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