ffs_snapshot.c revision 1.142
1/* $NetBSD: ffs_snapshot.c,v 1.142 2016/10/21 19:28:03 jdolecek Exp $ */ 2 3/* 4 * Copyright 2000 Marshall Kirk McKusick. All Rights Reserved. 5 * 6 * Further information about snapshots can be obtained from: 7 * 8 * Marshall Kirk McKusick http://www.mckusick.com/softdep/ 9 * 1614 Oxford Street mckusick@mckusick.com 10 * Berkeley, CA 94709-1608 +1-510-843-9542 11 * USA 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 23 * THIS SOFTWARE IS PROVIDED BY MARSHALL KIRK MCKUSICK ``AS IS'' AND ANY 24 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 25 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 26 * DISCLAIMED. IN NO EVENT SHALL MARSHALL KIRK MCKUSICK BE LIABLE FOR 27 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 * 35 * @(#)ffs_snapshot.c 8.11 (McKusick) 7/23/00 36 * 37 * from FreeBSD: ffs_snapshot.c,v 1.79 2004/02/13 02:02:06 kuriyama Exp 38 */ 39 40#include <sys/cdefs.h> 41__KERNEL_RCSID(0, "$NetBSD: ffs_snapshot.c,v 1.142 2016/10/21 19:28:03 jdolecek Exp $"); 42 43#if defined(_KERNEL_OPT) 44#include "opt_ffs.h" 45#include "opt_quota.h" 46#endif 47 48#include <sys/param.h> 49#include <sys/kernel.h> 50#include <sys/systm.h> 51#include <sys/conf.h> 52#include <sys/buf.h> 53#include <sys/proc.h> 54#include <sys/namei.h> 55#include <sys/sched.h> 56#include <sys/stat.h> 57#include <sys/malloc.h> 58#include <sys/mount.h> 59#include <sys/resource.h> 60#include <sys/resourcevar.h> 61#include <sys/vnode.h> 62#include <sys/kauth.h> 63#include <sys/fstrans.h> 64#include <sys/wapbl.h> 65 66#include <miscfs/specfs/specdev.h> 67 68#include <ufs/ufs/quota.h> 69#include <ufs/ufs/ufsmount.h> 70#include <ufs/ufs/inode.h> 71#include <ufs/ufs/ufs_extern.h> 72#include <ufs/ufs/ufs_bswap.h> 73#include <ufs/ufs/ufs_wapbl.h> 74 75#include <ufs/ffs/fs.h> 76#include <ufs/ffs/ffs_extern.h> 77 78#include <uvm/uvm.h> 79 80TAILQ_HEAD(inodelst, inode); /* List of active snapshots */ 81 82struct snap_info { 83 kmutex_t si_lock; /* Lock this snapinfo */ 84 kmutex_t si_snaplock; /* Snapshot vnode common lock */ 85 lwp_t *si_owner; /* Snaplock owner */ 86 struct inodelst si_snapshots; /* List of active snapshots */ 87 daddr_t *si_snapblklist; /* Snapshot block hints list */ 88 uint32_t si_gen; /* Incremented on change */ 89}; 90 91#if !defined(FFS_NO_SNAPSHOT) 92typedef int (*acctfunc_t) 93 (struct vnode *, void *, int, int, struct fs *, daddr_t, int); 94 95static int snapshot_setup(struct mount *, struct vnode *); 96static int snapshot_copyfs(struct mount *, struct vnode *, void **); 97static int snapshot_expunge(struct mount *, struct vnode *, 98 struct fs *, daddr_t *, daddr_t **); 99static int snapshot_expunge_snap(struct mount *, struct vnode *, 100 struct fs *, daddr_t); 101static int snapshot_writefs(struct mount *, struct vnode *, void *); 102static int cgaccount(struct vnode *, int, int *); 103static int cgaccount1(int, struct vnode *, void *, int); 104static int expunge(struct vnode *, struct inode *, struct fs *, 105 acctfunc_t, int); 106static int indiracct(struct vnode *, struct vnode *, int, daddr_t, 107 daddr_t, daddr_t, daddr_t, daddr_t, struct fs *, acctfunc_t, int); 108static int fullacct(struct vnode *, void *, int, int, struct fs *, 109 daddr_t, int); 110static int snapacct(struct vnode *, void *, int, int, struct fs *, 111 daddr_t, int); 112static int mapacct(struct vnode *, void *, int, int, struct fs *, 113 daddr_t, int); 114#endif /* !defined(FFS_NO_SNAPSHOT) */ 115 116static int ffs_copyonwrite(void *, struct buf *, bool); 117static int snapblkaddr(struct vnode *, daddr_t, daddr_t *); 118static int rwfsblk(struct vnode *, int, void *, daddr_t); 119static int syncsnap(struct vnode *); 120static int wrsnapblk(struct vnode *, void *, daddr_t); 121#if !defined(FFS_NO_SNAPSHOT) 122static int blocks_in_journal(struct fs *); 123#endif 124 125static inline bool is_active_snapshot(struct snap_info *, struct inode *); 126static inline daddr_t db_get(struct inode *, int); 127static inline void db_assign(struct inode *, int, daddr_t); 128static inline daddr_t ib_get(struct inode *, int); 129static inline daddr_t idb_get(struct inode *, void *, int); 130static inline void idb_assign(struct inode *, void *, int, daddr_t); 131 132#ifdef DEBUG 133static int snapdebug = 0; 134#endif 135 136int 137ffs_snapshot_init(struct ufsmount *ump) 138{ 139 struct snap_info *si; 140 141 si = ump->um_snapinfo = kmem_alloc(sizeof(*si), KM_SLEEP); 142 if (si == NULL) 143 return ENOMEM; 144 145 TAILQ_INIT(&si->si_snapshots); 146 mutex_init(&si->si_lock, MUTEX_DEFAULT, IPL_NONE); 147 mutex_init(&si->si_snaplock, MUTEX_DEFAULT, IPL_NONE); 148 si->si_owner = NULL; 149 si->si_gen = 0; 150 si->si_snapblklist = NULL; 151 152 return 0; 153} 154 155void 156ffs_snapshot_fini(struct ufsmount *ump) 157{ 158 struct snap_info *si; 159 160 si = ump->um_snapinfo; 161 ump->um_snapinfo = NULL; 162 163 KASSERT(TAILQ_EMPTY(&si->si_snapshots)); 164 mutex_destroy(&si->si_lock); 165 mutex_destroy(&si->si_snaplock); 166 KASSERT(si->si_snapblklist == NULL); 167 kmem_free(si, sizeof(*si)); 168} 169 170/* 171 * Create a snapshot file and initialize it for the filesystem. 172 * Vnode is locked on entry and return. 173 */ 174int 175ffs_snapshot(struct mount *mp, struct vnode *vp, struct timespec *ctime) 176{ 177#if defined(FFS_NO_SNAPSHOT) 178 return EOPNOTSUPP; 179} 180#else /* defined(FFS_NO_SNAPSHOT) */ 181 bool suspended = false; 182 int error, redo = 0, snaploc; 183 void *sbbuf = NULL; 184 daddr_t *snaplist = NULL, snaplistsize = 0; 185 struct buf *bp, *nbp; 186 struct fs *copy_fs = NULL; 187 struct fs *fs = VFSTOUFS(mp)->um_fs; 188 struct inode *ip = VTOI(vp); 189 struct lwp *l = curlwp; 190 struct snap_info *si = VFSTOUFS(mp)->um_snapinfo; 191 struct timespec ts; 192 struct timeval starttime; 193#ifdef DEBUG 194 struct timeval endtime; 195#endif 196 struct vnode *devvp = ip->i_devvp; 197 198 /* 199 * If the vnode already is a snapshot, return. 200 */ 201 if ((ip->i_flags & SF_SNAPSHOT)) { 202 if ((ip->i_flags & SF_SNAPINVAL)) 203 return EINVAL; 204 if (ctime) { 205 ctime->tv_sec = DIP(ip, mtime); 206 ctime->tv_nsec = DIP(ip, mtimensec); 207 } 208 return 0; 209 } 210 /* 211 * Check for free snapshot slot in the superblock. 212 */ 213 for (snaploc = 0; snaploc < FSMAXSNAP; snaploc++) 214 if (fs->fs_snapinum[snaploc] == 0) 215 break; 216 if (snaploc == FSMAXSNAP) 217 return (ENOSPC); 218 /* 219 * Prepare the vnode to become a snapshot. 220 */ 221 error = snapshot_setup(mp, vp); 222 if (error) 223 goto out; 224 225 /* 226 * Copy all the cylinder group maps. Although the 227 * filesystem is still active, we hope that only a few 228 * cylinder groups will change between now and when we 229 * suspend operations. Thus, we will be able to quickly 230 * touch up the few cylinder groups that changed during 231 * the suspension period. 232 */ 233 error = cgaccount(vp, 1, NULL); 234 if (error) 235 goto out; 236 237 /* 238 * snapshot is now valid 239 */ 240 ip->i_flags &= ~SF_SNAPINVAL; 241 DIP_ASSIGN(ip, flags, ip->i_flags); 242 ip->i_flag |= IN_CHANGE | IN_UPDATE; 243 244 /* 245 * Ensure that the snapshot is completely on disk. 246 * Since we have marked it as a snapshot it is safe to 247 * unlock it as no process will be allowed to write to it. 248 */ 249 error = VOP_FSYNC(vp, l->l_cred, FSYNC_WAIT, 0, 0); 250 if (error) 251 goto out; 252 VOP_UNLOCK(vp); 253 /* 254 * All allocations are done, so we can now suspend the filesystem. 255 */ 256 error = vfs_suspend(vp->v_mount, 0); 257 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 258 if (error) 259 goto out; 260 suspended = true; 261 getmicrotime(&starttime); 262 /* 263 * First, copy all the cylinder group maps that have changed. 264 */ 265 error = cgaccount(vp, 2, &redo); 266 if (error) 267 goto out; 268 /* 269 * Create a copy of the superblock and its summary information. 270 */ 271 error = snapshot_copyfs(mp, vp, &sbbuf); 272 if (error) 273 goto out; 274 copy_fs = (struct fs *)((char *)sbbuf + ffs_blkoff(fs, fs->fs_sblockloc)); 275 /* 276 * Expunge unlinked files from our view. 277 */ 278 error = snapshot_expunge(mp, vp, copy_fs, &snaplistsize, &snaplist); 279 if (error) 280 goto out; 281 /* 282 * Record snapshot inode. Since this is the newest snapshot, 283 * it must be placed at the end of the list. 284 */ 285 if (ip->i_nlink > 0) 286 fs->fs_snapinum[snaploc] = ip->i_number; 287 288 mutex_enter(&si->si_lock); 289 if (is_active_snapshot(si, ip)) 290 panic("ffs_snapshot: %"PRIu64" already on list", ip->i_number); 291 TAILQ_INSERT_TAIL(&si->si_snapshots, ip, i_nextsnap); 292 if (TAILQ_FIRST(&si->si_snapshots) == ip) { 293 /* 294 * If this is the first snapshot on this filesystem, put the 295 * preliminary list in place and establish the cow handler. 296 */ 297 si->si_snapblklist = snaplist; 298 fscow_establish(mp, ffs_copyonwrite, devvp); 299 } 300 si->si_gen++; 301 mutex_exit(&si->si_lock); 302 303 vp->v_vflag |= VV_SYSTEM; 304 /* 305 * Set the mtime to the time the snapshot has been taken. 306 */ 307 TIMEVAL_TO_TIMESPEC(&starttime, &ts); 308 if (ctime) 309 *ctime = ts; 310 DIP_ASSIGN(ip, mtime, ts.tv_sec); 311 DIP_ASSIGN(ip, mtimensec, ts.tv_nsec); 312 ip->i_flag |= IN_CHANGE | IN_UPDATE; 313 /* 314 * Copy allocation information from all snapshots and then 315 * expunge them from our view. 316 */ 317 error = snapshot_expunge_snap(mp, vp, copy_fs, snaplistsize); 318 if (error) 319 goto out; 320 /* 321 * Write the superblock and its summary information to the snapshot. 322 */ 323 error = snapshot_writefs(mp, vp, sbbuf); 324 if (error) 325 goto out; 326 /* 327 * We're nearly done, ensure that the snapshot is completely on disk. 328 */ 329 error = VOP_FSYNC(vp, l->l_cred, FSYNC_WAIT, 0, 0); 330 if (error) 331 goto out; 332 /* 333 * Invalidate and free all pages on the snapshot vnode. 334 * We will read and write through the buffercache. 335 */ 336 mutex_enter(vp->v_interlock); 337 error = VOP_PUTPAGES(vp, 0, 0, 338 PGO_ALLPAGES | PGO_CLEANIT | PGO_SYNCIO | PGO_FREE); 339 if (error) 340 goto out; 341 /* 342 * Invalidate short ( < fs_bsize ) buffers. We will always read 343 * full size buffers later. 344 */ 345 mutex_enter(&bufcache_lock); 346 KASSERT(LIST_FIRST(&vp->v_dirtyblkhd) == NULL); 347 for (bp = LIST_FIRST(&vp->v_cleanblkhd); bp; bp = nbp) { 348 nbp = LIST_NEXT(bp, b_vnbufs); 349 if (bp->b_bcount == fs->fs_bsize) 350 continue; 351 error = bbusy(bp, false, 0, NULL); 352 if (error != 0) { 353 if (error == EPASSTHROUGH) { 354 nbp = LIST_FIRST(&vp->v_cleanblkhd); 355 continue; 356 } 357 break; 358 } 359 brelsel(bp, BC_INVAL | BC_VFLUSH); 360 } 361 mutex_exit(&bufcache_lock); 362 363out: 364 if (sbbuf != NULL) { 365 free(copy_fs->fs_csp, M_UFSMNT); 366 free(sbbuf, M_UFSMNT); 367 } 368 if (fs->fs_active != NULL) { 369 free(fs->fs_active, M_DEVBUF); 370 fs->fs_active = NULL; 371 } 372 373 mutex_enter(&si->si_lock); 374 if (snaplist != NULL) { 375 if (si->si_snapblklist == snaplist) 376 si->si_snapblklist = NULL; 377 free(snaplist, M_UFSMNT); 378 } 379 if (error) { 380 fs->fs_snapinum[snaploc] = 0; 381 } else { 382 /* 383 * As this is the newest list, it is the most inclusive, so 384 * should replace the previous list. 385 */ 386 si->si_snapblklist = ip->i_snapblklist; 387 } 388 si->si_gen++; 389 mutex_exit(&si->si_lock); 390 391 if (suspended) { 392 VOP_UNLOCK(vp); 393 vfs_resume(vp->v_mount); 394 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 395#ifdef DEBUG 396 getmicrotime(&endtime); 397 timersub(&endtime, &starttime, &endtime); 398 printf("%s: suspended %lld.%03d sec, redo %d of %d\n", 399 mp->mnt_stat.f_mntonname, (long long)endtime.tv_sec, 400 endtime.tv_usec / 1000, redo, fs->fs_ncg); 401#endif 402 } 403 if (error) { 404 if (UFS_WAPBL_BEGIN(mp) == 0) { 405 (void) ffs_truncate(vp, (off_t)0, 0, NOCRED); 406 UFS_WAPBL_END(mp); 407 } 408 } else if (ip->i_nlink > 0) 409 vref(vp); 410 return (error); 411} 412 413/* 414 * Prepare vnode to become a snapshot. 415 */ 416static int 417snapshot_setup(struct mount *mp, struct vnode *vp) 418{ 419 int error, n, len, loc, cg; 420 daddr_t blkno, numblks; 421 struct buf *ibp, *nbp; 422 struct fs *fs = VFSTOUFS(mp)->um_fs; 423 struct lwp *l = curlwp; 424 const int wbreak = blocks_in_journal(fs)/8; 425 struct inode *ip = VTOI(vp); 426 427 /* 428 * Check mount, readonly reference and owner. 429 */ 430 if (vp->v_mount != mp) 431 return EXDEV; 432 if (vp->v_writecount != 0) 433 return EBUSY; 434 error = kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_FS_SNAPSHOT, 435 0, mp, vp, NULL); 436 if (error) 437 return EACCES; 438 439 if (vp->v_size != 0) { 440 error = ffs_truncate(vp, 0, 0, NOCRED); 441 if (error) 442 return error; 443 } 444 445 /* Change inode to snapshot type file. */ 446 error = UFS_WAPBL_BEGIN(mp); 447 if (error) 448 return error; 449#if defined(QUOTA) || defined(QUOTA2) 450 /* shapshot inodes are not accounted in quotas */ 451 chkiq(ip, -1, l->l_cred, 0); 452#endif 453 ip->i_flags |= (SF_SNAPSHOT | SF_SNAPINVAL); 454 DIP_ASSIGN(ip, flags, ip->i_flags); 455 ip->i_flag |= IN_CHANGE | IN_UPDATE; 456 ffs_update(vp, NULL, NULL, UPDATE_WAIT); 457 UFS_WAPBL_END(mp); 458 459 KASSERT(ip->i_flags & SF_SNAPSHOT); 460 /* 461 * Write an empty list of preallocated blocks to the end of 462 * the snapshot to set size to at least that of the filesystem. 463 */ 464 numblks = howmany(fs->fs_size, fs->fs_frag); 465 blkno = 1; 466 blkno = ufs_rw64(blkno, UFS_FSNEEDSWAP(fs)); 467 error = vn_rdwr(UIO_WRITE, vp, 468 (void *)&blkno, sizeof(blkno), ffs_lblktosize(fs, (off_t)numblks), 469 UIO_SYSSPACE, IO_NODELOCKED|IO_UNIT, l->l_cred, NULL, NULL); 470 if (error) 471 return error; 472 /* 473 * Preallocate critical data structures so that we can copy 474 * them in without further allocation after we suspend all 475 * operations on the filesystem. We would like to just release 476 * the allocated buffers without writing them since they will 477 * be filled in below once we are ready to go, but this upsets 478 * the soft update code, so we go ahead and write the new buffers. 479 * 480 * Allocate all indirect blocks and mark all of them as not 481 * needing to be copied. 482 */ 483 error = UFS_WAPBL_BEGIN(mp); 484 if (error) 485 return error; 486 for (blkno = UFS_NDADDR, n = 0; blkno < numblks; blkno += FFS_NINDIR(fs)) { 487 error = ffs_balloc(vp, ffs_lblktosize(fs, (off_t)blkno), 488 fs->fs_bsize, l->l_cred, B_METAONLY, &ibp); 489 if (error) 490 goto out; 491 brelse(ibp, 0); 492 if (wbreak > 0 && (++n % wbreak) == 0) { 493 UFS_WAPBL_END(mp); 494 error = UFS_WAPBL_BEGIN(mp); 495 if (error) 496 return error; 497 } 498 } 499 /* 500 * Allocate copies for the superblock and its summary information. 501 */ 502 error = ffs_balloc(vp, fs->fs_sblockloc, fs->fs_sbsize, l->l_cred, 503 0, &nbp); 504 if (error) 505 goto out; 506 bawrite(nbp); 507 blkno = ffs_fragstoblks(fs, fs->fs_csaddr); 508 len = howmany(fs->fs_cssize, fs->fs_bsize); 509 for (loc = 0; loc < len; loc++) { 510 error = ffs_balloc(vp, ffs_lblktosize(fs, (off_t)(blkno + loc)), 511 fs->fs_bsize, l->l_cred, 0, &nbp); 512 if (error) 513 goto out; 514 bawrite(nbp); 515 if (wbreak > 0 && (++n % wbreak) == 0) { 516 UFS_WAPBL_END(mp); 517 error = UFS_WAPBL_BEGIN(mp); 518 if (error) 519 return error; 520 } 521 } 522 /* 523 * Allocate all cylinder group blocks. 524 */ 525 for (cg = 0; cg < fs->fs_ncg; cg++) { 526 error = ffs_balloc(vp, ffs_lfragtosize(fs, cgtod(fs, cg)), 527 fs->fs_bsize, l->l_cred, 0, &nbp); 528 if (error) 529 goto out; 530 bawrite(nbp); 531 if (wbreak > 0 && (++n % wbreak) == 0) { 532 UFS_WAPBL_END(mp); 533 error = UFS_WAPBL_BEGIN(mp); 534 if (error) 535 return error; 536 } 537 } 538 539out: 540 UFS_WAPBL_END(mp); 541 return error; 542} 543 544/* 545 * Create a copy of the superblock and its summary information. 546 * It is up to the caller to free copyfs and copy_fs->fs_csp. 547 */ 548static int 549snapshot_copyfs(struct mount *mp, struct vnode *vp, void **sbbuf) 550{ 551 int error, i, len, loc, size; 552 void *space; 553 int32_t *lp; 554 struct buf *bp; 555 struct fs *copyfs, *fs = VFSTOUFS(mp)->um_fs; 556 struct vnode *devvp = VTOI(vp)->i_devvp; 557 558 /* 559 * Grab a copy of the superblock and its summary information. 560 * We delay writing it until the suspension is released below. 561 */ 562 *sbbuf = malloc(fs->fs_bsize, M_UFSMNT, M_WAITOK); 563 loc = ffs_blkoff(fs, fs->fs_sblockloc); 564 if (loc > 0) 565 memset(*sbbuf, 0, loc); 566 copyfs = (struct fs *)((char *)(*sbbuf) + loc); 567 memcpy(copyfs, fs, fs->fs_sbsize); 568 size = fs->fs_bsize < SBLOCKSIZE ? fs->fs_bsize : SBLOCKSIZE; 569 if (fs->fs_sbsize < size) 570 memset((char *)(*sbbuf) + loc + fs->fs_sbsize, 0, 571 size - fs->fs_sbsize); 572 size = ffs_blkroundup(fs, fs->fs_cssize); 573 if (fs->fs_contigsumsize > 0) 574 size += fs->fs_ncg * sizeof(int32_t); 575 space = malloc(size, M_UFSMNT, M_WAITOK); 576 copyfs->fs_csp = space; 577 memcpy(copyfs->fs_csp, fs->fs_csp, fs->fs_cssize); 578 space = (char *)space + fs->fs_cssize; 579 loc = howmany(fs->fs_cssize, fs->fs_fsize); 580 i = fs->fs_frag - loc % fs->fs_frag; 581 len = (i == fs->fs_frag) ? 0 : i * fs->fs_fsize; 582 if (len > 0) { 583 if ((error = bread(devvp, FFS_FSBTODB(fs, fs->fs_csaddr + loc), 584 len, 0, &bp)) != 0) { 585 free(copyfs->fs_csp, M_UFSMNT); 586 free(*sbbuf, M_UFSMNT); 587 *sbbuf = NULL; 588 return error; 589 } 590 memcpy(space, bp->b_data, (u_int)len); 591 space = (char *)space + len; 592 brelse(bp, BC_INVAL | BC_NOCACHE); 593 } 594 if (fs->fs_contigsumsize > 0) { 595 copyfs->fs_maxcluster = lp = space; 596 for (i = 0; i < fs->fs_ncg; i++) 597 *lp++ = fs->fs_contigsumsize; 598 } 599 if (mp->mnt_wapbl) 600 copyfs->fs_flags &= ~FS_DOWAPBL; 601 return 0; 602} 603 604struct snapshot_expunge_ctx { 605 struct vnode *logvp; 606 struct lwp *l; 607 struct vnode *vp; 608 struct fs *copy_fs; 609}; 610 611static bool 612snapshot_expunge_selector(void *cl, struct vnode *xvp) 613{ 614 struct vattr vat; 615 struct snapshot_expunge_ctx *c = cl; 616 struct inode *xp; 617 618 xp = VTOI(xvp); 619 if (xvp->v_type == VNON || VTOI(xvp) == NULL || 620 (xp->i_flags & SF_SNAPSHOT)) 621 return false; 622#ifdef DEBUG 623 if (snapdebug) 624 vprint("ffs_snapshot: busy vnode", xvp); 625#endif 626 627 if (xvp == c->logvp) 628 return true; 629 630 if (VOP_GETATTR(xvp, &vat, c->l->l_cred) == 0 && 631 vat.va_nlink > 0) 632 return false; 633 634 if (ffs_checkfreefile(c->copy_fs, c->vp, xp->i_number)) 635 return false; 636 637 return true; 638} 639 640/* 641 * We must check for active files that have been unlinked (e.g., with a zero 642 * link count). We have to expunge all trace of these files from the snapshot 643 * so that they are not reclaimed prematurely by fsck or unnecessarily dumped. 644 * Note that we skip unlinked snapshot files as they will be handled separately. 645 * Calculate the snapshot list size and create a preliminary list. 646 */ 647static int 648snapshot_expunge(struct mount *mp, struct vnode *vp, struct fs *copy_fs, 649 daddr_t *snaplistsize, daddr_t **snaplist) 650{ 651 int cg, error = 0, len, loc; 652 daddr_t blkno, *blkp; 653 struct fs *fs = VFSTOUFS(mp)->um_fs; 654 struct inode *xp; 655 struct lwp *l = curlwp; 656 struct vnode *logvp = NULL, *xvp; 657 struct vnode_iterator *marker; 658 struct snapshot_expunge_ctx ctx; 659 660 *snaplist = NULL; 661 /* 662 * Get the log inode if any. 663 */ 664 if ((fs->fs_flags & FS_DOWAPBL) && 665 fs->fs_journal_location == UFS_WAPBL_JOURNALLOC_IN_FILESYSTEM) { 666 error = VFS_VGET(mp, 667 fs->fs_journallocs[UFS_WAPBL_INFS_INO], &logvp); 668 if (error) 669 goto out; 670 } 671 /* 672 * We also calculate the needed size for the snapshot list. 673 */ 674 *snaplistsize = fs->fs_ncg + howmany(fs->fs_cssize, fs->fs_bsize) + 675 FSMAXSNAP + 1 /* superblock */ + 1 /* last block */ + 1 /* size */; 676 677 vfs_vnode_iterator_init(mp, &marker); 678 ctx.logvp = logvp; 679 ctx.l = l; 680 ctx.vp = vp; 681 ctx.copy_fs = copy_fs; 682 while ((xvp = vfs_vnode_iterator_next(marker, snapshot_expunge_selector, 683 &ctx))) 684 { 685 /* 686 * If there is a fragment, clear it here. 687 */ 688 xp = VTOI(xvp); 689 blkno = 0; 690 loc = howmany(xp->i_size, fs->fs_bsize) - 1; 691 if (loc < UFS_NDADDR) { 692 len = ffs_fragroundup(fs, ffs_blkoff(fs, xp->i_size)); 693 if (len > 0 && len < fs->fs_bsize) { 694 error = UFS_WAPBL_BEGIN(mp); 695 if (error) { 696 vrele(xvp); 697 vfs_vnode_iterator_destroy(marker); 698 goto out; 699 } 700 ffs_blkfree_snap(copy_fs, vp, db_get(xp, loc), 701 len, xp->i_number); 702 blkno = db_get(xp, loc); 703 db_assign(xp, loc, 0); 704 UFS_WAPBL_END(mp); 705 } 706 } 707 *snaplistsize += 1; 708 error = expunge(vp, xp, copy_fs, fullacct, BLK_NOCOPY); 709 if (blkno) 710 db_assign(xp, loc, blkno); 711 if (!error) { 712 error = UFS_WAPBL_BEGIN(mp); 713 if (!error) { 714 error = ffs_freefile_snap(copy_fs, vp, 715 xp->i_number, xp->i_mode); 716 UFS_WAPBL_END(mp); 717 } 718 } 719 vrele(xvp); 720 if (error) { 721 vfs_vnode_iterator_destroy(marker); 722 goto out; 723 } 724 } 725 vfs_vnode_iterator_destroy(marker); 726 727 /* 728 * Create a preliminary list of preallocated snapshot blocks. 729 */ 730 *snaplist = malloc(*snaplistsize * sizeof(daddr_t), M_UFSMNT, M_WAITOK); 731 blkp = &(*snaplist)[1]; 732 *blkp++ = ffs_lblkno(fs, fs->fs_sblockloc); 733 blkno = ffs_fragstoblks(fs, fs->fs_csaddr); 734 for (cg = 0; cg < fs->fs_ncg; cg++) { 735 if (ffs_fragstoblks(fs, cgtod(fs, cg)) > blkno) 736 break; 737 *blkp++ = ffs_fragstoblks(fs, cgtod(fs, cg)); 738 } 739 len = howmany(fs->fs_cssize, fs->fs_bsize); 740 for (loc = 0; loc < len; loc++) 741 *blkp++ = blkno + loc; 742 for (; cg < fs->fs_ncg; cg++) 743 *blkp++ = ffs_fragstoblks(fs, cgtod(fs, cg)); 744 (*snaplist)[0] = blkp - &(*snaplist)[0]; 745 746out: 747 if (logvp != NULL) 748 vput(logvp); 749 if (error && *snaplist != NULL) { 750 free(*snaplist, M_UFSMNT); 751 *snaplist = NULL; 752 } 753 754 return error; 755} 756 757/* 758 * Copy allocation information from all the snapshots in this snapshot and 759 * then expunge them from its view. Also, collect the list of allocated 760 * blocks in i_snapblklist. 761 */ 762static int 763snapshot_expunge_snap(struct mount *mp, struct vnode *vp, 764 struct fs *copy_fs, daddr_t snaplistsize) 765{ 766 int error = 0, i; 767 daddr_t numblks, *snaplist = NULL; 768 struct fs *fs = VFSTOUFS(mp)->um_fs; 769 struct inode *ip = VTOI(vp), *xp; 770 struct lwp *l = curlwp; 771 struct snap_info *si = VFSTOUFS(mp)->um_snapinfo; 772 773 TAILQ_FOREACH(xp, &si->si_snapshots, i_nextsnap) { 774 if (xp != ip) { 775 error = expunge(vp, xp, fs, snapacct, BLK_SNAP); 776 if (error) 777 break; 778 } 779 if (xp->i_nlink != 0) 780 continue; 781 error = UFS_WAPBL_BEGIN(mp); 782 if (error) 783 break; 784 error = ffs_freefile_snap(copy_fs, vp, xp->i_number, xp->i_mode); 785 UFS_WAPBL_END(mp); 786 if (error) 787 break; 788 } 789 if (error) 790 goto out; 791 /* 792 * Allocate space for the full list of preallocated snapshot blocks. 793 */ 794 snaplist = malloc(snaplistsize * sizeof(daddr_t), M_UFSMNT, M_WAITOK); 795 ip->i_snapblklist = &snaplist[1]; 796 /* 797 * Expunge the blocks used by the snapshots from the set of 798 * blocks marked as used in the snapshot bitmaps. Also, collect 799 * the list of allocated blocks in i_snapblklist. 800 */ 801 error = expunge(vp, ip, copy_fs, mapacct, BLK_SNAP); 802 if (error) 803 goto out; 804 if (snaplistsize < ip->i_snapblklist - snaplist) 805 panic("ffs_snapshot: list too small"); 806 snaplistsize = ip->i_snapblklist - snaplist; 807 snaplist[0] = snaplistsize; 808 ip->i_snapblklist = &snaplist[0]; 809 /* 810 * Write out the list of allocated blocks to the end of the snapshot. 811 */ 812 numblks = howmany(fs->fs_size, fs->fs_frag); 813 for (i = 0; i < snaplistsize; i++) 814 snaplist[i] = ufs_rw64(snaplist[i], UFS_FSNEEDSWAP(fs)); 815 error = vn_rdwr(UIO_WRITE, vp, (void *)snaplist, 816 snaplistsize * sizeof(daddr_t), ffs_lblktosize(fs, (off_t)numblks), 817 UIO_SYSSPACE, IO_NODELOCKED | IO_UNIT, l->l_cred, NULL, NULL); 818 for (i = 0; i < snaplistsize; i++) 819 snaplist[i] = ufs_rw64(snaplist[i], UFS_FSNEEDSWAP(fs)); 820out: 821 if (error && snaplist != NULL) { 822 free(snaplist, M_UFSMNT); 823 ip->i_snapblklist = NULL; 824 } 825 return error; 826} 827 828/* 829 * Write the superblock and its summary information to the snapshot. 830 * Make sure, the first UFS_NDADDR blocks get copied to the snapshot. 831 */ 832static int 833snapshot_writefs(struct mount *mp, struct vnode *vp, void *sbbuf) 834{ 835 int error, len, loc; 836 void *space; 837 daddr_t blkno; 838 struct buf *bp; 839 struct fs *copyfs, *fs = VFSTOUFS(mp)->um_fs; 840 struct inode *ip = VTOI(vp); 841 struct lwp *l = curlwp; 842 843 copyfs = (struct fs *)((char *)sbbuf + ffs_blkoff(fs, fs->fs_sblockloc)); 844 845 /* 846 * Write the superblock and its summary information 847 * to the snapshot. 848 */ 849 blkno = ffs_fragstoblks(fs, fs->fs_csaddr); 850 len = howmany(fs->fs_cssize, fs->fs_bsize); 851 space = copyfs->fs_csp; 852#ifdef FFS_EI 853 if (UFS_FSNEEDSWAP(fs)) { 854 ffs_sb_swap(copyfs, copyfs); 855 ffs_csum_swap(space, space, fs->fs_cssize); 856 } 857#endif 858 error = UFS_WAPBL_BEGIN(mp); 859 if (error) 860 return error; 861 for (loc = 0; loc < len; loc++) { 862 error = bread(vp, blkno + loc, fs->fs_bsize, 863 B_MODIFY, &bp); 864 if (error) { 865 break; 866 } 867 memcpy(bp->b_data, space, fs->fs_bsize); 868 space = (char *)space + fs->fs_bsize; 869 bawrite(bp); 870 } 871 if (error) 872 goto out; 873 error = bread(vp, ffs_lblkno(fs, fs->fs_sblockloc), 874 fs->fs_bsize, B_MODIFY, &bp); 875 if (error) { 876 goto out; 877 } else { 878 memcpy(bp->b_data, sbbuf, fs->fs_bsize); 879 bawrite(bp); 880 } 881 /* 882 * Copy the first UFS_NDADDR blocks to the snapshot so 883 * ffs_copyonwrite() and ffs_snapblkfree() will always work on 884 * indirect blocks. 885 */ 886 for (loc = 0; loc < UFS_NDADDR; loc++) { 887 if (db_get(ip, loc) != 0) 888 continue; 889 error = ffs_balloc(vp, ffs_lblktosize(fs, (off_t)loc), 890 fs->fs_bsize, l->l_cred, 0, &bp); 891 if (error) 892 break; 893 error = rwfsblk(vp, B_READ, bp->b_data, loc); 894 if (error) { 895 brelse(bp, 0); 896 break; 897 } 898 bawrite(bp); 899 } 900 901out: 902 UFS_WAPBL_END(mp); 903 return error; 904} 905 906/* 907 * Copy all cylinder group maps. 908 */ 909static int 910cgaccount(struct vnode *vp, int passno, int *redo) 911{ 912 int cg, error = 0; 913 struct buf *nbp; 914 struct fs *fs = VTOI(vp)->i_fs; 915 916 if (redo != NULL) 917 *redo = 0; 918 if (passno == 1) 919 fs->fs_active = malloc(howmany(fs->fs_ncg, NBBY), 920 M_DEVBUF, M_WAITOK | M_ZERO); 921 for (cg = 0; cg < fs->fs_ncg; cg++) { 922 if (passno == 2 && ACTIVECG_ISSET(fs, cg)) 923 continue; 924 925 if (redo != NULL) 926 *redo += 1; 927 error = UFS_WAPBL_BEGIN(vp->v_mount); 928 if (error) 929 return error; 930 error = ffs_balloc(vp, ffs_lfragtosize(fs, cgtod(fs, cg)), 931 fs->fs_bsize, curlwp->l_cred, 0, &nbp); 932 if (error) { 933 UFS_WAPBL_END(vp->v_mount); 934 break; 935 } 936 error = cgaccount1(cg, vp, nbp->b_data, passno); 937 bawrite(nbp); 938 UFS_WAPBL_END(vp->v_mount); 939 if (error) 940 break; 941 } 942 return error; 943} 944 945/* 946 * Copy a cylinder group map. All the unallocated blocks are marked 947 * BLK_NOCOPY so that the snapshot knows that it need not copy them 948 * if they are later written. If passno is one, then this is a first 949 * pass, so only setting needs to be done. If passno is 2, then this 950 * is a revision to a previous pass which must be undone as the 951 * replacement pass is done. 952 */ 953static int 954cgaccount1(int cg, struct vnode *vp, void *data, int passno) 955{ 956 struct buf *bp, *ibp; 957 struct inode *ip; 958 struct cg *cgp; 959 struct fs *fs; 960 struct lwp *l = curlwp; 961 daddr_t base, numblks; 962 int error, len, loc, ns __unused, indiroff; 963 964 ip = VTOI(vp); 965 fs = ip->i_fs; 966 ns = UFS_FSNEEDSWAP(fs); 967 error = bread(ip->i_devvp, FFS_FSBTODB(fs, cgtod(fs, cg)), 968 (int)fs->fs_cgsize, 0, &bp); 969 if (error) { 970 return (error); 971 } 972 cgp = (struct cg *)bp->b_data; 973 if (!cg_chkmagic(cgp, ns)) { 974 brelse(bp, 0); 975 return (EIO); 976 } 977 ACTIVECG_SET(fs, cg); 978 979 memcpy(data, bp->b_data, fs->fs_cgsize); 980 brelse(bp, 0); 981 if (fs->fs_cgsize < fs->fs_bsize) 982 memset((char *)data + fs->fs_cgsize, 0, 983 fs->fs_bsize - fs->fs_cgsize); 984 numblks = howmany(fs->fs_size, fs->fs_frag); 985 len = howmany(fs->fs_fpg, fs->fs_frag); 986 base = cg * fs->fs_fpg / fs->fs_frag; 987 if (base + len >= numblks) 988 len = numblks - base - 1; 989 loc = 0; 990 if (base < UFS_NDADDR) { 991 for ( ; loc < UFS_NDADDR; loc++) { 992 if (ffs_isblock(fs, cg_blksfree(cgp, ns), loc)) 993 db_assign(ip, loc, BLK_NOCOPY); 994 else if (db_get(ip, loc) == BLK_NOCOPY) { 995 if (passno == 2) 996 db_assign(ip, loc, 0); 997 else if (passno == 1) 998 panic("ffs_snapshot: lost direct block"); 999 } 1000 } 1001 } 1002 if ((error = ffs_balloc(vp, ffs_lblktosize(fs, (off_t)(base + loc)), 1003 fs->fs_bsize, l->l_cred, B_METAONLY, &ibp)) != 0) 1004 return (error); 1005 indiroff = (base + loc - UFS_NDADDR) % FFS_NINDIR(fs); 1006 for ( ; loc < len; loc++, indiroff++) { 1007 if (indiroff >= FFS_NINDIR(fs)) { 1008 bawrite(ibp); 1009 if ((error = ffs_balloc(vp, 1010 ffs_lblktosize(fs, (off_t)(base + loc)), 1011 fs->fs_bsize, l->l_cred, B_METAONLY, &ibp)) != 0) 1012 return (error); 1013 indiroff = 0; 1014 } 1015 if (ffs_isblock(fs, cg_blksfree(cgp, ns), loc)) 1016 idb_assign(ip, ibp->b_data, indiroff, BLK_NOCOPY); 1017 else if (idb_get(ip, ibp->b_data, indiroff) == BLK_NOCOPY) { 1018 if (passno == 2) 1019 idb_assign(ip, ibp->b_data, indiroff, 0); 1020 else if (passno == 1) 1021 panic("ffs_snapshot: lost indirect block"); 1022 } 1023 } 1024 bdwrite(ibp); 1025 return (0); 1026} 1027 1028/* 1029 * Before expunging a snapshot inode, note all the 1030 * blocks that it claims with BLK_SNAP so that fsck will 1031 * be able to account for those blocks properly and so 1032 * that this snapshot knows that it need not copy them 1033 * if the other snapshot holding them is freed. 1034 */ 1035static int 1036expunge(struct vnode *snapvp, struct inode *cancelip, struct fs *fs, 1037 acctfunc_t acctfunc, int expungetype) 1038{ 1039 int i, error, ns __unused; 1040 daddr_t lbn, rlbn; 1041 daddr_t len, blkno, numblks, blksperindir; 1042 struct ufs1_dinode *dip1; 1043 struct ufs2_dinode *dip2; 1044 struct lwp *l = curlwp; 1045 void *bap; 1046 struct buf *bp; 1047 struct mount *mp; 1048 1049 ns = UFS_FSNEEDSWAP(fs); 1050 mp = snapvp->v_mount; 1051 1052 error = UFS_WAPBL_BEGIN(mp); 1053 if (error) 1054 return error; 1055 /* 1056 * Prepare to expunge the inode. If its inode block has not 1057 * yet been copied, then allocate and fill the copy. 1058 */ 1059 lbn = ffs_fragstoblks(fs, ino_to_fsba(fs, cancelip->i_number)); 1060 error = snapblkaddr(snapvp, lbn, &blkno); 1061 if (error) 1062 return error; 1063 if (blkno != 0) { 1064 error = bread(snapvp, lbn, fs->fs_bsize, 1065 B_MODIFY, &bp); 1066 } else { 1067 error = ffs_balloc(snapvp, ffs_lblktosize(fs, (off_t)lbn), 1068 fs->fs_bsize, l->l_cred, 0, &bp); 1069 if (! error) 1070 error = rwfsblk(snapvp, B_READ, bp->b_data, lbn); 1071 } 1072 if (error) { 1073 UFS_WAPBL_END(mp); 1074 return error; 1075 } 1076 /* 1077 * Set a snapshot inode to be a zero length file, regular files 1078 * or unlinked snapshots to be completely unallocated. 1079 */ 1080 if (fs->fs_magic == FS_UFS1_MAGIC) { 1081 dip1 = (struct ufs1_dinode *)bp->b_data + 1082 ino_to_fsbo(fs, cancelip->i_number); 1083 if (cancelip->i_flags & SF_SNAPSHOT) { 1084 dip1->di_flags = 1085 ufs_rw32(ufs_rw32(dip1->di_flags, ns) | 1086 SF_SNAPINVAL, ns); 1087 } 1088 if (expungetype == BLK_NOCOPY || cancelip->i_nlink == 0) 1089 dip1->di_mode = 0; 1090 dip1->di_size = 0; 1091 dip1->di_blocks = 0; 1092 memset(&dip1->di_db[0], 0, (UFS_NDADDR + UFS_NIADDR) * sizeof(int32_t)); 1093 } else { 1094 dip2 = (struct ufs2_dinode *)bp->b_data + 1095 ino_to_fsbo(fs, cancelip->i_number); 1096 if (cancelip->i_flags & SF_SNAPSHOT) { 1097 dip2->di_flags = 1098 ufs_rw32(ufs_rw32(dip2->di_flags, ns) | 1099 SF_SNAPINVAL, ns); 1100 } 1101 if (expungetype == BLK_NOCOPY || cancelip->i_nlink == 0) 1102 dip2->di_mode = 0; 1103 dip2->di_size = 0; 1104 dip2->di_blocks = 0; 1105 memset(&dip2->di_db[0], 0, (UFS_NDADDR + UFS_NIADDR) * sizeof(int64_t)); 1106 } 1107 bdwrite(bp); 1108 UFS_WAPBL_END(mp); 1109 /* 1110 * Now go through and expunge all the blocks in the file 1111 * using the function requested. 1112 */ 1113 numblks = howmany(cancelip->i_size, fs->fs_bsize); 1114 if (fs->fs_magic == FS_UFS1_MAGIC) 1115 bap = &cancelip->i_ffs1_db[0]; 1116 else 1117 bap = &cancelip->i_ffs2_db[0]; 1118 error = (*acctfunc)(snapvp, bap, 0, UFS_NDADDR, fs, 0, expungetype); 1119 if (error) 1120 return (error); 1121 if (fs->fs_magic == FS_UFS1_MAGIC) 1122 bap = &cancelip->i_ffs1_ib[0]; 1123 else 1124 bap = &cancelip->i_ffs2_ib[0]; 1125 error = (*acctfunc)(snapvp, bap, 0, UFS_NIADDR, fs, -1, expungetype); 1126 if (error) 1127 return (error); 1128 blksperindir = 1; 1129 lbn = -UFS_NDADDR; 1130 len = numblks - UFS_NDADDR; 1131 rlbn = UFS_NDADDR; 1132 for (i = 0; len > 0 && i < UFS_NIADDR; i++) { 1133 error = indiracct(snapvp, ITOV(cancelip), i, 1134 ib_get(cancelip, i), lbn, rlbn, len, 1135 blksperindir, fs, acctfunc, expungetype); 1136 if (error) 1137 return (error); 1138 blksperindir *= FFS_NINDIR(fs); 1139 lbn -= blksperindir + 1; 1140 len -= blksperindir; 1141 rlbn += blksperindir; 1142 } 1143 return (0); 1144} 1145 1146/* 1147 * Descend an indirect block chain for vnode cancelvp accounting for all 1148 * its indirect blocks in snapvp. 1149 */ 1150static int 1151indiracct(struct vnode *snapvp, struct vnode *cancelvp, int level, 1152 daddr_t blkno, daddr_t lbn, daddr_t rlbn, daddr_t remblks, 1153 daddr_t blksperindir, struct fs *fs, acctfunc_t acctfunc, int expungetype) 1154{ 1155 int error, num, i; 1156 daddr_t subblksperindir; 1157 struct indir indirs[UFS_NIADDR + 2]; 1158 daddr_t last; 1159 void *bap; 1160 struct buf *bp; 1161 1162 if (blkno == 0) { 1163 if (expungetype == BLK_NOCOPY) 1164 return (0); 1165 panic("indiracct: missing indir"); 1166 } 1167 if ((error = ufs_getlbns(cancelvp, rlbn, indirs, &num)) != 0) 1168 return (error); 1169 if (lbn != indirs[num - 1 - level].in_lbn || num < 2) 1170 panic("indiracct: botched params"); 1171 /* 1172 * We have to expand bread here since it will deadlock looking 1173 * up the block number for any blocks that are not in the cache. 1174 */ 1175 error = ffs_getblk(cancelvp, lbn, FFS_FSBTODB(fs, blkno), fs->fs_bsize, 1176 false, &bp); 1177 if (error) 1178 return error; 1179 if ((bp->b_oflags & (BO_DONE | BO_DELWRI)) == 0 && (error = 1180 rwfsblk(bp->b_vp, B_READ, bp->b_data, ffs_fragstoblks(fs, blkno)))) { 1181 brelse(bp, 0); 1182 return (error); 1183 } 1184 /* 1185 * Account for the block pointers in this indirect block. 1186 */ 1187 last = howmany(remblks, blksperindir); 1188 if (last > FFS_NINDIR(fs)) 1189 last = FFS_NINDIR(fs); 1190 bap = malloc(fs->fs_bsize, M_DEVBUF, M_WAITOK | M_ZERO); 1191 memcpy((void *)bap, bp->b_data, fs->fs_bsize); 1192 brelse(bp, 0); 1193 error = (*acctfunc)(snapvp, bap, 0, last, 1194 fs, level == 0 ? rlbn : -1, expungetype); 1195 if (error || level == 0) 1196 goto out; 1197 /* 1198 * Account for the block pointers in each of the indirect blocks 1199 * in the levels below us. 1200 */ 1201 subblksperindir = blksperindir / FFS_NINDIR(fs); 1202 for (lbn++, level--, i = 0; i < last; i++) { 1203 error = indiracct(snapvp, cancelvp, level, 1204 idb_get(VTOI(snapvp), bap, i), lbn, rlbn, remblks, 1205 subblksperindir, fs, acctfunc, expungetype); 1206 if (error) 1207 goto out; 1208 rlbn += blksperindir; 1209 lbn -= blksperindir; 1210 remblks -= blksperindir; 1211 } 1212out: 1213 free(bap, M_DEVBUF); 1214 return (error); 1215} 1216 1217/* 1218 * Do both snap accounting and map accounting. 1219 */ 1220static int 1221fullacct(struct vnode *vp, void *bap, int oldblkp, int lastblkp, 1222 struct fs *fs, daddr_t lblkno, 1223 int exptype /* BLK_SNAP or BLK_NOCOPY */) 1224{ 1225 int error; 1226 1227 if ((error = snapacct(vp, bap, oldblkp, lastblkp, fs, lblkno, exptype))) 1228 return (error); 1229 return (mapacct(vp, bap, oldblkp, lastblkp, fs, lblkno, exptype)); 1230} 1231 1232/* 1233 * Identify a set of blocks allocated in a snapshot inode. 1234 */ 1235static int 1236snapacct(struct vnode *vp, void *bap, int oldblkp, int lastblkp, 1237 struct fs *fs, daddr_t lblkno, 1238 int expungetype /* BLK_SNAP or BLK_NOCOPY */) 1239{ 1240 struct inode *ip = VTOI(vp); 1241 struct lwp *l = curlwp; 1242 struct mount *mp = vp->v_mount; 1243 daddr_t blkno; 1244 daddr_t lbn; 1245 struct buf *ibp; 1246 int error, n; 1247 const int wbreak = blocks_in_journal(VFSTOUFS(mp)->um_fs)/8; 1248 1249 error = UFS_WAPBL_BEGIN(mp); 1250 if (error) 1251 return error; 1252 for ( n = 0; oldblkp < lastblkp; oldblkp++) { 1253 blkno = idb_get(ip, bap, oldblkp); 1254 if (blkno == 0 || blkno == BLK_NOCOPY || blkno == BLK_SNAP) 1255 continue; 1256 lbn = ffs_fragstoblks(fs, blkno); 1257 if (lbn < UFS_NDADDR) { 1258 blkno = db_get(ip, lbn); 1259 ip->i_flag |= IN_CHANGE | IN_UPDATE; 1260 } else { 1261 error = ffs_balloc(vp, ffs_lblktosize(fs, (off_t)lbn), 1262 fs->fs_bsize, l->l_cred, B_METAONLY, &ibp); 1263 if (error) 1264 break; 1265 blkno = idb_get(ip, ibp->b_data, 1266 (lbn - UFS_NDADDR) % FFS_NINDIR(fs)); 1267 } 1268 /* 1269 * If we are expunging a snapshot vnode and we 1270 * find a block marked BLK_NOCOPY, then it is 1271 * one that has been allocated to this snapshot after 1272 * we took our current snapshot and can be ignored. 1273 */ 1274 if (expungetype == BLK_SNAP && blkno == BLK_NOCOPY) { 1275 if (lbn >= UFS_NDADDR) 1276 brelse(ibp, 0); 1277 } else { 1278 if (blkno != 0) 1279 panic("snapacct: bad block"); 1280 if (lbn < UFS_NDADDR) 1281 db_assign(ip, lbn, expungetype); 1282 else { 1283 idb_assign(ip, ibp->b_data, 1284 (lbn - UFS_NDADDR) % FFS_NINDIR(fs), expungetype); 1285 bdwrite(ibp); 1286 } 1287 } 1288 if (wbreak > 0 && (++n % wbreak) == 0) { 1289 UFS_WAPBL_END(mp); 1290 error = UFS_WAPBL_BEGIN(mp); 1291 if (error) 1292 return error; 1293 } 1294 } 1295 UFS_WAPBL_END(mp); 1296 return error; 1297} 1298 1299/* 1300 * Account for a set of blocks allocated in a snapshot inode. 1301 */ 1302static int 1303mapacct(struct vnode *vp, void *bap, int oldblkp, int lastblkp, 1304 struct fs *fs, daddr_t lblkno, int expungetype) 1305{ 1306 daddr_t blkno; 1307 struct inode *ip; 1308 struct mount *mp = vp->v_mount; 1309 ino_t inum; 1310 int acctit, error, n; 1311 const int wbreak = blocks_in_journal(VFSTOUFS(mp)->um_fs)/8; 1312 1313 error = UFS_WAPBL_BEGIN(mp); 1314 if (error) 1315 return error; 1316 ip = VTOI(vp); 1317 inum = ip->i_number; 1318 if (lblkno == -1) 1319 acctit = 0; 1320 else 1321 acctit = 1; 1322 for ( n = 0; oldblkp < lastblkp; oldblkp++, lblkno++) { 1323 blkno = idb_get(ip, bap, oldblkp); 1324 if (blkno == 0 || blkno == BLK_NOCOPY) 1325 continue; 1326 if (acctit && expungetype == BLK_SNAP && blkno != BLK_SNAP) 1327 *ip->i_snapblklist++ = lblkno; 1328 if (blkno == BLK_SNAP) 1329 blkno = ffs_blkstofrags(fs, lblkno); 1330 ffs_blkfree_snap(fs, vp, blkno, fs->fs_bsize, inum); 1331 if (wbreak > 0 && (++n % wbreak) == 0) { 1332 UFS_WAPBL_END(mp); 1333 error = UFS_WAPBL_BEGIN(mp); 1334 if (error) 1335 return error; 1336 } 1337 } 1338 UFS_WAPBL_END(mp); 1339 return (0); 1340} 1341 1342/* 1343 * Number of blocks that fit into the journal or zero if not logging. 1344 */ 1345static int 1346blocks_in_journal(struct fs *fs) 1347{ 1348 off_t bpj; 1349 1350 if ((fs->fs_flags & FS_DOWAPBL) == 0) 1351 return 0; 1352 bpj = 1; 1353 if (fs->fs_journal_version == UFS_WAPBL_VERSION) { 1354 switch (fs->fs_journal_location) { 1355 case UFS_WAPBL_JOURNALLOC_END_PARTITION: 1356 bpj = (off_t)fs->fs_journallocs[UFS_WAPBL_EPART_BLKSZ]* 1357 fs->fs_journallocs[UFS_WAPBL_EPART_COUNT]; 1358 break; 1359 case UFS_WAPBL_JOURNALLOC_IN_FILESYSTEM: 1360 bpj = (off_t)fs->fs_journallocs[UFS_WAPBL_INFS_BLKSZ]* 1361 fs->fs_journallocs[UFS_WAPBL_INFS_COUNT]; 1362 break; 1363 } 1364 } 1365 bpj /= fs->fs_bsize; 1366 return (bpj > 0 ? bpj : 1); 1367} 1368#endif /* defined(FFS_NO_SNAPSHOT) */ 1369 1370/* 1371 * Decrement extra reference on snapshot when last name is removed. 1372 * It will not be freed until the last open reference goes away. 1373 */ 1374void 1375ffs_snapgone(struct vnode *vp) 1376{ 1377 struct inode *xp, *ip = VTOI(vp); 1378 struct mount *mp = spec_node_getmountedfs(ip->i_devvp); 1379 struct fs *fs; 1380 struct snap_info *si; 1381 int snaploc; 1382 1383 si = VFSTOUFS(mp)->um_snapinfo; 1384 1385 /* 1386 * Find snapshot in incore list. 1387 */ 1388 mutex_enter(&si->si_lock); 1389 TAILQ_FOREACH(xp, &si->si_snapshots, i_nextsnap) 1390 if (xp == ip) 1391 break; 1392 mutex_exit(&si->si_lock); 1393 if (xp != NULL) 1394 vrele(ITOV(ip)); 1395#ifdef DEBUG 1396 else if (snapdebug) 1397 printf("ffs_snapgone: lost snapshot vnode %llu\n", 1398 (unsigned long long)ip->i_number); 1399#endif 1400 /* 1401 * Delete snapshot inode from superblock. Keep list dense. 1402 */ 1403 mutex_enter(&si->si_lock); 1404 fs = ip->i_fs; 1405 for (snaploc = 0; snaploc < FSMAXSNAP; snaploc++) 1406 if (fs->fs_snapinum[snaploc] == ip->i_number) 1407 break; 1408 if (snaploc < FSMAXSNAP) { 1409 for (snaploc++; snaploc < FSMAXSNAP; snaploc++) { 1410 if (fs->fs_snapinum[snaploc] == 0) 1411 break; 1412 fs->fs_snapinum[snaploc - 1] = fs->fs_snapinum[snaploc]; 1413 } 1414 fs->fs_snapinum[snaploc - 1] = 0; 1415 } 1416 si->si_gen++; 1417 mutex_exit(&si->si_lock); 1418} 1419 1420/* 1421 * Prepare a snapshot file for being removed. 1422 */ 1423void 1424ffs_snapremove(struct vnode *vp) 1425{ 1426 struct inode *ip = VTOI(vp), *xp; 1427 struct vnode *devvp = ip->i_devvp; 1428 struct fs *fs = ip->i_fs; 1429 struct mount *mp = spec_node_getmountedfs(devvp); 1430 struct buf *ibp; 1431 struct snap_info *si; 1432 struct lwp *l = curlwp; 1433 daddr_t numblks, blkno, dblk; 1434 int error, loc, last; 1435 1436 si = VFSTOUFS(mp)->um_snapinfo; 1437 /* 1438 * If active, delete from incore list (this snapshot may 1439 * already have been in the process of being deleted, so 1440 * would not have been active). 1441 * 1442 * Clear copy-on-write flag if last snapshot. 1443 */ 1444 mutex_enter(&si->si_snaplock); 1445 mutex_enter(&si->si_lock); 1446 if (is_active_snapshot(si, ip)) { 1447 TAILQ_REMOVE(&si->si_snapshots, ip, i_nextsnap); 1448 if (TAILQ_FIRST(&si->si_snapshots) != 0) { 1449 /* Roll back the list of preallocated blocks. */ 1450 xp = TAILQ_LAST(&si->si_snapshots, inodelst); 1451 si->si_snapblklist = xp->i_snapblklist; 1452 si->si_gen++; 1453 mutex_exit(&si->si_lock); 1454 mutex_exit(&si->si_snaplock); 1455 } else { 1456 si->si_snapblklist = 0; 1457 si->si_gen++; 1458 mutex_exit(&si->si_lock); 1459 mutex_exit(&si->si_snaplock); 1460 fscow_disestablish(mp, ffs_copyonwrite, devvp); 1461 } 1462 if (ip->i_snapblklist != NULL) { 1463 free(ip->i_snapblklist, M_UFSMNT); 1464 ip->i_snapblklist = NULL; 1465 } 1466 } else { 1467 mutex_exit(&si->si_lock); 1468 mutex_exit(&si->si_snaplock); 1469 } 1470 /* 1471 * Clear all BLK_NOCOPY fields. Pass any block claims to other 1472 * snapshots that want them (see ffs_snapblkfree below). 1473 */ 1474 for (blkno = 1; blkno < UFS_NDADDR; blkno++) { 1475 dblk = db_get(ip, blkno); 1476 if (dblk == BLK_NOCOPY || dblk == BLK_SNAP) 1477 db_assign(ip, blkno, 0); 1478 else if ((dblk == ffs_blkstofrags(fs, blkno) && 1479 ffs_snapblkfree(fs, ip->i_devvp, dblk, fs->fs_bsize, 1480 ip->i_number))) { 1481 DIP_ADD(ip, blocks, -btodb(fs->fs_bsize)); 1482 db_assign(ip, blkno, 0); 1483 } 1484 } 1485 numblks = howmany(ip->i_size, fs->fs_bsize); 1486 for (blkno = UFS_NDADDR; blkno < numblks; blkno += FFS_NINDIR(fs)) { 1487 error = ffs_balloc(vp, ffs_lblktosize(fs, (off_t)blkno), 1488 fs->fs_bsize, l->l_cred, B_METAONLY, &ibp); 1489 if (error) 1490 continue; 1491 if (fs->fs_size - blkno > FFS_NINDIR(fs)) 1492 last = FFS_NINDIR(fs); 1493 else 1494 last = fs->fs_size - blkno; 1495 for (loc = 0; loc < last; loc++) { 1496 dblk = idb_get(ip, ibp->b_data, loc); 1497 if (dblk == BLK_NOCOPY || dblk == BLK_SNAP) 1498 idb_assign(ip, ibp->b_data, loc, 0); 1499 else if (dblk == ffs_blkstofrags(fs, blkno) && 1500 ffs_snapblkfree(fs, ip->i_devvp, dblk, 1501 fs->fs_bsize, ip->i_number)) { 1502 DIP_ADD(ip, blocks, -btodb(fs->fs_bsize)); 1503 idb_assign(ip, ibp->b_data, loc, 0); 1504 } 1505 } 1506 bawrite(ibp); 1507 UFS_WAPBL_END(mp); 1508 error = UFS_WAPBL_BEGIN(mp); 1509 KASSERT(error == 0); 1510 } 1511 /* 1512 * Clear snapshot flag and drop reference. 1513 */ 1514 ip->i_flags &= ~(SF_SNAPSHOT | SF_SNAPINVAL); 1515 DIP_ASSIGN(ip, flags, ip->i_flags); 1516 ip->i_flag |= IN_CHANGE | IN_UPDATE; 1517#if defined(QUOTA) || defined(QUOTA2) 1518 chkdq(ip, DIP(ip, blocks), l->l_cred, FORCE); 1519 chkiq(ip, 1, l->l_cred, FORCE); 1520#endif 1521} 1522 1523/* 1524 * Notification that a block is being freed. Return zero if the free 1525 * should be allowed to proceed. Return non-zero if the snapshot file 1526 * wants to claim the block. The block will be claimed if it is an 1527 * uncopied part of one of the snapshots. It will be freed if it is 1528 * either a BLK_NOCOPY or has already been copied in all of the snapshots. 1529 * If a fragment is being freed, then all snapshots that care about 1530 * it must make a copy since a snapshot file can only claim full sized 1531 * blocks. Note that if more than one snapshot file maps the block, 1532 * we can pick one at random to claim it. Since none of the snapshots 1533 * can change, we are assurred that they will all see the same unmodified 1534 * image. When deleting a snapshot file (see ffs_snapremove above), we 1535 * must push any of these claimed blocks to one of the other snapshots 1536 * that maps it. These claimed blocks are easily identified as they will 1537 * have a block number equal to their logical block number within the 1538 * snapshot. A copied block can never have this property because they 1539 * must always have been allocated from a BLK_NOCOPY location. 1540 */ 1541int 1542ffs_snapblkfree(struct fs *fs, struct vnode *devvp, daddr_t bno, 1543 long size, ino_t inum) 1544{ 1545 struct mount *mp = spec_node_getmountedfs(devvp); 1546 struct buf *ibp; 1547 struct inode *ip; 1548 struct vnode *vp = NULL; 1549 struct snap_info *si; 1550 void *saved_data = NULL; 1551 daddr_t lbn; 1552 daddr_t blkno; 1553 uint32_t gen; 1554 int indiroff = 0, error = 0, claimedblk = 0; 1555 1556 si = VFSTOUFS(mp)->um_snapinfo; 1557 lbn = ffs_fragstoblks(fs, bno); 1558 mutex_enter(&si->si_snaplock); 1559 mutex_enter(&si->si_lock); 1560 si->si_owner = curlwp; 1561 1562retry: 1563 gen = si->si_gen; 1564 TAILQ_FOREACH(ip, &si->si_snapshots, i_nextsnap) { 1565 vp = ITOV(ip); 1566 /* 1567 * Lookup block being written. 1568 */ 1569 if (lbn < UFS_NDADDR) { 1570 blkno = db_get(ip, lbn); 1571 } else { 1572 mutex_exit(&si->si_lock); 1573 error = ffs_balloc(vp, ffs_lblktosize(fs, (off_t)lbn), 1574 fs->fs_bsize, FSCRED, B_METAONLY, &ibp); 1575 if (error) { 1576 mutex_enter(&si->si_lock); 1577 break; 1578 } 1579 indiroff = (lbn - UFS_NDADDR) % FFS_NINDIR(fs); 1580 blkno = idb_get(ip, ibp->b_data, indiroff); 1581 mutex_enter(&si->si_lock); 1582 if (gen != si->si_gen) { 1583 brelse(ibp, 0); 1584 goto retry; 1585 } 1586 } 1587 /* 1588 * Check to see if block needs to be copied. 1589 */ 1590 if (blkno == 0) { 1591 /* 1592 * A block that we map is being freed. If it has not 1593 * been claimed yet, we will claim or copy it (below). 1594 */ 1595 claimedblk = 1; 1596 } else if (blkno == BLK_SNAP) { 1597 /* 1598 * No previous snapshot claimed the block, 1599 * so it will be freed and become a BLK_NOCOPY 1600 * (don't care) for us. 1601 */ 1602 if (claimedblk) 1603 panic("snapblkfree: inconsistent block type"); 1604 if (lbn < UFS_NDADDR) { 1605 db_assign(ip, lbn, BLK_NOCOPY); 1606 ip->i_flag |= IN_CHANGE | IN_UPDATE; 1607 } else { 1608 idb_assign(ip, ibp->b_data, indiroff, 1609 BLK_NOCOPY); 1610 mutex_exit(&si->si_lock); 1611 if (ip->i_nlink > 0) 1612 bwrite(ibp); 1613 else 1614 bdwrite(ibp); 1615 mutex_enter(&si->si_lock); 1616 if (gen != si->si_gen) 1617 goto retry; 1618 } 1619 continue; 1620 } else /* BLK_NOCOPY or default */ { 1621 /* 1622 * If the snapshot has already copied the block 1623 * (default), or does not care about the block, 1624 * it is not needed. 1625 */ 1626 if (lbn >= UFS_NDADDR) 1627 brelse(ibp, 0); 1628 continue; 1629 } 1630 /* 1631 * If this is a full size block, we will just grab it 1632 * and assign it to the snapshot inode. Otherwise we 1633 * will proceed to copy it. See explanation for this 1634 * routine as to why only a single snapshot needs to 1635 * claim this block. 1636 */ 1637 if (size == fs->fs_bsize) { 1638#ifdef DEBUG 1639 if (snapdebug) 1640 printf("%s %llu lbn %" PRId64 1641 "from inum %llu\n", 1642 "Grabonremove: snapino", 1643 (unsigned long long)ip->i_number, 1644 lbn, (unsigned long long)inum); 1645#endif 1646 mutex_exit(&si->si_lock); 1647 if (lbn < UFS_NDADDR) { 1648 db_assign(ip, lbn, bno); 1649 } else { 1650 idb_assign(ip, ibp->b_data, indiroff, bno); 1651 if (ip->i_nlink > 0) 1652 bwrite(ibp); 1653 else 1654 bdwrite(ibp); 1655 } 1656 DIP_ADD(ip, blocks, btodb(size)); 1657 ip->i_flag |= IN_CHANGE | IN_UPDATE; 1658 if (ip->i_nlink > 0 && mp->mnt_wapbl) 1659 error = syncsnap(vp); 1660 else 1661 error = 0; 1662 mutex_enter(&si->si_lock); 1663 si->si_owner = NULL; 1664 mutex_exit(&si->si_lock); 1665 mutex_exit(&si->si_snaplock); 1666 return (error == 0); 1667 } 1668 if (lbn >= UFS_NDADDR) 1669 brelse(ibp, 0); 1670#ifdef DEBUG 1671 if (snapdebug) 1672 printf("%s%llu lbn %" PRId64 " %s %llu size %ld\n", 1673 "Copyonremove: snapino ", 1674 (unsigned long long)ip->i_number, 1675 lbn, "for inum", (unsigned long long)inum, size); 1676#endif 1677 /* 1678 * If we have already read the old block contents, then 1679 * simply copy them to the new block. Note that we need 1680 * to synchronously write snapshots that have not been 1681 * unlinked, and hence will be visible after a crash, 1682 * to ensure their integrity. 1683 */ 1684 mutex_exit(&si->si_lock); 1685 if (saved_data == NULL) { 1686 saved_data = malloc(fs->fs_bsize, M_UFSMNT, M_WAITOK); 1687 error = rwfsblk(vp, B_READ, saved_data, lbn); 1688 if (error) { 1689 free(saved_data, M_UFSMNT); 1690 saved_data = NULL; 1691 mutex_enter(&si->si_lock); 1692 break; 1693 } 1694 } 1695 error = wrsnapblk(vp, saved_data, lbn); 1696 if (error == 0 && ip->i_nlink > 0 && mp->mnt_wapbl) 1697 error = syncsnap(vp); 1698 mutex_enter(&si->si_lock); 1699 if (error) 1700 break; 1701 if (gen != si->si_gen) 1702 goto retry; 1703 } 1704 si->si_owner = NULL; 1705 mutex_exit(&si->si_lock); 1706 mutex_exit(&si->si_snaplock); 1707 if (saved_data) 1708 free(saved_data, M_UFSMNT); 1709 /* 1710 * If we have been unable to allocate a block in which to do 1711 * the copy, then return non-zero so that the fragment will 1712 * not be freed. Although space will be lost, the snapshot 1713 * will stay consistent. 1714 */ 1715 return (error); 1716} 1717 1718/* 1719 * Associate snapshot files when mounting. 1720 */ 1721void 1722ffs_snapshot_mount(struct mount *mp) 1723{ 1724 struct vnode *devvp = VFSTOUFS(mp)->um_devvp; 1725 struct fs *fs = VFSTOUFS(mp)->um_fs; 1726 struct lwp *l = curlwp; 1727 struct vnode *vp; 1728 struct inode *ip, *xp; 1729 struct snap_info *si; 1730 daddr_t snaplistsize, *snapblklist; 1731 int i, error, ns __unused, snaploc, loc; 1732 1733 /* 1734 * No persistent snapshots on apple ufs file systems. 1735 */ 1736 if (UFS_MPISAPPLEUFS(VFSTOUFS(mp))) 1737 return; 1738 1739 si = VFSTOUFS(mp)->um_snapinfo; 1740 ns = UFS_FSNEEDSWAP(fs); 1741 /* 1742 * XXX The following needs to be set before ffs_truncate or 1743 * VOP_READ can be called. 1744 */ 1745 mp->mnt_stat.f_iosize = fs->fs_bsize; 1746 /* 1747 * Process each snapshot listed in the superblock. 1748 */ 1749 vp = NULL; 1750 mutex_enter(&si->si_lock); 1751 for (snaploc = 0; snaploc < FSMAXSNAP; snaploc++) { 1752 if (fs->fs_snapinum[snaploc] == 0) 1753 break; 1754 if ((error = VFS_VGET(mp, fs->fs_snapinum[snaploc], 1755 &vp)) != 0) { 1756 printf("ffs_snapshot_mount: vget failed %d\n", error); 1757 continue; 1758 } 1759 ip = VTOI(vp); 1760 if ((ip->i_flags & (SF_SNAPSHOT | SF_SNAPINVAL)) != 1761 SF_SNAPSHOT) { 1762 printf("ffs_snapshot_mount: non-snapshot inode %d\n", 1763 fs->fs_snapinum[snaploc]); 1764 vput(vp); 1765 vp = NULL; 1766 for (loc = snaploc + 1; loc < FSMAXSNAP; loc++) { 1767 if (fs->fs_snapinum[loc] == 0) 1768 break; 1769 fs->fs_snapinum[loc - 1] = fs->fs_snapinum[loc]; 1770 } 1771 fs->fs_snapinum[loc - 1] = 0; 1772 snaploc--; 1773 continue; 1774 } 1775 1776 /* 1777 * Read the block hints list. Use an empty list on 1778 * read errors. 1779 */ 1780 error = vn_rdwr(UIO_READ, vp, 1781 (void *)&snaplistsize, sizeof(snaplistsize), 1782 ffs_lblktosize(fs, howmany(fs->fs_size, fs->fs_frag)), 1783 UIO_SYSSPACE, IO_NODELOCKED|IO_UNIT|IO_ALTSEMANTICS, 1784 l->l_cred, NULL, NULL); 1785 if (error) { 1786 printf("ffs_snapshot_mount: read_1 failed %d\n", error); 1787 snaplistsize = 1; 1788 } else 1789 snaplistsize = ufs_rw64(snaplistsize, ns); 1790 snapblklist = malloc( 1791 snaplistsize * sizeof(daddr_t), M_UFSMNT, M_WAITOK); 1792 if (error) 1793 snapblklist[0] = 1; 1794 else { 1795 error = vn_rdwr(UIO_READ, vp, (void *)snapblklist, 1796 snaplistsize * sizeof(daddr_t), 1797 ffs_lblktosize(fs, howmany(fs->fs_size, fs->fs_frag)), 1798 UIO_SYSSPACE, IO_NODELOCKED|IO_UNIT|IO_ALTSEMANTICS, 1799 l->l_cred, NULL, NULL); 1800 for (i = 0; i < snaplistsize; i++) 1801 snapblklist[i] = ufs_rw64(snapblklist[i], ns); 1802 if (error) { 1803 printf("ffs_snapshot_mount: read_2 failed %d\n", 1804 error); 1805 snapblklist[0] = 1; 1806 } 1807 } 1808 ip->i_snapblklist = &snapblklist[0]; 1809 1810 /* 1811 * Link it onto the active snapshot list. 1812 */ 1813 if (is_active_snapshot(si, ip)) 1814 panic("ffs_snapshot_mount: %"PRIu64" already on list", 1815 ip->i_number); 1816 else 1817 TAILQ_INSERT_TAIL(&si->si_snapshots, ip, i_nextsnap); 1818 vp->v_vflag |= VV_SYSTEM; 1819 VOP_UNLOCK(vp); 1820 } 1821 /* 1822 * No usable snapshots found. 1823 */ 1824 if (vp == NULL) { 1825 mutex_exit(&si->si_lock); 1826 return; 1827 } 1828 /* 1829 * Attach the block hints list. We always want to 1830 * use the list from the newest snapshot. 1831 */ 1832 xp = TAILQ_LAST(&si->si_snapshots, inodelst); 1833 si->si_snapblklist = xp->i_snapblklist; 1834 fscow_establish(mp, ffs_copyonwrite, devvp); 1835 si->si_gen++; 1836 mutex_exit(&si->si_lock); 1837} 1838 1839/* 1840 * Disassociate snapshot files when unmounting. 1841 */ 1842void 1843ffs_snapshot_unmount(struct mount *mp) 1844{ 1845 struct vnode *devvp = VFSTOUFS(mp)->um_devvp; 1846 struct inode *xp; 1847 struct vnode *vp = NULL; 1848 struct snap_info *si; 1849 1850 si = VFSTOUFS(mp)->um_snapinfo; 1851 mutex_enter(&si->si_lock); 1852 while ((xp = TAILQ_FIRST(&si->si_snapshots)) != 0) { 1853 vp = ITOV(xp); 1854 TAILQ_REMOVE(&si->si_snapshots, xp, i_nextsnap); 1855 if (xp->i_snapblklist == si->si_snapblklist) 1856 si->si_snapblklist = NULL; 1857 free(xp->i_snapblklist, M_UFSMNT); 1858 if (xp->i_nlink > 0) { 1859 si->si_gen++; 1860 mutex_exit(&si->si_lock); 1861 vrele(vp); 1862 mutex_enter(&si->si_lock); 1863 } 1864 } 1865 si->si_gen++; 1866 mutex_exit(&si->si_lock); 1867 if (vp) 1868 fscow_disestablish(mp, ffs_copyonwrite, devvp); 1869} 1870 1871/* 1872 * Check for need to copy block that is about to be written, 1873 * copying the block if necessary. 1874 */ 1875static int 1876ffs_copyonwrite(void *v, struct buf *bp, bool data_valid) 1877{ 1878 struct fs *fs; 1879 struct inode *ip; 1880 struct vnode *devvp = v, *vp = NULL; 1881 struct mount *mp = spec_node_getmountedfs(devvp); 1882 struct snap_info *si; 1883 void *saved_data = NULL; 1884 daddr_t lbn, blkno, *snapblklist; 1885 uint32_t gen; 1886 int lower, upper, mid, snapshot_locked = 0, error = 0; 1887 1888 /* 1889 * Check for valid snapshots. 1890 */ 1891 si = VFSTOUFS(mp)->um_snapinfo; 1892 mutex_enter(&si->si_lock); 1893 ip = TAILQ_FIRST(&si->si_snapshots); 1894 if (ip == NULL) { 1895 mutex_exit(&si->si_lock); 1896 return 0; 1897 } 1898 /* 1899 * First check to see if it is after the file system, 1900 * in the journal or in the preallocated list. 1901 * By doing these checks we avoid several potential deadlocks. 1902 */ 1903 fs = ip->i_fs; 1904 lbn = ffs_fragstoblks(fs, FFS_DBTOFSB(fs, bp->b_blkno)); 1905 if (bp->b_blkno >= FFS_FSBTODB(fs, fs->fs_size)) { 1906 mutex_exit(&si->si_lock); 1907 return 0; 1908 } 1909 if ((fs->fs_flags & FS_DOWAPBL) && 1910 fs->fs_journal_location == UFS_WAPBL_JOURNALLOC_IN_FILESYSTEM) { 1911 off_t blk_off, log_start, log_end; 1912 1913 log_start = (off_t)fs->fs_journallocs[UFS_WAPBL_INFS_ADDR] * 1914 fs->fs_journallocs[UFS_WAPBL_INFS_BLKSZ]; 1915 log_end = log_start + fs->fs_journallocs[UFS_WAPBL_INFS_COUNT] * 1916 fs->fs_journallocs[UFS_WAPBL_INFS_BLKSZ]; 1917 blk_off = dbtob(bp->b_blkno); 1918 if (blk_off >= log_start && blk_off < log_end) { 1919 mutex_exit(&si->si_lock); 1920 return 0; 1921 } 1922 } 1923 snapblklist = si->si_snapblklist; 1924 upper = (snapblklist != NULL ? snapblklist[0] - 1 : 0); 1925 lower = 1; 1926 while (lower <= upper) { 1927 mid = (lower + upper) / 2; 1928 if (snapblklist[mid] == lbn) 1929 break; 1930 if (snapblklist[mid] < lbn) 1931 lower = mid + 1; 1932 else 1933 upper = mid - 1; 1934 } 1935 if (lower <= upper) { 1936 mutex_exit(&si->si_lock); 1937 return 0; 1938 } 1939 /* 1940 * Not in the precomputed list, so check the snapshots. 1941 */ 1942 if (si->si_owner != curlwp) { 1943 if (!mutex_tryenter(&si->si_snaplock)) { 1944 mutex_exit(&si->si_lock); 1945 mutex_enter(&si->si_snaplock); 1946 mutex_enter(&si->si_lock); 1947 } 1948 si->si_owner = curlwp; 1949 snapshot_locked = 1; 1950 } 1951 if (data_valid && bp->b_bcount == fs->fs_bsize) 1952 saved_data = bp->b_data; 1953retry: 1954 gen = si->si_gen; 1955 TAILQ_FOREACH(ip, &si->si_snapshots, i_nextsnap) { 1956 vp = ITOV(ip); 1957 /* 1958 * We ensure that everything of our own that needs to be 1959 * copied will be done at the time that ffs_snapshot is 1960 * called. Thus we can skip the check here which can 1961 * deadlock in doing the lookup in ffs_balloc. 1962 */ 1963 if (bp->b_vp == vp) 1964 continue; 1965 /* 1966 * Check to see if block needs to be copied. 1967 */ 1968 if (lbn < UFS_NDADDR) { 1969 blkno = db_get(ip, lbn); 1970 } else { 1971 mutex_exit(&si->si_lock); 1972 blkno = 0; /* XXX: GCC */ 1973 if ((error = snapblkaddr(vp, lbn, &blkno)) != 0) { 1974 mutex_enter(&si->si_lock); 1975 break; 1976 } 1977 mutex_enter(&si->si_lock); 1978 if (gen != si->si_gen) 1979 goto retry; 1980 } 1981#ifdef DIAGNOSTIC 1982 if (blkno == BLK_SNAP && bp->b_lblkno >= 0) 1983 panic("ffs_copyonwrite: bad copy block"); 1984#endif 1985 if (blkno != 0) 1986 continue; 1987 1988 if (curlwp == uvm.pagedaemon_lwp) { 1989 error = ENOMEM; 1990 break; 1991 } 1992 /* Only one level of recursion allowed. */ 1993 KASSERT(snapshot_locked); 1994 /* 1995 * Allocate the block into which to do the copy. Since 1996 * multiple processes may all try to copy the same block, 1997 * we have to recheck our need to do a copy if we sleep 1998 * waiting for the lock. 1999 * 2000 * Because all snapshots on a filesystem share a single 2001 * lock, we ensure that we will never be in competition 2002 * with another process to allocate a block. 2003 */ 2004#ifdef DEBUG 2005 if (snapdebug) { 2006 printf("Copyonwrite: snapino %llu lbn %" PRId64 " for ", 2007 (unsigned long long)ip->i_number, lbn); 2008 if (bp->b_vp == devvp) 2009 printf("fs metadata"); 2010 else 2011 printf("inum %llu", (unsigned long long) 2012 VTOI(bp->b_vp)->i_number); 2013 printf(" lblkno %" PRId64 "\n", bp->b_lblkno); 2014 } 2015#endif 2016 /* 2017 * If we have already read the old block contents, then 2018 * simply copy them to the new block. Note that we need 2019 * to synchronously write snapshots that have not been 2020 * unlinked, and hence will be visible after a crash, 2021 * to ensure their integrity. 2022 */ 2023 mutex_exit(&si->si_lock); 2024 if (saved_data == NULL) { 2025 saved_data = malloc(fs->fs_bsize, M_UFSMNT, M_WAITOK); 2026 error = rwfsblk(vp, B_READ, saved_data, lbn); 2027 if (error) { 2028 free(saved_data, M_UFSMNT); 2029 saved_data = NULL; 2030 mutex_enter(&si->si_lock); 2031 break; 2032 } 2033 } 2034 error = wrsnapblk(vp, saved_data, lbn); 2035 if (error == 0 && ip->i_nlink > 0 && mp->mnt_wapbl) 2036 error = syncsnap(vp); 2037 mutex_enter(&si->si_lock); 2038 if (error) 2039 break; 2040 if (gen != si->si_gen) 2041 goto retry; 2042 } 2043 /* 2044 * Note that we need to synchronously write snapshots that 2045 * have not been unlinked, and hence will be visible after 2046 * a crash, to ensure their integrity. 2047 */ 2048 if (snapshot_locked) { 2049 si->si_owner = NULL; 2050 mutex_exit(&si->si_lock); 2051 mutex_exit(&si->si_snaplock); 2052 } else 2053 mutex_exit(&si->si_lock); 2054 if (saved_data && saved_data != bp->b_data) 2055 free(saved_data, M_UFSMNT); 2056 return error; 2057} 2058 2059/* 2060 * Read from a snapshot. 2061 */ 2062int 2063ffs_snapshot_read(struct vnode *vp, struct uio *uio, int ioflag) 2064{ 2065 struct inode *ip = VTOI(vp); 2066 struct fs *fs = ip->i_fs; 2067 struct snap_info *si = VFSTOUFS(vp->v_mount)->um_snapinfo; 2068 struct buf *bp; 2069 daddr_t lbn, nextlbn; 2070 off_t fsbytes, bytesinfile; 2071 long size, xfersize, blkoffset; 2072 int error; 2073 2074 fstrans_start(vp->v_mount, FSTRANS_SHARED); 2075 mutex_enter(&si->si_snaplock); 2076 2077 if (ioflag & IO_ALTSEMANTICS) 2078 fsbytes = ip->i_size; 2079 else 2080 fsbytes = ffs_lfragtosize(fs, fs->fs_size); 2081 for (error = 0, bp = NULL; uio->uio_resid > 0; bp = NULL) { 2082 bytesinfile = fsbytes - uio->uio_offset; 2083 if (bytesinfile <= 0) 2084 break; 2085 lbn = ffs_lblkno(fs, uio->uio_offset); 2086 nextlbn = lbn + 1; 2087 size = fs->fs_bsize; 2088 blkoffset = ffs_blkoff(fs, uio->uio_offset); 2089 xfersize = MIN(MIN(fs->fs_bsize - blkoffset, uio->uio_resid), 2090 bytesinfile); 2091 2092 if (ffs_lblktosize(fs, nextlbn + 1) >= fsbytes) { 2093 if (ffs_lblktosize(fs, lbn) + size > fsbytes) 2094 size = ffs_fragroundup(fs, 2095 fsbytes - ffs_lblktosize(fs, lbn)); 2096 error = bread(vp, lbn, size, 0, &bp); 2097 } else { 2098 int nextsize = fs->fs_bsize; 2099 error = breadn(vp, lbn, 2100 size, &nextlbn, &nextsize, 1, 0, &bp); 2101 } 2102 if (error) 2103 break; 2104 2105 /* 2106 * We should only get non-zero b_resid when an I/O error 2107 * has occurred, which should cause us to break above. 2108 * However, if the short read did not cause an error, 2109 * then we want to ensure that we do not uiomove bad 2110 * or uninitialized data. 2111 */ 2112 size -= bp->b_resid; 2113 if (size < blkoffset + xfersize) { 2114 xfersize = size - blkoffset; 2115 if (xfersize <= 0) 2116 break; 2117 } 2118 error = uiomove((char *)bp->b_data + blkoffset, xfersize, uio); 2119 if (error) 2120 break; 2121 brelse(bp, BC_AGE); 2122 } 2123 if (bp != NULL) 2124 brelse(bp, BC_AGE); 2125 2126 mutex_exit(&si->si_snaplock); 2127 fstrans_done(vp->v_mount); 2128 return error; 2129} 2130 2131/* 2132 * Lookup a snapshots data block address. 2133 * Simpler than UFS_BALLOC() as we know all metadata is already allocated 2134 * and safe even for the pagedaemon where we cannot bread(). 2135 */ 2136static int 2137snapblkaddr(struct vnode *vp, daddr_t lbn, daddr_t *res) 2138{ 2139 struct indir indirs[UFS_NIADDR + 2]; 2140 struct inode *ip = VTOI(vp); 2141 struct fs *fs = ip->i_fs; 2142 struct buf *bp; 2143 int error, num; 2144 2145 KASSERT(lbn >= 0); 2146 2147 if (lbn < UFS_NDADDR) { 2148 *res = db_get(ip, lbn); 2149 return 0; 2150 } 2151 if ((error = ufs_getlbns(vp, lbn, indirs, &num)) != 0) 2152 return error; 2153 if (curlwp == uvm.pagedaemon_lwp) { 2154 mutex_enter(&bufcache_lock); 2155 bp = incore(vp, indirs[num-1].in_lbn); 2156 if (bp && (bp->b_oflags & (BO_DONE | BO_DELWRI))) { 2157 *res = idb_get(ip, bp->b_data, indirs[num-1].in_off); 2158 error = 0; 2159 } else 2160 error = ENOMEM; 2161 mutex_exit(&bufcache_lock); 2162 return error; 2163 } 2164 error = bread(vp, indirs[num-1].in_lbn, fs->fs_bsize, 0, &bp); 2165 if (error == 0) { 2166 *res = idb_get(ip, bp->b_data, indirs[num-1].in_off); 2167 brelse(bp, 0); 2168 } 2169 2170 return error; 2171} 2172 2173/* 2174 * Read or write the specified block of the filesystem vp resides on 2175 * from or to the disk bypassing the buffer cache. 2176 */ 2177static int 2178rwfsblk(struct vnode *vp, int flags, void *data, daddr_t lbn) 2179{ 2180 int error; 2181 struct inode *ip = VTOI(vp); 2182 struct fs *fs = ip->i_fs; 2183 struct buf *nbp; 2184 2185 nbp = getiobuf(NULL, true); 2186 nbp->b_flags = flags; 2187 nbp->b_bcount = nbp->b_bufsize = fs->fs_bsize; 2188 nbp->b_error = 0; 2189 nbp->b_data = data; 2190 nbp->b_blkno = nbp->b_rawblkno = FFS_FSBTODB(fs, ffs_blkstofrags(fs, lbn)); 2191 nbp->b_proc = NULL; 2192 nbp->b_dev = ip->i_devvp->v_rdev; 2193 SET(nbp->b_cflags, BC_BUSY); /* mark buffer busy */ 2194 2195 bdev_strategy(nbp); 2196 2197 error = biowait(nbp); 2198 2199 putiobuf(nbp); 2200 2201 return error; 2202} 2203 2204/* 2205 * Write all dirty buffers to disk and invalidate them. 2206 */ 2207static int 2208syncsnap(struct vnode *vp) 2209{ 2210 int error; 2211 buf_t *bp; 2212 struct fs *fs = VTOI(vp)->i_fs; 2213 2214 mutex_enter(&bufcache_lock); 2215 while ((bp = LIST_FIRST(&vp->v_dirtyblkhd))) { 2216 error = bbusy(bp, false, 0, NULL); 2217 if (error == EPASSTHROUGH) 2218 continue; 2219 else if (error != 0) { 2220 mutex_exit(&bufcache_lock); 2221 return error; 2222 } 2223 KASSERT(bp->b_bcount == fs->fs_bsize); 2224 mutex_exit(&bufcache_lock); 2225 error = rwfsblk(vp, B_WRITE, bp->b_data, 2226 ffs_fragstoblks(fs, FFS_DBTOFSB(fs, bp->b_blkno))); 2227 brelse(bp, BC_INVAL | BC_VFLUSH); 2228 if (error) 2229 return error; 2230 mutex_enter(&bufcache_lock); 2231 } 2232 mutex_exit(&bufcache_lock); 2233 2234 return 0; 2235} 2236 2237/* 2238 * Write the specified block to a snapshot. 2239 */ 2240static int 2241wrsnapblk(struct vnode *vp, void *data, daddr_t lbn) 2242{ 2243 struct inode *ip = VTOI(vp); 2244 struct fs *fs = ip->i_fs; 2245 struct buf *bp; 2246 int error; 2247 2248 error = ffs_balloc(vp, ffs_lblktosize(fs, (off_t)lbn), fs->fs_bsize, 2249 FSCRED, (ip->i_nlink > 0 ? B_SYNC : 0), &bp); 2250 if (error) 2251 return error; 2252 memcpy(bp->b_data, data, fs->fs_bsize); 2253 if (ip->i_nlink > 0) 2254 error = bwrite(bp); 2255 else 2256 bawrite(bp); 2257 2258 return error; 2259} 2260 2261/* 2262 * Check if this inode is present on the active snapshot list. 2263 * Must be called with snapinfo locked. 2264 */ 2265static inline bool 2266is_active_snapshot(struct snap_info *si, struct inode *ip) 2267{ 2268 struct inode *xp; 2269 2270 KASSERT(mutex_owned(&si->si_lock)); 2271 2272 TAILQ_FOREACH(xp, &si->si_snapshots, i_nextsnap) 2273 if (xp == ip) 2274 return true; 2275 return false; 2276} 2277 2278/* 2279 * Get/Put direct block from inode or buffer containing disk addresses. Take 2280 * care for fs type (UFS1/UFS2) and byte swapping. These functions should go 2281 * into a global include. 2282 */ 2283static inline daddr_t 2284db_get(struct inode *ip, int loc) 2285{ 2286 if (ip->i_ump->um_fstype == UFS1) 2287 return ufs_rw32(ip->i_ffs1_db[loc], UFS_IPNEEDSWAP(ip)); 2288 else 2289 return ufs_rw64(ip->i_ffs2_db[loc], UFS_IPNEEDSWAP(ip)); 2290} 2291 2292static inline void 2293db_assign(struct inode *ip, int loc, daddr_t val) 2294{ 2295 if (ip->i_ump->um_fstype == UFS1) 2296 ip->i_ffs1_db[loc] = ufs_rw32(val, UFS_IPNEEDSWAP(ip)); 2297 else 2298 ip->i_ffs2_db[loc] = ufs_rw64(val, UFS_IPNEEDSWAP(ip)); 2299} 2300 2301__unused static inline daddr_t 2302ib_get(struct inode *ip, int loc) 2303{ 2304 if (ip->i_ump->um_fstype == UFS1) 2305 return ufs_rw32(ip->i_ffs1_ib[loc], UFS_IPNEEDSWAP(ip)); 2306 else 2307 return ufs_rw64(ip->i_ffs2_ib[loc], UFS_IPNEEDSWAP(ip)); 2308} 2309 2310static inline daddr_t 2311idb_get(struct inode *ip, void *bf, int loc) 2312{ 2313 if (ip->i_ump->um_fstype == UFS1) 2314 return ufs_rw32(((int32_t *)(bf))[loc], UFS_IPNEEDSWAP(ip)); 2315 else 2316 return ufs_rw64(((int64_t *)(bf))[loc], UFS_IPNEEDSWAP(ip)); 2317} 2318 2319static inline void 2320idb_assign(struct inode *ip, void *bf, int loc, daddr_t val) 2321{ 2322 if (ip->i_ump->um_fstype == UFS1) 2323 ((int32_t *)(bf))[loc] = ufs_rw32(val, UFS_IPNEEDSWAP(ip)); 2324 else 2325 ((int64_t *)(bf))[loc] = ufs_rw64(val, UFS_IPNEEDSWAP(ip)); 2326} 2327