fss.c revision 1.88
1 /* $NetBSD: fss.c,v 1.88 2014/03/16 05:20:26 dholland 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 1.88 2014/03/16 05:20:26 dholland 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/vfs_syscalls.h> /* For do_sys_unlink(). */ 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 .d_open = fss_open, 103 .d_close = fss_close, 104 .d_strategy = fss_strategy, fss_ioctl, 105 .d_dump = fss_dump, 106 .d_psize = fss_size, 107 .d_flag = D_DISK | D_MPSAFE 108 }; 109 110 const struct cdevsw fss_cdevsw = { 111 .d_open = fss_open, 112 .d_close = fss_close, 113 .d_read = fss_read, 114 .d_write = fss_write, 115 .d_ioctl = fss_ioctl, 116 .d_stop = nostop, 117 .d_tty = notty, 118 .d_poll = nopoll, 119 .d_mmap = nommap, 120 .d_kqfilter = nokqfilter, 121 .d_flag = D_DISK | D_MPSAFE 122 }; 123 124 static int fss_match(device_t, cfdata_t, void *); 125 static void fss_attach(device_t, device_t, void *); 126 static int fss_detach(device_t, int); 127 128 CFATTACH_DECL_NEW(fss, sizeof(struct fss_softc), 129 fss_match, fss_attach, fss_detach, NULL); 130 extern struct cfdriver fss_cd; 131 132 void 133 fssattach(int num) 134 { 135 136 mutex_init(&fss_device_lock, MUTEX_DEFAULT, IPL_NONE); 137 if (config_cfattach_attach(fss_cd.cd_name, &fss_ca)) 138 aprint_error("%s: unable to register\n", fss_cd.cd_name); 139 } 140 141 static int 142 fss_match(device_t self, cfdata_t cfdata, void *aux) 143 { 144 return 1; 145 } 146 147 static void 148 fss_attach(device_t parent, device_t self, void *aux) 149 { 150 struct fss_softc *sc = device_private(self); 151 152 sc->sc_dev = self; 153 sc->sc_bdev = NODEV; 154 mutex_init(&sc->sc_slock, MUTEX_DEFAULT, IPL_NONE); 155 mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_NONE); 156 cv_init(&sc->sc_work_cv, "fssbs"); 157 cv_init(&sc->sc_cache_cv, "cowwait"); 158 bufq_alloc(&sc->sc_bufq, "fcfs", 0); 159 sc->sc_dkdev = malloc(sizeof(*sc->sc_dkdev), M_DEVBUF, M_WAITOK); 160 sc->sc_dkdev->dk_info = NULL; 161 disk_init(sc->sc_dkdev, device_xname(self), NULL); 162 if (!pmf_device_register(self, NULL, NULL)) 163 aprint_error_dev(self, "couldn't establish power handler\n"); 164 165 if (fss_num_attached++ == 0) 166 vfs_hooks_attach(&fss_vfs_hooks); 167 } 168 169 static int 170 fss_detach(device_t self, int flags) 171 { 172 struct fss_softc *sc = device_private(self); 173 174 if (sc->sc_flags & FSS_ACTIVE) 175 return EBUSY; 176 177 if (--fss_num_attached == 0) 178 vfs_hooks_detach(&fss_vfs_hooks); 179 180 pmf_device_deregister(self); 181 mutex_destroy(&sc->sc_slock); 182 mutex_destroy(&sc->sc_lock); 183 cv_destroy(&sc->sc_work_cv); 184 cv_destroy(&sc->sc_cache_cv); 185 bufq_drain(sc->sc_bufq); 186 bufq_free(sc->sc_bufq); 187 disk_destroy(sc->sc_dkdev); 188 free(sc->sc_dkdev, M_DEVBUF); 189 190 return 0; 191 } 192 193 int 194 fss_open(dev_t dev, int flags, int mode, struct lwp *l) 195 { 196 int mflag; 197 cfdata_t cf; 198 struct fss_softc *sc; 199 200 mflag = (mode == S_IFCHR ? FSS_CDEV_OPEN : FSS_BDEV_OPEN); 201 202 mutex_enter(&fss_device_lock); 203 204 sc = device_lookup_private(&fss_cd, minor(dev)); 205 if (sc == NULL) { 206 cf = malloc(sizeof(*cf), M_DEVBUF, M_WAITOK); 207 cf->cf_name = fss_cd.cd_name; 208 cf->cf_atname = fss_cd.cd_name; 209 cf->cf_unit = minor(dev); 210 cf->cf_fstate = FSTATE_STAR; 211 sc = device_private(config_attach_pseudo(cf)); 212 if (sc == NULL) { 213 mutex_exit(&fss_device_lock); 214 return ENOMEM; 215 } 216 } 217 218 mutex_enter(&sc->sc_slock); 219 220 sc->sc_flags |= mflag; 221 222 mutex_exit(&sc->sc_slock); 223 mutex_exit(&fss_device_lock); 224 225 return 0; 226 } 227 228 int 229 fss_close(dev_t dev, int flags, int mode, struct lwp *l) 230 { 231 int mflag, error; 232 cfdata_t cf; 233 struct fss_softc *sc = device_lookup_private(&fss_cd, minor(dev)); 234 235 mflag = (mode == S_IFCHR ? FSS_CDEV_OPEN : FSS_BDEV_OPEN); 236 error = 0; 237 238 mutex_enter(&fss_device_lock); 239 restart: 240 mutex_enter(&sc->sc_slock); 241 if ((sc->sc_flags & (FSS_CDEV_OPEN|FSS_BDEV_OPEN)) != mflag) { 242 sc->sc_flags &= ~mflag; 243 mutex_exit(&sc->sc_slock); 244 mutex_exit(&fss_device_lock); 245 return 0; 246 } 247 if ((sc->sc_flags & FSS_ACTIVE) != 0 && 248 (sc->sc_uflags & FSS_UNCONFIG_ON_CLOSE) != 0) { 249 sc->sc_uflags &= ~FSS_UNCONFIG_ON_CLOSE; 250 mutex_exit(&sc->sc_slock); 251 error = fss_ioctl(dev, FSSIOCCLR, NULL, FWRITE, l); 252 goto restart; 253 } 254 if ((sc->sc_flags & FSS_ACTIVE) != 0) { 255 mutex_exit(&sc->sc_slock); 256 mutex_exit(&fss_device_lock); 257 return error; 258 } 259 260 KASSERT((sc->sc_flags & FSS_ACTIVE) == 0); 261 KASSERT((sc->sc_flags & (FSS_CDEV_OPEN|FSS_BDEV_OPEN)) == mflag); 262 mutex_exit(&sc->sc_slock); 263 cf = device_cfdata(sc->sc_dev); 264 error = config_detach(sc->sc_dev, DETACH_QUIET); 265 if (! error) 266 free(cf, M_DEVBUF); 267 mutex_exit(&fss_device_lock); 268 269 return error; 270 } 271 272 void 273 fss_strategy(struct buf *bp) 274 { 275 const bool write = ((bp->b_flags & B_READ) != B_READ); 276 struct fss_softc *sc = device_lookup_private(&fss_cd, minor(bp->b_dev)); 277 278 mutex_enter(&sc->sc_slock); 279 280 if (write || !FSS_ISVALID(sc)) { 281 282 mutex_exit(&sc->sc_slock); 283 284 bp->b_error = (write ? EROFS : ENXIO); 285 bp->b_resid = bp->b_bcount; 286 biodone(bp); 287 return; 288 } 289 290 bp->b_rawblkno = bp->b_blkno; 291 bufq_put(sc->sc_bufq, bp); 292 cv_signal(&sc->sc_work_cv); 293 294 mutex_exit(&sc->sc_slock); 295 } 296 297 int 298 fss_read(dev_t dev, struct uio *uio, int flags) 299 { 300 return physio(fss_strategy, NULL, dev, B_READ, minphys, uio); 301 } 302 303 int 304 fss_write(dev_t dev, struct uio *uio, int flags) 305 { 306 return physio(fss_strategy, NULL, dev, B_WRITE, minphys, uio); 307 } 308 309 int 310 fss_ioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l) 311 { 312 int error; 313 struct fss_softc *sc = device_lookup_private(&fss_cd, minor(dev)); 314 struct fss_set _fss; 315 struct fss_set *fss = (struct fss_set *)data; 316 struct fss_set50 *fss50 = (struct fss_set50 *)data; 317 struct fss_get *fsg = (struct fss_get *)data; 318 #ifndef _LP64 319 struct fss_get50 *fsg50 = (struct fss_get50 *)data; 320 #endif 321 322 switch (cmd) { 323 case FSSIOCSET50: 324 fss = &_fss; 325 fss->fss_mount = fss50->fss_mount; 326 fss->fss_bstore = fss50->fss_bstore; 327 fss->fss_csize = fss50->fss_csize; 328 fss->fss_flags = 0; 329 /* Fall through */ 330 case FSSIOCSET: 331 mutex_enter(&sc->sc_lock); 332 if ((flag & FWRITE) == 0) 333 error = EPERM; 334 else if ((sc->sc_flags & FSS_ACTIVE) != 0) 335 error = EBUSY; 336 else 337 error = fss_create_snapshot(sc, fss, l); 338 if (error == 0) 339 sc->sc_uflags = fss->fss_flags; 340 mutex_exit(&sc->sc_lock); 341 break; 342 343 case FSSIOCCLR: 344 mutex_enter(&sc->sc_lock); 345 if ((flag & FWRITE) == 0) 346 error = EPERM; 347 else if ((sc->sc_flags & FSS_ACTIVE) == 0) 348 error = ENXIO; 349 else 350 error = fss_delete_snapshot(sc, l); 351 mutex_exit(&sc->sc_lock); 352 break; 353 354 #ifndef _LP64 355 case FSSIOCGET50: 356 mutex_enter(&sc->sc_lock); 357 switch (sc->sc_flags & (FSS_PERSISTENT | FSS_ACTIVE)) { 358 case FSS_ACTIVE: 359 memcpy(fsg50->fsg_mount, sc->sc_mntname, MNAMELEN); 360 fsg50->fsg_csize = FSS_CLSIZE(sc); 361 timeval_to_timeval50(&sc->sc_time, &fsg50->fsg_time); 362 fsg50->fsg_mount_size = sc->sc_clcount; 363 fsg50->fsg_bs_size = sc->sc_clnext; 364 error = 0; 365 break; 366 case FSS_PERSISTENT | FSS_ACTIVE: 367 memcpy(fsg50->fsg_mount, sc->sc_mntname, MNAMELEN); 368 fsg50->fsg_csize = 0; 369 timeval_to_timeval50(&sc->sc_time, &fsg50->fsg_time); 370 fsg50->fsg_mount_size = 0; 371 fsg50->fsg_bs_size = 0; 372 error = 0; 373 break; 374 default: 375 error = ENXIO; 376 break; 377 } 378 mutex_exit(&sc->sc_lock); 379 break; 380 #endif /* _LP64 */ 381 382 case FSSIOCGET: 383 mutex_enter(&sc->sc_lock); 384 switch (sc->sc_flags & (FSS_PERSISTENT | FSS_ACTIVE)) { 385 case FSS_ACTIVE: 386 memcpy(fsg->fsg_mount, sc->sc_mntname, MNAMELEN); 387 fsg->fsg_csize = FSS_CLSIZE(sc); 388 fsg->fsg_time = sc->sc_time; 389 fsg->fsg_mount_size = sc->sc_clcount; 390 fsg->fsg_bs_size = sc->sc_clnext; 391 error = 0; 392 break; 393 case FSS_PERSISTENT | FSS_ACTIVE: 394 memcpy(fsg->fsg_mount, sc->sc_mntname, MNAMELEN); 395 fsg->fsg_csize = 0; 396 fsg->fsg_time = sc->sc_time; 397 fsg->fsg_mount_size = 0; 398 fsg->fsg_bs_size = 0; 399 error = 0; 400 break; 401 default: 402 error = ENXIO; 403 break; 404 } 405 mutex_exit(&sc->sc_lock); 406 break; 407 408 case FSSIOFSET: 409 mutex_enter(&sc->sc_slock); 410 sc->sc_uflags = *(int *)data; 411 mutex_exit(&sc->sc_slock); 412 error = 0; 413 break; 414 415 case FSSIOFGET: 416 mutex_enter(&sc->sc_slock); 417 *(int *)data = sc->sc_uflags; 418 mutex_exit(&sc->sc_slock); 419 error = 0; 420 break; 421 422 default: 423 error = EINVAL; 424 break; 425 } 426 427 return error; 428 } 429 430 int 431 fss_size(dev_t dev) 432 { 433 return -1; 434 } 435 436 int 437 fss_dump(dev_t dev, daddr_t blkno, void *va, 438 size_t size) 439 { 440 return EROFS; 441 } 442 443 /* 444 * An error occurred reading or writing the snapshot or backing store. 445 * If it is the first error log to console. 446 * The caller holds the mutex. 447 */ 448 static inline void 449 fss_error(struct fss_softc *sc, const char *msg) 450 { 451 452 if ((sc->sc_flags & (FSS_ACTIVE|FSS_ERROR)) == FSS_ACTIVE) 453 aprint_error_dev(sc->sc_dev, "snapshot invalid: %s\n", msg); 454 if ((sc->sc_flags & FSS_ACTIVE) == FSS_ACTIVE) 455 sc->sc_flags |= FSS_ERROR; 456 } 457 458 /* 459 * Allocate the variable sized parts of the softc and 460 * fork the kernel thread. 461 * 462 * The fields sc_clcount, sc_clshift, sc_cache_size and sc_indir_size 463 * must be initialized. 464 */ 465 static int 466 fss_softc_alloc(struct fss_softc *sc) 467 { 468 int i, error; 469 470 if ((sc->sc_flags & FSS_PERSISTENT) == 0) { 471 sc->sc_copied = 472 kmem_zalloc(howmany(sc->sc_clcount, NBBY), KM_SLEEP); 473 if (sc->sc_copied == NULL) 474 return(ENOMEM); 475 476 sc->sc_cache = kmem_alloc(sc->sc_cache_size * 477 sizeof(struct fss_cache), KM_SLEEP); 478 if (sc->sc_cache == NULL) 479 return(ENOMEM); 480 481 for (i = 0; i < sc->sc_cache_size; i++) { 482 sc->sc_cache[i].fc_type = FSS_CACHE_FREE; 483 sc->sc_cache[i].fc_data = 484 kmem_alloc(FSS_CLSIZE(sc), KM_SLEEP); 485 if (sc->sc_cache[i].fc_data == NULL) 486 return(ENOMEM); 487 cv_init(&sc->sc_cache[i].fc_state_cv, "cowwait1"); 488 } 489 490 sc->sc_indir_valid = 491 kmem_zalloc(howmany(sc->sc_indir_size, NBBY), KM_SLEEP); 492 if (sc->sc_indir_valid == NULL) 493 return(ENOMEM); 494 495 sc->sc_indir_data = kmem_zalloc(FSS_CLSIZE(sc), KM_SLEEP); 496 if (sc->sc_indir_data == NULL) 497 return(ENOMEM); 498 } else { 499 sc->sc_copied = NULL; 500 sc->sc_cache = NULL; 501 sc->sc_indir_valid = NULL; 502 sc->sc_indir_data = NULL; 503 } 504 505 sc->sc_flags |= FSS_BS_THREAD; 506 if ((error = kthread_create(PRI_BIO, KTHREAD_MUSTJOIN, NULL, 507 fss_bs_thread, sc, &sc->sc_bs_lwp, 508 "%s", device_xname(sc->sc_dev))) != 0) { 509 sc->sc_flags &= ~FSS_BS_THREAD; 510 return error; 511 } 512 513 disk_attach(sc->sc_dkdev); 514 515 return 0; 516 } 517 518 /* 519 * Free the variable sized parts of the softc. 520 */ 521 static void 522 fss_softc_free(struct fss_softc *sc) 523 { 524 int i; 525 526 if ((sc->sc_flags & FSS_BS_THREAD) != 0) { 527 mutex_enter(&sc->sc_slock); 528 sc->sc_flags &= ~FSS_BS_THREAD; 529 cv_signal(&sc->sc_work_cv); 530 mutex_exit(&sc->sc_slock); 531 kthread_join(sc->sc_bs_lwp); 532 533 disk_detach(sc->sc_dkdev); 534 } 535 536 if (sc->sc_copied != NULL) 537 kmem_free(sc->sc_copied, howmany(sc->sc_clcount, NBBY)); 538 sc->sc_copied = NULL; 539 540 if (sc->sc_cache != NULL) { 541 for (i = 0; i < sc->sc_cache_size; i++) 542 if (sc->sc_cache[i].fc_data != NULL) { 543 cv_destroy(&sc->sc_cache[i].fc_state_cv); 544 kmem_free(sc->sc_cache[i].fc_data, 545 FSS_CLSIZE(sc)); 546 } 547 kmem_free(sc->sc_cache, 548 sc->sc_cache_size*sizeof(struct fss_cache)); 549 } 550 sc->sc_cache = NULL; 551 552 if (sc->sc_indir_valid != NULL) 553 kmem_free(sc->sc_indir_valid, howmany(sc->sc_indir_size, NBBY)); 554 sc->sc_indir_valid = NULL; 555 556 if (sc->sc_indir_data != NULL) 557 kmem_free(sc->sc_indir_data, FSS_CLSIZE(sc)); 558 sc->sc_indir_data = NULL; 559 } 560 561 /* 562 * Set all active snapshots on this file system into ERROR state. 563 */ 564 static void 565 fss_unmount_hook(struct mount *mp) 566 { 567 int i; 568 struct fss_softc *sc; 569 570 mutex_enter(&fss_device_lock); 571 for (i = 0; i < fss_cd.cd_ndevs; i++) { 572 if ((sc = device_lookup_private(&fss_cd, i)) == NULL) 573 continue; 574 mutex_enter(&sc->sc_slock); 575 if ((sc->sc_flags & FSS_ACTIVE) != 0 && 576 sc->sc_mount == mp) 577 fss_error(sc, "forced unmount"); 578 mutex_exit(&sc->sc_slock); 579 } 580 mutex_exit(&fss_device_lock); 581 } 582 583 /* 584 * A buffer is written to the snapshotted block device. Copy to 585 * backing store if needed. 586 */ 587 static int 588 fss_copy_on_write(void *v, struct buf *bp, bool data_valid) 589 { 590 int error; 591 u_int32_t cl, ch, c; 592 struct fss_softc *sc = v; 593 594 mutex_enter(&sc->sc_slock); 595 if (!FSS_ISVALID(sc)) { 596 mutex_exit(&sc->sc_slock); 597 return 0; 598 } 599 600 cl = FSS_BTOCL(sc, dbtob(bp->b_blkno)); 601 ch = FSS_BTOCL(sc, dbtob(bp->b_blkno)+bp->b_bcount-1); 602 error = 0; 603 if (curlwp == uvm.pagedaemon_lwp) { 604 for (c = cl; c <= ch; c++) 605 if (isclr(sc->sc_copied, c)) { 606 error = ENOMEM; 607 break; 608 } 609 } 610 mutex_exit(&sc->sc_slock); 611 612 if (error == 0) 613 for (c = cl; c <= ch; c++) { 614 error = fss_read_cluster(sc, c); 615 if (error) 616 break; 617 } 618 619 return error; 620 } 621 622 /* 623 * Lookup and open needed files. 624 * 625 * For file system internal snapshot initializes sc_mntname, sc_mount, 626 * sc_bs_vp and sc_time. 627 * 628 * Otherwise returns dev and size of the underlying block device. 629 * Initializes sc_mntname, sc_mount, sc_bdev, sc_bs_vp and sc_mount 630 */ 631 static int 632 fss_create_files(struct fss_softc *sc, struct fss_set *fss, 633 off_t *bsize, struct lwp *l) 634 { 635 int error, bits, fsbsize; 636 uint64_t numsec; 637 unsigned int secsize; 638 struct timespec ts; 639 /* nd -> nd2 to reduce mistakes while updating only some namei calls */ 640 struct pathbuf *pb2; 641 struct nameidata nd2; 642 struct vnode *vp; 643 644 /* 645 * Get the mounted file system. 646 */ 647 648 error = namei_simple_user(fss->fss_mount, 649 NSM_FOLLOW_NOEMULROOT, &vp); 650 if (error != 0) 651 return error; 652 653 if ((vp->v_vflag & VV_ROOT) != VV_ROOT) { 654 vrele(vp); 655 return EINVAL; 656 } 657 658 sc->sc_mount = vp->v_mount; 659 memcpy(sc->sc_mntname, sc->sc_mount->mnt_stat.f_mntonname, MNAMELEN); 660 661 vrele(vp); 662 663 /* 664 * Check for file system internal snapshot. 665 */ 666 667 error = namei_simple_user(fss->fss_bstore, 668 NSM_FOLLOW_NOEMULROOT, &vp); 669 if (error != 0) 670 return error; 671 672 if (vp->v_type == VREG && vp->v_mount == sc->sc_mount) { 673 sc->sc_flags |= FSS_PERSISTENT; 674 sc->sc_bs_vp = vp; 675 676 fsbsize = sc->sc_bs_vp->v_mount->mnt_stat.f_iosize; 677 bits = sizeof(sc->sc_bs_bshift)*NBBY; 678 for (sc->sc_bs_bshift = 1; sc->sc_bs_bshift < bits; 679 sc->sc_bs_bshift++) 680 if (FSS_FSBSIZE(sc) == fsbsize) 681 break; 682 if (sc->sc_bs_bshift >= bits) 683 return EINVAL; 684 685 sc->sc_bs_bmask = FSS_FSBSIZE(sc)-1; 686 sc->sc_clshift = 0; 687 688 if ((fss->fss_flags & FSS_UNLINK_ON_CREATE) != 0) { 689 error = do_sys_unlink(fss->fss_bstore, UIO_USERSPACE); 690 if (error) 691 return error; 692 } 693 error = vn_lock(vp, LK_EXCLUSIVE); 694 if (error != 0) 695 return error; 696 error = VFS_SNAPSHOT(sc->sc_mount, sc->sc_bs_vp, &ts); 697 TIMESPEC_TO_TIMEVAL(&sc->sc_time, &ts); 698 699 VOP_UNLOCK(sc->sc_bs_vp); 700 701 return error; 702 } 703 vrele(vp); 704 705 /* 706 * Get the block device it is mounted on and its size. 707 */ 708 709 error = spec_node_lookup_by_mount(sc->sc_mount, &vp); 710 if (error) 711 return error; 712 sc->sc_bdev = vp->v_rdev; 713 714 error = getdisksize(vp, &numsec, &secsize); 715 vrele(vp); 716 if (error) 717 return error; 718 719 *bsize = (off_t)numsec*secsize; 720 721 /* 722 * Get the backing store 723 */ 724 725 error = pathbuf_copyin(fss->fss_bstore, &pb2); 726 if (error) { 727 return error; 728 } 729 NDINIT(&nd2, LOOKUP, FOLLOW, pb2); 730 if ((error = vn_open(&nd2, FREAD|FWRITE, 0)) != 0) { 731 pathbuf_destroy(pb2); 732 return error; 733 } 734 VOP_UNLOCK(nd2.ni_vp); 735 736 sc->sc_bs_vp = nd2.ni_vp; 737 738 if (nd2.ni_vp->v_type != VREG && nd2.ni_vp->v_type != VCHR) { 739 pathbuf_destroy(pb2); 740 return EINVAL; 741 } 742 pathbuf_destroy(pb2); 743 744 if ((fss->fss_flags & FSS_UNLINK_ON_CREATE) != 0) { 745 error = do_sys_unlink(fss->fss_bstore, UIO_USERSPACE); 746 if (error) 747 return error; 748 } 749 if (sc->sc_bs_vp->v_type == VREG) { 750 fsbsize = sc->sc_bs_vp->v_mount->mnt_stat.f_iosize; 751 if (fsbsize & (fsbsize-1)) /* No power of two */ 752 return EINVAL; 753 for (sc->sc_bs_bshift = 1; sc->sc_bs_bshift < 32; 754 sc->sc_bs_bshift++) 755 if (FSS_FSBSIZE(sc) == fsbsize) 756 break; 757 if (sc->sc_bs_bshift >= 32) 758 return EINVAL; 759 sc->sc_bs_bmask = FSS_FSBSIZE(sc)-1; 760 } else { 761 sc->sc_bs_bshift = DEV_BSHIFT; 762 sc->sc_bs_bmask = FSS_FSBSIZE(sc)-1; 763 } 764 765 return 0; 766 } 767 768 /* 769 * Create a snapshot. 770 */ 771 static int 772 fss_create_snapshot(struct fss_softc *sc, struct fss_set *fss, struct lwp *l) 773 { 774 int len, error; 775 u_int32_t csize; 776 off_t bsize; 777 778 bsize = 0; /* XXX gcc */ 779 780 /* 781 * Open needed files. 782 */ 783 if ((error = fss_create_files(sc, fss, &bsize, l)) != 0) 784 goto bad; 785 786 if (sc->sc_flags & FSS_PERSISTENT) { 787 fss_softc_alloc(sc); 788 sc->sc_flags |= FSS_ACTIVE; 789 return 0; 790 } 791 792 /* 793 * Set cluster size. Must be a power of two and 794 * a multiple of backing store block size. 795 */ 796 if (fss->fss_csize <= 0) 797 csize = MAXPHYS; 798 else 799 csize = fss->fss_csize; 800 if (bsize/csize > FSS_CLUSTER_MAX) 801 csize = bsize/FSS_CLUSTER_MAX+1; 802 803 for (sc->sc_clshift = sc->sc_bs_bshift; sc->sc_clshift < 32; 804 sc->sc_clshift++) 805 if (FSS_CLSIZE(sc) >= csize) 806 break; 807 if (sc->sc_clshift >= 32) { 808 error = EINVAL; 809 goto bad; 810 } 811 sc->sc_clmask = FSS_CLSIZE(sc)-1; 812 813 /* 814 * Set number of cache slots. 815 */ 816 if (FSS_CLSIZE(sc) <= 8192) 817 sc->sc_cache_size = 32; 818 else if (FSS_CLSIZE(sc) <= 65536) 819 sc->sc_cache_size = 8; 820 else 821 sc->sc_cache_size = 4; 822 823 /* 824 * Set number of clusters and size of last cluster. 825 */ 826 sc->sc_clcount = FSS_BTOCL(sc, bsize-1)+1; 827 sc->sc_clresid = FSS_CLOFF(sc, bsize-1)+1; 828 829 /* 830 * Set size of indirect table. 831 */ 832 len = sc->sc_clcount*sizeof(u_int32_t); 833 sc->sc_indir_size = FSS_BTOCL(sc, len)+1; 834 sc->sc_clnext = sc->sc_indir_size; 835 sc->sc_indir_cur = 0; 836 837 if ((error = fss_softc_alloc(sc)) != 0) 838 goto bad; 839 840 /* 841 * Activate the snapshot. 842 */ 843 844 if ((error = vfs_suspend(sc->sc_mount, 0)) != 0) 845 goto bad; 846 847 microtime(&sc->sc_time); 848 849 error = fscow_establish(sc->sc_mount, fss_copy_on_write, sc); 850 if (error == 0) 851 sc->sc_flags |= FSS_ACTIVE; 852 853 vfs_resume(sc->sc_mount); 854 855 if (error != 0) 856 goto bad; 857 858 aprint_debug_dev(sc->sc_dev, "%s snapshot active\n", sc->sc_mntname); 859 aprint_debug_dev(sc->sc_dev, 860 "%u clusters of %u, %u cache slots, %u indir clusters\n", 861 sc->sc_clcount, FSS_CLSIZE(sc), 862 sc->sc_cache_size, sc->sc_indir_size); 863 864 return 0; 865 866 bad: 867 fss_softc_free(sc); 868 if (sc->sc_bs_vp != NULL) { 869 if (sc->sc_flags & FSS_PERSISTENT) 870 vrele(sc->sc_bs_vp); 871 else 872 vn_close(sc->sc_bs_vp, FREAD|FWRITE, l->l_cred); 873 } 874 sc->sc_bs_vp = NULL; 875 876 return error; 877 } 878 879 /* 880 * Delete a snapshot. 881 */ 882 static int 883 fss_delete_snapshot(struct fss_softc *sc, struct lwp *l) 884 { 885 886 if ((sc->sc_flags & FSS_PERSISTENT) == 0) 887 fscow_disestablish(sc->sc_mount, fss_copy_on_write, sc); 888 889 mutex_enter(&sc->sc_slock); 890 sc->sc_flags &= ~(FSS_ACTIVE|FSS_ERROR); 891 sc->sc_mount = NULL; 892 sc->sc_bdev = NODEV; 893 mutex_exit(&sc->sc_slock); 894 895 fss_softc_free(sc); 896 if (sc->sc_flags & FSS_PERSISTENT) 897 vrele(sc->sc_bs_vp); 898 else 899 vn_close(sc->sc_bs_vp, FREAD|FWRITE, l->l_cred); 900 sc->sc_bs_vp = NULL; 901 sc->sc_flags &= ~FSS_PERSISTENT; 902 903 return 0; 904 } 905 906 /* 907 * Read a cluster from the snapshotted block device to the cache. 908 */ 909 static int 910 fss_read_cluster(struct fss_softc *sc, u_int32_t cl) 911 { 912 int error, todo, offset, len; 913 daddr_t dblk; 914 struct buf *bp, *mbp; 915 struct fss_cache *scp, *scl; 916 917 /* 918 * Get a free cache slot. 919 */ 920 scl = sc->sc_cache+sc->sc_cache_size; 921 922 mutex_enter(&sc->sc_slock); 923 924 restart: 925 if (isset(sc->sc_copied, cl) || !FSS_ISVALID(sc)) { 926 mutex_exit(&sc->sc_slock); 927 return 0; 928 } 929 930 for (scp = sc->sc_cache; scp < scl; scp++) 931 if (scp->fc_cluster == cl) { 932 if (scp->fc_type == FSS_CACHE_VALID) { 933 mutex_exit(&sc->sc_slock); 934 return 0; 935 } else if (scp->fc_type == FSS_CACHE_BUSY) { 936 cv_wait(&scp->fc_state_cv, &sc->sc_slock); 937 goto restart; 938 } 939 } 940 941 for (scp = sc->sc_cache; scp < scl; scp++) 942 if (scp->fc_type == FSS_CACHE_FREE) { 943 scp->fc_type = FSS_CACHE_BUSY; 944 scp->fc_cluster = cl; 945 break; 946 } 947 if (scp >= scl) { 948 cv_wait(&sc->sc_cache_cv, &sc->sc_slock); 949 goto restart; 950 } 951 952 mutex_exit(&sc->sc_slock); 953 954 /* 955 * Start the read. 956 */ 957 dblk = btodb(FSS_CLTOB(sc, cl)); 958 if (cl == sc->sc_clcount-1) { 959 todo = sc->sc_clresid; 960 memset((char *)scp->fc_data + todo, 0, FSS_CLSIZE(sc) - todo); 961 } else 962 todo = FSS_CLSIZE(sc); 963 offset = 0; 964 mbp = getiobuf(NULL, true); 965 mbp->b_bufsize = todo; 966 mbp->b_data = scp->fc_data; 967 mbp->b_resid = mbp->b_bcount = todo; 968 mbp->b_flags = B_READ; 969 mbp->b_cflags = BC_BUSY; 970 mbp->b_dev = sc->sc_bdev; 971 while (todo > 0) { 972 len = todo; 973 if (len > MAXPHYS) 974 len = MAXPHYS; 975 if (btodb(FSS_CLTOB(sc, cl)) == dblk && len == todo) 976 bp = mbp; 977 else { 978 bp = getiobuf(NULL, true); 979 nestiobuf_setup(mbp, bp, offset, len); 980 } 981 bp->b_lblkno = 0; 982 bp->b_blkno = dblk; 983 bdev_strategy(bp); 984 dblk += btodb(len); 985 offset += len; 986 todo -= len; 987 } 988 error = biowait(mbp); 989 putiobuf(mbp); 990 991 mutex_enter(&sc->sc_slock); 992 scp->fc_type = (error ? FSS_CACHE_FREE : FSS_CACHE_VALID); 993 cv_broadcast(&scp->fc_state_cv); 994 if (error == 0) { 995 setbit(sc->sc_copied, scp->fc_cluster); 996 cv_signal(&sc->sc_work_cv); 997 } 998 mutex_exit(&sc->sc_slock); 999 1000 return error; 1001 } 1002 1003 /* 1004 * Read/write clusters from/to backing store. 1005 * For persistent snapshots must be called with cl == 0. off is the 1006 * offset into the snapshot. 1007 */ 1008 static int 1009 fss_bs_io(struct fss_softc *sc, fss_io_type rw, 1010 u_int32_t cl, off_t off, int len, void *data) 1011 { 1012 int error; 1013 1014 off += FSS_CLTOB(sc, cl); 1015 1016 vn_lock(sc->sc_bs_vp, LK_EXCLUSIVE|LK_RETRY); 1017 1018 error = vn_rdwr((rw == FSS_READ ? UIO_READ : UIO_WRITE), sc->sc_bs_vp, 1019 data, len, off, UIO_SYSSPACE, 1020 IO_ADV_ENCODE(POSIX_FADV_NOREUSE) | IO_NODELOCKED, 1021 sc->sc_bs_lwp->l_cred, NULL, NULL); 1022 if (error == 0) { 1023 mutex_enter(sc->sc_bs_vp->v_interlock); 1024 error = VOP_PUTPAGES(sc->sc_bs_vp, trunc_page(off), 1025 round_page(off+len), PGO_CLEANIT | PGO_FREE | PGO_SYNCIO); 1026 } 1027 1028 VOP_UNLOCK(sc->sc_bs_vp); 1029 1030 return error; 1031 } 1032 1033 /* 1034 * Get a pointer to the indirect slot for this cluster. 1035 */ 1036 static u_int32_t * 1037 fss_bs_indir(struct fss_softc *sc, u_int32_t cl) 1038 { 1039 u_int32_t icl; 1040 int ioff; 1041 1042 icl = cl/(FSS_CLSIZE(sc)/sizeof(u_int32_t)); 1043 ioff = cl%(FSS_CLSIZE(sc)/sizeof(u_int32_t)); 1044 1045 if (sc->sc_indir_cur == icl) 1046 return &sc->sc_indir_data[ioff]; 1047 1048 if (sc->sc_indir_dirty) { 1049 if (fss_bs_io(sc, FSS_WRITE, sc->sc_indir_cur, 0, 1050 FSS_CLSIZE(sc), (void *)sc->sc_indir_data) != 0) 1051 return NULL; 1052 setbit(sc->sc_indir_valid, sc->sc_indir_cur); 1053 } 1054 1055 sc->sc_indir_dirty = 0; 1056 sc->sc_indir_cur = icl; 1057 1058 if (isset(sc->sc_indir_valid, sc->sc_indir_cur)) { 1059 if (fss_bs_io(sc, FSS_READ, sc->sc_indir_cur, 0, 1060 FSS_CLSIZE(sc), (void *)sc->sc_indir_data) != 0) 1061 return NULL; 1062 } else 1063 memset(sc->sc_indir_data, 0, FSS_CLSIZE(sc)); 1064 1065 return &sc->sc_indir_data[ioff]; 1066 } 1067 1068 /* 1069 * The kernel thread (one for every active snapshot). 1070 * 1071 * After wakeup it cleans the cache and runs the I/O requests. 1072 */ 1073 static void 1074 fss_bs_thread(void *arg) 1075 { 1076 bool thread_idle, is_valid; 1077 int error, i, todo, len, crotor, is_read; 1078 long off; 1079 char *addr; 1080 u_int32_t c, cl, ch, *indirp; 1081 struct buf *bp, *nbp; 1082 struct fss_softc *sc; 1083 struct fss_cache *scp, *scl; 1084 1085 sc = arg; 1086 scl = sc->sc_cache+sc->sc_cache_size; 1087 crotor = 0; 1088 thread_idle = false; 1089 1090 mutex_enter(&sc->sc_slock); 1091 1092 for (;;) { 1093 if (thread_idle) 1094 cv_wait(&sc->sc_work_cv, &sc->sc_slock); 1095 thread_idle = true; 1096 if ((sc->sc_flags & FSS_BS_THREAD) == 0) { 1097 mutex_exit(&sc->sc_slock); 1098 kthread_exit(0); 1099 } 1100 1101 /* 1102 * Process I/O requests (persistent) 1103 */ 1104 1105 if (sc->sc_flags & FSS_PERSISTENT) { 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 mutex_exit(&sc->sc_slock); 1112 1113 if (is_valid) { 1114 disk_busy(sc->sc_dkdev); 1115 error = fss_bs_io(sc, FSS_READ, 0, 1116 dbtob(bp->b_blkno), bp->b_bcount, 1117 bp->b_data); 1118 disk_unbusy(sc->sc_dkdev, 1119 (error ? 0 : bp->b_bcount), is_read); 1120 } else 1121 error = ENXIO; 1122 1123 bp->b_error = error; 1124 bp->b_resid = (error ? bp->b_bcount : 0); 1125 biodone(bp); 1126 1127 mutex_enter(&sc->sc_slock); 1128 continue; 1129 } 1130 1131 /* 1132 * Clean the cache 1133 */ 1134 for (i = 0; i < sc->sc_cache_size; i++) { 1135 crotor = (crotor + 1) % sc->sc_cache_size; 1136 scp = sc->sc_cache + crotor; 1137 if (scp->fc_type != FSS_CACHE_VALID) 1138 continue; 1139 mutex_exit(&sc->sc_slock); 1140 1141 thread_idle = false; 1142 indirp = fss_bs_indir(sc, scp->fc_cluster); 1143 if (indirp != NULL) { 1144 error = fss_bs_io(sc, FSS_WRITE, sc->sc_clnext, 1145 0, FSS_CLSIZE(sc), scp->fc_data); 1146 } else 1147 error = EIO; 1148 1149 mutex_enter(&sc->sc_slock); 1150 if (error == 0) { 1151 *indirp = sc->sc_clnext++; 1152 sc->sc_indir_dirty = 1; 1153 } else 1154 fss_error(sc, "write error on backing store"); 1155 1156 scp->fc_type = FSS_CACHE_FREE; 1157 cv_signal(&sc->sc_cache_cv); 1158 break; 1159 } 1160 1161 /* 1162 * Process I/O requests 1163 */ 1164 if ((bp = bufq_get(sc->sc_bufq)) == NULL) 1165 continue; 1166 is_valid = FSS_ISVALID(sc); 1167 is_read = (bp->b_flags & B_READ); 1168 thread_idle = false; 1169 1170 if (!is_valid) { 1171 mutex_exit(&sc->sc_slock); 1172 1173 bp->b_error = ENXIO; 1174 bp->b_resid = bp->b_bcount; 1175 biodone(bp); 1176 1177 mutex_enter(&sc->sc_slock); 1178 continue; 1179 } 1180 1181 disk_busy(sc->sc_dkdev); 1182 1183 /* 1184 * First read from the snapshotted block device unless 1185 * this request is completely covered by backing store. 1186 */ 1187 1188 cl = FSS_BTOCL(sc, dbtob(bp->b_blkno)); 1189 off = FSS_CLOFF(sc, dbtob(bp->b_blkno)); 1190 ch = FSS_BTOCL(sc, dbtob(bp->b_blkno)+bp->b_bcount-1); 1191 error = 0; 1192 bp->b_resid = 0; 1193 bp->b_error = 0; 1194 for (c = cl; c <= ch; c++) { 1195 if (isset(sc->sc_copied, c)) 1196 continue; 1197 mutex_exit(&sc->sc_slock); 1198 1199 /* Not on backing store, read from device. */ 1200 nbp = getiobuf(NULL, true); 1201 nbp->b_flags = B_READ; 1202 nbp->b_resid = nbp->b_bcount = bp->b_bcount; 1203 nbp->b_bufsize = bp->b_bcount; 1204 nbp->b_data = bp->b_data; 1205 nbp->b_blkno = bp->b_blkno; 1206 nbp->b_lblkno = 0; 1207 nbp->b_dev = sc->sc_bdev; 1208 SET(nbp->b_cflags, BC_BUSY); /* mark buffer busy */ 1209 1210 bdev_strategy(nbp); 1211 1212 error = biowait(nbp); 1213 if (error != 0) { 1214 bp->b_resid = bp->b_bcount; 1215 bp->b_error = nbp->b_error; 1216 disk_unbusy(sc->sc_dkdev, 0, is_read); 1217 biodone(bp); 1218 } 1219 putiobuf(nbp); 1220 1221 mutex_enter(&sc->sc_slock); 1222 break; 1223 } 1224 if (error) 1225 continue; 1226 1227 /* 1228 * Replace those parts that have been saved to backing store. 1229 */ 1230 1231 addr = bp->b_data; 1232 todo = bp->b_bcount; 1233 for (c = cl; c <= ch; c++, off = 0, todo -= len, addr += len) { 1234 len = FSS_CLSIZE(sc)-off; 1235 if (len > todo) 1236 len = todo; 1237 if (isclr(sc->sc_copied, c)) 1238 continue; 1239 mutex_exit(&sc->sc_slock); 1240 1241 indirp = fss_bs_indir(sc, c); 1242 if (indirp == NULL || *indirp == 0) { 1243 /* 1244 * Not on backing store. Either in cache 1245 * or hole in the snapshotted block device. 1246 */ 1247 1248 mutex_enter(&sc->sc_slock); 1249 for (scp = sc->sc_cache; scp < scl; scp++) 1250 if (scp->fc_type == FSS_CACHE_VALID && 1251 scp->fc_cluster == c) 1252 break; 1253 if (scp < scl) 1254 memcpy(addr, (char *)scp->fc_data+off, 1255 len); 1256 else 1257 memset(addr, 0, len); 1258 continue; 1259 } 1260 1261 /* 1262 * Read from backing store. 1263 */ 1264 error = 1265 fss_bs_io(sc, FSS_READ, *indirp, off, len, addr); 1266 1267 mutex_enter(&sc->sc_slock); 1268 if (error) { 1269 bp->b_resid = bp->b_bcount; 1270 bp->b_error = error; 1271 break; 1272 } 1273 } 1274 mutex_exit(&sc->sc_slock); 1275 1276 disk_unbusy(sc->sc_dkdev, (error ? 0 : bp->b_bcount), is_read); 1277 biodone(bp); 1278 1279 mutex_enter(&sc->sc_slock); 1280 } 1281 } 1282 1283 #ifdef _MODULE 1284 1285 #include <sys/module.h> 1286 1287 MODULE(MODULE_CLASS_DRIVER, fss, NULL); 1288 CFDRIVER_DECL(fss, DV_DISK, NULL); 1289 1290 static int 1291 fss_modcmd(modcmd_t cmd, void *arg) 1292 { 1293 int bmajor = -1, cmajor = -1, error = 0; 1294 1295 switch (cmd) { 1296 case MODULE_CMD_INIT: 1297 mutex_init(&fss_device_lock, MUTEX_DEFAULT, IPL_NONE); 1298 error = config_cfdriver_attach(&fss_cd); 1299 if (error) { 1300 mutex_destroy(&fss_device_lock); 1301 break; 1302 } 1303 error = config_cfattach_attach(fss_cd.cd_name, &fss_ca); 1304 if (error) { 1305 config_cfdriver_detach(&fss_cd); 1306 mutex_destroy(&fss_device_lock); 1307 break; 1308 } 1309 error = devsw_attach(fss_cd.cd_name, 1310 &fss_bdevsw, &bmajor, &fss_cdevsw, &cmajor); 1311 if (error == EEXIST) 1312 error = 0; 1313 if (error) { 1314 config_cfattach_detach(fss_cd.cd_name, &fss_ca); 1315 config_cfdriver_detach(&fss_cd); 1316 mutex_destroy(&fss_device_lock); 1317 break; 1318 } 1319 break; 1320 1321 case MODULE_CMD_FINI: 1322 error = config_cfattach_detach(fss_cd.cd_name, &fss_ca); 1323 if (error) 1324 break; 1325 config_cfdriver_detach(&fss_cd); 1326 devsw_detach(&fss_bdevsw, &fss_cdevsw); 1327 mutex_destroy(&fss_device_lock); 1328 break; 1329 1330 default: 1331 error = ENOTTY; 1332 break; 1333 } 1334 1335 return error; 1336 } 1337 1338 #endif /* _MODULE */ 1339
Indexes created Wed Nov 11 00:26:22 UTC 2026