fss.c revision 1.9
1 /* $NetBSD: fss.c,v 1.9 2004/06/20 18:55:58 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 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the NetBSD 21 * Foundation, Inc. and its contributors. 22 * 4. Neither the name of The NetBSD Foundation nor the names of its 23 * contributors may be used to endorse or promote products derived 24 * from this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39 /* 40 * File system snapshot disk driver. 41 * 42 * Block/character interface to the snapshot of a mounted file system. 43 */ 44 45 #include <sys/cdefs.h> 46 __KERNEL_RCSID(0, "$NetBSD: fss.c,v 1.9 2004/06/20 18:55:58 hannken Exp $"); 47 48 #include "fss.h" 49 50 #include <sys/param.h> 51 #include <sys/systm.h> 52 #include <sys/namei.h> 53 #include <sys/proc.h> 54 #include <sys/errno.h> 55 #include <sys/buf.h> 56 #include <sys/malloc.h> 57 #include <sys/ioctl.h> 58 #include <sys/disklabel.h> 59 #include <sys/device.h> 60 #include <sys/disk.h> 61 #include <sys/stat.h> 62 #include <sys/mount.h> 63 #include <sys/vnode.h> 64 #include <sys/file.h> 65 #include <sys/uio.h> 66 #include <sys/conf.h> 67 #include <sys/kthread.h> 68 69 #include <miscfs/specfs/specdev.h> 70 71 #include <dev/fssvar.h> 72 73 #include <machine/stdarg.h> 74 75 #ifdef DEBUG 76 #define FSS_STATISTICS 77 #endif 78 79 #ifdef FSS_STATISTICS 80 struct fss_stat { 81 u_int64_t cow_calls; 82 u_int64_t cow_copied; 83 u_int64_t cow_cache_full; 84 u_int64_t indir_read; 85 u_int64_t indir_write; 86 }; 87 88 static struct fss_stat fss_stat[NFSS]; 89 90 #define FSS_STAT_INC(sc, field) \ 91 do { \ 92 fss_stat[sc->sc_unit].field++; \ 93 } while (0) 94 #define FSS_STAT_SET(sc, field, value) \ 95 do { \ 96 fss_stat[sc->sc_unit].field = value; \ 97 } while (0) 98 #define FSS_STAT_ADD(sc, field, value) \ 99 do { \ 100 fss_stat[sc->sc_unit].field += value; \ 101 } while (0) 102 #define FSS_STAT_VAL(sc, field) fss_stat[sc->sc_unit].field 103 #define FSS_STAT_CLEAR(sc) \ 104 do { \ 105 memset(&fss_stat[sc->sc_unit], 0, \ 106 sizeof(struct fss_stat)); \ 107 } while (0) 108 #else /* FSS_STATISTICS */ 109 #define FSS_STAT_INC(sc, field) 110 #define FSS_STAT_SET(sc, field, value) 111 #define FSS_STAT_ADD(sc, field, value) 112 #define FSS_STAT_CLEAR(sc) 113 #endif /* FSS_STATISTICS */ 114 115 static struct fss_softc fss_softc[NFSS]; 116 117 void fssattach(int); 118 119 dev_type_open(fss_open); 120 dev_type_close(fss_close); 121 dev_type_read(fss_read); 122 dev_type_write(fss_write); 123 dev_type_ioctl(fss_ioctl); 124 dev_type_strategy(fss_strategy); 125 dev_type_dump(fss_dump); 126 dev_type_size(fss_size); 127 128 static int fss_copy_on_write(void *, struct buf *); 129 static inline void fss_error(struct fss_softc *, const char *, ...); 130 static int fss_create_files(struct fss_softc *, struct fss_set *, 131 off_t *, struct proc *); 132 static int fss_create_snapshot(struct fss_softc *, struct fss_set *, 133 struct proc *); 134 static int fss_delete_snapshot(struct fss_softc *, struct proc *); 135 static int fss_softc_alloc(struct fss_softc *); 136 static void fss_softc_free(struct fss_softc *); 137 static void fss_cluster_iodone(struct buf *); 138 static void fss_read_cluster(struct fss_softc *, u_int32_t); 139 static int fss_write_cluster(struct fss_cache *, u_int32_t); 140 static void fss_bs_thread(void *); 141 static int fss_bmap(struct fss_softc *, off_t, int, 142 struct vnode **, daddr_t *, int *); 143 static int fss_bs_io(struct fss_softc *, fss_io_type, 144 u_int32_t, off_t, int, caddr_t); 145 static u_int32_t *fss_bs_indir(struct fss_softc *, u_int32_t); 146 147 const struct bdevsw fss_bdevsw = { 148 fss_open, fss_close, fss_strategy, fss_ioctl, 149 fss_dump, fss_size, D_DISK 150 }; 151 152 const struct cdevsw fss_cdevsw = { 153 fss_open, fss_close, fss_read, fss_write, fss_ioctl, 154 nostop, notty, nopoll, nommap, nokqfilter, D_DISK 155 }; 156 157 void 158 fssattach(int num) 159 { 160 int i; 161 struct fss_softc *sc; 162 163 for (i = 0; i < NFSS; i++) { 164 sc = &fss_softc[i]; 165 sc->sc_unit = i; 166 sc->sc_bdev = NODEV; 167 simple_lock_init(&sc->sc_slock); 168 bufq_alloc(&sc->sc_bufq, BUFQ_FCFS|BUFQ_SORT_RAWBLOCK); 169 } 170 } 171 172 int 173 fss_open(dev_t dev, int flags, int mode, struct proc *p) 174 { 175 struct fss_softc *sc; 176 177 if ((sc = FSS_DEV_TO_SOFTC(dev)) == NULL) 178 return ENODEV; 179 180 return 0; 181 } 182 183 int 184 fss_close(dev_t dev, int flags, int mode, struct proc *p) 185 { 186 struct fss_softc *sc; 187 188 if ((sc = FSS_DEV_TO_SOFTC(dev)) == NULL) 189 return ENODEV; 190 191 return 0; 192 } 193 194 void 195 fss_strategy(struct buf *bp) 196 { 197 int s; 198 struct fss_softc *sc; 199 200 sc = FSS_DEV_TO_SOFTC(bp->b_dev); 201 202 FSS_LOCK(sc, s); 203 204 if ((bp->b_flags & B_READ) != B_READ || 205 sc == NULL || !FSS_ISVALID(sc)) { 206 207 FSS_UNLOCK(sc, s); 208 209 bp->b_error = (sc == NULL ? ENODEV : EROFS); 210 bp->b_flags |= B_ERROR; 211 bp->b_resid = bp->b_bcount; 212 biodone(bp); 213 return; 214 } 215 216 bp->b_rawblkno = bp->b_blkno; 217 BUFQ_PUT(&sc->sc_bufq, bp); 218 wakeup(&sc->sc_bs_proc); 219 220 FSS_UNLOCK(sc, s); 221 } 222 223 int 224 fss_read(dev_t dev, struct uio *uio, int flags) 225 { 226 return physio(fss_strategy, NULL, dev, B_READ, minphys, uio); 227 } 228 229 int 230 fss_write(dev_t dev, struct uio *uio, int flags) 231 { 232 return physio(fss_strategy, NULL, dev, B_WRITE, minphys, uio); 233 } 234 235 int 236 fss_ioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct proc *p) 237 { 238 int s, error; 239 struct fss_softc *sc; 240 struct fss_set *fss = (struct fss_set *)data; 241 struct fss_get *fsg = (struct fss_get *)data; 242 243 if ((sc = FSS_DEV_TO_SOFTC(dev)) == NULL) 244 return ENODEV; 245 246 FSS_LOCK(sc, s); 247 while ((sc->sc_flags & FSS_EXCL) == FSS_EXCL) { 248 error = ltsleep(sc, PRIBIO|PCATCH, "fsslock", 0, &sc->sc_slock); 249 if (error) { 250 FSS_UNLOCK(sc, s); 251 return error; 252 } 253 } 254 sc->sc_flags |= FSS_EXCL; 255 FSS_UNLOCK(sc, s); 256 257 error = EINVAL; 258 259 switch (cmd) { 260 case FSSIOCSET: 261 if ((flag & FWRITE) == 0) 262 error = EPERM; 263 else if ((sc->sc_flags & FSS_ACTIVE) != 0) 264 error = EBUSY; 265 else 266 error = fss_create_snapshot(sc, fss, p); 267 break; 268 269 case FSSIOCCLR: 270 if ((flag & FWRITE) == 0) 271 error = EPERM; 272 else if ((sc->sc_flags & FSS_ACTIVE) == 0) 273 error = ENXIO; 274 else 275 error = fss_delete_snapshot(sc, p); 276 break; 277 278 case FSSIOCGET: 279 switch (sc->sc_flags & (FSS_PERSISTENT | FSS_ACTIVE)) { 280 case FSS_ACTIVE: 281 memcpy(fsg->fsg_mount, sc->sc_mntname, MNAMELEN); 282 fsg->fsg_csize = FSS_CLSIZE(sc); 283 fsg->fsg_time = sc->sc_time; 284 fsg->fsg_mount_size = sc->sc_clcount; 285 fsg->fsg_bs_size = sc->sc_clnext; 286 error = 0; 287 break; 288 case FSS_PERSISTENT | FSS_ACTIVE: 289 memcpy(fsg->fsg_mount, sc->sc_mntname, MNAMELEN); 290 fsg->fsg_csize = 0; 291 fsg->fsg_time = sc->sc_time; 292 fsg->fsg_mount_size = 0; 293 fsg->fsg_bs_size = 0; 294 error = 0; 295 break; 296 default: 297 error = ENXIO; 298 break; 299 } 300 break; 301 } 302 303 FSS_LOCK(sc, s); 304 sc->sc_flags &= ~FSS_EXCL; 305 FSS_UNLOCK(sc, s); 306 wakeup(sc); 307 308 return error; 309 } 310 311 int 312 fss_size(dev_t dev) 313 { 314 return -1; 315 } 316 317 int 318 fss_dump(dev_t dev, daddr_t blkno, caddr_t va, size_t size) 319 { 320 return EROFS; 321 } 322 323 /* 324 * An error occurred reading or writing the snapshot or backing store. 325 * If it is the first error log to console. 326 * The caller holds the simplelock. 327 */ 328 static inline void 329 fss_error(struct fss_softc *sc, const char *fmt, ...) 330 { 331 va_list ap; 332 333 if ((sc->sc_flags & (FSS_ACTIVE|FSS_ERROR)) == FSS_ACTIVE) { 334 va_start(ap, fmt); 335 printf("fss%d: snapshot invalid: ", sc->sc_unit); 336 vprintf(fmt, ap); 337 printf("\n"); 338 va_end(ap); 339 } 340 if ((sc->sc_flags & FSS_ACTIVE) == FSS_ACTIVE) 341 sc->sc_flags |= FSS_ERROR; 342 } 343 344 /* 345 * Allocate the variable sized parts of the softc and 346 * fork the kernel thread. 347 * 348 * The fields sc_clcount, sc_clshift, sc_cache_size and sc_indir_size 349 * must be initialized. 350 */ 351 static int 352 fss_softc_alloc(struct fss_softc *sc) 353 { 354 int i, len, error; 355 356 len = (sc->sc_clcount+NBBY-1)/NBBY; 357 sc->sc_copied = malloc(len, M_TEMP, M_ZERO|M_WAITOK|M_CANFAIL); 358 if (sc->sc_copied == NULL) 359 return(ENOMEM); 360 361 len = sc->sc_cache_size*sizeof(struct fss_cache); 362 sc->sc_cache = malloc(len, M_TEMP, M_ZERO|M_WAITOK|M_CANFAIL); 363 if (sc->sc_cache == NULL) 364 return(ENOMEM); 365 366 len = FSS_CLSIZE(sc); 367 for (i = 0; i < sc->sc_cache_size; i++) { 368 sc->sc_cache[i].fc_type = FSS_CACHE_FREE; 369 sc->sc_cache[i].fc_softc = sc; 370 sc->sc_cache[i].fc_xfercount = 0; 371 sc->sc_cache[i].fc_data = malloc(len, M_TEMP, 372 M_WAITOK|M_CANFAIL); 373 if (sc->sc_cache[i].fc_data == NULL) 374 return(ENOMEM); 375 } 376 377 len = (sc->sc_indir_size+NBBY-1)/NBBY; 378 sc->sc_indir_valid = malloc(len, M_TEMP, M_ZERO|M_WAITOK|M_CANFAIL); 379 if (sc->sc_indir_valid == NULL) 380 return(ENOMEM); 381 382 len = FSS_CLSIZE(sc); 383 sc->sc_indir_data = malloc(len, M_TEMP, M_ZERO|M_WAITOK|M_CANFAIL); 384 if (sc->sc_indir_data == NULL) 385 return(ENOMEM); 386 387 if ((error = kthread_create1(fss_bs_thread, sc, &sc->sc_bs_proc, 388 "fssbs%d", sc->sc_unit)) != 0) 389 return error; 390 391 sc->sc_flags |= FSS_BS_THREAD; 392 return 0; 393 } 394 395 /* 396 * Free the variable sized parts of the softc. 397 */ 398 static void 399 fss_softc_free(struct fss_softc *sc) 400 { 401 int s, i; 402 403 if ((sc->sc_flags & FSS_BS_THREAD) != 0) { 404 FSS_LOCK(sc, s); 405 sc->sc_flags &= ~FSS_BS_THREAD; 406 wakeup(&sc->sc_bs_proc); 407 while (sc->sc_bs_proc != NULL) 408 ltsleep(&sc->sc_bs_proc, PRIBIO, "fssthread", 0, 409 &sc->sc_slock); 410 FSS_UNLOCK(sc, s); 411 } 412 413 if (sc->sc_copied != NULL) 414 free(sc->sc_copied, M_TEMP); 415 sc->sc_copied = NULL; 416 417 if (sc->sc_cache != NULL) { 418 for (i = 0; i < sc->sc_cache_size; i++) 419 if (sc->sc_cache[i].fc_data != NULL) 420 free(sc->sc_cache[i].fc_data, M_TEMP); 421 free(sc->sc_cache, M_TEMP); 422 } 423 sc->sc_cache = NULL; 424 425 if (sc->sc_indir_valid != NULL) 426 free(sc->sc_indir_valid, M_TEMP); 427 sc->sc_indir_valid = NULL; 428 429 if (sc->sc_indir_data != NULL) 430 free(sc->sc_indir_data, M_TEMP); 431 sc->sc_indir_data = NULL; 432 } 433 434 /* 435 * Check if an unmount is ok. If forced, set this snapshot into ERROR state. 436 */ 437 int 438 fss_umount_hook(struct mount *mp, int forced) 439 { 440 int i, s; 441 442 for (i = 0; i < NFSS; i++) { 443 FSS_LOCK(&fss_softc[i], s); 444 if ((fss_softc[i].sc_flags & FSS_ACTIVE) != 0 && 445 fss_softc[i].sc_mount == mp) { 446 if (forced) 447 fss_error(&fss_softc[i], "forced unmount"); 448 else { 449 FSS_UNLOCK(&fss_softc[i], s); 450 return EBUSY; 451 } 452 } 453 FSS_UNLOCK(&fss_softc[i], s); 454 } 455 456 return 0; 457 } 458 459 /* 460 * A buffer is written to the snapshotted block device. Copy to 461 * backing store if needed. 462 */ 463 static int 464 fss_copy_on_write(void *v, struct buf *bp) 465 { 466 int s; 467 u_int32_t cl, ch, c; 468 struct fss_softc *sc = v; 469 470 FSS_LOCK(sc, s); 471 if (!FSS_ISVALID(sc)) { 472 FSS_UNLOCK(sc, s); 473 return 0; 474 } 475 476 FSS_UNLOCK(sc, s); 477 478 FSS_STAT_INC(sc, cow_calls); 479 480 cl = FSS_BTOCL(sc, dbtob(bp->b_blkno)); 481 ch = FSS_BTOCL(sc, dbtob(bp->b_blkno)+bp->b_bcount-1); 482 483 for (c = cl; c <= ch; c++) 484 fss_read_cluster(sc, c); 485 486 return 0; 487 } 488 489 /* 490 * Lookup and open needed files. 491 * 492 * For file system internal snapshot initializes sc_mntname, sc_mount, 493 * sc_bs_vp and sc_time. 494 * 495 * Otherwise returns dev and size of the underlying block device. 496 * Initializes sc_mntname, sc_mount_vp, sc_bdev, sc_bs_vp and sc_mount 497 */ 498 static int 499 fss_create_files(struct fss_softc *sc, struct fss_set *fss, 500 off_t *bsize, struct proc *p) 501 { 502 int error, fsbsize; 503 struct timespec ts; 504 struct partinfo dpart; 505 struct vattr va; 506 struct nameidata nd; 507 508 /* 509 * Get the mounted file system. 510 */ 511 512 NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, fss->fss_mount, p); 513 if ((error = namei(&nd)) != 0) 514 return error; 515 516 if ((nd.ni_vp->v_flag & VROOT) != VROOT) { 517 vrele(nd.ni_vp); 518 return EINVAL; 519 } 520 521 sc->sc_mount = nd.ni_vp->v_mount; 522 memcpy(sc->sc_mntname, sc->sc_mount->mnt_stat.f_mntonname, MNAMELEN); 523 524 vrele(nd.ni_vp); 525 526 /* 527 * Check for file system internal snapshot. 528 */ 529 530 NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, fss->fss_bstore, p); 531 if ((error = namei(&nd)) != 0) 532 return error; 533 534 if (nd.ni_vp->v_type == VREG && nd.ni_vp->v_mount == sc->sc_mount) { 535 vrele(nd.ni_vp); 536 sc->sc_flags |= FSS_PERSISTENT; 537 538 NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, fss->fss_bstore, p); 539 if ((error = vn_open(&nd, FREAD, 0)) != 0) 540 return error; 541 sc->sc_bs_vp = nd.ni_vp; 542 543 fsbsize = sc->sc_bs_vp->v_mount->mnt_stat.f_iosize; 544 if (fsbsize & (fsbsize-1)) /* No power of two */ 545 return EINVAL; 546 for (sc->sc_bs_bshift = 1; sc->sc_bs_bshift < 32; 547 sc->sc_bs_bshift++) 548 if (FSS_FSBSIZE(sc) == fsbsize) 549 break; 550 if (sc->sc_bs_bshift >= 32) 551 return EINVAL; 552 sc->sc_bs_bmask = FSS_FSBSIZE(sc)-1; 553 554 sc->sc_clshift = 0; 555 556 error = VFS_SNAPSHOT(sc->sc_mount, sc->sc_bs_vp, &ts); 557 TIMESPEC_TO_TIMEVAL(&sc->sc_time, &ts); 558 559 VOP_UNLOCK(sc->sc_bs_vp, 0); 560 561 return error; 562 } 563 vrele(nd.ni_vp); 564 565 /* 566 * Get the block device it is mounted on. 567 */ 568 569 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, 570 sc->sc_mount->mnt_stat.f_mntfromname, p); 571 if ((error = namei(&nd)) != 0) 572 return error; 573 574 if (nd.ni_vp->v_type != VBLK) { 575 vrele(nd.ni_vp); 576 return EINVAL; 577 } 578 579 error = VOP_IOCTL(nd.ni_vp, DIOCGPART, &dpart, FREAD, p->p_ucred, p); 580 if (error) { 581 vrele(nd.ni_vp); 582 return error; 583 } 584 585 sc->sc_mount_vp = nd.ni_vp; 586 sc->sc_bdev = nd.ni_vp->v_rdev; 587 *bsize = (off_t)dpart.disklab->d_secsize*dpart.part->p_size; 588 vrele(nd.ni_vp); 589 590 /* 591 * Get the backing store 592 */ 593 594 NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, fss->fss_bstore, p); 595 if ((error = vn_open(&nd, FREAD|FWRITE, 0)) != 0) 596 return error; 597 VOP_UNLOCK(nd.ni_vp, 0); 598 599 sc->sc_bs_vp = nd.ni_vp; 600 601 if (nd.ni_vp->v_type != VREG && nd.ni_vp->v_type != VCHR) 602 return EINVAL; 603 604 if (sc->sc_bs_vp->v_type == VREG) { 605 error = VOP_GETATTR(sc->sc_bs_vp, &va, p->p_ucred, p); 606 if (error != 0) 607 return error; 608 sc->sc_bs_size = va.va_size; 609 fsbsize = sc->sc_bs_vp->v_mount->mnt_stat.f_iosize; 610 if (fsbsize & (fsbsize-1)) /* No power of two */ 611 return EINVAL; 612 for (sc->sc_bs_bshift = 1; sc->sc_bs_bshift < 32; 613 sc->sc_bs_bshift++) 614 if (FSS_FSBSIZE(sc) == fsbsize) 615 break; 616 if (sc->sc_bs_bshift >= 32) 617 return EINVAL; 618 sc->sc_bs_bmask = FSS_FSBSIZE(sc)-1; 619 sc->sc_flags |= FSS_BS_ALLOC; 620 } else { 621 sc->sc_bs_bshift = DEV_BSHIFT; 622 sc->sc_bs_bmask = FSS_FSBSIZE(sc)-1; 623 sc->sc_flags &= ~FSS_BS_ALLOC; 624 } 625 626 /* 627 * As all IO to from/to the backing store goes through 628 * VOP_STRATEGY() clean the buffer cache to prevent 629 * cache incoherencies. 630 */ 631 if ((error = vinvalbuf(sc->sc_bs_vp, V_SAVE, p->p_ucred, p, 0, 0)) != 0) 632 return error; 633 634 return 0; 635 } 636 637 /* 638 * Create a snapshot. 639 */ 640 static int 641 fss_create_snapshot(struct fss_softc *sc, struct fss_set *fss, struct proc *p) 642 { 643 int len, error; 644 u_int32_t csize; 645 off_t bsize; 646 647 /* 648 * Open needed files. 649 */ 650 if ((error = fss_create_files(sc, fss, &bsize, p)) != 0) 651 goto bad; 652 653 if (sc->sc_flags & FSS_PERSISTENT) { 654 fss_softc_alloc(sc); 655 sc->sc_flags |= FSS_ACTIVE; 656 return 0; 657 } 658 659 /* 660 * Set cluster size. Must be a power of two and 661 * a multiple of backing store block size. 662 */ 663 if (fss->fss_csize <= 0) 664 csize = MAXPHYS; 665 else 666 csize = fss->fss_csize; 667 if (bsize/csize > FSS_CLUSTER_MAX) 668 csize = bsize/FSS_CLUSTER_MAX+1; 669 670 for (sc->sc_clshift = sc->sc_bs_bshift; sc->sc_clshift < 32; 671 sc->sc_clshift++) 672 if (FSS_CLSIZE(sc) >= csize) 673 break; 674 if (sc->sc_clshift >= 32) { 675 error = EINVAL; 676 goto bad; 677 } 678 sc->sc_clmask = FSS_CLSIZE(sc)-1; 679 680 /* 681 * Set number of cache slots. 682 */ 683 if (FSS_CLSIZE(sc) <= 8192) 684 sc->sc_cache_size = 32; 685 else if (FSS_CLSIZE(sc) <= 65536) 686 sc->sc_cache_size = 8; 687 else 688 sc->sc_cache_size = 4; 689 690 /* 691 * Set number of clusters and size of last cluster. 692 */ 693 sc->sc_clcount = FSS_BTOCL(sc, bsize-1)+1; 694 sc->sc_clresid = FSS_CLOFF(sc, bsize-1)+1; 695 696 /* 697 * Set size of indirect table. 698 */ 699 len = sc->sc_clcount*sizeof(u_int32_t); 700 sc->sc_indir_size = FSS_BTOCL(sc, len)+1; 701 sc->sc_clnext = sc->sc_indir_size; 702 sc->sc_indir_cur = 0; 703 704 if ((error = fss_softc_alloc(sc)) != 0) 705 goto bad; 706 707 /* 708 * Activate the snapshot. 709 */ 710 711 if ((error = vfs_write_suspend(sc->sc_mount, PUSER|PCATCH, 0)) != 0) 712 goto bad; 713 714 microtime(&sc->sc_time); 715 716 if (error == 0) 717 error = vn_cow_establish(sc->sc_mount_vp, 718 fss_copy_on_write, sc); 719 if (error == 0) 720 sc->sc_flags |= FSS_ACTIVE; 721 722 vfs_write_resume(sc->sc_mount); 723 724 if (error != 0) 725 goto bad; 726 727 #ifdef DEBUG 728 printf("fss%d: %s snapshot active\n", sc->sc_unit, sc->sc_mntname); 729 printf("fss%d: %u clusters of %u, %u cache slots, %u indir clusters\n", 730 sc->sc_unit, sc->sc_clcount, FSS_CLSIZE(sc), 731 sc->sc_cache_size, sc->sc_indir_size); 732 #endif 733 734 return 0; 735 736 bad: 737 fss_softc_free(sc); 738 if (sc->sc_bs_vp != NULL) { 739 if (sc->sc_flags & FSS_PERSISTENT) 740 vn_close(sc->sc_bs_vp, FREAD, p->p_ucred, p); 741 else 742 vn_close(sc->sc_bs_vp, FREAD|FWRITE, p->p_ucred, p); 743 } 744 sc->sc_bs_vp = NULL; 745 746 return error; 747 } 748 749 /* 750 * Delete a snapshot. 751 */ 752 static int 753 fss_delete_snapshot(struct fss_softc *sc, struct proc *p) 754 { 755 int s; 756 757 if ((sc->sc_flags & FSS_PERSISTENT) == 0) 758 vn_cow_disestablish(sc->sc_mount_vp, fss_copy_on_write, sc); 759 760 FSS_LOCK(sc, s); 761 sc->sc_flags &= ~(FSS_ACTIVE|FSS_ERROR); 762 sc->sc_mount = NULL; 763 sc->sc_bdev = NODEV; 764 FSS_UNLOCK(sc, s); 765 766 fss_softc_free(sc); 767 if (sc->sc_flags & FSS_PERSISTENT) 768 vn_close(sc->sc_bs_vp, FREAD, p->p_ucred, p); 769 else 770 vn_close(sc->sc_bs_vp, FREAD|FWRITE, p->p_ucred, p); 771 sc->sc_bs_vp = NULL; 772 sc->sc_flags &= ~FSS_PERSISTENT; 773 774 FSS_STAT_CLEAR(sc); 775 776 return 0; 777 } 778 779 /* 780 * Get the block address and number of contiguous blocks. 781 * If the file contains a hole, try to allocate. 782 * Backing store is locked by caller. 783 */ 784 static int 785 fss_bmap(struct fss_softc *sc, off_t start, int len, 786 struct vnode **vpp, daddr_t *bnp, int *runp) 787 { 788 int l, s, error; 789 struct buf *bp, **bpp; 790 791 if ((sc->sc_bs_vp->v_mount->mnt_flag & MNT_SOFTDEP) != 0) 792 bpp = &bp; 793 else 794 bpp = NULL; 795 796 error = VOP_BMAP(sc->sc_bs_vp, FSS_BTOFSB(sc, start), vpp, bnp, runp); 797 if ((error == 0 && *bnp != (daddr_t)-1) || 798 (sc->sc_flags & FSS_BS_ALLOC) == 0) 799 goto out; 800 801 if (start+len >= sc->sc_bs_size) { 802 error = ENOSPC; 803 goto out; 804 } 805 806 for (l = 0; l < len; l += FSS_FSBSIZE(sc)) { 807 error = VOP_BALLOC(sc->sc_bs_vp, start+l, FSS_FSBSIZE(sc), 808 sc->sc_bs_proc->p_ucred, 0, bpp); 809 if (error) 810 goto out; 811 812 if (bpp == NULL) 813 continue; 814 815 s = splbio(); 816 simple_lock(&bp->b_interlock); 817 818 if (LIST_FIRST(&bp->b_dep) != NULL && bioops.io_start) 819 (*bioops.io_start)(bp); 820 if (LIST_FIRST(&bp->b_dep) != NULL && bioops.io_complete) 821 (*bioops.io_complete)(bp); 822 823 bp->b_flags |= B_INVAL; 824 simple_unlock(&bp->b_interlock); 825 splx(s); 826 827 brelse(bp); 828 } 829 830 error = VOP_BMAP(sc->sc_bs_vp, FSS_BTOFSB(sc, start), vpp, bnp, runp); 831 832 out: 833 834 if ((sc->sc_flags & FSS_PERSISTENT) == 0 && 835 error == 0 && *bnp == (daddr_t)-1) 836 error = ENOSPC; 837 838 return error; 839 } 840 841 /* 842 * A read from the snapshotted block device has completed. 843 */ 844 static void 845 fss_cluster_iodone(struct buf *bp) 846 { 847 int s; 848 struct fss_cache *scp = bp->b_private; 849 850 FSS_LOCK(scp->fc_softc, s); 851 852 if (bp->b_flags & B_EINTR) 853 fss_error(scp->fc_softc, "fs read interrupted"); 854 if (bp->b_flags & B_ERROR) 855 fss_error(scp->fc_softc, "fs read error %d", bp->b_error); 856 857 if (bp->b_vp != NULL) 858 brelvp(bp); 859 860 if (--scp->fc_xfercount == 0) 861 wakeup(&scp->fc_data); 862 863 FSS_UNLOCK(scp->fc_softc, s); 864 865 s = splbio(); 866 pool_put(&bufpool, bp); 867 splx(s); 868 } 869 870 /* 871 * Read a cluster from the snapshotted block device to the cache. 872 */ 873 static void 874 fss_read_cluster(struct fss_softc *sc, u_int32_t cl) 875 { 876 int s, todo, len; 877 caddr_t addr; 878 daddr_t dblk; 879 struct buf *bp; 880 struct fss_cache *scp, *scl; 881 882 /* 883 * Get a free cache slot. 884 */ 885 scl = sc->sc_cache+sc->sc_cache_size; 886 887 FSS_LOCK(sc, s); 888 889 restart: 890 if (isset(sc->sc_copied, cl) || !FSS_ISVALID(sc)) { 891 FSS_UNLOCK(sc, s); 892 return; 893 } 894 895 for (scp = sc->sc_cache; scp < scl; scp++) 896 if (scp->fc_type != FSS_CACHE_FREE && 897 scp->fc_cluster == cl) { 898 ltsleep(&scp->fc_type, PRIBIO, "cowwait2", 0, 899 &sc->sc_slock); 900 goto restart; 901 } 902 903 for (scp = sc->sc_cache; scp < scl; scp++) 904 if (scp->fc_type == FSS_CACHE_FREE) { 905 scp->fc_type = FSS_CACHE_BUSY; 906 scp->fc_cluster = cl; 907 break; 908 } 909 if (scp >= scl) { 910 FSS_STAT_INC(sc, cow_cache_full); 911 ltsleep(&sc->sc_cache, PRIBIO, "cowwait3", 0, &sc->sc_slock); 912 goto restart; 913 } 914 915 FSS_UNLOCK(sc, s); 916 917 /* 918 * Start the read. 919 */ 920 FSS_STAT_INC(sc, cow_copied); 921 922 dblk = btodb(FSS_CLTOB(sc, cl)); 923 addr = scp->fc_data; 924 if (cl == sc->sc_clcount-1) { 925 todo = sc->sc_clresid; 926 memset(addr+todo, 0, FSS_CLSIZE(sc)-todo); 927 } else 928 todo = FSS_CLSIZE(sc); 929 while (todo > 0) { 930 len = todo; 931 if (len > MAXPHYS) 932 len = MAXPHYS; 933 934 s = splbio(); 935 bp = pool_get(&bufpool, PR_WAITOK); 936 splx(s); 937 938 BUF_INIT(bp); 939 bp->b_flags = B_READ|B_CALL; 940 bp->b_bcount = len; 941 bp->b_bufsize = bp->b_bcount; 942 bp->b_error = 0; 943 bp->b_data = addr; 944 bp->b_blkno = bp->b_rawblkno = dblk; 945 bp->b_proc = NULL; 946 bp->b_dev = sc->sc_bdev; 947 bp->b_vp = NULLVP; 948 bp->b_private = scp; 949 bp->b_iodone = fss_cluster_iodone; 950 951 DEV_STRATEGY(bp); 952 953 FSS_LOCK(sc, s); 954 scp->fc_xfercount++; 955 FSS_UNLOCK(sc, s); 956 957 dblk += btodb(len); 958 addr += len; 959 todo -= len; 960 } 961 962 /* 963 * Wait for all read requests to complete. 964 */ 965 FSS_LOCK(sc, s); 966 while (scp->fc_xfercount > 0) 967 ltsleep(&scp->fc_data, PRIBIO, "cowwait", 0, &sc->sc_slock); 968 969 scp->fc_type = FSS_CACHE_VALID; 970 setbit(sc->sc_copied, scp->fc_cluster); 971 FSS_UNLOCK(sc, s); 972 973 wakeup(&sc->sc_bs_proc); 974 } 975 976 /* 977 * Write a cluster from the cache to the backing store. 978 */ 979 static int 980 fss_write_cluster(struct fss_cache *scp, u_int32_t cl) 981 { 982 int s, error, todo, len, nra; 983 daddr_t nbn; 984 caddr_t addr; 985 off_t pos; 986 struct buf *bp; 987 struct vnode *vp; 988 struct fss_softc *sc; 989 990 error = 0; 991 sc = scp->fc_softc; 992 993 pos = FSS_CLTOB(sc, cl); 994 addr = scp->fc_data; 995 todo = FSS_CLSIZE(sc); 996 997 vn_lock(sc->sc_bs_vp, LK_EXCLUSIVE|LK_RETRY); 998 simple_lock(&sc->sc_bs_vp->v_interlock); 999 error = VOP_PUTPAGES(sc->sc_bs_vp, trunc_page(pos), 1000 round_page(pos+todo), PGO_CLEANIT|PGO_SYNCIO|PGO_FREE); 1001 1002 while (error == 0 && todo > 0) { 1003 error = fss_bmap(sc, pos, todo, &vp, &nbn, &nra); 1004 if (error) 1005 break; 1006 1007 len = FSS_FSBTOB(sc, nra+1)-FSS_FSBOFF(sc, pos); 1008 if (len > todo) 1009 len = todo; 1010 1011 s = splbio(); 1012 bp = pool_get(&bufpool, PR_WAITOK); 1013 splx(s); 1014 1015 BUF_INIT(bp); 1016 bp->b_flags = B_CALL; 1017 bp->b_bcount = len; 1018 bp->b_bufsize = bp->b_bcount; 1019 bp->b_error = 0; 1020 bp->b_data = addr; 1021 bp->b_blkno = bp->b_rawblkno = nbn+btodb(FSS_FSBOFF(sc, pos)); 1022 bp->b_proc = NULL; 1023 bp->b_vp = NULLVP; 1024 bp->b_private = scp; 1025 bp->b_iodone = fss_cluster_iodone; 1026 bgetvp(vp, bp); 1027 bp->b_vp->v_numoutput++; 1028 1029 BIO_SETPRIO(bp, BPRIO_TIMECRITICAL); 1030 VOP_STRATEGY(vp, bp); 1031 1032 FSS_LOCK(sc, s); 1033 scp->fc_xfercount++; 1034 FSS_UNLOCK(sc, s); 1035 1036 pos += len; 1037 addr += len; 1038 todo -= len; 1039 } 1040 1041 /* 1042 * Wait for all write requests to complete. 1043 */ 1044 FSS_LOCK(sc, s); 1045 while (scp->fc_xfercount > 0) 1046 ltsleep(&scp->fc_data, PRIBIO, "bswwait", 0, &sc->sc_slock); 1047 FSS_UNLOCK(sc, s); 1048 1049 VOP_UNLOCK(sc->sc_bs_vp, 0); 1050 1051 return error; 1052 } 1053 1054 /* 1055 * Read/write clusters from/to backing store. 1056 * For persistent snapshots must be called with cl == 0. off is the 1057 * offset into the snapshot. 1058 */ 1059 static int 1060 fss_bs_io(struct fss_softc *sc, fss_io_type rw, 1061 u_int32_t cl, off_t off, int len, caddr_t data) 1062 { 1063 int s, error, todo, count, nra; 1064 off_t pos; 1065 daddr_t nbn; 1066 struct buf *bp; 1067 struct vnode *vp; 1068 1069 todo = len; 1070 pos = FSS_CLTOB(sc, cl)+off; 1071 error = 0; 1072 1073 vn_lock(sc->sc_bs_vp, LK_EXCLUSIVE|LK_RETRY); 1074 simple_lock(&sc->sc_bs_vp->v_interlock); 1075 error = VOP_PUTPAGES(sc->sc_bs_vp, trunc_page(pos), 1076 round_page(pos+todo), PGO_CLEANIT|PGO_SYNCIO|PGO_FREE); 1077 1078 while (error == 0 && todo > 0) { 1079 error = fss_bmap(sc, pos, todo, &vp, &nbn, &nra); 1080 if (error) 1081 break; 1082 1083 count = FSS_FSBTOB(sc, nra+1)-FSS_FSBOFF(sc, pos); 1084 if (count > todo) 1085 count = todo; 1086 1087 if (nbn == (daddr_t)-1) { 1088 bzero(data, count); 1089 todo -= count; 1090 data += count; 1091 pos += count; 1092 continue; 1093 } 1094 1095 s = splbio(); 1096 bp = pool_get(&bufpool, PR_WAITOK); 1097 splx(s); 1098 1099 BUF_INIT(bp); 1100 bp->b_flags = (rw == FSS_READ ? B_READ : 0); 1101 bp->b_bcount = count; 1102 bp->b_bufsize = bp->b_bcount; 1103 bp->b_error = 0; 1104 bp->b_data = data; 1105 bp->b_blkno = bp->b_rawblkno = nbn+btodb(FSS_FSBOFF(sc, pos)); 1106 bp->b_proc = NULL; 1107 bp->b_vp = NULLVP; 1108 bgetvp(vp, bp); 1109 if ((bp->b_flags & B_READ) == 0) 1110 bp->b_vp->v_numoutput++; 1111 1112 if ((bp->b_flags & B_READ) == 0 || cl < sc->sc_indir_size) 1113 BIO_SETPRIO(bp, BPRIO_TIMECRITICAL); 1114 VOP_STRATEGY(vp, bp); 1115 1116 error = biowait(bp); 1117 1118 if (bp->b_vp != NULL) 1119 brelvp(bp); 1120 1121 s = splbio(); 1122 pool_put(&bufpool, bp); 1123 splx(s); 1124 1125 if (error) 1126 break; 1127 1128 todo -= count; 1129 data += count; 1130 pos += count; 1131 } 1132 1133 VOP_UNLOCK(sc->sc_bs_vp, 0); 1134 1135 return error; 1136 } 1137 1138 /* 1139 * Get a pointer to the indirect slot for this cluster. 1140 */ 1141 static u_int32_t * 1142 fss_bs_indir(struct fss_softc *sc, u_int32_t cl) 1143 { 1144 u_int32_t icl; 1145 int ioff; 1146 1147 icl = cl/(FSS_CLSIZE(sc)/sizeof(u_int32_t)); 1148 ioff = cl%(FSS_CLSIZE(sc)/sizeof(u_int32_t)); 1149 1150 if (sc->sc_indir_cur == icl) 1151 return &sc->sc_indir_data[ioff]; 1152 1153 if (sc->sc_indir_dirty) { 1154 FSS_STAT_INC(sc, indir_write); 1155 if (fss_bs_io(sc, FSS_WRITE, sc->sc_indir_cur, 0, 1156 FSS_CLSIZE(sc), (caddr_t)sc->sc_indir_data) != 0) 1157 return NULL; 1158 setbit(sc->sc_indir_valid, sc->sc_indir_cur); 1159 } 1160 1161 sc->sc_indir_dirty = 0; 1162 sc->sc_indir_cur = icl; 1163 1164 if (isset(sc->sc_indir_valid, sc->sc_indir_cur)) { 1165 FSS_STAT_INC(sc, indir_read); 1166 if (fss_bs_io(sc, FSS_READ, sc->sc_indir_cur, 0, 1167 FSS_CLSIZE(sc), (caddr_t)sc->sc_indir_data) != 0) 1168 return NULL; 1169 } else 1170 memset(sc->sc_indir_data, 0, FSS_CLSIZE(sc)); 1171 1172 return &sc->sc_indir_data[ioff]; 1173 } 1174 1175 /* 1176 * The kernel thread (one for every active snapshot). 1177 * 1178 * After wakeup it cleans the cache and runs the I/O requests. 1179 */ 1180 static void 1181 fss_bs_thread(void *arg) 1182 { 1183 int error, len, nfreed, nio, s; 1184 long off; 1185 caddr_t addr; 1186 u_int32_t c, cl, ch, *indirp; 1187 struct buf *bp, *nbp; 1188 struct fss_softc *sc; 1189 struct fss_cache *scp, *scl; 1190 1191 sc = arg; 1192 1193 scl = sc->sc_cache+sc->sc_cache_size; 1194 1195 s = splbio(); 1196 nbp = pool_get(&bufpool, PR_WAITOK); 1197 splx(s); 1198 1199 nfreed = nio = 1; /* Dont sleep the first time */ 1200 1201 FSS_LOCK(sc, s); 1202 1203 for (;;) { 1204 if (nfreed == 0 && nio == 0) 1205 ltsleep(&sc->sc_bs_proc, PVM-1, "fssbs", 0, 1206 &sc->sc_slock); 1207 1208 if ((sc->sc_flags & FSS_BS_THREAD) == 0) { 1209 sc->sc_bs_proc = NULL; 1210 wakeup(&sc->sc_bs_proc); 1211 1212 FSS_UNLOCK(sc, s); 1213 1214 s = splbio(); 1215 pool_put(&bufpool, nbp); 1216 splx(s); 1217 #ifdef FSS_STATISTICS 1218 if ((sc->sc_flags & FSS_PERSISTENT) == 0) { 1219 printf("fss%d: cow called %" PRId64 " times," 1220 " copied %" PRId64 " clusters," 1221 " cache full %" PRId64 " times\n", 1222 sc->sc_unit, 1223 FSS_STAT_VAL(sc, cow_calls), 1224 FSS_STAT_VAL(sc, cow_copied), 1225 FSS_STAT_VAL(sc, cow_cache_full)); 1226 printf("fss%d: %" PRId64 " indir reads," 1227 " %" PRId64 " indir writes\n", 1228 sc->sc_unit, 1229 FSS_STAT_VAL(sc, indir_read), 1230 FSS_STAT_VAL(sc, indir_write)); 1231 } 1232 #endif /* FSS_STATISTICS */ 1233 kthread_exit(0); 1234 } 1235 1236 /* 1237 * Process I/O requests (persistent) 1238 */ 1239 1240 if (sc->sc_flags & FSS_PERSISTENT) { 1241 nfreed = nio = 0; 1242 1243 if ((bp = BUFQ_GET(&sc->sc_bufq)) == NULL) 1244 continue; 1245 1246 nio++; 1247 1248 if (FSS_ISVALID(sc)) { 1249 FSS_UNLOCK(sc, s); 1250 1251 error = fss_bs_io(sc, FSS_READ, 0, 1252 dbtob(bp->b_blkno), bp->b_bcount, 1253 bp->b_data); 1254 1255 FSS_LOCK(sc, s); 1256 } else 1257 error = ENXIO; 1258 1259 if (error) { 1260 bp->b_error = error; 1261 bp->b_flags |= B_ERROR; 1262 bp->b_resid = bp->b_bcount; 1263 } 1264 biodone(bp); 1265 1266 continue; 1267 } 1268 1269 /* 1270 * Clean the cache 1271 */ 1272 nfreed = 0; 1273 for (scp = sc->sc_cache; scp < scl; scp++) { 1274 if (scp->fc_type != FSS_CACHE_VALID) 1275 continue; 1276 1277 FSS_UNLOCK(sc, s); 1278 1279 indirp = fss_bs_indir(sc, scp->fc_cluster); 1280 if (indirp != NULL) { 1281 error = fss_write_cluster(scp, sc->sc_clnext); 1282 } else 1283 error = EIO; 1284 1285 FSS_LOCK(sc, s); 1286 1287 if (error == 0) { 1288 *indirp = sc->sc_clnext++; 1289 sc->sc_indir_dirty = 1; 1290 } else 1291 fss_error(sc, "write bs error %d", error); 1292 1293 scp->fc_type = FSS_CACHE_FREE; 1294 nfreed++; 1295 wakeup(&scp->fc_type); 1296 } 1297 1298 if (nfreed) 1299 wakeup(&sc->sc_cache); 1300 1301 /* 1302 * Process I/O requests 1303 */ 1304 nio = 0; 1305 1306 if ((bp = BUFQ_GET(&sc->sc_bufq)) == NULL) 1307 continue; 1308 1309 nio++; 1310 1311 if (!FSS_ISVALID(sc)) { 1312 bp->b_error = ENXIO; 1313 bp->b_flags |= B_ERROR; 1314 bp->b_resid = bp->b_bcount; 1315 biodone(bp); 1316 continue; 1317 } 1318 1319 /* 1320 * First read from the snapshotted block device. 1321 * XXX Split to only read those parts that have not 1322 * been saved to backing store? 1323 */ 1324 1325 FSS_UNLOCK(sc, s); 1326 1327 BUF_INIT(nbp); 1328 nbp->b_flags = B_READ; 1329 nbp->b_bcount = bp->b_bcount; 1330 nbp->b_bufsize = bp->b_bcount; 1331 nbp->b_error = 0; 1332 nbp->b_data = bp->b_data; 1333 nbp->b_blkno = nbp->b_rawblkno = bp->b_blkno; 1334 nbp->b_proc = bp->b_proc; 1335 nbp->b_dev = sc->sc_bdev; 1336 nbp->b_vp = NULLVP; 1337 1338 DEV_STRATEGY(nbp); 1339 1340 if (biowait(nbp) != 0) { 1341 bp->b_resid = bp->b_bcount; 1342 bp->b_error = nbp->b_error; 1343 bp->b_flags |= B_ERROR; 1344 biodone(bp); 1345 continue; 1346 } 1347 1348 cl = FSS_BTOCL(sc, dbtob(bp->b_blkno)); 1349 off = FSS_CLOFF(sc, dbtob(bp->b_blkno)); 1350 ch = FSS_BTOCL(sc, dbtob(bp->b_blkno)+bp->b_bcount-1); 1351 bp->b_resid = bp->b_bcount; 1352 addr = bp->b_data; 1353 1354 FSS_LOCK(sc, s); 1355 1356 /* 1357 * Replace those parts that have been saved to backing store. 1358 */ 1359 1360 for (c = cl; c <= ch; 1361 c++, off = 0, bp->b_resid -= len, addr += len) { 1362 len = FSS_CLSIZE(sc)-off; 1363 if (len > bp->b_resid) 1364 len = bp->b_resid; 1365 1366 if (isclr(sc->sc_copied, c)) 1367 continue; 1368 1369 FSS_UNLOCK(sc, s); 1370 1371 indirp = fss_bs_indir(sc, c); 1372 1373 FSS_LOCK(sc, s); 1374 1375 if (indirp == NULL || *indirp == 0) { 1376 /* 1377 * Not on backing store. Either in cache 1378 * or hole in the snapshotted block device. 1379 */ 1380 for (scp = sc->sc_cache; scp < scl; scp++) 1381 if (scp->fc_type == FSS_CACHE_VALID && 1382 scp->fc_cluster == c) 1383 break; 1384 if (scp < scl) 1385 memcpy(addr, scp->fc_data+off, len); 1386 else 1387 memset(addr, 0, len); 1388 continue; 1389 } 1390 /* 1391 * Read from backing store. 1392 */ 1393 1394 FSS_UNLOCK(sc, s); 1395 1396 if ((error = fss_bs_io(sc, FSS_READ, *indirp, 1397 off, len, addr)) != 0) { 1398 bp->b_resid = bp->b_bcount; 1399 bp->b_error = error; 1400 bp->b_flags |= B_ERROR; 1401 break; 1402 } 1403 1404 FSS_LOCK(sc, s); 1405 1406 } 1407 1408 biodone(bp); 1409 } 1410 } 1411
Indexes created Wed Nov 11 00:26:22 UTC 2026