1 /*- 2 * Copyright 2000 Marshall Kirk McKusick. All Rights Reserved. 3 * 4 * Further information about snapshots can be obtained from: 5 * 6 * Marshall Kirk McKusick http://www.mckusick.com/softdep/ 7 * 1614 Oxford Street mckusick@mckusick.com 8 * Berkeley, CA 94709-1608 +1-510-843-9542 9 * USA 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 21 * THIS SOFTWARE IS PROVIDED BY MARSHALL KIRK MCKUSICK ``AS IS'' AND ANY 22 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 23 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 24 * DISCLAIMED. IN NO EVENT SHALL MARSHALL KIRK MCKUSICK BE LIABLE FOR 25 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)ffs_snapshot.c 8.11 (McKusick) 7/23/00 34 */ 35 36 #include <sys/cdefs.h> 37 __FBSDID("$FreeBSD$"); 38 39 #include "opt_quota.h" 40 41 #include <sys/param.h> 42 #include <sys/kernel.h> 43 #include <sys/systm.h> 44 #include <sys/conf.h> 45 #include <sys/bio.h> 46 #include <sys/buf.h> 47 #include <sys/fcntl.h> 48 #include <sys/proc.h> 49 #include <sys/namei.h> 50 #include <sys/sched.h> 51 #include <sys/stat.h> 52 #include <sys/malloc.h> 53 #include <sys/mount.h> 54 #include <sys/resource.h> 55 #include <sys/resourcevar.h> 56 #include <sys/rwlock.h> 57 #include <sys/vnode.h> 58 59 #include <geom/geom.h> 60 61 #include <ufs/ufs/extattr.h> 62 #include <ufs/ufs/quota.h> 63 #include <ufs/ufs/ufsmount.h> 64 #include <ufs/ufs/inode.h> 65 #include <ufs/ufs/ufs_extern.h> 66 67 #include <ufs/ffs/fs.h> 68 #include <ufs/ffs/ffs_extern.h> 69 70 #define KERNCRED thread0.td_ucred 71 #define DEBUG 1 72 73 #include "opt_ffs.h" 74 75 #ifdef NO_FFS_SNAPSHOT 76 int 77 ffs_snapshot(mp, snapfile) 78 struct mount *mp; 79 char *snapfile; 80 { 81 return (EINVAL); 82 } 83 84 int 85 ffs_snapblkfree(fs, devvp, bno, size, inum, vtype, wkhd) 86 struct fs *fs; 87 struct vnode *devvp; 88 ufs2_daddr_t bno; 89 long size; 90 ino_t inum; 91 enum vtype vtype; 92 struct workhead *wkhd; 93 { 94 return (EINVAL); 95 } 96 97 void 98 ffs_snapremove(vp) 99 struct vnode *vp; 100 { 101 } 102 103 void 104 ffs_snapshot_mount(mp) 105 struct mount *mp; 106 { 107 } 108 109 void 110 ffs_snapshot_unmount(mp) 111 struct mount *mp; 112 { 113 } 114 115 void 116 ffs_snapgone(ip) 117 struct inode *ip; 118 { 119 } 120 121 int 122 ffs_copyonwrite(devvp, bp) 123 struct vnode *devvp; 124 struct buf *bp; 125 { 126 return (EINVAL); 127 } 128 129 void 130 ffs_sync_snap(mp, waitfor) 131 struct mount *mp; 132 int waitfor; 133 { 134 } 135 136 #else 137 FEATURE(ffs_snapshot, "FFS snapshot support"); 138 139 LIST_HEAD(, snapdata) snapfree; 140 static struct mtx snapfree_lock; 141 MTX_SYSINIT(ffs_snapfree, &snapfree_lock, "snapdata free list", MTX_DEF); 142 143 static int cgaccount(int, struct vnode *, struct buf *, int); 144 static int expunge_ufs1(struct vnode *, struct inode *, struct fs *, 145 int (*)(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *, struct fs *, 146 ufs_lbn_t, int), int, int); 147 static int indiracct_ufs1(struct vnode *, struct vnode *, int, 148 ufs1_daddr_t, ufs_lbn_t, ufs_lbn_t, ufs_lbn_t, ufs_lbn_t, struct fs *, 149 int (*)(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *, struct fs *, 150 ufs_lbn_t, int), int); 151 static int fullacct_ufs1(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *, 152 struct fs *, ufs_lbn_t, int); 153 static int snapacct_ufs1(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *, 154 struct fs *, ufs_lbn_t, int); 155 static int mapacct_ufs1(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *, 156 struct fs *, ufs_lbn_t, int); 157 static int expunge_ufs2(struct vnode *, struct inode *, struct fs *, 158 int (*)(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *, struct fs *, 159 ufs_lbn_t, int), int, int); 160 static int indiracct_ufs2(struct vnode *, struct vnode *, int, 161 ufs2_daddr_t, ufs_lbn_t, ufs_lbn_t, ufs_lbn_t, ufs_lbn_t, struct fs *, 162 int (*)(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *, struct fs *, 163 ufs_lbn_t, int), int); 164 static int fullacct_ufs2(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *, 165 struct fs *, ufs_lbn_t, int); 166 static int snapacct_ufs2(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *, 167 struct fs *, ufs_lbn_t, int); 168 static int mapacct_ufs2(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *, 169 struct fs *, ufs_lbn_t, int); 170 static int readblock(struct vnode *vp, struct buf *, ufs2_daddr_t); 171 static void try_free_snapdata(struct vnode *devvp); 172 static struct snapdata *ffs_snapdata_acquire(struct vnode *devvp); 173 static int ffs_bp_snapblk(struct vnode *, struct buf *); 174 175 /* 176 * To ensure the consistency of snapshots across crashes, we must 177 * synchronously write out copied blocks before allowing the 178 * originals to be modified. Because of the rather severe speed 179 * penalty that this imposes, the code normally only ensures 180 * persistence for the filesystem metadata contained within a 181 * snapshot. Setting the following flag allows this crash 182 * persistence to be enabled for file contents. 183 */ 184 int dopersistence = 0; 185 186 #ifdef DEBUG 187 #include <sys/sysctl.h> 188 SYSCTL_INT(_debug, OID_AUTO, dopersistence, CTLFLAG_RW, &dopersistence, 0, ""); 189 static int snapdebug = 0; 190 SYSCTL_INT(_debug, OID_AUTO, snapdebug, CTLFLAG_RW, &snapdebug, 0, ""); 191 int collectsnapstats = 0; 192 SYSCTL_INT(_debug, OID_AUTO, collectsnapstats, CTLFLAG_RW, &collectsnapstats, 193 0, ""); 194 #endif /* DEBUG */ 195 196 /* 197 * Create a snapshot file and initialize it for the filesystem. 198 */ 199 int 200 ffs_snapshot(mp, snapfile) 201 struct mount *mp; 202 char *snapfile; 203 { 204 ufs2_daddr_t numblks, blkno, *blkp, *snapblklist; 205 int error, cg, snaploc; 206 int i, size, len, loc; 207 ufs2_daddr_t blockno; 208 uint64_t flag; 209 struct timespec starttime = {0, 0}, endtime; 210 char saved_nice = 0; 211 long redo = 0, snaplistsize = 0; 212 int32_t *lp; 213 void *space; 214 struct fs *copy_fs = NULL, *fs; 215 struct thread *td = curthread; 216 struct inode *ip, *xp; 217 struct buf *bp, *nbp, *ibp; 218 struct nameidata nd; 219 struct mount *wrtmp; 220 struct vattr vat; 221 struct vnode *vp, *xvp, *mvp, *devvp; 222 struct uio auio; 223 struct iovec aiov; 224 struct snapdata *sn; 225 struct ufsmount *ump; 226 227 ump = VFSTOUFS(mp); 228 fs = ump->um_fs; 229 sn = NULL; 230 /* 231 * At the moment, journaled soft updates cannot support 232 * taking snapshots. 233 */ 234 if (MOUNTEDSUJ(mp)) { 235 vfs_mount_error(mp, "%s: Snapshots are not yet supported when " 236 "running with journaled soft updates", fs->fs_fsmnt); 237 return (EOPNOTSUPP); 238 } 239 MNT_ILOCK(mp); 240 flag = mp->mnt_flag; 241 MNT_IUNLOCK(mp); 242 /* 243 * Need to serialize access to snapshot code per filesystem. 244 */ 245 /* 246 * Assign a snapshot slot in the superblock. 247 */ 248 UFS_LOCK(ump); 249 for (snaploc = 0; snaploc < FSMAXSNAP; snaploc++) 250 if (fs->fs_snapinum[snaploc] == 0) 251 break; 252 UFS_UNLOCK(ump); 253 if (snaploc == FSMAXSNAP) 254 return (ENOSPC); 255 /* 256 * Create the snapshot file. 257 */ 258 restart: 259 NDINIT(&nd, CREATE, LOCKPARENT | LOCKLEAF | NOCACHE, UIO_SYSSPACE, 260 snapfile, td); 261 if ((error = namei(&nd)) != 0) 262 return (error); 263 if (nd.ni_vp != NULL) { 264 vput(nd.ni_vp); 265 error = EEXIST; 266 } 267 if (nd.ni_dvp->v_mount != mp) 268 error = EXDEV; 269 if (error) { 270 NDFREE(&nd, NDF_ONLY_PNBUF); 271 if (nd.ni_dvp == nd.ni_vp) 272 vrele(nd.ni_dvp); 273 else 274 vput(nd.ni_dvp); 275 return (error); 276 } 277 VATTR_NULL(&vat); 278 vat.va_type = VREG; 279 vat.va_mode = S_IRUSR; 280 vat.va_vaflags |= VA_EXCLUSIVE; 281 if (VOP_GETWRITEMOUNT(nd.ni_dvp, &wrtmp)) 282 wrtmp = NULL; 283 if (wrtmp != mp) 284 panic("ffs_snapshot: mount mismatch"); 285 vfs_rel(wrtmp); 286 if (vn_start_write(NULL, &wrtmp, V_NOWAIT) != 0) { 287 NDFREE(&nd, NDF_ONLY_PNBUF); 288 vput(nd.ni_dvp); 289 if ((error = vn_start_write(NULL, &wrtmp, 290 V_XSLEEP | PCATCH)) != 0) 291 return (error); 292 goto restart; 293 } 294 error = VOP_CREATE(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vat); 295 VOP_UNLOCK(nd.ni_dvp, 0); 296 if (error) { 297 NDFREE(&nd, NDF_ONLY_PNBUF); 298 vn_finished_write(wrtmp); 299 vrele(nd.ni_dvp); 300 return (error); 301 } 302 vp = nd.ni_vp; 303 vp->v_vflag |= VV_SYSTEM; 304 ip = VTOI(vp); 305 devvp = ITODEVVP(ip); 306 /* 307 * Allocate and copy the last block contents so as to be able 308 * to set size to that of the filesystem. 309 */ 310 numblks = howmany(fs->fs_size, fs->fs_frag); 311 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)(numblks - 1)), 312 fs->fs_bsize, KERNCRED, BA_CLRBUF, &bp); 313 if (error) 314 goto out; 315 ip->i_size = lblktosize(fs, (off_t)numblks); 316 DIP_SET(ip, i_size, ip->i_size); 317 ip->i_flag |= IN_CHANGE | IN_UPDATE; 318 error = readblock(vp, bp, numblks - 1); 319 bawrite(bp); 320 if (error != 0) 321 goto out; 322 /* 323 * Preallocate critical data structures so that we can copy 324 * them in without further allocation after we suspend all 325 * operations on the filesystem. We would like to just release 326 * the allocated buffers without writing them since they will 327 * be filled in below once we are ready to go, but this upsets 328 * the soft update code, so we go ahead and write the new buffers. 329 * 330 * Allocate all indirect blocks and mark all of them as not 331 * needing to be copied. 332 */ 333 for (blkno = UFS_NDADDR; blkno < numblks; blkno += NINDIR(fs)) { 334 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)blkno), 335 fs->fs_bsize, td->td_ucred, BA_METAONLY, &ibp); 336 if (error) 337 goto out; 338 bawrite(ibp); 339 } 340 /* 341 * Allocate copies for the superblock and its summary information. 342 */ 343 error = UFS_BALLOC(vp, fs->fs_sblockloc, fs->fs_sbsize, KERNCRED, 344 0, &nbp); 345 if (error) 346 goto out; 347 bawrite(nbp); 348 blkno = fragstoblks(fs, fs->fs_csaddr); 349 len = howmany(fs->fs_cssize, fs->fs_bsize); 350 for (loc = 0; loc < len; loc++) { 351 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)(blkno + loc)), 352 fs->fs_bsize, KERNCRED, 0, &nbp); 353 if (error) 354 goto out; 355 bawrite(nbp); 356 } 357 /* 358 * Allocate all cylinder group blocks. 359 */ 360 for (cg = 0; cg < fs->fs_ncg; cg++) { 361 error = UFS_BALLOC(vp, lfragtosize(fs, cgtod(fs, cg)), 362 fs->fs_bsize, KERNCRED, 0, &nbp); 363 if (error) 364 goto out; 365 bawrite(nbp); 366 if (cg % 10 == 0) 367 ffs_syncvnode(vp, MNT_WAIT, 0); 368 } 369 /* 370 * Copy all the cylinder group maps. Although the 371 * filesystem is still active, we hope that only a few 372 * cylinder groups will change between now and when we 373 * suspend operations. Thus, we will be able to quickly 374 * touch up the few cylinder groups that changed during 375 * the suspension period. 376 */ 377 len = howmany(fs->fs_ncg, NBBY); 378 space = malloc(len, M_DEVBUF, M_WAITOK|M_ZERO); 379 UFS_LOCK(ump); 380 fs->fs_active = space; 381 UFS_UNLOCK(ump); 382 for (cg = 0; cg < fs->fs_ncg; cg++) { 383 error = UFS_BALLOC(vp, lfragtosize(fs, cgtod(fs, cg)), 384 fs->fs_bsize, KERNCRED, 0, &nbp); 385 if (error) 386 goto out; 387 error = cgaccount(cg, vp, nbp, 1); 388 bawrite(nbp); 389 if (cg % 10 == 0) 390 ffs_syncvnode(vp, MNT_WAIT, 0); 391 if (error) 392 goto out; 393 } 394 /* 395 * Change inode to snapshot type file. 396 */ 397 ip->i_flags |= SF_SNAPSHOT; 398 DIP_SET(ip, i_flags, ip->i_flags); 399 ip->i_flag |= IN_CHANGE | IN_UPDATE; 400 /* 401 * Ensure that the snapshot is completely on disk. 402 * Since we have marked it as a snapshot it is safe to 403 * unlock it as no process will be allowed to write to it. 404 */ 405 if ((error = ffs_syncvnode(vp, MNT_WAIT, 0)) != 0) 406 goto out; 407 VOP_UNLOCK(vp, 0); 408 /* 409 * All allocations are done, so we can now snapshot the system. 410 * 411 * Recind nice scheduling while running with the filesystem suspended. 412 */ 413 if (td->td_proc->p_nice > 0) { 414 struct proc *p; 415 416 p = td->td_proc; 417 PROC_LOCK(p); 418 saved_nice = p->p_nice; 419 sched_nice(p, 0); 420 PROC_UNLOCK(p); 421 } 422 /* 423 * Suspend operation on filesystem. 424 */ 425 for (;;) { 426 vn_finished_write(wrtmp); 427 if ((error = vfs_write_suspend(vp->v_mount, 0)) != 0) { 428 vn_start_write(NULL, &wrtmp, V_WAIT); 429 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 430 goto out; 431 } 432 if (mp->mnt_kern_flag & MNTK_SUSPENDED) 433 break; 434 vn_start_write(NULL, &wrtmp, V_WAIT); 435 } 436 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 437 if (ip->i_effnlink == 0) { 438 error = ENOENT; /* Snapshot file unlinked */ 439 goto out1; 440 } 441 if (collectsnapstats) 442 nanotime(&starttime); 443 444 /* The last block might have changed. Copy it again to be sure. */ 445 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)(numblks - 1)), 446 fs->fs_bsize, KERNCRED, BA_CLRBUF, &bp); 447 if (error != 0) 448 goto out1; 449 error = readblock(vp, bp, numblks - 1); 450 bp->b_flags |= B_VALIDSUSPWRT; 451 bawrite(bp); 452 if (error != 0) 453 goto out1; 454 /* 455 * First, copy all the cylinder group maps that have changed. 456 */ 457 for (cg = 0; cg < fs->fs_ncg; cg++) { 458 if ((ACTIVECGNUM(fs, cg) & ACTIVECGOFF(cg)) != 0) 459 continue; 460 redo++; 461 error = UFS_BALLOC(vp, lfragtosize(fs, cgtod(fs, cg)), 462 fs->fs_bsize, KERNCRED, 0, &nbp); 463 if (error) 464 goto out1; 465 error = cgaccount(cg, vp, nbp, 2); 466 bawrite(nbp); 467 if (error) 468 goto out1; 469 } 470 /* 471 * Grab a copy of the superblock and its summary information. 472 * We delay writing it until the suspension is released below. 473 */ 474 copy_fs = malloc((u_long)fs->fs_bsize, M_UFSMNT, M_WAITOK); 475 bcopy(fs, copy_fs, fs->fs_sbsize); 476 if ((fs->fs_flags & (FS_UNCLEAN | FS_NEEDSFSCK)) == 0) 477 copy_fs->fs_clean = 1; 478 size = fs->fs_bsize < SBLOCKSIZE ? fs->fs_bsize : SBLOCKSIZE; 479 if (fs->fs_sbsize < size) 480 bzero(&((char *)copy_fs)[fs->fs_sbsize], 481 size - fs->fs_sbsize); 482 size = blkroundup(fs, fs->fs_cssize); 483 if (fs->fs_contigsumsize > 0) 484 size += fs->fs_ncg * sizeof(int32_t); 485 space = malloc((u_long)size, M_UFSMNT, M_WAITOK); 486 copy_fs->fs_csp = space; 487 bcopy(fs->fs_csp, copy_fs->fs_csp, fs->fs_cssize); 488 space = (char *)space + fs->fs_cssize; 489 loc = howmany(fs->fs_cssize, fs->fs_fsize); 490 i = fs->fs_frag - loc % fs->fs_frag; 491 len = (i == fs->fs_frag) ? 0 : i * fs->fs_fsize; 492 if (len > 0) { 493 if ((error = bread(devvp, fsbtodb(fs, fs->fs_csaddr + loc), 494 len, KERNCRED, &bp)) != 0) { 495 brelse(bp); 496 free(copy_fs->fs_csp, M_UFSMNT); 497 free(copy_fs, M_UFSMNT); 498 copy_fs = NULL; 499 goto out1; 500 } 501 bcopy(bp->b_data, space, (u_int)len); 502 space = (char *)space + len; 503 bp->b_flags |= B_INVAL | B_NOCACHE; 504 brelse(bp); 505 } 506 if (fs->fs_contigsumsize > 0) { 507 copy_fs->fs_maxcluster = lp = space; 508 for (i = 0; i < fs->fs_ncg; i++) 509 *lp++ = fs->fs_contigsumsize; 510 } 511 /* 512 * We must check for active files that have been unlinked 513 * (e.g., with a zero link count). We have to expunge all 514 * trace of these files from the snapshot so that they are 515 * not reclaimed prematurely by fsck or unnecessarily dumped. 516 * We turn off the MNTK_SUSPENDED flag to avoid a panic from 517 * spec_strategy about writing on a suspended filesystem. 518 * Note that we skip unlinked snapshot files as they will 519 * be handled separately below. 520 * 521 * We also calculate the needed size for the snapshot list. 522 */ 523 snaplistsize = fs->fs_ncg + howmany(fs->fs_cssize, fs->fs_bsize) + 524 FSMAXSNAP + 1 /* superblock */ + 1 /* last block */ + 1 /* size */; 525 MNT_ILOCK(mp); 526 mp->mnt_kern_flag &= ~MNTK_SUSPENDED; 527 MNT_IUNLOCK(mp); 528 loop: 529 MNT_VNODE_FOREACH_ALL(xvp, mp, mvp) { 530 if ((xvp->v_usecount == 0 && 531 (xvp->v_iflag & (VI_OWEINACT | VI_DOINGINACT)) == 0) || 532 xvp->v_type == VNON || 533 IS_SNAPSHOT(VTOI(xvp))) { 534 VI_UNLOCK(xvp); 535 continue; 536 } 537 /* 538 * We can skip parent directory vnode because it must have 539 * this snapshot file in it. 540 */ 541 if (xvp == nd.ni_dvp) { 542 VI_UNLOCK(xvp); 543 continue; 544 } 545 vholdl(xvp); 546 if (vn_lock(xvp, LK_EXCLUSIVE | LK_INTERLOCK) != 0) { 547 MNT_VNODE_FOREACH_ALL_ABORT(mp, mvp); 548 vdrop(xvp); 549 goto loop; 550 } 551 VI_LOCK(xvp); 552 if (xvp->v_usecount == 0 && 553 (xvp->v_iflag & (VI_OWEINACT | VI_DOINGINACT)) == 0) { 554 VI_UNLOCK(xvp); 555 VOP_UNLOCK(xvp, 0); 556 vdrop(xvp); 557 continue; 558 } 559 VI_UNLOCK(xvp); 560 if (snapdebug) 561 vn_printf(xvp, "ffs_snapshot: busy vnode "); 562 if (VOP_GETATTR(xvp, &vat, td->td_ucred) == 0 && 563 vat.va_nlink > 0) { 564 VOP_UNLOCK(xvp, 0); 565 vdrop(xvp); 566 continue; 567 } 568 xp = VTOI(xvp); 569 if (ffs_checkfreefile(copy_fs, vp, xp->i_number)) { 570 VOP_UNLOCK(xvp, 0); 571 vdrop(xvp); 572 continue; 573 } 574 /* 575 * If there is a fragment, clear it here. 576 */ 577 blkno = 0; 578 loc = howmany(xp->i_size, fs->fs_bsize) - 1; 579 if (loc < UFS_NDADDR) { 580 len = fragroundup(fs, blkoff(fs, xp->i_size)); 581 if (len != 0 && len < fs->fs_bsize) { 582 ffs_blkfree(ump, copy_fs, vp, 583 DIP(xp, i_db[loc]), len, xp->i_number, 584 xvp->v_type, NULL); 585 blkno = DIP(xp, i_db[loc]); 586 DIP_SET(xp, i_db[loc], 0); 587 } 588 } 589 snaplistsize += 1; 590 if (I_IS_UFS1(xp)) 591 error = expunge_ufs1(vp, xp, copy_fs, fullacct_ufs1, 592 BLK_NOCOPY, 1); 593 else 594 error = expunge_ufs2(vp, xp, copy_fs, fullacct_ufs2, 595 BLK_NOCOPY, 1); 596 if (blkno) 597 DIP_SET(xp, i_db[loc], blkno); 598 if (!error) 599 error = ffs_freefile(ump, copy_fs, vp, xp->i_number, 600 xp->i_mode, NULL); 601 VOP_UNLOCK(xvp, 0); 602 vdrop(xvp); 603 if (error) { 604 free(copy_fs->fs_csp, M_UFSMNT); 605 free(copy_fs, M_UFSMNT); 606 copy_fs = NULL; 607 MNT_VNODE_FOREACH_ALL_ABORT(mp, mvp); 608 goto out1; 609 } 610 } 611 /* 612 * Erase the journal file from the snapshot. 613 */ 614 if (fs->fs_flags & FS_SUJ) { 615 error = softdep_journal_lookup(mp, &xvp); 616 if (error) { 617 free(copy_fs->fs_csp, M_UFSMNT); 618 free(copy_fs, M_UFSMNT); 619 copy_fs = NULL; 620 goto out1; 621 } 622 xp = VTOI(xvp); 623 if (I_IS_UFS1(xp)) 624 error = expunge_ufs1(vp, xp, copy_fs, fullacct_ufs1, 625 BLK_NOCOPY, 0); 626 else 627 error = expunge_ufs2(vp, xp, copy_fs, fullacct_ufs2, 628 BLK_NOCOPY, 0); 629 vput(xvp); 630 } 631 /* 632 * Acquire a lock on the snapdata structure, creating it if necessary. 633 */ 634 sn = ffs_snapdata_acquire(devvp); 635 /* 636 * Change vnode to use shared snapshot lock instead of the original 637 * private lock. 638 */ 639 vp->v_vnlock = &sn->sn_lock; 640 lockmgr(&vp->v_lock, LK_RELEASE, NULL); 641 xp = TAILQ_FIRST(&sn->sn_head); 642 /* 643 * If this is the first snapshot on this filesystem, then we need 644 * to allocate the space for the list of preallocated snapshot blocks. 645 * This list will be refined below, but this preliminary one will 646 * keep us out of deadlock until the full one is ready. 647 */ 648 if (xp == NULL) { 649 snapblklist = malloc(snaplistsize * sizeof(daddr_t), 650 M_UFSMNT, M_WAITOK); 651 blkp = &snapblklist[1]; 652 *blkp++ = lblkno(fs, fs->fs_sblockloc); 653 blkno = fragstoblks(fs, fs->fs_csaddr); 654 for (cg = 0; cg < fs->fs_ncg; cg++) { 655 if (fragstoblks(fs, cgtod(fs, cg) > blkno)) 656 break; 657 *blkp++ = fragstoblks(fs, cgtod(fs, cg)); 658 } 659 len = howmany(fs->fs_cssize, fs->fs_bsize); 660 for (loc = 0; loc < len; loc++) 661 *blkp++ = blkno + loc; 662 for (; cg < fs->fs_ncg; cg++) 663 *blkp++ = fragstoblks(fs, cgtod(fs, cg)); 664 snapblklist[0] = blkp - snapblklist; 665 VI_LOCK(devvp); 666 if (sn->sn_blklist != NULL) 667 panic("ffs_snapshot: non-empty list"); 668 sn->sn_blklist = snapblklist; 669 sn->sn_listsize = blkp - snapblklist; 670 VI_UNLOCK(devvp); 671 } 672 /* 673 * Record snapshot inode. Since this is the newest snapshot, 674 * it must be placed at the end of the list. 675 */ 676 VI_LOCK(devvp); 677 fs->fs_snapinum[snaploc] = ip->i_number; 678 if (ip->i_nextsnap.tqe_prev != 0) 679 panic("ffs_snapshot: %ju already on list", 680 (uintmax_t)ip->i_number); 681 TAILQ_INSERT_TAIL(&sn->sn_head, ip, i_nextsnap); 682 devvp->v_vflag |= VV_COPYONWRITE; 683 VI_UNLOCK(devvp); 684 ASSERT_VOP_LOCKED(vp, "ffs_snapshot vp"); 685 out1: 686 KASSERT((sn != NULL && copy_fs != NULL && error == 0) || 687 (sn == NULL && copy_fs == NULL && error != 0), 688 ("email phk@ and mckusick@")); 689 /* 690 * Resume operation on filesystem. 691 */ 692 vfs_write_resume(vp->v_mount, VR_START_WRITE | VR_NO_SUSPCLR); 693 if (collectsnapstats && starttime.tv_sec > 0) { 694 nanotime(&endtime); 695 timespecsub(&endtime, &starttime); 696 printf("%s: suspended %ld.%03ld sec, redo %ld of %d\n", 697 vp->v_mount->mnt_stat.f_mntonname, (long)endtime.tv_sec, 698 endtime.tv_nsec / 1000000, redo, fs->fs_ncg); 699 } 700 if (copy_fs == NULL) 701 goto out; 702 /* 703 * Copy allocation information from all the snapshots in 704 * this snapshot and then expunge them from its view. 705 */ 706 TAILQ_FOREACH(xp, &sn->sn_head, i_nextsnap) { 707 if (xp == ip) 708 break; 709 if (I_IS_UFS1(xp)) 710 error = expunge_ufs1(vp, xp, fs, snapacct_ufs1, 711 BLK_SNAP, 0); 712 else 713 error = expunge_ufs2(vp, xp, fs, snapacct_ufs2, 714 BLK_SNAP, 0); 715 if (error == 0 && xp->i_effnlink == 0) { 716 error = ffs_freefile(ump, 717 copy_fs, 718 vp, 719 xp->i_number, 720 xp->i_mode, NULL); 721 } 722 if (error) { 723 fs->fs_snapinum[snaploc] = 0; 724 goto done; 725 } 726 } 727 /* 728 * Allocate space for the full list of preallocated snapshot blocks. 729 */ 730 snapblklist = malloc(snaplistsize * sizeof(daddr_t), 731 M_UFSMNT, M_WAITOK); 732 ip->i_snapblklist = &snapblklist[1]; 733 /* 734 * Expunge the blocks used by the snapshots from the set of 735 * blocks marked as used in the snapshot bitmaps. Also, collect 736 * the list of allocated blocks in i_snapblklist. 737 */ 738 if (I_IS_UFS1(ip)) 739 error = expunge_ufs1(vp, ip, copy_fs, mapacct_ufs1, 740 BLK_SNAP, 0); 741 else 742 error = expunge_ufs2(vp, ip, copy_fs, mapacct_ufs2, 743 BLK_SNAP, 0); 744 if (error) { 745 fs->fs_snapinum[snaploc] = 0; 746 free(snapblklist, M_UFSMNT); 747 goto done; 748 } 749 if (snaplistsize < ip->i_snapblklist - snapblklist) 750 panic("ffs_snapshot: list too small"); 751 snaplistsize = ip->i_snapblklist - snapblklist; 752 snapblklist[0] = snaplistsize; 753 ip->i_snapblklist = 0; 754 /* 755 * Write out the list of allocated blocks to the end of the snapshot. 756 */ 757 auio.uio_iov = &aiov; 758 auio.uio_iovcnt = 1; 759 aiov.iov_base = (void *)snapblklist; 760 aiov.iov_len = snaplistsize * sizeof(daddr_t); 761 auio.uio_resid = aiov.iov_len; 762 auio.uio_offset = ip->i_size; 763 auio.uio_segflg = UIO_SYSSPACE; 764 auio.uio_rw = UIO_WRITE; 765 auio.uio_td = td; 766 if ((error = VOP_WRITE(vp, &auio, IO_UNIT, td->td_ucred)) != 0) { 767 fs->fs_snapinum[snaploc] = 0; 768 free(snapblklist, M_UFSMNT); 769 goto done; 770 } 771 /* 772 * Write the superblock and its summary information 773 * to the snapshot. 774 */ 775 blkno = fragstoblks(fs, fs->fs_csaddr); 776 len = howmany(fs->fs_cssize, fs->fs_bsize); 777 space = copy_fs->fs_csp; 778 for (loc = 0; loc < len; loc++) { 779 error = bread(vp, blkno + loc, fs->fs_bsize, KERNCRED, &nbp); 780 if (error) { 781 brelse(nbp); 782 fs->fs_snapinum[snaploc] = 0; 783 free(snapblklist, M_UFSMNT); 784 goto done; 785 } 786 bcopy(space, nbp->b_data, fs->fs_bsize); 787 space = (char *)space + fs->fs_bsize; 788 bawrite(nbp); 789 } 790 error = bread(vp, lblkno(fs, fs->fs_sblockloc), fs->fs_bsize, 791 KERNCRED, &nbp); 792 if (error) { 793 brelse(nbp); 794 } else { 795 loc = blkoff(fs, fs->fs_sblockloc); 796 bcopy((char *)copy_fs, &nbp->b_data[loc], (u_int)fs->fs_sbsize); 797 bawrite(nbp); 798 } 799 /* 800 * As this is the newest list, it is the most inclusive, so 801 * should replace the previous list. 802 */ 803 VI_LOCK(devvp); 804 space = sn->sn_blklist; 805 sn->sn_blklist = snapblklist; 806 sn->sn_listsize = snaplistsize; 807 VI_UNLOCK(devvp); 808 if (space != NULL) 809 free(space, M_UFSMNT); 810 /* 811 * Preallocate all the direct blocks in the snapshot inode so 812 * that we never have to write the inode itself to commit an 813 * update to the contents of the snapshot. Note that once 814 * created, the size of the snapshot will never change, so 815 * there will never be a need to write the inode except to 816 * update the non-integrity-critical time fields and 817 * allocated-block count. 818 */ 819 for (blockno = 0; blockno < UFS_NDADDR; blockno++) { 820 if (DIP(ip, i_db[blockno]) != 0) 821 continue; 822 error = UFS_BALLOC(vp, lblktosize(fs, blockno), 823 fs->fs_bsize, KERNCRED, BA_CLRBUF, &bp); 824 if (error) 825 break; 826 error = readblock(vp, bp, blockno); 827 bawrite(bp); 828 if (error != 0) 829 break; 830 } 831 done: 832 free(copy_fs->fs_csp, M_UFSMNT); 833 free(copy_fs, M_UFSMNT); 834 copy_fs = NULL; 835 out: 836 NDFREE(&nd, NDF_ONLY_PNBUF); 837 if (saved_nice > 0) { 838 struct proc *p; 839 840 p = td->td_proc; 841 PROC_LOCK(p); 842 sched_nice(td->td_proc, saved_nice); 843 PROC_UNLOCK(td->td_proc); 844 } 845 UFS_LOCK(ump); 846 if (fs->fs_active != 0) { 847 free(fs->fs_active, M_DEVBUF); 848 fs->fs_active = 0; 849 } 850 UFS_UNLOCK(ump); 851 MNT_ILOCK(mp); 852 mp->mnt_flag = (mp->mnt_flag & MNT_QUOTA) | (flag & ~MNT_QUOTA); 853 MNT_IUNLOCK(mp); 854 if (error) 855 (void) ffs_truncate(vp, (off_t)0, 0, NOCRED); 856 (void) ffs_syncvnode(vp, MNT_WAIT, 0); 857 if (error) 858 vput(vp); 859 else 860 VOP_UNLOCK(vp, 0); 861 vrele(nd.ni_dvp); 862 vn_finished_write(wrtmp); 863 process_deferred_inactive(mp); 864 return (error); 865 } 866 867 /* 868 * Copy a cylinder group map. All the unallocated blocks are marked 869 * BLK_NOCOPY so that the snapshot knows that it need not copy them 870 * if they are later written. If passno is one, then this is a first 871 * pass, so only setting needs to be done. If passno is 2, then this 872 * is a revision to a previous pass which must be undone as the 873 * replacement pass is done. 874 */ 875 static int 876 cgaccount(cg, vp, nbp, passno) 877 int cg; 878 struct vnode *vp; 879 struct buf *nbp; 880 int passno; 881 { 882 struct buf *bp, *ibp; 883 struct inode *ip; 884 struct cg *cgp; 885 struct fs *fs; 886 ufs2_daddr_t base, numblks; 887 int error, len, loc, indiroff; 888 889 ip = VTOI(vp); 890 fs = ITOFS(ip); 891 if ((error = ffs_getcg(fs, ITODEVVP(ip), cg, &bp, &cgp)) != 0) 892 return (error); 893 UFS_LOCK(ITOUMP(ip)); 894 ACTIVESET(fs, cg); 895 /* 896 * Recomputation of summary information might not have been performed 897 * at mount time. Sync up summary information for current cylinder 898 * group while data is in memory to ensure that result of background 899 * fsck is slightly more consistent. 900 */ 901 fs->fs_cs(fs, cg) = cgp->cg_cs; 902 UFS_UNLOCK(ITOUMP(ip)); 903 bcopy(bp->b_data, nbp->b_data, fs->fs_cgsize); 904 if (fs->fs_cgsize < fs->fs_bsize) 905 bzero(&nbp->b_data[fs->fs_cgsize], 906 fs->fs_bsize - fs->fs_cgsize); 907 cgp = (struct cg *)nbp->b_data; 908 bqrelse(bp); 909 if (passno == 2) 910 nbp->b_flags |= B_VALIDSUSPWRT; 911 numblks = howmany(fs->fs_size, fs->fs_frag); 912 len = howmany(fs->fs_fpg, fs->fs_frag); 913 base = cgbase(fs, cg) / fs->fs_frag; 914 if (base + len >= numblks) 915 len = numblks - base - 1; 916 loc = 0; 917 if (base < UFS_NDADDR) { 918 for ( ; loc < UFS_NDADDR; loc++) { 919 if (ffs_isblock(fs, cg_blksfree(cgp), loc)) 920 DIP_SET(ip, i_db[loc], BLK_NOCOPY); 921 else if (passno == 2 && DIP(ip, i_db[loc])== BLK_NOCOPY) 922 DIP_SET(ip, i_db[loc], 0); 923 else if (passno == 1 && DIP(ip, i_db[loc])== BLK_NOCOPY) 924 panic("ffs_snapshot: lost direct block"); 925 } 926 } 927 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)(base + loc)), 928 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp); 929 if (error) { 930 return (error); 931 } 932 indiroff = (base + loc - UFS_NDADDR) % NINDIR(fs); 933 for ( ; loc < len; loc++, indiroff++) { 934 if (indiroff >= NINDIR(fs)) { 935 if (passno == 2) 936 ibp->b_flags |= B_VALIDSUSPWRT; 937 bawrite(ibp); 938 error = UFS_BALLOC(vp, 939 lblktosize(fs, (off_t)(base + loc)), 940 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp); 941 if (error) { 942 return (error); 943 } 944 indiroff = 0; 945 } 946 if (I_IS_UFS1(ip)) { 947 if (ffs_isblock(fs, cg_blksfree(cgp), loc)) 948 ((ufs1_daddr_t *)(ibp->b_data))[indiroff] = 949 BLK_NOCOPY; 950 else if (passno == 2 && ((ufs1_daddr_t *)(ibp->b_data)) 951 [indiroff] == BLK_NOCOPY) 952 ((ufs1_daddr_t *)(ibp->b_data))[indiroff] = 0; 953 else if (passno == 1 && ((ufs1_daddr_t *)(ibp->b_data)) 954 [indiroff] == BLK_NOCOPY) 955 panic("ffs_snapshot: lost indirect block"); 956 continue; 957 } 958 if (ffs_isblock(fs, cg_blksfree(cgp), loc)) 959 ((ufs2_daddr_t *)(ibp->b_data))[indiroff] = BLK_NOCOPY; 960 else if (passno == 2 && 961 ((ufs2_daddr_t *)(ibp->b_data)) [indiroff] == BLK_NOCOPY) 962 ((ufs2_daddr_t *)(ibp->b_data))[indiroff] = 0; 963 else if (passno == 1 && 964 ((ufs2_daddr_t *)(ibp->b_data)) [indiroff] == BLK_NOCOPY) 965 panic("ffs_snapshot: lost indirect block"); 966 } 967 if (passno == 2) 968 ibp->b_flags |= B_VALIDSUSPWRT; 969 bdwrite(ibp); 970 return (0); 971 } 972 973 /* 974 * Before expunging a snapshot inode, note all the 975 * blocks that it claims with BLK_SNAP so that fsck will 976 * be able to account for those blocks properly and so 977 * that this snapshot knows that it need not copy them 978 * if the other snapshot holding them is freed. This code 979 * is reproduced once each for UFS1 and UFS2. 980 */ 981 static int 982 expunge_ufs1(snapvp, cancelip, fs, acctfunc, expungetype, clearmode) 983 struct vnode *snapvp; 984 struct inode *cancelip; 985 struct fs *fs; 986 int (*acctfunc)(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *, 987 struct fs *, ufs_lbn_t, int); 988 int expungetype; 989 int clearmode; 990 { 991 int i, error, indiroff; 992 ufs_lbn_t lbn, rlbn; 993 ufs2_daddr_t len, blkno, numblks, blksperindir; 994 struct ufs1_dinode *dip; 995 struct thread *td = curthread; 996 struct buf *bp; 997 998 /* 999 * Prepare to expunge the inode. If its inode block has not 1000 * yet been copied, then allocate and fill the copy. 1001 */ 1002 lbn = fragstoblks(fs, ino_to_fsba(fs, cancelip->i_number)); 1003 blkno = 0; 1004 if (lbn < UFS_NDADDR) { 1005 blkno = VTOI(snapvp)->i_din1->di_db[lbn]; 1006 } else { 1007 if (DOINGSOFTDEP(snapvp)) 1008 softdep_prealloc(snapvp, MNT_WAIT); 1009 td->td_pflags |= TDP_COWINPROGRESS; 1010 error = ffs_balloc_ufs1(snapvp, lblktosize(fs, (off_t)lbn), 1011 fs->fs_bsize, KERNCRED, BA_METAONLY, &bp); 1012 td->td_pflags &= ~TDP_COWINPROGRESS; 1013 if (error) 1014 return (error); 1015 indiroff = (lbn - UFS_NDADDR) % NINDIR(fs); 1016 blkno = ((ufs1_daddr_t *)(bp->b_data))[indiroff]; 1017 bqrelse(bp); 1018 } 1019 if (blkno != 0) { 1020 if ((error = bread(snapvp, lbn, fs->fs_bsize, KERNCRED, &bp))) 1021 return (error); 1022 } else { 1023 error = ffs_balloc_ufs1(snapvp, lblktosize(fs, (off_t)lbn), 1024 fs->fs_bsize, KERNCRED, 0, &bp); 1025 if (error) 1026 return (error); 1027 if ((error = readblock(snapvp, bp, lbn)) != 0) 1028 return (error); 1029 } 1030 /* 1031 * Set a snapshot inode to be a zero length file, regular files 1032 * or unlinked snapshots to be completely unallocated. 1033 */ 1034 dip = (struct ufs1_dinode *)bp->b_data + 1035 ino_to_fsbo(fs, cancelip->i_number); 1036 if (clearmode || cancelip->i_effnlink == 0) 1037 dip->di_mode = 0; 1038 dip->di_size = 0; 1039 dip->di_blocks = 0; 1040 dip->di_flags &= ~SF_SNAPSHOT; 1041 bzero(&dip->di_db[0], (UFS_NDADDR + UFS_NIADDR) * sizeof(ufs1_daddr_t)); 1042 bdwrite(bp); 1043 /* 1044 * Now go through and expunge all the blocks in the file 1045 * using the function requested. 1046 */ 1047 numblks = howmany(cancelip->i_size, fs->fs_bsize); 1048 if ((error = (*acctfunc)(snapvp, &cancelip->i_din1->di_db[0], 1049 &cancelip->i_din1->di_db[UFS_NDADDR], fs, 0, expungetype))) 1050 return (error); 1051 if ((error = (*acctfunc)(snapvp, &cancelip->i_din1->di_ib[0], 1052 &cancelip->i_din1->di_ib[UFS_NIADDR], fs, -1, expungetype))) 1053 return (error); 1054 blksperindir = 1; 1055 lbn = -UFS_NDADDR; 1056 len = numblks - UFS_NDADDR; 1057 rlbn = UFS_NDADDR; 1058 for (i = 0; len > 0 && i < UFS_NIADDR; i++) { 1059 error = indiracct_ufs1(snapvp, ITOV(cancelip), i, 1060 cancelip->i_din1->di_ib[i], lbn, rlbn, len, 1061 blksperindir, fs, acctfunc, expungetype); 1062 if (error) 1063 return (error); 1064 blksperindir *= NINDIR(fs); 1065 lbn -= blksperindir + 1; 1066 len -= blksperindir; 1067 rlbn += blksperindir; 1068 } 1069 return (0); 1070 } 1071 1072 /* 1073 * Descend an indirect block chain for vnode cancelvp accounting for all 1074 * its indirect blocks in snapvp. 1075 */ 1076 static int 1077 indiracct_ufs1(snapvp, cancelvp, level, blkno, lbn, rlbn, remblks, 1078 blksperindir, fs, acctfunc, expungetype) 1079 struct vnode *snapvp; 1080 struct vnode *cancelvp; 1081 int level; 1082 ufs1_daddr_t blkno; 1083 ufs_lbn_t lbn; 1084 ufs_lbn_t rlbn; 1085 ufs_lbn_t remblks; 1086 ufs_lbn_t blksperindir; 1087 struct fs *fs; 1088 int (*acctfunc)(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *, 1089 struct fs *, ufs_lbn_t, int); 1090 int expungetype; 1091 { 1092 int error, num, i; 1093 ufs_lbn_t subblksperindir; 1094 struct indir indirs[UFS_NIADDR + 2]; 1095 ufs1_daddr_t last, *bap; 1096 struct buf *bp; 1097 1098 if (blkno == 0) { 1099 if (expungetype == BLK_NOCOPY) 1100 return (0); 1101 panic("indiracct_ufs1: missing indir"); 1102 } 1103 if ((error = ufs_getlbns(cancelvp, rlbn, indirs, &num)) != 0) 1104 return (error); 1105 if (lbn != indirs[num - 1 - level].in_lbn || num < 2) 1106 panic("indiracct_ufs1: botched params"); 1107 /* 1108 * We have to expand bread here since it will deadlock looking 1109 * up the block number for any blocks that are not in the cache. 1110 */ 1111 bp = getblk(cancelvp, lbn, fs->fs_bsize, 0, 0, 0); 1112 bp->b_blkno = fsbtodb(fs, blkno); 1113 if ((bp->b_flags & (B_DONE | B_DELWRI)) == 0 && 1114 (error = readblock(cancelvp, bp, fragstoblks(fs, blkno)))) { 1115 brelse(bp); 1116 return (error); 1117 } 1118 /* 1119 * Account for the block pointers in this indirect block. 1120 */ 1121 last = howmany(remblks, blksperindir); 1122 if (last > NINDIR(fs)) 1123 last = NINDIR(fs); 1124 bap = malloc(fs->fs_bsize, M_DEVBUF, M_WAITOK); 1125 bcopy(bp->b_data, (caddr_t)bap, fs->fs_bsize); 1126 bqrelse(bp); 1127 error = (*acctfunc)(snapvp, &bap[0], &bap[last], fs, 1128 level == 0 ? rlbn : -1, expungetype); 1129 if (error || level == 0) 1130 goto out; 1131 /* 1132 * Account for the block pointers in each of the indirect blocks 1133 * in the levels below us. 1134 */ 1135 subblksperindir = blksperindir / NINDIR(fs); 1136 for (lbn++, level--, i = 0; i < last; i++) { 1137 error = indiracct_ufs1(snapvp, cancelvp, level, bap[i], lbn, 1138 rlbn, remblks, subblksperindir, fs, acctfunc, expungetype); 1139 if (error) 1140 goto out; 1141 rlbn += blksperindir; 1142 lbn -= blksperindir; 1143 remblks -= blksperindir; 1144 } 1145 out: 1146 free(bap, M_DEVBUF); 1147 return (error); 1148 } 1149 1150 /* 1151 * Do both snap accounting and map accounting. 1152 */ 1153 static int 1154 fullacct_ufs1(vp, oldblkp, lastblkp, fs, lblkno, exptype) 1155 struct vnode *vp; 1156 ufs1_daddr_t *oldblkp, *lastblkp; 1157 struct fs *fs; 1158 ufs_lbn_t lblkno; 1159 int exptype; /* BLK_SNAP or BLK_NOCOPY */ 1160 { 1161 int error; 1162 1163 if ((error = snapacct_ufs1(vp, oldblkp, lastblkp, fs, lblkno, exptype))) 1164 return (error); 1165 return (mapacct_ufs1(vp, oldblkp, lastblkp, fs, lblkno, exptype)); 1166 } 1167 1168 /* 1169 * Identify a set of blocks allocated in a snapshot inode. 1170 */ 1171 static int 1172 snapacct_ufs1(vp, oldblkp, lastblkp, fs, lblkno, expungetype) 1173 struct vnode *vp; 1174 ufs1_daddr_t *oldblkp, *lastblkp; 1175 struct fs *fs; 1176 ufs_lbn_t lblkno; 1177 int expungetype; /* BLK_SNAP or BLK_NOCOPY */ 1178 { 1179 struct inode *ip = VTOI(vp); 1180 ufs1_daddr_t blkno, *blkp; 1181 ufs_lbn_t lbn; 1182 struct buf *ibp; 1183 int error; 1184 1185 for ( ; oldblkp < lastblkp; oldblkp++) { 1186 blkno = *oldblkp; 1187 if (blkno == 0 || blkno == BLK_NOCOPY || blkno == BLK_SNAP) 1188 continue; 1189 lbn = fragstoblks(fs, blkno); 1190 if (lbn < UFS_NDADDR) { 1191 blkp = &ip->i_din1->di_db[lbn]; 1192 ip->i_flag |= IN_CHANGE | IN_UPDATE; 1193 } else { 1194 error = ffs_balloc_ufs1(vp, lblktosize(fs, (off_t)lbn), 1195 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp); 1196 if (error) 1197 return (error); 1198 blkp = &((ufs1_daddr_t *)(ibp->b_data)) 1199 [(lbn - UFS_NDADDR) % NINDIR(fs)]; 1200 } 1201 /* 1202 * If we are expunging a snapshot vnode and we 1203 * find a block marked BLK_NOCOPY, then it is 1204 * one that has been allocated to this snapshot after 1205 * we took our current snapshot and can be ignored. 1206 */ 1207 if (expungetype == BLK_SNAP && *blkp == BLK_NOCOPY) { 1208 if (lbn >= UFS_NDADDR) 1209 brelse(ibp); 1210 } else { 1211 if (*blkp != 0) 1212 panic("snapacct_ufs1: bad block"); 1213 *blkp = expungetype; 1214 if (lbn >= UFS_NDADDR) 1215 bdwrite(ibp); 1216 } 1217 } 1218 return (0); 1219 } 1220 1221 /* 1222 * Account for a set of blocks allocated in a snapshot inode. 1223 */ 1224 static int 1225 mapacct_ufs1(vp, oldblkp, lastblkp, fs, lblkno, expungetype) 1226 struct vnode *vp; 1227 ufs1_daddr_t *oldblkp, *lastblkp; 1228 struct fs *fs; 1229 ufs_lbn_t lblkno; 1230 int expungetype; 1231 { 1232 ufs1_daddr_t blkno; 1233 struct inode *ip; 1234 ino_t inum; 1235 int acctit; 1236 1237 ip = VTOI(vp); 1238 inum = ip->i_number; 1239 if (lblkno == -1) 1240 acctit = 0; 1241 else 1242 acctit = 1; 1243 for ( ; oldblkp < lastblkp; oldblkp++, lblkno++) { 1244 blkno = *oldblkp; 1245 if (blkno == 0 || blkno == BLK_NOCOPY) 1246 continue; 1247 if (acctit && expungetype == BLK_SNAP && blkno != BLK_SNAP) 1248 *ip->i_snapblklist++ = lblkno; 1249 if (blkno == BLK_SNAP) 1250 blkno = blkstofrags(fs, lblkno); 1251 ffs_blkfree(ITOUMP(ip), fs, vp, blkno, fs->fs_bsize, inum, 1252 vp->v_type, NULL); 1253 } 1254 return (0); 1255 } 1256 1257 /* 1258 * Before expunging a snapshot inode, note all the 1259 * blocks that it claims with BLK_SNAP so that fsck will 1260 * be able to account for those blocks properly and so 1261 * that this snapshot knows that it need not copy them 1262 * if the other snapshot holding them is freed. This code 1263 * is reproduced once each for UFS1 and UFS2. 1264 */ 1265 static int 1266 expunge_ufs2(snapvp, cancelip, fs, acctfunc, expungetype, clearmode) 1267 struct vnode *snapvp; 1268 struct inode *cancelip; 1269 struct fs *fs; 1270 int (*acctfunc)(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *, 1271 struct fs *, ufs_lbn_t, int); 1272 int expungetype; 1273 int clearmode; 1274 { 1275 int i, error, indiroff; 1276 ufs_lbn_t lbn, rlbn; 1277 ufs2_daddr_t len, blkno, numblks, blksperindir; 1278 struct ufs2_dinode *dip; 1279 struct thread *td = curthread; 1280 struct buf *bp; 1281 1282 /* 1283 * Prepare to expunge the inode. If its inode block has not 1284 * yet been copied, then allocate and fill the copy. 1285 */ 1286 lbn = fragstoblks(fs, ino_to_fsba(fs, cancelip->i_number)); 1287 blkno = 0; 1288 if (lbn < UFS_NDADDR) { 1289 blkno = VTOI(snapvp)->i_din2->di_db[lbn]; 1290 } else { 1291 if (DOINGSOFTDEP(snapvp)) 1292 softdep_prealloc(snapvp, MNT_WAIT); 1293 td->td_pflags |= TDP_COWINPROGRESS; 1294 error = ffs_balloc_ufs2(snapvp, lblktosize(fs, (off_t)lbn), 1295 fs->fs_bsize, KERNCRED, BA_METAONLY, &bp); 1296 td->td_pflags &= ~TDP_COWINPROGRESS; 1297 if (error) 1298 return (error); 1299 indiroff = (lbn - UFS_NDADDR) % NINDIR(fs); 1300 blkno = ((ufs2_daddr_t *)(bp->b_data))[indiroff]; 1301 bqrelse(bp); 1302 } 1303 if (blkno != 0) { 1304 if ((error = bread(snapvp, lbn, fs->fs_bsize, KERNCRED, &bp))) 1305 return (error); 1306 } else { 1307 error = ffs_balloc_ufs2(snapvp, lblktosize(fs, (off_t)lbn), 1308 fs->fs_bsize, KERNCRED, 0, &bp); 1309 if (error) 1310 return (error); 1311 if ((error = readblock(snapvp, bp, lbn)) != 0) 1312 return (error); 1313 } 1314 /* 1315 * Set a snapshot inode to be a zero length file, regular files 1316 * to be completely unallocated. 1317 */ 1318 dip = (struct ufs2_dinode *)bp->b_data + 1319 ino_to_fsbo(fs, cancelip->i_number); 1320 if (clearmode || cancelip->i_effnlink == 0) 1321 dip->di_mode = 0; 1322 dip->di_size = 0; 1323 dip->di_blocks = 0; 1324 dip->di_flags &= ~SF_SNAPSHOT; 1325 bzero(&dip->di_db[0], (UFS_NDADDR + UFS_NIADDR) * sizeof(ufs2_daddr_t)); 1326 bdwrite(bp); 1327 /* 1328 * Now go through and expunge all the blocks in the file 1329 * using the function requested. 1330 */ 1331 numblks = howmany(cancelip->i_size, fs->fs_bsize); 1332 if ((error = (*acctfunc)(snapvp, &cancelip->i_din2->di_db[0], 1333 &cancelip->i_din2->di_db[UFS_NDADDR], fs, 0, expungetype))) 1334 return (error); 1335 if ((error = (*acctfunc)(snapvp, &cancelip->i_din2->di_ib[0], 1336 &cancelip->i_din2->di_ib[UFS_NIADDR], fs, -1, expungetype))) 1337 return (error); 1338 blksperindir = 1; 1339 lbn = -UFS_NDADDR; 1340 len = numblks - UFS_NDADDR; 1341 rlbn = UFS_NDADDR; 1342 for (i = 0; len > 0 && i < UFS_NIADDR; i++) { 1343 error = indiracct_ufs2(snapvp, ITOV(cancelip), i, 1344 cancelip->i_din2->di_ib[i], lbn, rlbn, len, 1345 blksperindir, fs, acctfunc, expungetype); 1346 if (error) 1347 return (error); 1348 blksperindir *= NINDIR(fs); 1349 lbn -= blksperindir + 1; 1350 len -= blksperindir; 1351 rlbn += blksperindir; 1352 } 1353 return (0); 1354 } 1355 1356 /* 1357 * Descend an indirect block chain for vnode cancelvp accounting for all 1358 * its indirect blocks in snapvp. 1359 */ 1360 static int 1361 indiracct_ufs2(snapvp, cancelvp, level, blkno, lbn, rlbn, remblks, 1362 blksperindir, fs, acctfunc, expungetype) 1363 struct vnode *snapvp; 1364 struct vnode *cancelvp; 1365 int level; 1366 ufs2_daddr_t blkno; 1367 ufs_lbn_t lbn; 1368 ufs_lbn_t rlbn; 1369 ufs_lbn_t remblks; 1370 ufs_lbn_t blksperindir; 1371 struct fs *fs; 1372 int (*acctfunc)(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *, 1373 struct fs *, ufs_lbn_t, int); 1374 int expungetype; 1375 { 1376 int error, num, i; 1377 ufs_lbn_t subblksperindir; 1378 struct indir indirs[UFS_NIADDR + 2]; 1379 ufs2_daddr_t last, *bap; 1380 struct buf *bp; 1381 1382 if (blkno == 0) { 1383 if (expungetype == BLK_NOCOPY) 1384 return (0); 1385 panic("indiracct_ufs2: missing indir"); 1386 } 1387 if ((error = ufs_getlbns(cancelvp, rlbn, indirs, &num)) != 0) 1388 return (error); 1389 if (lbn != indirs[num - 1 - level].in_lbn || num < 2) 1390 panic("indiracct_ufs2: botched params"); 1391 /* 1392 * We have to expand bread here since it will deadlock looking 1393 * up the block number for any blocks that are not in the cache. 1394 */ 1395 bp = getblk(cancelvp, lbn, fs->fs_bsize, 0, 0, 0); 1396 bp->b_blkno = fsbtodb(fs, blkno); 1397 if ((bp->b_flags & B_CACHE) == 0 && 1398 (error = readblock(cancelvp, bp, fragstoblks(fs, blkno)))) { 1399 brelse(bp); 1400 return (error); 1401 } 1402 /* 1403 * Account for the block pointers in this indirect block. 1404 */ 1405 last = howmany(remblks, blksperindir); 1406 if (last > NINDIR(fs)) 1407 last = NINDIR(fs); 1408 bap = malloc(fs->fs_bsize, M_DEVBUF, M_WAITOK); 1409 bcopy(bp->b_data, (caddr_t)bap, fs->fs_bsize); 1410 bqrelse(bp); 1411 error = (*acctfunc)(snapvp, &bap[0], &bap[last], fs, 1412 level == 0 ? rlbn : -1, expungetype); 1413 if (error || level == 0) 1414 goto out; 1415 /* 1416 * Account for the block pointers in each of the indirect blocks 1417 * in the levels below us. 1418 */ 1419 subblksperindir = blksperindir / NINDIR(fs); 1420 for (lbn++, level--, i = 0; i < last; i++) { 1421 error = indiracct_ufs2(snapvp, cancelvp, level, bap[i], lbn, 1422 rlbn, remblks, subblksperindir, fs, acctfunc, expungetype); 1423 if (error) 1424 goto out; 1425 rlbn += blksperindir; 1426 lbn -= blksperindir; 1427 remblks -= blksperindir; 1428 } 1429 out: 1430 free(bap, M_DEVBUF); 1431 return (error); 1432 } 1433 1434 /* 1435 * Do both snap accounting and map accounting. 1436 */ 1437 static int 1438 fullacct_ufs2(vp, oldblkp, lastblkp, fs, lblkno, exptype) 1439 struct vnode *vp; 1440 ufs2_daddr_t *oldblkp, *lastblkp; 1441 struct fs *fs; 1442 ufs_lbn_t lblkno; 1443 int exptype; /* BLK_SNAP or BLK_NOCOPY */ 1444 { 1445 int error; 1446 1447 if ((error = snapacct_ufs2(vp, oldblkp, lastblkp, fs, lblkno, exptype))) 1448 return (error); 1449 return (mapacct_ufs2(vp, oldblkp, lastblkp, fs, lblkno, exptype)); 1450 } 1451 1452 /* 1453 * Identify a set of blocks allocated in a snapshot inode. 1454 */ 1455 static int 1456 snapacct_ufs2(vp, oldblkp, lastblkp, fs, lblkno, expungetype) 1457 struct vnode *vp; 1458 ufs2_daddr_t *oldblkp, *lastblkp; 1459 struct fs *fs; 1460 ufs_lbn_t lblkno; 1461 int expungetype; /* BLK_SNAP or BLK_NOCOPY */ 1462 { 1463 struct inode *ip = VTOI(vp); 1464 ufs2_daddr_t blkno, *blkp; 1465 ufs_lbn_t lbn; 1466 struct buf *ibp; 1467 int error; 1468 1469 for ( ; oldblkp < lastblkp; oldblkp++) { 1470 blkno = *oldblkp; 1471 if (blkno == 0 || blkno == BLK_NOCOPY || blkno == BLK_SNAP) 1472 continue; 1473 lbn = fragstoblks(fs, blkno); 1474 if (lbn < UFS_NDADDR) { 1475 blkp = &ip->i_din2->di_db[lbn]; 1476 ip->i_flag |= IN_CHANGE | IN_UPDATE; 1477 } else { 1478 error = ffs_balloc_ufs2(vp, lblktosize(fs, (off_t)lbn), 1479 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp); 1480 if (error) 1481 return (error); 1482 blkp = &((ufs2_daddr_t *)(ibp->b_data)) 1483 [(lbn - UFS_NDADDR) % NINDIR(fs)]; 1484 } 1485 /* 1486 * If we are expunging a snapshot vnode and we 1487 * find a block marked BLK_NOCOPY, then it is 1488 * one that has been allocated to this snapshot after 1489 * we took our current snapshot and can be ignored. 1490 */ 1491 if (expungetype == BLK_SNAP && *blkp == BLK_NOCOPY) { 1492 if (lbn >= UFS_NDADDR) 1493 brelse(ibp); 1494 } else { 1495 if (*blkp != 0) 1496 panic("snapacct_ufs2: bad block"); 1497 *blkp = expungetype; 1498 if (lbn >= UFS_NDADDR) 1499 bdwrite(ibp); 1500 } 1501 } 1502 return (0); 1503 } 1504 1505 /* 1506 * Account for a set of blocks allocated in a snapshot inode. 1507 */ 1508 static int 1509 mapacct_ufs2(vp, oldblkp, lastblkp, fs, lblkno, expungetype) 1510 struct vnode *vp; 1511 ufs2_daddr_t *oldblkp, *lastblkp; 1512 struct fs *fs; 1513 ufs_lbn_t lblkno; 1514 int expungetype; 1515 { 1516 ufs2_daddr_t blkno; 1517 struct inode *ip; 1518 ino_t inum; 1519 int acctit; 1520 1521 ip = VTOI(vp); 1522 inum = ip->i_number; 1523 if (lblkno == -1) 1524 acctit = 0; 1525 else 1526 acctit = 1; 1527 for ( ; oldblkp < lastblkp; oldblkp++, lblkno++) { 1528 blkno = *oldblkp; 1529 if (blkno == 0 || blkno == BLK_NOCOPY) 1530 continue; 1531 if (acctit && expungetype == BLK_SNAP && blkno != BLK_SNAP) 1532 *ip->i_snapblklist++ = lblkno; 1533 if (blkno == BLK_SNAP) 1534 blkno = blkstofrags(fs, lblkno); 1535 ffs_blkfree(ITOUMP(ip), fs, vp, blkno, fs->fs_bsize, inum, 1536 vp->v_type, NULL); 1537 } 1538 return (0); 1539 } 1540 1541 /* 1542 * Decrement extra reference on snapshot when last name is removed. 1543 * It will not be freed until the last open reference goes away. 1544 */ 1545 void 1546 ffs_snapgone(ip) 1547 struct inode *ip; 1548 { 1549 struct inode *xp; 1550 struct fs *fs; 1551 int snaploc; 1552 struct snapdata *sn; 1553 struct ufsmount *ump; 1554 1555 /* 1556 * Find snapshot in incore list. 1557 */ 1558 xp = NULL; 1559 sn = ITODEVVP(ip)->v_rdev->si_snapdata; 1560 if (sn != NULL) 1561 TAILQ_FOREACH(xp, &sn->sn_head, i_nextsnap) 1562 if (xp == ip) 1563 break; 1564 if (xp != NULL) 1565 vrele(ITOV(ip)); 1566 else if (snapdebug) 1567 printf("ffs_snapgone: lost snapshot vnode %ju\n", 1568 (uintmax_t)ip->i_number); 1569 /* 1570 * Delete snapshot inode from superblock. Keep list dense. 1571 */ 1572 ump = ITOUMP(ip); 1573 fs = ump->um_fs; 1574 UFS_LOCK(ump); 1575 for (snaploc = 0; snaploc < FSMAXSNAP; snaploc++) 1576 if (fs->fs_snapinum[snaploc] == ip->i_number) 1577 break; 1578 if (snaploc < FSMAXSNAP) { 1579 for (snaploc++; snaploc < FSMAXSNAP; snaploc++) { 1580 if (fs->fs_snapinum[snaploc] == 0) 1581 break; 1582 fs->fs_snapinum[snaploc - 1] = fs->fs_snapinum[snaploc]; 1583 } 1584 fs->fs_snapinum[snaploc - 1] = 0; 1585 } 1586 UFS_UNLOCK(ump); 1587 } 1588 1589 /* 1590 * Prepare a snapshot file for being removed. 1591 */ 1592 void 1593 ffs_snapremove(vp) 1594 struct vnode *vp; 1595 { 1596 struct inode *ip; 1597 struct vnode *devvp; 1598 struct buf *ibp; 1599 struct fs *fs; 1600 ufs2_daddr_t numblks, blkno, dblk; 1601 int error, i, last, loc; 1602 struct snapdata *sn; 1603 1604 ip = VTOI(vp); 1605 fs = ITOFS(ip); 1606 devvp = ITODEVVP(ip); 1607 /* 1608 * If active, delete from incore list (this snapshot may 1609 * already have been in the process of being deleted, so 1610 * would not have been active). 1611 * 1612 * Clear copy-on-write flag if last snapshot. 1613 */ 1614 VI_LOCK(devvp); 1615 if (ip->i_nextsnap.tqe_prev != 0) { 1616 sn = devvp->v_rdev->si_snapdata; 1617 TAILQ_REMOVE(&sn->sn_head, ip, i_nextsnap); 1618 ip->i_nextsnap.tqe_prev = 0; 1619 VI_UNLOCK(devvp); 1620 lockmgr(&vp->v_lock, LK_EXCLUSIVE, NULL); 1621 for (i = 0; i < sn->sn_lock.lk_recurse; i++) 1622 lockmgr(&vp->v_lock, LK_EXCLUSIVE, NULL); 1623 KASSERT(vp->v_vnlock == &sn->sn_lock, 1624 ("ffs_snapremove: lost lock mutation")); 1625 vp->v_vnlock = &vp->v_lock; 1626 VI_LOCK(devvp); 1627 while (sn->sn_lock.lk_recurse > 0) 1628 lockmgr(&sn->sn_lock, LK_RELEASE, NULL); 1629 lockmgr(&sn->sn_lock, LK_RELEASE, NULL); 1630 try_free_snapdata(devvp); 1631 } else 1632 VI_UNLOCK(devvp); 1633 /* 1634 * Clear all BLK_NOCOPY fields. Pass any block claims to other 1635 * snapshots that want them (see ffs_snapblkfree below). 1636 */ 1637 for (blkno = 1; blkno < UFS_NDADDR; blkno++) { 1638 dblk = DIP(ip, i_db[blkno]); 1639 if (dblk == 0) 1640 continue; 1641 if (dblk == BLK_NOCOPY || dblk == BLK_SNAP) 1642 DIP_SET(ip, i_db[blkno], 0); 1643 else if ((dblk == blkstofrags(fs, blkno) && 1644 ffs_snapblkfree(fs, ITODEVVP(ip), dblk, fs->fs_bsize, 1645 ip->i_number, vp->v_type, NULL))) { 1646 DIP_SET(ip, i_blocks, DIP(ip, i_blocks) - 1647 btodb(fs->fs_bsize)); 1648 DIP_SET(ip, i_db[blkno], 0); 1649 } 1650 } 1651 numblks = howmany(ip->i_size, fs->fs_bsize); 1652 for (blkno = UFS_NDADDR; blkno < numblks; blkno += NINDIR(fs)) { 1653 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)blkno), 1654 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp); 1655 if (error) 1656 continue; 1657 if (fs->fs_size - blkno > NINDIR(fs)) 1658 last = NINDIR(fs); 1659 else 1660 last = fs->fs_size - blkno; 1661 for (loc = 0; loc < last; loc++) { 1662 if (I_IS_UFS1(ip)) { 1663 dblk = ((ufs1_daddr_t *)(ibp->b_data))[loc]; 1664 if (dblk == 0) 1665 continue; 1666 if (dblk == BLK_NOCOPY || dblk == BLK_SNAP) 1667 ((ufs1_daddr_t *)(ibp->b_data))[loc]= 0; 1668 else if ((dblk == blkstofrags(fs, blkno) && 1669 ffs_snapblkfree(fs, ITODEVVP(ip), dblk, 1670 fs->fs_bsize, ip->i_number, vp->v_type, 1671 NULL))) { 1672 ip->i_din1->di_blocks -= 1673 btodb(fs->fs_bsize); 1674 ((ufs1_daddr_t *)(ibp->b_data))[loc]= 0; 1675 } 1676 continue; 1677 } 1678 dblk = ((ufs2_daddr_t *)(ibp->b_data))[loc]; 1679 if (dblk == 0) 1680 continue; 1681 if (dblk == BLK_NOCOPY || dblk == BLK_SNAP) 1682 ((ufs2_daddr_t *)(ibp->b_data))[loc] = 0; 1683 else if ((dblk == blkstofrags(fs, blkno) && 1684 ffs_snapblkfree(fs, ITODEVVP(ip), dblk, 1685 fs->fs_bsize, ip->i_number, vp->v_type, NULL))) { 1686 ip->i_din2->di_blocks -= btodb(fs->fs_bsize); 1687 ((ufs2_daddr_t *)(ibp->b_data))[loc] = 0; 1688 } 1689 } 1690 bawrite(ibp); 1691 } 1692 /* 1693 * Clear snapshot flag and drop reference. 1694 */ 1695 ip->i_flags &= ~SF_SNAPSHOT; 1696 DIP_SET(ip, i_flags, ip->i_flags); 1697 ip->i_flag |= IN_CHANGE | IN_UPDATE; 1698 /* 1699 * The dirtied indirects must be written out before 1700 * softdep_setup_freeblocks() is called. Otherwise indir_trunc() 1701 * may find indirect pointers using the magic BLK_* values. 1702 */ 1703 if (DOINGSOFTDEP(vp)) 1704 ffs_syncvnode(vp, MNT_WAIT, 0); 1705 #ifdef QUOTA 1706 /* 1707 * Reenable disk quotas for ex-snapshot file. 1708 */ 1709 if (!getinoquota(ip)) 1710 (void) chkdq(ip, DIP(ip, i_blocks), KERNCRED, FORCE); 1711 #endif 1712 } 1713 1714 /* 1715 * Notification that a block is being freed. Return zero if the free 1716 * should be allowed to proceed. Return non-zero if the snapshot file 1717 * wants to claim the block. The block will be claimed if it is an 1718 * uncopied part of one of the snapshots. It will be freed if it is 1719 * either a BLK_NOCOPY or has already been copied in all of the snapshots. 1720 * If a fragment is being freed, then all snapshots that care about 1721 * it must make a copy since a snapshot file can only claim full sized 1722 * blocks. Note that if more than one snapshot file maps the block, 1723 * we can pick one at random to claim it. Since none of the snapshots 1724 * can change, we are assurred that they will all see the same unmodified 1725 * image. When deleting a snapshot file (see ffs_snapremove above), we 1726 * must push any of these claimed blocks to one of the other snapshots 1727 * that maps it. These claimed blocks are easily identified as they will 1728 * have a block number equal to their logical block number within the 1729 * snapshot. A copied block can never have this property because they 1730 * must always have been allocated from a BLK_NOCOPY location. 1731 */ 1732 int 1733 ffs_snapblkfree(fs, devvp, bno, size, inum, vtype, wkhd) 1734 struct fs *fs; 1735 struct vnode *devvp; 1736 ufs2_daddr_t bno; 1737 long size; 1738 ino_t inum; 1739 enum vtype vtype; 1740 struct workhead *wkhd; 1741 { 1742 struct buf *ibp, *cbp, *savedcbp = NULL; 1743 struct thread *td = curthread; 1744 struct inode *ip; 1745 struct vnode *vp = NULL; 1746 ufs_lbn_t lbn; 1747 ufs2_daddr_t blkno; 1748 int indiroff = 0, error = 0, claimedblk = 0; 1749 struct snapdata *sn; 1750 1751 lbn = fragstoblks(fs, bno); 1752 retry: 1753 VI_LOCK(devvp); 1754 sn = devvp->v_rdev->si_snapdata; 1755 if (sn == NULL) { 1756 VI_UNLOCK(devvp); 1757 return (0); 1758 } 1759 if (lockmgr(&sn->sn_lock, LK_INTERLOCK | LK_EXCLUSIVE | LK_SLEEPFAIL, 1760 VI_MTX(devvp)) != 0) 1761 goto retry; 1762 TAILQ_FOREACH(ip, &sn->sn_head, i_nextsnap) { 1763 vp = ITOV(ip); 1764 if (DOINGSOFTDEP(vp)) 1765 softdep_prealloc(vp, MNT_WAIT); 1766 /* 1767 * Lookup block being written. 1768 */ 1769 if (lbn < UFS_NDADDR) { 1770 blkno = DIP(ip, i_db[lbn]); 1771 } else { 1772 td->td_pflags |= TDP_COWINPROGRESS; 1773 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)lbn), 1774 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp); 1775 td->td_pflags &= ~TDP_COWINPROGRESS; 1776 if (error) 1777 break; 1778 indiroff = (lbn - UFS_NDADDR) % NINDIR(fs); 1779 if (I_IS_UFS1(ip)) 1780 blkno=((ufs1_daddr_t *)(ibp->b_data))[indiroff]; 1781 else 1782 blkno=((ufs2_daddr_t *)(ibp->b_data))[indiroff]; 1783 } 1784 /* 1785 * Check to see if block needs to be copied. 1786 */ 1787 if (blkno == 0) { 1788 /* 1789 * A block that we map is being freed. If it has not 1790 * been claimed yet, we will claim or copy it (below). 1791 */ 1792 claimedblk = 1; 1793 } else if (blkno == BLK_SNAP) { 1794 /* 1795 * No previous snapshot claimed the block, 1796 * so it will be freed and become a BLK_NOCOPY 1797 * (don't care) for us. 1798 */ 1799 if (claimedblk) 1800 panic("snapblkfree: inconsistent block type"); 1801 if (lbn < UFS_NDADDR) { 1802 DIP_SET(ip, i_db[lbn], BLK_NOCOPY); 1803 ip->i_flag |= IN_CHANGE | IN_UPDATE; 1804 } else if (I_IS_UFS1(ip)) { 1805 ((ufs1_daddr_t *)(ibp->b_data))[indiroff] = 1806 BLK_NOCOPY; 1807 bdwrite(ibp); 1808 } else { 1809 ((ufs2_daddr_t *)(ibp->b_data))[indiroff] = 1810 BLK_NOCOPY; 1811 bdwrite(ibp); 1812 } 1813 continue; 1814 } else /* BLK_NOCOPY or default */ { 1815 /* 1816 * If the snapshot has already copied the block 1817 * (default), or does not care about the block, 1818 * it is not needed. 1819 */ 1820 if (lbn >= UFS_NDADDR) 1821 bqrelse(ibp); 1822 continue; 1823 } 1824 /* 1825 * If this is a full size block, we will just grab it 1826 * and assign it to the snapshot inode. Otherwise we 1827 * will proceed to copy it. See explanation for this 1828 * routine as to why only a single snapshot needs to 1829 * claim this block. 1830 */ 1831 if (size == fs->fs_bsize) { 1832 #ifdef DEBUG 1833 if (snapdebug) 1834 printf("%s %ju lbn %jd from inum %ju\n", 1835 "Grabonremove: snapino", 1836 (uintmax_t)ip->i_number, 1837 (intmax_t)lbn, (uintmax_t)inum); 1838 #endif 1839 /* 1840 * If journaling is tracking this write we must add 1841 * the work to the inode or indirect being written. 1842 */ 1843 if (wkhd != NULL) { 1844 if (lbn < UFS_NDADDR) 1845 softdep_inode_append(ip, 1846 curthread->td_ucred, wkhd); 1847 else 1848 softdep_buf_append(ibp, wkhd); 1849 } 1850 if (lbn < UFS_NDADDR) { 1851 DIP_SET(ip, i_db[lbn], bno); 1852 } else if (I_IS_UFS1(ip)) { 1853 ((ufs1_daddr_t *)(ibp->b_data))[indiroff] = bno; 1854 bdwrite(ibp); 1855 } else { 1856 ((ufs2_daddr_t *)(ibp->b_data))[indiroff] = bno; 1857 bdwrite(ibp); 1858 } 1859 DIP_SET(ip, i_blocks, DIP(ip, i_blocks) + btodb(size)); 1860 ip->i_flag |= IN_CHANGE | IN_UPDATE; 1861 lockmgr(vp->v_vnlock, LK_RELEASE, NULL); 1862 return (1); 1863 } 1864 if (lbn >= UFS_NDADDR) 1865 bqrelse(ibp); 1866 /* 1867 * Allocate the block into which to do the copy. Note that this 1868 * allocation will never require any additional allocations for 1869 * the snapshot inode. 1870 */ 1871 td->td_pflags |= TDP_COWINPROGRESS; 1872 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)lbn), 1873 fs->fs_bsize, KERNCRED, 0, &cbp); 1874 td->td_pflags &= ~TDP_COWINPROGRESS; 1875 if (error) 1876 break; 1877 #ifdef DEBUG 1878 if (snapdebug) 1879 printf("%s%ju lbn %jd %s %ju size %ld to blkno %jd\n", 1880 "Copyonremove: snapino ", (uintmax_t)ip->i_number, 1881 (intmax_t)lbn, "for inum", (uintmax_t)inum, size, 1882 (intmax_t)cbp->b_blkno); 1883 #endif 1884 /* 1885 * If we have already read the old block contents, then 1886 * simply copy them to the new block. Note that we need 1887 * to synchronously write snapshots that have not been 1888 * unlinked, and hence will be visible after a crash, 1889 * to ensure their integrity. At a minimum we ensure the 1890 * integrity of the filesystem metadata, but use the 1891 * dopersistence sysctl-setable flag to decide on the 1892 * persistence needed for file content data. 1893 */ 1894 if (savedcbp != NULL) { 1895 bcopy(savedcbp->b_data, cbp->b_data, fs->fs_bsize); 1896 bawrite(cbp); 1897 if ((vtype == VDIR || dopersistence) && 1898 ip->i_effnlink > 0) 1899 (void) ffs_syncvnode(vp, MNT_WAIT, NO_INO_UPDT); 1900 continue; 1901 } 1902 /* 1903 * Otherwise, read the old block contents into the buffer. 1904 */ 1905 if ((error = readblock(vp, cbp, lbn)) != 0) { 1906 bzero(cbp->b_data, fs->fs_bsize); 1907 bawrite(cbp); 1908 if ((vtype == VDIR || dopersistence) && 1909 ip->i_effnlink > 0) 1910 (void) ffs_syncvnode(vp, MNT_WAIT, NO_INO_UPDT); 1911 break; 1912 } 1913 savedcbp = cbp; 1914 } 1915 /* 1916 * Note that we need to synchronously write snapshots that 1917 * have not been unlinked, and hence will be visible after 1918 * a crash, to ensure their integrity. At a minimum we 1919 * ensure the integrity of the filesystem metadata, but 1920 * use the dopersistence sysctl-setable flag to decide on 1921 * the persistence needed for file content data. 1922 */ 1923 if (savedcbp) { 1924 vp = savedcbp->b_vp; 1925 bawrite(savedcbp); 1926 if ((vtype == VDIR || dopersistence) && 1927 VTOI(vp)->i_effnlink > 0) 1928 (void) ffs_syncvnode(vp, MNT_WAIT, NO_INO_UPDT); 1929 } 1930 /* 1931 * If we have been unable to allocate a block in which to do 1932 * the copy, then return non-zero so that the fragment will 1933 * not be freed. Although space will be lost, the snapshot 1934 * will stay consistent. 1935 */ 1936 if (error != 0 && wkhd != NULL) 1937 softdep_freework(wkhd); 1938 lockmgr(&sn->sn_lock, LK_RELEASE, NULL); 1939 return (error); 1940 } 1941 1942 /* 1943 * Associate snapshot files when mounting. 1944 */ 1945 void 1946 ffs_snapshot_mount(mp) 1947 struct mount *mp; 1948 { 1949 struct ufsmount *ump = VFSTOUFS(mp); 1950 struct vnode *devvp = ump->um_devvp; 1951 struct fs *fs = ump->um_fs; 1952 struct thread *td = curthread; 1953 struct snapdata *sn; 1954 struct vnode *vp; 1955 struct vnode *lastvp; 1956 struct inode *ip; 1957 struct uio auio; 1958 struct iovec aiov; 1959 void *snapblklist; 1960 char *reason; 1961 daddr_t snaplistsize; 1962 int error, snaploc, loc; 1963 1964 /* 1965 * XXX The following needs to be set before ffs_truncate or 1966 * VOP_READ can be called. 1967 */ 1968 mp->mnt_stat.f_iosize = fs->fs_bsize; 1969 /* 1970 * Process each snapshot listed in the superblock. 1971 */ 1972 vp = NULL; 1973 lastvp = NULL; 1974 sn = NULL; 1975 for (snaploc = 0; snaploc < FSMAXSNAP; snaploc++) { 1976 if (fs->fs_snapinum[snaploc] == 0) 1977 break; 1978 if ((error = ffs_vget(mp, fs->fs_snapinum[snaploc], 1979 LK_EXCLUSIVE, &vp)) != 0){ 1980 printf("ffs_snapshot_mount: vget failed %d\n", error); 1981 continue; 1982 } 1983 ip = VTOI(vp); 1984 if (!IS_SNAPSHOT(ip) || ip->i_size == 1985 lblktosize(fs, howmany(fs->fs_size, fs->fs_frag))) { 1986 if (!IS_SNAPSHOT(ip)) { 1987 reason = "non-snapshot"; 1988 } else { 1989 reason = "old format snapshot"; 1990 (void)ffs_truncate(vp, (off_t)0, 0, NOCRED); 1991 (void)ffs_syncvnode(vp, MNT_WAIT, 0); 1992 } 1993 printf("ffs_snapshot_mount: %s inode %d\n", 1994 reason, fs->fs_snapinum[snaploc]); 1995 vput(vp); 1996 vp = NULL; 1997 for (loc = snaploc + 1; loc < FSMAXSNAP; loc++) { 1998 if (fs->fs_snapinum[loc] == 0) 1999 break; 2000 fs->fs_snapinum[loc - 1] = fs->fs_snapinum[loc]; 2001 } 2002 fs->fs_snapinum[loc - 1] = 0; 2003 snaploc--; 2004 continue; 2005 } 2006 /* 2007 * Acquire a lock on the snapdata structure, creating it if 2008 * necessary. 2009 */ 2010 sn = ffs_snapdata_acquire(devvp); 2011 /* 2012 * Change vnode to use shared snapshot lock instead of the 2013 * original private lock. 2014 */ 2015 vp->v_vnlock = &sn->sn_lock; 2016 lockmgr(&vp->v_lock, LK_RELEASE, NULL); 2017 /* 2018 * Link it onto the active snapshot list. 2019 */ 2020 VI_LOCK(devvp); 2021 if (ip->i_nextsnap.tqe_prev != 0) 2022 panic("ffs_snapshot_mount: %ju already on list", 2023 (uintmax_t)ip->i_number); 2024 else 2025 TAILQ_INSERT_TAIL(&sn->sn_head, ip, i_nextsnap); 2026 vp->v_vflag |= VV_SYSTEM; 2027 VI_UNLOCK(devvp); 2028 VOP_UNLOCK(vp, 0); 2029 lastvp = vp; 2030 } 2031 vp = lastvp; 2032 /* 2033 * No usable snapshots found. 2034 */ 2035 if (sn == NULL || vp == NULL) 2036 return; 2037 /* 2038 * Allocate the space for the block hints list. We always want to 2039 * use the list from the newest snapshot. 2040 */ 2041 auio.uio_iov = &aiov; 2042 auio.uio_iovcnt = 1; 2043 aiov.iov_base = (void *)&snaplistsize; 2044 aiov.iov_len = sizeof(snaplistsize); 2045 auio.uio_resid = aiov.iov_len; 2046 auio.uio_offset = 2047 lblktosize(fs, howmany(fs->fs_size, fs->fs_frag)); 2048 auio.uio_segflg = UIO_SYSSPACE; 2049 auio.uio_rw = UIO_READ; 2050 auio.uio_td = td; 2051 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2052 if ((error = VOP_READ(vp, &auio, IO_UNIT, td->td_ucred)) != 0) { 2053 printf("ffs_snapshot_mount: read_1 failed %d\n", error); 2054 VOP_UNLOCK(vp, 0); 2055 return; 2056 } 2057 snapblklist = malloc(snaplistsize * sizeof(daddr_t), 2058 M_UFSMNT, M_WAITOK); 2059 auio.uio_iovcnt = 1; 2060 aiov.iov_base = snapblklist; 2061 aiov.iov_len = snaplistsize * sizeof (daddr_t); 2062 auio.uio_resid = aiov.iov_len; 2063 auio.uio_offset -= sizeof(snaplistsize); 2064 if ((error = VOP_READ(vp, &auio, IO_UNIT, td->td_ucred)) != 0) { 2065 printf("ffs_snapshot_mount: read_2 failed %d\n", error); 2066 VOP_UNLOCK(vp, 0); 2067 free(snapblklist, M_UFSMNT); 2068 return; 2069 } 2070 VOP_UNLOCK(vp, 0); 2071 VI_LOCK(devvp); 2072 ASSERT_VOP_LOCKED(devvp, "ffs_snapshot_mount"); 2073 sn->sn_listsize = snaplistsize; 2074 sn->sn_blklist = (daddr_t *)snapblklist; 2075 devvp->v_vflag |= VV_COPYONWRITE; 2076 VI_UNLOCK(devvp); 2077 } 2078 2079 /* 2080 * Disassociate snapshot files when unmounting. 2081 */ 2082 void 2083 ffs_snapshot_unmount(mp) 2084 struct mount *mp; 2085 { 2086 struct vnode *devvp = VFSTOUFS(mp)->um_devvp; 2087 struct snapdata *sn; 2088 struct inode *xp; 2089 struct vnode *vp; 2090 2091 VI_LOCK(devvp); 2092 sn = devvp->v_rdev->si_snapdata; 2093 while (sn != NULL && (xp = TAILQ_FIRST(&sn->sn_head)) != NULL) { 2094 vp = ITOV(xp); 2095 TAILQ_REMOVE(&sn->sn_head, xp, i_nextsnap); 2096 xp->i_nextsnap.tqe_prev = 0; 2097 lockmgr(&sn->sn_lock, LK_INTERLOCK | LK_EXCLUSIVE, 2098 VI_MTX(devvp)); 2099 lockmgr(&vp->v_lock, LK_EXCLUSIVE, NULL); 2100 KASSERT(vp->v_vnlock == &sn->sn_lock, 2101 ("ffs_snapshot_unmount: lost lock mutation")); 2102 vp->v_vnlock = &vp->v_lock; 2103 lockmgr(&vp->v_lock, LK_RELEASE, NULL); 2104 lockmgr(&sn->sn_lock, LK_RELEASE, NULL); 2105 if (xp->i_effnlink > 0) 2106 vrele(vp); 2107 VI_LOCK(devvp); 2108 sn = devvp->v_rdev->si_snapdata; 2109 } 2110 try_free_snapdata(devvp); 2111 ASSERT_VOP_LOCKED(devvp, "ffs_snapshot_unmount"); 2112 } 2113 2114 /* 2115 * Check the buffer block to be belong to device buffer that shall be 2116 * locked after snaplk. devvp shall be locked on entry, and will be 2117 * leaved locked upon exit. 2118 */ 2119 static int 2120 ffs_bp_snapblk(devvp, bp) 2121 struct vnode *devvp; 2122 struct buf *bp; 2123 { 2124 struct snapdata *sn; 2125 struct fs *fs; 2126 ufs2_daddr_t lbn, *snapblklist; 2127 int lower, upper, mid; 2128 2129 ASSERT_VI_LOCKED(devvp, "ffs_bp_snapblk"); 2130 KASSERT(devvp->v_type == VCHR, ("Not a device %p", devvp)); 2131 sn = devvp->v_rdev->si_snapdata; 2132 if (sn == NULL || TAILQ_FIRST(&sn->sn_head) == NULL) 2133 return (0); 2134 fs = ITOFS(TAILQ_FIRST(&sn->sn_head)); 2135 lbn = fragstoblks(fs, dbtofsb(fs, bp->b_blkno)); 2136 snapblklist = sn->sn_blklist; 2137 upper = sn->sn_listsize - 1; 2138 lower = 1; 2139 while (lower <= upper) { 2140 mid = (lower + upper) / 2; 2141 if (snapblklist[mid] == lbn) 2142 break; 2143 if (snapblklist[mid] < lbn) 2144 lower = mid + 1; 2145 else 2146 upper = mid - 1; 2147 } 2148 if (lower <= upper) 2149 return (1); 2150 return (0); 2151 } 2152 2153 void 2154 ffs_bdflush(bo, bp) 2155 struct bufobj *bo; 2156 struct buf *bp; 2157 { 2158 struct thread *td; 2159 struct vnode *vp, *devvp; 2160 struct buf *nbp; 2161 int bp_bdskip; 2162 2163 if (bo->bo_dirty.bv_cnt <= dirtybufthresh) 2164 return; 2165 2166 td = curthread; 2167 vp = bp->b_vp; 2168 devvp = bo2vnode(bo); 2169 KASSERT(vp == devvp, ("devvp != vp %p %p", bo, bp)); 2170 2171 VI_LOCK(devvp); 2172 bp_bdskip = ffs_bp_snapblk(devvp, bp); 2173 if (bp_bdskip) 2174 bdwriteskip++; 2175 VI_UNLOCK(devvp); 2176 if (bo->bo_dirty.bv_cnt > dirtybufthresh + 10 && !bp_bdskip) { 2177 (void) VOP_FSYNC(vp, MNT_NOWAIT, td); 2178 altbufferflushes++; 2179 } else { 2180 BO_LOCK(bo); 2181 /* 2182 * Try to find a buffer to flush. 2183 */ 2184 TAILQ_FOREACH(nbp, &bo->bo_dirty.bv_hd, b_bobufs) { 2185 if ((nbp->b_vflags & BV_BKGRDINPROG) || 2186 BUF_LOCK(nbp, 2187 LK_EXCLUSIVE | LK_NOWAIT, NULL)) 2188 continue; 2189 if (bp == nbp) 2190 panic("bdwrite: found ourselves"); 2191 BO_UNLOCK(bo); 2192 /* 2193 * Don't countdeps with the bo lock 2194 * held. 2195 */ 2196 if (buf_countdeps(nbp, 0)) { 2197 BO_LOCK(bo); 2198 BUF_UNLOCK(nbp); 2199 continue; 2200 } 2201 if (bp_bdskip) { 2202 VI_LOCK(devvp); 2203 if (!ffs_bp_snapblk(vp, nbp)) { 2204 VI_UNLOCK(devvp); 2205 BO_LOCK(bo); 2206 BUF_UNLOCK(nbp); 2207 continue; 2208 } 2209 VI_UNLOCK(devvp); 2210 } 2211 if (nbp->b_flags & B_CLUSTEROK) { 2212 vfs_bio_awrite(nbp); 2213 } else { 2214 bremfree(nbp); 2215 bawrite(nbp); 2216 } 2217 dirtybufferflushes++; 2218 break; 2219 } 2220 if (nbp == NULL) 2221 BO_UNLOCK(bo); 2222 } 2223 } 2224 2225 /* 2226 * Check for need to copy block that is about to be written, 2227 * copying the block if necessary. 2228 */ 2229 int 2230 ffs_copyonwrite(devvp, bp) 2231 struct vnode *devvp; 2232 struct buf *bp; 2233 { 2234 struct snapdata *sn; 2235 struct buf *ibp, *cbp, *savedcbp = NULL; 2236 struct thread *td = curthread; 2237 struct fs *fs; 2238 struct inode *ip; 2239 struct vnode *vp = NULL; 2240 ufs2_daddr_t lbn, blkno, *snapblklist; 2241 int lower, upper, mid, indiroff, error = 0; 2242 int launched_async_io, prev_norunningbuf; 2243 long saved_runningbufspace; 2244 2245 if (devvp != bp->b_vp && IS_SNAPSHOT(VTOI(bp->b_vp))) 2246 return (0); /* Update on a snapshot file */ 2247 if (td->td_pflags & TDP_COWINPROGRESS) 2248 panic("ffs_copyonwrite: recursive call"); 2249 /* 2250 * First check to see if it is in the preallocated list. 2251 * By doing this check we avoid several potential deadlocks. 2252 */ 2253 VI_LOCK(devvp); 2254 sn = devvp->v_rdev->si_snapdata; 2255 if (sn == NULL || 2256 TAILQ_EMPTY(&sn->sn_head)) { 2257 VI_UNLOCK(devvp); 2258 return (0); /* No snapshot */ 2259 } 2260 ip = TAILQ_FIRST(&sn->sn_head); 2261 fs = ITOFS(ip); 2262 lbn = fragstoblks(fs, dbtofsb(fs, bp->b_blkno)); 2263 snapblklist = sn->sn_blklist; 2264 upper = sn->sn_listsize - 1; 2265 lower = 1; 2266 while (lower <= upper) { 2267 mid = (lower + upper) / 2; 2268 if (snapblklist[mid] == lbn) 2269 break; 2270 if (snapblklist[mid] < lbn) 2271 lower = mid + 1; 2272 else 2273 upper = mid - 1; 2274 } 2275 if (lower <= upper) { 2276 VI_UNLOCK(devvp); 2277 return (0); 2278 } 2279 launched_async_io = 0; 2280 prev_norunningbuf = td->td_pflags & TDP_NORUNNINGBUF; 2281 /* 2282 * Since I/O on bp isn't yet in progress and it may be blocked 2283 * for a long time waiting on snaplk, back it out of 2284 * runningbufspace, possibly waking other threads waiting for space. 2285 */ 2286 saved_runningbufspace = bp->b_runningbufspace; 2287 if (saved_runningbufspace != 0) 2288 runningbufwakeup(bp); 2289 /* 2290 * Not in the precomputed list, so check the snapshots. 2291 */ 2292 while (lockmgr(&sn->sn_lock, LK_INTERLOCK | LK_EXCLUSIVE | LK_SLEEPFAIL, 2293 VI_MTX(devvp)) != 0) { 2294 VI_LOCK(devvp); 2295 sn = devvp->v_rdev->si_snapdata; 2296 if (sn == NULL || 2297 TAILQ_EMPTY(&sn->sn_head)) { 2298 VI_UNLOCK(devvp); 2299 if (saved_runningbufspace != 0) { 2300 bp->b_runningbufspace = saved_runningbufspace; 2301 atomic_add_long(&runningbufspace, 2302 bp->b_runningbufspace); 2303 } 2304 return (0); /* Snapshot gone */ 2305 } 2306 } 2307 TAILQ_FOREACH(ip, &sn->sn_head, i_nextsnap) { 2308 vp = ITOV(ip); 2309 if (DOINGSOFTDEP(vp)) 2310 softdep_prealloc(vp, MNT_WAIT); 2311 /* 2312 * We ensure that everything of our own that needs to be 2313 * copied will be done at the time that ffs_snapshot is 2314 * called. Thus we can skip the check here which can 2315 * deadlock in doing the lookup in UFS_BALLOC. 2316 */ 2317 if (bp->b_vp == vp) 2318 continue; 2319 /* 2320 * Check to see if block needs to be copied. We do not have 2321 * to hold the snapshot lock while doing this lookup as it 2322 * will never require any additional allocations for the 2323 * snapshot inode. 2324 */ 2325 if (lbn < UFS_NDADDR) { 2326 blkno = DIP(ip, i_db[lbn]); 2327 } else { 2328 td->td_pflags |= TDP_COWINPROGRESS | TDP_NORUNNINGBUF; 2329 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)lbn), 2330 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp); 2331 td->td_pflags &= ~TDP_COWINPROGRESS; 2332 if (error) 2333 break; 2334 indiroff = (lbn - UFS_NDADDR) % NINDIR(fs); 2335 if (I_IS_UFS1(ip)) 2336 blkno=((ufs1_daddr_t *)(ibp->b_data))[indiroff]; 2337 else 2338 blkno=((ufs2_daddr_t *)(ibp->b_data))[indiroff]; 2339 bqrelse(ibp); 2340 } 2341 #ifdef INVARIANTS 2342 if (blkno == BLK_SNAP && bp->b_lblkno >= 0) 2343 panic("ffs_copyonwrite: bad copy block"); 2344 #endif 2345 if (blkno != 0) 2346 continue; 2347 /* 2348 * Allocate the block into which to do the copy. Since 2349 * multiple processes may all try to copy the same block, 2350 * we have to recheck our need to do a copy if we sleep 2351 * waiting for the lock. 2352 * 2353 * Because all snapshots on a filesystem share a single 2354 * lock, we ensure that we will never be in competition 2355 * with another process to allocate a block. 2356 */ 2357 td->td_pflags |= TDP_COWINPROGRESS | TDP_NORUNNINGBUF; 2358 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)lbn), 2359 fs->fs_bsize, KERNCRED, 0, &cbp); 2360 td->td_pflags &= ~TDP_COWINPROGRESS; 2361 if (error) 2362 break; 2363 #ifdef DEBUG 2364 if (snapdebug) { 2365 printf("Copyonwrite: snapino %ju lbn %jd for ", 2366 (uintmax_t)ip->i_number, (intmax_t)lbn); 2367 if (bp->b_vp == devvp) 2368 printf("fs metadata"); 2369 else 2370 printf("inum %ju", 2371 (uintmax_t)VTOI(bp->b_vp)->i_number); 2372 printf(" lblkno %jd to blkno %jd\n", 2373 (intmax_t)bp->b_lblkno, (intmax_t)cbp->b_blkno); 2374 } 2375 #endif 2376 /* 2377 * If we have already read the old block contents, then 2378 * simply copy them to the new block. Note that we need 2379 * to synchronously write snapshots that have not been 2380 * unlinked, and hence will be visible after a crash, 2381 * to ensure their integrity. At a minimum we ensure the 2382 * integrity of the filesystem metadata, but use the 2383 * dopersistence sysctl-setable flag to decide on the 2384 * persistence needed for file content data. 2385 */ 2386 if (savedcbp != NULL) { 2387 bcopy(savedcbp->b_data, cbp->b_data, fs->fs_bsize); 2388 bawrite(cbp); 2389 if ((devvp == bp->b_vp || bp->b_vp->v_type == VDIR || 2390 dopersistence) && ip->i_effnlink > 0) 2391 (void) ffs_syncvnode(vp, MNT_WAIT, NO_INO_UPDT); 2392 else 2393 launched_async_io = 1; 2394 continue; 2395 } 2396 /* 2397 * Otherwise, read the old block contents into the buffer. 2398 */ 2399 if ((error = readblock(vp, cbp, lbn)) != 0) { 2400 bzero(cbp->b_data, fs->fs_bsize); 2401 bawrite(cbp); 2402 if ((devvp == bp->b_vp || bp->b_vp->v_type == VDIR || 2403 dopersistence) && ip->i_effnlink > 0) 2404 (void) ffs_syncvnode(vp, MNT_WAIT, NO_INO_UPDT); 2405 else 2406 launched_async_io = 1; 2407 break; 2408 } 2409 savedcbp = cbp; 2410 } 2411 /* 2412 * Note that we need to synchronously write snapshots that 2413 * have not been unlinked, and hence will be visible after 2414 * a crash, to ensure their integrity. At a minimum we 2415 * ensure the integrity of the filesystem metadata, but 2416 * use the dopersistence sysctl-setable flag to decide on 2417 * the persistence needed for file content data. 2418 */ 2419 if (savedcbp) { 2420 vp = savedcbp->b_vp; 2421 bawrite(savedcbp); 2422 if ((devvp == bp->b_vp || bp->b_vp->v_type == VDIR || 2423 dopersistence) && VTOI(vp)->i_effnlink > 0) 2424 (void) ffs_syncvnode(vp, MNT_WAIT, NO_INO_UPDT); 2425 else 2426 launched_async_io = 1; 2427 } 2428 lockmgr(vp->v_vnlock, LK_RELEASE, NULL); 2429 td->td_pflags = (td->td_pflags & ~TDP_NORUNNINGBUF) | 2430 prev_norunningbuf; 2431 if (launched_async_io && (td->td_pflags & TDP_NORUNNINGBUF) == 0) 2432 waitrunningbufspace(); 2433 /* 2434 * I/O on bp will now be started, so count it in runningbufspace. 2435 */ 2436 if (saved_runningbufspace != 0) { 2437 bp->b_runningbufspace = saved_runningbufspace; 2438 atomic_add_long(&runningbufspace, bp->b_runningbufspace); 2439 } 2440 return (error); 2441 } 2442 2443 /* 2444 * sync snapshots to force freework records waiting on snapshots to claim 2445 * blocks to free. 2446 */ 2447 void 2448 ffs_sync_snap(mp, waitfor) 2449 struct mount *mp; 2450 int waitfor; 2451 { 2452 struct snapdata *sn; 2453 struct vnode *devvp; 2454 struct vnode *vp; 2455 struct inode *ip; 2456 2457 devvp = VFSTOUFS(mp)->um_devvp; 2458 if ((devvp->v_vflag & VV_COPYONWRITE) == 0) 2459 return; 2460 for (;;) { 2461 VI_LOCK(devvp); 2462 sn = devvp->v_rdev->si_snapdata; 2463 if (sn == NULL) { 2464 VI_UNLOCK(devvp); 2465 return; 2466 } 2467 if (lockmgr(&sn->sn_lock, 2468 LK_INTERLOCK | LK_EXCLUSIVE | LK_SLEEPFAIL, 2469 VI_MTX(devvp)) == 0) 2470 break; 2471 } 2472 TAILQ_FOREACH(ip, &sn->sn_head, i_nextsnap) { 2473 vp = ITOV(ip); 2474 ffs_syncvnode(vp, waitfor, NO_INO_UPDT); 2475 } 2476 lockmgr(&sn->sn_lock, LK_RELEASE, NULL); 2477 } 2478 2479 /* 2480 * Read the specified block into the given buffer. 2481 * Much of this boiler-plate comes from bwrite(). 2482 */ 2483 static int 2484 readblock(vp, bp, lbn) 2485 struct vnode *vp; 2486 struct buf *bp; 2487 ufs2_daddr_t lbn; 2488 { 2489 struct inode *ip = VTOI(vp); 2490 struct bio *bip; 2491 struct fs *fs; 2492 2493 ip = VTOI(vp); 2494 fs = ITOFS(ip); 2495 2496 bip = g_alloc_bio(); 2497 bip->bio_cmd = BIO_READ; 2498 bip->bio_offset = dbtob(fsbtodb(fs, blkstofrags(fs, lbn))); 2499 bip->bio_data = bp->b_data; 2500 bip->bio_length = bp->b_bcount; 2501 bip->bio_done = NULL; 2502 2503 g_io_request(bip, ITODEVVP(ip)->v_bufobj.bo_private); 2504 bp->b_error = biowait(bip, "snaprdb"); 2505 g_destroy_bio(bip); 2506 return (bp->b_error); 2507 } 2508 2509 #endif 2510 2511 /* 2512 * Process file deletes that were deferred by ufs_inactive() due to 2513 * the file system being suspended. Transfer IN_LAZYACCESS into 2514 * IN_MODIFIED for vnodes that were accessed during suspension. 2515 */ 2516 void 2517 process_deferred_inactive(struct mount *mp) 2518 { 2519 struct vnode *vp, *mvp; 2520 struct inode *ip; 2521 struct thread *td; 2522 int error; 2523 2524 td = curthread; 2525 (void) vn_start_secondary_write(NULL, &mp, V_WAIT); 2526 loop: 2527 MNT_VNODE_FOREACH_ALL(vp, mp, mvp) { 2528 /* 2529 * IN_LAZYACCESS is checked here without holding any 2530 * vnode lock, but this flag is set only while holding 2531 * vnode interlock. 2532 */ 2533 if (vp->v_type == VNON || 2534 ((VTOI(vp)->i_flag & IN_LAZYACCESS) == 0 && 2535 ((vp->v_iflag & VI_OWEINACT) == 0 || vp->v_usecount > 0))) { 2536 VI_UNLOCK(vp); 2537 continue; 2538 } 2539 vholdl(vp); 2540 error = vn_lock(vp, LK_EXCLUSIVE | LK_INTERLOCK); 2541 if (error != 0) { 2542 vdrop(vp); 2543 if (error == ENOENT) 2544 continue; /* vnode recycled */ 2545 MNT_VNODE_FOREACH_ALL_ABORT(mp, mvp); 2546 goto loop; 2547 } 2548 ip = VTOI(vp); 2549 if ((ip->i_flag & IN_LAZYACCESS) != 0) { 2550 ip->i_flag &= ~IN_LAZYACCESS; 2551 ip->i_flag |= IN_MODIFIED; 2552 } 2553 VI_LOCK(vp); 2554 if ((vp->v_iflag & VI_OWEINACT) == 0 || vp->v_usecount > 0) { 2555 VI_UNLOCK(vp); 2556 VOP_UNLOCK(vp, 0); 2557 vdrop(vp); 2558 continue; 2559 } 2560 vinactive(vp, td); 2561 VNASSERT((vp->v_iflag & VI_OWEINACT) == 0, vp, 2562 ("process_deferred_inactive: got VI_OWEINACT")); 2563 VI_UNLOCK(vp); 2564 VOP_UNLOCK(vp, 0); 2565 vdrop(vp); 2566 } 2567 vn_finished_secondary_write(mp); 2568 } 2569 2570 #ifndef NO_FFS_SNAPSHOT 2571 2572 static struct snapdata * 2573 ffs_snapdata_alloc(void) 2574 { 2575 struct snapdata *sn; 2576 2577 /* 2578 * Fetch a snapdata from the free list if there is one available. 2579 */ 2580 mtx_lock(&snapfree_lock); 2581 sn = LIST_FIRST(&snapfree); 2582 if (sn != NULL) 2583 LIST_REMOVE(sn, sn_link); 2584 mtx_unlock(&snapfree_lock); 2585 if (sn != NULL) 2586 return (sn); 2587 /* 2588 * If there were no free snapdatas allocate one. 2589 */ 2590 sn = malloc(sizeof *sn, M_UFSMNT, M_WAITOK | M_ZERO); 2591 TAILQ_INIT(&sn->sn_head); 2592 lockinit(&sn->sn_lock, PVFS, "snaplk", VLKTIMEOUT, 2593 LK_CANRECURSE | LK_NOSHARE); 2594 return (sn); 2595 } 2596 2597 /* 2598 * The snapdata is never freed because we can not be certain that 2599 * there are no threads sleeping on the snap lock. Persisting 2600 * them permanently avoids costly synchronization in ffs_lock(). 2601 */ 2602 static void 2603 ffs_snapdata_free(struct snapdata *sn) 2604 { 2605 mtx_lock(&snapfree_lock); 2606 LIST_INSERT_HEAD(&snapfree, sn, sn_link); 2607 mtx_unlock(&snapfree_lock); 2608 } 2609 2610 /* Try to free snapdata associated with devvp */ 2611 static void 2612 try_free_snapdata(struct vnode *devvp) 2613 { 2614 struct snapdata *sn; 2615 ufs2_daddr_t *snapblklist; 2616 2617 ASSERT_VI_LOCKED(devvp, "try_free_snapdata"); 2618 sn = devvp->v_rdev->si_snapdata; 2619 2620 if (sn == NULL || TAILQ_FIRST(&sn->sn_head) != NULL || 2621 (devvp->v_vflag & VV_COPYONWRITE) == 0) { 2622 VI_UNLOCK(devvp); 2623 return; 2624 } 2625 2626 devvp->v_rdev->si_snapdata = NULL; 2627 devvp->v_vflag &= ~VV_COPYONWRITE; 2628 lockmgr(&sn->sn_lock, LK_DRAIN|LK_INTERLOCK, VI_MTX(devvp)); 2629 snapblklist = sn->sn_blklist; 2630 sn->sn_blklist = NULL; 2631 sn->sn_listsize = 0; 2632 lockmgr(&sn->sn_lock, LK_RELEASE, NULL); 2633 if (snapblklist != NULL) 2634 free(snapblklist, M_UFSMNT); 2635 ffs_snapdata_free(sn); 2636 } 2637 2638 static struct snapdata * 2639 ffs_snapdata_acquire(struct vnode *devvp) 2640 { 2641 struct snapdata *nsn, *sn; 2642 int error; 2643 2644 /* 2645 * Allocate a free snapdata. This is done before acquiring the 2646 * devvp lock to avoid allocation while the devvp interlock is 2647 * held. 2648 */ 2649 nsn = ffs_snapdata_alloc(); 2650 2651 for (;;) { 2652 VI_LOCK(devvp); 2653 sn = devvp->v_rdev->si_snapdata; 2654 if (sn == NULL) { 2655 /* 2656 * This is the first snapshot on this 2657 * filesystem and we use our pre-allocated 2658 * snapdata. Publish sn with the sn_lock 2659 * owned by us, to avoid the race. 2660 */ 2661 error = lockmgr(&nsn->sn_lock, LK_EXCLUSIVE | 2662 LK_NOWAIT, NULL); 2663 if (error != 0) 2664 panic("leaked sn, lockmgr error %d", error); 2665 sn = devvp->v_rdev->si_snapdata = nsn; 2666 VI_UNLOCK(devvp); 2667 nsn = NULL; 2668 break; 2669 } 2670 2671 /* 2672 * There is a snapshots which already exists on this 2673 * filesystem, grab a reference to the common lock. 2674 */ 2675 error = lockmgr(&sn->sn_lock, LK_INTERLOCK | 2676 LK_EXCLUSIVE | LK_SLEEPFAIL, VI_MTX(devvp)); 2677 if (error == 0) 2678 break; 2679 } 2680 2681 /* 2682 * Free any unused snapdata. 2683 */ 2684 if (nsn != NULL) 2685 ffs_snapdata_free(nsn); 2686 2687 return (sn); 2688 } 2689 2690 #endif 2691