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sys/dev/fss.c
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1 /* $NetBSD: fss.c,v 1.7 2004/02/24 15:12:51 wiz 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 1.7 2004/02/24 15:12:51 wiz 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 void 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, long, 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 if ((sc->sc_flags & FSS_ACTIVE) == FSS_ACTIVE) { 280 memcpy(fsg->fsg_mount, sc->sc_mntname, MNAMELEN); 281 fsg->fsg_csize = FSS_CLSIZE(sc); 282 fsg->fsg_time = sc->sc_time; 283 fsg->fsg_mount_size = sc->sc_clcount; 284 fsg->fsg_bs_size = sc->sc_clnext; 285 error = 0; 286 } else 287 error = ENXIO; 288 break; 289 } 290 291 FSS_LOCK(sc, s); 292 sc->sc_flags &= ~FSS_EXCL; 293 FSS_UNLOCK(sc, s); 294 wakeup(sc); 295 296 return error; 297 } 298 299 int 300 fss_size(dev_t dev) 301 { 302 return -1; 303 } 304 305 int 306 fss_dump(dev_t dev, daddr_t blkno, caddr_t va, size_t size) 307 { 308 return EROFS; 309 } 310 311 /* 312 * An error occurred reading or writing the snapshot or backing store. 313 * If it is the first error log to console. 314 * The caller holds the simplelock. 315 */ 316 static inline void 317 fss_error(struct fss_softc *sc, const char *fmt, ...) 318 { 319 va_list ap; 320 321 if ((sc->sc_flags & (FSS_ACTIVE|FSS_ERROR)) == FSS_ACTIVE) { 322 va_start(ap, fmt); 323 printf("fss%d: snapshot invalid: ", sc->sc_unit); 324 vprintf(fmt, ap); 325 printf("\n"); 326 va_end(ap); 327 } 328 if ((sc->sc_flags & FSS_ACTIVE) == FSS_ACTIVE) 329 sc->sc_flags |= FSS_ERROR; 330 } 331 332 /* 333 * Allocate the variable sized parts of the softc and 334 * fork the kernel thread. 335 * 336 * The fields sc_clcount, sc_clshift, sc_cache_size and sc_indir_size 337 * must be initialized. 338 */ 339 static int 340 fss_softc_alloc(struct fss_softc *sc) 341 { 342 int i, len, error; 343 344 len = (sc->sc_clcount+NBBY-1)/NBBY; 345 sc->sc_copied = malloc(len, M_TEMP, M_ZERO|M_WAITOK|M_CANFAIL); 346 if (sc->sc_copied == NULL) 347 return(ENOMEM); 348 349 len = sc->sc_cache_size*sizeof(struct fss_cache); 350 sc->sc_cache = malloc(len, M_TEMP, M_ZERO|M_WAITOK|M_CANFAIL); 351 if (sc->sc_cache == NULL) 352 return(ENOMEM); 353 354 len = FSS_CLSIZE(sc); 355 for (i = 0; i < sc->sc_cache_size; i++) { 356 sc->sc_cache[i].fc_type = FSS_CACHE_FREE; 357 sc->sc_cache[i].fc_softc = sc; 358 sc->sc_cache[i].fc_xfercount = 0; 359 sc->sc_cache[i].fc_data = malloc(len, M_TEMP, 360 M_WAITOK|M_CANFAIL); 361 if (sc->sc_cache[i].fc_data == NULL) 362 return(ENOMEM); 363 } 364 365 len = (sc->sc_indir_size+NBBY-1)/NBBY; 366 sc->sc_indir_valid = malloc(len, M_TEMP, M_ZERO|M_WAITOK|M_CANFAIL); 367 if (sc->sc_indir_valid == NULL) 368 return(ENOMEM); 369 370 len = FSS_CLSIZE(sc); 371 sc->sc_indir_data = malloc(len, M_TEMP, M_ZERO|M_WAITOK|M_CANFAIL); 372 if (sc->sc_indir_data == NULL) 373 return(ENOMEM); 374 375 if ((error = kthread_create1(fss_bs_thread, sc, &sc->sc_bs_proc, 376 "fssbs%d", sc->sc_unit)) != 0) 377 return error; 378 379 sc->sc_flags |= FSS_BS_THREAD; 380 return 0; 381 } 382 383 /* 384 * Free the variable sized parts of the softc. 385 */ 386 static void 387 fss_softc_free(struct fss_softc *sc) 388 { 389 int s, i; 390 391 if ((sc->sc_flags & FSS_BS_THREAD) != 0) { 392 FSS_LOCK(sc, s); 393 sc->sc_flags &= ~FSS_BS_THREAD; 394 wakeup(&sc->sc_bs_proc); 395 while (sc->sc_bs_proc != NULL) 396 ltsleep(&sc->sc_bs_proc, PRIBIO, "fssthread", 0, 397 &sc->sc_slock); 398 FSS_UNLOCK(sc, s); 399 } 400 401 if (sc->sc_copied != NULL) 402 free(sc->sc_copied, M_TEMP); 403 sc->sc_copied = NULL; 404 405 if (sc->sc_cache != NULL) { 406 for (i = 0; i < sc->sc_cache_size; i++) 407 if (sc->sc_cache[i].fc_data != NULL) 408 free(sc->sc_cache[i].fc_data, M_TEMP); 409 free(sc->sc_cache, M_TEMP); 410 } 411 sc->sc_cache = NULL; 412 413 if (sc->sc_indir_valid != NULL) 414 free(sc->sc_indir_valid, M_TEMP); 415 sc->sc_indir_valid = NULL; 416 417 if (sc->sc_indir_data != NULL) 418 free(sc->sc_indir_data, M_TEMP); 419 sc->sc_indir_data = NULL; 420 } 421 422 /* 423 * Check if an unmount is ok. If forced, set this snapshot into ERROR state. 424 */ 425 int 426 fss_umount_hook(struct mount *mp, int forced) 427 { 428 int i, s; 429 430 for (i = 0; i < NFSS; i++) { 431 FSS_LOCK(&fss_softc[i], s); 432 if ((fss_softc[i].sc_flags & FSS_ACTIVE) != 0 && 433 fss_softc[i].sc_mount == mp) { 434 if (forced) 435 fss_error(&fss_softc[i], "forced unmount"); 436 else { 437 FSS_UNLOCK(&fss_softc[i], s); 438 return EBUSY; 439 } 440 } 441 FSS_UNLOCK(&fss_softc[i], s); 442 } 443 444 return 0; 445 } 446 447 /* 448 * A buffer is written to the snapshotted block device. Copy to 449 * backing store if needed. 450 */ 451 static void 452 fss_copy_on_write(void *v, struct buf *bp) 453 { 454 int s; 455 u_int32_t cl, ch, c; 456 struct fss_softc *sc = v; 457 458 FSS_LOCK(sc, s); 459 if (!FSS_ISVALID(sc)) { 460 FSS_UNLOCK(sc, s); 461 return; 462 } 463 464 FSS_UNLOCK(sc, s); 465 466 FSS_STAT_INC(sc, cow_calls); 467 468 cl = FSS_BTOCL(sc, dbtob(bp->b_blkno)); 469 ch = FSS_BTOCL(sc, dbtob(bp->b_blkno)+bp->b_bcount-1); 470 471 for (c = cl; c <= ch; c++) 472 fss_read_cluster(sc, c); 473 } 474 475 /* 476 * Lookup and open needed files. 477 * 478 * Returns dev and size of the underlying block device. 479 * Initializes sc_mntname, sc_mount_vp, sc_bdev, sc_bs_vp and sc_mount 480 */ 481 static int 482 fss_create_files(struct fss_softc *sc, struct fss_set *fss, 483 off_t *bsize, struct proc *p) 484 { 485 int error, fsbsize; 486 struct partinfo dpart; 487 struct vattr va; 488 struct nameidata nd; 489 490 /* 491 * Get the mounted file system. 492 */ 493 494 NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, fss->fss_mount, p); 495 if ((error = namei(&nd)) != 0) 496 return error; 497 498 vrele(nd.ni_vp); 499 500 if ((nd.ni_vp->v_flag & VROOT) != VROOT) 501 return EINVAL; 502 503 sc->sc_mount = nd.ni_vp->v_mount; 504 505 /* 506 * Get the block device it is mounted on. 507 */ 508 509 memcpy(sc->sc_mntname, sc->sc_mount->mnt_stat.f_mntonname, MNAMELEN); 510 511 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, 512 sc->sc_mount->mnt_stat.f_mntfromname, p); 513 if ((error = namei(&nd)) != 0) 514 return error; 515 516 if (nd.ni_vp->v_type != VBLK) { 517 vrele(nd.ni_vp); 518 return EINVAL; 519 } 520 521 error = VOP_IOCTL(nd.ni_vp, DIOCGPART, &dpart, FREAD, p->p_ucred, p); 522 if (error) { 523 vrele(nd.ni_vp); 524 return error; 525 } 526 527 sc->sc_mount_vp = nd.ni_vp; 528 sc->sc_bdev = nd.ni_vp->v_rdev; 529 *bsize = (off_t)dpart.disklab->d_secsize*dpart.part->p_size; 530 vrele(nd.ni_vp); 531 532 /* 533 * Get the backing store 534 */ 535 536 NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, fss->fss_bstore, p); 537 if ((error = vn_open(&nd, FREAD|FWRITE, 0)) != 0) 538 return error; 539 VOP_UNLOCK(nd.ni_vp, 0); 540 541 sc->sc_bs_vp = nd.ni_vp; 542 543 if (nd.ni_vp->v_type != VREG && nd.ni_vp->v_type != VCHR) 544 return EINVAL; 545 546 if (sc->sc_bs_vp->v_type == VREG) { 547 error = VOP_GETATTR(sc->sc_bs_vp, &va, p->p_ucred, p); 548 if (error != 0) 549 return error; 550 sc->sc_bs_size = va.va_size; 551 fsbsize = sc->sc_bs_vp->v_mount->mnt_stat.f_iosize; 552 if (fsbsize & (fsbsize-1)) /* No power of two */ 553 return EINVAL; 554 for (sc->sc_bs_bshift = 1; sc->sc_bs_bshift < 32; 555 sc->sc_bs_bshift++) 556 if (FSS_FSBSIZE(sc) == fsbsize) 557 break; 558 if (sc->sc_bs_bshift >= 32) 559 return EINVAL; 560 sc->sc_bs_bmask = FSS_FSBSIZE(sc)-1; 561 sc->sc_flags |= FSS_BS_ALLOC; 562 } else { 563 sc->sc_bs_bshift = DEV_BSHIFT; 564 sc->sc_bs_bmask = FSS_FSBSIZE(sc)-1; 565 sc->sc_flags &= ~FSS_BS_ALLOC; 566 } 567 568 /* 569 * As all IO to from/to the backing store goes through 570 * VOP_STRATEGY() clean the buffer cache to prevent 571 * cache incoherencies. 572 */ 573 if ((error = vinvalbuf(sc->sc_bs_vp, V_SAVE, p->p_ucred, p, 0, 0)) != 0) 574 return error; 575 576 return 0; 577 } 578 579 /* 580 * Create a snapshot. 581 */ 582 static int 583 fss_create_snapshot(struct fss_softc *sc, struct fss_set *fss, struct proc *p) 584 { 585 int len, error; 586 u_int32_t csize; 587 off_t bsize; 588 589 /* 590 * Open needed files. 591 */ 592 if ((error = fss_create_files(sc, fss, &bsize, p)) != 0) 593 goto bad; 594 595 if (sc->sc_bs_vp->v_type == VREG && 596 sc->sc_bs_vp->v_mount == sc->sc_mount) { 597 /* XXX need persistent snapshot inside the file system: 598 * VFS_SNAPSHOT(sc->sc_mount, sc->sc_bs_vp); 599 * sc->sc_time = xtime(sc->sc_bs_vp); 600 * sc->sc_flags |= FSS_PERSISTENT; 601 * fss_softc_alloc(sc); 602 * sc->sc_flags |= FSS_ACTIVE; 603 */ 604 error = EDEADLK; 605 goto bad; 606 } 607 608 /* 609 * Set cluster size. Must be a power of two and 610 * a multiple of backing store block size. 611 */ 612 if (fss->fss_csize <= 0) 613 csize = MAXPHYS; 614 else 615 csize = fss->fss_csize; 616 if (bsize/csize > FSS_CLUSTER_MAX) 617 csize = bsize/FSS_CLUSTER_MAX+1; 618 619 for (sc->sc_clshift = sc->sc_bs_bshift; sc->sc_clshift < 32; 620 sc->sc_clshift++) 621 if (FSS_CLSIZE(sc) >= csize) 622 break; 623 if (sc->sc_clshift >= 32) { 624 error = EINVAL; 625 goto bad; 626 } 627 sc->sc_clmask = FSS_CLSIZE(sc)-1; 628 629 /* 630 * Set number of cache slots. 631 */ 632 if (FSS_CLSIZE(sc) <= 8192) 633 sc->sc_cache_size = 32; 634 else if (FSS_CLSIZE(sc) <= 65536) 635 sc->sc_cache_size = 8; 636 else 637 sc->sc_cache_size = 4; 638 639 /* 640 * Set number of clusters and size of last cluster. 641 */ 642 sc->sc_clcount = FSS_BTOCL(sc, bsize-1)+1; 643 sc->sc_clresid = FSS_CLOFF(sc, bsize-1)+1; 644 645 /* 646 * Set size of indirect table. 647 */ 648 len = sc->sc_clcount*sizeof(u_int32_t); 649 sc->sc_indir_size = FSS_BTOCL(sc, len)+1; 650 sc->sc_clnext = sc->sc_indir_size; 651 sc->sc_indir_cur = 0; 652 653 if ((error = fss_softc_alloc(sc)) != 0) 654 goto bad; 655 656 /* 657 * Activate the snapshot. 658 */ 659 660 if ((error = vfs_write_suspend(sc->sc_mount, PUSER|PCATCH, 0)) != 0) 661 goto bad; 662 663 microtime(&sc->sc_time); 664 665 if (error == 0) 666 error = vn_cow_establish(sc->sc_mount_vp, 667 fss_copy_on_write, sc); 668 if (error == 0) 669 sc->sc_flags |= FSS_ACTIVE; 670 671 vfs_write_resume(sc->sc_mount); 672 673 if (error != 0) 674 goto bad; 675 676 #ifdef DEBUG 677 printf("fss%d: %s snapshot active\n", sc->sc_unit, sc->sc_mntname); 678 printf("fss%d: %u clusters of %u, %u cache slots, %u indir clusters\n", 679 sc->sc_unit, sc->sc_clcount, FSS_CLSIZE(sc), 680 sc->sc_cache_size, sc->sc_indir_size); 681 #endif 682 683 return 0; 684 685 bad: 686 fss_softc_free(sc); 687 if (sc->sc_bs_vp != NULL) 688 vn_close(sc->sc_bs_vp, FREAD|FWRITE, p->p_ucred, p); 689 sc->sc_bs_vp = NULL; 690 691 return error; 692 } 693 694 /* 695 * Delete a snapshot. 696 */ 697 static int 698 fss_delete_snapshot(struct fss_softc *sc, struct proc *p) 699 { 700 int s; 701 702 vn_cow_disestablish(sc->sc_mount_vp, fss_copy_on_write, sc); 703 704 FSS_LOCK(sc, s); 705 sc->sc_flags &= ~(FSS_ACTIVE|FSS_ERROR); 706 sc->sc_mount = NULL; 707 sc->sc_bdev = NODEV; 708 FSS_UNLOCK(sc, s); 709 710 fss_softc_free(sc); 711 vn_close(sc->sc_bs_vp, FREAD|FWRITE, p->p_ucred, p); 712 sc->sc_bs_vp = NULL; 713 714 FSS_STAT_CLEAR(sc); 715 716 return 0; 717 } 718 719 /* 720 * Get the block address and number of contiguous blocks. 721 * If the file contains a hole, try to allocate. 722 */ 723 static int 724 fss_bmap(struct fss_softc *sc, off_t start, int len, 725 struct vnode **vpp, daddr_t *bnp, int *runp) 726 { 727 int l, s, error; 728 struct buf *bp, **bpp; 729 730 if ((sc->sc_bs_vp->v_mount->mnt_flag & MNT_SOFTDEP) != 0) 731 bpp = &bp; 732 else 733 bpp = NULL; 734 735 vn_lock(sc->sc_bs_vp, LK_EXCLUSIVE|LK_RETRY); 736 737 error = VOP_BMAP(sc->sc_bs_vp, FSS_BTOFSB(sc, start), vpp, bnp, runp); 738 if ((error == 0 && *bnp != (daddr_t)-1) || 739 (sc->sc_flags & FSS_BS_ALLOC) == 0) 740 goto out; 741 742 if (start+len >= sc->sc_bs_size) { 743 error = ENOSPC; 744 goto out; 745 } 746 747 for (l = 0; l < len; l += FSS_FSBSIZE(sc)) { 748 error = VOP_BALLOC(sc->sc_bs_vp, start+l, FSS_FSBSIZE(sc), 749 sc->sc_bs_proc->p_ucred, 0, bpp); 750 if (error) 751 goto out; 752 753 if (bpp == NULL) 754 continue; 755 756 s = splbio(); 757 simple_lock(&bp->b_interlock); 758 759 if (LIST_FIRST(&bp->b_dep) != NULL && bioops.io_start) 760 (*bioops.io_start)(bp); 761 if (LIST_FIRST(&bp->b_dep) != NULL && bioops.io_complete) 762 (*bioops.io_complete)(bp); 763 764 bp->b_flags |= B_INVAL; 765 simple_unlock(&bp->b_interlock); 766 splx(s); 767 768 brelse(bp); 769 } 770 771 error = VOP_BMAP(sc->sc_bs_vp, FSS_BTOFSB(sc, start), vpp, bnp, runp); 772 773 out: 774 775 VOP_UNLOCK(sc->sc_bs_vp, 0); 776 if (error == 0 && *bnp == (daddr_t)-1) 777 error = ENOSPC; 778 779 return error; 780 } 781 782 /* 783 * A read from the snapshotted block device has completed. 784 */ 785 static void 786 fss_cluster_iodone(struct buf *bp) 787 { 788 int s; 789 struct fss_cache *scp = bp->b_private; 790 791 FSS_LOCK(scp->fc_softc, s); 792 793 if (bp->b_flags & B_EINTR) 794 fss_error(scp->fc_softc, "fs read interrupted"); 795 if (bp->b_flags & B_ERROR) 796 fss_error(scp->fc_softc, "fs read error %d", bp->b_error); 797 798 if (bp->b_vp != NULL) 799 brelvp(bp); 800 801 if (--scp->fc_xfercount == 0) 802 wakeup(&scp->fc_data); 803 804 FSS_UNLOCK(scp->fc_softc, s); 805 806 s = splbio(); 807 pool_put(&bufpool, bp); 808 splx(s); 809 } 810 811 /* 812 * Read a cluster from the snapshotted block device to the cache. 813 */ 814 static void 815 fss_read_cluster(struct fss_softc *sc, u_int32_t cl) 816 { 817 int s, todo, len; 818 caddr_t addr; 819 daddr_t dblk; 820 struct buf *bp; 821 struct fss_cache *scp, *scl; 822 823 /* 824 * Get a free cache slot. 825 */ 826 scl = sc->sc_cache+sc->sc_cache_size; 827 828 FSS_LOCK(sc, s); 829 830 restart: 831 if (isset(sc->sc_copied, cl) || !FSS_ISVALID(sc)) { 832 FSS_UNLOCK(sc, s); 833 return; 834 } 835 836 for (scp = sc->sc_cache; scp < scl; scp++) 837 if (scp->fc_type != FSS_CACHE_FREE && 838 scp->fc_cluster == cl) { 839 ltsleep(&scp->fc_type, PRIBIO, "cowwait2", 0, 840 &sc->sc_slock); 841 goto restart; 842 } 843 844 for (scp = sc->sc_cache; scp < scl; scp++) 845 if (scp->fc_type == FSS_CACHE_FREE) { 846 scp->fc_type = FSS_CACHE_BUSY; 847 scp->fc_cluster = cl; 848 break; 849 } 850 if (scp >= scl) { 851 FSS_STAT_INC(sc, cow_cache_full); 852 ltsleep(&sc->sc_cache, PRIBIO, "cowwait3", 0, &sc->sc_slock); 853 goto restart; 854 } 855 856 FSS_UNLOCK(sc, s); 857 858 /* 859 * Start the read. 860 */ 861 FSS_STAT_INC(sc, cow_copied); 862 863 dblk = btodb(FSS_CLTOB(sc, cl)); 864 addr = scp->fc_data; 865 if (cl == sc->sc_clcount-1) { 866 todo = sc->sc_clresid; 867 memset(addr+todo, 0, FSS_CLSIZE(sc)-todo); 868 } else 869 todo = FSS_CLSIZE(sc); 870 while (todo > 0) { 871 len = todo; 872 if (len > MAXPHYS) 873 len = MAXPHYS; 874 875 s = splbio(); 876 bp = pool_get(&bufpool, PR_WAITOK); 877 splx(s); 878 879 BUF_INIT(bp); 880 bp->b_flags = B_READ|B_CALL; 881 bp->b_bcount = len; 882 bp->b_bufsize = bp->b_bcount; 883 bp->b_error = 0; 884 bp->b_data = addr; 885 bp->b_blkno = bp->b_rawblkno = dblk; 886 bp->b_proc = NULL; 887 bp->b_dev = sc->sc_bdev; 888 bp->b_vp = NULLVP; 889 bp->b_private = scp; 890 bp->b_iodone = fss_cluster_iodone; 891 892 DEV_STRATEGY(bp); 893 894 FSS_LOCK(sc, s); 895 scp->fc_xfercount++; 896 FSS_UNLOCK(sc, s); 897 898 dblk += btodb(len); 899 addr += len; 900 todo -= len; 901 } 902 903 /* 904 * Wait for all read requests to complete. 905 */ 906 FSS_LOCK(sc, s); 907 while (scp->fc_xfercount > 0) 908 ltsleep(&scp->fc_data, PRIBIO, "cowwait", 0, &sc->sc_slock); 909 910 scp->fc_type = FSS_CACHE_VALID; 911 setbit(sc->sc_copied, scp->fc_cluster); 912 FSS_UNLOCK(sc, s); 913 914 wakeup(&sc->sc_bs_proc); 915 } 916 917 /* 918 * Write a cluster from the cache to the backing store. 919 */ 920 static int 921 fss_write_cluster(struct fss_cache *scp, u_int32_t cl) 922 { 923 int s, error, todo, len, nra; 924 daddr_t nbn; 925 caddr_t addr; 926 off_t pos; 927 struct buf *bp; 928 struct vnode *vp; 929 struct fss_softc *sc; 930 931 error = 0; 932 sc = scp->fc_softc; 933 934 pos = FSS_CLTOB(sc, cl); 935 addr = scp->fc_data; 936 todo = FSS_CLSIZE(sc); 937 938 while (todo > 0) { 939 error = fss_bmap(sc, pos, todo, &vp, &nbn, &nra); 940 if (error) 941 break; 942 943 len = FSS_FSBTOB(sc, nra+1)-FSS_FSBOFF(sc, pos); 944 if (len > todo) 945 len = todo; 946 947 s = splbio(); 948 bp = pool_get(&bufpool, PR_WAITOK); 949 splx(s); 950 951 BUF_INIT(bp); 952 bp->b_flags = B_CALL; 953 bp->b_bcount = len; 954 bp->b_bufsize = bp->b_bcount; 955 bp->b_error = 0; 956 bp->b_data = addr; 957 bp->b_blkno = bp->b_rawblkno = nbn+btodb(FSS_FSBOFF(sc, pos)); 958 bp->b_proc = NULL; 959 bp->b_vp = NULLVP; 960 bp->b_private = scp; 961 bp->b_iodone = fss_cluster_iodone; 962 bgetvp(vp, bp); 963 bp->b_vp->v_numoutput++; 964 965 BIO_SETPRIO(bp, BPRIO_TIMECRITICAL); 966 VOP_STRATEGY(vp, bp); 967 968 FSS_LOCK(sc, s); 969 scp->fc_xfercount++; 970 FSS_UNLOCK(sc, s); 971 972 pos += len; 973 addr += len; 974 todo -= len; 975 } 976 977 /* 978 * Wait for all write requests to complete. 979 */ 980 FSS_LOCK(sc, s); 981 while (scp->fc_xfercount > 0) 982 ltsleep(&scp->fc_data, PRIBIO, "bswwait", 0, &sc->sc_slock); 983 FSS_UNLOCK(sc, s); 984 985 return error; 986 } 987 988 /* 989 * Read/write clusters from/to backing store. 990 */ 991 static int 992 fss_bs_io(struct fss_softc *sc, fss_io_type rw, 993 u_int32_t cl, long off, int len, caddr_t data) 994 { 995 int s, error, todo, count, nra; 996 off_t pos; 997 daddr_t nbn; 998 struct buf *bp; 999 struct vnode *vp; 1000 1001 todo = len; 1002 pos = FSS_CLTOB(sc, cl)+off; 1003 error = 0; 1004 1005 while (todo > 0) { 1006 error = fss_bmap(sc, pos, todo, &vp, &nbn, &nra); 1007 if (error) 1008 break; 1009 1010 count = FSS_FSBTOB(sc, nra+1)-FSS_FSBOFF(sc, pos); 1011 if (count > todo) 1012 count = todo; 1013 1014 s = splbio(); 1015 bp = pool_get(&bufpool, PR_WAITOK); 1016 splx(s); 1017 1018 BUF_INIT(bp); 1019 bp->b_flags = (rw == FSS_READ ? B_READ : 0); 1020 bp->b_bcount = count; 1021 bp->b_bufsize = bp->b_bcount; 1022 bp->b_error = 0; 1023 bp->b_data = data; 1024 bp->b_blkno = bp->b_rawblkno = nbn+btodb(FSS_FSBOFF(sc, pos)); 1025 bp->b_proc = NULL; 1026 bp->b_vp = NULLVP; 1027 bgetvp(vp, bp); 1028 if ((bp->b_flags & B_READ) == 0) 1029 bp->b_vp->v_numoutput++; 1030 1031 if ((bp->b_flags & B_READ) == 0 || cl < sc->sc_indir_size) 1032 BIO_SETPRIO(bp, BPRIO_TIMECRITICAL); 1033 VOP_STRATEGY(vp, bp); 1034 1035 error = biowait(bp); 1036 1037 if (bp->b_vp != NULL) 1038 brelvp(bp); 1039 1040 s = splbio(); 1041 pool_put(&bufpool, bp); 1042 splx(s); 1043 1044 if (error) 1045 break; 1046 1047 todo -= count; 1048 data += count; 1049 pos += count; 1050 } 1051 1052 return error; 1053 } 1054 1055 /* 1056 * Get a pointer to the indirect slot for this cluster. 1057 */ 1058 static u_int32_t * 1059 fss_bs_indir(struct fss_softc *sc, u_int32_t cl) 1060 { 1061 u_int32_t icl; 1062 int ioff; 1063 1064 icl = cl/(FSS_CLSIZE(sc)/sizeof(u_int32_t)); 1065 ioff = cl%(FSS_CLSIZE(sc)/sizeof(u_int32_t)); 1066 1067 if (sc->sc_indir_cur == icl) 1068 return &sc->sc_indir_data[ioff]; 1069 1070 if (sc->sc_indir_dirty) { 1071 FSS_STAT_INC(sc, indir_write); 1072 if (fss_bs_io(sc, FSS_WRITE, sc->sc_indir_cur, 0, 1073 FSS_CLSIZE(sc), (caddr_t)sc->sc_indir_data) != 0) 1074 return NULL; 1075 setbit(sc->sc_indir_valid, sc->sc_indir_cur); 1076 } 1077 1078 sc->sc_indir_dirty = 0; 1079 sc->sc_indir_cur = icl; 1080 1081 if (isset(sc->sc_indir_valid, sc->sc_indir_cur)) { 1082 FSS_STAT_INC(sc, indir_read); 1083 if (fss_bs_io(sc, FSS_READ, sc->sc_indir_cur, 0, 1084 FSS_CLSIZE(sc), (caddr_t)sc->sc_indir_data) != 0) 1085 return NULL; 1086 } else 1087 memset(sc->sc_indir_data, 0, FSS_CLSIZE(sc)); 1088 1089 return &sc->sc_indir_data[ioff]; 1090 } 1091 1092 /* 1093 * The kernel thread (one for every active snapshot). 1094 * 1095 * After wakeup it cleans the cache and runs the I/O requests. 1096 */ 1097 static void 1098 fss_bs_thread(void *arg) 1099 { 1100 int error, len, nfreed, nio, s; 1101 long off; 1102 caddr_t addr; 1103 u_int32_t c, cl, ch, *indirp; 1104 struct buf *bp, *nbp; 1105 struct fss_softc *sc; 1106 struct fss_cache *scp, *scl; 1107 1108 sc = arg; 1109 1110 scl = sc->sc_cache+sc->sc_cache_size; 1111 1112 s = splbio(); 1113 nbp = pool_get(&bufpool, PR_WAITOK); 1114 splx(s); 1115 1116 nfreed = nio = 1; /* Dont sleep the first time */ 1117 1118 FSS_LOCK(sc, s); 1119 1120 for (;;) { 1121 if (nfreed == 0 && nio == 0) 1122 ltsleep(&sc->sc_bs_proc, PVM-1, "fssbs", 0, 1123 &sc->sc_slock); 1124 1125 if ((sc->sc_flags & FSS_BS_THREAD) == 0) { 1126 sc->sc_bs_proc = NULL; 1127 wakeup(&sc->sc_bs_proc); 1128 1129 FSS_UNLOCK(sc, s); 1130 1131 s = splbio(); 1132 pool_put(&bufpool, nbp); 1133 splx(s); 1134 #ifdef FSS_STATISTICS 1135 printf("fss%d: cow called %" PRId64 " times," 1136 " copied %" PRId64 " clusters," 1137 " cache full %" PRId64 " times\n", 1138 sc->sc_unit, 1139 FSS_STAT_VAL(sc, cow_calls), 1140 FSS_STAT_VAL(sc, cow_copied), 1141 FSS_STAT_VAL(sc, cow_cache_full)); 1142 printf("fss%d: %" PRId64 " indir reads," 1143 " %" PRId64 " indir writes\n", 1144 sc->sc_unit, 1145 FSS_STAT_VAL(sc, indir_read), 1146 FSS_STAT_VAL(sc, indir_write)); 1147 #endif /* FSS_STATISTICS */ 1148 kthread_exit(0); 1149 } 1150 1151 /* 1152 * Clean the cache 1153 */ 1154 nfreed = 0; 1155 for (scp = sc->sc_cache; scp < scl; scp++) { 1156 if (scp->fc_type != FSS_CACHE_VALID) 1157 continue; 1158 1159 FSS_UNLOCK(sc, s); 1160 1161 indirp = fss_bs_indir(sc, scp->fc_cluster); 1162 if (indirp != NULL) { 1163 error = fss_write_cluster(scp, sc->sc_clnext); 1164 } else 1165 error = EIO; 1166 1167 FSS_LOCK(sc, s); 1168 1169 if (error == 0) { 1170 *indirp = sc->sc_clnext++; 1171 sc->sc_indir_dirty = 1; 1172 } else 1173 fss_error(sc, "write bs error %d", error); 1174 1175 scp->fc_type = FSS_CACHE_FREE; 1176 nfreed++; 1177 wakeup(&scp->fc_type); 1178 } 1179 1180 if (nfreed) 1181 wakeup(&sc->sc_cache); 1182 1183 /* 1184 * Process I/O requests 1185 */ 1186 nio = 0; 1187 1188 if ((bp = BUFQ_GET(&sc->sc_bufq)) == NULL) 1189 continue; 1190 1191 nio++; 1192 1193 if (!FSS_ISVALID(sc)) { 1194 bp->b_error = ENXIO; 1195 bp->b_flags |= B_ERROR; 1196 bp->b_resid = bp->b_bcount; 1197 biodone(bp); 1198 continue; 1199 } 1200 1201 /* 1202 * First read from the snapshotted block device. 1203 * XXX Split to only read those parts that have not 1204 * been saved to backing store? 1205 */ 1206 1207 FSS_UNLOCK(sc, s); 1208 1209 BUF_INIT(nbp); 1210 nbp->b_flags = B_READ; 1211 nbp->b_bcount = bp->b_bcount; 1212 nbp->b_bufsize = bp->b_bcount; 1213 nbp->b_error = 0; 1214 nbp->b_data = bp->b_data; 1215 nbp->b_blkno = nbp->b_rawblkno = bp->b_blkno; 1216 nbp->b_proc = bp->b_proc; 1217 nbp->b_dev = sc->sc_bdev; 1218 nbp->b_vp = NULLVP; 1219 1220 DEV_STRATEGY(nbp); 1221 1222 if (biowait(nbp) != 0) { 1223 bp->b_resid = bp->b_bcount; 1224 bp->b_error = nbp->b_error; 1225 bp->b_flags |= B_ERROR; 1226 biodone(bp); 1227 continue; 1228 } 1229 1230 cl = FSS_BTOCL(sc, dbtob(bp->b_blkno)); 1231 off = FSS_CLOFF(sc, dbtob(bp->b_blkno)); 1232 ch = FSS_BTOCL(sc, dbtob(bp->b_blkno)+bp->b_bcount-1); 1233 bp->b_resid = bp->b_bcount; 1234 addr = bp->b_data; 1235 1236 FSS_LOCK(sc, s); 1237 1238 /* 1239 * Replace those parts that have been saved to backing store. 1240 */ 1241 1242 for (c = cl; c <= ch; 1243 c++, off = 0, bp->b_resid -= len, addr += len) { 1244 len = FSS_CLSIZE(sc)-off; 1245 if (len > bp->b_resid) 1246 len = bp->b_resid; 1247 1248 if (isclr(sc->sc_copied, c)) 1249 continue; 1250 1251 FSS_UNLOCK(sc, s); 1252 1253 indirp = fss_bs_indir(sc, c); 1254 1255 FSS_LOCK(sc, s); 1256 1257 if (indirp == NULL || *indirp == 0) { 1258 /* 1259 * Not on backing store. Either in cache 1260 * or hole in the snapshotted block device. 1261 */ 1262 for (scp = sc->sc_cache; scp < scl; scp++) 1263 if (scp->fc_type == FSS_CACHE_VALID && 1264 scp->fc_cluster == c) 1265 break; 1266 if (scp < scl) 1267 memcpy(addr, scp->fc_data+off, len); 1268 else 1269 memset(addr, 0, len); 1270 continue; 1271 } 1272 /* 1273 * Read from backing store. 1274 */ 1275 1276 FSS_UNLOCK(sc, s); 1277 1278 if ((error = fss_bs_io(sc, FSS_READ, *indirp, 1279 off, len, addr)) != 0) { 1280 bp->b_resid = bp->b_bcount; 1281 bp->b_error = error; 1282 bp->b_flags |= B_ERROR; 1283 break; 1284 } 1285 1286 FSS_LOCK(sc, s); 1287 1288 } 1289 1290 biodone(bp); 1291 } 1292 }
Cache object: 53ed90a1dcc9d495e0b84479263c1dfa
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