fss.c revision 1.46
1 /* $NetBSD: fss.c,v 1.46 2008/06/17 14:53:10 reinoud 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 1.46 2008/06/17 14:53:10 reinoud Exp $"); 40 41 #include "fss.h" 42 43 #include <sys/param.h> 44 #include <sys/systm.h> 45 #include <sys/namei.h> 46 #include <sys/proc.h> 47 #include <sys/errno.h> 48 #include <sys/buf.h> 49 #include <sys/malloc.h> 50 #include <sys/ioctl.h> 51 #include <sys/disklabel.h> 52 #include <sys/device.h> 53 #include <sys/disk.h> 54 #include <sys/stat.h> 55 #include <sys/mount.h> 56 #include <sys/vnode.h> 57 #include <sys/file.h> 58 #include <sys/uio.h> 59 #include <sys/conf.h> 60 #include <sys/kthread.h> 61 #include <sys/fstrans.h> 62 #include <sys/simplelock.h> 63 64 #include <miscfs/specfs/specdev.h> 65 66 #include <dev/fssvar.h> 67 68 #include <machine/stdarg.h> 69 70 #ifdef DEBUG 71 #define FSS_STATISTICS 72 #endif 73 74 #ifdef FSS_STATISTICS 75 struct fss_stat { 76 u_int64_t cow_calls; 77 u_int64_t cow_copied; 78 u_int64_t cow_cache_full; 79 u_int64_t indir_read; 80 u_int64_t indir_write; 81 }; 82 83 static struct fss_stat fss_stat[NFSS]; 84 85 #define FSS_STAT_INC(sc, field) \ 86 do { \ 87 fss_stat[sc->sc_unit].field++; \ 88 } while (0) 89 #define FSS_STAT_SET(sc, field, value) \ 90 do { \ 91 fss_stat[sc->sc_unit].field = value; \ 92 } while (0) 93 #define FSS_STAT_ADD(sc, field, value) \ 94 do { \ 95 fss_stat[sc->sc_unit].field += value; \ 96 } while (0) 97 #define FSS_STAT_VAL(sc, field) fss_stat[sc->sc_unit].field 98 #define FSS_STAT_CLEAR(sc) \ 99 do { \ 100 memset(&fss_stat[sc->sc_unit], 0, \ 101 sizeof(struct fss_stat)); \ 102 } while (0) 103 #else /* FSS_STATISTICS */ 104 #define FSS_STAT_INC(sc, field) 105 #define FSS_STAT_SET(sc, field, value) 106 #define FSS_STAT_ADD(sc, field, value) 107 #define FSS_STAT_CLEAR(sc) 108 #endif /* FSS_STATISTICS */ 109 110 static struct fss_softc fss_softc[NFSS]; 111 112 void fssattach(int); 113 114 dev_type_open(fss_open); 115 dev_type_close(fss_close); 116 dev_type_read(fss_read); 117 dev_type_write(fss_write); 118 dev_type_ioctl(fss_ioctl); 119 dev_type_strategy(fss_strategy); 120 dev_type_dump(fss_dump); 121 dev_type_size(fss_size); 122 123 static int fss_copy_on_write(void *, struct buf *, bool); 124 static inline void fss_error(struct fss_softc *, const char *, ...); 125 static int fss_create_files(struct fss_softc *, struct fss_set *, 126 off_t *, struct lwp *); 127 static int fss_create_snapshot(struct fss_softc *, struct fss_set *, 128 struct lwp *); 129 static int fss_delete_snapshot(struct fss_softc *, struct lwp *); 130 static int fss_softc_alloc(struct fss_softc *); 131 static void fss_softc_free(struct fss_softc *); 132 static void fss_cluster_iodone(struct buf *); 133 static void fss_read_cluster(struct fss_softc *, u_int32_t); 134 static void fss_bs_thread(void *); 135 static int fss_bs_io(struct fss_softc *, fss_io_type, 136 u_int32_t, off_t, int, void *); 137 static u_int32_t *fss_bs_indir(struct fss_softc *, u_int32_t); 138 139 const struct bdevsw fss_bdevsw = { 140 fss_open, fss_close, fss_strategy, fss_ioctl, 141 fss_dump, fss_size, D_DISK 142 }; 143 144 const struct cdevsw fss_cdevsw = { 145 fss_open, fss_close, fss_read, fss_write, fss_ioctl, 146 nostop, notty, nopoll, nommap, nokqfilter, D_DISK 147 }; 148 149 void 150 fssattach(int num) 151 { 152 int i; 153 struct fss_softc *sc; 154 155 for (i = 0; i < NFSS; i++) { 156 sc = &fss_softc[i]; 157 sc->sc_unit = i; 158 sc->sc_bdev = NODEV; 159 simple_lock_init(&sc->sc_slock); 160 mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_NONE); 161 bufq_alloc(&sc->sc_bufq, "fcfs", 0); 162 } 163 } 164 165 int 166 fss_open(dev_t dev, int flags, int mode, struct lwp *l) 167 { 168 int s, mflag; 169 struct fss_softc *sc; 170 171 mflag = (mode == S_IFCHR ? FSS_CDEV_OPEN : FSS_BDEV_OPEN); 172 173 if ((sc = FSS_DEV_TO_SOFTC(dev)) == NULL) 174 return ENODEV; 175 176 FSS_LOCK(sc, s); 177 178 sc->sc_flags |= mflag; 179 180 FSS_UNLOCK(sc, s); 181 182 return 0; 183 } 184 185 int 186 fss_close(dev_t dev, int flags, int mode, struct lwp *l) 187 { 188 int s, mflag, error; 189 struct fss_softc *sc; 190 191 mflag = (mode == S_IFCHR ? FSS_CDEV_OPEN : FSS_BDEV_OPEN); 192 193 if ((sc = FSS_DEV_TO_SOFTC(dev)) == NULL) 194 return ENODEV; 195 196 FSS_LOCK(sc, s); 197 198 if ((sc->sc_flags & (FSS_CDEV_OPEN|FSS_BDEV_OPEN)) == mflag) { 199 if ((sc->sc_uflags & FSS_UNCONFIG_ON_CLOSE) != 0 && 200 (sc->sc_flags & FSS_ACTIVE) != 0) { 201 FSS_UNLOCK(sc, s); 202 error = fss_ioctl(dev, FSSIOCCLR, NULL, FWRITE, l); 203 if (error) 204 return error; 205 FSS_LOCK(sc, s); 206 } 207 sc->sc_uflags &= ~FSS_UNCONFIG_ON_CLOSE; 208 } 209 210 sc->sc_flags &= ~mflag; 211 212 FSS_UNLOCK(sc, s); 213 214 return 0; 215 } 216 217 void 218 fss_strategy(struct buf *bp) 219 { 220 int s; 221 struct fss_softc *sc; 222 223 sc = FSS_DEV_TO_SOFTC(bp->b_dev); 224 225 FSS_LOCK(sc, s); 226 227 if ((bp->b_flags & B_READ) != B_READ || 228 sc == NULL || !FSS_ISVALID(sc)) { 229 230 FSS_UNLOCK(sc, s); 231 232 bp->b_error = (sc == NULL ? ENODEV : EROFS); 233 bp->b_resid = bp->b_bcount; 234 biodone(bp); 235 return; 236 } 237 238 bp->b_rawblkno = bp->b_blkno; 239 BUFQ_PUT(sc->sc_bufq, bp); 240 wakeup(&sc->sc_bs_lwp); 241 242 FSS_UNLOCK(sc, s); 243 } 244 245 int 246 fss_read(dev_t dev, struct uio *uio, int flags) 247 { 248 return physio(fss_strategy, NULL, dev, B_READ, minphys, uio); 249 } 250 251 int 252 fss_write(dev_t dev, struct uio *uio, int flags) 253 { 254 return physio(fss_strategy, NULL, dev, B_WRITE, minphys, uio); 255 } 256 257 int 258 fss_ioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l) 259 { 260 int error; 261 struct fss_softc *sc; 262 struct fss_set *fss = (struct fss_set *)data; 263 struct fss_get *fsg = (struct fss_get *)data; 264 265 if ((sc = FSS_DEV_TO_SOFTC(dev)) == NULL) 266 return ENODEV; 267 268 switch (cmd) { 269 case FSSIOCSET: 270 mutex_enter(&sc->sc_lock); 271 if ((flag & FWRITE) == 0) 272 error = EPERM; 273 else if ((sc->sc_flags & FSS_ACTIVE) != 0) 274 error = EBUSY; 275 else 276 error = fss_create_snapshot(sc, fss, l); 277 mutex_exit(&sc->sc_lock); 278 break; 279 280 case FSSIOCCLR: 281 mutex_enter(&sc->sc_lock); 282 if ((flag & FWRITE) == 0) 283 error = EPERM; 284 else if ((sc->sc_flags & FSS_ACTIVE) == 0) 285 error = ENXIO; 286 else 287 error = fss_delete_snapshot(sc, l); 288 mutex_exit(&sc->sc_lock); 289 break; 290 291 case FSSIOCGET: 292 mutex_enter(&sc->sc_lock); 293 switch (sc->sc_flags & (FSS_PERSISTENT | FSS_ACTIVE)) { 294 case FSS_ACTIVE: 295 memcpy(fsg->fsg_mount, sc->sc_mntname, MNAMELEN); 296 fsg->fsg_csize = FSS_CLSIZE(sc); 297 fsg->fsg_time = sc->sc_time; 298 fsg->fsg_mount_size = sc->sc_clcount; 299 fsg->fsg_bs_size = sc->sc_clnext; 300 error = 0; 301 break; 302 case FSS_PERSISTENT | FSS_ACTIVE: 303 memcpy(fsg->fsg_mount, sc->sc_mntname, MNAMELEN); 304 fsg->fsg_csize = 0; 305 fsg->fsg_time = sc->sc_time; 306 fsg->fsg_mount_size = 0; 307 fsg->fsg_bs_size = 0; 308 error = 0; 309 break; 310 default: 311 error = ENXIO; 312 break; 313 } 314 mutex_exit(&sc->sc_lock); 315 break; 316 317 case FSSIOFSET: 318 sc->sc_uflags = *(int *)data; 319 error = 0; 320 break; 321 322 case FSSIOFGET: 323 *(int *)data = sc->sc_uflags; 324 error = 0; 325 break; 326 327 default: 328 error = EINVAL; 329 break; 330 } 331 332 return error; 333 } 334 335 int 336 fss_size(dev_t dev) 337 { 338 return -1; 339 } 340 341 int 342 fss_dump(dev_t dev, daddr_t blkno, void *va, 343 size_t size) 344 { 345 return EROFS; 346 } 347 348 /* 349 * An error occurred reading or writing the snapshot or backing store. 350 * If it is the first error log to console. 351 * The caller holds the simplelock. 352 */ 353 static inline void 354 fss_error(struct fss_softc *sc, const char *fmt, ...) 355 { 356 va_list ap; 357 358 if ((sc->sc_flags & (FSS_ACTIVE|FSS_ERROR)) == FSS_ACTIVE) { 359 va_start(ap, fmt); 360 printf("fss%d: snapshot invalid: ", sc->sc_unit); 361 vprintf(fmt, ap); 362 printf("\n"); 363 va_end(ap); 364 } 365 if ((sc->sc_flags & FSS_ACTIVE) == FSS_ACTIVE) 366 sc->sc_flags |= FSS_ERROR; 367 } 368 369 /* 370 * Allocate the variable sized parts of the softc and 371 * fork the kernel thread. 372 * 373 * The fields sc_clcount, sc_clshift, sc_cache_size and sc_indir_size 374 * must be initialized. 375 */ 376 static int 377 fss_softc_alloc(struct fss_softc *sc) 378 { 379 int i, len, error; 380 381 len = (sc->sc_clcount+NBBY-1)/NBBY; 382 sc->sc_copied = malloc(len, M_TEMP, M_ZERO|M_WAITOK|M_CANFAIL); 383 if (sc->sc_copied == NULL) 384 return(ENOMEM); 385 386 len = sc->sc_cache_size*sizeof(struct fss_cache); 387 sc->sc_cache = malloc(len, M_TEMP, M_ZERO|M_WAITOK|M_CANFAIL); 388 if (sc->sc_cache == NULL) 389 return(ENOMEM); 390 391 len = FSS_CLSIZE(sc); 392 for (i = 0; i < sc->sc_cache_size; i++) { 393 sc->sc_cache[i].fc_type = FSS_CACHE_FREE; 394 sc->sc_cache[i].fc_softc = sc; 395 sc->sc_cache[i].fc_xfercount = 0; 396 sc->sc_cache[i].fc_data = malloc(len, M_TEMP, 397 M_WAITOK|M_CANFAIL); 398 if (sc->sc_cache[i].fc_data == NULL) 399 return(ENOMEM); 400 } 401 402 len = (sc->sc_indir_size+NBBY-1)/NBBY; 403 sc->sc_indir_valid = malloc(len, M_TEMP, M_ZERO|M_WAITOK|M_CANFAIL); 404 if (sc->sc_indir_valid == NULL) 405 return(ENOMEM); 406 407 len = FSS_CLSIZE(sc); 408 sc->sc_indir_data = malloc(len, M_TEMP, M_ZERO|M_WAITOK|M_CANFAIL); 409 if (sc->sc_indir_data == NULL) 410 return(ENOMEM); 411 412 if ((error = kthread_create(PRI_BIO, 0, NULL, fss_bs_thread, sc, 413 &sc->sc_bs_lwp, "fssbs%d", sc->sc_unit)) != 0) 414 return error; 415 416 sc->sc_flags |= FSS_BS_THREAD; 417 return 0; 418 } 419 420 /* 421 * Free the variable sized parts of the softc. 422 */ 423 static void 424 fss_softc_free(struct fss_softc *sc) 425 { 426 int s, i; 427 428 if ((sc->sc_flags & FSS_BS_THREAD) != 0) { 429 FSS_LOCK(sc, s); 430 sc->sc_flags &= ~FSS_BS_THREAD; 431 wakeup(&sc->sc_bs_lwp); 432 while (sc->sc_bs_lwp != NULL) 433 ltsleep(&sc->sc_bs_lwp, PRIBIO, "fssthread", 0, 434 &sc->sc_slock); 435 FSS_UNLOCK(sc, s); 436 } 437 438 if (sc->sc_copied != NULL) 439 free(sc->sc_copied, M_TEMP); 440 sc->sc_copied = NULL; 441 442 if (sc->sc_cache != NULL) { 443 for (i = 0; i < sc->sc_cache_size; i++) 444 if (sc->sc_cache[i].fc_data != NULL) 445 free(sc->sc_cache[i].fc_data, M_TEMP); 446 free(sc->sc_cache, M_TEMP); 447 } 448 sc->sc_cache = NULL; 449 450 if (sc->sc_indir_valid != NULL) 451 free(sc->sc_indir_valid, M_TEMP); 452 sc->sc_indir_valid = NULL; 453 454 if (sc->sc_indir_data != NULL) 455 free(sc->sc_indir_data, M_TEMP); 456 sc->sc_indir_data = NULL; 457 } 458 459 /* 460 * Check if an unmount is ok. If forced, set this snapshot into ERROR state. 461 */ 462 int 463 fss_umount_hook(struct mount *mp, int forced) 464 { 465 int i, s; 466 467 for (i = 0; i < NFSS; i++) { 468 FSS_LOCK(&fss_softc[i], s); 469 if ((fss_softc[i].sc_flags & FSS_ACTIVE) != 0 && 470 fss_softc[i].sc_mount == mp) { 471 if (forced) 472 fss_error(&fss_softc[i], "forced unmount"); 473 else { 474 FSS_UNLOCK(&fss_softc[i], s); 475 return EBUSY; 476 } 477 } 478 FSS_UNLOCK(&fss_softc[i], s); 479 } 480 481 return 0; 482 } 483 484 /* 485 * A buffer is written to the snapshotted block device. Copy to 486 * backing store if needed. 487 */ 488 static int 489 fss_copy_on_write(void *v, struct buf *bp, bool data_valid) 490 { 491 int s; 492 u_int32_t cl, ch, c; 493 struct fss_softc *sc = v; 494 495 FSS_LOCK(sc, s); 496 if (!FSS_ISVALID(sc)) { 497 FSS_UNLOCK(sc, s); 498 return 0; 499 } 500 501 FSS_UNLOCK(sc, s); 502 503 FSS_STAT_INC(sc, cow_calls); 504 505 cl = FSS_BTOCL(sc, dbtob(bp->b_blkno)); 506 ch = FSS_BTOCL(sc, dbtob(bp->b_blkno)+bp->b_bcount-1); 507 508 for (c = cl; c <= ch; c++) 509 fss_read_cluster(sc, c); 510 511 return 0; 512 } 513 514 /* 515 * Lookup and open needed files. 516 * 517 * For file system internal snapshot initializes sc_mntname, sc_mount, 518 * sc_bs_vp and sc_time. 519 * 520 * Otherwise returns dev and size of the underlying block device. 521 * Initializes sc_mntname, sc_mount, sc_bdev, sc_bs_vp and sc_mount 522 */ 523 static int 524 fss_create_files(struct fss_softc *sc, struct fss_set *fss, 525 off_t *bsize, struct lwp *l) 526 { 527 int error, bits, fsbsize; 528 struct timespec ts; 529 struct partinfo dpart; 530 struct vattr va; 531 struct nameidata nd; 532 533 /* 534 * Get the mounted file system. 535 */ 536 537 NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, fss->fss_mount); 538 if ((error = namei(&nd)) != 0) 539 return error; 540 541 if ((nd.ni_vp->v_vflag & VV_ROOT) != VV_ROOT) { 542 vrele(nd.ni_vp); 543 return EINVAL; 544 } 545 546 sc->sc_mount = nd.ni_vp->v_mount; 547 memcpy(sc->sc_mntname, sc->sc_mount->mnt_stat.f_mntonname, MNAMELEN); 548 549 vrele(nd.ni_vp); 550 551 /* 552 * Check for file system internal snapshot. 553 */ 554 555 NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, fss->fss_bstore); 556 if ((error = namei(&nd)) != 0) 557 return error; 558 559 if (nd.ni_vp->v_type == VREG && nd.ni_vp->v_mount == sc->sc_mount) { 560 vrele(nd.ni_vp); 561 sc->sc_flags |= FSS_PERSISTENT; 562 563 NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, fss->fss_bstore); 564 if ((error = vn_open(&nd, FREAD, 0)) != 0) 565 return error; 566 sc->sc_bs_vp = nd.ni_vp; 567 568 fsbsize = sc->sc_bs_vp->v_mount->mnt_stat.f_iosize; 569 bits = sizeof(sc->sc_bs_bshift)*NBBY; 570 for (sc->sc_bs_bshift = 1; sc->sc_bs_bshift < bits; 571 sc->sc_bs_bshift++) 572 if (FSS_FSBSIZE(sc) == fsbsize) 573 break; 574 if (sc->sc_bs_bshift >= bits) { 575 VOP_UNLOCK(sc->sc_bs_vp, 0); 576 return EINVAL; 577 } 578 579 sc->sc_bs_bmask = FSS_FSBSIZE(sc)-1; 580 sc->sc_clshift = 0; 581 582 error = VFS_SNAPSHOT(sc->sc_mount, sc->sc_bs_vp, &ts); 583 TIMESPEC_TO_TIMEVAL(&sc->sc_time, &ts); 584 585 VOP_UNLOCK(sc->sc_bs_vp, 0); 586 587 return error; 588 } 589 vrele(nd.ni_vp); 590 591 /* 592 * Get the block device it is mounted on. 593 */ 594 595 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, 596 sc->sc_mount->mnt_stat.f_mntfromname); 597 if ((error = namei(&nd)) != 0) 598 return error; 599 600 if (nd.ni_vp->v_type != VBLK) { 601 vrele(nd.ni_vp); 602 return EINVAL; 603 } 604 605 error = VOP_IOCTL(nd.ni_vp, DIOCGPART, &dpart, FREAD, l->l_cred); 606 if (error) { 607 vrele(nd.ni_vp); 608 return error; 609 } 610 611 sc->sc_bdev = nd.ni_vp->v_rdev; 612 *bsize = (off_t)dpart.disklab->d_secsize*dpart.part->p_size; 613 vrele(nd.ni_vp); 614 615 /* 616 * Get the backing store 617 */ 618 619 NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, fss->fss_bstore); 620 if ((error = vn_open(&nd, FREAD|FWRITE, 0)) != 0) 621 return error; 622 VOP_UNLOCK(nd.ni_vp, 0); 623 624 sc->sc_bs_vp = nd.ni_vp; 625 626 if (nd.ni_vp->v_type != VREG && nd.ni_vp->v_type != VCHR) 627 return EINVAL; 628 629 if (sc->sc_bs_vp->v_type == VREG) { 630 error = VOP_GETATTR(sc->sc_bs_vp, &va, l->l_cred); 631 if (error != 0) 632 return error; 633 sc->sc_bs_size = va.va_size; 634 fsbsize = sc->sc_bs_vp->v_mount->mnt_stat.f_iosize; 635 if (fsbsize & (fsbsize-1)) /* No power of two */ 636 return EINVAL; 637 for (sc->sc_bs_bshift = 1; sc->sc_bs_bshift < 32; 638 sc->sc_bs_bshift++) 639 if (FSS_FSBSIZE(sc) == fsbsize) 640 break; 641 if (sc->sc_bs_bshift >= 32) 642 return EINVAL; 643 sc->sc_bs_bmask = FSS_FSBSIZE(sc)-1; 644 } else { 645 sc->sc_bs_bshift = DEV_BSHIFT; 646 sc->sc_bs_bmask = FSS_FSBSIZE(sc)-1; 647 } 648 649 /* 650 * As all IO to from/to the backing store goes through 651 * VOP_STRATEGY() clean the buffer cache to prevent 652 * cache incoherencies. 653 */ 654 if ((error = vinvalbuf(sc->sc_bs_vp, V_SAVE, l->l_cred, l, 0, 0)) != 0) 655 return error; 656 657 return 0; 658 } 659 660 /* 661 * Create a snapshot. 662 */ 663 static int 664 fss_create_snapshot(struct fss_softc *sc, struct fss_set *fss, struct lwp *l) 665 { 666 int len, error; 667 u_int32_t csize; 668 off_t bsize; 669 670 bsize = 0; /* XXX gcc */ 671 672 /* 673 * Open needed files. 674 */ 675 if ((error = fss_create_files(sc, fss, &bsize, l)) != 0) 676 goto bad; 677 678 if (sc->sc_flags & FSS_PERSISTENT) { 679 fss_softc_alloc(sc); 680 sc->sc_flags |= FSS_ACTIVE; 681 return 0; 682 } 683 684 /* 685 * Set cluster size. Must be a power of two and 686 * a multiple of backing store block size. 687 */ 688 if (fss->fss_csize <= 0) 689 csize = MAXPHYS; 690 else 691 csize = fss->fss_csize; 692 if (bsize/csize > FSS_CLUSTER_MAX) 693 csize = bsize/FSS_CLUSTER_MAX+1; 694 695 for (sc->sc_clshift = sc->sc_bs_bshift; sc->sc_clshift < 32; 696 sc->sc_clshift++) 697 if (FSS_CLSIZE(sc) >= csize) 698 break; 699 if (sc->sc_clshift >= 32) { 700 error = EINVAL; 701 goto bad; 702 } 703 sc->sc_clmask = FSS_CLSIZE(sc)-1; 704 705 /* 706 * Set number of cache slots. 707 */ 708 if (FSS_CLSIZE(sc) <= 8192) 709 sc->sc_cache_size = 32; 710 else if (FSS_CLSIZE(sc) <= 65536) 711 sc->sc_cache_size = 8; 712 else 713 sc->sc_cache_size = 4; 714 715 /* 716 * Set number of clusters and size of last cluster. 717 */ 718 sc->sc_clcount = FSS_BTOCL(sc, bsize-1)+1; 719 sc->sc_clresid = FSS_CLOFF(sc, bsize-1)+1; 720 721 /* 722 * Set size of indirect table. 723 */ 724 len = sc->sc_clcount*sizeof(u_int32_t); 725 sc->sc_indir_size = FSS_BTOCL(sc, len)+1; 726 sc->sc_clnext = sc->sc_indir_size; 727 sc->sc_indir_cur = 0; 728 729 if ((error = fss_softc_alloc(sc)) != 0) 730 goto bad; 731 732 /* 733 * Activate the snapshot. 734 */ 735 736 if ((error = vfs_suspend(sc->sc_mount, 0)) != 0) 737 goto bad; 738 739 microtime(&sc->sc_time); 740 741 if (error == 0) 742 error = fscow_establish(sc->sc_mount, 743 fss_copy_on_write, sc); 744 if (error == 0) 745 sc->sc_flags |= FSS_ACTIVE; 746 747 vfs_resume(sc->sc_mount); 748 749 if (error != 0) 750 goto bad; 751 752 #ifdef DEBUG 753 printf("fss%d: %s snapshot active\n", sc->sc_unit, sc->sc_mntname); 754 printf("fss%d: %u clusters of %u, %u cache slots, %u indir clusters\n", 755 sc->sc_unit, sc->sc_clcount, FSS_CLSIZE(sc), 756 sc->sc_cache_size, sc->sc_indir_size); 757 #endif 758 759 return 0; 760 761 bad: 762 fss_softc_free(sc); 763 if (sc->sc_bs_vp != NULL) { 764 if (sc->sc_flags & FSS_PERSISTENT) 765 vn_close(sc->sc_bs_vp, FREAD, l->l_cred); 766 else 767 vn_close(sc->sc_bs_vp, FREAD|FWRITE, l->l_cred); 768 } 769 sc->sc_bs_vp = NULL; 770 771 return error; 772 } 773 774 /* 775 * Delete a snapshot. 776 */ 777 static int 778 fss_delete_snapshot(struct fss_softc *sc, struct lwp *l) 779 { 780 int s; 781 782 if ((sc->sc_flags & FSS_PERSISTENT) == 0) 783 fscow_disestablish(sc->sc_mount, fss_copy_on_write, sc); 784 785 FSS_LOCK(sc, s); 786 sc->sc_flags &= ~(FSS_ACTIVE|FSS_ERROR); 787 sc->sc_mount = NULL; 788 sc->sc_bdev = NODEV; 789 FSS_UNLOCK(sc, s); 790 791 fss_softc_free(sc); 792 if (sc->sc_flags & FSS_PERSISTENT) 793 vn_close(sc->sc_bs_vp, FREAD, l->l_cred); 794 else 795 vn_close(sc->sc_bs_vp, FREAD|FWRITE, l->l_cred); 796 sc->sc_bs_vp = NULL; 797 sc->sc_flags &= ~FSS_PERSISTENT; 798 799 FSS_STAT_CLEAR(sc); 800 801 return 0; 802 } 803 804 /* 805 * A read from the snapshotted block device has completed. 806 */ 807 static void 808 fss_cluster_iodone(struct buf *bp) 809 { 810 int s; 811 struct fss_cache *scp = bp->b_private; 812 813 KASSERT(bp->b_vp == NULL); 814 815 FSS_LOCK(scp->fc_softc, s); 816 817 if (bp->b_error != 0) 818 fss_error(scp->fc_softc, "fs read error %d", bp->b_error); 819 820 if (--scp->fc_xfercount == 0) 821 wakeup(&scp->fc_data); 822 823 FSS_UNLOCK(scp->fc_softc, s); 824 825 putiobuf(bp); 826 } 827 828 /* 829 * Read a cluster from the snapshotted block device to the cache. 830 */ 831 static void 832 fss_read_cluster(struct fss_softc *sc, u_int32_t cl) 833 { 834 int s, todo, len; 835 char *addr; 836 daddr_t dblk; 837 struct buf *bp; 838 struct fss_cache *scp, *scl; 839 840 /* 841 * Get a free cache slot. 842 */ 843 scl = sc->sc_cache+sc->sc_cache_size; 844 845 FSS_LOCK(sc, s); 846 847 restart: 848 if (isset(sc->sc_copied, cl) || !FSS_ISVALID(sc)) { 849 FSS_UNLOCK(sc, s); 850 return; 851 } 852 853 for (scp = sc->sc_cache; scp < scl; scp++) 854 if (scp->fc_type != FSS_CACHE_FREE && 855 scp->fc_cluster == cl) { 856 ltsleep(&scp->fc_type, PRIBIO, "cowwait2", 0, 857 &sc->sc_slock); 858 goto restart; 859 } 860 861 for (scp = sc->sc_cache; scp < scl; scp++) 862 if (scp->fc_type == FSS_CACHE_FREE) { 863 scp->fc_type = FSS_CACHE_BUSY; 864 scp->fc_cluster = cl; 865 break; 866 } 867 if (scp >= scl) { 868 FSS_STAT_INC(sc, cow_cache_full); 869 ltsleep(&sc->sc_cache, PRIBIO, "cowwait3", 0, &sc->sc_slock); 870 goto restart; 871 } 872 873 FSS_UNLOCK(sc, s); 874 875 /* 876 * Start the read. 877 */ 878 FSS_STAT_INC(sc, cow_copied); 879 880 dblk = btodb(FSS_CLTOB(sc, cl)); 881 addr = scp->fc_data; 882 if (cl == sc->sc_clcount-1) { 883 todo = sc->sc_clresid; 884 memset((char *)addr + todo, 0, FSS_CLSIZE(sc) - todo); 885 } else 886 todo = FSS_CLSIZE(sc); 887 while (todo > 0) { 888 len = todo; 889 if (len > MAXPHYS) 890 len = MAXPHYS; 891 892 bp = getiobuf(NULL, true); 893 bp->b_flags = B_READ; 894 bp->b_bcount = len; 895 bp->b_bufsize = bp->b_bcount; 896 bp->b_error = 0; 897 bp->b_data = addr; 898 bp->b_blkno = dblk; 899 bp->b_proc = NULL; 900 bp->b_dev = sc->sc_bdev; 901 bp->b_private = scp; 902 bp->b_iodone = fss_cluster_iodone; 903 904 bdev_strategy(bp); 905 906 FSS_LOCK(sc, s); 907 scp->fc_xfercount++; 908 FSS_UNLOCK(sc, s); 909 910 dblk += btodb(len); 911 addr += len; 912 todo -= len; 913 } 914 915 /* 916 * Wait for all read requests to complete. 917 */ 918 FSS_LOCK(sc, s); 919 while (scp->fc_xfercount > 0) 920 ltsleep(&scp->fc_data, PRIBIO, "cowwait", 0, &sc->sc_slock); 921 922 scp->fc_type = FSS_CACHE_VALID; 923 setbit(sc->sc_copied, scp->fc_cluster); 924 FSS_UNLOCK(sc, s); 925 926 wakeup(&sc->sc_bs_lwp); 927 } 928 929 /* 930 * Read/write clusters from/to backing store. 931 * For persistent snapshots must be called with cl == 0. off is the 932 * offset into the snapshot. 933 */ 934 static int 935 fss_bs_io(struct fss_softc *sc, fss_io_type rw, 936 u_int32_t cl, off_t off, int len, void *data) 937 { 938 int error; 939 940 off += FSS_CLTOB(sc, cl); 941 942 vn_lock(sc->sc_bs_vp, LK_EXCLUSIVE|LK_RETRY); 943 944 error = vn_rdwr((rw == FSS_READ ? UIO_READ : UIO_WRITE), sc->sc_bs_vp, 945 data, len, off, UIO_SYSSPACE, IO_UNIT|IO_NODELOCKED, 946 sc->sc_bs_lwp->l_cred, NULL, NULL); 947 if (error == 0) { 948 mutex_enter(&sc->sc_bs_vp->v_interlock); 949 error = VOP_PUTPAGES(sc->sc_bs_vp, trunc_page(off), 950 round_page(off+len), PGO_CLEANIT|PGO_SYNCIO|PGO_FREE); 951 } 952 953 VOP_UNLOCK(sc->sc_bs_vp, 0); 954 955 return error; 956 } 957 958 /* 959 * Get a pointer to the indirect slot for this cluster. 960 */ 961 static u_int32_t * 962 fss_bs_indir(struct fss_softc *sc, u_int32_t cl) 963 { 964 u_int32_t icl; 965 int ioff; 966 967 icl = cl/(FSS_CLSIZE(sc)/sizeof(u_int32_t)); 968 ioff = cl%(FSS_CLSIZE(sc)/sizeof(u_int32_t)); 969 970 if (sc->sc_indir_cur == icl) 971 return &sc->sc_indir_data[ioff]; 972 973 if (sc->sc_indir_dirty) { 974 FSS_STAT_INC(sc, indir_write); 975 if (fss_bs_io(sc, FSS_WRITE, sc->sc_indir_cur, 0, 976 FSS_CLSIZE(sc), (void *)sc->sc_indir_data) != 0) 977 return NULL; 978 setbit(sc->sc_indir_valid, sc->sc_indir_cur); 979 } 980 981 sc->sc_indir_dirty = 0; 982 sc->sc_indir_cur = icl; 983 984 if (isset(sc->sc_indir_valid, sc->sc_indir_cur)) { 985 FSS_STAT_INC(sc, indir_read); 986 if (fss_bs_io(sc, FSS_READ, sc->sc_indir_cur, 0, 987 FSS_CLSIZE(sc), (void *)sc->sc_indir_data) != 0) 988 return NULL; 989 } else 990 memset(sc->sc_indir_data, 0, FSS_CLSIZE(sc)); 991 992 return &sc->sc_indir_data[ioff]; 993 } 994 995 /* 996 * The kernel thread (one for every active snapshot). 997 * 998 * After wakeup it cleans the cache and runs the I/O requests. 999 */ 1000 static void 1001 fss_bs_thread(void *arg) 1002 { 1003 int error, len, nfreed, nio, s; 1004 long off; 1005 char *addr; 1006 u_int32_t c, cl, ch, *indirp; 1007 struct buf *bp, *nbp; 1008 struct fss_softc *sc; 1009 struct fss_cache *scp, *scl; 1010 1011 sc = arg; 1012 1013 scl = sc->sc_cache+sc->sc_cache_size; 1014 1015 nbp = getiobuf(NULL, true); 1016 1017 nfreed = nio = 1; /* Dont sleep the first time */ 1018 1019 FSS_LOCK(sc, s); 1020 1021 for (;;) { 1022 if (nfreed == 0 && nio == 0) 1023 ltsleep(&sc->sc_bs_lwp, PVM-1, "fssbs", 0, 1024 &sc->sc_slock); 1025 1026 if ((sc->sc_flags & FSS_BS_THREAD) == 0) { 1027 sc->sc_bs_lwp = NULL; 1028 wakeup(&sc->sc_bs_lwp); 1029 1030 FSS_UNLOCK(sc, s); 1031 1032 putiobuf(nbp); 1033 #ifdef FSS_STATISTICS 1034 if ((sc->sc_flags & FSS_PERSISTENT) == 0) { 1035 printf("fss%d: cow called %" PRId64 " times," 1036 " copied %" PRId64 " clusters," 1037 " cache full %" PRId64 " times\n", 1038 sc->sc_unit, 1039 FSS_STAT_VAL(sc, cow_calls), 1040 FSS_STAT_VAL(sc, cow_copied), 1041 FSS_STAT_VAL(sc, cow_cache_full)); 1042 printf("fss%d: %" PRId64 " indir reads," 1043 " %" PRId64 " indir writes\n", 1044 sc->sc_unit, 1045 FSS_STAT_VAL(sc, indir_read), 1046 FSS_STAT_VAL(sc, indir_write)); 1047 } 1048 #endif /* FSS_STATISTICS */ 1049 kthread_exit(0); 1050 } 1051 1052 /* 1053 * Process I/O requests (persistent) 1054 */ 1055 1056 if (sc->sc_flags & FSS_PERSISTENT) { 1057 nfreed = nio = 0; 1058 1059 if ((bp = BUFQ_GET(sc->sc_bufq)) == NULL) 1060 continue; 1061 1062 nio++; 1063 1064 if (FSS_ISVALID(sc)) { 1065 FSS_UNLOCK(sc, s); 1066 1067 error = fss_bs_io(sc, FSS_READ, 0, 1068 dbtob(bp->b_blkno), bp->b_bcount, 1069 bp->b_data); 1070 1071 FSS_LOCK(sc, s); 1072 } else 1073 error = ENXIO; 1074 1075 if (error) { 1076 bp->b_error = error; 1077 bp->b_resid = bp->b_bcount; 1078 } else 1079 bp->b_resid = 0; 1080 1081 biodone(bp); 1082 1083 continue; 1084 } 1085 1086 /* 1087 * Clean the cache 1088 */ 1089 nfreed = 0; 1090 for (scp = sc->sc_cache; scp < scl; scp++) { 1091 if (scp->fc_type != FSS_CACHE_VALID) 1092 continue; 1093 1094 FSS_UNLOCK(sc, s); 1095 1096 indirp = fss_bs_indir(sc, scp->fc_cluster); 1097 if (indirp != NULL) { 1098 error = fss_bs_io(sc, FSS_WRITE, sc->sc_clnext, 1099 0, FSS_CLSIZE(sc), scp->fc_data); 1100 } else 1101 error = EIO; 1102 1103 FSS_LOCK(sc, s); 1104 1105 if (error == 0) { 1106 *indirp = sc->sc_clnext++; 1107 sc->sc_indir_dirty = 1; 1108 } else 1109 fss_error(sc, "write bs error %d", error); 1110 1111 scp->fc_type = FSS_CACHE_FREE; 1112 nfreed++; 1113 wakeup(&scp->fc_type); 1114 } 1115 1116 if (nfreed) 1117 wakeup(&sc->sc_cache); 1118 1119 /* 1120 * Process I/O requests 1121 */ 1122 nio = 0; 1123 1124 if ((bp = BUFQ_GET(sc->sc_bufq)) == NULL) 1125 continue; 1126 1127 nio++; 1128 1129 if (!FSS_ISVALID(sc)) { 1130 bp->b_error = ENXIO; 1131 bp->b_resid = bp->b_bcount; 1132 biodone(bp); 1133 continue; 1134 } 1135 1136 /* 1137 * First read from the snapshotted block device. 1138 * XXX Split to only read those parts that have not 1139 * been saved to backing store? 1140 */ 1141 1142 FSS_UNLOCK(sc, s); 1143 1144 buf_init(nbp); 1145 nbp->b_flags = B_READ; 1146 nbp->b_bcount = bp->b_bcount; 1147 nbp->b_bufsize = bp->b_bcount; 1148 nbp->b_error = 0; 1149 nbp->b_data = bp->b_data; 1150 nbp->b_blkno = bp->b_blkno; 1151 nbp->b_proc = bp->b_proc; 1152 nbp->b_dev = sc->sc_bdev; 1153 SET(nbp->b_cflags, BC_BUSY); /* mark buffer busy */ 1154 1155 bdev_strategy(nbp); 1156 1157 if (biowait(nbp) != 0) { 1158 bp->b_resid = bp->b_bcount; 1159 bp->b_error = nbp->b_error; 1160 biodone(bp); 1161 FSS_LOCK(sc, s); 1162 continue; 1163 } 1164 1165 cl = FSS_BTOCL(sc, dbtob(bp->b_blkno)); 1166 off = FSS_CLOFF(sc, dbtob(bp->b_blkno)); 1167 ch = FSS_BTOCL(sc, dbtob(bp->b_blkno)+bp->b_bcount-1); 1168 bp->b_resid = bp->b_bcount; 1169 addr = bp->b_data; 1170 1171 FSS_LOCK(sc, s); 1172 1173 /* 1174 * Replace those parts that have been saved to backing store. 1175 */ 1176 1177 for (c = cl; c <= ch; 1178 c++, off = 0, bp->b_resid -= len, addr += len) { 1179 len = FSS_CLSIZE(sc)-off; 1180 if (len > bp->b_resid) 1181 len = bp->b_resid; 1182 1183 if (isclr(sc->sc_copied, c)) 1184 continue; 1185 1186 FSS_UNLOCK(sc, s); 1187 1188 indirp = fss_bs_indir(sc, c); 1189 1190 FSS_LOCK(sc, s); 1191 1192 if (indirp == NULL || *indirp == 0) { 1193 /* 1194 * Not on backing store. Either in cache 1195 * or hole in the snapshotted block device. 1196 */ 1197 for (scp = sc->sc_cache; scp < scl; scp++) 1198 if (scp->fc_type == FSS_CACHE_VALID && 1199 scp->fc_cluster == c) 1200 break; 1201 if (scp < scl) 1202 memcpy(addr, (char *)scp->fc_data+off, len); 1203 else 1204 memset(addr, 0, len); 1205 continue; 1206 } 1207 /* 1208 * Read from backing store. 1209 */ 1210 1211 FSS_UNLOCK(sc, s); 1212 1213 if ((error = fss_bs_io(sc, FSS_READ, *indirp, 1214 off, len, addr)) != 0) { 1215 bp->b_resid = bp->b_bcount; 1216 bp->b_error = error; 1217 FSS_LOCK(sc, s); 1218 break; 1219 } 1220 1221 FSS_LOCK(sc, s); 1222 1223 } 1224 1225 biodone(bp); 1226 } 1227 } 1228
Indexes created Wed Nov 11 00:26:22 UTC 2026