1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 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 38 #include <sys/cdefs.h> 39 __FBSDID("$FreeBSD$"); 40 41 #include "opt_quota.h" 42 43 #include <sys/param.h> 44 #include <sys/kernel.h> 45 #include <sys/systm.h> 46 #include <sys/conf.h> 47 #include <sys/bio.h> 48 #include <sys/buf.h> 49 #include <sys/fcntl.h> 50 #include <sys/proc.h> 51 #include <sys/namei.h> 52 #include <sys/sched.h> 53 #include <sys/stat.h> 54 #include <sys/malloc.h> 55 #include <sys/mount.h> 56 #include <sys/resource.h> 57 #include <sys/resourcevar.h> 58 #include <sys/rwlock.h> 59 #include <sys/vnode.h> 60 61 #include <geom/geom.h> 62 63 #include <ufs/ufs/extattr.h> 64 #include <ufs/ufs/quota.h> 65 #include <ufs/ufs/ufsmount.h> 66 #include <ufs/ufs/inode.h> 67 #include <ufs/ufs/ufs_extern.h> 68 69 #include <ufs/ffs/fs.h> 70 #include <ufs/ffs/ffs_extern.h> 71 72 #define KERNCRED thread0.td_ucred 73 #define DEBUG 1 74 75 #include "opt_ffs.h" 76 77 #ifdef NO_FFS_SNAPSHOT 78 int 79 ffs_snapshot(mp, snapfile) 80 struct mount *mp; 81 char *snapfile; 82 { 83 return (EINVAL); 84 } 85 86 int 87 ffs_snapblkfree(fs, devvp, bno, size, inum, vtype, wkhd) 88 struct fs *fs; 89 struct vnode *devvp; 90 ufs2_daddr_t bno; 91 long size; 92 ino_t inum; 93 enum vtype vtype; 94 struct workhead *wkhd; 95 { 96 return (EINVAL); 97 } 98 99 void 100 ffs_snapremove(vp) 101 struct vnode *vp; 102 { 103 } 104 105 void 106 ffs_snapshot_mount(mp) 107 struct mount *mp; 108 { 109 } 110 111 void 112 ffs_snapshot_unmount(mp) 113 struct mount *mp; 114 { 115 } 116 117 void 118 ffs_snapgone(ip) 119 struct inode *ip; 120 { 121 } 122 123 int 124 ffs_copyonwrite(devvp, bp) 125 struct vnode *devvp; 126 struct buf *bp; 127 { 128 return (EINVAL); 129 } 130 131 void 132 ffs_sync_snap(mp, waitfor) 133 struct mount *mp; 134 int waitfor; 135 { 136 } 137 138 #else 139 FEATURE(ffs_snapshot, "FFS snapshot support"); 140 141 LIST_HEAD(, snapdata) snapfree; 142 static struct mtx snapfree_lock; 143 MTX_SYSINIT(ffs_snapfree, &snapfree_lock, "snapdata free list", MTX_DEF); 144 145 static int cgaccount(int, struct vnode *, struct buf *, int); 146 static int expunge_ufs1(struct vnode *, struct inode *, struct fs *, 147 int (*)(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *, struct fs *, 148 ufs_lbn_t, int), int, int); 149 static int indiracct_ufs1(struct vnode *, struct vnode *, int, 150 ufs1_daddr_t, ufs_lbn_t, ufs_lbn_t, ufs_lbn_t, ufs_lbn_t, struct fs *, 151 int (*)(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *, struct fs *, 152 ufs_lbn_t, int), int); 153 static int fullacct_ufs1(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *, 154 struct fs *, ufs_lbn_t, int); 155 static int snapacct_ufs1(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *, 156 struct fs *, ufs_lbn_t, int); 157 static int mapacct_ufs1(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *, 158 struct fs *, ufs_lbn_t, int); 159 static int expunge_ufs2(struct vnode *, struct inode *, struct fs *, 160 int (*)(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *, struct fs *, 161 ufs_lbn_t, int), int, int); 162 static int indiracct_ufs2(struct vnode *, struct vnode *, int, 163 ufs2_daddr_t, ufs_lbn_t, ufs_lbn_t, ufs_lbn_t, ufs_lbn_t, struct fs *, 164 int (*)(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *, struct fs *, 165 ufs_lbn_t, int), int); 166 static int fullacct_ufs2(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *, 167 struct fs *, ufs_lbn_t, int); 168 static int snapacct_ufs2(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *, 169 struct fs *, ufs_lbn_t, int); 170 static int mapacct_ufs2(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *, 171 struct fs *, ufs_lbn_t, int); 172 static int readblock(struct vnode *vp, struct buf *, ufs2_daddr_t); 173 static void try_free_snapdata(struct vnode *devvp); 174 static struct snapdata *ffs_snapdata_acquire(struct vnode *devvp); 175 static int ffs_bp_snapblk(struct vnode *, struct buf *); 176 177 /* 178 * To ensure the consistency of snapshots across crashes, we must 179 * synchronously write out copied blocks before allowing the 180 * originals to be modified. Because of the rather severe speed 181 * penalty that this imposes, the code normally only ensures 182 * persistence for the filesystem metadata contained within a 183 * snapshot. Setting the following flag allows this crash 184 * persistence to be enabled for file contents. 185 */ 186 int dopersistence = 0; 187 188 #ifdef DEBUG 189 #include <sys/sysctl.h> 190 SYSCTL_INT(_debug, OID_AUTO, dopersistence, CTLFLAG_RW, &dopersistence, 0, ""); 191 static int snapdebug = 0; 192 SYSCTL_INT(_debug, OID_AUTO, snapdebug, CTLFLAG_RW, &snapdebug, 0, ""); 193 int collectsnapstats = 0; 194 SYSCTL_INT(_debug, OID_AUTO, collectsnapstats, CTLFLAG_RW, &collectsnapstats, 195 0, ""); 196 #endif /* DEBUG */ 197 198 /* 199 * Create a snapshot file and initialize it for the filesystem. 200 */ 201 int 202 ffs_snapshot(mp, snapfile) 203 struct mount *mp; 204 char *snapfile; 205 { 206 ufs2_daddr_t numblks, blkno, *blkp, *snapblklist; 207 int error, cg, snaploc; 208 int i, size, len, loc; 209 ufs2_daddr_t blockno; 210 uint64_t flag; 211 struct timespec starttime = {0, 0}, endtime; 212 char saved_nice = 0; 213 long redo = 0, snaplistsize = 0; 214 int32_t *lp; 215 void *space; 216 struct fs *copy_fs = NULL, *fs; 217 struct thread *td = curthread; 218 struct inode *ip, *xp; 219 struct buf *bp, *nbp, *ibp; 220 struct nameidata nd; 221 struct mount *wrtmp; 222 struct vattr vat; 223 struct vnode *vp, *xvp, *mvp, *devvp; 224 struct uio auio; 225 struct iovec aiov; 226 struct snapdata *sn; 227 struct ufsmount *ump; 228 229 ump = VFSTOUFS(mp); 230 fs = ump->um_fs; 231 sn = NULL; 232 /* 233 * At the moment, journaled soft updates cannot support 234 * taking snapshots. 235 */ 236 if (MOUNTEDSUJ(mp)) { 237 vfs_mount_error(mp, "%s: Snapshots are not yet supported when " 238 "running with journaled soft updates", fs->fs_fsmnt); 239 return (EOPNOTSUPP); 240 } 241 MNT_ILOCK(mp); 242 flag = mp->mnt_flag; 243 MNT_IUNLOCK(mp); 244 /* 245 * Need to serialize access to snapshot code per filesystem. 246 */ 247 /* 248 * Assign a snapshot slot in the superblock. 249 */ 250 UFS_LOCK(ump); 251 for (snaploc = 0; snaploc < FSMAXSNAP; snaploc++) 252 if (fs->fs_snapinum[snaploc] == 0) 253 break; 254 UFS_UNLOCK(ump); 255 if (snaploc == FSMAXSNAP) 256 return (ENOSPC); 257 /* 258 * Create the snapshot file. 259 */ 260 restart: 261 NDINIT(&nd, CREATE, LOCKPARENT | LOCKLEAF | NOCACHE, UIO_SYSSPACE, 262 snapfile, td); 263 if ((error = namei(&nd)) != 0) 264 return (error); 265 if (nd.ni_vp != NULL) { 266 vput(nd.ni_vp); 267 error = EEXIST; 268 } 269 if (nd.ni_dvp->v_mount != mp) 270 error = EXDEV; 271 if (error) { 272 NDFREE(&nd, NDF_ONLY_PNBUF); 273 if (nd.ni_dvp == nd.ni_vp) 274 vrele(nd.ni_dvp); 275 else 276 vput(nd.ni_dvp); 277 return (error); 278 } 279 VATTR_NULL(&vat); 280 vat.va_type = VREG; 281 vat.va_mode = S_IRUSR; 282 vat.va_vaflags |= VA_EXCLUSIVE; 283 if (VOP_GETWRITEMOUNT(nd.ni_dvp, &wrtmp)) 284 wrtmp = NULL; 285 if (wrtmp != mp) 286 panic("ffs_snapshot: mount mismatch"); 287 vfs_rel(wrtmp); 288 if (vn_start_write(NULL, &wrtmp, V_NOWAIT) != 0) { 289 NDFREE(&nd, NDF_ONLY_PNBUF); 290 vput(nd.ni_dvp); 291 if ((error = vn_start_write(NULL, &wrtmp, 292 V_XSLEEP | PCATCH)) != 0) 293 return (error); 294 goto restart; 295 } 296 error = VOP_CREATE(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vat); 297 VOP_UNLOCK(nd.ni_dvp, 0); 298 if (error) { 299 NDFREE(&nd, NDF_ONLY_PNBUF); 300 vn_finished_write(wrtmp); 301 vrele(nd.ni_dvp); 302 return (error); 303 } 304 vp = nd.ni_vp; 305 vnode_create_vobject(nd.ni_vp, fs->fs_size, td); 306 vp->v_vflag |= VV_SYSTEM; 307 ip = VTOI(vp); 308 devvp = ITODEVVP(ip); 309 /* 310 * Allocate and copy the last block contents so as to be able 311 * to set size to that of the filesystem. 312 */ 313 numblks = howmany(fs->fs_size, fs->fs_frag); 314 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)(numblks - 1)), 315 fs->fs_bsize, KERNCRED, BA_CLRBUF, &bp); 316 if (error) 317 goto out; 318 ip->i_size = lblktosize(fs, (off_t)numblks); 319 DIP_SET(ip, i_size, ip->i_size); 320 ip->i_flag |= IN_CHANGE | IN_UPDATE; 321 error = readblock(vp, bp, numblks - 1); 322 bawrite(bp); 323 if (error != 0) 324 goto out; 325 /* 326 * Preallocate critical data structures so that we can copy 327 * them in without further allocation after we suspend all 328 * operations on the filesystem. We would like to just release 329 * the allocated buffers without writing them since they will 330 * be filled in below once we are ready to go, but this upsets 331 * the soft update code, so we go ahead and write the new buffers. 332 * 333 * Allocate all indirect blocks and mark all of them as not 334 * needing to be copied. 335 */ 336 for (blkno = UFS_NDADDR; blkno < numblks; blkno += NINDIR(fs)) { 337 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)blkno), 338 fs->fs_bsize, td->td_ucred, BA_METAONLY, &ibp); 339 if (error) 340 goto out; 341 bawrite(ibp); 342 } 343 /* 344 * Allocate copies for the superblock and its summary information. 345 */ 346 error = UFS_BALLOC(vp, fs->fs_sblockloc, fs->fs_sbsize, KERNCRED, 347 0, &nbp); 348 if (error) 349 goto out; 350 bawrite(nbp); 351 blkno = fragstoblks(fs, fs->fs_csaddr); 352 len = howmany(fs->fs_cssize, fs->fs_bsize); 353 for (loc = 0; loc < len; loc++) { 354 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)(blkno + loc)), 355 fs->fs_bsize, KERNCRED, 0, &nbp); 356 if (error) 357 goto out; 358 bawrite(nbp); 359 } 360 /* 361 * Allocate all cylinder group blocks. 362 */ 363 for (cg = 0; cg < fs->fs_ncg; cg++) { 364 error = UFS_BALLOC(vp, lfragtosize(fs, cgtod(fs, cg)), 365 fs->fs_bsize, KERNCRED, 0, &nbp); 366 if (error) 367 goto out; 368 bawrite(nbp); 369 if (cg % 10 == 0) 370 ffs_syncvnode(vp, MNT_WAIT, 0); 371 } 372 /* 373 * Copy all the cylinder group maps. Although the 374 * filesystem is still active, we hope that only a few 375 * cylinder groups will change between now and when we 376 * suspend operations. Thus, we will be able to quickly 377 * touch up the few cylinder groups that changed during 378 * the suspension period. 379 */ 380 len = howmany(fs->fs_ncg, NBBY); 381 space = malloc(len, M_DEVBUF, M_WAITOK|M_ZERO); 382 UFS_LOCK(ump); 383 fs->fs_active = space; 384 UFS_UNLOCK(ump); 385 for (cg = 0; cg < fs->fs_ncg; cg++) { 386 error = UFS_BALLOC(vp, lfragtosize(fs, cgtod(fs, cg)), 387 fs->fs_bsize, KERNCRED, 0, &nbp); 388 if (error) 389 goto out; 390 error = cgaccount(cg, vp, nbp, 1); 391 bawrite(nbp); 392 if (cg % 10 == 0) 393 ffs_syncvnode(vp, MNT_WAIT, 0); 394 if (error) 395 goto out; 396 } 397 /* 398 * Change inode to snapshot type file. 399 */ 400 ip->i_flags |= SF_SNAPSHOT; 401 DIP_SET(ip, i_flags, ip->i_flags); 402 ip->i_flag |= IN_CHANGE | IN_UPDATE; 403 /* 404 * Ensure that the snapshot is completely on disk. 405 * Since we have marked it as a snapshot it is safe to 406 * unlock it as no process will be allowed to write to it. 407 */ 408 if ((error = ffs_syncvnode(vp, MNT_WAIT, 0)) != 0) 409 goto out; 410 VOP_UNLOCK(vp, 0); 411 /* 412 * All allocations are done, so we can now snapshot the system. 413 * 414 * Recind nice scheduling while running with the filesystem suspended. 415 */ 416 if (td->td_proc->p_nice > 0) { 417 struct proc *p; 418 419 p = td->td_proc; 420 PROC_LOCK(p); 421 saved_nice = p->p_nice; 422 sched_nice(p, 0); 423 PROC_UNLOCK(p); 424 } 425 /* 426 * Suspend operation on filesystem. 427 */ 428 for (;;) { 429 vn_finished_write(wrtmp); 430 if ((error = vfs_write_suspend(vp->v_mount, 0)) != 0) { 431 vn_start_write(NULL, &wrtmp, V_WAIT); 432 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 433 goto out; 434 } 435 if (mp->mnt_kern_flag & MNTK_SUSPENDED) 436 break; 437 vn_start_write(NULL, &wrtmp, V_WAIT); 438 } 439 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 440 if (ip->i_effnlink == 0) { 441 error = ENOENT; /* Snapshot file unlinked */ 442 goto out1; 443 } 444 if (collectsnapstats) 445 nanotime(&starttime); 446 447 /* The last block might have changed. Copy it again to be sure. */ 448 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)(numblks - 1)), 449 fs->fs_bsize, KERNCRED, BA_CLRBUF, &bp); 450 if (error != 0) 451 goto out1; 452 error = readblock(vp, bp, numblks - 1); 453 bp->b_flags |= B_VALIDSUSPWRT; 454 bawrite(bp); 455 if (error != 0) 456 goto out1; 457 /* 458 * First, copy all the cylinder group maps that have changed. 459 */ 460 for (cg = 0; cg < fs->fs_ncg; cg++) { 461 if ((ACTIVECGNUM(fs, cg) & ACTIVECGOFF(cg)) != 0) 462 continue; 463 redo++; 464 error = UFS_BALLOC(vp, lfragtosize(fs, cgtod(fs, cg)), 465 fs->fs_bsize, KERNCRED, 0, &nbp); 466 if (error) 467 goto out1; 468 error = cgaccount(cg, vp, nbp, 2); 469 bawrite(nbp); 470 if (error) 471 goto out1; 472 } 473 /* 474 * Grab a copy of the superblock and its summary information. 475 * We delay writing it until the suspension is released below. 476 */ 477 copy_fs = malloc((u_long)fs->fs_bsize, M_UFSMNT, M_WAITOK); 478 bcopy(fs, copy_fs, fs->fs_sbsize); 479 if ((fs->fs_flags & (FS_UNCLEAN | FS_NEEDSFSCK)) == 0) 480 copy_fs->fs_clean = 1; 481 size = fs->fs_bsize < SBLOCKSIZE ? fs->fs_bsize : SBLOCKSIZE; 482 if (fs->fs_sbsize < size) 483 bzero(&((char *)copy_fs)[fs->fs_sbsize], 484 size - fs->fs_sbsize); 485 size = blkroundup(fs, fs->fs_cssize); 486 if (fs->fs_contigsumsize > 0) 487 size += fs->fs_ncg * sizeof(int32_t); 488 space = malloc((u_long)size, M_UFSMNT, M_WAITOK); 489 copy_fs->fs_csp = space; 490 bcopy(fs->fs_csp, copy_fs->fs_csp, fs->fs_cssize); 491 space = (char *)space + fs->fs_cssize; 492 loc = howmany(fs->fs_cssize, fs->fs_fsize); 493 i = fs->fs_frag - loc % fs->fs_frag; 494 len = (i == fs->fs_frag) ? 0 : i * fs->fs_fsize; 495 if (len > 0) { 496 if ((error = bread(devvp, fsbtodb(fs, fs->fs_csaddr + loc), 497 len, KERNCRED, &bp)) != 0) { 498 brelse(bp); 499 free(copy_fs->fs_csp, M_UFSMNT); 500 free(copy_fs, M_UFSMNT); 501 copy_fs = NULL; 502 goto out1; 503 } 504 bcopy(bp->b_data, space, (u_int)len); 505 space = (char *)space + len; 506 bp->b_flags |= B_INVAL | B_NOCACHE; 507 brelse(bp); 508 } 509 if (fs->fs_contigsumsize > 0) { 510 copy_fs->fs_maxcluster = lp = space; 511 for (i = 0; i < fs->fs_ncg; i++) 512 *lp++ = fs->fs_contigsumsize; 513 } 514 /* 515 * We must check for active files that have been unlinked 516 * (e.g., with a zero link count). We have to expunge all 517 * trace of these files from the snapshot so that they are 518 * not reclaimed prematurely by fsck or unnecessarily dumped. 519 * We turn off the MNTK_SUSPENDED flag to avoid a panic from 520 * spec_strategy about writing on a suspended filesystem. 521 * Note that we skip unlinked snapshot files as they will 522 * be handled separately below. 523 * 524 * We also calculate the needed size for the snapshot list. 525 */ 526 snaplistsize = fs->fs_ncg + howmany(fs->fs_cssize, fs->fs_bsize) + 527 FSMAXSNAP + 1 /* superblock */ + 1 /* last block */ + 1 /* size */; 528 MNT_ILOCK(mp); 529 mp->mnt_kern_flag &= ~MNTK_SUSPENDED; 530 MNT_IUNLOCK(mp); 531 loop: 532 MNT_VNODE_FOREACH_ALL(xvp, mp, mvp) { 533 if ((xvp->v_usecount == 0 && 534 (xvp->v_iflag & (VI_OWEINACT | VI_DOINGINACT)) == 0) || 535 xvp->v_type == VNON || 536 IS_SNAPSHOT(VTOI(xvp))) { 537 VI_UNLOCK(xvp); 538 continue; 539 } 540 /* 541 * We can skip parent directory vnode because it must have 542 * this snapshot file in it. 543 */ 544 if (xvp == nd.ni_dvp) { 545 VI_UNLOCK(xvp); 546 continue; 547 } 548 vholdl(xvp); 549 if (vn_lock(xvp, LK_EXCLUSIVE | LK_INTERLOCK) != 0) { 550 MNT_VNODE_FOREACH_ALL_ABORT(mp, mvp); 551 vdrop(xvp); 552 goto loop; 553 } 554 VI_LOCK(xvp); 555 if (xvp->v_usecount == 0 && 556 (xvp->v_iflag & (VI_OWEINACT | VI_DOINGINACT)) == 0) { 557 VI_UNLOCK(xvp); 558 VOP_UNLOCK(xvp, 0); 559 vdrop(xvp); 560 continue; 561 } 562 VI_UNLOCK(xvp); 563 if (snapdebug) 564 vn_printf(xvp, "ffs_snapshot: busy vnode "); 565 if (VOP_GETATTR(xvp, &vat, td->td_ucred) == 0 && 566 vat.va_nlink > 0) { 567 VOP_UNLOCK(xvp, 0); 568 vdrop(xvp); 569 continue; 570 } 571 xp = VTOI(xvp); 572 if (ffs_checkfreefile(copy_fs, vp, xp->i_number)) { 573 VOP_UNLOCK(xvp, 0); 574 vdrop(xvp); 575 continue; 576 } 577 /* 578 * If there is a fragment, clear it here. 579 */ 580 blkno = 0; 581 loc = howmany(xp->i_size, fs->fs_bsize) - 1; 582 if (loc < UFS_NDADDR) { 583 len = fragroundup(fs, blkoff(fs, xp->i_size)); 584 if (len != 0 && len < fs->fs_bsize) { 585 ffs_blkfree(ump, copy_fs, vp, 586 DIP(xp, i_db[loc]), len, xp->i_number, 587 xvp->v_type, NULL, SINGLETON_KEY); 588 blkno = DIP(xp, i_db[loc]); 589 DIP_SET(xp, i_db[loc], 0); 590 } 591 } 592 snaplistsize += 1; 593 if (I_IS_UFS1(xp)) 594 error = expunge_ufs1(vp, xp, copy_fs, fullacct_ufs1, 595 BLK_NOCOPY, 1); 596 else 597 error = expunge_ufs2(vp, xp, copy_fs, fullacct_ufs2, 598 BLK_NOCOPY, 1); 599 if (blkno) 600 DIP_SET(xp, i_db[loc], blkno); 601 if (!error) 602 error = ffs_freefile(ump, copy_fs, vp, xp->i_number, 603 xp->i_mode, NULL); 604 VOP_UNLOCK(xvp, 0); 605 vdrop(xvp); 606 if (error) { 607 free(copy_fs->fs_csp, M_UFSMNT); 608 free(copy_fs, M_UFSMNT); 609 copy_fs = NULL; 610 MNT_VNODE_FOREACH_ALL_ABORT(mp, mvp); 611 goto out1; 612 } 613 } 614 /* 615 * Erase the journal file from the snapshot. 616 */ 617 if (fs->fs_flags & FS_SUJ) { 618 error = softdep_journal_lookup(mp, &xvp); 619 if (error) { 620 free(copy_fs->fs_csp, M_UFSMNT); 621 free(copy_fs, M_UFSMNT); 622 copy_fs = NULL; 623 goto out1; 624 } 625 xp = VTOI(xvp); 626 if (I_IS_UFS1(xp)) 627 error = expunge_ufs1(vp, xp, copy_fs, fullacct_ufs1, 628 BLK_NOCOPY, 0); 629 else 630 error = expunge_ufs2(vp, xp, copy_fs, fullacct_ufs2, 631 BLK_NOCOPY, 0); 632 vput(xvp); 633 } 634 /* 635 * Acquire a lock on the snapdata structure, creating it if necessary. 636 */ 637 sn = ffs_snapdata_acquire(devvp); 638 /* 639 * Change vnode to use shared snapshot lock instead of the original 640 * private lock. 641 */ 642 vp->v_vnlock = &sn->sn_lock; 643 lockmgr(&vp->v_lock, LK_RELEASE, NULL); 644 xp = TAILQ_FIRST(&sn->sn_head); 645 /* 646 * If this is the first snapshot on this filesystem, then we need 647 * to allocate the space for the list of preallocated snapshot blocks. 648 * This list will be refined below, but this preliminary one will 649 * keep us out of deadlock until the full one is ready. 650 */ 651 if (xp == NULL) { 652 snapblklist = malloc(snaplistsize * sizeof(daddr_t), 653 M_UFSMNT, M_WAITOK); 654 blkp = &snapblklist[1]; 655 *blkp++ = lblkno(fs, fs->fs_sblockloc); 656 blkno = fragstoblks(fs, fs->fs_csaddr); 657 for (cg = 0; cg < fs->fs_ncg; cg++) { 658 if (fragstoblks(fs, cgtod(fs, cg) > blkno)) 659 break; 660 *blkp++ = fragstoblks(fs, cgtod(fs, cg)); 661 } 662 len = howmany(fs->fs_cssize, fs->fs_bsize); 663 for (loc = 0; loc < len; loc++) 664 *blkp++ = blkno + loc; 665 for (; cg < fs->fs_ncg; cg++) 666 *blkp++ = fragstoblks(fs, cgtod(fs, cg)); 667 snapblklist[0] = blkp - snapblklist; 668 VI_LOCK(devvp); 669 if (sn->sn_blklist != NULL) 670 panic("ffs_snapshot: non-empty list"); 671 sn->sn_blklist = snapblklist; 672 sn->sn_listsize = blkp - snapblklist; 673 VI_UNLOCK(devvp); 674 } 675 /* 676 * Record snapshot inode. Since this is the newest snapshot, 677 * it must be placed at the end of the list. 678 */ 679 VI_LOCK(devvp); 680 fs->fs_snapinum[snaploc] = ip->i_number; 681 if (ip->i_nextsnap.tqe_prev != 0) 682 panic("ffs_snapshot: %ju already on list", 683 (uintmax_t)ip->i_number); 684 TAILQ_INSERT_TAIL(&sn->sn_head, ip, i_nextsnap); 685 devvp->v_vflag |= VV_COPYONWRITE; 686 VI_UNLOCK(devvp); 687 ASSERT_VOP_LOCKED(vp, "ffs_snapshot vp"); 688 out1: 689 KASSERT((sn != NULL && copy_fs != NULL && error == 0) || 690 (sn == NULL && copy_fs == NULL && error != 0), 691 ("email phk@ and mckusick@")); 692 /* 693 * Resume operation on filesystem. 694 */ 695 vfs_write_resume(vp->v_mount, VR_START_WRITE | VR_NO_SUSPCLR); 696 if (collectsnapstats && starttime.tv_sec > 0) { 697 nanotime(&endtime); 698 timespecsub(&endtime, &starttime, &endtime); 699 printf("%s: suspended %ld.%03ld sec, redo %ld of %d\n", 700 vp->v_mount->mnt_stat.f_mntonname, (long)endtime.tv_sec, 701 endtime.tv_nsec / 1000000, redo, fs->fs_ncg); 702 } 703 if (copy_fs == NULL) 704 goto out; 705 /* 706 * Copy allocation information from all the snapshots in 707 * this snapshot and then expunge them from its view. 708 */ 709 TAILQ_FOREACH(xp, &sn->sn_head, i_nextsnap) { 710 if (xp == ip) 711 break; 712 if (I_IS_UFS1(xp)) 713 error = expunge_ufs1(vp, xp, fs, snapacct_ufs1, 714 BLK_SNAP, 0); 715 else 716 error = expunge_ufs2(vp, xp, fs, snapacct_ufs2, 717 BLK_SNAP, 0); 718 if (error == 0 && xp->i_effnlink == 0) { 719 error = ffs_freefile(ump, 720 copy_fs, 721 vp, 722 xp->i_number, 723 xp->i_mode, NULL); 724 } 725 if (error) { 726 fs->fs_snapinum[snaploc] = 0; 727 goto done; 728 } 729 } 730 /* 731 * Allocate space for the full list of preallocated snapshot blocks. 732 */ 733 snapblklist = malloc(snaplistsize * sizeof(daddr_t), 734 M_UFSMNT, M_WAITOK); 735 ip->i_snapblklist = &snapblklist[1]; 736 /* 737 * Expunge the blocks used by the snapshots from the set of 738 * blocks marked as used in the snapshot bitmaps. Also, collect 739 * the list of allocated blocks in i_snapblklist. 740 */ 741 if (I_IS_UFS1(ip)) 742 error = expunge_ufs1(vp, ip, copy_fs, mapacct_ufs1, 743 BLK_SNAP, 0); 744 else 745 error = expunge_ufs2(vp, ip, copy_fs, mapacct_ufs2, 746 BLK_SNAP, 0); 747 if (error) { 748 fs->fs_snapinum[snaploc] = 0; 749 free(snapblklist, M_UFSMNT); 750 goto done; 751 } 752 if (snaplistsize < ip->i_snapblklist - snapblklist) 753 panic("ffs_snapshot: list too small"); 754 snaplistsize = ip->i_snapblklist - snapblklist; 755 snapblklist[0] = snaplistsize; 756 ip->i_snapblklist = 0; 757 /* 758 * Write out the list of allocated blocks to the end of the snapshot. 759 */ 760 auio.uio_iov = &aiov; 761 auio.uio_iovcnt = 1; 762 aiov.iov_base = (void *)snapblklist; 763 aiov.iov_len = snaplistsize * sizeof(daddr_t); 764 auio.uio_resid = aiov.iov_len; 765 auio.uio_offset = ip->i_size; 766 auio.uio_segflg = UIO_SYSSPACE; 767 auio.uio_rw = UIO_WRITE; 768 auio.uio_td = td; 769 if ((error = VOP_WRITE(vp, &auio, IO_UNIT, td->td_ucred)) != 0) { 770 fs->fs_snapinum[snaploc] = 0; 771 free(snapblklist, M_UFSMNT); 772 goto done; 773 } 774 /* 775 * Write the superblock and its summary information 776 * to the snapshot. 777 */ 778 blkno = fragstoblks(fs, fs->fs_csaddr); 779 len = howmany(fs->fs_cssize, fs->fs_bsize); 780 space = copy_fs->fs_csp; 781 for (loc = 0; loc < len; loc++) { 782 error = bread(vp, blkno + loc, fs->fs_bsize, KERNCRED, &nbp); 783 if (error) { 784 brelse(nbp); 785 fs->fs_snapinum[snaploc] = 0; 786 free(snapblklist, M_UFSMNT); 787 goto done; 788 } 789 bcopy(space, nbp->b_data, fs->fs_bsize); 790 space = (char *)space + fs->fs_bsize; 791 bawrite(nbp); 792 } 793 error = bread(vp, lblkno(fs, fs->fs_sblockloc), fs->fs_bsize, 794 KERNCRED, &nbp); 795 if (error) { 796 brelse(nbp); 797 } else { 798 loc = blkoff(fs, fs->fs_sblockloc); 799 copy_fs->fs_ckhash = ffs_calc_sbhash(copy_fs); 800 bcopy((char *)copy_fs, &nbp->b_data[loc], (u_int)fs->fs_sbsize); 801 bawrite(nbp); 802 } 803 /* 804 * As this is the newest list, it is the most inclusive, so 805 * should replace the previous list. 806 */ 807 VI_LOCK(devvp); 808 space = sn->sn_blklist; 809 sn->sn_blklist = snapblklist; 810 sn->sn_listsize = snaplistsize; 811 VI_UNLOCK(devvp); 812 if (space != NULL) 813 free(space, M_UFSMNT); 814 /* 815 * Preallocate all the direct blocks in the snapshot inode so 816 * that we never have to write the inode itself to commit an 817 * update to the contents of the snapshot. Note that once 818 * created, the size of the snapshot will never change, so 819 * there will never be a need to write the inode except to 820 * update the non-integrity-critical time fields and 821 * allocated-block count. 822 */ 823 for (blockno = 0; blockno < UFS_NDADDR; blockno++) { 824 if (DIP(ip, i_db[blockno]) != 0) 825 continue; 826 error = UFS_BALLOC(vp, lblktosize(fs, blockno), 827 fs->fs_bsize, KERNCRED, BA_CLRBUF, &bp); 828 if (error) 829 break; 830 error = readblock(vp, bp, blockno); 831 bawrite(bp); 832 if (error != 0) 833 break; 834 } 835 done: 836 free(copy_fs->fs_csp, M_UFSMNT); 837 free(copy_fs, M_UFSMNT); 838 copy_fs = NULL; 839 out: 840 NDFREE(&nd, NDF_ONLY_PNBUF); 841 if (saved_nice > 0) { 842 struct proc *p; 843 844 p = td->td_proc; 845 PROC_LOCK(p); 846 sched_nice(td->td_proc, saved_nice); 847 PROC_UNLOCK(td->td_proc); 848 } 849 UFS_LOCK(ump); 850 if (fs->fs_active != 0) { 851 free(fs->fs_active, M_DEVBUF); 852 fs->fs_active = 0; 853 } 854 UFS_UNLOCK(ump); 855 MNT_ILOCK(mp); 856 mp->mnt_flag = (mp->mnt_flag & MNT_QUOTA) | (flag & ~MNT_QUOTA); 857 MNT_IUNLOCK(mp); 858 if (error) 859 (void) ffs_truncate(vp, (off_t)0, 0, NOCRED); 860 (void) ffs_syncvnode(vp, MNT_WAIT, 0); 861 if (error) 862 vput(vp); 863 else 864 VOP_UNLOCK(vp, 0); 865 vrele(nd.ni_dvp); 866 vn_finished_write(wrtmp); 867 process_deferred_inactive(mp); 868 return (error); 869 } 870 871 /* 872 * Copy a cylinder group map. All the unallocated blocks are marked 873 * BLK_NOCOPY so that the snapshot knows that it need not copy them 874 * if they are later written. If passno is one, then this is a first 875 * pass, so only setting needs to be done. If passno is 2, then this 876 * is a revision to a previous pass which must be undone as the 877 * replacement pass is done. 878 */ 879 static int 880 cgaccount(cg, vp, nbp, passno) 881 int cg; 882 struct vnode *vp; 883 struct buf *nbp; 884 int passno; 885 { 886 struct buf *bp, *ibp; 887 struct inode *ip; 888 struct cg *cgp; 889 struct fs *fs; 890 ufs2_daddr_t base, numblks; 891 int error, len, loc, indiroff; 892 893 ip = VTOI(vp); 894 fs = ITOFS(ip); 895 if ((error = ffs_getcg(fs, ITODEVVP(ip), cg, &bp, &cgp)) != 0) 896 return (error); 897 UFS_LOCK(ITOUMP(ip)); 898 ACTIVESET(fs, cg); 899 /* 900 * Recomputation of summary information might not have been performed 901 * at mount time. Sync up summary information for current cylinder 902 * group while data is in memory to ensure that result of background 903 * fsck is slightly more consistent. 904 */ 905 fs->fs_cs(fs, cg) = cgp->cg_cs; 906 UFS_UNLOCK(ITOUMP(ip)); 907 bcopy(bp->b_data, nbp->b_data, fs->fs_cgsize); 908 if (fs->fs_cgsize < fs->fs_bsize) 909 bzero(&nbp->b_data[fs->fs_cgsize], 910 fs->fs_bsize - fs->fs_cgsize); 911 cgp = (struct cg *)nbp->b_data; 912 bqrelse(bp); 913 if (passno == 2) 914 nbp->b_flags |= B_VALIDSUSPWRT; 915 numblks = howmany(fs->fs_size, fs->fs_frag); 916 len = howmany(fs->fs_fpg, fs->fs_frag); 917 base = cgbase(fs, cg) / fs->fs_frag; 918 if (base + len >= numblks) 919 len = numblks - base - 1; 920 loc = 0; 921 if (base < UFS_NDADDR) { 922 for ( ; loc < UFS_NDADDR; loc++) { 923 if (ffs_isblock(fs, cg_blksfree(cgp), loc)) 924 DIP_SET(ip, i_db[loc], BLK_NOCOPY); 925 else if (passno == 2 && DIP(ip, i_db[loc])== BLK_NOCOPY) 926 DIP_SET(ip, i_db[loc], 0); 927 else if (passno == 1 && DIP(ip, i_db[loc])== BLK_NOCOPY) 928 panic("ffs_snapshot: lost direct block"); 929 } 930 } 931 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)(base + loc)), 932 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp); 933 if (error) { 934 goto out; 935 } 936 indiroff = (base + loc - UFS_NDADDR) % NINDIR(fs); 937 for ( ; loc < len; loc++, indiroff++) { 938 if (indiroff >= NINDIR(fs)) { 939 if (passno == 2) 940 ibp->b_flags |= B_VALIDSUSPWRT; 941 bawrite(ibp); 942 error = UFS_BALLOC(vp, 943 lblktosize(fs, (off_t)(base + loc)), 944 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp); 945 if (error) { 946 goto out; 947 } 948 indiroff = 0; 949 } 950 if (I_IS_UFS1(ip)) { 951 if (ffs_isblock(fs, cg_blksfree(cgp), loc)) 952 ((ufs1_daddr_t *)(ibp->b_data))[indiroff] = 953 BLK_NOCOPY; 954 else if (passno == 2 && ((ufs1_daddr_t *)(ibp->b_data)) 955 [indiroff] == BLK_NOCOPY) 956 ((ufs1_daddr_t *)(ibp->b_data))[indiroff] = 0; 957 else if (passno == 1 && ((ufs1_daddr_t *)(ibp->b_data)) 958 [indiroff] == BLK_NOCOPY) 959 panic("ffs_snapshot: lost indirect block"); 960 continue; 961 } 962 if (ffs_isblock(fs, cg_blksfree(cgp), loc)) 963 ((ufs2_daddr_t *)(ibp->b_data))[indiroff] = BLK_NOCOPY; 964 else if (passno == 2 && 965 ((ufs2_daddr_t *)(ibp->b_data)) [indiroff] == BLK_NOCOPY) 966 ((ufs2_daddr_t *)(ibp->b_data))[indiroff] = 0; 967 else if (passno == 1 && 968 ((ufs2_daddr_t *)(ibp->b_data)) [indiroff] == BLK_NOCOPY) 969 panic("ffs_snapshot: lost indirect block"); 970 } 971 if (passno == 2) 972 ibp->b_flags |= B_VALIDSUSPWRT; 973 bdwrite(ibp); 974 out: 975 /* 976 * We have to calculate the crc32c here rather than just setting the 977 * BX_CYLGRP b_xflags because the allocation of the block for the 978 * the cylinder group map will always be a full size block (fs_bsize) 979 * even though the cylinder group may be smaller (fs_cgsize). The 980 * crc32c must be computed only over fs_cgsize whereas the BX_CYLGRP 981 * flag causes it to be computed over the size of the buffer. 982 */ 983 if ((fs->fs_metackhash & CK_CYLGRP) != 0) { 984 ((struct cg *)nbp->b_data)->cg_ckhash = 0; 985 ((struct cg *)nbp->b_data)->cg_ckhash = 986 calculate_crc32c(~0L, nbp->b_data, fs->fs_cgsize); 987 } 988 return (error); 989 } 990 991 /* 992 * Before expunging a snapshot inode, note all the 993 * blocks that it claims with BLK_SNAP so that fsck will 994 * be able to account for those blocks properly and so 995 * that this snapshot knows that it need not copy them 996 * if the other snapshot holding them is freed. This code 997 * is reproduced once each for UFS1 and UFS2. 998 */ 999 static int 1000 expunge_ufs1(snapvp, cancelip, fs, acctfunc, expungetype, clearmode) 1001 struct vnode *snapvp; 1002 struct inode *cancelip; 1003 struct fs *fs; 1004 int (*acctfunc)(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *, 1005 struct fs *, ufs_lbn_t, int); 1006 int expungetype; 1007 int clearmode; 1008 { 1009 int i, error, indiroff; 1010 ufs_lbn_t lbn, rlbn; 1011 ufs2_daddr_t len, blkno, numblks, blksperindir; 1012 struct ufs1_dinode *dip; 1013 struct thread *td = curthread; 1014 struct buf *bp; 1015 1016 /* 1017 * Prepare to expunge the inode. If its inode block has not 1018 * yet been copied, then allocate and fill the copy. 1019 */ 1020 lbn = fragstoblks(fs, ino_to_fsba(fs, cancelip->i_number)); 1021 blkno = 0; 1022 if (lbn < UFS_NDADDR) { 1023 blkno = VTOI(snapvp)->i_din1->di_db[lbn]; 1024 } else { 1025 if (DOINGSOFTDEP(snapvp)) 1026 softdep_prealloc(snapvp, MNT_WAIT); 1027 td->td_pflags |= TDP_COWINPROGRESS; 1028 error = ffs_balloc_ufs1(snapvp, lblktosize(fs, (off_t)lbn), 1029 fs->fs_bsize, KERNCRED, BA_METAONLY, &bp); 1030 td->td_pflags &= ~TDP_COWINPROGRESS; 1031 if (error) 1032 return (error); 1033 indiroff = (lbn - UFS_NDADDR) % NINDIR(fs); 1034 blkno = ((ufs1_daddr_t *)(bp->b_data))[indiroff]; 1035 bqrelse(bp); 1036 } 1037 if (blkno != 0) { 1038 if ((error = bread(snapvp, lbn, fs->fs_bsize, KERNCRED, &bp))) 1039 return (error); 1040 } else { 1041 error = ffs_balloc_ufs1(snapvp, lblktosize(fs, (off_t)lbn), 1042 fs->fs_bsize, KERNCRED, 0, &bp); 1043 if (error) 1044 return (error); 1045 if ((error = readblock(snapvp, bp, lbn)) != 0) 1046 return (error); 1047 } 1048 /* 1049 * Set a snapshot inode to be a zero length file, regular files 1050 * or unlinked snapshots to be completely unallocated. 1051 */ 1052 dip = (struct ufs1_dinode *)bp->b_data + 1053 ino_to_fsbo(fs, cancelip->i_number); 1054 if (clearmode || cancelip->i_effnlink == 0) 1055 dip->di_mode = 0; 1056 dip->di_size = 0; 1057 dip->di_blocks = 0; 1058 dip->di_flags &= ~SF_SNAPSHOT; 1059 bzero(&dip->di_db[0], (UFS_NDADDR + UFS_NIADDR) * sizeof(ufs1_daddr_t)); 1060 bdwrite(bp); 1061 /* 1062 * Now go through and expunge all the blocks in the file 1063 * using the function requested. 1064 */ 1065 numblks = howmany(cancelip->i_size, fs->fs_bsize); 1066 if ((error = (*acctfunc)(snapvp, &cancelip->i_din1->di_db[0], 1067 &cancelip->i_din1->di_db[UFS_NDADDR], fs, 0, expungetype))) 1068 return (error); 1069 if ((error = (*acctfunc)(snapvp, &cancelip->i_din1->di_ib[0], 1070 &cancelip->i_din1->di_ib[UFS_NIADDR], fs, -1, expungetype))) 1071 return (error); 1072 blksperindir = 1; 1073 lbn = -UFS_NDADDR; 1074 len = numblks - UFS_NDADDR; 1075 rlbn = UFS_NDADDR; 1076 for (i = 0; len > 0 && i < UFS_NIADDR; i++) { 1077 error = indiracct_ufs1(snapvp, ITOV(cancelip), i, 1078 cancelip->i_din1->di_ib[i], lbn, rlbn, len, 1079 blksperindir, fs, acctfunc, expungetype); 1080 if (error) 1081 return (error); 1082 blksperindir *= NINDIR(fs); 1083 lbn -= blksperindir + 1; 1084 len -= blksperindir; 1085 rlbn += blksperindir; 1086 } 1087 return (0); 1088 } 1089 1090 /* 1091 * Descend an indirect block chain for vnode cancelvp accounting for all 1092 * its indirect blocks in snapvp. 1093 */ 1094 static int 1095 indiracct_ufs1(snapvp, cancelvp, level, blkno, lbn, rlbn, remblks, 1096 blksperindir, fs, acctfunc, expungetype) 1097 struct vnode *snapvp; 1098 struct vnode *cancelvp; 1099 int level; 1100 ufs1_daddr_t blkno; 1101 ufs_lbn_t lbn; 1102 ufs_lbn_t rlbn; 1103 ufs_lbn_t remblks; 1104 ufs_lbn_t blksperindir; 1105 struct fs *fs; 1106 int (*acctfunc)(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *, 1107 struct fs *, ufs_lbn_t, int); 1108 int expungetype; 1109 { 1110 int error, num, i; 1111 ufs_lbn_t subblksperindir; 1112 struct indir indirs[UFS_NIADDR + 2]; 1113 ufs1_daddr_t last, *bap; 1114 struct buf *bp; 1115 1116 if (blkno == 0) { 1117 if (expungetype == BLK_NOCOPY) 1118 return (0); 1119 panic("indiracct_ufs1: missing indir"); 1120 } 1121 if ((error = ufs_getlbns(cancelvp, rlbn, indirs, &num)) != 0) 1122 return (error); 1123 if (lbn != indirs[num - 1 - level].in_lbn || num < 2) 1124 panic("indiracct_ufs1: botched params"); 1125 /* 1126 * We have to expand bread here since it will deadlock looking 1127 * up the block number for any blocks that are not in the cache. 1128 */ 1129 bp = getblk(cancelvp, lbn, fs->fs_bsize, 0, 0, 0); 1130 bp->b_blkno = fsbtodb(fs, blkno); 1131 if ((bp->b_flags & (B_DONE | B_DELWRI)) == 0 && 1132 (error = readblock(cancelvp, bp, fragstoblks(fs, blkno)))) { 1133 brelse(bp); 1134 return (error); 1135 } 1136 /* 1137 * Account for the block pointers in this indirect block. 1138 */ 1139 last = howmany(remblks, blksperindir); 1140 if (last > NINDIR(fs)) 1141 last = NINDIR(fs); 1142 bap = malloc(fs->fs_bsize, M_DEVBUF, M_WAITOK); 1143 bcopy(bp->b_data, (caddr_t)bap, fs->fs_bsize); 1144 bqrelse(bp); 1145 error = (*acctfunc)(snapvp, &bap[0], &bap[last], fs, 1146 level == 0 ? rlbn : -1, expungetype); 1147 if (error || level == 0) 1148 goto out; 1149 /* 1150 * Account for the block pointers in each of the indirect blocks 1151 * in the levels below us. 1152 */ 1153 subblksperindir = blksperindir / NINDIR(fs); 1154 for (lbn++, level--, i = 0; i < last; i++) { 1155 error = indiracct_ufs1(snapvp, cancelvp, level, bap[i], lbn, 1156 rlbn, remblks, subblksperindir, fs, acctfunc, expungetype); 1157 if (error) 1158 goto out; 1159 rlbn += blksperindir; 1160 lbn -= blksperindir; 1161 remblks -= blksperindir; 1162 } 1163 out: 1164 free(bap, M_DEVBUF); 1165 return (error); 1166 } 1167 1168 /* 1169 * Do both snap accounting and map accounting. 1170 */ 1171 static int 1172 fullacct_ufs1(vp, oldblkp, lastblkp, fs, lblkno, exptype) 1173 struct vnode *vp; 1174 ufs1_daddr_t *oldblkp, *lastblkp; 1175 struct fs *fs; 1176 ufs_lbn_t lblkno; 1177 int exptype; /* BLK_SNAP or BLK_NOCOPY */ 1178 { 1179 int error; 1180 1181 if ((error = snapacct_ufs1(vp, oldblkp, lastblkp, fs, lblkno, exptype))) 1182 return (error); 1183 return (mapacct_ufs1(vp, oldblkp, lastblkp, fs, lblkno, exptype)); 1184 } 1185 1186 /* 1187 * Identify a set of blocks allocated in a snapshot inode. 1188 */ 1189 static int 1190 snapacct_ufs1(vp, oldblkp, lastblkp, fs, lblkno, expungetype) 1191 struct vnode *vp; 1192 ufs1_daddr_t *oldblkp, *lastblkp; 1193 struct fs *fs; 1194 ufs_lbn_t lblkno; 1195 int expungetype; /* BLK_SNAP or BLK_NOCOPY */ 1196 { 1197 struct inode *ip = VTOI(vp); 1198 ufs1_daddr_t blkno, *blkp; 1199 ufs_lbn_t lbn; 1200 struct buf *ibp; 1201 int error; 1202 1203 for ( ; oldblkp < lastblkp; oldblkp++) { 1204 blkno = *oldblkp; 1205 if (blkno == 0 || blkno == BLK_NOCOPY || blkno == BLK_SNAP) 1206 continue; 1207 lbn = fragstoblks(fs, blkno); 1208 if (lbn < UFS_NDADDR) { 1209 blkp = &ip->i_din1->di_db[lbn]; 1210 ip->i_flag |= IN_CHANGE | IN_UPDATE; 1211 } else { 1212 error = ffs_balloc_ufs1(vp, lblktosize(fs, (off_t)lbn), 1213 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp); 1214 if (error) 1215 return (error); 1216 blkp = &((ufs1_daddr_t *)(ibp->b_data)) 1217 [(lbn - UFS_NDADDR) % NINDIR(fs)]; 1218 } 1219 /* 1220 * If we are expunging a snapshot vnode and we 1221 * find a block marked BLK_NOCOPY, then it is 1222 * one that has been allocated to this snapshot after 1223 * we took our current snapshot and can be ignored. 1224 */ 1225 if (expungetype == BLK_SNAP && *blkp == BLK_NOCOPY) { 1226 if (lbn >= UFS_NDADDR) 1227 brelse(ibp); 1228 } else { 1229 if (*blkp != 0) 1230 panic("snapacct_ufs1: bad block"); 1231 *blkp = expungetype; 1232 if (lbn >= UFS_NDADDR) 1233 bdwrite(ibp); 1234 } 1235 } 1236 return (0); 1237 } 1238 1239 /* 1240 * Account for a set of blocks allocated in a snapshot inode. 1241 */ 1242 static int 1243 mapacct_ufs1(vp, oldblkp, lastblkp, fs, lblkno, expungetype) 1244 struct vnode *vp; 1245 ufs1_daddr_t *oldblkp, *lastblkp; 1246 struct fs *fs; 1247 ufs_lbn_t lblkno; 1248 int expungetype; 1249 { 1250 ufs1_daddr_t blkno; 1251 struct inode *ip; 1252 ino_t inum; 1253 int acctit; 1254 1255 ip = VTOI(vp); 1256 inum = ip->i_number; 1257 if (lblkno == -1) 1258 acctit = 0; 1259 else 1260 acctit = 1; 1261 for ( ; oldblkp < lastblkp; oldblkp++, lblkno++) { 1262 blkno = *oldblkp; 1263 if (blkno == 0 || blkno == BLK_NOCOPY) 1264 continue; 1265 if (acctit && expungetype == BLK_SNAP && blkno != BLK_SNAP) 1266 *ip->i_snapblklist++ = lblkno; 1267 if (blkno == BLK_SNAP) 1268 blkno = blkstofrags(fs, lblkno); 1269 ffs_blkfree(ITOUMP(ip), fs, vp, blkno, fs->fs_bsize, inum, 1270 vp->v_type, NULL, SINGLETON_KEY); 1271 } 1272 return (0); 1273 } 1274 1275 /* 1276 * Before expunging a snapshot inode, note all the 1277 * blocks that it claims with BLK_SNAP so that fsck will 1278 * be able to account for those blocks properly and so 1279 * that this snapshot knows that it need not copy them 1280 * if the other snapshot holding them is freed. This code 1281 * is reproduced once each for UFS1 and UFS2. 1282 */ 1283 static int 1284 expunge_ufs2(snapvp, cancelip, fs, acctfunc, expungetype, clearmode) 1285 struct vnode *snapvp; 1286 struct inode *cancelip; 1287 struct fs *fs; 1288 int (*acctfunc)(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *, 1289 struct fs *, ufs_lbn_t, int); 1290 int expungetype; 1291 int clearmode; 1292 { 1293 int i, error, indiroff; 1294 ufs_lbn_t lbn, rlbn; 1295 ufs2_daddr_t len, blkno, numblks, blksperindir; 1296 struct ufs2_dinode *dip; 1297 struct thread *td = curthread; 1298 struct buf *bp; 1299 1300 /* 1301 * Prepare to expunge the inode. If its inode block has not 1302 * yet been copied, then allocate and fill the copy. 1303 */ 1304 lbn = fragstoblks(fs, ino_to_fsba(fs, cancelip->i_number)); 1305 blkno = 0; 1306 if (lbn < UFS_NDADDR) { 1307 blkno = VTOI(snapvp)->i_din2->di_db[lbn]; 1308 } else { 1309 if (DOINGSOFTDEP(snapvp)) 1310 softdep_prealloc(snapvp, MNT_WAIT); 1311 td->td_pflags |= TDP_COWINPROGRESS; 1312 error = ffs_balloc_ufs2(snapvp, lblktosize(fs, (off_t)lbn), 1313 fs->fs_bsize, KERNCRED, BA_METAONLY, &bp); 1314 td->td_pflags &= ~TDP_COWINPROGRESS; 1315 if (error) 1316 return (error); 1317 indiroff = (lbn - UFS_NDADDR) % NINDIR(fs); 1318 blkno = ((ufs2_daddr_t *)(bp->b_data))[indiroff]; 1319 bqrelse(bp); 1320 } 1321 if (blkno != 0) { 1322 if ((error = bread(snapvp, lbn, fs->fs_bsize, KERNCRED, &bp))) 1323 return (error); 1324 } else { 1325 error = ffs_balloc_ufs2(snapvp, lblktosize(fs, (off_t)lbn), 1326 fs->fs_bsize, KERNCRED, 0, &bp); 1327 if (error) 1328 return (error); 1329 if ((error = readblock(snapvp, bp, lbn)) != 0) 1330 return (error); 1331 } 1332 /* 1333 * Set a snapshot inode to be a zero length file, regular files 1334 * to be completely unallocated. 1335 */ 1336 dip = (struct ufs2_dinode *)bp->b_data + 1337 ino_to_fsbo(fs, cancelip->i_number); 1338 dip->di_size = 0; 1339 dip->di_blocks = 0; 1340 dip->di_flags &= ~SF_SNAPSHOT; 1341 bzero(&dip->di_db[0], (UFS_NDADDR + UFS_NIADDR) * sizeof(ufs2_daddr_t)); 1342 if (clearmode || cancelip->i_effnlink == 0) 1343 dip->di_mode = 0; 1344 else 1345 ffs_update_dinode_ckhash(fs, dip); 1346 bdwrite(bp); 1347 /* 1348 * Now go through and expunge all the blocks in the file 1349 * using the function requested. 1350 */ 1351 numblks = howmany(cancelip->i_size, fs->fs_bsize); 1352 if ((error = (*acctfunc)(snapvp, &cancelip->i_din2->di_db[0], 1353 &cancelip->i_din2->di_db[UFS_NDADDR], fs, 0, expungetype))) 1354 return (error); 1355 if ((error = (*acctfunc)(snapvp, &cancelip->i_din2->di_ib[0], 1356 &cancelip->i_din2->di_ib[UFS_NIADDR], fs, -1, expungetype))) 1357 return (error); 1358 blksperindir = 1; 1359 lbn = -UFS_NDADDR; 1360 len = numblks - UFS_NDADDR; 1361 rlbn = UFS_NDADDR; 1362 for (i = 0; len > 0 && i < UFS_NIADDR; i++) { 1363 error = indiracct_ufs2(snapvp, ITOV(cancelip), i, 1364 cancelip->i_din2->di_ib[i], lbn, rlbn, len, 1365 blksperindir, fs, acctfunc, expungetype); 1366 if (error) 1367 return (error); 1368 blksperindir *= NINDIR(fs); 1369 lbn -= blksperindir + 1; 1370 len -= blksperindir; 1371 rlbn += blksperindir; 1372 } 1373 return (0); 1374 } 1375 1376 /* 1377 * Descend an indirect block chain for vnode cancelvp accounting for all 1378 * its indirect blocks in snapvp. 1379 */ 1380 static int 1381 indiracct_ufs2(snapvp, cancelvp, level, blkno, lbn, rlbn, remblks, 1382 blksperindir, fs, acctfunc, expungetype) 1383 struct vnode *snapvp; 1384 struct vnode *cancelvp; 1385 int level; 1386 ufs2_daddr_t blkno; 1387 ufs_lbn_t lbn; 1388 ufs_lbn_t rlbn; 1389 ufs_lbn_t remblks; 1390 ufs_lbn_t blksperindir; 1391 struct fs *fs; 1392 int (*acctfunc)(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *, 1393 struct fs *, ufs_lbn_t, int); 1394 int expungetype; 1395 { 1396 int error, num, i; 1397 ufs_lbn_t subblksperindir; 1398 struct indir indirs[UFS_NIADDR + 2]; 1399 ufs2_daddr_t last, *bap; 1400 struct buf *bp; 1401 1402 if (blkno == 0) { 1403 if (expungetype == BLK_NOCOPY) 1404 return (0); 1405 panic("indiracct_ufs2: missing indir"); 1406 } 1407 if ((error = ufs_getlbns(cancelvp, rlbn, indirs, &num)) != 0) 1408 return (error); 1409 if (lbn != indirs[num - 1 - level].in_lbn || num < 2) 1410 panic("indiracct_ufs2: botched params"); 1411 /* 1412 * We have to expand bread here since it will deadlock looking 1413 * up the block number for any blocks that are not in the cache. 1414 */ 1415 bp = getblk(cancelvp, lbn, fs->fs_bsize, 0, 0, 0); 1416 bp->b_blkno = fsbtodb(fs, blkno); 1417 if ((bp->b_flags & B_CACHE) == 0 && 1418 (error = readblock(cancelvp, bp, fragstoblks(fs, blkno)))) { 1419 brelse(bp); 1420 return (error); 1421 } 1422 /* 1423 * Account for the block pointers in this indirect block. 1424 */ 1425 last = howmany(remblks, blksperindir); 1426 if (last > NINDIR(fs)) 1427 last = NINDIR(fs); 1428 bap = malloc(fs->fs_bsize, M_DEVBUF, M_WAITOK); 1429 bcopy(bp->b_data, (caddr_t)bap, fs->fs_bsize); 1430 bqrelse(bp); 1431 error = (*acctfunc)(snapvp, &bap[0], &bap[last], fs, 1432 level == 0 ? rlbn : -1, expungetype); 1433 if (error || level == 0) 1434 goto out; 1435 /* 1436 * Account for the block pointers in each of the indirect blocks 1437 * in the levels below us. 1438 */ 1439 subblksperindir = blksperindir / NINDIR(fs); 1440 for (lbn++, level--, i = 0; i < last; i++) { 1441 error = indiracct_ufs2(snapvp, cancelvp, level, bap[i], lbn, 1442 rlbn, remblks, subblksperindir, fs, acctfunc, expungetype); 1443 if (error) 1444 goto out; 1445 rlbn += blksperindir; 1446 lbn -= blksperindir; 1447 remblks -= blksperindir; 1448 } 1449 out: 1450 free(bap, M_DEVBUF); 1451 return (error); 1452 } 1453 1454 /* 1455 * Do both snap accounting and map accounting. 1456 */ 1457 static int 1458 fullacct_ufs2(vp, oldblkp, lastblkp, fs, lblkno, exptype) 1459 struct vnode *vp; 1460 ufs2_daddr_t *oldblkp, *lastblkp; 1461 struct fs *fs; 1462 ufs_lbn_t lblkno; 1463 int exptype; /* BLK_SNAP or BLK_NOCOPY */ 1464 { 1465 int error; 1466 1467 if ((error = snapacct_ufs2(vp, oldblkp, lastblkp, fs, lblkno, exptype))) 1468 return (error); 1469 return (mapacct_ufs2(vp, oldblkp, lastblkp, fs, lblkno, exptype)); 1470 } 1471 1472 /* 1473 * Identify a set of blocks allocated in a snapshot inode. 1474 */ 1475 static int 1476 snapacct_ufs2(vp, oldblkp, lastblkp, fs, lblkno, expungetype) 1477 struct vnode *vp; 1478 ufs2_daddr_t *oldblkp, *lastblkp; 1479 struct fs *fs; 1480 ufs_lbn_t lblkno; 1481 int expungetype; /* BLK_SNAP or BLK_NOCOPY */ 1482 { 1483 struct inode *ip = VTOI(vp); 1484 ufs2_daddr_t blkno, *blkp; 1485 ufs_lbn_t lbn; 1486 struct buf *ibp; 1487 int error; 1488 1489 for ( ; oldblkp < lastblkp; oldblkp++) { 1490 blkno = *oldblkp; 1491 if (blkno == 0 || blkno == BLK_NOCOPY || blkno == BLK_SNAP) 1492 continue; 1493 lbn = fragstoblks(fs, blkno); 1494 if (lbn < UFS_NDADDR) { 1495 blkp = &ip->i_din2->di_db[lbn]; 1496 ip->i_flag |= IN_CHANGE | IN_UPDATE; 1497 } else { 1498 error = ffs_balloc_ufs2(vp, lblktosize(fs, (off_t)lbn), 1499 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp); 1500 if (error) 1501 return (error); 1502 blkp = &((ufs2_daddr_t *)(ibp->b_data)) 1503 [(lbn - UFS_NDADDR) % NINDIR(fs)]; 1504 } 1505 /* 1506 * If we are expunging a snapshot vnode and we 1507 * find a block marked BLK_NOCOPY, then it is 1508 * one that has been allocated to this snapshot after 1509 * we took our current snapshot and can be ignored. 1510 */ 1511 if (expungetype == BLK_SNAP && *blkp == BLK_NOCOPY) { 1512 if (lbn >= UFS_NDADDR) 1513 brelse(ibp); 1514 } else { 1515 if (*blkp != 0) 1516 panic("snapacct_ufs2: bad block"); 1517 *blkp = expungetype; 1518 if (lbn >= UFS_NDADDR) 1519 bdwrite(ibp); 1520 } 1521 } 1522 return (0); 1523 } 1524 1525 /* 1526 * Account for a set of blocks allocated in a snapshot inode. 1527 */ 1528 static int 1529 mapacct_ufs2(vp, oldblkp, lastblkp, fs, lblkno, expungetype) 1530 struct vnode *vp; 1531 ufs2_daddr_t *oldblkp, *lastblkp; 1532 struct fs *fs; 1533 ufs_lbn_t lblkno; 1534 int expungetype; 1535 { 1536 ufs2_daddr_t blkno; 1537 struct inode *ip; 1538 ino_t inum; 1539 int acctit; 1540 1541 ip = VTOI(vp); 1542 inum = ip->i_number; 1543 if (lblkno == -1) 1544 acctit = 0; 1545 else 1546 acctit = 1; 1547 for ( ; oldblkp < lastblkp; oldblkp++, lblkno++) { 1548 blkno = *oldblkp; 1549 if (blkno == 0 || blkno == BLK_NOCOPY) 1550 continue; 1551 if (acctit && expungetype == BLK_SNAP && blkno != BLK_SNAP) 1552 *ip->i_snapblklist++ = lblkno; 1553 if (blkno == BLK_SNAP) 1554 blkno = blkstofrags(fs, lblkno); 1555 ffs_blkfree(ITOUMP(ip), fs, vp, blkno, fs->fs_bsize, inum, 1556 vp->v_type, NULL, SINGLETON_KEY); 1557 } 1558 return (0); 1559 } 1560 1561 /* 1562 * Decrement extra reference on snapshot when last name is removed. 1563 * It will not be freed until the last open reference goes away. 1564 */ 1565 void 1566 ffs_snapgone(ip) 1567 struct inode *ip; 1568 { 1569 struct inode *xp; 1570 struct fs *fs; 1571 int snaploc; 1572 struct snapdata *sn; 1573 struct ufsmount *ump; 1574 1575 /* 1576 * Find snapshot in incore list. 1577 */ 1578 xp = NULL; 1579 sn = ITODEVVP(ip)->v_rdev->si_snapdata; 1580 if (sn != NULL) 1581 TAILQ_FOREACH(xp, &sn->sn_head, i_nextsnap) 1582 if (xp == ip) 1583 break; 1584 if (xp != NULL) 1585 vrele(ITOV(ip)); 1586 else if (snapdebug) 1587 printf("ffs_snapgone: lost snapshot vnode %ju\n", 1588 (uintmax_t)ip->i_number); 1589 /* 1590 * Delete snapshot inode from superblock. Keep list dense. 1591 */ 1592 ump = ITOUMP(ip); 1593 fs = ump->um_fs; 1594 UFS_LOCK(ump); 1595 for (snaploc = 0; snaploc < FSMAXSNAP; snaploc++) 1596 if (fs->fs_snapinum[snaploc] == ip->i_number) 1597 break; 1598 if (snaploc < FSMAXSNAP) { 1599 for (snaploc++; snaploc < FSMAXSNAP; snaploc++) { 1600 if (fs->fs_snapinum[snaploc] == 0) 1601 break; 1602 fs->fs_snapinum[snaploc - 1] = fs->fs_snapinum[snaploc]; 1603 } 1604 fs->fs_snapinum[snaploc - 1] = 0; 1605 } 1606 UFS_UNLOCK(ump); 1607 } 1608 1609 /* 1610 * Prepare a snapshot file for being removed. 1611 */ 1612 void 1613 ffs_snapremove(vp) 1614 struct vnode *vp; 1615 { 1616 struct inode *ip; 1617 struct vnode *devvp; 1618 struct buf *ibp; 1619 struct fs *fs; 1620 ufs2_daddr_t numblks, blkno, dblk; 1621 int error, i, last, loc; 1622 struct snapdata *sn; 1623 1624 ip = VTOI(vp); 1625 fs = ITOFS(ip); 1626 devvp = ITODEVVP(ip); 1627 /* 1628 * If active, delete from incore list (this snapshot may 1629 * already have been in the process of being deleted, so 1630 * would not have been active). 1631 * 1632 * Clear copy-on-write flag if last snapshot. 1633 */ 1634 VI_LOCK(devvp); 1635 if (ip->i_nextsnap.tqe_prev != 0) { 1636 sn = devvp->v_rdev->si_snapdata; 1637 TAILQ_REMOVE(&sn->sn_head, ip, i_nextsnap); 1638 ip->i_nextsnap.tqe_prev = 0; 1639 VI_UNLOCK(devvp); 1640 lockmgr(&vp->v_lock, LK_EXCLUSIVE, NULL); 1641 for (i = 0; i < sn->sn_lock.lk_recurse; i++) 1642 lockmgr(&vp->v_lock, LK_EXCLUSIVE, NULL); 1643 KASSERT(vp->v_vnlock == &sn->sn_lock, 1644 ("ffs_snapremove: lost lock mutation")); 1645 vp->v_vnlock = &vp->v_lock; 1646 VI_LOCK(devvp); 1647 while (sn->sn_lock.lk_recurse > 0) 1648 lockmgr(&sn->sn_lock, LK_RELEASE, NULL); 1649 lockmgr(&sn->sn_lock, LK_RELEASE, NULL); 1650 try_free_snapdata(devvp); 1651 } else 1652 VI_UNLOCK(devvp); 1653 /* 1654 * Clear all BLK_NOCOPY fields. Pass any block claims to other 1655 * snapshots that want them (see ffs_snapblkfree below). 1656 */ 1657 for (blkno = 1; blkno < UFS_NDADDR; blkno++) { 1658 dblk = DIP(ip, i_db[blkno]); 1659 if (dblk == 0) 1660 continue; 1661 if (dblk == BLK_NOCOPY || dblk == BLK_SNAP) 1662 DIP_SET(ip, i_db[blkno], 0); 1663 else if ((dblk == blkstofrags(fs, blkno) && 1664 ffs_snapblkfree(fs, ITODEVVP(ip), dblk, fs->fs_bsize, 1665 ip->i_number, vp->v_type, NULL))) { 1666 DIP_SET(ip, i_blocks, DIP(ip, i_blocks) - 1667 btodb(fs->fs_bsize)); 1668 DIP_SET(ip, i_db[blkno], 0); 1669 } 1670 } 1671 numblks = howmany(ip->i_size, fs->fs_bsize); 1672 for (blkno = UFS_NDADDR; blkno < numblks; blkno += NINDIR(fs)) { 1673 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)blkno), 1674 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp); 1675 if (error) 1676 continue; 1677 if (fs->fs_size - blkno > NINDIR(fs)) 1678 last = NINDIR(fs); 1679 else 1680 last = fs->fs_size - blkno; 1681 for (loc = 0; loc < last; loc++) { 1682 if (I_IS_UFS1(ip)) { 1683 dblk = ((ufs1_daddr_t *)(ibp->b_data))[loc]; 1684 if (dblk == 0) 1685 continue; 1686 if (dblk == BLK_NOCOPY || dblk == BLK_SNAP) 1687 ((ufs1_daddr_t *)(ibp->b_data))[loc]= 0; 1688 else if ((dblk == blkstofrags(fs, blkno) && 1689 ffs_snapblkfree(fs, ITODEVVP(ip), dblk, 1690 fs->fs_bsize, ip->i_number, vp->v_type, 1691 NULL))) { 1692 ip->i_din1->di_blocks -= 1693 btodb(fs->fs_bsize); 1694 ((ufs1_daddr_t *)(ibp->b_data))[loc]= 0; 1695 } 1696 continue; 1697 } 1698 dblk = ((ufs2_daddr_t *)(ibp->b_data))[loc]; 1699 if (dblk == 0) 1700 continue; 1701 if (dblk == BLK_NOCOPY || dblk == BLK_SNAP) 1702 ((ufs2_daddr_t *)(ibp->b_data))[loc] = 0; 1703 else if ((dblk == blkstofrags(fs, blkno) && 1704 ffs_snapblkfree(fs, ITODEVVP(ip), dblk, 1705 fs->fs_bsize, ip->i_number, vp->v_type, NULL))) { 1706 ip->i_din2->di_blocks -= btodb(fs->fs_bsize); 1707 ((ufs2_daddr_t *)(ibp->b_data))[loc] = 0; 1708 } 1709 } 1710 bawrite(ibp); 1711 } 1712 /* 1713 * Clear snapshot flag and drop reference. 1714 */ 1715 ip->i_flags &= ~SF_SNAPSHOT; 1716 DIP_SET(ip, i_flags, ip->i_flags); 1717 ip->i_flag |= IN_CHANGE | IN_UPDATE; 1718 /* 1719 * The dirtied indirects must be written out before 1720 * softdep_setup_freeblocks() is called. Otherwise indir_trunc() 1721 * may find indirect pointers using the magic BLK_* values. 1722 */ 1723 if (DOINGSOFTDEP(vp)) 1724 ffs_syncvnode(vp, MNT_WAIT, 0); 1725 #ifdef QUOTA 1726 /* 1727 * Reenable disk quotas for ex-snapshot file. 1728 */ 1729 if (!getinoquota(ip)) 1730 (void) chkdq(ip, DIP(ip, i_blocks), KERNCRED, FORCE); 1731 #endif 1732 } 1733 1734 /* 1735 * Notification that a block is being freed. Return zero if the free 1736 * should be allowed to proceed. Return non-zero if the snapshot file 1737 * wants to claim the block. The block will be claimed if it is an 1738 * uncopied part of one of the snapshots. It will be freed if it is 1739 * either a BLK_NOCOPY or has already been copied in all of the snapshots. 1740 * If a fragment is being freed, then all snapshots that care about 1741 * it must make a copy since a snapshot file can only claim full sized 1742 * blocks. Note that if more than one snapshot file maps the block, 1743 * we can pick one at random to claim it. Since none of the snapshots 1744 * can change, we are assurred that they will all see the same unmodified 1745 * image. When deleting a snapshot file (see ffs_snapremove above), we 1746 * must push any of these claimed blocks to one of the other snapshots 1747 * that maps it. These claimed blocks are easily identified as they will 1748 * have a block number equal to their logical block number within the 1749 * snapshot. A copied block can never have this property because they 1750 * must always have been allocated from a BLK_NOCOPY location. 1751 */ 1752 int 1753 ffs_snapblkfree(fs, devvp, bno, size, inum, vtype, wkhd) 1754 struct fs *fs; 1755 struct vnode *devvp; 1756 ufs2_daddr_t bno; 1757 long size; 1758 ino_t inum; 1759 enum vtype vtype; 1760 struct workhead *wkhd; 1761 { 1762 struct buf *ibp, *cbp, *savedcbp = NULL; 1763 struct thread *td = curthread; 1764 struct inode *ip; 1765 struct vnode *vp = NULL; 1766 ufs_lbn_t lbn; 1767 ufs2_daddr_t blkno; 1768 int indiroff = 0, error = 0, claimedblk = 0; 1769 struct snapdata *sn; 1770 1771 lbn = fragstoblks(fs, bno); 1772 retry: 1773 VI_LOCK(devvp); 1774 sn = devvp->v_rdev->si_snapdata; 1775 if (sn == NULL) { 1776 VI_UNLOCK(devvp); 1777 return (0); 1778 } 1779 if (lockmgr(&sn->sn_lock, LK_INTERLOCK | LK_EXCLUSIVE | LK_SLEEPFAIL, 1780 VI_MTX(devvp)) != 0) 1781 goto retry; 1782 TAILQ_FOREACH(ip, &sn->sn_head, i_nextsnap) { 1783 vp = ITOV(ip); 1784 if (DOINGSOFTDEP(vp)) 1785 softdep_prealloc(vp, MNT_WAIT); 1786 /* 1787 * Lookup block being written. 1788 */ 1789 if (lbn < UFS_NDADDR) { 1790 blkno = DIP(ip, i_db[lbn]); 1791 } else { 1792 td->td_pflags |= TDP_COWINPROGRESS; 1793 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)lbn), 1794 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp); 1795 td->td_pflags &= ~TDP_COWINPROGRESS; 1796 if (error) 1797 break; 1798 indiroff = (lbn - UFS_NDADDR) % NINDIR(fs); 1799 if (I_IS_UFS1(ip)) 1800 blkno=((ufs1_daddr_t *)(ibp->b_data))[indiroff]; 1801 else 1802 blkno=((ufs2_daddr_t *)(ibp->b_data))[indiroff]; 1803 } 1804 /* 1805 * Check to see if block needs to be copied. 1806 */ 1807 if (blkno == 0) { 1808 /* 1809 * A block that we map is being freed. If it has not 1810 * been claimed yet, we will claim or copy it (below). 1811 */ 1812 claimedblk = 1; 1813 } else if (blkno == BLK_SNAP) { 1814 /* 1815 * No previous snapshot claimed the block, 1816 * so it will be freed and become a BLK_NOCOPY 1817 * (don't care) for us. 1818 */ 1819 if (claimedblk) 1820 panic("snapblkfree: inconsistent block type"); 1821 if (lbn < UFS_NDADDR) { 1822 DIP_SET(ip, i_db[lbn], BLK_NOCOPY); 1823 ip->i_flag |= IN_CHANGE | IN_UPDATE; 1824 } else if (I_IS_UFS1(ip)) { 1825 ((ufs1_daddr_t *)(ibp->b_data))[indiroff] = 1826 BLK_NOCOPY; 1827 bdwrite(ibp); 1828 } else { 1829 ((ufs2_daddr_t *)(ibp->b_data))[indiroff] = 1830 BLK_NOCOPY; 1831 bdwrite(ibp); 1832 } 1833 continue; 1834 } else /* BLK_NOCOPY or default */ { 1835 /* 1836 * If the snapshot has already copied the block 1837 * (default), or does not care about the block, 1838 * it is not needed. 1839 */ 1840 if (lbn >= UFS_NDADDR) 1841 bqrelse(ibp); 1842 continue; 1843 } 1844 /* 1845 * If this is a full size block, we will just grab it 1846 * and assign it to the snapshot inode. Otherwise we 1847 * will proceed to copy it. See explanation for this 1848 * routine as to why only a single snapshot needs to 1849 * claim this block. 1850 */ 1851 if (size == fs->fs_bsize) { 1852 #ifdef DEBUG 1853 if (snapdebug) 1854 printf("%s %ju lbn %jd from inum %ju\n", 1855 "Grabonremove: snapino", 1856 (uintmax_t)ip->i_number, 1857 (intmax_t)lbn, (uintmax_t)inum); 1858 #endif 1859 /* 1860 * If journaling is tracking this write we must add 1861 * the work to the inode or indirect being written. 1862 */ 1863 if (wkhd != NULL) { 1864 if (lbn < UFS_NDADDR) 1865 softdep_inode_append(ip, 1866 curthread->td_ucred, wkhd); 1867 else 1868 softdep_buf_append(ibp, wkhd); 1869 } 1870 if (lbn < UFS_NDADDR) { 1871 DIP_SET(ip, i_db[lbn], bno); 1872 } else if (I_IS_UFS1(ip)) { 1873 ((ufs1_daddr_t *)(ibp->b_data))[indiroff] = bno; 1874 bdwrite(ibp); 1875 } else { 1876 ((ufs2_daddr_t *)(ibp->b_data))[indiroff] = bno; 1877 bdwrite(ibp); 1878 } 1879 DIP_SET(ip, i_blocks, DIP(ip, i_blocks) + btodb(size)); 1880 ip->i_flag |= IN_CHANGE | IN_UPDATE; 1881 lockmgr(vp->v_vnlock, LK_RELEASE, NULL); 1882 return (1); 1883 } 1884 if (lbn >= UFS_NDADDR) 1885 bqrelse(ibp); 1886 /* 1887 * Allocate the block into which to do the copy. Note that this 1888 * allocation will never require any additional allocations for 1889 * the snapshot inode. 1890 */ 1891 td->td_pflags |= TDP_COWINPROGRESS; 1892 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)lbn), 1893 fs->fs_bsize, KERNCRED, 0, &cbp); 1894 td->td_pflags &= ~TDP_COWINPROGRESS; 1895 if (error) 1896 break; 1897 #ifdef DEBUG 1898 if (snapdebug) 1899 printf("%s%ju lbn %jd %s %ju size %ld to blkno %jd\n", 1900 "Copyonremove: snapino ", (uintmax_t)ip->i_number, 1901 (intmax_t)lbn, "for inum", (uintmax_t)inum, size, 1902 (intmax_t)cbp->b_blkno); 1903 #endif 1904 /* 1905 * If we have already read the old block contents, then 1906 * simply copy them to the new block. Note that we need 1907 * to synchronously write snapshots that have not been 1908 * unlinked, and hence will be visible after a crash, 1909 * to ensure their integrity. At a minimum we ensure the 1910 * integrity of the filesystem metadata, but use the 1911 * dopersistence sysctl-setable flag to decide on the 1912 * persistence needed for file content data. 1913 */ 1914 if (savedcbp != NULL) { 1915 bcopy(savedcbp->b_data, cbp->b_data, fs->fs_bsize); 1916 bawrite(cbp); 1917 if ((vtype == VDIR || dopersistence) && 1918 ip->i_effnlink > 0) 1919 (void) ffs_syncvnode(vp, MNT_WAIT, NO_INO_UPDT); 1920 continue; 1921 } 1922 /* 1923 * Otherwise, read the old block contents into the buffer. 1924 */ 1925 if ((error = readblock(vp, cbp, lbn)) != 0) { 1926 bzero(cbp->b_data, fs->fs_bsize); 1927 bawrite(cbp); 1928 if ((vtype == VDIR || dopersistence) && 1929 ip->i_effnlink > 0) 1930 (void) ffs_syncvnode(vp, MNT_WAIT, NO_INO_UPDT); 1931 break; 1932 } 1933 savedcbp = cbp; 1934 } 1935 /* 1936 * Note that we need to synchronously write snapshots that 1937 * have not been unlinked, and hence will be visible after 1938 * a crash, to ensure their integrity. At a minimum we 1939 * ensure the integrity of the filesystem metadata, but 1940 * use the dopersistence sysctl-setable flag to decide on 1941 * the persistence needed for file content data. 1942 */ 1943 if (savedcbp) { 1944 vp = savedcbp->b_vp; 1945 bawrite(savedcbp); 1946 if ((vtype == VDIR || dopersistence) && 1947 VTOI(vp)->i_effnlink > 0) 1948 (void) ffs_syncvnode(vp, MNT_WAIT, NO_INO_UPDT); 1949 } 1950 /* 1951 * If we have been unable to allocate a block in which to do 1952 * the copy, then return non-zero so that the fragment will 1953 * not be freed. Although space will be lost, the snapshot 1954 * will stay consistent. 1955 */ 1956 if (error != 0 && wkhd != NULL) 1957 softdep_freework(wkhd); 1958 lockmgr(&sn->sn_lock, LK_RELEASE, NULL); 1959 return (error); 1960 } 1961 1962 /* 1963 * Associate snapshot files when mounting. 1964 */ 1965 void 1966 ffs_snapshot_mount(mp) 1967 struct mount *mp; 1968 { 1969 struct ufsmount *ump = VFSTOUFS(mp); 1970 struct vnode *devvp = ump->um_devvp; 1971 struct fs *fs = ump->um_fs; 1972 struct thread *td = curthread; 1973 struct snapdata *sn; 1974 struct vnode *vp; 1975 struct vnode *lastvp; 1976 struct inode *ip; 1977 struct uio auio; 1978 struct iovec aiov; 1979 void *snapblklist; 1980 char *reason; 1981 daddr_t snaplistsize; 1982 int error, snaploc, loc; 1983 1984 /* 1985 * XXX The following needs to be set before ffs_truncate or 1986 * VOP_READ can be called. 1987 */ 1988 mp->mnt_stat.f_iosize = fs->fs_bsize; 1989 /* 1990 * Process each snapshot listed in the superblock. 1991 */ 1992 vp = NULL; 1993 lastvp = NULL; 1994 sn = NULL; 1995 for (snaploc = 0; snaploc < FSMAXSNAP; snaploc++) { 1996 if (fs->fs_snapinum[snaploc] == 0) 1997 break; 1998 if ((error = ffs_vget(mp, fs->fs_snapinum[snaploc], 1999 LK_EXCLUSIVE, &vp)) != 0){ 2000 printf("ffs_snapshot_mount: vget failed %d\n", error); 2001 continue; 2002 } 2003 ip = VTOI(vp); 2004 if (vp->v_type != VREG) { 2005 reason = "non-file snapshot"; 2006 } else if (!IS_SNAPSHOT(ip)) { 2007 reason = "non-snapshot"; 2008 } else if (ip->i_size == 2009 lblktosize(fs, howmany(fs->fs_size, fs->fs_frag))) { 2010 reason = "old format snapshot"; 2011 (void)ffs_truncate(vp, (off_t)0, 0, NOCRED); 2012 (void)ffs_syncvnode(vp, MNT_WAIT, 0); 2013 } else { 2014 reason = NULL; 2015 } 2016 if (reason != NULL) { 2017 printf("ffs_snapshot_mount: %s inode %d\n", 2018 reason, fs->fs_snapinum[snaploc]); 2019 vput(vp); 2020 vp = NULL; 2021 for (loc = snaploc + 1; loc < FSMAXSNAP; loc++) { 2022 if (fs->fs_snapinum[loc] == 0) 2023 break; 2024 fs->fs_snapinum[loc - 1] = fs->fs_snapinum[loc]; 2025 } 2026 fs->fs_snapinum[loc - 1] = 0; 2027 snaploc--; 2028 continue; 2029 } 2030 /* 2031 * Acquire a lock on the snapdata structure, creating it if 2032 * necessary. 2033 */ 2034 sn = ffs_snapdata_acquire(devvp); 2035 /* 2036 * Change vnode to use shared snapshot lock instead of the 2037 * original private lock. 2038 */ 2039 vp->v_vnlock = &sn->sn_lock; 2040 lockmgr(&vp->v_lock, LK_RELEASE, NULL); 2041 /* 2042 * Link it onto the active snapshot list. 2043 */ 2044 VI_LOCK(devvp); 2045 if (ip->i_nextsnap.tqe_prev != 0) 2046 panic("ffs_snapshot_mount: %ju already on list", 2047 (uintmax_t)ip->i_number); 2048 else 2049 TAILQ_INSERT_TAIL(&sn->sn_head, ip, i_nextsnap); 2050 vp->v_vflag |= VV_SYSTEM; 2051 VI_UNLOCK(devvp); 2052 VOP_UNLOCK(vp, 0); 2053 lastvp = vp; 2054 } 2055 vp = lastvp; 2056 /* 2057 * No usable snapshots found. 2058 */ 2059 if (sn == NULL || vp == NULL) 2060 return; 2061 /* 2062 * Allocate the space for the block hints list. We always want to 2063 * use the list from the newest snapshot. 2064 */ 2065 auio.uio_iov = &aiov; 2066 auio.uio_iovcnt = 1; 2067 aiov.iov_base = (void *)&snaplistsize; 2068 aiov.iov_len = sizeof(snaplistsize); 2069 auio.uio_resid = aiov.iov_len; 2070 auio.uio_offset = 2071 lblktosize(fs, howmany(fs->fs_size, fs->fs_frag)); 2072 auio.uio_segflg = UIO_SYSSPACE; 2073 auio.uio_rw = UIO_READ; 2074 auio.uio_td = td; 2075 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2076 if ((error = VOP_READ(vp, &auio, IO_UNIT, td->td_ucred)) != 0) { 2077 printf("ffs_snapshot_mount: read_1 failed %d\n", error); 2078 VOP_UNLOCK(vp, 0); 2079 return; 2080 } 2081 snapblklist = malloc(snaplistsize * sizeof(daddr_t), 2082 M_UFSMNT, M_WAITOK); 2083 auio.uio_iovcnt = 1; 2084 aiov.iov_base = snapblklist; 2085 aiov.iov_len = snaplistsize * sizeof (daddr_t); 2086 auio.uio_resid = aiov.iov_len; 2087 auio.uio_offset -= sizeof(snaplistsize); 2088 if ((error = VOP_READ(vp, &auio, IO_UNIT, td->td_ucred)) != 0) { 2089 printf("ffs_snapshot_mount: read_2 failed %d\n", error); 2090 VOP_UNLOCK(vp, 0); 2091 free(snapblklist, M_UFSMNT); 2092 return; 2093 } 2094 VOP_UNLOCK(vp, 0); 2095 VI_LOCK(devvp); 2096 ASSERT_VOP_LOCKED(devvp, "ffs_snapshot_mount"); 2097 sn->sn_listsize = snaplistsize; 2098 sn->sn_blklist = (daddr_t *)snapblklist; 2099 devvp->v_vflag |= VV_COPYONWRITE; 2100 VI_UNLOCK(devvp); 2101 } 2102 2103 /* 2104 * Disassociate snapshot files when unmounting. 2105 */ 2106 void 2107 ffs_snapshot_unmount(mp) 2108 struct mount *mp; 2109 { 2110 struct vnode *devvp = VFSTOUFS(mp)->um_devvp; 2111 struct snapdata *sn; 2112 struct inode *xp; 2113 struct vnode *vp; 2114 2115 VI_LOCK(devvp); 2116 sn = devvp->v_rdev->si_snapdata; 2117 while (sn != NULL && (xp = TAILQ_FIRST(&sn->sn_head)) != NULL) { 2118 vp = ITOV(xp); 2119 TAILQ_REMOVE(&sn->sn_head, xp, i_nextsnap); 2120 xp->i_nextsnap.tqe_prev = 0; 2121 lockmgr(&sn->sn_lock, LK_INTERLOCK | LK_EXCLUSIVE, 2122 VI_MTX(devvp)); 2123 lockmgr(&vp->v_lock, LK_EXCLUSIVE, NULL); 2124 KASSERT(vp->v_vnlock == &sn->sn_lock, 2125 ("ffs_snapshot_unmount: lost lock mutation")); 2126 vp->v_vnlock = &vp->v_lock; 2127 lockmgr(&vp->v_lock, LK_RELEASE, NULL); 2128 lockmgr(&sn->sn_lock, LK_RELEASE, NULL); 2129 if (xp->i_effnlink > 0) 2130 vrele(vp); 2131 VI_LOCK(devvp); 2132 sn = devvp->v_rdev->si_snapdata; 2133 } 2134 try_free_snapdata(devvp); 2135 ASSERT_VOP_LOCKED(devvp, "ffs_snapshot_unmount"); 2136 } 2137 2138 /* 2139 * Check the buffer block to be belong to device buffer that shall be 2140 * locked after snaplk. devvp shall be locked on entry, and will be 2141 * leaved locked upon exit. 2142 */ 2143 static int 2144 ffs_bp_snapblk(devvp, bp) 2145 struct vnode *devvp; 2146 struct buf *bp; 2147 { 2148 struct snapdata *sn; 2149 struct fs *fs; 2150 ufs2_daddr_t lbn, *snapblklist; 2151 int lower, upper, mid; 2152 2153 ASSERT_VI_LOCKED(devvp, "ffs_bp_snapblk"); 2154 KASSERT(devvp->v_type == VCHR, ("Not a device %p", devvp)); 2155 sn = devvp->v_rdev->si_snapdata; 2156 if (sn == NULL || TAILQ_FIRST(&sn->sn_head) == NULL) 2157 return (0); 2158 fs = ITOFS(TAILQ_FIRST(&sn->sn_head)); 2159 lbn = fragstoblks(fs, dbtofsb(fs, bp->b_blkno)); 2160 snapblklist = sn->sn_blklist; 2161 upper = sn->sn_listsize - 1; 2162 lower = 1; 2163 while (lower <= upper) { 2164 mid = (lower + upper) / 2; 2165 if (snapblklist[mid] == lbn) 2166 break; 2167 if (snapblklist[mid] < lbn) 2168 lower = mid + 1; 2169 else 2170 upper = mid - 1; 2171 } 2172 if (lower <= upper) 2173 return (1); 2174 return (0); 2175 } 2176 2177 void 2178 ffs_bdflush(bo, bp) 2179 struct bufobj *bo; 2180 struct buf *bp; 2181 { 2182 struct thread *td; 2183 struct vnode *vp, *devvp; 2184 struct buf *nbp; 2185 int bp_bdskip; 2186 2187 if (bo->bo_dirty.bv_cnt <= dirtybufthresh) 2188 return; 2189 2190 td = curthread; 2191 vp = bp->b_vp; 2192 devvp = bo2vnode(bo); 2193 KASSERT(vp == devvp, ("devvp != vp %p %p", bo, bp)); 2194 2195 VI_LOCK(devvp); 2196 bp_bdskip = ffs_bp_snapblk(devvp, bp); 2197 if (bp_bdskip) 2198 bdwriteskip++; 2199 VI_UNLOCK(devvp); 2200 if (bo->bo_dirty.bv_cnt > dirtybufthresh + 10 && !bp_bdskip) { 2201 (void) VOP_FSYNC(vp, MNT_NOWAIT, td); 2202 altbufferflushes++; 2203 } else { 2204 BO_LOCK(bo); 2205 /* 2206 * Try to find a buffer to flush. 2207 */ 2208 TAILQ_FOREACH(nbp, &bo->bo_dirty.bv_hd, b_bobufs) { 2209 if ((nbp->b_vflags & BV_BKGRDINPROG) || 2210 BUF_LOCK(nbp, 2211 LK_EXCLUSIVE | LK_NOWAIT, NULL)) 2212 continue; 2213 if (bp == nbp) 2214 panic("bdwrite: found ourselves"); 2215 BO_UNLOCK(bo); 2216 /* 2217 * Don't countdeps with the bo lock 2218 * held. 2219 */ 2220 if (buf_countdeps(nbp, 0)) { 2221 BO_LOCK(bo); 2222 BUF_UNLOCK(nbp); 2223 continue; 2224 } 2225 if (bp_bdskip) { 2226 VI_LOCK(devvp); 2227 if (!ffs_bp_snapblk(vp, nbp)) { 2228 VI_UNLOCK(devvp); 2229 BO_LOCK(bo); 2230 BUF_UNLOCK(nbp); 2231 continue; 2232 } 2233 VI_UNLOCK(devvp); 2234 } 2235 if (nbp->b_flags & B_CLUSTEROK) { 2236 vfs_bio_awrite(nbp); 2237 } else { 2238 bremfree(nbp); 2239 bawrite(nbp); 2240 } 2241 dirtybufferflushes++; 2242 break; 2243 } 2244 if (nbp == NULL) 2245 BO_UNLOCK(bo); 2246 } 2247 } 2248 2249 /* 2250 * Check for need to copy block that is about to be written, 2251 * copying the block if necessary. 2252 */ 2253 int 2254 ffs_copyonwrite(devvp, bp) 2255 struct vnode *devvp; 2256 struct buf *bp; 2257 { 2258 struct snapdata *sn; 2259 struct buf *ibp, *cbp, *savedcbp = NULL; 2260 struct thread *td = curthread; 2261 struct fs *fs; 2262 struct inode *ip; 2263 struct vnode *vp = NULL; 2264 ufs2_daddr_t lbn, blkno, *snapblklist; 2265 int lower, upper, mid, indiroff, error = 0; 2266 int launched_async_io, prev_norunningbuf; 2267 long saved_runningbufspace; 2268 2269 if (devvp != bp->b_vp && IS_SNAPSHOT(VTOI(bp->b_vp))) 2270 return (0); /* Update on a snapshot file */ 2271 if (td->td_pflags & TDP_COWINPROGRESS) 2272 panic("ffs_copyonwrite: recursive call"); 2273 /* 2274 * First check to see if it is in the preallocated list. 2275 * By doing this check we avoid several potential deadlocks. 2276 */ 2277 VI_LOCK(devvp); 2278 sn = devvp->v_rdev->si_snapdata; 2279 if (sn == NULL || 2280 TAILQ_EMPTY(&sn->sn_head)) { 2281 VI_UNLOCK(devvp); 2282 return (0); /* No snapshot */ 2283 } 2284 ip = TAILQ_FIRST(&sn->sn_head); 2285 fs = ITOFS(ip); 2286 lbn = fragstoblks(fs, dbtofsb(fs, bp->b_blkno)); 2287 snapblklist = sn->sn_blklist; 2288 upper = sn->sn_listsize - 1; 2289 lower = 1; 2290 while (lower <= upper) { 2291 mid = (lower + upper) / 2; 2292 if (snapblklist[mid] == lbn) 2293 break; 2294 if (snapblklist[mid] < lbn) 2295 lower = mid + 1; 2296 else 2297 upper = mid - 1; 2298 } 2299 if (lower <= upper) { 2300 VI_UNLOCK(devvp); 2301 return (0); 2302 } 2303 launched_async_io = 0; 2304 prev_norunningbuf = td->td_pflags & TDP_NORUNNINGBUF; 2305 /* 2306 * Since I/O on bp isn't yet in progress and it may be blocked 2307 * for a long time waiting on snaplk, back it out of 2308 * runningbufspace, possibly waking other threads waiting for space. 2309 */ 2310 saved_runningbufspace = bp->b_runningbufspace; 2311 if (saved_runningbufspace != 0) 2312 runningbufwakeup(bp); 2313 /* 2314 * Not in the precomputed list, so check the snapshots. 2315 */ 2316 while (lockmgr(&sn->sn_lock, LK_INTERLOCK | LK_EXCLUSIVE | LK_SLEEPFAIL, 2317 VI_MTX(devvp)) != 0) { 2318 VI_LOCK(devvp); 2319 sn = devvp->v_rdev->si_snapdata; 2320 if (sn == NULL || 2321 TAILQ_EMPTY(&sn->sn_head)) { 2322 VI_UNLOCK(devvp); 2323 if (saved_runningbufspace != 0) { 2324 bp->b_runningbufspace = saved_runningbufspace; 2325 atomic_add_long(&runningbufspace, 2326 bp->b_runningbufspace); 2327 } 2328 return (0); /* Snapshot gone */ 2329 } 2330 } 2331 TAILQ_FOREACH(ip, &sn->sn_head, i_nextsnap) { 2332 vp = ITOV(ip); 2333 if (DOINGSOFTDEP(vp)) 2334 softdep_prealloc(vp, MNT_WAIT); 2335 /* 2336 * We ensure that everything of our own that needs to be 2337 * copied will be done at the time that ffs_snapshot is 2338 * called. Thus we can skip the check here which can 2339 * deadlock in doing the lookup in UFS_BALLOC. 2340 */ 2341 if (bp->b_vp == vp) 2342 continue; 2343 /* 2344 * Check to see if block needs to be copied. We do not have 2345 * to hold the snapshot lock while doing this lookup as it 2346 * will never require any additional allocations for the 2347 * snapshot inode. 2348 */ 2349 if (lbn < UFS_NDADDR) { 2350 blkno = DIP(ip, i_db[lbn]); 2351 } else { 2352 td->td_pflags |= TDP_COWINPROGRESS | TDP_NORUNNINGBUF; 2353 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)lbn), 2354 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp); 2355 td->td_pflags &= ~TDP_COWINPROGRESS; 2356 if (error) 2357 break; 2358 indiroff = (lbn - UFS_NDADDR) % NINDIR(fs); 2359 if (I_IS_UFS1(ip)) 2360 blkno=((ufs1_daddr_t *)(ibp->b_data))[indiroff]; 2361 else 2362 blkno=((ufs2_daddr_t *)(ibp->b_data))[indiroff]; 2363 bqrelse(ibp); 2364 } 2365 #ifdef INVARIANTS 2366 if (blkno == BLK_SNAP && bp->b_lblkno >= 0) 2367 panic("ffs_copyonwrite: bad copy block"); 2368 #endif 2369 if (blkno != 0) 2370 continue; 2371 /* 2372 * Allocate the block into which to do the copy. Since 2373 * multiple processes may all try to copy the same block, 2374 * we have to recheck our need to do a copy if we sleep 2375 * waiting for the lock. 2376 * 2377 * Because all snapshots on a filesystem share a single 2378 * lock, we ensure that we will never be in competition 2379 * with another process to allocate a block. 2380 */ 2381 td->td_pflags |= TDP_COWINPROGRESS | TDP_NORUNNINGBUF; 2382 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)lbn), 2383 fs->fs_bsize, KERNCRED, 0, &cbp); 2384 td->td_pflags &= ~TDP_COWINPROGRESS; 2385 if (error) 2386 break; 2387 #ifdef DEBUG 2388 if (snapdebug) { 2389 printf("Copyonwrite: snapino %ju lbn %jd for ", 2390 (uintmax_t)ip->i_number, (intmax_t)lbn); 2391 if (bp->b_vp == devvp) 2392 printf("fs metadata"); 2393 else 2394 printf("inum %ju", 2395 (uintmax_t)VTOI(bp->b_vp)->i_number); 2396 printf(" lblkno %jd to blkno %jd\n", 2397 (intmax_t)bp->b_lblkno, (intmax_t)cbp->b_blkno); 2398 } 2399 #endif 2400 /* 2401 * If we have already read the old block contents, then 2402 * simply copy them to the new block. Note that we need 2403 * to synchronously write snapshots that have not been 2404 * unlinked, and hence will be visible after a crash, 2405 * to ensure their integrity. At a minimum we ensure the 2406 * integrity of the filesystem metadata, but use the 2407 * dopersistence sysctl-setable flag to decide on the 2408 * persistence needed for file content data. 2409 */ 2410 if (savedcbp != NULL) { 2411 bcopy(savedcbp->b_data, cbp->b_data, fs->fs_bsize); 2412 bawrite(cbp); 2413 if ((devvp == bp->b_vp || bp->b_vp->v_type == VDIR || 2414 dopersistence) && ip->i_effnlink > 0) 2415 (void) ffs_syncvnode(vp, MNT_WAIT, NO_INO_UPDT); 2416 else 2417 launched_async_io = 1; 2418 continue; 2419 } 2420 /* 2421 * Otherwise, read the old block contents into the buffer. 2422 */ 2423 if ((error = readblock(vp, cbp, lbn)) != 0) { 2424 bzero(cbp->b_data, fs->fs_bsize); 2425 bawrite(cbp); 2426 if ((devvp == bp->b_vp || bp->b_vp->v_type == VDIR || 2427 dopersistence) && ip->i_effnlink > 0) 2428 (void) ffs_syncvnode(vp, MNT_WAIT, NO_INO_UPDT); 2429 else 2430 launched_async_io = 1; 2431 break; 2432 } 2433 savedcbp = cbp; 2434 } 2435 /* 2436 * Note that we need to synchronously write snapshots that 2437 * have not been unlinked, and hence will be visible after 2438 * a crash, to ensure their integrity. At a minimum we 2439 * ensure the integrity of the filesystem metadata, but 2440 * use the dopersistence sysctl-setable flag to decide on 2441 * the persistence needed for file content data. 2442 */ 2443 if (savedcbp) { 2444 vp = savedcbp->b_vp; 2445 bawrite(savedcbp); 2446 if ((devvp == bp->b_vp || bp->b_vp->v_type == VDIR || 2447 dopersistence) && VTOI(vp)->i_effnlink > 0) 2448 (void) ffs_syncvnode(vp, MNT_WAIT, NO_INO_UPDT); 2449 else 2450 launched_async_io = 1; 2451 } 2452 lockmgr(vp->v_vnlock, LK_RELEASE, NULL); 2453 td->td_pflags = (td->td_pflags & ~TDP_NORUNNINGBUF) | 2454 prev_norunningbuf; 2455 if (launched_async_io && (td->td_pflags & TDP_NORUNNINGBUF) == 0) 2456 waitrunningbufspace(); 2457 /* 2458 * I/O on bp will now be started, so count it in runningbufspace. 2459 */ 2460 if (saved_runningbufspace != 0) { 2461 bp->b_runningbufspace = saved_runningbufspace; 2462 atomic_add_long(&runningbufspace, bp->b_runningbufspace); 2463 } 2464 return (error); 2465 } 2466 2467 /* 2468 * sync snapshots to force freework records waiting on snapshots to claim 2469 * blocks to free. 2470 */ 2471 void 2472 ffs_sync_snap(mp, waitfor) 2473 struct mount *mp; 2474 int waitfor; 2475 { 2476 struct snapdata *sn; 2477 struct vnode *devvp; 2478 struct vnode *vp; 2479 struct inode *ip; 2480 2481 devvp = VFSTOUFS(mp)->um_devvp; 2482 if ((devvp->v_vflag & VV_COPYONWRITE) == 0) 2483 return; 2484 for (;;) { 2485 VI_LOCK(devvp); 2486 sn = devvp->v_rdev->si_snapdata; 2487 if (sn == NULL) { 2488 VI_UNLOCK(devvp); 2489 return; 2490 } 2491 if (lockmgr(&sn->sn_lock, 2492 LK_INTERLOCK | LK_EXCLUSIVE | LK_SLEEPFAIL, 2493 VI_MTX(devvp)) == 0) 2494 break; 2495 } 2496 TAILQ_FOREACH(ip, &sn->sn_head, i_nextsnap) { 2497 vp = ITOV(ip); 2498 ffs_syncvnode(vp, waitfor, NO_INO_UPDT); 2499 } 2500 lockmgr(&sn->sn_lock, LK_RELEASE, NULL); 2501 } 2502 2503 /* 2504 * Read the specified block into the given buffer. 2505 * Much of this boiler-plate comes from bwrite(). 2506 */ 2507 static int 2508 readblock(vp, bp, lbn) 2509 struct vnode *vp; 2510 struct buf *bp; 2511 ufs2_daddr_t lbn; 2512 { 2513 struct inode *ip; 2514 struct bio *bip; 2515 struct fs *fs; 2516 2517 ip = VTOI(vp); 2518 fs = ITOFS(ip); 2519 2520 bip = g_alloc_bio(); 2521 bip->bio_cmd = BIO_READ; 2522 bip->bio_offset = dbtob(fsbtodb(fs, blkstofrags(fs, lbn))); 2523 bip->bio_data = bp->b_data; 2524 bip->bio_length = bp->b_bcount; 2525 bip->bio_done = NULL; 2526 2527 g_io_request(bip, ITODEVVP(ip)->v_bufobj.bo_private); 2528 bp->b_error = biowait(bip, "snaprdb"); 2529 g_destroy_bio(bip); 2530 return (bp->b_error); 2531 } 2532 2533 #endif 2534 2535 /* 2536 * Process file deletes that were deferred by ufs_inactive() due to 2537 * the file system being suspended. Transfer IN_LAZYACCESS into 2538 * IN_MODIFIED for vnodes that were accessed during suspension. 2539 */ 2540 void 2541 process_deferred_inactive(struct mount *mp) 2542 { 2543 struct vnode *vp, *mvp; 2544 struct inode *ip; 2545 struct thread *td; 2546 int error; 2547 2548 td = curthread; 2549 (void) vn_start_secondary_write(NULL, &mp, V_WAIT); 2550 loop: 2551 MNT_VNODE_FOREACH_ALL(vp, mp, mvp) { 2552 /* 2553 * IN_LAZYACCESS is checked here without holding any 2554 * vnode lock, but this flag is set only while holding 2555 * vnode interlock. 2556 */ 2557 if (vp->v_type == VNON || 2558 ((VTOI(vp)->i_flag & IN_LAZYACCESS) == 0 && 2559 ((vp->v_iflag & VI_OWEINACT) == 0 || vp->v_usecount > 0))) { 2560 VI_UNLOCK(vp); 2561 continue; 2562 } 2563 vholdl(vp); 2564 error = vn_lock(vp, LK_EXCLUSIVE | LK_INTERLOCK); 2565 if (error != 0) { 2566 vdrop(vp); 2567 if (error == ENOENT) 2568 continue; /* vnode recycled */ 2569 MNT_VNODE_FOREACH_ALL_ABORT(mp, mvp); 2570 goto loop; 2571 } 2572 ip = VTOI(vp); 2573 if ((ip->i_flag & IN_LAZYACCESS) != 0) { 2574 ip->i_flag &= ~IN_LAZYACCESS; 2575 ip->i_flag |= IN_MODIFIED; 2576 } 2577 VI_LOCK(vp); 2578 if ((vp->v_iflag & VI_OWEINACT) == 0 || vp->v_usecount > 0) { 2579 VI_UNLOCK(vp); 2580 VOP_UNLOCK(vp, 0); 2581 vdrop(vp); 2582 continue; 2583 } 2584 vinactive(vp, td); 2585 VNASSERT((vp->v_iflag & VI_OWEINACT) == 0, vp, 2586 ("process_deferred_inactive: got VI_OWEINACT")); 2587 VI_UNLOCK(vp); 2588 VOP_UNLOCK(vp, 0); 2589 vdrop(vp); 2590 } 2591 vn_finished_secondary_write(mp); 2592 } 2593 2594 #ifndef NO_FFS_SNAPSHOT 2595 2596 static struct snapdata * 2597 ffs_snapdata_alloc(void) 2598 { 2599 struct snapdata *sn; 2600 2601 /* 2602 * Fetch a snapdata from the free list if there is one available. 2603 */ 2604 mtx_lock(&snapfree_lock); 2605 sn = LIST_FIRST(&snapfree); 2606 if (sn != NULL) 2607 LIST_REMOVE(sn, sn_link); 2608 mtx_unlock(&snapfree_lock); 2609 if (sn != NULL) 2610 return (sn); 2611 /* 2612 * If there were no free snapdatas allocate one. 2613 */ 2614 sn = malloc(sizeof *sn, M_UFSMNT, M_WAITOK | M_ZERO); 2615 TAILQ_INIT(&sn->sn_head); 2616 lockinit(&sn->sn_lock, PVFS, "snaplk", VLKTIMEOUT, 2617 LK_CANRECURSE | LK_NOSHARE); 2618 return (sn); 2619 } 2620 2621 /* 2622 * The snapdata is never freed because we can not be certain that 2623 * there are no threads sleeping on the snap lock. Persisting 2624 * them permanently avoids costly synchronization in ffs_lock(). 2625 */ 2626 static void 2627 ffs_snapdata_free(struct snapdata *sn) 2628 { 2629 mtx_lock(&snapfree_lock); 2630 LIST_INSERT_HEAD(&snapfree, sn, sn_link); 2631 mtx_unlock(&snapfree_lock); 2632 } 2633 2634 /* Try to free snapdata associated with devvp */ 2635 static void 2636 try_free_snapdata(struct vnode *devvp) 2637 { 2638 struct snapdata *sn; 2639 ufs2_daddr_t *snapblklist; 2640 2641 ASSERT_VI_LOCKED(devvp, "try_free_snapdata"); 2642 sn = devvp->v_rdev->si_snapdata; 2643 2644 if (sn == NULL || TAILQ_FIRST(&sn->sn_head) != NULL || 2645 (devvp->v_vflag & VV_COPYONWRITE) == 0) { 2646 VI_UNLOCK(devvp); 2647 return; 2648 } 2649 2650 devvp->v_rdev->si_snapdata = NULL; 2651 devvp->v_vflag &= ~VV_COPYONWRITE; 2652 lockmgr(&sn->sn_lock, LK_DRAIN|LK_INTERLOCK, VI_MTX(devvp)); 2653 snapblklist = sn->sn_blklist; 2654 sn->sn_blklist = NULL; 2655 sn->sn_listsize = 0; 2656 lockmgr(&sn->sn_lock, LK_RELEASE, NULL); 2657 if (snapblklist != NULL) 2658 free(snapblklist, M_UFSMNT); 2659 ffs_snapdata_free(sn); 2660 } 2661 2662 static struct snapdata * 2663 ffs_snapdata_acquire(struct vnode *devvp) 2664 { 2665 struct snapdata *nsn, *sn; 2666 int error; 2667 2668 /* 2669 * Allocate a free snapdata. This is done before acquiring the 2670 * devvp lock to avoid allocation while the devvp interlock is 2671 * held. 2672 */ 2673 nsn = ffs_snapdata_alloc(); 2674 2675 for (;;) { 2676 VI_LOCK(devvp); 2677 sn = devvp->v_rdev->si_snapdata; 2678 if (sn == NULL) { 2679 /* 2680 * This is the first snapshot on this 2681 * filesystem and we use our pre-allocated 2682 * snapdata. Publish sn with the sn_lock 2683 * owned by us, to avoid the race. 2684 */ 2685 error = lockmgr(&nsn->sn_lock, LK_EXCLUSIVE | 2686 LK_NOWAIT, NULL); 2687 if (error != 0) 2688 panic("leaked sn, lockmgr error %d", error); 2689 sn = devvp->v_rdev->si_snapdata = nsn; 2690 VI_UNLOCK(devvp); 2691 nsn = NULL; 2692 break; 2693 } 2694 2695 /* 2696 * There is a snapshots which already exists on this 2697 * filesystem, grab a reference to the common lock. 2698 */ 2699 error = lockmgr(&sn->sn_lock, LK_INTERLOCK | 2700 LK_EXCLUSIVE | LK_SLEEPFAIL, VI_MTX(devvp)); 2701 if (error == 0) 2702 break; 2703 } 2704 2705 /* 2706 * Free any unused snapdata. 2707 */ 2708 if (nsn != NULL) 2709 ffs_snapdata_free(nsn); 2710 2711 return (sn); 2712 } 2713 2714 #endif 2715