1 /* $NetBSD: fss.c,v 1.65 2009/10/17 10:29:29 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 1.65 2009/10/17 10:29:29 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 */ 1282