fss.c revision 1.70
1 /* $NetBSD: fss.c,v 1.70 2010/06/24 13:03:08 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 1.70 2010/06/24 13:03:08 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 mutex_exit(&fss_device_lock); 201 return ENOMEM; 202 } 203 } 204 205 mutex_enter(&sc->sc_slock); 206 207 sc->sc_flags |= mflag; 208 209 mutex_exit(&sc->sc_slock); 210 mutex_exit(&fss_device_lock); 211 212 return 0; 213 } 214 215 int 216 fss_close(dev_t dev, int flags, int mode, struct lwp *l) 217 { 218 int mflag, error; 219 cfdata_t cf; 220 struct fss_softc *sc = device_lookup_private(&fss_cd, minor(dev)); 221 222 mflag = (mode == S_IFCHR ? FSS_CDEV_OPEN : FSS_BDEV_OPEN); 223 error = 0; 224 225 restart: 226 mutex_enter(&sc->sc_slock); 227 if ((sc->sc_flags & (FSS_CDEV_OPEN|FSS_BDEV_OPEN)) != mflag) { 228 sc->sc_flags &= ~mflag; 229 mutex_exit(&sc->sc_slock); 230 return 0; 231 } 232 if ((sc->sc_flags & FSS_ACTIVE) != 0 && 233 (sc->sc_uflags & FSS_UNCONFIG_ON_CLOSE) != 0) { 234 sc->sc_uflags &= ~FSS_UNCONFIG_ON_CLOSE; 235 mutex_exit(&sc->sc_slock); 236 error = fss_ioctl(dev, FSSIOCCLR, NULL, FWRITE, l); 237 goto restart; 238 } 239 if ((sc->sc_flags & FSS_ACTIVE) != 0) { 240 mutex_exit(&sc->sc_slock); 241 return error; 242 } 243 if (! mutex_tryenter(&fss_device_lock)) { 244 mutex_exit(&sc->sc_slock); 245 goto restart; 246 } 247 248 KASSERT((sc->sc_flags & FSS_ACTIVE) == 0); 249 KASSERT((sc->sc_flags & (FSS_CDEV_OPEN|FSS_BDEV_OPEN)) == mflag); 250 mutex_exit(&sc->sc_slock); 251 cf = device_cfdata(sc->sc_dev); 252 error = config_detach(sc->sc_dev, DETACH_QUIET); 253 if (! error) 254 free(cf, M_DEVBUF); 255 mutex_exit(&fss_device_lock); 256 257 return error; 258 } 259 260 void 261 fss_strategy(struct buf *bp) 262 { 263 const bool write = ((bp->b_flags & B_READ) != B_READ); 264 struct fss_softc *sc = device_lookup_private(&fss_cd, minor(bp->b_dev)); 265 266 mutex_enter(&sc->sc_slock); 267 268 if (write || !FSS_ISVALID(sc)) { 269 270 mutex_exit(&sc->sc_slock); 271 272 bp->b_error = (write ? EROFS : ENXIO); 273 bp->b_resid = bp->b_bcount; 274 biodone(bp); 275 return; 276 } 277 278 bp->b_rawblkno = bp->b_blkno; 279 bufq_put(sc->sc_bufq, bp); 280 cv_signal(&sc->sc_work_cv); 281 282 mutex_exit(&sc->sc_slock); 283 } 284 285 int 286 fss_read(dev_t dev, struct uio *uio, int flags) 287 { 288 return physio(fss_strategy, NULL, dev, B_READ, minphys, uio); 289 } 290 291 int 292 fss_write(dev_t dev, struct uio *uio, int flags) 293 { 294 return physio(fss_strategy, NULL, dev, B_WRITE, minphys, uio); 295 } 296 297 int 298 fss_ioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l) 299 { 300 int error; 301 struct fss_softc *sc = device_lookup_private(&fss_cd, minor(dev)); 302 struct fss_set *fss = (struct fss_set *)data; 303 struct fss_get *fsg = (struct fss_get *)data; 304 305 switch (cmd) { 306 case FSSIOCSET: 307 mutex_enter(&sc->sc_lock); 308 if ((flag & FWRITE) == 0) 309 error = EPERM; 310 else if ((sc->sc_flags & FSS_ACTIVE) != 0) 311 error = EBUSY; 312 else 313 error = fss_create_snapshot(sc, fss, l); 314 mutex_exit(&sc->sc_lock); 315 break; 316 317 case FSSIOCCLR: 318 mutex_enter(&sc->sc_lock); 319 if ((flag & FWRITE) == 0) 320 error = EPERM; 321 else if ((sc->sc_flags & FSS_ACTIVE) == 0) 322 error = ENXIO; 323 else 324 error = fss_delete_snapshot(sc, l); 325 mutex_exit(&sc->sc_lock); 326 break; 327 328 case FSSIOCGET: 329 mutex_enter(&sc->sc_lock); 330 switch (sc->sc_flags & (FSS_PERSISTENT | FSS_ACTIVE)) { 331 case FSS_ACTIVE: 332 memcpy(fsg->fsg_mount, sc->sc_mntname, MNAMELEN); 333 fsg->fsg_csize = FSS_CLSIZE(sc); 334 fsg->fsg_time = sc->sc_time; 335 fsg->fsg_mount_size = sc->sc_clcount; 336 fsg->fsg_bs_size = sc->sc_clnext; 337 error = 0; 338 break; 339 case FSS_PERSISTENT | FSS_ACTIVE: 340 memcpy(fsg->fsg_mount, sc->sc_mntname, MNAMELEN); 341 fsg->fsg_csize = 0; 342 fsg->fsg_time = sc->sc_time; 343 fsg->fsg_mount_size = 0; 344 fsg->fsg_bs_size = 0; 345 error = 0; 346 break; 347 default: 348 error = ENXIO; 349 break; 350 } 351 mutex_exit(&sc->sc_lock); 352 break; 353 354 case FSSIOFSET: 355 mutex_enter(&sc->sc_slock); 356 sc->sc_uflags = *(int *)data; 357 mutex_exit(&sc->sc_slock); 358 error = 0; 359 break; 360 361 case FSSIOFGET: 362 mutex_enter(&sc->sc_slock); 363 *(int *)data = sc->sc_uflags; 364 mutex_exit(&sc->sc_slock); 365 error = 0; 366 break; 367 368 default: 369 error = EINVAL; 370 break; 371 } 372 373 return error; 374 } 375 376 int 377 fss_size(dev_t dev) 378 { 379 return -1; 380 } 381 382 int 383 fss_dump(dev_t dev, daddr_t blkno, void *va, 384 size_t size) 385 { 386 return EROFS; 387 } 388 389 /* 390 * An error occurred reading or writing the snapshot or backing store. 391 * If it is the first error log to console. 392 * The caller holds the mutex. 393 */ 394 static inline void 395 fss_error(struct fss_softc *sc, const char *msg) 396 { 397 398 if ((sc->sc_flags & (FSS_ACTIVE|FSS_ERROR)) == FSS_ACTIVE) 399 aprint_error_dev(sc->sc_dev, "snapshot invalid: %s\n", msg); 400 if ((sc->sc_flags & FSS_ACTIVE) == FSS_ACTIVE) 401 sc->sc_flags |= FSS_ERROR; 402 } 403 404 /* 405 * Allocate the variable sized parts of the softc and 406 * fork the kernel thread. 407 * 408 * The fields sc_clcount, sc_clshift, sc_cache_size and sc_indir_size 409 * must be initialized. 410 */ 411 static int 412 fss_softc_alloc(struct fss_softc *sc) 413 { 414 int i, error; 415 416 if ((sc->sc_flags & FSS_PERSISTENT) == 0) { 417 sc->sc_copied = 418 kmem_zalloc(howmany(sc->sc_clcount, NBBY), KM_SLEEP); 419 if (sc->sc_copied == NULL) 420 return(ENOMEM); 421 422 sc->sc_cache = kmem_alloc(sc->sc_cache_size * 423 sizeof(struct fss_cache), KM_SLEEP); 424 if (sc->sc_cache == NULL) 425 return(ENOMEM); 426 427 for (i = 0; i < sc->sc_cache_size; i++) { 428 sc->sc_cache[i].fc_type = FSS_CACHE_FREE; 429 sc->sc_cache[i].fc_data = 430 kmem_alloc(FSS_CLSIZE(sc), KM_SLEEP); 431 if (sc->sc_cache[i].fc_data == NULL) 432 return(ENOMEM); 433 cv_init(&sc->sc_cache[i].fc_state_cv, "cowwait1"); 434 } 435 436 sc->sc_indir_valid = 437 kmem_zalloc(howmany(sc->sc_indir_size, NBBY), KM_SLEEP); 438 if (sc->sc_indir_valid == NULL) 439 return(ENOMEM); 440 441 sc->sc_indir_data = kmem_zalloc(FSS_CLSIZE(sc), KM_SLEEP); 442 if (sc->sc_indir_data == NULL) 443 return(ENOMEM); 444 } else { 445 sc->sc_copied = NULL; 446 sc->sc_cache = NULL; 447 sc->sc_indir_valid = NULL; 448 sc->sc_indir_data = NULL; 449 } 450 451 sc->sc_flags |= FSS_BS_THREAD; 452 if ((error = kthread_create(PRI_BIO, 0, NULL, fss_bs_thread, sc, 453 &sc->sc_bs_lwp, device_xname(sc->sc_dev))) != 0) { 454 sc->sc_flags &= ~FSS_BS_THREAD; 455 return error; 456 } 457 458 disk_attach(sc->sc_dkdev); 459 460 return 0; 461 } 462 463 /* 464 * Free the variable sized parts of the softc. 465 */ 466 static void 467 fss_softc_free(struct fss_softc *sc) 468 { 469 int i; 470 471 if ((sc->sc_flags & FSS_BS_THREAD) != 0) { 472 mutex_enter(&sc->sc_slock); 473 sc->sc_flags &= ~FSS_BS_THREAD; 474 cv_signal(&sc->sc_work_cv); 475 while (sc->sc_bs_lwp != NULL) 476 kpause("fssdetach", false, 1, &sc->sc_slock); 477 mutex_exit(&sc->sc_slock); 478 479 disk_detach(sc->sc_dkdev); 480 } 481 482 if (sc->sc_copied != NULL) 483 kmem_free(sc->sc_copied, howmany(sc->sc_clcount, NBBY)); 484 sc->sc_copied = NULL; 485 486 if (sc->sc_cache != NULL) { 487 for (i = 0; i < sc->sc_cache_size; i++) 488 if (sc->sc_cache[i].fc_data != NULL) { 489 cv_destroy(&sc->sc_cache[i].fc_state_cv); 490 kmem_free(sc->sc_cache[i].fc_data, 491 FSS_CLSIZE(sc)); 492 } 493 kmem_free(sc->sc_cache, 494 sc->sc_cache_size*sizeof(struct fss_cache)); 495 } 496 sc->sc_cache = NULL; 497 498 if (sc->sc_indir_valid != NULL) 499 kmem_free(sc->sc_indir_valid, howmany(sc->sc_indir_size, NBBY)); 500 sc->sc_indir_valid = NULL; 501 502 if (sc->sc_indir_data != NULL) 503 kmem_free(sc->sc_indir_data, FSS_CLSIZE(sc)); 504 sc->sc_indir_data = NULL; 505 } 506 507 /* 508 * Set all active snapshots on this file system into ERROR state. 509 */ 510 static void 511 fss_unmount_hook(struct mount *mp) 512 { 513 int i; 514 struct fss_softc *sc; 515 516 mutex_enter(&fss_device_lock); 517 for (i = 0; i < fss_cd.cd_ndevs; i++) { 518 if ((sc = device_lookup_private(&fss_cd, i)) == NULL) 519 continue; 520 mutex_enter(&sc->sc_slock); 521 if ((sc->sc_flags & FSS_ACTIVE) != 0 && 522 sc->sc_mount == mp) 523 fss_error(sc, "forced unmount"); 524 mutex_exit(&sc->sc_slock); 525 } 526 mutex_exit(&fss_device_lock); 527 } 528 529 /* 530 * A buffer is written to the snapshotted block device. Copy to 531 * backing store if needed. 532 */ 533 static int 534 fss_copy_on_write(void *v, struct buf *bp, bool data_valid) 535 { 536 int error; 537 u_int32_t cl, ch, c; 538 struct fss_softc *sc = v; 539 540 mutex_enter(&sc->sc_slock); 541 if (!FSS_ISVALID(sc)) { 542 mutex_exit(&sc->sc_slock); 543 return 0; 544 } 545 546 cl = FSS_BTOCL(sc, dbtob(bp->b_blkno)); 547 ch = FSS_BTOCL(sc, dbtob(bp->b_blkno)+bp->b_bcount-1); 548 error = 0; 549 if (curlwp == uvm.pagedaemon_lwp) { 550 for (c = cl; c <= ch; c++) 551 if (isclr(sc->sc_copied, c)) { 552 error = ENOMEM; 553 break; 554 } 555 } 556 mutex_exit(&sc->sc_slock); 557 558 if (error == 0) 559 for (c = cl; c <= ch; c++) { 560 error = fss_read_cluster(sc, c); 561 if (error) 562 break; 563 } 564 565 return error; 566 } 567 568 /* 569 * Lookup and open needed files. 570 * 571 * For file system internal snapshot initializes sc_mntname, sc_mount, 572 * sc_bs_vp and sc_time. 573 * 574 * Otherwise returns dev and size of the underlying block device. 575 * Initializes sc_mntname, sc_mount, sc_bdev, sc_bs_vp and sc_mount 576 */ 577 static int 578 fss_create_files(struct fss_softc *sc, struct fss_set *fss, 579 off_t *bsize, struct lwp *l) 580 { 581 int error, bits, fsbsize; 582 struct timespec ts; 583 struct partinfo dpart; 584 /* nd -> nd2 to reduce mistakes while updating only some namei calls */ 585 struct nameidata nd2; 586 struct vnode *vp; 587 588 /* 589 * Get the mounted file system. 590 */ 591 592 error = namei_simple_user(fss->fss_mount, 593 NSM_FOLLOW_NOEMULROOT, &vp); 594 if (error != 0) 595 return error; 596 597 if ((vp->v_vflag & VV_ROOT) != VV_ROOT) { 598 vrele(vp); 599 return EINVAL; 600 } 601 602 sc->sc_mount = vp->v_mount; 603 memcpy(sc->sc_mntname, sc->sc_mount->mnt_stat.f_mntonname, MNAMELEN); 604 605 vrele(vp); 606 607 /* 608 * Check for file system internal snapshot. 609 */ 610 611 error = namei_simple_user(fss->fss_bstore, 612 NSM_FOLLOW_NOEMULROOT, &vp); 613 if (error != 0) 614 return error; 615 error = vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 616 if (error != 0) { 617 vrele(vp); 618 return error; 619 } 620 621 if (vp->v_type == VREG && vp->v_mount == sc->sc_mount) { 622 sc->sc_flags |= FSS_PERSISTENT; 623 sc->sc_bs_vp = vp; 624 625 fsbsize = sc->sc_bs_vp->v_mount->mnt_stat.f_iosize; 626 bits = sizeof(sc->sc_bs_bshift)*NBBY; 627 for (sc->sc_bs_bshift = 1; sc->sc_bs_bshift < bits; 628 sc->sc_bs_bshift++) 629 if (FSS_FSBSIZE(sc) == fsbsize) 630 break; 631 if (sc->sc_bs_bshift >= bits) { 632 VOP_UNLOCK(sc->sc_bs_vp); 633 return EINVAL; 634 } 635 636 sc->sc_bs_bmask = FSS_FSBSIZE(sc)-1; 637 sc->sc_clshift = 0; 638 639 error = VFS_SNAPSHOT(sc->sc_mount, sc->sc_bs_vp, &ts); 640 TIMESPEC_TO_TIMEVAL(&sc->sc_time, &ts); 641 642 VOP_UNLOCK(sc->sc_bs_vp); 643 644 return error; 645 } 646 vput(vp); 647 648 /* 649 * Get the block device it is mounted on. 650 */ 651 652 error = namei_simple_kernel(sc->sc_mount->mnt_stat.f_mntfromname, 653 NSM_FOLLOW_NOEMULROOT, &vp); 654 if (error != 0) 655 return error; 656 657 if (vp->v_type != VBLK) { 658 vrele(vp); 659 return EINVAL; 660 } 661 662 sc->sc_bdev = vp->v_rdev; 663 vrele(vp); 664 665 /* 666 * Get the block device size. 667 */ 668 669 error = bdev_ioctl(sc->sc_bdev, DIOCGPART, &dpart, FREAD, l); 670 if (error) 671 return error; 672 673 *bsize = (off_t)dpart.disklab->d_secsize*dpart.part->p_size; 674 675 /* 676 * Get the backing store 677 */ 678 679 NDINIT(&nd2, LOOKUP, FOLLOW, UIO_USERSPACE, fss->fss_bstore); 680 if ((error = vn_open(&nd2, FREAD|FWRITE, 0)) != 0) 681 return error; 682 VOP_UNLOCK(nd2.ni_vp); 683 684 sc->sc_bs_vp = nd2.ni_vp; 685 686 if (nd2.ni_vp->v_type != VREG && nd2.ni_vp->v_type != VCHR) 687 return EINVAL; 688 689 if (sc->sc_bs_vp->v_type == VREG) { 690 fsbsize = sc->sc_bs_vp->v_mount->mnt_stat.f_iosize; 691 if (fsbsize & (fsbsize-1)) /* No power of two */ 692 return EINVAL; 693 for (sc->sc_bs_bshift = 1; sc->sc_bs_bshift < 32; 694 sc->sc_bs_bshift++) 695 if (FSS_FSBSIZE(sc) == fsbsize) 696 break; 697 if (sc->sc_bs_bshift >= 32) 698 return EINVAL; 699 sc->sc_bs_bmask = FSS_FSBSIZE(sc)-1; 700 } else { 701 sc->sc_bs_bshift = DEV_BSHIFT; 702 sc->sc_bs_bmask = FSS_FSBSIZE(sc)-1; 703 } 704 705 return 0; 706 } 707 708 /* 709 * Create a snapshot. 710 */ 711 static int 712 fss_create_snapshot(struct fss_softc *sc, struct fss_set *fss, struct lwp *l) 713 { 714 int len, error; 715 u_int32_t csize; 716 off_t bsize; 717 718 bsize = 0; /* XXX gcc */ 719 720 /* 721 * Open needed files. 722 */ 723 if ((error = fss_create_files(sc, fss, &bsize, l)) != 0) 724 goto bad; 725 726 if (sc->sc_flags & FSS_PERSISTENT) { 727 fss_softc_alloc(sc); 728 sc->sc_flags |= FSS_ACTIVE; 729 return 0; 730 } 731 732 /* 733 * Set cluster size. Must be a power of two and 734 * a multiple of backing store block size. 735 */ 736 if (fss->fss_csize <= 0) 737 csize = MAXPHYS; 738 else 739 csize = fss->fss_csize; 740 if (bsize/csize > FSS_CLUSTER_MAX) 741 csize = bsize/FSS_CLUSTER_MAX+1; 742 743 for (sc->sc_clshift = sc->sc_bs_bshift; sc->sc_clshift < 32; 744 sc->sc_clshift++) 745 if (FSS_CLSIZE(sc) >= csize) 746 break; 747 if (sc->sc_clshift >= 32) { 748 error = EINVAL; 749 goto bad; 750 } 751 sc->sc_clmask = FSS_CLSIZE(sc)-1; 752 753 /* 754 * Set number of cache slots. 755 */ 756 if (FSS_CLSIZE(sc) <= 8192) 757 sc->sc_cache_size = 32; 758 else if (FSS_CLSIZE(sc) <= 65536) 759 sc->sc_cache_size = 8; 760 else 761 sc->sc_cache_size = 4; 762 763 /* 764 * Set number of clusters and size of last cluster. 765 */ 766 sc->sc_clcount = FSS_BTOCL(sc, bsize-1)+1; 767 sc->sc_clresid = FSS_CLOFF(sc, bsize-1)+1; 768 769 /* 770 * Set size of indirect table. 771 */ 772 len = sc->sc_clcount*sizeof(u_int32_t); 773 sc->sc_indir_size = FSS_BTOCL(sc, len)+1; 774 sc->sc_clnext = sc->sc_indir_size; 775 sc->sc_indir_cur = 0; 776 777 if ((error = fss_softc_alloc(sc)) != 0) 778 goto bad; 779 780 /* 781 * Activate the snapshot. 782 */ 783 784 if ((error = vfs_suspend(sc->sc_mount, 0)) != 0) 785 goto bad; 786 787 microtime(&sc->sc_time); 788 789 if (error == 0) 790 error = fscow_establish(sc->sc_mount, 791 fss_copy_on_write, sc); 792 if (error == 0) 793 sc->sc_flags |= FSS_ACTIVE; 794 795 vfs_resume(sc->sc_mount); 796 797 if (error != 0) 798 goto bad; 799 800 aprint_debug_dev(sc->sc_dev, "%s snapshot active\n", sc->sc_mntname); 801 aprint_debug_dev(sc->sc_dev, 802 "%u clusters of %u, %u cache slots, %u indir clusters\n", 803 sc->sc_clcount, FSS_CLSIZE(sc), 804 sc->sc_cache_size, sc->sc_indir_size); 805 806 return 0; 807 808 bad: 809 fss_softc_free(sc); 810 if (sc->sc_bs_vp != NULL) { 811 if (sc->sc_flags & FSS_PERSISTENT) 812 vn_close(sc->sc_bs_vp, FREAD, l->l_cred); 813 else 814 vn_close(sc->sc_bs_vp, FREAD|FWRITE, l->l_cred); 815 } 816 sc->sc_bs_vp = NULL; 817 818 return error; 819 } 820 821 /* 822 * Delete a snapshot. 823 */ 824 static int 825 fss_delete_snapshot(struct fss_softc *sc, struct lwp *l) 826 { 827 828 if ((sc->sc_flags & FSS_PERSISTENT) == 0) 829 fscow_disestablish(sc->sc_mount, fss_copy_on_write, sc); 830 831 mutex_enter(&sc->sc_slock); 832 sc->sc_flags &= ~(FSS_ACTIVE|FSS_ERROR); 833 sc->sc_mount = NULL; 834 sc->sc_bdev = NODEV; 835 mutex_exit(&sc->sc_slock); 836 837 fss_softc_free(sc); 838 if (sc->sc_flags & FSS_PERSISTENT) 839 vn_close(sc->sc_bs_vp, FREAD, l->l_cred); 840 else 841 vn_close(sc->sc_bs_vp, FREAD|FWRITE, l->l_cred); 842 sc->sc_bs_vp = NULL; 843 sc->sc_flags &= ~FSS_PERSISTENT; 844 845 return 0; 846 } 847 848 /* 849 * Read a cluster from the snapshotted block device to the cache. 850 */ 851 static int 852 fss_read_cluster(struct fss_softc *sc, u_int32_t cl) 853 { 854 int error, todo, offset, len; 855 daddr_t dblk; 856 struct buf *bp, *mbp; 857 struct fss_cache *scp, *scl; 858 859 /* 860 * Get a free cache slot. 861 */ 862 scl = sc->sc_cache+sc->sc_cache_size; 863 864 mutex_enter(&sc->sc_slock); 865 866 restart: 867 if (isset(sc->sc_copied, cl) || !FSS_ISVALID(sc)) { 868 mutex_exit(&sc->sc_slock); 869 return 0; 870 } 871 872 for (scp = sc->sc_cache; scp < scl; scp++) 873 if (scp->fc_cluster == cl) { 874 if (scp->fc_type == FSS_CACHE_VALID) { 875 mutex_exit(&sc->sc_slock); 876 return 0; 877 } else if (scp->fc_type == FSS_CACHE_BUSY) { 878 cv_wait(&scp->fc_state_cv, &sc->sc_slock); 879 goto restart; 880 } 881 } 882 883 for (scp = sc->sc_cache; scp < scl; scp++) 884 if (scp->fc_type == FSS_CACHE_FREE) { 885 scp->fc_type = FSS_CACHE_BUSY; 886 scp->fc_cluster = cl; 887 break; 888 } 889 if (scp >= scl) { 890 cv_wait(&sc->sc_cache_cv, &sc->sc_slock); 891 goto restart; 892 } 893 894 mutex_exit(&sc->sc_slock); 895 896 /* 897 * Start the read. 898 */ 899 dblk = btodb(FSS_CLTOB(sc, cl)); 900 if (cl == sc->sc_clcount-1) { 901 todo = sc->sc_clresid; 902 memset((char *)scp->fc_data + todo, 0, FSS_CLSIZE(sc) - todo); 903 } else 904 todo = FSS_CLSIZE(sc); 905 offset = 0; 906 mbp = getiobuf(NULL, true); 907 mbp->b_bufsize = todo; 908 mbp->b_data = scp->fc_data; 909 mbp->b_resid = mbp->b_bcount = todo; 910 mbp->b_flags = B_READ; 911 mbp->b_cflags = BC_BUSY; 912 mbp->b_dev = sc->sc_bdev; 913 while (todo > 0) { 914 len = todo; 915 if (len > MAXPHYS) 916 len = MAXPHYS; 917 if (btodb(FSS_CLTOB(sc, cl)) == dblk && len == todo) 918 bp = mbp; 919 else { 920 bp = getiobuf(NULL, true); 921 nestiobuf_setup(mbp, bp, offset, len); 922 } 923 bp->b_lblkno = 0; 924 bp->b_blkno = dblk; 925 bdev_strategy(bp); 926 dblk += btodb(len); 927 offset += len; 928 todo -= len; 929 } 930 error = biowait(mbp); 931 putiobuf(mbp); 932 933 mutex_enter(&sc->sc_slock); 934 scp->fc_type = (error ? FSS_CACHE_FREE : FSS_CACHE_VALID); 935 cv_broadcast(&scp->fc_state_cv); 936 if (error == 0) { 937 setbit(sc->sc_copied, scp->fc_cluster); 938 cv_signal(&sc->sc_work_cv); 939 } 940 mutex_exit(&sc->sc_slock); 941 942 return error; 943 } 944 945 /* 946 * Read/write clusters from/to backing store. 947 * For persistent snapshots must be called with cl == 0. off is the 948 * offset into the snapshot. 949 */ 950 static int 951 fss_bs_io(struct fss_softc *sc, fss_io_type rw, 952 u_int32_t cl, off_t off, int len, void *data) 953 { 954 int error; 955 956 off += FSS_CLTOB(sc, cl); 957 958 vn_lock(sc->sc_bs_vp, LK_EXCLUSIVE|LK_RETRY); 959 960 error = vn_rdwr((rw == FSS_READ ? UIO_READ : UIO_WRITE), sc->sc_bs_vp, 961 data, len, off, UIO_SYSSPACE, IO_UNIT|IO_NODELOCKED, 962 sc->sc_bs_lwp->l_cred, NULL, NULL); 963 if (error == 0) { 964 mutex_enter(&sc->sc_bs_vp->v_interlock); 965 error = VOP_PUTPAGES(sc->sc_bs_vp, trunc_page(off), 966 round_page(off+len), PGO_CLEANIT|PGO_SYNCIO|PGO_FREE); 967 } 968 969 VOP_UNLOCK(sc->sc_bs_vp); 970 971 return error; 972 } 973 974 /* 975 * Get a pointer to the indirect slot for this cluster. 976 */ 977 static u_int32_t * 978 fss_bs_indir(struct fss_softc *sc, u_int32_t cl) 979 { 980 u_int32_t icl; 981 int ioff; 982 983 icl = cl/(FSS_CLSIZE(sc)/sizeof(u_int32_t)); 984 ioff = cl%(FSS_CLSIZE(sc)/sizeof(u_int32_t)); 985 986 if (sc->sc_indir_cur == icl) 987 return &sc->sc_indir_data[ioff]; 988 989 if (sc->sc_indir_dirty) { 990 if (fss_bs_io(sc, FSS_WRITE, sc->sc_indir_cur, 0, 991 FSS_CLSIZE(sc), (void *)sc->sc_indir_data) != 0) 992 return NULL; 993 setbit(sc->sc_indir_valid, sc->sc_indir_cur); 994 } 995 996 sc->sc_indir_dirty = 0; 997 sc->sc_indir_cur = icl; 998 999 if (isset(sc->sc_indir_valid, sc->sc_indir_cur)) { 1000 if (fss_bs_io(sc, FSS_READ, sc->sc_indir_cur, 0, 1001 FSS_CLSIZE(sc), (void *)sc->sc_indir_data) != 0) 1002 return NULL; 1003 } else 1004 memset(sc->sc_indir_data, 0, FSS_CLSIZE(sc)); 1005 1006 return &sc->sc_indir_data[ioff]; 1007 } 1008 1009 /* 1010 * The kernel thread (one for every active snapshot). 1011 * 1012 * After wakeup it cleans the cache and runs the I/O requests. 1013 */ 1014 static void 1015 fss_bs_thread(void *arg) 1016 { 1017 bool thread_idle, is_valid; 1018 int error, i, todo, len, crotor, is_read; 1019 long off; 1020 char *addr; 1021 u_int32_t c, cl, ch, *indirp; 1022 struct buf *bp, *nbp; 1023 struct fss_softc *sc; 1024 struct fss_cache *scp, *scl; 1025 1026 sc = arg; 1027 scl = sc->sc_cache+sc->sc_cache_size; 1028 crotor = 0; 1029 thread_idle = false; 1030 1031 mutex_enter(&sc->sc_slock); 1032 1033 for (;;) { 1034 if (thread_idle) 1035 cv_wait(&sc->sc_work_cv, &sc->sc_slock); 1036 thread_idle = true; 1037 if ((sc->sc_flags & FSS_BS_THREAD) == 0) { 1038 sc->sc_bs_lwp = NULL; 1039 mutex_exit(&sc->sc_slock); 1040 kthread_exit(0); 1041 } 1042 1043 /* 1044 * Process I/O requests (persistent) 1045 */ 1046 1047 if (sc->sc_flags & FSS_PERSISTENT) { 1048 if ((bp = bufq_get(sc->sc_bufq)) == NULL) 1049 continue; 1050 is_valid = FSS_ISVALID(sc); 1051 is_read = (bp->b_flags & B_READ); 1052 thread_idle = false; 1053 mutex_exit(&sc->sc_slock); 1054 1055 if (is_valid) { 1056 disk_busy(sc->sc_dkdev); 1057 error = fss_bs_io(sc, FSS_READ, 0, 1058 dbtob(bp->b_blkno), bp->b_bcount, 1059 bp->b_data); 1060 disk_unbusy(sc->sc_dkdev, 1061 (error ? 0 : bp->b_bcount), is_read); 1062 } else 1063 error = ENXIO; 1064 1065 bp->b_error = error; 1066 bp->b_resid = (error ? bp->b_bcount : 0); 1067 biodone(bp); 1068 1069 mutex_enter(&sc->sc_slock); 1070 continue; 1071 } 1072 1073 /* 1074 * Clean the cache 1075 */ 1076 for (i = 0; i < sc->sc_cache_size; i++) { 1077 crotor = (crotor + 1) % sc->sc_cache_size; 1078 scp = sc->sc_cache + crotor; 1079 if (scp->fc_type != FSS_CACHE_VALID) 1080 continue; 1081 mutex_exit(&sc->sc_slock); 1082 1083 thread_idle = false; 1084 indirp = fss_bs_indir(sc, scp->fc_cluster); 1085 if (indirp != NULL) { 1086 error = fss_bs_io(sc, FSS_WRITE, sc->sc_clnext, 1087 0, FSS_CLSIZE(sc), scp->fc_data); 1088 } else 1089 error = EIO; 1090 1091 mutex_enter(&sc->sc_slock); 1092 if (error == 0) { 1093 *indirp = sc->sc_clnext++; 1094 sc->sc_indir_dirty = 1; 1095 } else 1096 fss_error(sc, "write error on backing store"); 1097 1098 scp->fc_type = FSS_CACHE_FREE; 1099 cv_signal(&sc->sc_cache_cv); 1100 break; 1101 } 1102 1103 /* 1104 * Process I/O requests 1105 */ 1106 if ((bp = bufq_get(sc->sc_bufq)) == NULL) 1107 continue; 1108 is_valid = FSS_ISVALID(sc); 1109 is_read = (bp->b_flags & B_READ); 1110 thread_idle = false; 1111 1112 if (!is_valid) { 1113 mutex_exit(&sc->sc_slock); 1114 1115 bp->b_error = ENXIO; 1116 bp->b_resid = bp->b_bcount; 1117 biodone(bp); 1118 1119 mutex_enter(&sc->sc_slock); 1120 continue; 1121 } 1122 1123 disk_busy(sc->sc_dkdev); 1124 1125 /* 1126 * First read from the snapshotted block device unless 1127 * this request is completely covered by backing store. 1128 */ 1129 1130 cl = FSS_BTOCL(sc, dbtob(bp->b_blkno)); 1131 off = FSS_CLOFF(sc, dbtob(bp->b_blkno)); 1132 ch = FSS_BTOCL(sc, dbtob(bp->b_blkno)+bp->b_bcount-1); 1133 error = 0; 1134 bp->b_resid = 0; 1135 bp->b_error = 0; 1136 for (c = cl; c <= ch; c++) { 1137 if (isset(sc->sc_copied, c)) 1138 continue; 1139 mutex_exit(&sc->sc_slock); 1140 1141 /* Not on backing store, read from device. */ 1142 nbp = getiobuf(NULL, true); 1143 nbp->b_flags = B_READ; 1144 nbp->b_resid = nbp->b_bcount = bp->b_bcount; 1145 nbp->b_bufsize = bp->b_bcount; 1146 nbp->b_data = bp->b_data; 1147 nbp->b_blkno = bp->b_blkno; 1148 nbp->b_lblkno = 0; 1149 nbp->b_dev = sc->sc_bdev; 1150 SET(nbp->b_cflags, BC_BUSY); /* mark buffer busy */ 1151 1152 bdev_strategy(nbp); 1153 1154 error = biowait(nbp); 1155 if (error != 0) { 1156 bp->b_resid = bp->b_bcount; 1157 bp->b_error = nbp->b_error; 1158 disk_unbusy(sc->sc_dkdev, 0, is_read); 1159 biodone(bp); 1160 } 1161 putiobuf(nbp); 1162 1163 mutex_enter(&sc->sc_slock); 1164 break; 1165 } 1166 if (error) 1167 continue; 1168 1169 /* 1170 * Replace those parts that have been saved to backing store. 1171 */ 1172 1173 addr = bp->b_data; 1174 todo = bp->b_bcount; 1175 for (c = cl; c <= ch; c++, off = 0, todo -= len, addr += len) { 1176 len = FSS_CLSIZE(sc)-off; 1177 if (len > todo) 1178 len = todo; 1179 if (isclr(sc->sc_copied, c)) 1180 continue; 1181 mutex_exit(&sc->sc_slock); 1182 1183 indirp = fss_bs_indir(sc, c); 1184 if (indirp == NULL || *indirp == 0) { 1185 /* 1186 * Not on backing store. Either in cache 1187 * or hole in the snapshotted block device. 1188 */ 1189 1190 mutex_enter(&sc->sc_slock); 1191 for (scp = sc->sc_cache; scp < scl; scp++) 1192 if (scp->fc_type == FSS_CACHE_VALID && 1193 scp->fc_cluster == c) 1194 break; 1195 if (scp < scl) 1196 memcpy(addr, (char *)scp->fc_data+off, 1197 len); 1198 else 1199 memset(addr, 0, len); 1200 continue; 1201 } 1202 1203 /* 1204 * Read from backing store. 1205 */ 1206 error = 1207 fss_bs_io(sc, FSS_READ, *indirp, off, len, addr); 1208 1209 mutex_enter(&sc->sc_slock); 1210 if (error) { 1211 bp->b_resid = bp->b_bcount; 1212 bp->b_error = error; 1213 break; 1214 } 1215 } 1216 mutex_exit(&sc->sc_slock); 1217 1218 disk_unbusy(sc->sc_dkdev, (error ? 0 : bp->b_bcount), is_read); 1219 biodone(bp); 1220 1221 mutex_enter(&sc->sc_slock); 1222 } 1223 } 1224 1225 #ifdef _MODULE 1226 1227 #include <sys/module.h> 1228 1229 MODULE(MODULE_CLASS_DRIVER, fss, NULL); 1230 CFDRIVER_DECL(fss, DV_DISK, NULL); 1231 1232 static int 1233 fss_modcmd(modcmd_t cmd, void *arg) 1234 { 1235 int bmajor = -1, cmajor = -1, error = 0; 1236 1237 switch (cmd) { 1238 case MODULE_CMD_INIT: 1239 mutex_init(&fss_device_lock, MUTEX_DEFAULT, IPL_NONE); 1240 error = config_cfdriver_attach(&fss_cd); 1241 if (error) { 1242 mutex_destroy(&fss_device_lock); 1243 break; 1244 } 1245 error = config_cfattach_attach(fss_cd.cd_name, &fss_ca); 1246 if (error) { 1247 config_cfdriver_detach(&fss_cd); 1248 mutex_destroy(&fss_device_lock); 1249 break; 1250 } 1251 error = devsw_attach(fss_cd.cd_name, 1252 &fss_bdevsw, &bmajor, &fss_cdevsw, &cmajor); 1253 if (error == EEXIST) 1254 error = 0; 1255 if (error) { 1256 config_cfattach_detach(fss_cd.cd_name, &fss_ca); 1257 config_cfdriver_detach(&fss_cd); 1258 mutex_destroy(&fss_device_lock); 1259 break; 1260 } 1261 break; 1262 1263 case MODULE_CMD_FINI: 1264 error = config_cfattach_detach(fss_cd.cd_name, &fss_ca); 1265 if (error) 1266 break; 1267 config_cfdriver_detach(&fss_cd); 1268 devsw_detach(&fss_bdevsw, &fss_cdevsw); 1269 mutex_destroy(&fss_device_lock); 1270 break; 1271 1272 default: 1273 error = ENOTTY; 1274 break; 1275 } 1276 1277 return error; 1278 } 1279 1280 #endif /* _MODULE */ 1281
Indexes created Wed Nov 11 00:26:22 UTC 2026