fss.c revision 1.106
1 /* $NetBSD: fss.c,v 1.106 2018/08/29 09:04:40 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 1.106 2018/08/29 09:04:40 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/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 #include "ioconf.h" 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 *, size_t *); 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 kcondvar_t fss_device_cv; /* Serialize snapshot creation. */ 97 static bool fss_creating = false; /* Currently creating a snapshot. */ 98 static int fss_num_attached = 0; /* Number of attached devices. */ 99 static struct vfs_hooks fss_vfs_hooks = { 100 .vh_unmount = fss_unmount_hook 101 }; 102 103 const struct bdevsw fss_bdevsw = { 104 .d_open = fss_open, 105 .d_close = fss_close, 106 .d_strategy = fss_strategy, 107 .d_ioctl = fss_ioctl, 108 .d_dump = fss_dump, 109 .d_psize = fss_size, 110 .d_discard = nodiscard, 111 .d_flag = D_DISK | D_MPSAFE 112 }; 113 114 const struct cdevsw fss_cdevsw = { 115 .d_open = fss_open, 116 .d_close = fss_close, 117 .d_read = fss_read, 118 .d_write = fss_write, 119 .d_ioctl = fss_ioctl, 120 .d_stop = nostop, 121 .d_tty = notty, 122 .d_poll = nopoll, 123 .d_mmap = nommap, 124 .d_kqfilter = nokqfilter, 125 .d_discard = nodiscard, 126 .d_flag = D_DISK | D_MPSAFE 127 }; 128 129 static int fss_match(device_t, cfdata_t, void *); 130 static void fss_attach(device_t, device_t, void *); 131 static int fss_detach(device_t, int); 132 133 CFATTACH_DECL_NEW(fss, sizeof(struct fss_softc), 134 fss_match, fss_attach, fss_detach, NULL); 135 136 void 137 fssattach(int num) 138 { 139 140 mutex_init(&fss_device_lock, MUTEX_DEFAULT, IPL_NONE); 141 cv_init(&fss_device_cv, "snapwait"); 142 if (config_cfattach_attach(fss_cd.cd_name, &fss_ca)) 143 aprint_error("%s: unable to register\n", fss_cd.cd_name); 144 } 145 146 static int 147 fss_match(device_t self, cfdata_t cfdata, void *aux) 148 { 149 return 1; 150 } 151 152 static void 153 fss_attach(device_t parent, device_t self, void *aux) 154 { 155 struct fss_softc *sc = device_private(self); 156 157 sc->sc_dev = self; 158 sc->sc_bdev = NODEV; 159 mutex_init(&sc->sc_slock, MUTEX_DEFAULT, IPL_NONE); 160 cv_init(&sc->sc_work_cv, "fssbs"); 161 cv_init(&sc->sc_cache_cv, "cowwait"); 162 bufq_alloc(&sc->sc_bufq, "fcfs", 0); 163 sc->sc_dkdev = malloc(sizeof(*sc->sc_dkdev), M_DEVBUF, M_WAITOK); 164 sc->sc_dkdev->dk_info = NULL; 165 disk_init(sc->sc_dkdev, device_xname(self), NULL); 166 if (!pmf_device_register(self, NULL, NULL)) 167 aprint_error_dev(self, "couldn't establish power handler\n"); 168 169 if (fss_num_attached++ == 0) 170 vfs_hooks_attach(&fss_vfs_hooks); 171 } 172 173 static int 174 fss_detach(device_t self, int flags) 175 { 176 struct fss_softc *sc = device_private(self); 177 178 mutex_enter(&sc->sc_slock); 179 if (sc->sc_state != FSS_IDLE) { 180 mutex_exit(&sc->sc_slock); 181 return EBUSY; 182 } 183 mutex_exit(&sc->sc_slock); 184 185 if (--fss_num_attached == 0) 186 vfs_hooks_detach(&fss_vfs_hooks); 187 188 pmf_device_deregister(self); 189 mutex_destroy(&sc->sc_slock); 190 cv_destroy(&sc->sc_work_cv); 191 cv_destroy(&sc->sc_cache_cv); 192 bufq_drain(sc->sc_bufq); 193 bufq_free(sc->sc_bufq); 194 disk_destroy(sc->sc_dkdev); 195 free(sc->sc_dkdev, M_DEVBUF); 196 197 return 0; 198 } 199 200 int 201 fss_open(dev_t dev, int flags, int mode, struct lwp *l) 202 { 203 int mflag; 204 cfdata_t cf; 205 struct fss_softc *sc; 206 207 mflag = (mode == S_IFCHR ? FSS_CDEV_OPEN : FSS_BDEV_OPEN); 208 209 mutex_enter(&fss_device_lock); 210 211 sc = device_lookup_private(&fss_cd, minor(dev)); 212 if (sc == NULL) { 213 cf = malloc(sizeof(*cf), M_DEVBUF, M_WAITOK); 214 cf->cf_name = fss_cd.cd_name; 215 cf->cf_atname = fss_cd.cd_name; 216 cf->cf_unit = minor(dev); 217 cf->cf_fstate = FSTATE_STAR; 218 sc = device_private(config_attach_pseudo(cf)); 219 if (sc == NULL) { 220 mutex_exit(&fss_device_lock); 221 return ENOMEM; 222 } 223 sc->sc_state = FSS_IDLE; 224 } 225 226 mutex_enter(&sc->sc_slock); 227 228 sc->sc_flags |= mflag; 229 230 mutex_exit(&sc->sc_slock); 231 mutex_exit(&fss_device_lock); 232 233 return 0; 234 } 235 236 int 237 fss_close(dev_t dev, int flags, int mode, struct lwp *l) 238 { 239 int mflag, error; 240 cfdata_t cf; 241 struct fss_softc *sc = device_lookup_private(&fss_cd, minor(dev)); 242 243 mflag = (mode == S_IFCHR ? FSS_CDEV_OPEN : FSS_BDEV_OPEN); 244 error = 0; 245 246 mutex_enter(&fss_device_lock); 247 restart: 248 mutex_enter(&sc->sc_slock); 249 if ((sc->sc_flags & (FSS_CDEV_OPEN|FSS_BDEV_OPEN)) != mflag) { 250 sc->sc_flags &= ~mflag; 251 mutex_exit(&sc->sc_slock); 252 mutex_exit(&fss_device_lock); 253 return 0; 254 } 255 if (sc->sc_state != FSS_IDLE && 256 (sc->sc_uflags & FSS_UNCONFIG_ON_CLOSE) != 0) { 257 sc->sc_uflags &= ~FSS_UNCONFIG_ON_CLOSE; 258 mutex_exit(&sc->sc_slock); 259 error = fss_ioctl(dev, FSSIOCCLR, NULL, FWRITE, l); 260 goto restart; 261 } 262 if (sc->sc_state != FSS_IDLE) { 263 mutex_exit(&sc->sc_slock); 264 mutex_exit(&fss_device_lock); 265 return error; 266 } 267 268 KASSERT(sc->sc_state == FSS_IDLE); 269 KASSERT((sc->sc_flags & (FSS_CDEV_OPEN|FSS_BDEV_OPEN)) == mflag); 270 mutex_exit(&sc->sc_slock); 271 cf = device_cfdata(sc->sc_dev); 272 error = config_detach(sc->sc_dev, DETACH_QUIET); 273 if (! error) 274 free(cf, M_DEVBUF); 275 mutex_exit(&fss_device_lock); 276 277 return error; 278 } 279 280 void 281 fss_strategy(struct buf *bp) 282 { 283 const bool write = ((bp->b_flags & B_READ) != B_READ); 284 struct fss_softc *sc = device_lookup_private(&fss_cd, minor(bp->b_dev)); 285 286 mutex_enter(&sc->sc_slock); 287 288 if (write || sc->sc_state != FSS_ACTIVE) { 289 bp->b_error = (write ? EROFS : ENXIO); 290 goto done; 291 } 292 /* Check bounds for non-persistent snapshots. */ 293 if ((sc->sc_flags & FSS_PERSISTENT) == 0 && 294 bounds_check_with_mediasize(bp, DEV_BSIZE, 295 btodb(FSS_CLTOB(sc, sc->sc_clcount - 1) + sc->sc_clresid)) <= 0) 296 goto done; 297 298 bp->b_rawblkno = bp->b_blkno; 299 bufq_put(sc->sc_bufq, bp); 300 cv_signal(&sc->sc_work_cv); 301 302 mutex_exit(&sc->sc_slock); 303 return; 304 305 done: 306 mutex_exit(&sc->sc_slock); 307 bp->b_resid = bp->b_bcount; 308 biodone(bp); 309 } 310 311 int 312 fss_read(dev_t dev, struct uio *uio, int flags) 313 { 314 return physio(fss_strategy, NULL, dev, B_READ, minphys, uio); 315 } 316 317 int 318 fss_write(dev_t dev, struct uio *uio, int flags) 319 { 320 return physio(fss_strategy, NULL, dev, B_WRITE, minphys, uio); 321 } 322 323 int 324 fss_ioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l) 325 { 326 int error = 0; 327 struct fss_softc *sc = device_lookup_private(&fss_cd, minor(dev)); 328 struct fss_set _fss; 329 struct fss_set *fss = (struct fss_set *)data; 330 struct fss_set50 *fss50 = (struct fss_set50 *)data; 331 struct fss_get *fsg = (struct fss_get *)data; 332 #ifndef _LP64 333 struct fss_get50 *fsg50 = (struct fss_get50 *)data; 334 #endif 335 336 switch (cmd) { 337 case FSSIOCSET50: 338 fss = &_fss; 339 fss->fss_mount = fss50->fss_mount; 340 fss->fss_bstore = fss50->fss_bstore; 341 fss->fss_csize = fss50->fss_csize; 342 fss->fss_flags = 0; 343 /* Fall through */ 344 case FSSIOCSET: 345 mutex_enter(&sc->sc_slock); 346 if ((flag & FWRITE) == 0) 347 error = EPERM; 348 if (error == 0 && sc->sc_state != FSS_IDLE) { 349 error = EBUSY; 350 } else { 351 sc->sc_state = FSS_CREATING; 352 copyinstr(fss->fss_mount, sc->sc_mntname, 353 sizeof(sc->sc_mntname), NULL); 354 memset(&sc->sc_time, 0, sizeof(sc->sc_time)); 355 sc->sc_clshift = 0; 356 } 357 mutex_exit(&sc->sc_slock); 358 if (error) 359 break; 360 361 /* 362 * Serialize snapshot creation. 363 */ 364 mutex_enter(&fss_device_lock); 365 while (fss_creating) { 366 error = cv_wait_sig(&fss_device_cv, &fss_device_lock); 367 if (error) { 368 mutex_enter(&sc->sc_slock); 369 KASSERT(sc->sc_state == FSS_CREATING); 370 sc->sc_state = FSS_IDLE; 371 mutex_exit(&sc->sc_slock); 372 mutex_exit(&fss_device_lock); 373 break; 374 } 375 } 376 fss_creating = true; 377 mutex_exit(&fss_device_lock); 378 379 error = fss_create_snapshot(sc, fss, l); 380 mutex_enter(&sc->sc_slock); 381 if (error == 0) { 382 KASSERT(sc->sc_state == FSS_ACTIVE); 383 sc->sc_uflags = fss->fss_flags; 384 } else { 385 KASSERT(sc->sc_state == FSS_CREATING); 386 sc->sc_state = FSS_IDLE; 387 } 388 mutex_exit(&sc->sc_slock); 389 390 mutex_enter(&fss_device_lock); 391 fss_creating = false; 392 cv_broadcast(&fss_device_cv); 393 mutex_exit(&fss_device_lock); 394 395 break; 396 397 case FSSIOCCLR: 398 mutex_enter(&sc->sc_slock); 399 if ((flag & FWRITE) == 0) { 400 error = EPERM; 401 } else if (sc->sc_state != FSS_ACTIVE && 402 sc->sc_state != FSS_ERROR) { 403 error = EBUSY; 404 } else { 405 sc->sc_state = FSS_DESTROYING; 406 } 407 mutex_exit(&sc->sc_slock); 408 if (error) 409 break; 410 411 error = fss_delete_snapshot(sc, l); 412 mutex_enter(&sc->sc_slock); 413 if (error) 414 fss_error(sc, "Failed to delete snapshot"); 415 else 416 KASSERT(sc->sc_state == FSS_IDLE); 417 mutex_exit(&sc->sc_slock); 418 break; 419 420 #ifndef _LP64 421 case FSSIOCGET50: 422 mutex_enter(&sc->sc_slock); 423 if (sc->sc_state == FSS_IDLE) { 424 error = ENXIO; 425 } else if ((sc->sc_flags & FSS_PERSISTENT) == 0) { 426 memcpy(fsg50->fsg_mount, sc->sc_mntname, MNAMELEN); 427 fsg50->fsg_csize = FSS_CLSIZE(sc); 428 timeval_to_timeval50(&sc->sc_time, &fsg50->fsg_time); 429 fsg50->fsg_mount_size = sc->sc_clcount; 430 fsg50->fsg_bs_size = sc->sc_clnext; 431 error = 0; 432 } else { 433 memcpy(fsg50->fsg_mount, sc->sc_mntname, MNAMELEN); 434 fsg50->fsg_csize = 0; 435 timeval_to_timeval50(&sc->sc_time, &fsg50->fsg_time); 436 fsg50->fsg_mount_size = 0; 437 fsg50->fsg_bs_size = 0; 438 error = 0; 439 } 440 mutex_exit(&sc->sc_slock); 441 break; 442 #endif /* _LP64 */ 443 444 case FSSIOCGET: 445 mutex_enter(&sc->sc_slock); 446 if (sc->sc_state == FSS_IDLE) { 447 error = ENXIO; 448 } else if ((sc->sc_flags & FSS_PERSISTENT) == 0) { 449 memcpy(fsg->fsg_mount, sc->sc_mntname, MNAMELEN); 450 fsg->fsg_csize = FSS_CLSIZE(sc); 451 fsg->fsg_time = sc->sc_time; 452 fsg->fsg_mount_size = sc->sc_clcount; 453 fsg->fsg_bs_size = sc->sc_clnext; 454 error = 0; 455 } else { 456 memcpy(fsg->fsg_mount, sc->sc_mntname, MNAMELEN); 457 fsg->fsg_csize = 0; 458 fsg->fsg_time = sc->sc_time; 459 fsg->fsg_mount_size = 0; 460 fsg->fsg_bs_size = 0; 461 error = 0; 462 } 463 mutex_exit(&sc->sc_slock); 464 break; 465 466 case FSSIOFSET: 467 mutex_enter(&sc->sc_slock); 468 sc->sc_uflags = *(int *)data; 469 mutex_exit(&sc->sc_slock); 470 error = 0; 471 break; 472 473 case FSSIOFGET: 474 mutex_enter(&sc->sc_slock); 475 *(int *)data = sc->sc_uflags; 476 mutex_exit(&sc->sc_slock); 477 error = 0; 478 break; 479 480 default: 481 error = EINVAL; 482 break; 483 } 484 485 return error; 486 } 487 488 int 489 fss_size(dev_t dev) 490 { 491 return -1; 492 } 493 494 int 495 fss_dump(dev_t dev, daddr_t blkno, void *va, 496 size_t size) 497 { 498 return EROFS; 499 } 500 501 /* 502 * An error occurred reading or writing the snapshot or backing store. 503 * If it is the first error log to console and disestablish cow handler. 504 * The caller holds the mutex. 505 */ 506 static inline void 507 fss_error(struct fss_softc *sc, const char *msg) 508 { 509 510 KASSERT(mutex_owned(&sc->sc_slock)); 511 512 if (sc->sc_state == FSS_ERROR) 513 return; 514 515 aprint_error_dev(sc->sc_dev, "snapshot invalid: %s\n", msg); 516 if ((sc->sc_flags & FSS_PERSISTENT) == 0) { 517 mutex_exit(&sc->sc_slock); 518 fscow_disestablish(sc->sc_mount, fss_copy_on_write, sc); 519 mutex_enter(&sc->sc_slock); 520 } 521 sc->sc_state = FSS_ERROR; 522 } 523 524 /* 525 * Allocate the variable sized parts of the softc and 526 * fork the kernel thread. 527 * 528 * The fields sc_clcount, sc_clshift, sc_cache_size and sc_indir_size 529 * must be initialized. 530 */ 531 static int 532 fss_softc_alloc(struct fss_softc *sc) 533 { 534 int i, error; 535 536 if ((sc->sc_flags & FSS_PERSISTENT) == 0) { 537 sc->sc_copied = 538 kmem_zalloc(howmany(sc->sc_clcount, NBBY), KM_SLEEP); 539 sc->sc_cache = kmem_alloc(sc->sc_cache_size * 540 sizeof(struct fss_cache), KM_SLEEP); 541 for (i = 0; i < sc->sc_cache_size; i++) { 542 sc->sc_cache[i].fc_type = FSS_CACHE_FREE; 543 sc->sc_cache[i].fc_data = 544 kmem_alloc(FSS_CLSIZE(sc), KM_SLEEP); 545 cv_init(&sc->sc_cache[i].fc_state_cv, "cowwait1"); 546 } 547 548 sc->sc_indir_valid = 549 kmem_zalloc(howmany(sc->sc_indir_size, NBBY), KM_SLEEP); 550 sc->sc_indir_data = kmem_zalloc(FSS_CLSIZE(sc), KM_SLEEP); 551 } else { 552 sc->sc_copied = NULL; 553 sc->sc_cache = NULL; 554 sc->sc_indir_valid = NULL; 555 sc->sc_indir_data = NULL; 556 } 557 558 sc->sc_flags |= FSS_BS_THREAD; 559 if ((error = kthread_create(PRI_BIO, KTHREAD_MUSTJOIN, NULL, 560 fss_bs_thread, sc, &sc->sc_bs_lwp, 561 "%s", device_xname(sc->sc_dev))) != 0) { 562 sc->sc_flags &= ~FSS_BS_THREAD; 563 return error; 564 } 565 566 disk_attach(sc->sc_dkdev); 567 568 return 0; 569 } 570 571 /* 572 * Free the variable sized parts of the softc. 573 */ 574 static void 575 fss_softc_free(struct fss_softc *sc) 576 { 577 int i; 578 579 if ((sc->sc_flags & FSS_BS_THREAD) != 0) { 580 mutex_enter(&sc->sc_slock); 581 sc->sc_flags &= ~FSS_BS_THREAD; 582 cv_signal(&sc->sc_work_cv); 583 mutex_exit(&sc->sc_slock); 584 kthread_join(sc->sc_bs_lwp); 585 586 disk_detach(sc->sc_dkdev); 587 } 588 589 if (sc->sc_copied != NULL) 590 kmem_free(sc->sc_copied, howmany(sc->sc_clcount, NBBY)); 591 sc->sc_copied = NULL; 592 593 if (sc->sc_cache != NULL) { 594 for (i = 0; i < sc->sc_cache_size; i++) 595 if (sc->sc_cache[i].fc_data != NULL) { 596 cv_destroy(&sc->sc_cache[i].fc_state_cv); 597 kmem_free(sc->sc_cache[i].fc_data, 598 FSS_CLSIZE(sc)); 599 } 600 kmem_free(sc->sc_cache, 601 sc->sc_cache_size*sizeof(struct fss_cache)); 602 } 603 sc->sc_cache = NULL; 604 605 if (sc->sc_indir_valid != NULL) 606 kmem_free(sc->sc_indir_valid, howmany(sc->sc_indir_size, NBBY)); 607 sc->sc_indir_valid = NULL; 608 609 if (sc->sc_indir_data != NULL) 610 kmem_free(sc->sc_indir_data, FSS_CLSIZE(sc)); 611 sc->sc_indir_data = NULL; 612 } 613 614 /* 615 * Set all active snapshots on this file system into ERROR state. 616 */ 617 static void 618 fss_unmount_hook(struct mount *mp) 619 { 620 int i; 621 struct fss_softc *sc; 622 623 mutex_enter(&fss_device_lock); 624 for (i = 0; i < fss_cd.cd_ndevs; i++) { 625 if ((sc = device_lookup_private(&fss_cd, i)) == NULL) 626 continue; 627 mutex_enter(&sc->sc_slock); 628 if (sc->sc_state != FSS_IDLE && sc->sc_mount == mp) 629 fss_error(sc, "forced by unmount"); 630 mutex_exit(&sc->sc_slock); 631 } 632 mutex_exit(&fss_device_lock); 633 } 634 635 /* 636 * A buffer is written to the snapshotted block device. Copy to 637 * backing store if needed. 638 */ 639 static int 640 fss_copy_on_write(void *v, struct buf *bp, bool data_valid) 641 { 642 int error; 643 u_int32_t cl, ch, c; 644 struct fss_softc *sc = v; 645 646 mutex_enter(&sc->sc_slock); 647 if (sc->sc_state != FSS_ACTIVE) { 648 mutex_exit(&sc->sc_slock); 649 return 0; 650 } 651 652 cl = FSS_BTOCL(sc, dbtob(bp->b_blkno)); 653 ch = FSS_BTOCL(sc, dbtob(bp->b_blkno)+bp->b_bcount-1); 654 error = 0; 655 if (curlwp == uvm.pagedaemon_lwp) { 656 for (c = cl; c <= ch; c++) 657 if (isclr(sc->sc_copied, c)) { 658 error = ENOMEM; 659 break; 660 } 661 } 662 mutex_exit(&sc->sc_slock); 663 664 if (error == 0) 665 for (c = cl; c <= ch; c++) { 666 error = fss_read_cluster(sc, c); 667 if (error) 668 break; 669 } 670 671 return error; 672 } 673 674 /* 675 * Lookup and open needed files. 676 * 677 * For file system internal snapshot initializes sc_mntname, sc_mount, 678 * sc_bs_vp and sc_time. 679 * 680 * Otherwise returns dev and size of the underlying block device. 681 * Initializes sc_mntname, sc_mount, sc_bdev, sc_bs_vp and sc_mount 682 */ 683 static int 684 fss_create_files(struct fss_softc *sc, struct fss_set *fss, 685 off_t *bsize, struct lwp *l) 686 { 687 int error, bits, fsbsize; 688 uint64_t numsec; 689 unsigned int secsize; 690 struct timespec ts; 691 /* nd -> nd2 to reduce mistakes while updating only some namei calls */ 692 struct pathbuf *pb2; 693 struct nameidata nd2; 694 struct vnode *vp; 695 696 /* 697 * Get the mounted file system. 698 */ 699 700 error = namei_simple_user(fss->fss_mount, 701 NSM_FOLLOW_NOEMULROOT, &vp); 702 if (error != 0) 703 return error; 704 705 if ((vp->v_vflag & VV_ROOT) != VV_ROOT) { 706 vrele(vp); 707 return EINVAL; 708 } 709 710 sc->sc_mount = vp->v_mount; 711 memcpy(sc->sc_mntname, sc->sc_mount->mnt_stat.f_mntonname, MNAMELEN); 712 713 vrele(vp); 714 715 /* 716 * Check for file system internal snapshot. 717 */ 718 719 error = namei_simple_user(fss->fss_bstore, 720 NSM_FOLLOW_NOEMULROOT, &vp); 721 if (error != 0) 722 return error; 723 724 if (vp->v_type == VREG && vp->v_mount == sc->sc_mount) { 725 sc->sc_flags |= FSS_PERSISTENT; 726 sc->sc_bs_vp = vp; 727 728 fsbsize = sc->sc_bs_vp->v_mount->mnt_stat.f_iosize; 729 bits = sizeof(sc->sc_bs_bshift)*NBBY; 730 for (sc->sc_bs_bshift = 1; sc->sc_bs_bshift < bits; 731 sc->sc_bs_bshift++) 732 if (FSS_FSBSIZE(sc) == fsbsize) 733 break; 734 if (sc->sc_bs_bshift >= bits) 735 return EINVAL; 736 737 sc->sc_bs_bmask = FSS_FSBSIZE(sc)-1; 738 sc->sc_clshift = 0; 739 740 if ((fss->fss_flags & FSS_UNLINK_ON_CREATE) != 0) { 741 error = do_sys_unlink(fss->fss_bstore, UIO_USERSPACE); 742 if (error) 743 return error; 744 } 745 error = vn_lock(vp, LK_EXCLUSIVE); 746 if (error != 0) 747 return error; 748 error = VFS_SNAPSHOT(sc->sc_mount, sc->sc_bs_vp, &ts); 749 TIMESPEC_TO_TIMEVAL(&sc->sc_time, &ts); 750 751 VOP_UNLOCK(sc->sc_bs_vp); 752 753 return error; 754 } 755 vrele(vp); 756 757 /* 758 * Get the block device it is mounted on and its size. 759 */ 760 761 error = spec_node_lookup_by_mount(sc->sc_mount, &vp); 762 if (error) 763 return error; 764 sc->sc_bdev = vp->v_rdev; 765 766 error = getdisksize(vp, &numsec, &secsize); 767 vrele(vp); 768 if (error) 769 return error; 770 771 *bsize = (off_t)numsec*secsize; 772 773 /* 774 * Get the backing store 775 */ 776 777 error = pathbuf_copyin(fss->fss_bstore, &pb2); 778 if (error) { 779 return error; 780 } 781 NDINIT(&nd2, LOOKUP, FOLLOW, pb2); 782 if ((error = vn_open(&nd2, FREAD|FWRITE, 0)) != 0) { 783 pathbuf_destroy(pb2); 784 return error; 785 } 786 VOP_UNLOCK(nd2.ni_vp); 787 788 sc->sc_bs_vp = nd2.ni_vp; 789 790 if (nd2.ni_vp->v_type != VREG && nd2.ni_vp->v_type != VCHR) { 791 pathbuf_destroy(pb2); 792 return EINVAL; 793 } 794 pathbuf_destroy(pb2); 795 796 if ((fss->fss_flags & FSS_UNLINK_ON_CREATE) != 0) { 797 error = do_sys_unlink(fss->fss_bstore, UIO_USERSPACE); 798 if (error) 799 return error; 800 } 801 if (sc->sc_bs_vp->v_type == VREG) { 802 fsbsize = sc->sc_bs_vp->v_mount->mnt_stat.f_iosize; 803 if (fsbsize & (fsbsize-1)) /* No power of two */ 804 return EINVAL; 805 for (sc->sc_bs_bshift = 1; sc->sc_bs_bshift < 32; 806 sc->sc_bs_bshift++) 807 if (FSS_FSBSIZE(sc) == fsbsize) 808 break; 809 if (sc->sc_bs_bshift >= 32) 810 return EINVAL; 811 sc->sc_bs_bmask = FSS_FSBSIZE(sc)-1; 812 } else { 813 sc->sc_bs_bshift = DEV_BSHIFT; 814 sc->sc_bs_bmask = FSS_FSBSIZE(sc)-1; 815 } 816 817 return 0; 818 } 819 820 /* 821 * Create a snapshot. 822 */ 823 static int 824 fss_create_snapshot(struct fss_softc *sc, struct fss_set *fss, struct lwp *l) 825 { 826 int len, error; 827 u_int32_t csize; 828 off_t bsize; 829 830 bsize = 0; /* XXX gcc */ 831 832 /* 833 * Open needed files. 834 */ 835 if ((error = fss_create_files(sc, fss, &bsize, l)) != 0) 836 goto bad; 837 838 if (sc->sc_flags & FSS_PERSISTENT) { 839 fss_softc_alloc(sc); 840 mutex_enter(&sc->sc_slock); 841 sc->sc_state = FSS_ACTIVE; 842 mutex_exit(&sc->sc_slock); 843 return 0; 844 } 845 846 /* 847 * Set cluster size. Must be a power of two and 848 * a multiple of backing store block size. 849 */ 850 if (fss->fss_csize <= 0) 851 csize = MAXPHYS; 852 else 853 csize = fss->fss_csize; 854 if (bsize/csize > FSS_CLUSTER_MAX) 855 csize = bsize/FSS_CLUSTER_MAX+1; 856 857 for (sc->sc_clshift = sc->sc_bs_bshift; sc->sc_clshift < 32; 858 sc->sc_clshift++) 859 if (FSS_CLSIZE(sc) >= csize) 860 break; 861 if (sc->sc_clshift >= 32) { 862 error = EINVAL; 863 goto bad; 864 } 865 sc->sc_clmask = FSS_CLSIZE(sc)-1; 866 867 /* 868 * Set number of cache slots. 869 */ 870 if (FSS_CLSIZE(sc) <= 8192) 871 sc->sc_cache_size = 32; 872 else if (FSS_CLSIZE(sc) <= 65536) 873 sc->sc_cache_size = 8; 874 else 875 sc->sc_cache_size = 4; 876 877 /* 878 * Set number of clusters and size of last cluster. 879 */ 880 sc->sc_clcount = FSS_BTOCL(sc, bsize-1)+1; 881 sc->sc_clresid = FSS_CLOFF(sc, bsize-1)+1; 882 883 /* 884 * Set size of indirect table. 885 */ 886 len = sc->sc_clcount*sizeof(u_int32_t); 887 sc->sc_indir_size = FSS_BTOCL(sc, len)+1; 888 sc->sc_clnext = sc->sc_indir_size; 889 sc->sc_indir_cur = 0; 890 891 if ((error = fss_softc_alloc(sc)) != 0) 892 goto bad; 893 894 /* 895 * Activate the snapshot. 896 */ 897 898 if ((error = vfs_suspend(sc->sc_mount, 0)) != 0) 899 goto bad; 900 901 microtime(&sc->sc_time); 902 903 vrele_flush(sc->sc_mount); 904 error = VFS_SYNC(sc->sc_mount, MNT_WAIT, curlwp->l_cred); 905 if (error == 0) 906 error = fscow_establish(sc->sc_mount, fss_copy_on_write, sc); 907 if (error == 0) { 908 mutex_enter(&sc->sc_slock); 909 sc->sc_state = FSS_ACTIVE; 910 mutex_exit(&sc->sc_slock); 911 } 912 913 vfs_resume(sc->sc_mount); 914 915 if (error != 0) 916 goto bad; 917 918 aprint_debug_dev(sc->sc_dev, "%s snapshot active\n", sc->sc_mntname); 919 aprint_debug_dev(sc->sc_dev, 920 "%u clusters of %u, %u cache slots, %u indir clusters\n", 921 sc->sc_clcount, FSS_CLSIZE(sc), 922 sc->sc_cache_size, sc->sc_indir_size); 923 924 return 0; 925 926 bad: 927 fss_softc_free(sc); 928 if (sc->sc_bs_vp != NULL) { 929 if (sc->sc_flags & FSS_PERSISTENT) 930 vrele(sc->sc_bs_vp); 931 else 932 vn_close(sc->sc_bs_vp, FREAD|FWRITE, l->l_cred); 933 } 934 sc->sc_bs_vp = NULL; 935 936 return error; 937 } 938 939 /* 940 * Delete a snapshot. 941 */ 942 static int 943 fss_delete_snapshot(struct fss_softc *sc, struct lwp *l) 944 { 945 946 mutex_enter(&sc->sc_slock); 947 if ((sc->sc_flags & FSS_PERSISTENT) == 0 && sc->sc_state != FSS_ERROR) { 948 mutex_exit(&sc->sc_slock); 949 fscow_disestablish(sc->sc_mount, fss_copy_on_write, sc); 950 } else { 951 mutex_exit(&sc->sc_slock); 952 } 953 954 fss_softc_free(sc); 955 if (sc->sc_flags & FSS_PERSISTENT) 956 vrele(sc->sc_bs_vp); 957 else 958 vn_close(sc->sc_bs_vp, FREAD|FWRITE, l->l_cred); 959 960 mutex_enter(&sc->sc_slock); 961 sc->sc_state = FSS_IDLE; 962 sc->sc_mount = NULL; 963 sc->sc_bdev = NODEV; 964 sc->sc_bs_vp = NULL; 965 sc->sc_flags &= ~FSS_PERSISTENT; 966 mutex_exit(&sc->sc_slock); 967 968 return 0; 969 } 970 971 /* 972 * Read a cluster from the snapshotted block device to the cache. 973 */ 974 static int 975 fss_read_cluster(struct fss_softc *sc, u_int32_t cl) 976 { 977 int error, todo, offset, len; 978 daddr_t dblk; 979 struct buf *bp, *mbp; 980 struct fss_cache *scp, *scl; 981 982 /* 983 * Get a free cache slot. 984 */ 985 scl = sc->sc_cache+sc->sc_cache_size; 986 987 mutex_enter(&sc->sc_slock); 988 989 restart: 990 if (isset(sc->sc_copied, cl) || sc->sc_state != FSS_ACTIVE) { 991 mutex_exit(&sc->sc_slock); 992 return 0; 993 } 994 995 for (scp = sc->sc_cache; scp < scl; scp++) 996 if (scp->fc_cluster == cl) { 997 if (scp->fc_type == FSS_CACHE_VALID) { 998 mutex_exit(&sc->sc_slock); 999 return 0; 1000 } else if (scp->fc_type == FSS_CACHE_BUSY) { 1001 cv_wait(&scp->fc_state_cv, &sc->sc_slock); 1002 goto restart; 1003 } 1004 } 1005 1006 for (scp = sc->sc_cache; scp < scl; scp++) 1007 if (scp->fc_type == FSS_CACHE_FREE) { 1008 scp->fc_type = FSS_CACHE_BUSY; 1009 scp->fc_cluster = cl; 1010 break; 1011 } 1012 if (scp >= scl) { 1013 cv_wait(&sc->sc_cache_cv, &sc->sc_slock); 1014 goto restart; 1015 } 1016 1017 mutex_exit(&sc->sc_slock); 1018 1019 /* 1020 * Start the read. 1021 */ 1022 dblk = btodb(FSS_CLTOB(sc, cl)); 1023 if (cl == sc->sc_clcount-1) { 1024 todo = sc->sc_clresid; 1025 memset((char *)scp->fc_data + todo, 0, FSS_CLSIZE(sc) - todo); 1026 } else 1027 todo = FSS_CLSIZE(sc); 1028 offset = 0; 1029 mbp = getiobuf(NULL, true); 1030 mbp->b_bufsize = todo; 1031 mbp->b_data = scp->fc_data; 1032 mbp->b_resid = mbp->b_bcount = todo; 1033 mbp->b_flags = B_READ; 1034 mbp->b_cflags = BC_BUSY; 1035 mbp->b_dev = sc->sc_bdev; 1036 while (todo > 0) { 1037 len = todo; 1038 if (len > MAXPHYS) 1039 len = MAXPHYS; 1040 if (btodb(FSS_CLTOB(sc, cl)) == dblk && len == todo) 1041 bp = mbp; 1042 else { 1043 bp = getiobuf(NULL, true); 1044 nestiobuf_setup(mbp, bp, offset, len); 1045 } 1046 bp->b_lblkno = 0; 1047 bp->b_blkno = dblk; 1048 bdev_strategy(bp); 1049 dblk += btodb(len); 1050 offset += len; 1051 todo -= len; 1052 } 1053 error = biowait(mbp); 1054 if (error == 0 && mbp->b_resid != 0) 1055 error = EIO; 1056 putiobuf(mbp); 1057 1058 mutex_enter(&sc->sc_slock); 1059 scp->fc_type = (error ? FSS_CACHE_FREE : FSS_CACHE_VALID); 1060 cv_broadcast(&scp->fc_state_cv); 1061 if (error == 0) { 1062 setbit(sc->sc_copied, scp->fc_cluster); 1063 cv_signal(&sc->sc_work_cv); 1064 } 1065 mutex_exit(&sc->sc_slock); 1066 1067 return error; 1068 } 1069 1070 /* 1071 * Read/write clusters from/to backing store. 1072 * For persistent snapshots must be called with cl == 0. off is the 1073 * offset into the snapshot. 1074 */ 1075 static int 1076 fss_bs_io(struct fss_softc *sc, fss_io_type rw, 1077 u_int32_t cl, off_t off, int len, void *data, size_t *resid) 1078 { 1079 int error; 1080 1081 off += FSS_CLTOB(sc, cl); 1082 1083 vn_lock(sc->sc_bs_vp, LK_EXCLUSIVE|LK_RETRY); 1084 1085 error = vn_rdwr((rw == FSS_READ ? UIO_READ : UIO_WRITE), sc->sc_bs_vp, 1086 data, len, off, UIO_SYSSPACE, 1087 IO_ADV_ENCODE(POSIX_FADV_NOREUSE) | IO_NODELOCKED, 1088 sc->sc_bs_lwp->l_cred, resid, NULL); 1089 if (error == 0) { 1090 mutex_enter(sc->sc_bs_vp->v_interlock); 1091 error = VOP_PUTPAGES(sc->sc_bs_vp, trunc_page(off), 1092 round_page(off+len), PGO_CLEANIT | PGO_FREE | PGO_SYNCIO); 1093 } 1094 1095 VOP_UNLOCK(sc->sc_bs_vp); 1096 1097 return error; 1098 } 1099 1100 /* 1101 * Get a pointer to the indirect slot for this cluster. 1102 */ 1103 static u_int32_t * 1104 fss_bs_indir(struct fss_softc *sc, u_int32_t cl) 1105 { 1106 u_int32_t icl; 1107 int ioff; 1108 1109 icl = cl/(FSS_CLSIZE(sc)/sizeof(u_int32_t)); 1110 ioff = cl%(FSS_CLSIZE(sc)/sizeof(u_int32_t)); 1111 1112 if (sc->sc_indir_cur == icl) 1113 return &sc->sc_indir_data[ioff]; 1114 1115 if (sc->sc_indir_dirty) { 1116 if (fss_bs_io(sc, FSS_WRITE, sc->sc_indir_cur, 0, 1117 FSS_CLSIZE(sc), (void *)sc->sc_indir_data, NULL) != 0) 1118 return NULL; 1119 setbit(sc->sc_indir_valid, sc->sc_indir_cur); 1120 } 1121 1122 sc->sc_indir_dirty = 0; 1123 sc->sc_indir_cur = icl; 1124 1125 if (isset(sc->sc_indir_valid, sc->sc_indir_cur)) { 1126 if (fss_bs_io(sc, FSS_READ, sc->sc_indir_cur, 0, 1127 FSS_CLSIZE(sc), (void *)sc->sc_indir_data, NULL) != 0) 1128 return NULL; 1129 } else 1130 memset(sc->sc_indir_data, 0, FSS_CLSIZE(sc)); 1131 1132 return &sc->sc_indir_data[ioff]; 1133 } 1134 1135 /* 1136 * The kernel thread (one for every active snapshot). 1137 * 1138 * After wakeup it cleans the cache and runs the I/O requests. 1139 */ 1140 static void 1141 fss_bs_thread(void *arg) 1142 { 1143 bool thread_idle, is_valid; 1144 int error, i, todo, len, crotor, is_read; 1145 long off; 1146 char *addr; 1147 u_int32_t c, cl, ch, *indirp; 1148 size_t resid; 1149 struct buf *bp, *nbp; 1150 struct fss_softc *sc; 1151 struct fss_cache *scp, *scl; 1152 1153 sc = arg; 1154 scl = sc->sc_cache+sc->sc_cache_size; 1155 crotor = 0; 1156 thread_idle = false; 1157 1158 mutex_enter(&sc->sc_slock); 1159 1160 for (;;) { 1161 if (thread_idle) 1162 cv_wait(&sc->sc_work_cv, &sc->sc_slock); 1163 thread_idle = true; 1164 if ((sc->sc_flags & FSS_BS_THREAD) == 0) { 1165 mutex_exit(&sc->sc_slock); 1166 kthread_exit(0); 1167 } 1168 1169 /* 1170 * Process I/O requests (persistent) 1171 */ 1172 1173 if (sc->sc_flags & FSS_PERSISTENT) { 1174 if ((bp = bufq_get(sc->sc_bufq)) == NULL) 1175 continue; 1176 is_valid = (sc->sc_state == FSS_ACTIVE); 1177 is_read = (bp->b_flags & B_READ); 1178 thread_idle = false; 1179 mutex_exit(&sc->sc_slock); 1180 1181 if (is_valid) { 1182 disk_busy(sc->sc_dkdev); 1183 error = fss_bs_io(sc, FSS_READ, 0, 1184 dbtob(bp->b_blkno), bp->b_bcount, 1185 bp->b_data, &resid); 1186 if (error) 1187 resid = bp->b_bcount; 1188 disk_unbusy(sc->sc_dkdev, 1189 (error ? 0 : bp->b_bcount), is_read); 1190 } else { 1191 error = ENXIO; 1192 resid = bp->b_bcount; 1193 } 1194 1195 bp->b_error = error; 1196 bp->b_resid = resid; 1197 biodone(bp); 1198 1199 mutex_enter(&sc->sc_slock); 1200 continue; 1201 } 1202 1203 /* 1204 * Clean the cache 1205 */ 1206 for (i = 0; i < sc->sc_cache_size; i++) { 1207 crotor = (crotor + 1) % sc->sc_cache_size; 1208 scp = sc->sc_cache + crotor; 1209 if (scp->fc_type != FSS_CACHE_VALID) 1210 continue; 1211 mutex_exit(&sc->sc_slock); 1212 1213 thread_idle = false; 1214 indirp = fss_bs_indir(sc, scp->fc_cluster); 1215 if (indirp != NULL) { 1216 error = fss_bs_io(sc, FSS_WRITE, sc->sc_clnext, 1217 0, FSS_CLSIZE(sc), scp->fc_data, NULL); 1218 } else 1219 error = EIO; 1220 1221 mutex_enter(&sc->sc_slock); 1222 if (error == 0) { 1223 *indirp = sc->sc_clnext++; 1224 sc->sc_indir_dirty = 1; 1225 } else 1226 fss_error(sc, "write error on backing store"); 1227 1228 scp->fc_type = FSS_CACHE_FREE; 1229 cv_broadcast(&sc->sc_cache_cv); 1230 break; 1231 } 1232 1233 /* 1234 * Process I/O requests 1235 */ 1236 if ((bp = bufq_get(sc->sc_bufq)) == NULL) 1237 continue; 1238 is_valid = (sc->sc_state == FSS_ACTIVE); 1239 is_read = (bp->b_flags & B_READ); 1240 thread_idle = false; 1241 1242 if (!is_valid) { 1243 mutex_exit(&sc->sc_slock); 1244 1245 bp->b_error = ENXIO; 1246 bp->b_resid = bp->b_bcount; 1247 biodone(bp); 1248 1249 mutex_enter(&sc->sc_slock); 1250 continue; 1251 } 1252 1253 disk_busy(sc->sc_dkdev); 1254 1255 /* 1256 * First read from the snapshotted block device unless 1257 * this request is completely covered by backing store. 1258 */ 1259 1260 cl = FSS_BTOCL(sc, dbtob(bp->b_blkno)); 1261 off = FSS_CLOFF(sc, dbtob(bp->b_blkno)); 1262 ch = FSS_BTOCL(sc, dbtob(bp->b_blkno)+bp->b_bcount-1); 1263 error = 0; 1264 bp->b_resid = 0; 1265 bp->b_error = 0; 1266 for (c = cl; c <= ch; c++) { 1267 if (isset(sc->sc_copied, c)) 1268 continue; 1269 mutex_exit(&sc->sc_slock); 1270 1271 /* Not on backing store, read from device. */ 1272 nbp = getiobuf(NULL, true); 1273 nbp->b_flags = B_READ; 1274 nbp->b_resid = nbp->b_bcount = bp->b_bcount; 1275 nbp->b_bufsize = bp->b_bcount; 1276 nbp->b_data = bp->b_data; 1277 nbp->b_blkno = bp->b_blkno; 1278 nbp->b_lblkno = 0; 1279 nbp->b_dev = sc->sc_bdev; 1280 SET(nbp->b_cflags, BC_BUSY); /* mark buffer busy */ 1281 1282 bdev_strategy(nbp); 1283 1284 error = biowait(nbp); 1285 if (error == 0 && nbp->b_resid != 0) 1286 error = EIO; 1287 if (error != 0) { 1288 bp->b_resid = bp->b_bcount; 1289 bp->b_error = nbp->b_error; 1290 disk_unbusy(sc->sc_dkdev, 0, is_read); 1291 biodone(bp); 1292 } 1293 putiobuf(nbp); 1294 1295 mutex_enter(&sc->sc_slock); 1296 break; 1297 } 1298 if (error) 1299 continue; 1300 1301 /* 1302 * Replace those parts that have been saved to backing store. 1303 */ 1304 1305 addr = bp->b_data; 1306 todo = bp->b_bcount; 1307 for (c = cl; c <= ch; c++, off = 0, todo -= len, addr += len) { 1308 len = FSS_CLSIZE(sc)-off; 1309 if (len > todo) 1310 len = todo; 1311 if (isclr(sc->sc_copied, c)) 1312 continue; 1313 mutex_exit(&sc->sc_slock); 1314 1315 indirp = fss_bs_indir(sc, c); 1316 if (indirp == NULL || *indirp == 0) { 1317 /* 1318 * Not on backing store. Either in cache 1319 * or hole in the snapshotted block device. 1320 */ 1321 1322 mutex_enter(&sc->sc_slock); 1323 for (scp = sc->sc_cache; scp < scl; scp++) 1324 if (scp->fc_type == FSS_CACHE_VALID && 1325 scp->fc_cluster == c) 1326 break; 1327 if (scp < scl) 1328 memcpy(addr, (char *)scp->fc_data+off, 1329 len); 1330 else 1331 memset(addr, 0, len); 1332 continue; 1333 } 1334 1335 /* 1336 * Read from backing store. 1337 */ 1338 error = fss_bs_io(sc, FSS_READ, 1339 *indirp, off, len, addr, NULL); 1340 1341 mutex_enter(&sc->sc_slock); 1342 if (error) { 1343 bp->b_resid = bp->b_bcount; 1344 bp->b_error = error; 1345 break; 1346 } 1347 } 1348 mutex_exit(&sc->sc_slock); 1349 1350 disk_unbusy(sc->sc_dkdev, (error ? 0 : bp->b_bcount), is_read); 1351 biodone(bp); 1352 1353 mutex_enter(&sc->sc_slock); 1354 } 1355 } 1356 1357 #ifdef _MODULE 1358 1359 #include <sys/module.h> 1360 1361 MODULE(MODULE_CLASS_DRIVER, fss, "bufq_fcfs"); 1362 CFDRIVER_DECL(fss, DV_DISK, NULL); 1363 1364 devmajor_t fss_bmajor = -1, fss_cmajor = -1; 1365 1366 static int 1367 fss_modcmd(modcmd_t cmd, void *arg) 1368 { 1369 int error = 0; 1370 1371 switch (cmd) { 1372 case MODULE_CMD_INIT: 1373 mutex_init(&fss_device_lock, MUTEX_DEFAULT, IPL_NONE); 1374 cv_init(&fss_device_cv, "snapwait"); 1375 error = config_cfdriver_attach(&fss_cd); 1376 if (error) { 1377 mutex_destroy(&fss_device_lock); 1378 break; 1379 } 1380 error = config_cfattach_attach(fss_cd.cd_name, &fss_ca); 1381 if (error) { 1382 config_cfdriver_detach(&fss_cd); 1383 mutex_destroy(&fss_device_lock); 1384 break; 1385 } 1386 error = devsw_attach(fss_cd.cd_name, 1387 &fss_bdevsw, &fss_bmajor, &fss_cdevsw, &fss_cmajor); 1388 1389 if (error) { 1390 config_cfattach_detach(fss_cd.cd_name, &fss_ca); 1391 config_cfdriver_detach(&fss_cd); 1392 mutex_destroy(&fss_device_lock); 1393 break; 1394 } 1395 break; 1396 1397 case MODULE_CMD_FINI: 1398 devsw_detach(&fss_bdevsw, &fss_cdevsw); 1399 error = config_cfattach_detach(fss_cd.cd_name, &fss_ca); 1400 if (error) { 1401 devsw_attach(fss_cd.cd_name, &fss_bdevsw, &fss_bmajor, 1402 &fss_cdevsw, &fss_cmajor); 1403 break; 1404 } 1405 error = config_cfdriver_detach(&fss_cd); 1406 if (error) { 1407 devsw_attach(fss_cd.cd_name, 1408 &fss_bdevsw, &fss_bmajor, &fss_cdevsw, &fss_cmajor); 1409 devsw_attach(fss_cd.cd_name, &fss_bdevsw, &fss_bmajor, 1410 &fss_cdevsw, &fss_cmajor); 1411 break; 1412 } 1413 cv_destroy(&fss_device_cv); 1414 mutex_destroy(&fss_device_lock); 1415 break; 1416 1417 default: 1418 error = ENOTTY; 1419 break; 1420 } 1421 1422 return error; 1423 } 1424 1425 #endif /* _MODULE */ 1426
Indexes created Wed Nov 11 00:26:22 UTC 2026