nestiobuf_setup(mbp, bp, offset, len);
925 }
926 bp->b_lblkno = 0;
927 bp->b_blkno = dblk;
928 bdev_strategy(bp);
929 dblk += btodb(len);
930 offset += len;
931 todo -= len;
932 }
933 error = biowait(mbp);
934 putiobuf(mbp);
935
936 mutex_enter(&sc->sc_slock);
937 scp->fc_type = (error ? FSS_CACHE_FREE : FSS_CACHE_VALID);
938 cv_broadcast(&scp->fc_state_cv);
939 if (error == 0) {
940 setbit(sc->sc_copied, scp->fc_cluster);
941 cv_signal(&sc->sc_work_cv);
942 }
943 mutex_exit(&sc->sc_slock);
944
945 return error;
946 }
947
948 /*
949 * Read/write clusters from/to backing store.
950 * For persistent snapshots must be called with cl == 0. off is the
951 * offset into the snapshot.
952 */
953 static int
954 fss_bs_io(struct fss_softc *sc, fss_io_type rw,
955 u_int32_t cl, off_t off, int len, void *data)
956 {
957 int error;
958
959 off += FSS_CLTOB(sc, cl);
960
961 vn_lock(sc->sc_bs_vp, LK_EXCLUSIVE|LK_RETRY);
962
963 error = vn_rdwr((rw == FSS_READ ? UIO_READ : UIO_WRITE), sc->sc_bs_vp,
964 data, len, off, UIO_SYSSPACE, IO_UNIT|IO_NODELOCKED,
965 sc->sc_bs_lwp->l_cred, NULL, NULL);
966 if (error == 0) {
967 mutex_enter(&sc->sc_bs_vp->v_interlock);
968 error = VOP_PUTPAGES(sc->sc_bs_vp, trunc_page(off),
969 round_page(off+len), PGO_CLEANIT|PGO_SYNCIO|PGO_FREE);
970 }
971
972 VOP_UNLOCK(sc->sc_bs_vp, 0);
973
974 return error;
975 }
976
977 /*
978 * Get a pointer to the indirect slot for this cluster.
979 */
980 static u_int32_t *
981 fss_bs_indir(struct fss_softc *sc, u_int32_t cl)
982 {
983 u_int32_t icl;
984 int ioff;
985
986 icl = cl/(FSS_CLSIZE(sc)/sizeof(u_int32_t));
987 ioff = cl%(FSS_CLSIZE(sc)/sizeof(u_int32_t));
988
989 if (sc->sc_indir_cur == icl)
990 return &sc->sc_indir_data[ioff];
991
992 if (sc->sc_indir_dirty) {
993 if (fss_bs_io(sc, FSS_WRITE, sc->sc_indir_cur, 0,
994 FSS_CLSIZE(sc), (void *)sc->sc_indir_data) != 0)
995 return NULL;
996 setbit(sc->sc_indir_valid, sc->sc_indir_cur);
997 }
998
999 sc->sc_indir_dirty = 0;
1000 sc->sc_indir_cur = icl;
1001
1002 if (isset(sc->sc_indir_valid, sc->sc_indir_cur)) {
1003 if (fss_bs_io(sc, FSS_READ, sc->sc_indir_cur, 0,
1004 FSS_CLSIZE(sc), (void *)sc->sc_indir_data) != 0)
1005 return NULL;
1006 } else
1007 memset(sc->sc_indir_data, 0, FSS_CLSIZE(sc));
1008
1009 return &sc->sc_indir_data[ioff];
1010 }
1011
1012 /*
1013 * The kernel thread (one for every active snapshot).
1014 *
1015 * After wakeup it cleans the cache and runs the I/O requests.
1016 */
1017 static void
1018 fss_bs_thread(void *arg)
1019 {
1020 bool thread_idle, is_valid;
1021 int error, i, todo, len, crotor, is_read;
1022 long off;
1023 char *addr;
1024 u_int32_t c, cl, ch, *indirp;
1025 struct buf *bp, *nbp;
1026 struct fss_softc *sc;
1027 struct fss_cache *scp, *scl;
1028
1029 sc = arg;
1030 scl = sc->sc_cache+sc->sc_cache_size;
1031 crotor = 0;
1032 thread_idle = false;
1033
1034 mutex_enter(&sc->sc_slock);
1035
1036 for (;;) {
1037 if (thread_idle)
1038 cv_wait(&sc->sc_work_cv, &sc->sc_slock);
1039 thread_idle = true;
1040 if ((sc->sc_flags & FSS_BS_THREAD) == 0) {
1041 sc->sc_bs_lwp = NULL;
1042 mutex_exit(&sc->sc_slock);
1043 kthread_exit(0);
1044 }
1045
1046 /*
1047 * Process I/O requests (persistent)
1048 */
1049
1050 if (sc->sc_flags & FSS_PERSISTENT) {
1051 if ((bp = bufq_get(sc->sc_bufq)) == NULL)
1052 continue;
1053 is_valid = FSS_ISVALID(sc);
1054 is_read = (bp->b_flags & B_READ);
1055 thread_idle = false;
1056 mutex_exit(&sc->sc_slock);
1057
1058 if (is_valid) {
1059 disk_busy(sc->sc_dkdev);
1060 error = fss_bs_io(sc, FSS_READ, 0,
1061 dbtob(bp->b_blkno), bp->b_bcount,
1062 bp->b_data);
1063 disk_unbusy(sc->sc_dkdev,
1064 (error ? 0 : bp->b_bcount), is_read);
1065 } else
1066 error = ENXIO;
1067
1068 bp->b_error = error;
1069 bp->b_resid = (error ? bp->b_bcount : 0);
1070 biodone(bp);
1071
1072 mutex_enter(&sc->sc_slock);
1073 continue;
1074 }
1075
1076 /*
1077 * Clean the cache
1078 */
1079 for (i = 0; i < sc->sc_cache_size; i++) {
1080 crotor = (crotor + 1) % sc->sc_cache_size;
1081 scp = sc->sc_cache + crotor;
1082 if (scp->fc_type != FSS_CACHE_VALID)
1083 continue;
1084 mutex_exit(&sc->sc_slock);
1085
1086 thread_idle = false;
1087 indirp = fss_bs_indir(sc, scp->fc_cluster);
1088 if (indirp != NULL) {
1089 error = fss_bs_io(sc, FSS_WRITE, sc->sc_clnext,
1090 0, FSS_CLSIZE(sc), scp->fc_data);
1091 } else
1092 error = EIO;
1093
1094 mutex_enter(&sc->sc_slock);
1095 if (error == 0) {
1096 *indirp = sc->sc_clnext++;
1097 sc->sc_indir_dirty = 1;
1098 } else
1099 fss_error(sc, "write error on backing store");
1100
1101 scp->fc_type = FSS_CACHE_FREE;
1102 cv_signal(&sc->sc_cache_cv);
1103 break;
1104 }
1105
1106 /*
1107 * Process I/O requests
1108 */
1109 if ((bp = bufq_get(sc->sc_bufq)) == NULL)
1110 continue;
1111 is_valid = FSS_ISVALID(sc);
1112 is_read = (bp->b_flags & B_READ);
1113 thread_idle = false;
1114
1115 if (!is_valid) {
1116 mutex_exit(&sc->sc_slock);
1117
1118 bp->b_error = ENXIO;
1119 bp->b_resid = bp->b_bcount;
1120 biodone(bp);
1121
1122 mutex_enter(&sc->sc_slock);
1123 continue;
1124 }
1125
1126 disk_busy(sc->sc_dkdev);
1127
1128 /*
1129 * First read from the snapshotted block device unless
1130 * this request is completely covered by backing store.
1131 */
1132
1133 cl = FSS_BTOCL(sc, dbtob(bp->b_blkno));
1134 off = FSS_CLOFF(sc, dbtob(bp->b_blkno));
1135 ch = FSS_BTOCL(sc, dbtob(bp->b_blkno)+bp->b_bcount-1);
1136 error = 0;
1137 bp->b_resid = 0;
1138 bp->b_error = 0;
1139 for (c = cl; c <= ch; c++) {
1140 if (isset(sc->sc_copied, c))
1141 continue;
1142 mutex_exit(&sc->sc_slock);
1143
1144 /* Not on backing store, read from device. */
1145 nbp = getiobuf(NULL, true);
1146 nbp->b_flags = B_READ;
1147 nbp->b_resid = nbp->b_bcount = bp->b_bcount;
1148 nbp->b_bufsize = bp->b_bcount;
1149 nbp->b_data = bp->b_data;
1150 nbp->b_blkno = bp->b_blkno;
1151 nbp->b_lblkno = 0;
1152 nbp->b_dev = sc->sc_bdev;
1153 SET(nbp->b_cflags, BC_BUSY); /* mark buffer busy */
1154
1155 bdev_strategy(nbp);
1156
1157 error = biowait(nbp);
1158 if (error != 0) {
1159 bp->b_resid = bp->b_bcount;
1160 bp->b_error = nbp->b_error;
1161 disk_unbusy(sc->sc_dkdev, 0, is_read);
1162 biodone(bp);
1163 }
1164 putiobuf(nbp);
1165
1166 mutex_enter(&sc->sc_slock);
1167 break;
1168 }
1169 if (error)
1170 continue;
1171
1172 /*
1173 * Replace those parts that have been saved to backing store.
1174 */
1175
1176 addr = bp->b_data;
1177 todo = bp->b_bcount;
1178 for (c = cl; c <= ch; c++, off = 0, todo -= len, addr += len) {
1179 len = FSS_CLSIZE(sc)-off;
1180 if (len > todo)
1181 len = todo;
1182 if (isclr(sc->sc_copied, c))
1183 continue;
1184 mutex_exit(&sc->sc_slock);
1185
1186 indirp = fss_bs_indir(sc, c);
1187 if (indirp == NULL || *indirp == 0) {
1188 /*
1189 * Not on backing store. Either in cache
1190 * or hole in the snapshotted block device.
1191 */
1192
1193 mutex_enter(&sc->sc_slock);
1194 for (scp = sc->sc_cache; scp < scl; scp++)
1195 if (scp->fc_type == FSS_CACHE_VALID &&
1196 scp->fc_cluster == c)
1197 break;
1198 if (scp < scl)
1199 memcpy(addr, (char *)scp->fc_data+off,
1200 len);
1201 else
1202 memset(addr, 0, len);
1203 continue;
1204 }
1205
1206 /*
1207 * Read from backing store.
1208 */
1209 error =
1210 fss_bs_io(sc, FSS_READ, *indirp, off, len, addr);
1211
1212 mutex_enter(&sc->sc_slock);
1213 if (error) {
1214 bp->b_resid = bp->b_bcount;
1215 bp->b_error = error;
1216 break;
1217 }
1218 }
1219 mutex_exit(&sc->sc_slock);
1220
1221 disk_unbusy(sc->sc_dkdev, (error ? 0 : bp->b_bcount), is_read);
1222 biodone(bp);
1223
1224 mutex_enter(&sc->sc_slock);
1225 }
1226 }
1227
1228 #ifdef _MODULE
1229
1230 #include <sys/module.h>
1231
1232 MODULE(MODULE_CLASS_DRIVER, fss, NULL);
1233 CFDRIVER_DECL(fss, DV_DISK, NULL);
1234
1235 static int
1236 fss_modcmd(modcmd_t cmd, void *arg)
1237 {
1238 int bmajor = -1, cmajor = -1, error = 0;
1239
1240 switch (cmd) {
1241 case MODULE_CMD_INIT:
1242 mutex_init(&fss_device_lock, MUTEX_DEFAULT, IPL_NONE);
1243 error = config_cfdriver_attach(&fss_cd);
1244 if (error) {
1245 mutex_destroy(&fss_device_lock);
1246 break;
1247 }
1248 error = config_cfattach_attach(fss_cd.cd_name, &fss_ca);
1249 if (error) {
1250 config_cfdriver_detach(&fss_cd);
1251 mutex_destroy(&fss_device_lock);
1252 break;
1253 }
1254 error = devsw_attach(fss_cd.cd_name,
1255 &fss_bdevsw, &bmajor, &fss_cdevsw, &cmajor);
1256 if (error) {
1257 config_cfattach_detach(fss_cd.cd_name, &fss_ca);
1258 config_cfdriver_detach(&fss_cd);
1259 mutex_destroy(&fss_device_lock);
1260 break;
1261 }
1262 break;
1263
1264 case MODULE_CMD_FINI:
1265 error = config_cfattach_detach(fss_cd.cd_name, &fss_ca);
1266 if (error)
1267 break;
1268 config_cfdriver_detach(&fss_cd);
1269 devsw_detach(&fss_bdevsw, &fss_cdevsw);
1270 mutex_destroy(&fss_device_lock);
1271 break;
1272
1273 default:
1274 error = ENOTTY;
1275 break;
1276 }
1277
1278 return error;
1279 }
1280
1281 #endif /* _MODULE */
NetBSD on the FriendlyARM MINI2440