fss.c revision 1.13
1 /* $NetBSD: fss.c,v 1.13 2005/02/27 00:26:58 perry 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 1.13 2005/02/27 00:26:58 perry 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, bits, 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 bits = sizeof(sc->sc_bs_bshift)*NBBY; 545 for (sc->sc_bs_bshift = 1; sc->sc_bs_bshift < bits; 546 sc->sc_bs_bshift++) 547 if (FSS_FSBSIZE(sc) == fsbsize) 548 break; 549 if (sc->sc_bs_bshift >= bits) { 550 VOP_UNLOCK(sc->sc_bs_vp, 0); 551 return EINVAL; 552 } 553 554 sc->sc_bs_bmask = FSS_FSBSIZE(sc)-1; 555 sc->sc_clshift = 0; 556 557 error = VFS_SNAPSHOT(sc->sc_mount, sc->sc_bs_vp, &ts); 558 TIMESPEC_TO_TIMEVAL(&sc->sc_time, &ts); 559 560 VOP_UNLOCK(sc->sc_bs_vp, 0); 561 562 return error; 563 } 564 vrele(nd.ni_vp); 565 566 /* 567 * Get the block device it is mounted on. 568 */ 569 570 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, 571 sc->sc_mount->mnt_stat.f_mntfromname, p); 572 if ((error = namei(&nd)) != 0) 573 return error; 574 575 if (nd.ni_vp->v_type != VBLK) { 576 vrele(nd.ni_vp); 577 return EINVAL; 578 } 579 580 error = VOP_IOCTL(nd.ni_vp, DIOCGPART, &dpart, FREAD, p->p_ucred, p); 581 if (error) { 582 vrele(nd.ni_vp); 583 return error; 584 } 585 586 sc->sc_mount_vp = nd.ni_vp; 587 sc->sc_bdev = nd.ni_vp->v_rdev; 588 *bsize = (off_t)dpart.disklab->d_secsize*dpart.part->p_size; 589 vrele(nd.ni_vp); 590 591 /* 592 * Get the backing store 593 */ 594 595 NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, fss->fss_bstore, p); 596 if ((error = vn_open(&nd, FREAD|FWRITE, 0)) != 0) 597 return error; 598 VOP_UNLOCK(nd.ni_vp, 0); 599 600 sc->sc_bs_vp = nd.ni_vp; 601 602 if (nd.ni_vp->v_type != VREG && nd.ni_vp->v_type != VCHR) 603 return EINVAL; 604 605 if (sc->sc_bs_vp->v_type == VREG) { 606 error = VOP_GETATTR(sc->sc_bs_vp, &va, p->p_ucred, p); 607 if (error != 0) 608 return error; 609 sc->sc_bs_size = va.va_size; 610 fsbsize = sc->sc_bs_vp->v_mount->mnt_stat.f_iosize; 611 if (fsbsize & (fsbsize-1)) /* No power of two */ 612 return EINVAL; 613 for (sc->sc_bs_bshift = 1; sc->sc_bs_bshift < 32; 614 sc->sc_bs_bshift++) 615 if (FSS_FSBSIZE(sc) == fsbsize) 616 break; 617 if (sc->sc_bs_bshift >= 32) 618 return EINVAL; 619 sc->sc_bs_bmask = FSS_FSBSIZE(sc)-1; 620 sc->sc_flags |= FSS_BS_ALLOC; 621 } else { 622 sc->sc_bs_bshift = DEV_BSHIFT; 623 sc->sc_bs_bmask = FSS_FSBSIZE(sc)-1; 624 sc->sc_flags &= ~FSS_BS_ALLOC; 625 } 626 627 /* 628 * As all IO to from/to the backing store goes through 629 * VOP_STRATEGY() clean the buffer cache to prevent 630 * cache incoherencies. 631 */ 632 if ((error = vinvalbuf(sc->sc_bs_vp, V_SAVE, p->p_ucred, p, 0, 0)) != 0) 633 return error; 634 635 return 0; 636 } 637 638 /* 639 * Create a snapshot. 640 */ 641 static int 642 fss_create_snapshot(struct fss_softc *sc, struct fss_set *fss, struct proc *p) 643 { 644 int len, error; 645 u_int32_t csize; 646 off_t bsize; 647 648 /* 649 * Open needed files. 650 */ 651 if ((error = fss_create_files(sc, fss, &bsize, p)) != 0) 652 goto bad; 653 654 if (sc->sc_flags & FSS_PERSISTENT) { 655 fss_softc_alloc(sc); 656 sc->sc_flags |= FSS_ACTIVE; 657 return 0; 658 } 659 660 /* 661 * Set cluster size. Must be a power of two and 662 * a multiple of backing store block size. 663 */ 664 if (fss->fss_csize <= 0) 665 csize = MAXPHYS; 666 else 667 csize = fss->fss_csize; 668 if (bsize/csize > FSS_CLUSTER_MAX) 669 csize = bsize/FSS_CLUSTER_MAX+1; 670 671 for (sc->sc_clshift = sc->sc_bs_bshift; sc->sc_clshift < 32; 672 sc->sc_clshift++) 673 if (FSS_CLSIZE(sc) >= csize) 674 break; 675 if (sc->sc_clshift >= 32) { 676 error = EINVAL; 677 goto bad; 678 } 679 sc->sc_clmask = FSS_CLSIZE(sc)-1; 680 681 /* 682 * Set number of cache slots. 683 */ 684 if (FSS_CLSIZE(sc) <= 8192) 685 sc->sc_cache_size = 32; 686 else if (FSS_CLSIZE(sc) <= 65536) 687 sc->sc_cache_size = 8; 688 else 689 sc->sc_cache_size = 4; 690 691 /* 692 * Set number of clusters and size of last cluster. 693 */ 694 sc->sc_clcount = FSS_BTOCL(sc, bsize-1)+1; 695 sc->sc_clresid = FSS_CLOFF(sc, bsize-1)+1; 696 697 /* 698 * Set size of indirect table. 699 */ 700 len = sc->sc_clcount*sizeof(u_int32_t); 701 sc->sc_indir_size = FSS_BTOCL(sc, len)+1; 702 sc->sc_clnext = sc->sc_indir_size; 703 sc->sc_indir_cur = 0; 704 705 if ((error = fss_softc_alloc(sc)) != 0) 706 goto bad; 707 708 /* 709 * Activate the snapshot. 710 */ 711 712 if ((error = vfs_write_suspend(sc->sc_mount, PUSER|PCATCH, 0)) != 0) 713 goto bad; 714 715 microtime(&sc->sc_time); 716 717 if (error == 0) 718 error = vn_cow_establish(sc->sc_mount_vp, 719 fss_copy_on_write, sc); 720 if (error == 0) 721 sc->sc_flags |= FSS_ACTIVE; 722 723 vfs_write_resume(sc->sc_mount); 724 725 if (error != 0) 726 goto bad; 727 728 #ifdef DEBUG 729 printf("fss%d: %s snapshot active\n", sc->sc_unit, sc->sc_mntname); 730 printf("fss%d: %u clusters of %u, %u cache slots, %u indir clusters\n", 731 sc->sc_unit, sc->sc_clcount, FSS_CLSIZE(sc), 732 sc->sc_cache_size, sc->sc_indir_size); 733 #endif 734 735 return 0; 736 737 bad: 738 fss_softc_free(sc); 739 if (sc->sc_bs_vp != NULL) { 740 if (sc->sc_flags & FSS_PERSISTENT) 741 vn_close(sc->sc_bs_vp, FREAD, p->p_ucred, p); 742 else 743 vn_close(sc->sc_bs_vp, FREAD|FWRITE, p->p_ucred, p); 744 } 745 sc->sc_bs_vp = NULL; 746 747 return error; 748 } 749 750 /* 751 * Delete a snapshot. 752 */ 753 static int 754 fss_delete_snapshot(struct fss_softc *sc, struct proc *p) 755 { 756 int s; 757 758 if ((sc->sc_flags & FSS_PERSISTENT) == 0) 759 vn_cow_disestablish(sc->sc_mount_vp, fss_copy_on_write, sc); 760 761 FSS_LOCK(sc, s); 762 sc->sc_flags &= ~(FSS_ACTIVE|FSS_ERROR); 763 sc->sc_mount = NULL; 764 sc->sc_bdev = NODEV; 765 FSS_UNLOCK(sc, s); 766 767 fss_softc_free(sc); 768 if (sc->sc_flags & FSS_PERSISTENT) 769 vn_close(sc->sc_bs_vp, FREAD, p->p_ucred, p); 770 else 771 vn_close(sc->sc_bs_vp, FREAD|FWRITE, p->p_ucred, p); 772 sc->sc_bs_vp = NULL; 773 sc->sc_flags &= ~FSS_PERSISTENT; 774 775 FSS_STAT_CLEAR(sc); 776 777 return 0; 778 } 779 780 /* 781 * Get the block address and number of contiguous blocks. 782 * If the file contains a hole, try to allocate. 783 * Backing store is locked by caller. 784 */ 785 static int 786 fss_bmap(struct fss_softc *sc, off_t start, int len, 787 struct vnode **vpp, daddr_t *bnp, int *runp) 788 { 789 int l, s, error; 790 struct buf *bp, **bpp; 791 792 if ((sc->sc_bs_vp->v_mount->mnt_flag & MNT_SOFTDEP) != 0) 793 bpp = &bp; 794 else 795 bpp = NULL; 796 797 error = VOP_BMAP(sc->sc_bs_vp, FSS_BTOFSB(sc, start), vpp, bnp, runp); 798 if ((error == 0 && *bnp != (daddr_t)-1) || 799 (sc->sc_flags & FSS_BS_ALLOC) == 0) 800 goto out; 801 802 if (start+len >= sc->sc_bs_size) { 803 error = ENOSPC; 804 goto out; 805 } 806 807 for (l = 0; l < len; l += FSS_FSBSIZE(sc)) { 808 error = VOP_BALLOC(sc->sc_bs_vp, start+l, FSS_FSBSIZE(sc), 809 sc->sc_bs_proc->p_ucred, 0, bpp); 810 if (error) 811 goto out; 812 813 if (bpp == NULL) 814 continue; 815 816 s = splbio(); 817 simple_lock(&bp->b_interlock); 818 819 if (LIST_FIRST(&bp->b_dep) != NULL && bioops.io_start) 820 (*bioops.io_start)(bp); 821 if (LIST_FIRST(&bp->b_dep) != NULL && bioops.io_complete) 822 (*bioops.io_complete)(bp); 823 824 bp->b_flags |= B_INVAL; 825 simple_unlock(&bp->b_interlock); 826 splx(s); 827 828 brelse(bp); 829 } 830 831 error = VOP_BMAP(sc->sc_bs_vp, FSS_BTOFSB(sc, start), vpp, bnp, runp); 832 833 out: 834 835 if ((sc->sc_flags & FSS_PERSISTENT) == 0 && 836 error == 0 && *bnp == (daddr_t)-1) 837 error = ENOSPC; 838 839 return error; 840 } 841 842 /* 843 * A read from the snapshotted block device has completed. 844 */ 845 static void 846 fss_cluster_iodone(struct buf *bp) 847 { 848 int s; 849 struct fss_cache *scp = bp->b_private; 850 851 FSS_LOCK(scp->fc_softc, s); 852 853 if (bp->b_flags & B_EINTR) 854 fss_error(scp->fc_softc, "fs read interrupted"); 855 if (bp->b_flags & B_ERROR) 856 fss_error(scp->fc_softc, "fs read error %d", bp->b_error); 857 858 if (bp->b_vp != NULL) 859 brelvp(bp); 860 861 if (--scp->fc_xfercount == 0) 862 wakeup(&scp->fc_data); 863 864 FSS_UNLOCK(scp->fc_softc, s); 865 866 s = splbio(); 867 pool_put(&bufpool, bp); 868 splx(s); 869 } 870 871 /* 872 * Read a cluster from the snapshotted block device to the cache. 873 */ 874 static void 875 fss_read_cluster(struct fss_softc *sc, u_int32_t cl) 876 { 877 int s, todo, len; 878 caddr_t addr; 879 daddr_t dblk; 880 struct buf *bp; 881 struct fss_cache *scp, *scl; 882 883 /* 884 * Get a free cache slot. 885 */ 886 scl = sc->sc_cache+sc->sc_cache_size; 887 888 FSS_LOCK(sc, s); 889 890 restart: 891 if (isset(sc->sc_copied, cl) || !FSS_ISVALID(sc)) { 892 FSS_UNLOCK(sc, s); 893 return; 894 } 895 896 for (scp = sc->sc_cache; scp < scl; scp++) 897 if (scp->fc_type != FSS_CACHE_FREE && 898 scp->fc_cluster == cl) { 899 ltsleep(&scp->fc_type, PRIBIO, "cowwait2", 0, 900 &sc->sc_slock); 901 goto restart; 902 } 903 904 for (scp = sc->sc_cache; scp < scl; scp++) 905 if (scp->fc_type == FSS_CACHE_FREE) { 906 scp->fc_type = FSS_CACHE_BUSY; 907 scp->fc_cluster = cl; 908 break; 909 } 910 if (scp >= scl) { 911 FSS_STAT_INC(sc, cow_cache_full); 912 ltsleep(&sc->sc_cache, PRIBIO, "cowwait3", 0, &sc->sc_slock); 913 goto restart; 914 } 915 916 FSS_UNLOCK(sc, s); 917 918 /* 919 * Start the read. 920 */ 921 FSS_STAT_INC(sc, cow_copied); 922 923 dblk = btodb(FSS_CLTOB(sc, cl)); 924 addr = scp->fc_data; 925 if (cl == sc->sc_clcount-1) { 926 todo = sc->sc_clresid; 927 memset(addr+todo, 0, FSS_CLSIZE(sc)-todo); 928 } else 929 todo = FSS_CLSIZE(sc); 930 while (todo > 0) { 931 len = todo; 932 if (len > MAXPHYS) 933 len = MAXPHYS; 934 935 s = splbio(); 936 bp = pool_get(&bufpool, PR_WAITOK); 937 splx(s); 938 939 BUF_INIT(bp); 940 bp->b_flags = B_READ|B_CALL; 941 bp->b_bcount = len; 942 bp->b_bufsize = bp->b_bcount; 943 bp->b_error = 0; 944 bp->b_data = addr; 945 bp->b_blkno = bp->b_rawblkno = dblk; 946 bp->b_proc = NULL; 947 bp->b_dev = sc->sc_bdev; 948 bp->b_vp = NULLVP; 949 bp->b_private = scp; 950 bp->b_iodone = fss_cluster_iodone; 951 952 DEV_STRATEGY(bp); 953 954 FSS_LOCK(sc, s); 955 scp->fc_xfercount++; 956 FSS_UNLOCK(sc, s); 957 958 dblk += btodb(len); 959 addr += len; 960 todo -= len; 961 } 962 963 /* 964 * Wait for all read requests to complete. 965 */ 966 FSS_LOCK(sc, s); 967 while (scp->fc_xfercount > 0) 968 ltsleep(&scp->fc_data, PRIBIO, "cowwait", 0, &sc->sc_slock); 969 970 scp->fc_type = FSS_CACHE_VALID; 971 setbit(sc->sc_copied, scp->fc_cluster); 972 FSS_UNLOCK(sc, s); 973 974 wakeup(&sc->sc_bs_proc); 975 } 976 977 /* 978 * Write a cluster from the cache to the backing store. 979 */ 980 static int 981 fss_write_cluster(struct fss_cache *scp, u_int32_t cl) 982 { 983 int s, error, todo, len, nra; 984 daddr_t nbn; 985 caddr_t addr; 986 off_t pos; 987 struct buf *bp; 988 struct vnode *vp; 989 struct fss_softc *sc; 990 991 error = 0; 992 sc = scp->fc_softc; 993 994 pos = FSS_CLTOB(sc, cl); 995 addr = scp->fc_data; 996 todo = FSS_CLSIZE(sc); 997 998 vn_lock(sc->sc_bs_vp, LK_EXCLUSIVE|LK_RETRY); 999 simple_lock(&sc->sc_bs_vp->v_interlock); 1000 error = VOP_PUTPAGES(sc->sc_bs_vp, trunc_page(pos), 1001 round_page(pos+todo), PGO_CLEANIT|PGO_SYNCIO|PGO_FREE); 1002 1003 while (error == 0 && todo > 0) { 1004 error = fss_bmap(sc, pos, todo, &vp, &nbn, &nra); 1005 if (error) 1006 break; 1007 1008 len = FSS_FSBTOB(sc, nra+1)-FSS_FSBOFF(sc, pos); 1009 if (len > todo) 1010 len = todo; 1011 1012 s = splbio(); 1013 bp = pool_get(&bufpool, PR_WAITOK); 1014 splx(s); 1015 1016 BUF_INIT(bp); 1017 bp->b_flags = B_CALL; 1018 bp->b_bcount = len; 1019 bp->b_bufsize = bp->b_bcount; 1020 bp->b_error = 0; 1021 bp->b_data = addr; 1022 bp->b_blkno = bp->b_rawblkno = nbn+btodb(FSS_FSBOFF(sc, pos)); 1023 bp->b_proc = NULL; 1024 bp->b_vp = NULLVP; 1025 bp->b_private = scp; 1026 bp->b_iodone = fss_cluster_iodone; 1027 bgetvp(vp, bp); 1028 bp->b_vp->v_numoutput++; 1029 1030 BIO_SETPRIO(bp, BPRIO_TIMECRITICAL); 1031 VOP_STRATEGY(vp, bp); 1032 1033 FSS_LOCK(sc, s); 1034 scp->fc_xfercount++; 1035 FSS_UNLOCK(sc, s); 1036 1037 pos += len; 1038 addr += len; 1039 todo -= len; 1040 } 1041 1042 /* 1043 * Wait for all write requests to complete. 1044 */ 1045 FSS_LOCK(sc, s); 1046 while (scp->fc_xfercount > 0) 1047 ltsleep(&scp->fc_data, PRIBIO, "bswwait", 0, &sc->sc_slock); 1048 FSS_UNLOCK(sc, s); 1049 1050 VOP_UNLOCK(sc->sc_bs_vp, 0); 1051 1052 return error; 1053 } 1054 1055 /* 1056 * Read/write clusters from/to backing store. 1057 * For persistent snapshots must be called with cl == 0. off is the 1058 * offset into the snapshot. 1059 */ 1060 static int 1061 fss_bs_io(struct fss_softc *sc, fss_io_type rw, 1062 u_int32_t cl, off_t off, int len, caddr_t data) 1063 { 1064 int s, error, todo, count, nra; 1065 off_t pos; 1066 daddr_t nbn; 1067 struct buf *bp; 1068 struct vnode *vp; 1069 1070 todo = len; 1071 pos = FSS_CLTOB(sc, cl)+off; 1072 error = 0; 1073 1074 vn_lock(sc->sc_bs_vp, LK_EXCLUSIVE|LK_RETRY); 1075 simple_lock(&sc->sc_bs_vp->v_interlock); 1076 error = VOP_PUTPAGES(sc->sc_bs_vp, trunc_page(pos), 1077 round_page(pos+todo), PGO_CLEANIT|PGO_SYNCIO|PGO_FREE); 1078 1079 while (error == 0 && todo > 0) { 1080 error = fss_bmap(sc, pos, todo, &vp, &nbn, &nra); 1081 if (error) 1082 break; 1083 1084 count = FSS_FSBTOB(sc, nra+1)-FSS_FSBOFF(sc, pos); 1085 if (count > todo) 1086 count = todo; 1087 1088 if (nbn == (daddr_t)-1) { 1089 bzero(data, count); 1090 todo -= count; 1091 data += count; 1092 pos += count; 1093 continue; 1094 } 1095 1096 s = splbio(); 1097 bp = pool_get(&bufpool, PR_WAITOK); 1098 splx(s); 1099 1100 BUF_INIT(bp); 1101 bp->b_flags = (rw == FSS_READ ? B_READ : 0); 1102 bp->b_bcount = count; 1103 bp->b_bufsize = bp->b_bcount; 1104 bp->b_error = 0; 1105 bp->b_data = data; 1106 bp->b_blkno = bp->b_rawblkno = nbn+btodb(FSS_FSBOFF(sc, pos)); 1107 bp->b_proc = NULL; 1108 bp->b_vp = NULLVP; 1109 bgetvp(vp, bp); 1110 if ((bp->b_flags & B_READ) == 0) 1111 bp->b_vp->v_numoutput++; 1112 1113 if ((bp->b_flags & B_READ) == 0 || cl < sc->sc_indir_size) 1114 BIO_SETPRIO(bp, BPRIO_TIMECRITICAL); 1115 VOP_STRATEGY(vp, bp); 1116 1117 error = biowait(bp); 1118 1119 if (bp->b_vp != NULL) 1120 brelvp(bp); 1121 1122 s = splbio(); 1123 pool_put(&bufpool, bp); 1124 splx(s); 1125 1126 if (error) 1127 break; 1128 1129 todo -= count; 1130 data += count; 1131 pos += count; 1132 } 1133 1134 VOP_UNLOCK(sc->sc_bs_vp, 0); 1135 1136 return error; 1137 } 1138 1139 /* 1140 * Get a pointer to the indirect slot for this cluster. 1141 */ 1142 static u_int32_t * 1143 fss_bs_indir(struct fss_softc *sc, u_int32_t cl) 1144 { 1145 u_int32_t icl; 1146 int ioff; 1147 1148 icl = cl/(FSS_CLSIZE(sc)/sizeof(u_int32_t)); 1149 ioff = cl%(FSS_CLSIZE(sc)/sizeof(u_int32_t)); 1150 1151 if (sc->sc_indir_cur == icl) 1152 return &sc->sc_indir_data[ioff]; 1153 1154 if (sc->sc_indir_dirty) { 1155 FSS_STAT_INC(sc, indir_write); 1156 if (fss_bs_io(sc, FSS_WRITE, sc->sc_indir_cur, 0, 1157 FSS_CLSIZE(sc), (caddr_t)sc->sc_indir_data) != 0) 1158 return NULL; 1159 setbit(sc->sc_indir_valid, sc->sc_indir_cur); 1160 } 1161 1162 sc->sc_indir_dirty = 0; 1163 sc->sc_indir_cur = icl; 1164 1165 if (isset(sc->sc_indir_valid, sc->sc_indir_cur)) { 1166 FSS_STAT_INC(sc, indir_read); 1167 if (fss_bs_io(sc, FSS_READ, sc->sc_indir_cur, 0, 1168 FSS_CLSIZE(sc), (caddr_t)sc->sc_indir_data) != 0) 1169 return NULL; 1170 } else 1171 memset(sc->sc_indir_data, 0, FSS_CLSIZE(sc)); 1172 1173 return &sc->sc_indir_data[ioff]; 1174 } 1175 1176 /* 1177 * The kernel thread (one for every active snapshot). 1178 * 1179 * After wakeup it cleans the cache and runs the I/O requests. 1180 */ 1181 static void 1182 fss_bs_thread(void *arg) 1183 { 1184 int error, len, nfreed, nio, s; 1185 long off; 1186 caddr_t addr; 1187 u_int32_t c, cl, ch, *indirp; 1188 struct buf *bp, *nbp; 1189 struct fss_softc *sc; 1190 struct fss_cache *scp, *scl; 1191 1192 sc = arg; 1193 1194 scl = sc->sc_cache+sc->sc_cache_size; 1195 1196 s = splbio(); 1197 nbp = pool_get(&bufpool, PR_WAITOK); 1198 splx(s); 1199 1200 nfreed = nio = 1; /* Dont sleep the first time */ 1201 1202 FSS_LOCK(sc, s); 1203 1204 for (;;) { 1205 if (nfreed == 0 && nio == 0) 1206 ltsleep(&sc->sc_bs_proc, PVM-1, "fssbs", 0, 1207 &sc->sc_slock); 1208 1209 if ((sc->sc_flags & FSS_BS_THREAD) == 0) { 1210 sc->sc_bs_proc = NULL; 1211 wakeup(&sc->sc_bs_proc); 1212 1213 FSS_UNLOCK(sc, s); 1214 1215 s = splbio(); 1216 pool_put(&bufpool, nbp); 1217 splx(s); 1218 #ifdef FSS_STATISTICS 1219 if ((sc->sc_flags & FSS_PERSISTENT) == 0) { 1220 printf("fss%d: cow called %" PRId64 " times," 1221 " copied %" PRId64 " clusters," 1222 " cache full %" PRId64 " times\n", 1223 sc->sc_unit, 1224 FSS_STAT_VAL(sc, cow_calls), 1225 FSS_STAT_VAL(sc, cow_copied), 1226 FSS_STAT_VAL(sc, cow_cache_full)); 1227 printf("fss%d: %" PRId64 " indir reads," 1228 " %" PRId64 " indir writes\n", 1229 sc->sc_unit, 1230 FSS_STAT_VAL(sc, indir_read), 1231 FSS_STAT_VAL(sc, indir_write)); 1232 } 1233 #endif /* FSS_STATISTICS */ 1234 kthread_exit(0); 1235 } 1236 1237 /* 1238 * Process I/O requests (persistent) 1239 */ 1240 1241 if (sc->sc_flags & FSS_PERSISTENT) { 1242 nfreed = nio = 0; 1243 1244 if ((bp = BUFQ_GET(&sc->sc_bufq)) == NULL) 1245 continue; 1246 1247 nio++; 1248 1249 if (FSS_ISVALID(sc)) { 1250 FSS_UNLOCK(sc, s); 1251 1252 error = fss_bs_io(sc, FSS_READ, 0, 1253 dbtob(bp->b_blkno), bp->b_bcount, 1254 bp->b_data); 1255 1256 FSS_LOCK(sc, s); 1257 } else 1258 error = ENXIO; 1259 1260 if (error) { 1261 bp->b_error = error; 1262 bp->b_flags |= B_ERROR; 1263 bp->b_resid = bp->b_bcount; 1264 } 1265 biodone(bp); 1266 1267 continue; 1268 } 1269 1270 /* 1271 * Clean the cache 1272 */ 1273 nfreed = 0; 1274 for (scp = sc->sc_cache; scp < scl; scp++) { 1275 if (scp->fc_type != FSS_CACHE_VALID) 1276 continue; 1277 1278 FSS_UNLOCK(sc, s); 1279 1280 indirp = fss_bs_indir(sc, scp->fc_cluster); 1281 if (indirp != NULL) { 1282 error = fss_write_cluster(scp, sc->sc_clnext); 1283 } else 1284 error = EIO; 1285 1286 FSS_LOCK(sc, s); 1287 1288 if (error == 0) { 1289 *indirp = sc->sc_clnext++; 1290 sc->sc_indir_dirty = 1; 1291 } else 1292 fss_error(sc, "write bs error %d", error); 1293 1294 scp->fc_type = FSS_CACHE_FREE; 1295 nfreed++; 1296 wakeup(&scp->fc_type); 1297 } 1298 1299 if (nfreed) 1300 wakeup(&sc->sc_cache); 1301 1302 /* 1303 * Process I/O requests 1304 */ 1305 nio = 0; 1306 1307 if ((bp = BUFQ_GET(&sc->sc_bufq)) == NULL) 1308 continue; 1309 1310 nio++; 1311 1312 if (!FSS_ISVALID(sc)) { 1313 bp->b_error = ENXIO; 1314 bp->b_flags |= B_ERROR; 1315 bp->b_resid = bp->b_bcount; 1316 biodone(bp); 1317 continue; 1318 } 1319 1320 /* 1321 * First read from the snapshotted block device. 1322 * XXX Split to only read those parts that have not 1323 * been saved to backing store? 1324 */ 1325 1326 FSS_UNLOCK(sc, s); 1327 1328 BUF_INIT(nbp); 1329 nbp->b_flags = B_READ; 1330 nbp->b_bcount = bp->b_bcount; 1331 nbp->b_bufsize = bp->b_bcount; 1332 nbp->b_error = 0; 1333 nbp->b_data = bp->b_data; 1334 nbp->b_blkno = nbp->b_rawblkno = bp->b_blkno; 1335 nbp->b_proc = bp->b_proc; 1336 nbp->b_dev = sc->sc_bdev; 1337 nbp->b_vp = NULLVP; 1338 1339 DEV_STRATEGY(nbp); 1340 1341 if (biowait(nbp) != 0) { 1342 bp->b_resid = bp->b_bcount; 1343 bp->b_error = nbp->b_error; 1344 bp->b_flags |= B_ERROR; 1345 biodone(bp); 1346 continue; 1347 } 1348 1349 cl = FSS_BTOCL(sc, dbtob(bp->b_blkno)); 1350 off = FSS_CLOFF(sc, dbtob(bp->b_blkno)); 1351 ch = FSS_BTOCL(sc, dbtob(bp->b_blkno)+bp->b_bcount-1); 1352 bp->b_resid = bp->b_bcount; 1353 addr = bp->b_data; 1354 1355 FSS_LOCK(sc, s); 1356 1357 /* 1358 * Replace those parts that have been saved to backing store. 1359 */ 1360 1361 for (c = cl; c <= ch; 1362 c++, off = 0, bp->b_resid -= len, addr += len) { 1363 len = FSS_CLSIZE(sc)-off; 1364 if (len > bp->b_resid) 1365 len = bp->b_resid; 1366 1367 if (isclr(sc->sc_copied, c)) 1368 continue; 1369 1370 FSS_UNLOCK(sc, s); 1371 1372 indirp = fss_bs_indir(sc, c); 1373 1374 FSS_LOCK(sc, s); 1375 1376 if (indirp == NULL || *indirp == 0) { 1377 /* 1378 * Not on backing store. Either in cache 1379 * or hole in the snapshotted block device. 1380 */ 1381 for (scp = sc->sc_cache; scp < scl; scp++) 1382 if (scp->fc_type == FSS_CACHE_VALID && 1383 scp->fc_cluster == c) 1384 break; 1385 if (scp < scl) 1386 memcpy(addr, scp->fc_data+off, len); 1387 else 1388 memset(addr, 0, len); 1389 continue; 1390 } 1391 /* 1392 * Read from backing store. 1393 */ 1394 1395 FSS_UNLOCK(sc, s); 1396 1397 if ((error = fss_bs_io(sc, FSS_READ, *indirp, 1398 off, len, addr)) != 0) { 1399 bp->b_resid = bp->b_bcount; 1400 bp->b_error = error; 1401 bp->b_flags |= B_ERROR; 1402 break; 1403 } 1404 1405 FSS_LOCK(sc, s); 1406 1407 } 1408 1409 biodone(bp); 1410 } 1411 } 1412
Indexes created Wed Nov 11 00:26:22 UTC 2026