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sys/dev/fss.c
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1 /* $NetBSD: fss.c,v 1.60.4.3 2010/03/28 17:26:26 snj 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 1.60.4.3 2010/03/28 17:26:26 snj Exp $"); 40 41 #include <sys/param.h> 42 #include <sys/systm.h> 43 #include <sys/namei.h> 44 #include <sys/proc.h> 45 #include <sys/errno.h> 46 #include <sys/malloc.h> 47 #include <sys/buf.h> 48 #include <sys/ioctl.h> 49 #include <sys/disklabel.h> 50 #include <sys/device.h> 51 #include <sys/disk.h> 52 #include <sys/stat.h> 53 #include <sys/mount.h> 54 #include <sys/vnode.h> 55 #include <sys/file.h> 56 #include <sys/uio.h> 57 #include <sys/conf.h> 58 #include <sys/kthread.h> 59 #include <sys/fstrans.h> 60 #include <sys/simplelock.h> 61 62 #include <miscfs/specfs/specdev.h> 63 64 #include <dev/fssvar.h> 65 66 #include <uvm/uvm.h> 67 68 void fssattach(int); 69 70 dev_type_open(fss_open); 71 dev_type_close(fss_close); 72 dev_type_read(fss_read); 73 dev_type_write(fss_write); 74 dev_type_ioctl(fss_ioctl); 75 dev_type_strategy(fss_strategy); 76 dev_type_dump(fss_dump); 77 dev_type_size(fss_size); 78 79 static void fss_unmount_hook(struct mount *); 80 static int fss_copy_on_write(void *, struct buf *, bool); 81 static inline void fss_error(struct fss_softc *, const char *); 82 static int fss_create_files(struct fss_softc *, struct fss_set *, 83 off_t *, struct lwp *); 84 static int fss_create_snapshot(struct fss_softc *, struct fss_set *, 85 struct lwp *); 86 static int fss_delete_snapshot(struct fss_softc *, struct lwp *); 87 static int fss_softc_alloc(struct fss_softc *); 88 static void fss_softc_free(struct fss_softc *); 89 static int fss_read_cluster(struct fss_softc *, u_int32_t); 90 static void fss_bs_thread(void *); 91 static int fss_bs_io(struct fss_softc *, fss_io_type, 92 u_int32_t, off_t, int, void *); 93 static u_int32_t *fss_bs_indir(struct fss_softc *, u_int32_t); 94 95 static kmutex_t fss_device_lock; /* Protect all units. */ 96 static int fss_num_attached = 0; /* Number of attached devices. */ 97 static struct vfs_hooks fss_vfs_hooks = { 98 .vh_unmount = fss_unmount_hook 99 }; 100 101 const struct bdevsw fss_bdevsw = { 102 fss_open, fss_close, fss_strategy, fss_ioctl, 103 fss_dump, fss_size, D_DISK | D_MPSAFE 104 }; 105 106 const struct cdevsw fss_cdevsw = { 107 fss_open, fss_close, fss_read, fss_write, fss_ioctl, 108 nostop, notty, nopoll, nommap, nokqfilter, D_DISK | D_MPSAFE 109 }; 110 111 static int fss_match(device_t, cfdata_t, void *); 112 static void fss_attach(device_t, device_t, void *); 113 static int fss_detach(device_t, int); 114 115 CFATTACH_DECL_NEW(fss, sizeof(struct fss_softc), 116 fss_match, fss_attach, fss_detach, NULL); 117 extern struct cfdriver fss_cd; 118 119 void 120 fssattach(int num) 121 { 122 123 mutex_init(&fss_device_lock, MUTEX_DEFAULT, IPL_NONE); 124 if (config_cfattach_attach(fss_cd.cd_name, &fss_ca)) 125 aprint_error("%s: unable to register\n", fss_cd.cd_name); 126 } 127 128 static int 129 fss_match(device_t self, cfdata_t cfdata, void *aux) 130 { 131 return 1; 132 } 133 134 static void 135 fss_attach(device_t parent, device_t self, void *aux) 136 { 137 struct fss_softc *sc = device_private(self); 138 139 sc->sc_dev = self; 140 sc->sc_bdev = NODEV; 141 mutex_init(&sc->sc_slock, MUTEX_DEFAULT, IPL_NONE); 142 mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_NONE); 143 cv_init(&sc->sc_work_cv, "fssbs"); 144 cv_init(&sc->sc_cache_cv, "cowwait"); 145 bufq_alloc(&sc->sc_bufq, "fcfs", 0); 146 sc->sc_dkdev = malloc(sizeof(*sc->sc_dkdev), M_DEVBUF, M_WAITOK); 147 sc->sc_dkdev->dk_info = NULL; 148 disk_init(sc->sc_dkdev, device_xname(self), NULL); 149 if (!pmf_device_register(self, NULL, NULL)) 150 aprint_error_dev(self, "couldn't establish power handler\n"); 151 152 if (fss_num_attached++ == 0) 153 vfs_hooks_attach(&fss_vfs_hooks); 154 } 155 156 static int 157 fss_detach(device_t self, int flags) 158 { 159 struct fss_softc *sc = device_private(self); 160 161 if (sc->sc_flags & FSS_ACTIVE) 162 return EBUSY; 163 164 if (--fss_num_attached == 0) 165 vfs_hooks_detach(&fss_vfs_hooks); 166 167 pmf_device_deregister(self); 168 mutex_destroy(&sc->sc_slock); 169 mutex_destroy(&sc->sc_lock); 170 cv_destroy(&sc->sc_work_cv); 171 cv_destroy(&sc->sc_cache_cv); 172 bufq_drain(sc->sc_bufq); 173 bufq_free(sc->sc_bufq); 174 disk_destroy(sc->sc_dkdev); 175 free(sc->sc_dkdev, M_DEVBUF); 176 177 return 0; 178 } 179 180 int 181 fss_open(dev_t dev, int flags, int mode, struct lwp *l) 182 { 183 int mflag; 184 cfdata_t cf; 185 struct fss_softc *sc; 186 187 mflag = (mode == S_IFCHR ? FSS_CDEV_OPEN : FSS_BDEV_OPEN); 188 189 mutex_enter(&fss_device_lock); 190 191 sc = device_lookup_private(&fss_cd, minor(dev)); 192 if (sc == NULL) { 193 cf = malloc(sizeof(*cf), M_DEVBUF, M_WAITOK); 194 cf->cf_name = fss_cd.cd_name; 195 cf->cf_atname = fss_cd.cd_name; 196 cf->cf_unit = minor(dev); 197 cf->cf_fstate = FSTATE_STAR; 198 sc = device_private(config_attach_pseudo(cf)); 199 if (sc == NULL) 200 return ENOMEM; 201 } 202 203 mutex_enter(&sc->sc_slock); 204 205 sc->sc_flags |= mflag; 206 207 mutex_exit(&sc->sc_slock); 208 mutex_exit(&fss_device_lock); 209 210 return 0; 211 } 212 213 int 214 fss_close(dev_t dev, int flags, int mode, struct lwp *l) 215 { 216 int mflag, error; 217 cfdata_t cf; 218 struct fss_softc *sc = device_lookup_private(&fss_cd, minor(dev)); 219 220 mflag = (mode == S_IFCHR ? FSS_CDEV_OPEN : FSS_BDEV_OPEN); 221 error = 0; 222 223 restart: 224 mutex_enter(&sc->sc_slock); 225 if ((sc->sc_flags & (FSS_CDEV_OPEN|FSS_BDEV_OPEN)) != mflag) { 226 sc->sc_flags &= ~mflag; 227 mutex_exit(&sc->sc_slock); 228 return 0; 229 } 230 if ((sc->sc_flags & FSS_ACTIVE) != 0 && 231 (sc->sc_uflags & FSS_UNCONFIG_ON_CLOSE) != 0) { 232 sc->sc_uflags &= ~FSS_UNCONFIG_ON_CLOSE; 233 mutex_exit(&sc->sc_slock); 234 error = fss_ioctl(dev, FSSIOCCLR, NULL, FWRITE, l); 235 goto restart; 236 } 237 if ((sc->sc_flags & FSS_ACTIVE) != 0) { 238 mutex_exit(&sc->sc_slock); 239 return error; 240 } 241 if (! mutex_tryenter(&fss_device_lock)) { 242 mutex_exit(&sc->sc_slock); 243 goto restart; 244 } 245 246 KASSERT((sc->sc_flags & FSS_ACTIVE) == 0); 247 KASSERT((sc->sc_flags & (FSS_CDEV_OPEN|FSS_BDEV_OPEN)) == mflag); 248 mutex_exit(&sc->sc_slock); 249 cf = device_cfdata(sc->sc_dev); 250 error = config_detach(sc->sc_dev, DETACH_QUIET); 251 if (! error) 252 free(cf, M_DEVBUF); 253 mutex_exit(&fss_device_lock); 254 255 return error; 256 } 257 258 void 259 fss_strategy(struct buf *bp) 260 { 261 const bool write = ((bp->b_flags & B_READ) != B_READ); 262 struct fss_softc *sc = device_lookup_private(&fss_cd, minor(bp->b_dev)); 263 264 mutex_enter(&sc->sc_slock); 265 266 if (write || !FSS_ISVALID(sc)) { 267 268 mutex_exit(&sc->sc_slock); 269 270 bp->b_error = (write ? EROFS : ENXIO); 271 bp->b_resid = bp->b_bcount; 272 biodone(bp); 273 return; 274 } 275 276 bp->b_rawblkno = bp->b_blkno; 277 BUFQ_PUT(sc->sc_bufq, bp); 278 cv_signal(&sc->sc_work_cv); 279 280 mutex_exit(&sc->sc_slock); 281 } 282 283 int 284 fss_read(dev_t dev, struct uio *uio, int flags) 285 { 286 return physio(fss_strategy, NULL, dev, B_READ, minphys, uio); 287 } 288 289 int 290 fss_write(dev_t dev, struct uio *uio, int flags) 291 { 292 return physio(fss_strategy, NULL, dev, B_WRITE, minphys, uio); 293 } 294 295 int 296 fss_ioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l) 297 { 298 int error; 299 struct fss_softc *sc = device_lookup_private(&fss_cd, minor(dev)); 300 struct fss_set *fss = (struct fss_set *)data; 301 struct fss_get *fsg = (struct fss_get *)data; 302 303 switch (cmd) { 304 case FSSIOCSET: 305 mutex_enter(&sc->sc_lock); 306 if ((flag & FWRITE) == 0) 307 error = EPERM; 308 else if ((sc->sc_flags & FSS_ACTIVE) != 0) 309 error = EBUSY; 310 else 311 error = fss_create_snapshot(sc, fss, l); 312 mutex_exit(&sc->sc_lock); 313 break; 314 315 case FSSIOCCLR: 316 mutex_enter(&sc->sc_lock); 317 if ((flag & FWRITE) == 0) 318 error = EPERM; 319 else if ((sc->sc_flags & FSS_ACTIVE) == 0) 320 error = ENXIO; 321 else 322 error = fss_delete_snapshot(sc, l); 323 mutex_exit(&sc->sc_lock); 324 break; 325 326 case FSSIOCGET: 327 mutex_enter(&sc->sc_lock); 328 switch (sc->sc_flags & (FSS_PERSISTENT | FSS_ACTIVE)) { 329 case FSS_ACTIVE: 330 memcpy(fsg->fsg_mount, sc->sc_mntname, MNAMELEN); 331 fsg->fsg_csize = FSS_CLSIZE(sc); 332 fsg->fsg_time = sc->sc_time; 333 fsg->fsg_mount_size = sc->sc_clcount; 334 fsg->fsg_bs_size = sc->sc_clnext; 335 error = 0; 336 break; 337 case FSS_PERSISTENT | FSS_ACTIVE: 338 memcpy(fsg->fsg_mount, sc->sc_mntname, MNAMELEN); 339 fsg->fsg_csize = 0; 340 fsg->fsg_time = sc->sc_time; 341 fsg->fsg_mount_size = 0; 342 fsg->fsg_bs_size = 0; 343 error = 0; 344 break; 345 default: 346 error = ENXIO; 347 break; 348 } 349 mutex_exit(&sc->sc_lock); 350 break; 351 352 case FSSIOFSET: 353 mutex_enter(&sc->sc_slock); 354 sc->sc_uflags = *(int *)data; 355 mutex_exit(&sc->sc_slock); 356 error = 0; 357 break; 358 359 case FSSIOFGET: 360 mutex_enter(&sc->sc_slock); 361 *(int *)data = sc->sc_uflags; 362 mutex_exit(&sc->sc_slock); 363 error = 0; 364 break; 365 366 default: 367 error = EINVAL; 368 break; 369 } 370 371 return error; 372 } 373 374 int 375 fss_size(dev_t dev) 376 { 377 return -1; 378 } 379 380 int 381 fss_dump(dev_t dev, daddr_t blkno, void *va, 382 size_t size) 383 { 384 return EROFS; 385 } 386 387 /* 388 * An error occurred reading or writing the snapshot or backing store. 389 * If it is the first error log to console. 390 * The caller holds the mutex. 391 */ 392 static inline void 393 fss_error(struct fss_softc *sc, const char *msg) 394 { 395 396 if ((sc->sc_flags & (FSS_ACTIVE|FSS_ERROR)) == FSS_ACTIVE) 397 aprint_error_dev(sc->sc_dev, "snapshot invalid: %s\n", msg); 398 if ((sc->sc_flags & FSS_ACTIVE) == FSS_ACTIVE) 399 sc->sc_flags |= FSS_ERROR; 400 } 401 402 /* 403 * Allocate the variable sized parts of the softc and 404 * fork the kernel thread. 405 * 406 * The fields sc_clcount, sc_clshift, sc_cache_size and sc_indir_size 407 * must be initialized. 408 */ 409 static int 410 fss_softc_alloc(struct fss_softc *sc) 411 { 412 int i, error; 413 414 if ((sc->sc_flags & FSS_PERSISTENT) == 0) { 415 sc->sc_copied = 416 kmem_zalloc(howmany(sc->sc_clcount, NBBY), KM_SLEEP); 417 if (sc->sc_copied == NULL) 418 return(ENOMEM); 419 420 sc->sc_cache = kmem_alloc(sc->sc_cache_size * 421 sizeof(struct fss_cache), KM_SLEEP); 422 if (sc->sc_cache == NULL) 423 return(ENOMEM); 424 425 for (i = 0; i < sc->sc_cache_size; i++) { 426 sc->sc_cache[i].fc_type = FSS_CACHE_FREE; 427 sc->sc_cache[i].fc_data = 428 kmem_alloc(FSS_CLSIZE(sc), KM_SLEEP); 429 if (sc->sc_cache[i].fc_data == NULL) 430 return(ENOMEM); 431 cv_init(&sc->sc_cache[i].fc_state_cv, "cowwait1"); 432 } 433 434 sc->sc_indir_valid = 435 kmem_zalloc(howmany(sc->sc_indir_size, NBBY), KM_SLEEP); 436 if (sc->sc_indir_valid == NULL) 437 return(ENOMEM); 438 439 sc->sc_indir_data = kmem_zalloc(FSS_CLSIZE(sc), KM_SLEEP); 440 if (sc->sc_indir_data == NULL) 441 return(ENOMEM); 442 } else { 443 sc->sc_copied = NULL; 444 sc->sc_cache = NULL; 445 sc->sc_indir_valid = NULL; 446 sc->sc_indir_data = NULL; 447 } 448 449 sc->sc_flags |= FSS_BS_THREAD; 450 if ((error = kthread_create(PRI_BIO, 0, NULL, fss_bs_thread, sc, 451 &sc->sc_bs_lwp, device_xname(sc->sc_dev))) != 0) { 452 sc->sc_flags &= ~FSS_BS_THREAD; 453 return error; 454 } 455 456 disk_attach(sc->sc_dkdev); 457 458 return 0; 459 } 460 461 /* 462 * Free the variable sized parts of the softc. 463 */ 464 static void 465 fss_softc_free(struct fss_softc *sc) 466 { 467 int i; 468 469 if ((sc->sc_flags & FSS_BS_THREAD) != 0) { 470 mutex_enter(&sc->sc_slock); 471 sc->sc_flags &= ~FSS_BS_THREAD; 472 cv_signal(&sc->sc_work_cv); 473 while (sc->sc_bs_lwp != NULL) 474 kpause("fssdetach", false, 1, &sc->sc_slock); 475 mutex_exit(&sc->sc_slock); 476 } 477 478 disk_detach(sc->sc_dkdev); 479 480 if (sc->sc_copied != NULL) 481 kmem_free(sc->sc_copied, howmany(sc->sc_clcount, NBBY)); 482 sc->sc_copied = NULL; 483 484 if (sc->sc_cache != NULL) { 485 for (i = 0; i < sc->sc_cache_size; i++) 486 if (sc->sc_cache[i].fc_data != NULL) { 487 cv_destroy(&sc->sc_cache[i].fc_state_cv); 488 kmem_free(sc->sc_cache[i].fc_data, 489 FSS_CLSIZE(sc)); 490 } 491 kmem_free(sc->sc_cache, 492 sc->sc_cache_size*sizeof(struct fss_cache)); 493 } 494 sc->sc_cache = NULL; 495 496 if (sc->sc_indir_valid != NULL) 497 kmem_free(sc->sc_indir_valid, howmany(sc->sc_indir_size, NBBY)); 498 sc->sc_indir_valid = NULL; 499 500 if (sc->sc_indir_data != NULL) 501 kmem_free(sc->sc_indir_data, FSS_CLSIZE(sc)); 502 sc->sc_indir_data = NULL; 503 } 504 505 /* 506 * Set all active snapshots on this file system into ERROR state. 507 */ 508 static void 509 fss_unmount_hook(struct mount *mp) 510 { 511 int i; 512 struct fss_softc *sc; 513 514 mutex_enter(&fss_device_lock); 515 for (i = 0; i < fss_cd.cd_ndevs; i++) { 516 if ((sc = device_lookup_private(&fss_cd, i)) == NULL) 517 continue; 518 mutex_enter(&sc->sc_slock); 519 if ((sc->sc_flags & FSS_ACTIVE) != 0 && 520 sc->sc_mount == mp) 521 fss_error(sc, "forced unmount"); 522 mutex_exit(&sc->sc_slock); 523 } 524 mutex_exit(&fss_device_lock); 525 } 526 527 /* 528 * A buffer is written to the snapshotted block device. Copy to 529 * backing store if needed. 530 */ 531 static int 532 fss_copy_on_write(void *v, struct buf *bp, bool data_valid) 533 { 534 int error; 535 u_int32_t cl, ch, c; 536 struct fss_softc *sc = v; 537 538 mutex_enter(&sc->sc_slock); 539 if (!FSS_ISVALID(sc)) { 540 mutex_exit(&sc->sc_slock); 541 return 0; 542 } 543 544 cl = FSS_BTOCL(sc, dbtob(bp->b_blkno)); 545 ch = FSS_BTOCL(sc, dbtob(bp->b_blkno)+bp->b_bcount-1); 546 error = 0; 547 if (curlwp == uvm.pagedaemon_lwp) { 548 for (c = cl; c <= ch; c++) 549 if (isclr(sc->sc_copied, c)) { 550 error = ENOMEM; 551 break; 552 } 553 } 554 mutex_exit(&sc->sc_slock); 555 556 if (error == 0) 557 for (c = cl; c <= ch; c++) { 558 error = fss_read_cluster(sc, c); 559 if (error) 560 break; 561 } 562 563 return error; 564 } 565 566 /* 567 * Lookup and open needed files. 568 * 569 * For file system internal snapshot initializes sc_mntname, sc_mount, 570 * sc_bs_vp and sc_time. 571 * 572 * Otherwise returns dev and size of the underlying block device. 573 * Initializes sc_mntname, sc_mount, sc_bdev, sc_bs_vp and sc_mount 574 */ 575 static int 576 fss_create_files(struct fss_softc *sc, struct fss_set *fss, 577 off_t *bsize, struct lwp *l) 578 { 579 int error, bits, fsbsize; 580 struct timespec ts; 581 struct partinfo dpart; 582 struct vattr va; 583 struct nameidata nd; 584 585 /* 586 * Get the mounted file system. 587 */ 588 589 NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, fss->fss_mount); 590 if ((error = namei(&nd)) != 0) 591 return error; 592 593 if ((nd.ni_vp->v_vflag & VV_ROOT) != VV_ROOT) { 594 vrele(nd.ni_vp); 595 return EINVAL; 596 } 597 598 sc->sc_mount = nd.ni_vp->v_mount; 599 memcpy(sc->sc_mntname, sc->sc_mount->mnt_stat.f_mntonname, MNAMELEN); 600 601 vrele(nd.ni_vp); 602 603 /* 604 * Check for file system internal snapshot. 605 */ 606 607 NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_USERSPACE, fss->fss_bstore); 608 if ((error = namei(&nd)) != 0) 609 return error; 610 611 if (nd.ni_vp->v_type == VREG && nd.ni_vp->v_mount == sc->sc_mount) { 612 sc->sc_flags |= FSS_PERSISTENT; 613 sc->sc_bs_vp = nd.ni_vp; 614 615 fsbsize = sc->sc_bs_vp->v_mount->mnt_stat.f_iosize; 616 bits = sizeof(sc->sc_bs_bshift)*NBBY; 617 for (sc->sc_bs_bshift = 1; sc->sc_bs_bshift < bits; 618 sc->sc_bs_bshift++) 619 if (FSS_FSBSIZE(sc) == fsbsize) 620 break; 621 if (sc->sc_bs_bshift >= bits) { 622 VOP_UNLOCK(sc->sc_bs_vp, 0); 623 return EINVAL; 624 } 625 626 sc->sc_bs_bmask = FSS_FSBSIZE(sc)-1; 627 sc->sc_clshift = 0; 628 629 error = VFS_SNAPSHOT(sc->sc_mount, sc->sc_bs_vp, &ts); 630 TIMESPEC_TO_TIMEVAL(&sc->sc_time, &ts); 631 632 VOP_UNLOCK(sc->sc_bs_vp, 0); 633 634 return error; 635 } 636 vput(nd.ni_vp); 637 638 /* 639 * Get the block device it is mounted on. 640 */ 641 642 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, 643 sc->sc_mount->mnt_stat.f_mntfromname); 644 if ((error = namei(&nd)) != 0) 645 return error; 646 647 if (nd.ni_vp->v_type != VBLK) { 648 vrele(nd.ni_vp); 649 return EINVAL; 650 } 651 652 sc->sc_bdev = nd.ni_vp->v_rdev; 653 vrele(nd.ni_vp); 654 655 /* 656 * Get the block device size. 657 */ 658 659 error = bdev_ioctl(sc->sc_bdev, DIOCGPART, &dpart, FREAD, l); 660 if (error) 661 return error; 662 663 *bsize = (off_t)dpart.disklab->d_secsize*dpart.part->p_size; 664 665 /* 666 * Get the backing store 667 */ 668 669 NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, fss->fss_bstore); 670 if ((error = vn_open(&nd, FREAD|FWRITE, 0)) != 0) 671 return error; 672 VOP_UNLOCK(nd.ni_vp, 0); 673 674 sc->sc_bs_vp = nd.ni_vp; 675 676 if (nd.ni_vp->v_type != VREG && nd.ni_vp->v_type != VCHR) 677 return EINVAL; 678 679 if (sc->sc_bs_vp->v_type == VREG) { 680 error = VOP_GETATTR(sc->sc_bs_vp, &va, l->l_cred); 681 if (error != 0) 682 return error; 683 sc->sc_bs_size = va.va_size; 684 fsbsize = sc->sc_bs_vp->v_mount->mnt_stat.f_iosize; 685 if (fsbsize & (fsbsize-1)) /* No power of two */ 686 return EINVAL; 687 for (sc->sc_bs_bshift = 1; sc->sc_bs_bshift < 32; 688 sc->sc_bs_bshift++) 689 if (FSS_FSBSIZE(sc) == fsbsize) 690 break; 691 if (sc->sc_bs_bshift >= 32) 692 return EINVAL; 693 sc->sc_bs_bmask = FSS_FSBSIZE(sc)-1; 694 } else { 695 sc->sc_bs_bshift = DEV_BSHIFT; 696 sc->sc_bs_bmask = FSS_FSBSIZE(sc)-1; 697 } 698 699 return 0; 700 } 701 702 /* 703 * Create a snapshot. 704 */ 705 static int 706 fss_create_snapshot(struct fss_softc *sc, struct fss_set *fss, struct lwp *l) 707 { 708 int len, error; 709 u_int32_t csize; 710 off_t bsize; 711 712 bsize = 0; /* XXX gcc */ 713 714 /* 715 * Open needed files. 716 */ 717 if ((error = fss_create_files(sc, fss, &bsize, l)) != 0) 718 goto bad; 719 720 if (sc->sc_flags & FSS_PERSISTENT) { 721 fss_softc_alloc(sc); 722 sc->sc_flags |= FSS_ACTIVE; 723 return 0; 724 } 725 726 /* 727 * Set cluster size. Must be a power of two and 728 * a multiple of backing store block size. 729 */ 730 if (fss->fss_csize <= 0) 731 csize = MAXPHYS; 732 else 733 csize = fss->fss_csize; 734 if (bsize/csize > FSS_CLUSTER_MAX) 735 csize = bsize/FSS_CLUSTER_MAX+1; 736 737 for (sc->sc_clshift = sc->sc_bs_bshift; sc->sc_clshift < 32; 738 sc->sc_clshift++) 739 if (FSS_CLSIZE(sc) >= csize) 740 break; 741 if (sc->sc_clshift >= 32) { 742 error = EINVAL; 743 goto bad; 744 } 745 sc->sc_clmask = FSS_CLSIZE(sc)-1; 746 747 /* 748 * Set number of cache slots. 749 */ 750 if (FSS_CLSIZE(sc) <= 8192) 751 sc->sc_cache_size = 32; 752 else if (FSS_CLSIZE(sc) <= 65536) 753 sc->sc_cache_size = 8; 754 else 755 sc->sc_cache_size = 4; 756 757 /* 758 * Set number of clusters and size of last cluster. 759 */ 760 sc->sc_clcount = FSS_BTOCL(sc, bsize-1)+1; 761 sc->sc_clresid = FSS_CLOFF(sc, bsize-1)+1; 762 763 /* 764 * Set size of indirect table. 765 */ 766 len = sc->sc_clcount*sizeof(u_int32_t); 767 sc->sc_indir_size = FSS_BTOCL(sc, len)+1; 768 sc->sc_clnext = sc->sc_indir_size; 769 sc->sc_indir_cur = 0; 770 771 if ((error = fss_softc_alloc(sc)) != 0) 772 goto bad; 773 774 /* 775 * Activate the snapshot. 776 */ 777 778 if ((error = vfs_suspend(sc->sc_mount, 0)) != 0) 779 goto bad; 780 781 microtime(&sc->sc_time); 782 783 if (error == 0) 784 error = fscow_establish(sc->sc_mount, 785 fss_copy_on_write, sc); 786 if (error == 0) 787 sc->sc_flags |= FSS_ACTIVE; 788 789 vfs_resume(sc->sc_mount); 790 791 if (error != 0) 792 goto bad; 793 794 aprint_debug_dev(sc->sc_dev, "%s snapshot active\n", sc->sc_mntname); 795 aprint_debug_dev(sc->sc_dev, 796 "%u clusters of %u, %u cache slots, %u indir clusters\n", 797 sc->sc_clcount, FSS_CLSIZE(sc), 798 sc->sc_cache_size, sc->sc_indir_size); 799 800 return 0; 801 802 bad: 803 fss_softc_free(sc); 804 if (sc->sc_bs_vp != NULL) { 805 if (sc->sc_flags & FSS_PERSISTENT) 806 vn_close(sc->sc_bs_vp, FREAD, l->l_cred); 807 else 808 vn_close(sc->sc_bs_vp, FREAD|FWRITE, l->l_cred); 809 } 810 sc->sc_bs_vp = NULL; 811 812 return error; 813 } 814 815 /* 816 * Delete a snapshot. 817 */ 818 static int 819 fss_delete_snapshot(struct fss_softc *sc, struct lwp *l) 820 { 821 822 if ((sc->sc_flags & FSS_PERSISTENT) == 0) 823 fscow_disestablish(sc->sc_mount, fss_copy_on_write, sc); 824 825 mutex_enter(&sc->sc_slock); 826 sc->sc_flags &= ~(FSS_ACTIVE|FSS_ERROR); 827 sc->sc_mount = NULL; 828 sc->sc_bdev = NODEV; 829 mutex_exit(&sc->sc_slock); 830 831 fss_softc_free(sc); 832 if (sc->sc_flags & FSS_PERSISTENT) 833 vn_close(sc->sc_bs_vp, FREAD, l->l_cred); 834 else 835 vn_close(sc->sc_bs_vp, FREAD|FWRITE, l->l_cred); 836 sc->sc_bs_vp = NULL; 837 sc->sc_flags &= ~FSS_PERSISTENT; 838 839 return 0; 840 } 841 842 /* 843 * Read a cluster from the snapshotted block device to the cache. 844 */ 845 static int 846 fss_read_cluster(struct fss_softc *sc, u_int32_t cl) 847 { 848 int error, todo, offset, len; 849 daddr_t dblk; 850 struct buf *bp, *mbp; 851 struct fss_cache *scp, *scl; 852 853 /* 854 * Get a free cache slot. 855 */ 856 scl = sc->sc_cache+sc->sc_cache_size; 857 858 mutex_enter(&sc->sc_slock); 859 860 restart: 861 if (isset(sc->sc_copied, cl) || !FSS_ISVALID(sc)) { 862 mutex_exit(&sc->sc_slock); 863 return 0; 864 } 865 866 for (scp = sc->sc_cache; scp < scl; scp++) 867 if (scp->fc_cluster == cl) { 868 if (scp->fc_type == FSS_CACHE_VALID) { 869 mutex_exit(&sc->sc_slock); 870 return 0; 871 } else if (scp->fc_type == FSS_CACHE_BUSY) { 872 cv_wait(&scp->fc_state_cv, &sc->sc_slock); 873 goto restart; 874 } 875 } 876 877 for (scp = sc->sc_cache; scp < scl; scp++) 878 if (scp->fc_type == FSS_CACHE_FREE) { 879 scp->fc_type = FSS_CACHE_BUSY; 880 scp->fc_cluster = cl; 881 break; 882 } 883 if (scp >= scl) { 884 cv_wait(&sc->sc_cache_cv, &sc->sc_slock); 885 goto restart; 886 } 887 888 mutex_exit(&sc->sc_slock); 889 890 /* 891 * Start the read. 892 */ 893 dblk = btodb(FSS_CLTOB(sc, cl)); 894 if (cl == sc->sc_clcount-1) { 895 todo = sc->sc_clresid; 896 memset((char *)scp->fc_data + todo, 0, FSS_CLSIZE(sc) - todo); 897 } else 898 todo = FSS_CLSIZE(sc); 899 offset = 0; 900 mbp = getiobuf(NULL, true); 901 mbp->b_bufsize = todo; 902 mbp->b_data = scp->fc_data; 903 mbp->b_resid = mbp->b_bcount = todo; 904 mbp->b_flags = B_READ; 905 mbp->b_cflags = BC_BUSY; 906 mbp->b_dev = sc->sc_bdev; 907 while (todo > 0) { 908 len = todo; 909 if (len > MAXPHYS) 910 len = MAXPHYS; 911 if (btodb(FSS_CLTOB(sc, cl)) == dblk && len == todo) 912 bp = mbp; 913 else { 914 bp = getiobuf(NULL, true); 915 nestiobuf_setup(mbp, bp, offset, len); 916 } 917 bp->b_lblkno = 0; 918 bp->b_blkno = dblk; 919 bdev_strategy(bp); 920 dblk += btodb(len); 921 offset += len; 922 todo -= len; 923 } 924 error = biowait(mbp); 925 putiobuf(mbp); 926 927 mutex_enter(&sc->sc_slock); 928 scp->fc_type = (error ? FSS_CACHE_FREE : FSS_CACHE_VALID); 929 cv_broadcast(&scp->fc_state_cv); 930 if (error == 0) { 931 setbit(sc->sc_copied, scp->fc_cluster); 932 cv_signal(&sc->sc_work_cv); 933 } 934 mutex_exit(&sc->sc_slock); 935 936 return error; 937 } 938 939 /* 940 * Read/write clusters from/to backing store. 941 * For persistent snapshots must be called with cl == 0. off is the 942 * offset into the snapshot. 943 */ 944 static int 945 fss_bs_io(struct fss_softc *sc, fss_io_type rw, 946 u_int32_t cl, off_t off, int len, void *data) 947 { 948 int error; 949 950 off += FSS_CLTOB(sc, cl); 951 952 vn_lock(sc->sc_bs_vp, LK_EXCLUSIVE|LK_RETRY); 953 954 error = vn_rdwr((rw == FSS_READ ? UIO_READ : UIO_WRITE), sc->sc_bs_vp, 955 data, len, off, UIO_SYSSPACE, IO_UNIT|IO_NODELOCKED, 956 sc->sc_bs_lwp->l_cred, NULL, NULL); 957 if (error == 0) { 958 mutex_enter(&sc->sc_bs_vp->v_interlock); 959 error = VOP_PUTPAGES(sc->sc_bs_vp, trunc_page(off), 960 round_page(off+len), PGO_CLEANIT|PGO_SYNCIO|PGO_FREE); 961 } 962 963 VOP_UNLOCK(sc->sc_bs_vp, 0); 964 965 return error; 966 } 967 968 /* 969 * Get a pointer to the indirect slot for this cluster. 970 */ 971 static u_int32_t * 972 fss_bs_indir(struct fss_softc *sc, u_int32_t cl) 973 { 974 u_int32_t icl; 975 int ioff; 976 977 icl = cl/(FSS_CLSIZE(sc)/sizeof(u_int32_t)); 978 ioff = cl%(FSS_CLSIZE(sc)/sizeof(u_int32_t)); 979 980 if (sc->sc_indir_cur == icl) 981 return &sc->sc_indir_data[ioff]; 982 983 if (sc->sc_indir_dirty) { 984 if (fss_bs_io(sc, FSS_WRITE, sc->sc_indir_cur, 0, 985 FSS_CLSIZE(sc), (void *)sc->sc_indir_data) != 0) 986 return NULL; 987 setbit(sc->sc_indir_valid, sc->sc_indir_cur); 988 } 989 990 sc->sc_indir_dirty = 0; 991 sc->sc_indir_cur = icl; 992 993 if (isset(sc->sc_indir_valid, sc->sc_indir_cur)) { 994 if (fss_bs_io(sc, FSS_READ, sc->sc_indir_cur, 0, 995 FSS_CLSIZE(sc), (void *)sc->sc_indir_data) != 0) 996 return NULL; 997 } else 998 memset(sc->sc_indir_data, 0, FSS_CLSIZE(sc)); 999 1000 return &sc->sc_indir_data[ioff]; 1001 } 1002 1003 /* 1004 * The kernel thread (one for every active snapshot). 1005 * 1006 * After wakeup it cleans the cache and runs the I/O requests. 1007 */ 1008 static void 1009 fss_bs_thread(void *arg) 1010 { 1011 bool thread_idle, is_valid; 1012 int error, i, todo, len, crotor, is_read; 1013 long off; 1014 char *addr; 1015 u_int32_t c, cl, ch, *indirp; 1016 struct buf *bp, *nbp; 1017 struct fss_softc *sc; 1018 struct fss_cache *scp, *scl; 1019 1020 sc = arg; 1021 scl = sc->sc_cache+sc->sc_cache_size; 1022 crotor = 0; 1023 thread_idle = false; 1024 1025 mutex_enter(&sc->sc_slock); 1026 1027 for (;;) { 1028 if (thread_idle) 1029 cv_wait(&sc->sc_work_cv, &sc->sc_slock); 1030 thread_idle = true; 1031 if ((sc->sc_flags & FSS_BS_THREAD) == 0) { 1032 sc->sc_bs_lwp = NULL; 1033 mutex_exit(&sc->sc_slock); 1034 kthread_exit(0); 1035 } 1036 1037 /* 1038 * Process I/O requests (persistent) 1039 */ 1040 1041 if (sc->sc_flags & FSS_PERSISTENT) { 1042 if ((bp = BUFQ_GET(sc->sc_bufq)) == NULL) 1043 continue; 1044 is_valid = FSS_ISVALID(sc); 1045 is_read = (bp->b_flags & B_READ); 1046 thread_idle = false; 1047 mutex_exit(&sc->sc_slock); 1048 1049 if (is_valid) { 1050 disk_busy(sc->sc_dkdev); 1051 error = fss_bs_io(sc, FSS_READ, 0, 1052 dbtob(bp->b_blkno), bp->b_bcount, 1053 bp->b_data); 1054 disk_unbusy(sc->sc_dkdev, 1055 (error ? 0 : bp->b_bcount), is_read); 1056 } else 1057 error = ENXIO; 1058 1059 bp->b_error = error; 1060 bp->b_resid = (error ? bp->b_bcount : 0); 1061 biodone(bp); 1062 1063 mutex_enter(&sc->sc_slock); 1064 continue; 1065 } 1066 1067 /* 1068 * Clean the cache 1069 */ 1070 for (i = 0; i < sc->sc_cache_size; i++) { 1071 crotor = (crotor + 1) % sc->sc_cache_size; 1072 scp = sc->sc_cache + crotor; 1073 if (scp->fc_type != FSS_CACHE_VALID) 1074 continue; 1075 mutex_exit(&sc->sc_slock); 1076 1077 thread_idle = false; 1078 indirp = fss_bs_indir(sc, scp->fc_cluster); 1079 if (indirp != NULL) { 1080 error = fss_bs_io(sc, FSS_WRITE, sc->sc_clnext, 1081 0, FSS_CLSIZE(sc), scp->fc_data); 1082 } else 1083 error = EIO; 1084 1085 mutex_enter(&sc->sc_slock); 1086 if (error == 0) { 1087 *indirp = sc->sc_clnext++; 1088 sc->sc_indir_dirty = 1; 1089 } else 1090 fss_error(sc, "write error on backing store"); 1091 1092 scp->fc_type = FSS_CACHE_FREE; 1093 cv_signal(&sc->sc_cache_cv); 1094 break; 1095 } 1096 1097 /* 1098 * Process I/O requests 1099 */ 1100 if ((bp = BUFQ_GET(sc->sc_bufq)) == NULL) 1101 continue; 1102 is_valid = FSS_ISVALID(sc); 1103 is_read = (bp->b_flags & B_READ); 1104 thread_idle = false; 1105 1106 if (!is_valid) { 1107 mutex_exit(&sc->sc_slock); 1108 1109 bp->b_error = ENXIO; 1110 bp->b_resid = bp->b_bcount; 1111 biodone(bp); 1112 1113 mutex_enter(&sc->sc_slock); 1114 continue; 1115 } 1116 1117 disk_busy(sc->sc_dkdev); 1118 1119 /* 1120 * First read from the snapshotted block device unless 1121 * this request is completely covered by backing store. 1122 */ 1123 1124 cl = FSS_BTOCL(sc, dbtob(bp->b_blkno)); 1125 off = FSS_CLOFF(sc, dbtob(bp->b_blkno)); 1126 ch = FSS_BTOCL(sc, dbtob(bp->b_blkno)+bp->b_bcount-1); 1127 error = 0; 1128 bp->b_resid = 0; 1129 bp->b_error = 0; 1130 for (c = cl; c <= ch; c++) { 1131 if (isset(sc->sc_copied, c)) 1132 continue; 1133 mutex_exit(&sc->sc_slock); 1134 1135 /* Not on backing store, read from device. */ 1136 nbp = getiobuf(NULL, true); 1137 nbp->b_flags = B_READ; 1138 nbp->b_resid = nbp->b_bcount = bp->b_bcount; 1139 nbp->b_bufsize = bp->b_bcount; 1140 nbp->b_data = bp->b_data; 1141 nbp->b_blkno = bp->b_blkno; 1142 nbp->b_lblkno = 0; 1143 nbp->b_dev = sc->sc_bdev; 1144 SET(nbp->b_cflags, BC_BUSY); /* mark buffer busy */ 1145 1146 bdev_strategy(nbp); 1147 1148 error = biowait(nbp); 1149 if (error != 0) { 1150 bp->b_resid = bp->b_bcount; 1151 bp->b_error = nbp->b_error; 1152 disk_unbusy(sc->sc_dkdev, 0, is_read); 1153 biodone(bp); 1154 } 1155 putiobuf(nbp); 1156 1157 mutex_enter(&sc->sc_slock); 1158 break; 1159 } 1160 if (error) 1161 continue; 1162 1163 /* 1164 * Replace those parts that have been saved to backing store. 1165 */ 1166 1167 addr = bp->b_data; 1168 todo = bp->b_bcount; 1169 for (c = cl; c <= ch; c++, off = 0, todo -= len, addr += len) { 1170 len = FSS_CLSIZE(sc)-off; 1171 if (len > todo) 1172 len = todo; 1173 if (isclr(sc->sc_copied, c)) 1174 continue; 1175 mutex_exit(&sc->sc_slock); 1176 1177 indirp = fss_bs_indir(sc, c); 1178 if (indirp == NULL || *indirp == 0) { 1179 /* 1180 * Not on backing store. Either in cache 1181 * or hole in the snapshotted block device. 1182 */ 1183 1184 mutex_enter(&sc->sc_slock); 1185 for (scp = sc->sc_cache; scp < scl; scp++) 1186 if (scp->fc_type == FSS_CACHE_VALID && 1187 scp->fc_cluster == c) 1188 break; 1189 if (scp < scl) 1190 memcpy(addr, (char *)scp->fc_data+off, 1191 len); 1192 else 1193 memset(addr, 0, len); 1194 continue; 1195 } 1196 1197 /* 1198 * Read from backing store. 1199 */ 1200 error = 1201 fss_bs_io(sc, FSS_READ, *indirp, off, len, addr); 1202 1203 mutex_enter(&sc->sc_slock); 1204 if (error) { 1205 bp->b_resid = bp->b_bcount; 1206 bp->b_error = error; 1207 break; 1208 } 1209 } 1210 mutex_exit(&sc->sc_slock); 1211 1212 disk_unbusy(sc->sc_dkdev, (error ? 0 : bp->b_bcount), is_read); 1213 biodone(bp); 1214 1215 mutex_enter(&sc->sc_slock); 1216 } 1217 } 1218 1219 #ifdef _MODULE 1220 1221 #include <sys/module.h> 1222 1223 MODULE(MODULE_CLASS_DRIVER, fss, NULL); 1224 CFDRIVER_DECL(fss, DV_DISK, NULL); 1225 1226 static int 1227 fss_modcmd(modcmd_t cmd, void *arg) 1228 { 1229 int bmajor = -1, cmajor = -1, error = 0; 1230 1231 switch (cmd) { 1232 case MODULE_CMD_INIT: 1233 mutex_init(&fss_device_lock, MUTEX_DEFAULT, IPL_NONE); 1234 error = config_cfdriver_attach(&fss_cd); 1235 if (error) { 1236 mutex_destroy(&fss_device_lock); 1237 break; 1238 } 1239 error = config_cfattach_attach(fss_cd.cd_name, &fss_ca); 1240 if (error) { 1241 config_cfdriver_detach(&fss_cd); 1242 mutex_destroy(&fss_device_lock); 1243 break; 1244 } 1245 error = devsw_attach(fss_cd.cd_name, 1246 &fss_bdevsw, &bmajor, &fss_cdevsw, &cmajor); 1247 if (error) { 1248 config_cfattach_detach(fss_cd.cd_name, &fss_ca); 1249 config_cfdriver_detach(&fss_cd); 1250 mutex_destroy(&fss_device_lock); 1251 break; 1252 } 1253 break; 1254 1255 case MODULE_CMD_FINI: 1256 error = config_cfattach_detach(fss_cd.cd_name, &fss_ca); 1257 if (error) 1258 break; 1259 config_cfdriver_detach(&fss_cd); 1260 devsw_detach(&fss_bdevsw, &fss_cdevsw); 1261 mutex_destroy(&fss_device_lock); 1262 break; 1263 1264 default: 1265 error = ENOTTY; 1266 break; 1267 } 1268 1269 return error; 1270 } 1271 1272 #endif /* _MODULE */
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