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sys/ufs/ffs/ffs_snapshot.c
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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: releng/10.1/sys/ufs/ffs/ffs_snapshot.c 262779 2014-03-05 04:23:19Z pfg $"); 38 39 #include "opt_quota.h" 40 41 #include <sys/param.h> 42 #include <sys/kernel.h> 43 #include <sys/systm.h> 44 #include <sys/conf.h> 45 #include <sys/bio.h> 46 #include <sys/buf.h> 47 #include <sys/fcntl.h> 48 #include <sys/proc.h> 49 #include <sys/namei.h> 50 #include <sys/sched.h> 51 #include <sys/stat.h> 52 #include <sys/malloc.h> 53 #include <sys/mount.h> 54 #include <sys/resource.h> 55 #include <sys/resourcevar.h> 56 #include <sys/rwlock.h> 57 #include <sys/vnode.h> 58 59 #include <geom/geom.h> 60 61 #include <ufs/ufs/extattr.h> 62 #include <ufs/ufs/quota.h> 63 #include <ufs/ufs/ufsmount.h> 64 #include <ufs/ufs/inode.h> 65 #include <ufs/ufs/ufs_extern.h> 66 67 #include <ufs/ffs/fs.h> 68 #include <ufs/ffs/ffs_extern.h> 69 70 #define KERNCRED thread0.td_ucred 71 #define DEBUG 1 72 73 #include "opt_ffs.h" 74 75 #ifdef NO_FFS_SNAPSHOT 76 int 77 ffs_snapshot(mp, snapfile) 78 struct mount *mp; 79 char *snapfile; 80 { 81 return (EINVAL); 82 } 83 84 int 85 ffs_snapblkfree(fs, devvp, bno, size, inum, vtype, wkhd) 86 struct fs *fs; 87 struct vnode *devvp; 88 ufs2_daddr_t bno; 89 long size; 90 ino_t inum; 91 enum vtype vtype; 92 struct workhead *wkhd; 93 { 94 return (EINVAL); 95 } 96 97 void 98 ffs_snapremove(vp) 99 struct vnode *vp; 100 { 101 } 102 103 void 104 ffs_snapshot_mount(mp) 105 struct mount *mp; 106 { 107 } 108 109 void 110 ffs_snapshot_unmount(mp) 111 struct mount *mp; 112 { 113 } 114 115 void 116 ffs_snapgone(ip) 117 struct inode *ip; 118 { 119 } 120 121 int 122 ffs_copyonwrite(devvp, bp) 123 struct vnode *devvp; 124 struct buf *bp; 125 { 126 return (EINVAL); 127 } 128 129 void 130 ffs_sync_snap(mp, waitfor) 131 struct mount *mp; 132 int waitfor; 133 { 134 } 135 136 #else 137 FEATURE(ffs_snapshot, "FFS snapshot support"); 138 139 LIST_HEAD(, snapdata) snapfree; 140 static struct mtx snapfree_lock; 141 MTX_SYSINIT(ffs_snapfree, &snapfree_lock, "snapdata free list", MTX_DEF); 142 143 static int cgaccount(int, struct vnode *, struct buf *, int); 144 static int expunge_ufs1(struct vnode *, struct inode *, struct fs *, 145 int (*)(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *, struct fs *, 146 ufs_lbn_t, int), int, int); 147 static int indiracct_ufs1(struct vnode *, struct vnode *, int, 148 ufs1_daddr_t, ufs_lbn_t, ufs_lbn_t, ufs_lbn_t, ufs_lbn_t, struct fs *, 149 int (*)(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *, struct fs *, 150 ufs_lbn_t, int), int); 151 static int fullacct_ufs1(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *, 152 struct fs *, ufs_lbn_t, int); 153 static int snapacct_ufs1(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *, 154 struct fs *, ufs_lbn_t, int); 155 static int mapacct_ufs1(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *, 156 struct fs *, ufs_lbn_t, int); 157 static int expunge_ufs2(struct vnode *, struct inode *, struct fs *, 158 int (*)(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *, struct fs *, 159 ufs_lbn_t, int), int, int); 160 static int indiracct_ufs2(struct vnode *, struct vnode *, int, 161 ufs2_daddr_t, ufs_lbn_t, ufs_lbn_t, ufs_lbn_t, ufs_lbn_t, struct fs *, 162 int (*)(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *, struct fs *, 163 ufs_lbn_t, int), int); 164 static int fullacct_ufs2(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *, 165 struct fs *, ufs_lbn_t, int); 166 static int snapacct_ufs2(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *, 167 struct fs *, ufs_lbn_t, int); 168 static int mapacct_ufs2(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *, 169 struct fs *, ufs_lbn_t, int); 170 static int readblock(struct vnode *vp, struct buf *, ufs2_daddr_t); 171 static void try_free_snapdata(struct vnode *devvp); 172 static struct snapdata *ffs_snapdata_acquire(struct vnode *devvp); 173 static int ffs_bp_snapblk(struct vnode *, struct buf *); 174 175 /* 176 * To ensure the consistency of snapshots across crashes, we must 177 * synchronously write out copied blocks before allowing the 178 * originals to be modified. Because of the rather severe speed 179 * penalty that this imposes, the code normally only ensures 180 * persistence for the filesystem metadata contained within a 181 * snapshot. Setting the following flag allows this crash 182 * persistence to be enabled for file contents. 183 */ 184 int dopersistence = 0; 185 186 #ifdef DEBUG 187 #include <sys/sysctl.h> 188 SYSCTL_INT(_debug, OID_AUTO, dopersistence, CTLFLAG_RW, &dopersistence, 0, ""); 189 static int snapdebug = 0; 190 SYSCTL_INT(_debug, OID_AUTO, snapdebug, CTLFLAG_RW, &snapdebug, 0, ""); 191 int collectsnapstats = 0; 192 SYSCTL_INT(_debug, OID_AUTO, collectsnapstats, CTLFLAG_RW, &collectsnapstats, 193 0, ""); 194 #endif /* DEBUG */ 195 196 /* 197 * Create a snapshot file and initialize it for the filesystem. 198 */ 199 int 200 ffs_snapshot(mp, snapfile) 201 struct mount *mp; 202 char *snapfile; 203 { 204 ufs2_daddr_t numblks, blkno, *blkp, *snapblklist; 205 int error, cg, snaploc; 206 int i, size, len, loc; 207 ufs2_daddr_t blockno; 208 uint64_t flag; 209 struct timespec starttime = {0, 0}, endtime; 210 char saved_nice = 0; 211 long redo = 0, snaplistsize = 0; 212 int32_t *lp; 213 void *space; 214 struct fs *copy_fs = NULL, *fs; 215 struct thread *td = curthread; 216 struct inode *ip, *xp; 217 struct buf *bp, *nbp, *ibp; 218 struct nameidata nd; 219 struct mount *wrtmp; 220 struct vattr vat; 221 struct vnode *vp, *xvp, *mvp, *devvp; 222 struct uio auio; 223 struct iovec aiov; 224 struct snapdata *sn; 225 struct ufsmount *ump; 226 227 ump = VFSTOUFS(mp); 228 fs = ump->um_fs; 229 sn = NULL; 230 /* 231 * At the moment, journaled soft updates cannot support 232 * taking snapshots. 233 */ 234 if (MOUNTEDSUJ(mp)) { 235 vfs_mount_error(mp, "%s: Snapshots are not yet supported when " 236 "running with journaled soft updates", fs->fs_fsmnt); 237 return (EOPNOTSUPP); 238 } 239 MNT_ILOCK(mp); 240 flag = mp->mnt_flag; 241 MNT_IUNLOCK(mp); 242 /* 243 * Need to serialize access to snapshot code per filesystem. 244 */ 245 /* 246 * Assign a snapshot slot in the superblock. 247 */ 248 UFS_LOCK(ump); 249 for (snaploc = 0; snaploc < FSMAXSNAP; snaploc++) 250 if (fs->fs_snapinum[snaploc] == 0) 251 break; 252 UFS_UNLOCK(ump); 253 if (snaploc == FSMAXSNAP) 254 return (ENOSPC); 255 /* 256 * Create the snapshot file. 257 */ 258 restart: 259 NDINIT(&nd, CREATE, LOCKPARENT | LOCKLEAF, UIO_SYSSPACE, snapfile, td); 260 if ((error = namei(&nd)) != 0) 261 return (error); 262 if (nd.ni_vp != NULL) { 263 vput(nd.ni_vp); 264 error = EEXIST; 265 } 266 if (nd.ni_dvp->v_mount != mp) 267 error = EXDEV; 268 if (error) { 269 NDFREE(&nd, NDF_ONLY_PNBUF); 270 if (nd.ni_dvp == nd.ni_vp) 271 vrele(nd.ni_dvp); 272 else 273 vput(nd.ni_dvp); 274 return (error); 275 } 276 VATTR_NULL(&vat); 277 vat.va_type = VREG; 278 vat.va_mode = S_IRUSR; 279 vat.va_vaflags |= VA_EXCLUSIVE; 280 if (VOP_GETWRITEMOUNT(nd.ni_dvp, &wrtmp)) 281 wrtmp = NULL; 282 if (wrtmp != mp) 283 panic("ffs_snapshot: mount mismatch"); 284 vfs_rel(wrtmp); 285 if (vn_start_write(NULL, &wrtmp, V_NOWAIT) != 0) { 286 NDFREE(&nd, NDF_ONLY_PNBUF); 287 vput(nd.ni_dvp); 288 if ((error = vn_start_write(NULL, &wrtmp, 289 V_XSLEEP | PCATCH)) != 0) 290 return (error); 291 goto restart; 292 } 293 error = VOP_CREATE(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vat); 294 VOP_UNLOCK(nd.ni_dvp, 0); 295 if (error) { 296 NDFREE(&nd, NDF_ONLY_PNBUF); 297 vn_finished_write(wrtmp); 298 vrele(nd.ni_dvp); 299 return (error); 300 } 301 vp = nd.ni_vp; 302 vp->v_vflag |= VV_SYSTEM; 303 ip = VTOI(vp); 304 devvp = ip->i_devvp; 305 /* 306 * Allocate and copy the last block contents so as to be able 307 * to set size to that of the filesystem. 308 */ 309 numblks = howmany(fs->fs_size, fs->fs_frag); 310 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)(numblks - 1)), 311 fs->fs_bsize, KERNCRED, BA_CLRBUF, &bp); 312 if (error) 313 goto out; 314 ip->i_size = lblktosize(fs, (off_t)numblks); 315 DIP_SET(ip, i_size, ip->i_size); 316 ip->i_flag |= IN_CHANGE | IN_UPDATE; 317 error = readblock(vp, bp, numblks - 1); 318 bawrite(bp); 319 if (error != 0) 320 goto out; 321 /* 322 * Preallocate critical data structures so that we can copy 323 * them in without further allocation after we suspend all 324 * operations on the filesystem. We would like to just release 325 * the allocated buffers without writing them since they will 326 * be filled in below once we are ready to go, but this upsets 327 * the soft update code, so we go ahead and write the new buffers. 328 * 329 * Allocate all indirect blocks and mark all of them as not 330 * needing to be copied. 331 */ 332 for (blkno = NDADDR; blkno < numblks; blkno += NINDIR(fs)) { 333 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)blkno), 334 fs->fs_bsize, td->td_ucred, BA_METAONLY, &ibp); 335 if (error) 336 goto out; 337 bawrite(ibp); 338 } 339 /* 340 * Allocate copies for the superblock and its summary information. 341 */ 342 error = UFS_BALLOC(vp, fs->fs_sblockloc, fs->fs_sbsize, KERNCRED, 343 0, &nbp); 344 if (error) 345 goto out; 346 bawrite(nbp); 347 blkno = fragstoblks(fs, fs->fs_csaddr); 348 len = howmany(fs->fs_cssize, fs->fs_bsize); 349 for (loc = 0; loc < len; loc++) { 350 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)(blkno + loc)), 351 fs->fs_bsize, KERNCRED, 0, &nbp); 352 if (error) 353 goto out; 354 bawrite(nbp); 355 } 356 /* 357 * Allocate all cylinder group blocks. 358 */ 359 for (cg = 0; cg < fs->fs_ncg; cg++) { 360 error = UFS_BALLOC(vp, lfragtosize(fs, cgtod(fs, cg)), 361 fs->fs_bsize, KERNCRED, 0, &nbp); 362 if (error) 363 goto out; 364 bawrite(nbp); 365 if (cg % 10 == 0) 366 ffs_syncvnode(vp, MNT_WAIT, 0); 367 } 368 /* 369 * Copy all the cylinder group maps. Although the 370 * filesystem is still active, we hope that only a few 371 * cylinder groups will change between now and when we 372 * suspend operations. Thus, we will be able to quickly 373 * touch up the few cylinder groups that changed during 374 * the suspension period. 375 */ 376 len = howmany(fs->fs_ncg, NBBY); 377 space = malloc(len, M_DEVBUF, M_WAITOK|M_ZERO); 378 UFS_LOCK(ump); 379 fs->fs_active = space; 380 UFS_UNLOCK(ump); 381 for (cg = 0; cg < fs->fs_ncg; cg++) { 382 error = UFS_BALLOC(vp, lfragtosize(fs, cgtod(fs, cg)), 383 fs->fs_bsize, KERNCRED, 0, &nbp); 384 if (error) 385 goto out; 386 error = cgaccount(cg, vp, nbp, 1); 387 bawrite(nbp); 388 if (cg % 10 == 0) 389 ffs_syncvnode(vp, MNT_WAIT, 0); 390 if (error) 391 goto out; 392 } 393 /* 394 * Change inode to snapshot type file. 395 */ 396 ip->i_flags |= SF_SNAPSHOT; 397 DIP_SET(ip, i_flags, ip->i_flags); 398 ip->i_flag |= IN_CHANGE | IN_UPDATE; 399 /* 400 * Ensure that the snapshot is completely on disk. 401 * Since we have marked it as a snapshot it is safe to 402 * unlock it as no process will be allowed to write to it. 403 */ 404 if ((error = ffs_syncvnode(vp, MNT_WAIT, 0)) != 0) 405 goto out; 406 VOP_UNLOCK(vp, 0); 407 /* 408 * All allocations are done, so we can now snapshot the system. 409 * 410 * Recind nice scheduling while running with the filesystem suspended. 411 */ 412 if (td->td_proc->p_nice > 0) { 413 struct proc *p; 414 415 p = td->td_proc; 416 PROC_LOCK(p); 417 saved_nice = p->p_nice; 418 sched_nice(p, 0); 419 PROC_UNLOCK(p); 420 } 421 /* 422 * Suspend operation on filesystem. 423 */ 424 for (;;) { 425 vn_finished_write(wrtmp); 426 if ((error = vfs_write_suspend(vp->v_mount, 0)) != 0) { 427 vn_start_write(NULL, &wrtmp, V_WAIT); 428 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 429 goto out; 430 } 431 if (mp->mnt_kern_flag & MNTK_SUSPENDED) 432 break; 433 vn_start_write(NULL, &wrtmp, V_WAIT); 434 } 435 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 436 if (ip->i_effnlink == 0) { 437 error = ENOENT; /* Snapshot file unlinked */ 438 goto out1; 439 } 440 if (collectsnapstats) 441 nanotime(&starttime); 442 443 /* The last block might have changed. Copy it again to be sure. */ 444 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)(numblks - 1)), 445 fs->fs_bsize, KERNCRED, BA_CLRBUF, &bp); 446 if (error != 0) 447 goto out1; 448 error = readblock(vp, bp, numblks - 1); 449 bp->b_flags |= B_VALIDSUSPWRT; 450 bawrite(bp); 451 if (error != 0) 452 goto out1; 453 /* 454 * First, copy all the cylinder group maps that have changed. 455 */ 456 for (cg = 0; cg < fs->fs_ncg; cg++) { 457 if ((ACTIVECGNUM(fs, cg) & ACTIVECGOFF(cg)) != 0) 458 continue; 459 redo++; 460 error = UFS_BALLOC(vp, lfragtosize(fs, cgtod(fs, cg)), 461 fs->fs_bsize, KERNCRED, 0, &nbp); 462 if (error) 463 goto out1; 464 error = cgaccount(cg, vp, nbp, 2); 465 bawrite(nbp); 466 if (error) 467 goto out1; 468 } 469 /* 470 * Grab a copy of the superblock and its summary information. 471 * We delay writing it until the suspension is released below. 472 */ 473 copy_fs = malloc((u_long)fs->fs_bsize, M_UFSMNT, M_WAITOK); 474 bcopy(fs, copy_fs, fs->fs_sbsize); 475 if ((fs->fs_flags & (FS_UNCLEAN | FS_NEEDSFSCK)) == 0) 476 copy_fs->fs_clean = 1; 477 size = fs->fs_bsize < SBLOCKSIZE ? fs->fs_bsize : SBLOCKSIZE; 478 if (fs->fs_sbsize < size) 479 bzero(&((char *)copy_fs)[fs->fs_sbsize], 480 size - fs->fs_sbsize); 481 size = blkroundup(fs, fs->fs_cssize); 482 if (fs->fs_contigsumsize > 0) 483 size += fs->fs_ncg * sizeof(int32_t); 484 space = malloc((u_long)size, M_UFSMNT, M_WAITOK); 485 copy_fs->fs_csp = space; 486 bcopy(fs->fs_csp, copy_fs->fs_csp, fs->fs_cssize); 487 space = (char *)space + fs->fs_cssize; 488 loc = howmany(fs->fs_cssize, fs->fs_fsize); 489 i = fs->fs_frag - loc % fs->fs_frag; 490 len = (i == fs->fs_frag) ? 0 : i * fs->fs_fsize; 491 if (len > 0) { 492 if ((error = bread(devvp, fsbtodb(fs, fs->fs_csaddr + loc), 493 len, KERNCRED, &bp)) != 0) { 494 brelse(bp); 495 free(copy_fs->fs_csp, M_UFSMNT); 496 free(copy_fs, M_UFSMNT); 497 copy_fs = NULL; 498 goto out1; 499 } 500 bcopy(bp->b_data, space, (u_int)len); 501 space = (char *)space + len; 502 bp->b_flags |= B_INVAL | B_NOCACHE; 503 brelse(bp); 504 } 505 if (fs->fs_contigsumsize > 0) { 506 copy_fs->fs_maxcluster = lp = space; 507 for (i = 0; i < fs->fs_ncg; i++) 508 *lp++ = fs->fs_contigsumsize; 509 } 510 /* 511 * We must check for active files that have been unlinked 512 * (e.g., with a zero link count). We have to expunge all 513 * trace of these files from the snapshot so that they are 514 * not reclaimed prematurely by fsck or unnecessarily dumped. 515 * We turn off the MNTK_SUSPENDED flag to avoid a panic from 516 * spec_strategy about writing on a suspended filesystem. 517 * Note that we skip unlinked snapshot files as they will 518 * be handled separately below. 519 * 520 * We also calculate the needed size for the snapshot list. 521 */ 522 snaplistsize = fs->fs_ncg + howmany(fs->fs_cssize, fs->fs_bsize) + 523 FSMAXSNAP + 1 /* superblock */ + 1 /* last block */ + 1 /* size */; 524 MNT_ILOCK(mp); 525 mp->mnt_kern_flag &= ~MNTK_SUSPENDED; 526 MNT_IUNLOCK(mp); 527 loop: 528 MNT_VNODE_FOREACH_ALL(xvp, mp, mvp) { 529 if ((xvp->v_usecount == 0 && 530 (xvp->v_iflag & (VI_OWEINACT | VI_DOINGINACT)) == 0) || 531 xvp->v_type == VNON || 532 IS_SNAPSHOT(VTOI(xvp))) { 533 VI_UNLOCK(xvp); 534 continue; 535 } 536 /* 537 * We can skip parent directory vnode because it must have 538 * this snapshot file in it. 539 */ 540 if (xvp == nd.ni_dvp) { 541 VI_UNLOCK(xvp); 542 continue; 543 } 544 vholdl(xvp); 545 if (vn_lock(xvp, LK_EXCLUSIVE | LK_INTERLOCK) != 0) { 546 MNT_VNODE_FOREACH_ALL_ABORT(mp, mvp); 547 vdrop(xvp); 548 goto loop; 549 } 550 VI_LOCK(xvp); 551 if (xvp->v_usecount == 0 && 552 (xvp->v_iflag & (VI_OWEINACT | VI_DOINGINACT)) == 0) { 553 VI_UNLOCK(xvp); 554 VOP_UNLOCK(xvp, 0); 555 vdrop(xvp); 556 continue; 557 } 558 VI_UNLOCK(xvp); 559 if (snapdebug) 560 vprint("ffs_snapshot: busy vnode", xvp); 561 if (VOP_GETATTR(xvp, &vat, td->td_ucred) == 0 && 562 vat.va_nlink > 0) { 563 VOP_UNLOCK(xvp, 0); 564 vdrop(xvp); 565 continue; 566 } 567 xp = VTOI(xvp); 568 if (ffs_checkfreefile(copy_fs, vp, xp->i_number)) { 569 VOP_UNLOCK(xvp, 0); 570 vdrop(xvp); 571 continue; 572 } 573 /* 574 * If there is a fragment, clear it here. 575 */ 576 blkno = 0; 577 loc = howmany(xp->i_size, fs->fs_bsize) - 1; 578 if (loc < NDADDR) { 579 len = fragroundup(fs, blkoff(fs, xp->i_size)); 580 if (len != 0 && len < fs->fs_bsize) { 581 ffs_blkfree(ump, copy_fs, vp, 582 DIP(xp, i_db[loc]), len, xp->i_number, 583 xvp->v_type, NULL); 584 blkno = DIP(xp, i_db[loc]); 585 DIP_SET(xp, i_db[loc], 0); 586 } 587 } 588 snaplistsize += 1; 589 if (xp->i_ump->um_fstype == UFS1) 590 error = expunge_ufs1(vp, xp, copy_fs, fullacct_ufs1, 591 BLK_NOCOPY, 1); 592 else 593 error = expunge_ufs2(vp, xp, copy_fs, fullacct_ufs2, 594 BLK_NOCOPY, 1); 595 if (blkno) 596 DIP_SET(xp, i_db[loc], blkno); 597 if (!error) 598 error = ffs_freefile(ump, copy_fs, vp, xp->i_number, 599 xp->i_mode, NULL); 600 VOP_UNLOCK(xvp, 0); 601 vdrop(xvp); 602 if (error) { 603 free(copy_fs->fs_csp, M_UFSMNT); 604 free(copy_fs, M_UFSMNT); 605 copy_fs = NULL; 606 MNT_VNODE_FOREACH_ALL_ABORT(mp, mvp); 607 goto out1; 608 } 609 } 610 /* 611 * Erase the journal file from the snapshot. 612 */ 613 if (fs->fs_flags & FS_SUJ) { 614 error = softdep_journal_lookup(mp, &xvp); 615 if (error) { 616 free(copy_fs->fs_csp, M_UFSMNT); 617 free(copy_fs, M_UFSMNT); 618 copy_fs = NULL; 619 goto out1; 620 } 621 xp = VTOI(xvp); 622 if (xp->i_ump->um_fstype == UFS1) 623 error = expunge_ufs1(vp, xp, copy_fs, fullacct_ufs1, 624 BLK_NOCOPY, 0); 625 else 626 error = expunge_ufs2(vp, xp, copy_fs, fullacct_ufs2, 627 BLK_NOCOPY, 0); 628 vput(xvp); 629 } 630 /* 631 * Acquire a lock on the snapdata structure, creating it if necessary. 632 */ 633 sn = ffs_snapdata_acquire(devvp); 634 /* 635 * Change vnode to use shared snapshot lock instead of the original 636 * private lock. 637 */ 638 vp->v_vnlock = &sn->sn_lock; 639 lockmgr(&vp->v_lock, LK_RELEASE, NULL); 640 xp = TAILQ_FIRST(&sn->sn_head); 641 /* 642 * If this is the first snapshot on this filesystem, then we need 643 * to allocate the space for the list of preallocated snapshot blocks. 644 * This list will be refined below, but this preliminary one will 645 * keep us out of deadlock until the full one is ready. 646 */ 647 if (xp == NULL) { 648 snapblklist = malloc(snaplistsize * sizeof(daddr_t), 649 M_UFSMNT, M_WAITOK); 650 blkp = &snapblklist[1]; 651 *blkp++ = lblkno(fs, fs->fs_sblockloc); 652 blkno = fragstoblks(fs, fs->fs_csaddr); 653 for (cg = 0; cg < fs->fs_ncg; cg++) { 654 if (fragstoblks(fs, cgtod(fs, cg) > blkno)) 655 break; 656 *blkp++ = fragstoblks(fs, cgtod(fs, cg)); 657 } 658 len = howmany(fs->fs_cssize, fs->fs_bsize); 659 for (loc = 0; loc < len; loc++) 660 *blkp++ = blkno + loc; 661 for (; cg < fs->fs_ncg; cg++) 662 *blkp++ = fragstoblks(fs, cgtod(fs, cg)); 663 snapblklist[0] = blkp - snapblklist; 664 VI_LOCK(devvp); 665 if (sn->sn_blklist != NULL) 666 panic("ffs_snapshot: non-empty list"); 667 sn->sn_blklist = snapblklist; 668 sn->sn_listsize = blkp - snapblklist; 669 VI_UNLOCK(devvp); 670 } 671 /* 672 * Record snapshot inode. Since this is the newest snapshot, 673 * it must be placed at the end of the list. 674 */ 675 VI_LOCK(devvp); 676 fs->fs_snapinum[snaploc] = ip->i_number; 677 if (ip->i_nextsnap.tqe_prev != 0) 678 panic("ffs_snapshot: %ju already on list", 679 (uintmax_t)ip->i_number); 680 TAILQ_INSERT_TAIL(&sn->sn_head, ip, i_nextsnap); 681 devvp->v_vflag |= VV_COPYONWRITE; 682 VI_UNLOCK(devvp); 683 ASSERT_VOP_LOCKED(vp, "ffs_snapshot vp"); 684 out1: 685 KASSERT((sn != NULL && copy_fs != NULL && error == 0) || 686 (sn == NULL && copy_fs == NULL && error != 0), 687 ("email phk@ and mckusick@")); 688 /* 689 * Resume operation on filesystem. 690 */ 691 vfs_write_resume(vp->v_mount, VR_START_WRITE | VR_NO_SUSPCLR); 692 if (collectsnapstats && starttime.tv_sec > 0) { 693 nanotime(&endtime); 694 timespecsub(&endtime, &starttime); 695 printf("%s: suspended %ld.%03ld sec, redo %ld of %d\n", 696 vp->v_mount->mnt_stat.f_mntonname, (long)endtime.tv_sec, 697 endtime.tv_nsec / 1000000, redo, fs->fs_ncg); 698 } 699 if (copy_fs == NULL) 700 goto out; 701 /* 702 * Copy allocation information from all the snapshots in 703 * this snapshot and then expunge them from its view. 704 */ 705 TAILQ_FOREACH(xp, &sn->sn_head, i_nextsnap) { 706 if (xp == ip) 707 break; 708 if (xp->i_ump->um_fstype == UFS1) 709 error = expunge_ufs1(vp, xp, fs, snapacct_ufs1, 710 BLK_SNAP, 0); 711 else 712 error = expunge_ufs2(vp, xp, fs, snapacct_ufs2, 713 BLK_SNAP, 0); 714 if (error == 0 && xp->i_effnlink == 0) { 715 error = ffs_freefile(ump, 716 copy_fs, 717 vp, 718 xp->i_number, 719 xp->i_mode, NULL); 720 } 721 if (error) { 722 fs->fs_snapinum[snaploc] = 0; 723 goto done; 724 } 725 } 726 /* 727 * Allocate space for the full list of preallocated snapshot blocks. 728 */ 729 snapblklist = malloc(snaplistsize * sizeof(daddr_t), 730 M_UFSMNT, M_WAITOK); 731 ip->i_snapblklist = &snapblklist[1]; 732 /* 733 * Expunge the blocks used by the snapshots from the set of 734 * blocks marked as used in the snapshot bitmaps. Also, collect 735 * the list of allocated blocks in i_snapblklist. 736 */ 737 if (ip->i_ump->um_fstype == UFS1) 738 error = expunge_ufs1(vp, ip, copy_fs, mapacct_ufs1, 739 BLK_SNAP, 0); 740 else 741 error = expunge_ufs2(vp, ip, copy_fs, mapacct_ufs2, 742 BLK_SNAP, 0); 743 if (error) { 744 fs->fs_snapinum[snaploc] = 0; 745 free(snapblklist, M_UFSMNT); 746 goto done; 747 } 748 if (snaplistsize < ip->i_snapblklist - snapblklist) 749 panic("ffs_snapshot: list too small"); 750 snaplistsize = ip->i_snapblklist - snapblklist; 751 snapblklist[0] = snaplistsize; 752 ip->i_snapblklist = 0; 753 /* 754 * Write out the list of allocated blocks to the end of the snapshot. 755 */ 756 auio.uio_iov = &aiov; 757 auio.uio_iovcnt = 1; 758 aiov.iov_base = (void *)snapblklist; 759 aiov.iov_len = snaplistsize * sizeof(daddr_t); 760 auio.uio_resid = aiov.iov_len; 761 auio.uio_offset = ip->i_size; 762 auio.uio_segflg = UIO_SYSSPACE; 763 auio.uio_rw = UIO_WRITE; 764 auio.uio_td = td; 765 if ((error = VOP_WRITE(vp, &auio, IO_UNIT, td->td_ucred)) != 0) { 766 fs->fs_snapinum[snaploc] = 0; 767 free(snapblklist, M_UFSMNT); 768 goto done; 769 } 770 /* 771 * Write the superblock and its summary information 772 * to the snapshot. 773 */ 774 blkno = fragstoblks(fs, fs->fs_csaddr); 775 len = howmany(fs->fs_cssize, fs->fs_bsize); 776 space = copy_fs->fs_csp; 777 for (loc = 0; loc < len; loc++) { 778 error = bread(vp, blkno + loc, fs->fs_bsize, KERNCRED, &nbp); 779 if (error) { 780 brelse(nbp); 781 fs->fs_snapinum[snaploc] = 0; 782 free(snapblklist, M_UFSMNT); 783 goto done; 784 } 785 bcopy(space, nbp->b_data, fs->fs_bsize); 786 space = (char *)space + fs->fs_bsize; 787 bawrite(nbp); 788 } 789 error = bread(vp, lblkno(fs, fs->fs_sblockloc), fs->fs_bsize, 790 KERNCRED, &nbp); 791 if (error) { 792 brelse(nbp); 793 } else { 794 loc = blkoff(fs, fs->fs_sblockloc); 795 bcopy((char *)copy_fs, &nbp->b_data[loc], (u_int)fs->fs_sbsize); 796 bawrite(nbp); 797 } 798 /* 799 * As this is the newest list, it is the most inclusive, so 800 * should replace the previous list. 801 */ 802 VI_LOCK(devvp); 803 space = sn->sn_blklist; 804 sn->sn_blklist = snapblklist; 805 sn->sn_listsize = snaplistsize; 806 VI_UNLOCK(devvp); 807 if (space != NULL) 808 free(space, M_UFSMNT); 809 /* 810 * Preallocate all the direct blocks in the snapshot inode so 811 * that we never have to write the inode itself to commit an 812 * update to the contents of the snapshot. Note that once 813 * created, the size of the snapshot will never change, so 814 * there will never be a need to write the inode except to 815 * update the non-integrity-critical time fields and 816 * allocated-block count. 817 */ 818 for (blockno = 0; blockno < NDADDR; blockno++) { 819 if (DIP(ip, i_db[blockno]) != 0) 820 continue; 821 error = UFS_BALLOC(vp, lblktosize(fs, blockno), 822 fs->fs_bsize, KERNCRED, BA_CLRBUF, &bp); 823 if (error) 824 break; 825 error = readblock(vp, bp, blockno); 826 bawrite(bp); 827 if (error != 0) 828 break; 829 } 830 done: 831 free(copy_fs->fs_csp, M_UFSMNT); 832 free(copy_fs, M_UFSMNT); 833 copy_fs = NULL; 834 out: 835 NDFREE(&nd, NDF_ONLY_PNBUF); 836 if (saved_nice > 0) { 837 struct proc *p; 838 839 p = td->td_proc; 840 PROC_LOCK(p); 841 sched_nice(td->td_proc, saved_nice); 842 PROC_UNLOCK(td->td_proc); 843 } 844 UFS_LOCK(ump); 845 if (fs->fs_active != 0) { 846 free(fs->fs_active, M_DEVBUF); 847 fs->fs_active = 0; 848 } 849 UFS_UNLOCK(ump); 850 MNT_ILOCK(mp); 851 mp->mnt_flag = (mp->mnt_flag & MNT_QUOTA) | (flag & ~MNT_QUOTA); 852 MNT_IUNLOCK(mp); 853 if (error) 854 (void) ffs_truncate(vp, (off_t)0, 0, NOCRED); 855 (void) ffs_syncvnode(vp, MNT_WAIT, 0); 856 if (error) 857 vput(vp); 858 else 859 VOP_UNLOCK(vp, 0); 860 vrele(nd.ni_dvp); 861 vn_finished_write(wrtmp); 862 process_deferred_inactive(mp); 863 return (error); 864 } 865 866 /* 867 * Copy a cylinder group map. All the unallocated blocks are marked 868 * BLK_NOCOPY so that the snapshot knows that it need not copy them 869 * if they are later written. If passno is one, then this is a first 870 * pass, so only setting needs to be done. If passno is 2, then this 871 * is a revision to a previous pass which must be undone as the 872 * replacement pass is done. 873 */ 874 static int 875 cgaccount(cg, vp, nbp, passno) 876 int cg; 877 struct vnode *vp; 878 struct buf *nbp; 879 int passno; 880 { 881 struct buf *bp, *ibp; 882 struct inode *ip; 883 struct cg *cgp; 884 struct fs *fs; 885 ufs2_daddr_t base, numblks; 886 int error, len, loc, indiroff; 887 888 ip = VTOI(vp); 889 fs = ip->i_fs; 890 error = bread(ip->i_devvp, fsbtodb(fs, cgtod(fs, cg)), 891 (int)fs->fs_cgsize, KERNCRED, &bp); 892 if (error) { 893 brelse(bp); 894 return (error); 895 } 896 cgp = (struct cg *)bp->b_data; 897 if (!cg_chkmagic(cgp)) { 898 brelse(bp); 899 return (EIO); 900 } 901 UFS_LOCK(ip->i_ump); 902 ACTIVESET(fs, cg); 903 /* 904 * Recomputation of summary information might not have been performed 905 * at mount time. Sync up summary information for current cylinder 906 * group while data is in memory to ensure that result of background 907 * fsck is slightly more consistent. 908 */ 909 fs->fs_cs(fs, cg) = cgp->cg_cs; 910 UFS_UNLOCK(ip->i_ump); 911 bcopy(bp->b_data, nbp->b_data, fs->fs_cgsize); 912 if (fs->fs_cgsize < fs->fs_bsize) 913 bzero(&nbp->b_data[fs->fs_cgsize], 914 fs->fs_bsize - fs->fs_cgsize); 915 cgp = (struct cg *)nbp->b_data; 916 bqrelse(bp); 917 if (passno == 2) 918 nbp->b_flags |= B_VALIDSUSPWRT; 919 numblks = howmany(fs->fs_size, fs->fs_frag); 920 len = howmany(fs->fs_fpg, fs->fs_frag); 921 base = cgbase(fs, cg) / fs->fs_frag; 922 if (base + len >= numblks) 923 len = numblks - base - 1; 924 loc = 0; 925 if (base < NDADDR) { 926 for ( ; loc < NDADDR; loc++) { 927 if (ffs_isblock(fs, cg_blksfree(cgp), loc)) 928 DIP_SET(ip, i_db[loc], BLK_NOCOPY); 929 else if (passno == 2 && DIP(ip, i_db[loc])== BLK_NOCOPY) 930 DIP_SET(ip, i_db[loc], 0); 931 else if (passno == 1 && DIP(ip, i_db[loc])== BLK_NOCOPY) 932 panic("ffs_snapshot: lost direct block"); 933 } 934 } 935 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)(base + loc)), 936 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp); 937 if (error) { 938 return (error); 939 } 940 indiroff = (base + loc - NDADDR) % NINDIR(fs); 941 for ( ; loc < len; loc++, indiroff++) { 942 if (indiroff >= NINDIR(fs)) { 943 if (passno == 2) 944 ibp->b_flags |= B_VALIDSUSPWRT; 945 bawrite(ibp); 946 error = UFS_BALLOC(vp, 947 lblktosize(fs, (off_t)(base + loc)), 948 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp); 949 if (error) { 950 return (error); 951 } 952 indiroff = 0; 953 } 954 if (ip->i_ump->um_fstype == UFS1) { 955 if (ffs_isblock(fs, cg_blksfree(cgp), loc)) 956 ((ufs1_daddr_t *)(ibp->b_data))[indiroff] = 957 BLK_NOCOPY; 958 else if (passno == 2 && ((ufs1_daddr_t *)(ibp->b_data)) 959 [indiroff] == BLK_NOCOPY) 960 ((ufs1_daddr_t *)(ibp->b_data))[indiroff] = 0; 961 else if (passno == 1 && ((ufs1_daddr_t *)(ibp->b_data)) 962 [indiroff] == BLK_NOCOPY) 963 panic("ffs_snapshot: lost indirect block"); 964 continue; 965 } 966 if (ffs_isblock(fs, cg_blksfree(cgp), loc)) 967 ((ufs2_daddr_t *)(ibp->b_data))[indiroff] = BLK_NOCOPY; 968 else if (passno == 2 && 969 ((ufs2_daddr_t *)(ibp->b_data)) [indiroff] == BLK_NOCOPY) 970 ((ufs2_daddr_t *)(ibp->b_data))[indiroff] = 0; 971 else if (passno == 1 && 972 ((ufs2_daddr_t *)(ibp->b_data)) [indiroff] == BLK_NOCOPY) 973 panic("ffs_snapshot: lost indirect block"); 974 } 975 if (passno == 2) 976 ibp->b_flags |= B_VALIDSUSPWRT; 977 bdwrite(ibp); 978 return (0); 979 } 980 981 /* 982 * Before expunging a snapshot inode, note all the 983 * blocks that it claims with BLK_SNAP so that fsck will 984 * be able to account for those blocks properly and so 985 * that this snapshot knows that it need not copy them 986 * if the other snapshot holding them is freed. This code 987 * is reproduced once each for UFS1 and UFS2. 988 */ 989 static int 990 expunge_ufs1(snapvp, cancelip, fs, acctfunc, expungetype, clearmode) 991 struct vnode *snapvp; 992 struct inode *cancelip; 993 struct fs *fs; 994 int (*acctfunc)(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *, 995 struct fs *, ufs_lbn_t, int); 996 int expungetype; 997 int clearmode; 998 { 999 int i, error, indiroff; 1000 ufs_lbn_t lbn, rlbn; 1001 ufs2_daddr_t len, blkno, numblks, blksperindir; 1002 struct ufs1_dinode *dip; 1003 struct thread *td = curthread; 1004 struct buf *bp; 1005 1006 /* 1007 * Prepare to expunge the inode. If its inode block has not 1008 * yet been copied, then allocate and fill the copy. 1009 */ 1010 lbn = fragstoblks(fs, ino_to_fsba(fs, cancelip->i_number)); 1011 blkno = 0; 1012 if (lbn < NDADDR) { 1013 blkno = VTOI(snapvp)->i_din1->di_db[lbn]; 1014 } else { 1015 if (DOINGSOFTDEP(snapvp)) 1016 softdep_prealloc(snapvp, MNT_WAIT); 1017 td->td_pflags |= TDP_COWINPROGRESS; 1018 error = ffs_balloc_ufs1(snapvp, lblktosize(fs, (off_t)lbn), 1019 fs->fs_bsize, KERNCRED, BA_METAONLY, &bp); 1020 td->td_pflags &= ~TDP_COWINPROGRESS; 1021 if (error) 1022 return (error); 1023 indiroff = (lbn - NDADDR) % NINDIR(fs); 1024 blkno = ((ufs1_daddr_t *)(bp->b_data))[indiroff]; 1025 bqrelse(bp); 1026 } 1027 if (blkno != 0) { 1028 if ((error = bread(snapvp, lbn, fs->fs_bsize, KERNCRED, &bp))) 1029 return (error); 1030 } else { 1031 error = ffs_balloc_ufs1(snapvp, lblktosize(fs, (off_t)lbn), 1032 fs->fs_bsize, KERNCRED, 0, &bp); 1033 if (error) 1034 return (error); 1035 if ((error = readblock(snapvp, bp, lbn)) != 0) 1036 return (error); 1037 } 1038 /* 1039 * Set a snapshot inode to be a zero length file, regular files 1040 * or unlinked snapshots to be completely unallocated. 1041 */ 1042 dip = (struct ufs1_dinode *)bp->b_data + 1043 ino_to_fsbo(fs, cancelip->i_number); 1044 if (clearmode || cancelip->i_effnlink == 0) 1045 dip->di_mode = 0; 1046 dip->di_size = 0; 1047 dip->di_blocks = 0; 1048 dip->di_flags &= ~SF_SNAPSHOT; 1049 bzero(&dip->di_db[0], (NDADDR + NIADDR) * sizeof(ufs1_daddr_t)); 1050 bdwrite(bp); 1051 /* 1052 * Now go through and expunge all the blocks in the file 1053 * using the function requested. 1054 */ 1055 numblks = howmany(cancelip->i_size, fs->fs_bsize); 1056 if ((error = (*acctfunc)(snapvp, &cancelip->i_din1->di_db[0], 1057 &cancelip->i_din1->di_db[NDADDR], fs, 0, expungetype))) 1058 return (error); 1059 if ((error = (*acctfunc)(snapvp, &cancelip->i_din1->di_ib[0], 1060 &cancelip->i_din1->di_ib[NIADDR], fs, -1, expungetype))) 1061 return (error); 1062 blksperindir = 1; 1063 lbn = -NDADDR; 1064 len = numblks - NDADDR; 1065 rlbn = NDADDR; 1066 for (i = 0; len > 0 && i < NIADDR; i++) { 1067 error = indiracct_ufs1(snapvp, ITOV(cancelip), i, 1068 cancelip->i_din1->di_ib[i], lbn, rlbn, len, 1069 blksperindir, fs, acctfunc, expungetype); 1070 if (error) 1071 return (error); 1072 blksperindir *= NINDIR(fs); 1073 lbn -= blksperindir + 1; 1074 len -= blksperindir; 1075 rlbn += blksperindir; 1076 } 1077 return (0); 1078 } 1079 1080 /* 1081 * Descend an indirect block chain for vnode cancelvp accounting for all 1082 * its indirect blocks in snapvp. 1083 */ 1084 static int 1085 indiracct_ufs1(snapvp, cancelvp, level, blkno, lbn, rlbn, remblks, 1086 blksperindir, fs, acctfunc, expungetype) 1087 struct vnode *snapvp; 1088 struct vnode *cancelvp; 1089 int level; 1090 ufs1_daddr_t blkno; 1091 ufs_lbn_t lbn; 1092 ufs_lbn_t rlbn; 1093 ufs_lbn_t remblks; 1094 ufs_lbn_t blksperindir; 1095 struct fs *fs; 1096 int (*acctfunc)(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *, 1097 struct fs *, ufs_lbn_t, int); 1098 int expungetype; 1099 { 1100 int error, num, i; 1101 ufs_lbn_t subblksperindir; 1102 struct indir indirs[NIADDR + 2]; 1103 ufs1_daddr_t last, *bap; 1104 struct buf *bp; 1105 1106 if (blkno == 0) { 1107 if (expungetype == BLK_NOCOPY) 1108 return (0); 1109 panic("indiracct_ufs1: missing indir"); 1110 } 1111 if ((error = ufs_getlbns(cancelvp, rlbn, indirs, &num)) != 0) 1112 return (error); 1113 if (lbn != indirs[num - 1 - level].in_lbn || num < 2) 1114 panic("indiracct_ufs1: botched params"); 1115 /* 1116 * We have to expand bread here since it will deadlock looking 1117 * up the block number for any blocks that are not in the cache. 1118 */ 1119 bp = getblk(cancelvp, lbn, fs->fs_bsize, 0, 0, 0); 1120 bp->b_blkno = fsbtodb(fs, blkno); 1121 if ((bp->b_flags & (B_DONE | B_DELWRI)) == 0 && 1122 (error = readblock(cancelvp, bp, fragstoblks(fs, blkno)))) { 1123 brelse(bp); 1124 return (error); 1125 } 1126 /* 1127 * Account for the block pointers in this indirect block. 1128 */ 1129 last = howmany(remblks, blksperindir); 1130 if (last > NINDIR(fs)) 1131 last = NINDIR(fs); 1132 bap = malloc(fs->fs_bsize, M_DEVBUF, M_WAITOK); 1133 bcopy(bp->b_data, (caddr_t)bap, fs->fs_bsize); 1134 bqrelse(bp); 1135 error = (*acctfunc)(snapvp, &bap[0], &bap[last], fs, 1136 level == 0 ? rlbn : -1, expungetype); 1137 if (error || level == 0) 1138 goto out; 1139 /* 1140 * Account for the block pointers in each of the indirect blocks 1141 * in the levels below us. 1142 */ 1143 subblksperindir = blksperindir / NINDIR(fs); 1144 for (lbn++, level--, i = 0; i < last; i++) { 1145 error = indiracct_ufs1(snapvp, cancelvp, level, bap[i], lbn, 1146 rlbn, remblks, subblksperindir, fs, acctfunc, expungetype); 1147 if (error) 1148 goto out; 1149 rlbn += blksperindir; 1150 lbn -= blksperindir; 1151 remblks -= blksperindir; 1152 } 1153 out: 1154 free(bap, M_DEVBUF); 1155 return (error); 1156 } 1157 1158 /* 1159 * Do both snap accounting and map accounting. 1160 */ 1161 static int 1162 fullacct_ufs1(vp, oldblkp, lastblkp, fs, lblkno, exptype) 1163 struct vnode *vp; 1164 ufs1_daddr_t *oldblkp, *lastblkp; 1165 struct fs *fs; 1166 ufs_lbn_t lblkno; 1167 int exptype; /* BLK_SNAP or BLK_NOCOPY */ 1168 { 1169 int error; 1170 1171 if ((error = snapacct_ufs1(vp, oldblkp, lastblkp, fs, lblkno, exptype))) 1172 return (error); 1173 return (mapacct_ufs1(vp, oldblkp, lastblkp, fs, lblkno, exptype)); 1174 } 1175 1176 /* 1177 * Identify a set of blocks allocated in a snapshot inode. 1178 */ 1179 static int 1180 snapacct_ufs1(vp, oldblkp, lastblkp, fs, lblkno, expungetype) 1181 struct vnode *vp; 1182 ufs1_daddr_t *oldblkp, *lastblkp; 1183 struct fs *fs; 1184 ufs_lbn_t lblkno; 1185 int expungetype; /* BLK_SNAP or BLK_NOCOPY */ 1186 { 1187 struct inode *ip = VTOI(vp); 1188 ufs1_daddr_t blkno, *blkp; 1189 ufs_lbn_t lbn; 1190 struct buf *ibp; 1191 int error; 1192 1193 for ( ; oldblkp < lastblkp; oldblkp++) { 1194 blkno = *oldblkp; 1195 if (blkno == 0 || blkno == BLK_NOCOPY || blkno == BLK_SNAP) 1196 continue; 1197 lbn = fragstoblks(fs, blkno); 1198 if (lbn < NDADDR) { 1199 blkp = &ip->i_din1->di_db[lbn]; 1200 ip->i_flag |= IN_CHANGE | IN_UPDATE; 1201 } else { 1202 error = ffs_balloc_ufs1(vp, lblktosize(fs, (off_t)lbn), 1203 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp); 1204 if (error) 1205 return (error); 1206 blkp = &((ufs1_daddr_t *)(ibp->b_data)) 1207 [(lbn - NDADDR) % NINDIR(fs)]; 1208 } 1209 /* 1210 * If we are expunging a snapshot vnode and we 1211 * find a block marked BLK_NOCOPY, then it is 1212 * one that has been allocated to this snapshot after 1213 * we took our current snapshot and can be ignored. 1214 */ 1215 if (expungetype == BLK_SNAP && *blkp == BLK_NOCOPY) { 1216 if (lbn >= NDADDR) 1217 brelse(ibp); 1218 } else { 1219 if (*blkp != 0) 1220 panic("snapacct_ufs1: bad block"); 1221 *blkp = expungetype; 1222 if (lbn >= NDADDR) 1223 bdwrite(ibp); 1224 } 1225 } 1226 return (0); 1227 } 1228 1229 /* 1230 * Account for a set of blocks allocated in a snapshot inode. 1231 */ 1232 static int 1233 mapacct_ufs1(vp, oldblkp, lastblkp, fs, lblkno, expungetype) 1234 struct vnode *vp; 1235 ufs1_daddr_t *oldblkp, *lastblkp; 1236 struct fs *fs; 1237 ufs_lbn_t lblkno; 1238 int expungetype; 1239 { 1240 ufs1_daddr_t blkno; 1241 struct inode *ip; 1242 ino_t inum; 1243 int acctit; 1244 1245 ip = VTOI(vp); 1246 inum = ip->i_number; 1247 if (lblkno == -1) 1248 acctit = 0; 1249 else 1250 acctit = 1; 1251 for ( ; oldblkp < lastblkp; oldblkp++, lblkno++) { 1252 blkno = *oldblkp; 1253 if (blkno == 0 || blkno == BLK_NOCOPY) 1254 continue; 1255 if (acctit && expungetype == BLK_SNAP && blkno != BLK_SNAP) 1256 *ip->i_snapblklist++ = lblkno; 1257 if (blkno == BLK_SNAP) 1258 blkno = blkstofrags(fs, lblkno); 1259 ffs_blkfree(ip->i_ump, fs, vp, blkno, fs->fs_bsize, inum, 1260 vp->v_type, NULL); 1261 } 1262 return (0); 1263 } 1264 1265 /* 1266 * Before expunging a snapshot inode, note all the 1267 * blocks that it claims with BLK_SNAP so that fsck will 1268 * be able to account for those blocks properly and so 1269 * that this snapshot knows that it need not copy them 1270 * if the other snapshot holding them is freed. This code 1271 * is reproduced once each for UFS1 and UFS2. 1272 */ 1273 static int 1274 expunge_ufs2(snapvp, cancelip, fs, acctfunc, expungetype, clearmode) 1275 struct vnode *snapvp; 1276 struct inode *cancelip; 1277 struct fs *fs; 1278 int (*acctfunc)(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *, 1279 struct fs *, ufs_lbn_t, int); 1280 int expungetype; 1281 int clearmode; 1282 { 1283 int i, error, indiroff; 1284 ufs_lbn_t lbn, rlbn; 1285 ufs2_daddr_t len, blkno, numblks, blksperindir; 1286 struct ufs2_dinode *dip; 1287 struct thread *td = curthread; 1288 struct buf *bp; 1289 1290 /* 1291 * Prepare to expunge the inode. If its inode block has not 1292 * yet been copied, then allocate and fill the copy. 1293 */ 1294 lbn = fragstoblks(fs, ino_to_fsba(fs, cancelip->i_number)); 1295 blkno = 0; 1296 if (lbn < NDADDR) { 1297 blkno = VTOI(snapvp)->i_din2->di_db[lbn]; 1298 } else { 1299 if (DOINGSOFTDEP(snapvp)) 1300 softdep_prealloc(snapvp, MNT_WAIT); 1301 td->td_pflags |= TDP_COWINPROGRESS; 1302 error = ffs_balloc_ufs2(snapvp, lblktosize(fs, (off_t)lbn), 1303 fs->fs_bsize, KERNCRED, BA_METAONLY, &bp); 1304 td->td_pflags &= ~TDP_COWINPROGRESS; 1305 if (error) 1306 return (error); 1307 indiroff = (lbn - NDADDR) % NINDIR(fs); 1308 blkno = ((ufs2_daddr_t *)(bp->b_data))[indiroff]; 1309 bqrelse(bp); 1310 } 1311 if (blkno != 0) { 1312 if ((error = bread(snapvp, lbn, fs->fs_bsize, KERNCRED, &bp))) 1313 return (error); 1314 } else { 1315 error = ffs_balloc_ufs2(snapvp, lblktosize(fs, (off_t)lbn), 1316 fs->fs_bsize, KERNCRED, 0, &bp); 1317 if (error) 1318 return (error); 1319 if ((error = readblock(snapvp, bp, lbn)) != 0) 1320 return (error); 1321 } 1322 /* 1323 * Set a snapshot inode to be a zero length file, regular files 1324 * to be completely unallocated. 1325 */ 1326 dip = (struct ufs2_dinode *)bp->b_data + 1327 ino_to_fsbo(fs, cancelip->i_number); 1328 if (clearmode || cancelip->i_effnlink == 0) 1329 dip->di_mode = 0; 1330 dip->di_size = 0; 1331 dip->di_blocks = 0; 1332 dip->di_flags &= ~SF_SNAPSHOT; 1333 bzero(&dip->di_db[0], (NDADDR + NIADDR) * sizeof(ufs2_daddr_t)); 1334 bdwrite(bp); 1335 /* 1336 * Now go through and expunge all the blocks in the file 1337 * using the function requested. 1338 */ 1339 numblks = howmany(cancelip->i_size, fs->fs_bsize); 1340 if ((error = (*acctfunc)(snapvp, &cancelip->i_din2->di_db[0], 1341 &cancelip->i_din2->di_db[NDADDR], fs, 0, expungetype))) 1342 return (error); 1343 if ((error = (*acctfunc)(snapvp, &cancelip->i_din2->di_ib[0], 1344 &cancelip->i_din2->di_ib[NIADDR], fs, -1, expungetype))) 1345 return (error); 1346 blksperindir = 1; 1347 lbn = -NDADDR; 1348 len = numblks - NDADDR; 1349 rlbn = NDADDR; 1350 for (i = 0; len > 0 && i < NIADDR; i++) { 1351 error = indiracct_ufs2(snapvp, ITOV(cancelip), i, 1352 cancelip->i_din2->di_ib[i], lbn, rlbn, len, 1353 blksperindir, fs, acctfunc, expungetype); 1354 if (error) 1355 return (error); 1356 blksperindir *= NINDIR(fs); 1357 lbn -= blksperindir + 1; 1358 len -= blksperindir; 1359 rlbn += blksperindir; 1360 } 1361 return (0); 1362 } 1363 1364 /* 1365 * Descend an indirect block chain for vnode cancelvp accounting for all 1366 * its indirect blocks in snapvp. 1367 */ 1368 static int 1369 indiracct_ufs2(snapvp, cancelvp, level, blkno, lbn, rlbn, remblks, 1370 blksperindir, fs, acctfunc, expungetype) 1371 struct vnode *snapvp; 1372 struct vnode *cancelvp; 1373 int level; 1374 ufs2_daddr_t blkno; 1375 ufs_lbn_t lbn; 1376 ufs_lbn_t rlbn; 1377 ufs_lbn_t remblks; 1378 ufs_lbn_t blksperindir; 1379 struct fs *fs; 1380 int (*acctfunc)(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *, 1381 struct fs *, ufs_lbn_t, int); 1382 int expungetype; 1383 { 1384 int error, num, i; 1385 ufs_lbn_t subblksperindir; 1386 struct indir indirs[NIADDR + 2]; 1387 ufs2_daddr_t last, *bap; 1388 struct buf *bp; 1389 1390 if (blkno == 0) { 1391 if (expungetype == BLK_NOCOPY) 1392 return (0); 1393 panic("indiracct_ufs2: missing indir"); 1394 } 1395 if ((error = ufs_getlbns(cancelvp, rlbn, indirs, &num)) != 0) 1396 return (error); 1397 if (lbn != indirs[num - 1 - level].in_lbn || num < 2) 1398 panic("indiracct_ufs2: botched params"); 1399 /* 1400 * We have to expand bread here since it will deadlock looking 1401 * up the block number for any blocks that are not in the cache. 1402 */ 1403 bp = getblk(cancelvp, lbn, fs->fs_bsize, 0, 0, 0); 1404 bp->b_blkno = fsbtodb(fs, blkno); 1405 if ((bp->b_flags & (B_DONE | B_DELWRI)) == 0 && 1406 (error = readblock(cancelvp, bp, fragstoblks(fs, blkno)))) { 1407 brelse(bp); 1408 return (error); 1409 } 1410 /* 1411 * Account for the block pointers in this indirect block. 1412 */ 1413 last = howmany(remblks, blksperindir); 1414 if (last > NINDIR(fs)) 1415 last = NINDIR(fs); 1416 bap = malloc(fs->fs_bsize, M_DEVBUF, M_WAITOK); 1417 bcopy(bp->b_data, (caddr_t)bap, fs->fs_bsize); 1418 bqrelse(bp); 1419 error = (*acctfunc)(snapvp, &bap[0], &bap[last], fs, 1420 level == 0 ? rlbn : -1, expungetype); 1421 if (error || level == 0) 1422 goto out; 1423 /* 1424 * Account for the block pointers in each of the indirect blocks 1425 * in the levels below us. 1426 */ 1427 subblksperindir = blksperindir / NINDIR(fs); 1428 for (lbn++, level--, i = 0; i < last; i++) { 1429 error = indiracct_ufs2(snapvp, cancelvp, level, bap[i], lbn, 1430 rlbn, remblks, subblksperindir, fs, acctfunc, expungetype); 1431 if (error) 1432 goto out; 1433 rlbn += blksperindir; 1434 lbn -= blksperindir; 1435 remblks -= blksperindir; 1436 } 1437 out: 1438 free(bap, M_DEVBUF); 1439 return (error); 1440 } 1441 1442 /* 1443 * Do both snap accounting and map accounting. 1444 */ 1445 static int 1446 fullacct_ufs2(vp, oldblkp, lastblkp, fs, lblkno, exptype) 1447 struct vnode *vp; 1448 ufs2_daddr_t *oldblkp, *lastblkp; 1449 struct fs *fs; 1450 ufs_lbn_t lblkno; 1451 int exptype; /* BLK_SNAP or BLK_NOCOPY */ 1452 { 1453 int error; 1454 1455 if ((error = snapacct_ufs2(vp, oldblkp, lastblkp, fs, lblkno, exptype))) 1456 return (error); 1457 return (mapacct_ufs2(vp, oldblkp, lastblkp, fs, lblkno, exptype)); 1458 } 1459 1460 /* 1461 * Identify a set of blocks allocated in a snapshot inode. 1462 */ 1463 static int 1464 snapacct_ufs2(vp, oldblkp, lastblkp, fs, lblkno, expungetype) 1465 struct vnode *vp; 1466 ufs2_daddr_t *oldblkp, *lastblkp; 1467 struct fs *fs; 1468 ufs_lbn_t lblkno; 1469 int expungetype; /* BLK_SNAP or BLK_NOCOPY */ 1470 { 1471 struct inode *ip = VTOI(vp); 1472 ufs2_daddr_t blkno, *blkp; 1473 ufs_lbn_t lbn; 1474 struct buf *ibp; 1475 int error; 1476 1477 for ( ; oldblkp < lastblkp; oldblkp++) { 1478 blkno = *oldblkp; 1479 if (blkno == 0 || blkno == BLK_NOCOPY || blkno == BLK_SNAP) 1480 continue; 1481 lbn = fragstoblks(fs, blkno); 1482 if (lbn < NDADDR) { 1483 blkp = &ip->i_din2->di_db[lbn]; 1484 ip->i_flag |= IN_CHANGE | IN_UPDATE; 1485 } else { 1486 error = ffs_balloc_ufs2(vp, lblktosize(fs, (off_t)lbn), 1487 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp); 1488 if (error) 1489 return (error); 1490 blkp = &((ufs2_daddr_t *)(ibp->b_data)) 1491 [(lbn - NDADDR) % NINDIR(fs)]; 1492 } 1493 /* 1494 * If we are expunging a snapshot vnode and we 1495 * find a block marked BLK_NOCOPY, then it is 1496 * one that has been allocated to this snapshot after 1497 * we took our current snapshot and can be ignored. 1498 */ 1499 if (expungetype == BLK_SNAP && *blkp == BLK_NOCOPY) { 1500 if (lbn >= NDADDR) 1501 brelse(ibp); 1502 } else { 1503 if (*blkp != 0) 1504 panic("snapacct_ufs2: bad block"); 1505 *blkp = expungetype; 1506 if (lbn >= NDADDR) 1507 bdwrite(ibp); 1508 } 1509 } 1510 return (0); 1511 } 1512 1513 /* 1514 * Account for a set of blocks allocated in a snapshot inode. 1515 */ 1516 static int 1517 mapacct_ufs2(vp, oldblkp, lastblkp, fs, lblkno, expungetype) 1518 struct vnode *vp; 1519 ufs2_daddr_t *oldblkp, *lastblkp; 1520 struct fs *fs; 1521 ufs_lbn_t lblkno; 1522 int expungetype; 1523 { 1524 ufs2_daddr_t blkno; 1525 struct inode *ip; 1526 ino_t inum; 1527 int acctit; 1528 1529 ip = VTOI(vp); 1530 inum = ip->i_number; 1531 if (lblkno == -1) 1532 acctit = 0; 1533 else 1534 acctit = 1; 1535 for ( ; oldblkp < lastblkp; oldblkp++, lblkno++) { 1536 blkno = *oldblkp; 1537 if (blkno == 0 || blkno == BLK_NOCOPY) 1538 continue; 1539 if (acctit && expungetype == BLK_SNAP && blkno != BLK_SNAP) 1540 *ip->i_snapblklist++ = lblkno; 1541 if (blkno == BLK_SNAP) 1542 blkno = blkstofrags(fs, lblkno); 1543 ffs_blkfree(ip->i_ump, fs, vp, blkno, fs->fs_bsize, inum, 1544 vp->v_type, NULL); 1545 } 1546 return (0); 1547 } 1548 1549 /* 1550 * Decrement extra reference on snapshot when last name is removed. 1551 * It will not be freed until the last open reference goes away. 1552 */ 1553 void 1554 ffs_snapgone(ip) 1555 struct inode *ip; 1556 { 1557 struct inode *xp; 1558 struct fs *fs; 1559 int snaploc; 1560 struct snapdata *sn; 1561 struct ufsmount *ump; 1562 1563 /* 1564 * Find snapshot in incore list. 1565 */ 1566 xp = NULL; 1567 sn = ip->i_devvp->v_rdev->si_snapdata; 1568 if (sn != NULL) 1569 TAILQ_FOREACH(xp, &sn->sn_head, i_nextsnap) 1570 if (xp == ip) 1571 break; 1572 if (xp != NULL) 1573 vrele(ITOV(ip)); 1574 else if (snapdebug) 1575 printf("ffs_snapgone: lost snapshot vnode %ju\n", 1576 (uintmax_t)ip->i_number); 1577 /* 1578 * Delete snapshot inode from superblock. Keep list dense. 1579 */ 1580 fs = ip->i_fs; 1581 ump = ip->i_ump; 1582 UFS_LOCK(ump); 1583 for (snaploc = 0; snaploc < FSMAXSNAP; snaploc++) 1584 if (fs->fs_snapinum[snaploc] == ip->i_number) 1585 break; 1586 if (snaploc < FSMAXSNAP) { 1587 for (snaploc++; snaploc < FSMAXSNAP; snaploc++) { 1588 if (fs->fs_snapinum[snaploc] == 0) 1589 break; 1590 fs->fs_snapinum[snaploc - 1] = fs->fs_snapinum[snaploc]; 1591 } 1592 fs->fs_snapinum[snaploc - 1] = 0; 1593 } 1594 UFS_UNLOCK(ump); 1595 } 1596 1597 /* 1598 * Prepare a snapshot file for being removed. 1599 */ 1600 void 1601 ffs_snapremove(vp) 1602 struct vnode *vp; 1603 { 1604 struct inode *ip; 1605 struct vnode *devvp; 1606 struct buf *ibp; 1607 struct fs *fs; 1608 ufs2_daddr_t numblks, blkno, dblk; 1609 int error, loc, last; 1610 struct snapdata *sn; 1611 1612 ip = VTOI(vp); 1613 fs = ip->i_fs; 1614 devvp = ip->i_devvp; 1615 /* 1616 * If active, delete from incore list (this snapshot may 1617 * already have been in the process of being deleted, so 1618 * would not have been active). 1619 * 1620 * Clear copy-on-write flag if last snapshot. 1621 */ 1622 VI_LOCK(devvp); 1623 if (ip->i_nextsnap.tqe_prev != 0) { 1624 sn = devvp->v_rdev->si_snapdata; 1625 TAILQ_REMOVE(&sn->sn_head, ip, i_nextsnap); 1626 ip->i_nextsnap.tqe_prev = 0; 1627 VI_UNLOCK(devvp); 1628 lockmgr(&vp->v_lock, LK_EXCLUSIVE, NULL); 1629 KASSERT(vp->v_vnlock == &sn->sn_lock, 1630 ("ffs_snapremove: lost lock mutation")); 1631 vp->v_vnlock = &vp->v_lock; 1632 VI_LOCK(devvp); 1633 lockmgr(&sn->sn_lock, LK_RELEASE, NULL); 1634 try_free_snapdata(devvp); 1635 } else 1636 VI_UNLOCK(devvp); 1637 /* 1638 * Clear all BLK_NOCOPY fields. Pass any block claims to other 1639 * snapshots that want them (see ffs_snapblkfree below). 1640 */ 1641 for (blkno = 1; blkno < NDADDR; blkno++) { 1642 dblk = DIP(ip, i_db[blkno]); 1643 if (dblk == 0) 1644 continue; 1645 if (dblk == BLK_NOCOPY || dblk == BLK_SNAP) 1646 DIP_SET(ip, i_db[blkno], 0); 1647 else if ((dblk == blkstofrags(fs, blkno) && 1648 ffs_snapblkfree(fs, ip->i_devvp, dblk, fs->fs_bsize, 1649 ip->i_number, vp->v_type, NULL))) { 1650 DIP_SET(ip, i_blocks, DIP(ip, i_blocks) - 1651 btodb(fs->fs_bsize)); 1652 DIP_SET(ip, i_db[blkno], 0); 1653 } 1654 } 1655 numblks = howmany(ip->i_size, fs->fs_bsize); 1656 for (blkno = NDADDR; blkno < numblks; blkno += NINDIR(fs)) { 1657 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)blkno), 1658 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp); 1659 if (error) 1660 continue; 1661 if (fs->fs_size - blkno > NINDIR(fs)) 1662 last = NINDIR(fs); 1663 else 1664 last = fs->fs_size - blkno; 1665 for (loc = 0; loc < last; loc++) { 1666 if (ip->i_ump->um_fstype == UFS1) { 1667 dblk = ((ufs1_daddr_t *)(ibp->b_data))[loc]; 1668 if (dblk == 0) 1669 continue; 1670 if (dblk == BLK_NOCOPY || dblk == BLK_SNAP) 1671 ((ufs1_daddr_t *)(ibp->b_data))[loc]= 0; 1672 else if ((dblk == blkstofrags(fs, blkno) && 1673 ffs_snapblkfree(fs, ip->i_devvp, dblk, 1674 fs->fs_bsize, ip->i_number, vp->v_type, 1675 NULL))) { 1676 ip->i_din1->di_blocks -= 1677 btodb(fs->fs_bsize); 1678 ((ufs1_daddr_t *)(ibp->b_data))[loc]= 0; 1679 } 1680 continue; 1681 } 1682 dblk = ((ufs2_daddr_t *)(ibp->b_data))[loc]; 1683 if (dblk == 0) 1684 continue; 1685 if (dblk == BLK_NOCOPY || dblk == BLK_SNAP) 1686 ((ufs2_daddr_t *)(ibp->b_data))[loc] = 0; 1687 else if ((dblk == blkstofrags(fs, blkno) && 1688 ffs_snapblkfree(fs, ip->i_devvp, dblk, 1689 fs->fs_bsize, ip->i_number, vp->v_type, NULL))) { 1690 ip->i_din2->di_blocks -= btodb(fs->fs_bsize); 1691 ((ufs2_daddr_t *)(ibp->b_data))[loc] = 0; 1692 } 1693 } 1694 bawrite(ibp); 1695 } 1696 /* 1697 * Clear snapshot flag and drop reference. 1698 */ 1699 ip->i_flags &= ~SF_SNAPSHOT; 1700 DIP_SET(ip, i_flags, ip->i_flags); 1701 ip->i_flag |= IN_CHANGE | IN_UPDATE; 1702 /* 1703 * The dirtied indirects must be written out before 1704 * softdep_setup_freeblocks() is called. Otherwise indir_trunc() 1705 * may find indirect pointers using the magic BLK_* values. 1706 */ 1707 if (DOINGSOFTDEP(vp)) 1708 ffs_syncvnode(vp, MNT_WAIT, 0); 1709 #ifdef QUOTA 1710 /* 1711 * Reenable disk quotas for ex-snapshot file. 1712 */ 1713 if (!getinoquota(ip)) 1714 (void) chkdq(ip, DIP(ip, i_blocks), KERNCRED, FORCE); 1715 #endif 1716 } 1717 1718 /* 1719 * Notification that a block is being freed. Return zero if the free 1720 * should be allowed to proceed. Return non-zero if the snapshot file 1721 * wants to claim the block. The block will be claimed if it is an 1722 * uncopied part of one of the snapshots. It will be freed if it is 1723 * either a BLK_NOCOPY or has already been copied in all of the snapshots. 1724 * If a fragment is being freed, then all snapshots that care about 1725 * it must make a copy since a snapshot file can only claim full sized 1726 * blocks. Note that if more than one snapshot file maps the block, 1727 * we can pick one at random to claim it. Since none of the snapshots 1728 * can change, we are assurred that they will all see the same unmodified 1729 * image. When deleting a snapshot file (see ffs_snapremove above), we 1730 * must push any of these claimed blocks to one of the other snapshots 1731 * that maps it. These claimed blocks are easily identified as they will 1732 * have a block number equal to their logical block number within the 1733 * snapshot. A copied block can never have this property because they 1734 * must always have been allocated from a BLK_NOCOPY location. 1735 */ 1736 int 1737 ffs_snapblkfree(fs, devvp, bno, size, inum, vtype, wkhd) 1738 struct fs *fs; 1739 struct vnode *devvp; 1740 ufs2_daddr_t bno; 1741 long size; 1742 ino_t inum; 1743 enum vtype vtype; 1744 struct workhead *wkhd; 1745 { 1746 struct buf *ibp, *cbp, *savedcbp = NULL; 1747 struct thread *td = curthread; 1748 struct inode *ip; 1749 struct vnode *vp = NULL; 1750 ufs_lbn_t lbn; 1751 ufs2_daddr_t blkno; 1752 int indiroff = 0, error = 0, claimedblk = 0; 1753 struct snapdata *sn; 1754 1755 lbn = fragstoblks(fs, bno); 1756 retry: 1757 VI_LOCK(devvp); 1758 sn = devvp->v_rdev->si_snapdata; 1759 if (sn == NULL) { 1760 VI_UNLOCK(devvp); 1761 return (0); 1762 } 1763 if (lockmgr(&sn->sn_lock, LK_INTERLOCK | LK_EXCLUSIVE | LK_SLEEPFAIL, 1764 VI_MTX(devvp)) != 0) 1765 goto retry; 1766 TAILQ_FOREACH(ip, &sn->sn_head, i_nextsnap) { 1767 vp = ITOV(ip); 1768 if (DOINGSOFTDEP(vp)) 1769 softdep_prealloc(vp, MNT_WAIT); 1770 /* 1771 * Lookup block being written. 1772 */ 1773 if (lbn < NDADDR) { 1774 blkno = DIP(ip, i_db[lbn]); 1775 } else { 1776 td->td_pflags |= TDP_COWINPROGRESS; 1777 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)lbn), 1778 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp); 1779 td->td_pflags &= ~TDP_COWINPROGRESS; 1780 if (error) 1781 break; 1782 indiroff = (lbn - NDADDR) % NINDIR(fs); 1783 if (ip->i_ump->um_fstype == UFS1) 1784 blkno=((ufs1_daddr_t *)(ibp->b_data))[indiroff]; 1785 else 1786 blkno=((ufs2_daddr_t *)(ibp->b_data))[indiroff]; 1787 } 1788 /* 1789 * Check to see if block needs to be copied. 1790 */ 1791 if (blkno == 0) { 1792 /* 1793 * A block that we map is being freed. If it has not 1794 * been claimed yet, we will claim or copy it (below). 1795 */ 1796 claimedblk = 1; 1797 } else if (blkno == BLK_SNAP) { 1798 /* 1799 * No previous snapshot claimed the block, 1800 * so it will be freed and become a BLK_NOCOPY 1801 * (don't care) for us. 1802 */ 1803 if (claimedblk) 1804 panic("snapblkfree: inconsistent block type"); 1805 if (lbn < NDADDR) { 1806 DIP_SET(ip, i_db[lbn], BLK_NOCOPY); 1807 ip->i_flag |= IN_CHANGE | IN_UPDATE; 1808 } else if (ip->i_ump->um_fstype == UFS1) { 1809 ((ufs1_daddr_t *)(ibp->b_data))[indiroff] = 1810 BLK_NOCOPY; 1811 bdwrite(ibp); 1812 } else { 1813 ((ufs2_daddr_t *)(ibp->b_data))[indiroff] = 1814 BLK_NOCOPY; 1815 bdwrite(ibp); 1816 } 1817 continue; 1818 } else /* BLK_NOCOPY or default */ { 1819 /* 1820 * If the snapshot has already copied the block 1821 * (default), or does not care about the block, 1822 * it is not needed. 1823 */ 1824 if (lbn >= NDADDR) 1825 bqrelse(ibp); 1826 continue; 1827 } 1828 /* 1829 * If this is a full size block, we will just grab it 1830 * and assign it to the snapshot inode. Otherwise we 1831 * will proceed to copy it. See explanation for this 1832 * routine as to why only a single snapshot needs to 1833 * claim this block. 1834 */ 1835 if (size == fs->fs_bsize) { 1836 #ifdef DEBUG 1837 if (snapdebug) 1838 printf("%s %ju lbn %jd from inum %ju\n", 1839 "Grabonremove: snapino", 1840 (uintmax_t)ip->i_number, 1841 (intmax_t)lbn, (uintmax_t)inum); 1842 #endif 1843 /* 1844 * If journaling is tracking this write we must add 1845 * the work to the inode or indirect being written. 1846 */ 1847 if (wkhd != NULL) { 1848 if (lbn < NDADDR) 1849 softdep_inode_append(ip, 1850 curthread->td_ucred, wkhd); 1851 else 1852 softdep_buf_append(ibp, wkhd); 1853 } 1854 if (lbn < NDADDR) { 1855 DIP_SET(ip, i_db[lbn], bno); 1856 } else if (ip->i_ump->um_fstype == UFS1) { 1857 ((ufs1_daddr_t *)(ibp->b_data))[indiroff] = bno; 1858 bdwrite(ibp); 1859 } else { 1860 ((ufs2_daddr_t *)(ibp->b_data))[indiroff] = bno; 1861 bdwrite(ibp); 1862 } 1863 DIP_SET(ip, i_blocks, DIP(ip, i_blocks) + btodb(size)); 1864 ip->i_flag |= IN_CHANGE | IN_UPDATE; 1865 lockmgr(vp->v_vnlock, LK_RELEASE, NULL); 1866 return (1); 1867 } 1868 if (lbn >= NDADDR) 1869 bqrelse(ibp); 1870 /* 1871 * Allocate the block into which to do the copy. Note that this 1872 * allocation will never require any additional allocations for 1873 * the snapshot inode. 1874 */ 1875 td->td_pflags |= TDP_COWINPROGRESS; 1876 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)lbn), 1877 fs->fs_bsize, KERNCRED, 0, &cbp); 1878 td->td_pflags &= ~TDP_COWINPROGRESS; 1879 if (error) 1880 break; 1881 #ifdef DEBUG 1882 if (snapdebug) 1883 printf("%s%ju lbn %jd %s %ju size %ld to blkno %jd\n", 1884 "Copyonremove: snapino ", (uintmax_t)ip->i_number, 1885 (intmax_t)lbn, "for inum", (uintmax_t)inum, size, 1886 (intmax_t)cbp->b_blkno); 1887 #endif 1888 /* 1889 * If we have already read the old block contents, then 1890 * simply copy them to the new block. Note that we need 1891 * to synchronously write snapshots that have not been 1892 * unlinked, and hence will be visible after a crash, 1893 * to ensure their integrity. At a minimum we ensure the 1894 * integrity of the filesystem metadata, but use the 1895 * dopersistence sysctl-setable flag to decide on the 1896 * persistence needed for file content data. 1897 */ 1898 if (savedcbp != 0) { 1899 bcopy(savedcbp->b_data, cbp->b_data, fs->fs_bsize); 1900 bawrite(cbp); 1901 if ((vtype == VDIR || dopersistence) && 1902 ip->i_effnlink > 0) 1903 (void) ffs_syncvnode(vp, MNT_WAIT, NO_INO_UPDT); 1904 continue; 1905 } 1906 /* 1907 * Otherwise, read the old block contents into the buffer. 1908 */ 1909 if ((error = readblock(vp, cbp, lbn)) != 0) { 1910 bzero(cbp->b_data, fs->fs_bsize); 1911 bawrite(cbp); 1912 if ((vtype == VDIR || dopersistence) && 1913 ip->i_effnlink > 0) 1914 (void) ffs_syncvnode(vp, MNT_WAIT, NO_INO_UPDT); 1915 break; 1916 } 1917 savedcbp = cbp; 1918 } 1919 /* 1920 * Note that we need to synchronously write snapshots that 1921 * have not been unlinked, and hence will be visible after 1922 * a crash, to ensure their integrity. At a minimum we 1923 * ensure the integrity of the filesystem metadata, but 1924 * use the dopersistence sysctl-setable flag to decide on 1925 * the persistence needed for file content data. 1926 */ 1927 if (savedcbp) { 1928 vp = savedcbp->b_vp; 1929 bawrite(savedcbp); 1930 if ((vtype == VDIR || dopersistence) && 1931 VTOI(vp)->i_effnlink > 0) 1932 (void) ffs_syncvnode(vp, MNT_WAIT, NO_INO_UPDT); 1933 } 1934 /* 1935 * If we have been unable to allocate a block in which to do 1936 * the copy, then return non-zero so that the fragment will 1937 * not be freed. Although space will be lost, the snapshot 1938 * will stay consistent. 1939 */ 1940 if (error != 0 && wkhd != NULL) 1941 softdep_freework(wkhd); 1942 lockmgr(vp->v_vnlock, LK_RELEASE, NULL); 1943 return (error); 1944 } 1945 1946 /* 1947 * Associate snapshot files when mounting. 1948 */ 1949 void 1950 ffs_snapshot_mount(mp) 1951 struct mount *mp; 1952 { 1953 struct ufsmount *ump = VFSTOUFS(mp); 1954 struct vnode *devvp = ump->um_devvp; 1955 struct fs *fs = ump->um_fs; 1956 struct thread *td = curthread; 1957 struct snapdata *sn; 1958 struct vnode *vp; 1959 struct vnode *lastvp; 1960 struct inode *ip; 1961 struct uio auio; 1962 struct iovec aiov; 1963 void *snapblklist; 1964 char *reason; 1965 daddr_t snaplistsize; 1966 int error, snaploc, loc; 1967 1968 /* 1969 * XXX The following needs to be set before ffs_truncate or 1970 * VOP_READ can be called. 1971 */ 1972 mp->mnt_stat.f_iosize = fs->fs_bsize; 1973 /* 1974 * Process each snapshot listed in the superblock. 1975 */ 1976 vp = NULL; 1977 lastvp = NULL; 1978 sn = NULL; 1979 for (snaploc = 0; snaploc < FSMAXSNAP; snaploc++) { 1980 if (fs->fs_snapinum[snaploc] == 0) 1981 break; 1982 if ((error = ffs_vget(mp, fs->fs_snapinum[snaploc], 1983 LK_EXCLUSIVE, &vp)) != 0){ 1984 printf("ffs_snapshot_mount: vget failed %d\n", error); 1985 continue; 1986 } 1987 ip = VTOI(vp); 1988 if (!IS_SNAPSHOT(ip) || ip->i_size == 1989 lblktosize(fs, howmany(fs->fs_size, fs->fs_frag))) { 1990 if (!IS_SNAPSHOT(ip)) { 1991 reason = "non-snapshot"; 1992 } else { 1993 reason = "old format snapshot"; 1994 (void)ffs_truncate(vp, (off_t)0, 0, NOCRED); 1995 (void)ffs_syncvnode(vp, MNT_WAIT, 0); 1996 } 1997 printf("ffs_snapshot_mount: %s inode %d\n", 1998 reason, fs->fs_snapinum[snaploc]); 1999 vput(vp); 2000 vp = NULL; 2001 for (loc = snaploc + 1; loc < FSMAXSNAP; loc++) { 2002 if (fs->fs_snapinum[loc] == 0) 2003 break; 2004 fs->fs_snapinum[loc - 1] = fs->fs_snapinum[loc]; 2005 } 2006 fs->fs_snapinum[loc - 1] = 0; 2007 snaploc--; 2008 continue; 2009 } 2010 /* 2011 * Acquire a lock on the snapdata structure, creating it if 2012 * necessary. 2013 */ 2014 sn = ffs_snapdata_acquire(devvp); 2015 /* 2016 * Change vnode to use shared snapshot lock instead of the 2017 * original private lock. 2018 */ 2019 vp->v_vnlock = &sn->sn_lock; 2020 lockmgr(&vp->v_lock, LK_RELEASE, NULL); 2021 /* 2022 * Link it onto the active snapshot list. 2023 */ 2024 VI_LOCK(devvp); 2025 if (ip->i_nextsnap.tqe_prev != 0) 2026 panic("ffs_snapshot_mount: %ju already on list", 2027 (uintmax_t)ip->i_number); 2028 else 2029 TAILQ_INSERT_TAIL(&sn->sn_head, ip, i_nextsnap); 2030 vp->v_vflag |= VV_SYSTEM; 2031 VI_UNLOCK(devvp); 2032 VOP_UNLOCK(vp, 0); 2033 lastvp = vp; 2034 } 2035 vp = lastvp; 2036 /* 2037 * No usable snapshots found. 2038 */ 2039 if (sn == NULL || vp == NULL) 2040 return; 2041 /* 2042 * Allocate the space for the block hints list. We always want to 2043 * use the list from the newest snapshot. 2044 */ 2045 auio.uio_iov = &aiov; 2046 auio.uio_iovcnt = 1; 2047 aiov.iov_base = (void *)&snaplistsize; 2048 aiov.iov_len = sizeof(snaplistsize); 2049 auio.uio_resid = aiov.iov_len; 2050 auio.uio_offset = 2051 lblktosize(fs, howmany(fs->fs_size, fs->fs_frag)); 2052 auio.uio_segflg = UIO_SYSSPACE; 2053 auio.uio_rw = UIO_READ; 2054 auio.uio_td = td; 2055 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2056 if ((error = VOP_READ(vp, &auio, IO_UNIT, td->td_ucred)) != 0) { 2057 printf("ffs_snapshot_mount: read_1 failed %d\n", error); 2058 VOP_UNLOCK(vp, 0); 2059 return; 2060 } 2061 snapblklist = malloc(snaplistsize * sizeof(daddr_t), 2062 M_UFSMNT, M_WAITOK); 2063 auio.uio_iovcnt = 1; 2064 aiov.iov_base = snapblklist; 2065 aiov.iov_len = snaplistsize * sizeof (daddr_t); 2066 auio.uio_resid = aiov.iov_len; 2067 auio.uio_offset -= sizeof(snaplistsize); 2068 if ((error = VOP_READ(vp, &auio, IO_UNIT, td->td_ucred)) != 0) { 2069 printf("ffs_snapshot_mount: read_2 failed %d\n", error); 2070 VOP_UNLOCK(vp, 0); 2071 free(snapblklist, M_UFSMNT); 2072 return; 2073 } 2074 VOP_UNLOCK(vp, 0); 2075 VI_LOCK(devvp); 2076 ASSERT_VOP_LOCKED(devvp, "ffs_snapshot_mount"); 2077 sn->sn_listsize = snaplistsize; 2078 sn->sn_blklist = (daddr_t *)snapblklist; 2079 devvp->v_vflag |= VV_COPYONWRITE; 2080 VI_UNLOCK(devvp); 2081 } 2082 2083 /* 2084 * Disassociate snapshot files when unmounting. 2085 */ 2086 void 2087 ffs_snapshot_unmount(mp) 2088 struct mount *mp; 2089 { 2090 struct vnode *devvp = VFSTOUFS(mp)->um_devvp; 2091 struct snapdata *sn; 2092 struct inode *xp; 2093 struct vnode *vp; 2094 2095 VI_LOCK(devvp); 2096 sn = devvp->v_rdev->si_snapdata; 2097 while (sn != NULL && (xp = TAILQ_FIRST(&sn->sn_head)) != NULL) { 2098 vp = ITOV(xp); 2099 TAILQ_REMOVE(&sn->sn_head, xp, i_nextsnap); 2100 xp->i_nextsnap.tqe_prev = 0; 2101 lockmgr(&sn->sn_lock, LK_INTERLOCK | LK_EXCLUSIVE, 2102 VI_MTX(devvp)); 2103 lockmgr(&vp->v_lock, LK_EXCLUSIVE, NULL); 2104 KASSERT(vp->v_vnlock == &sn->sn_lock, 2105 ("ffs_snapshot_unmount: lost lock mutation")); 2106 vp->v_vnlock = &vp->v_lock; 2107 lockmgr(&vp->v_lock, LK_RELEASE, NULL); 2108 lockmgr(&sn->sn_lock, LK_RELEASE, NULL); 2109 if (xp->i_effnlink > 0) 2110 vrele(vp); 2111 VI_LOCK(devvp); 2112 sn = devvp->v_rdev->si_snapdata; 2113 } 2114 try_free_snapdata(devvp); 2115 ASSERT_VOP_LOCKED(devvp, "ffs_snapshot_unmount"); 2116 } 2117 2118 /* 2119 * Check the buffer block to be belong to device buffer that shall be 2120 * locked after snaplk. devvp shall be locked on entry, and will be 2121 * leaved locked upon exit. 2122 */ 2123 static int 2124 ffs_bp_snapblk(devvp, bp) 2125 struct vnode *devvp; 2126 struct buf *bp; 2127 { 2128 struct snapdata *sn; 2129 struct fs *fs; 2130 ufs2_daddr_t lbn, *snapblklist; 2131 int lower, upper, mid; 2132 2133 ASSERT_VI_LOCKED(devvp, "ffs_bp_snapblk"); 2134 KASSERT(devvp->v_type == VCHR, ("Not a device %p", devvp)); 2135 sn = devvp->v_rdev->si_snapdata; 2136 if (sn == NULL || TAILQ_FIRST(&sn->sn_head) == NULL) 2137 return (0); 2138 fs = TAILQ_FIRST(&sn->sn_head)->i_fs; 2139 lbn = fragstoblks(fs, dbtofsb(fs, bp->b_blkno)); 2140 snapblklist = sn->sn_blklist; 2141 upper = sn->sn_listsize - 1; 2142 lower = 1; 2143 while (lower <= upper) { 2144 mid = (lower + upper) / 2; 2145 if (snapblklist[mid] == lbn) 2146 break; 2147 if (snapblklist[mid] < lbn) 2148 lower = mid + 1; 2149 else 2150 upper = mid - 1; 2151 } 2152 if (lower <= upper) 2153 return (1); 2154 return (0); 2155 } 2156 2157 void 2158 ffs_bdflush(bo, bp) 2159 struct bufobj *bo; 2160 struct buf *bp; 2161 { 2162 struct thread *td; 2163 struct vnode *vp, *devvp; 2164 struct buf *nbp; 2165 int bp_bdskip; 2166 2167 if (bo->bo_dirty.bv_cnt <= dirtybufthresh) 2168 return; 2169 2170 td = curthread; 2171 vp = bp->b_vp; 2172 devvp = bo->__bo_vnode; 2173 KASSERT(vp == devvp, ("devvp != vp %p %p", bo, bp)); 2174 2175 VI_LOCK(devvp); 2176 bp_bdskip = ffs_bp_snapblk(devvp, bp); 2177 if (bp_bdskip) 2178 bdwriteskip++; 2179 VI_UNLOCK(devvp); 2180 if (bo->bo_dirty.bv_cnt > dirtybufthresh + 10 && !bp_bdskip) { 2181 (void) VOP_FSYNC(vp, MNT_NOWAIT, td); 2182 altbufferflushes++; 2183 } else { 2184 BO_LOCK(bo); 2185 /* 2186 * Try to find a buffer to flush. 2187 */ 2188 TAILQ_FOREACH(nbp, &bo->bo_dirty.bv_hd, b_bobufs) { 2189 if ((nbp->b_vflags & BV_BKGRDINPROG) || 2190 BUF_LOCK(nbp, 2191 LK_EXCLUSIVE | LK_NOWAIT, NULL)) 2192 continue; 2193 if (bp == nbp) 2194 panic("bdwrite: found ourselves"); 2195 BO_UNLOCK(bo); 2196 /* 2197 * Don't countdeps with the bo lock 2198 * held. 2199 */ 2200 if (buf_countdeps(nbp, 0)) { 2201 BO_LOCK(bo); 2202 BUF_UNLOCK(nbp); 2203 continue; 2204 } 2205 if (bp_bdskip) { 2206 VI_LOCK(devvp); 2207 if (!ffs_bp_snapblk(vp, nbp)) { 2208 VI_UNLOCK(devvp); 2209 BO_LOCK(bo); 2210 BUF_UNLOCK(nbp); 2211 continue; 2212 } 2213 VI_UNLOCK(devvp); 2214 } 2215 if (nbp->b_flags & B_CLUSTEROK) { 2216 vfs_bio_awrite(nbp); 2217 } else { 2218 bremfree(nbp); 2219 bawrite(nbp); 2220 } 2221 dirtybufferflushes++; 2222 break; 2223 } 2224 if (nbp == NULL) 2225 BO_UNLOCK(bo); 2226 } 2227 } 2228 2229 /* 2230 * Check for need to copy block that is about to be written, 2231 * copying the block if necessary. 2232 */ 2233 int 2234 ffs_copyonwrite(devvp, bp) 2235 struct vnode *devvp; 2236 struct buf *bp; 2237 { 2238 struct snapdata *sn; 2239 struct buf *ibp, *cbp, *savedcbp = NULL; 2240 struct thread *td = curthread; 2241 struct fs *fs; 2242 struct inode *ip; 2243 struct vnode *vp = NULL; 2244 ufs2_daddr_t lbn, blkno, *snapblklist; 2245 int lower, upper, mid, indiroff, error = 0; 2246 int launched_async_io, prev_norunningbuf; 2247 long saved_runningbufspace; 2248 2249 if (devvp != bp->b_vp && IS_SNAPSHOT(VTOI(bp->b_vp))) 2250 return (0); /* Update on a snapshot file */ 2251 if (td->td_pflags & TDP_COWINPROGRESS) 2252 panic("ffs_copyonwrite: recursive call"); 2253 /* 2254 * First check to see if it is in the preallocated list. 2255 * By doing this check we avoid several potential deadlocks. 2256 */ 2257 VI_LOCK(devvp); 2258 sn = devvp->v_rdev->si_snapdata; 2259 if (sn == NULL || 2260 TAILQ_EMPTY(&sn->sn_head)) { 2261 VI_UNLOCK(devvp); 2262 return (0); /* No snapshot */ 2263 } 2264 ip = TAILQ_FIRST(&sn->sn_head); 2265 fs = ip->i_fs; 2266 lbn = fragstoblks(fs, dbtofsb(fs, bp->b_blkno)); 2267 snapblklist = sn->sn_blklist; 2268 upper = sn->sn_listsize - 1; 2269 lower = 1; 2270 while (lower <= upper) { 2271 mid = (lower + upper) / 2; 2272 if (snapblklist[mid] == lbn) 2273 break; 2274 if (snapblklist[mid] < lbn) 2275 lower = mid + 1; 2276 else 2277 upper = mid - 1; 2278 } 2279 if (lower <= upper) { 2280 VI_UNLOCK(devvp); 2281 return (0); 2282 } 2283 launched_async_io = 0; 2284 prev_norunningbuf = td->td_pflags & TDP_NORUNNINGBUF; 2285 /* 2286 * Since I/O on bp isn't yet in progress and it may be blocked 2287 * for a long time waiting on snaplk, back it out of 2288 * runningbufspace, possibly waking other threads waiting for space. 2289 */ 2290 saved_runningbufspace = bp->b_runningbufspace; 2291 if (saved_runningbufspace != 0) 2292 runningbufwakeup(bp); 2293 /* 2294 * Not in the precomputed list, so check the snapshots. 2295 */ 2296 while (lockmgr(&sn->sn_lock, LK_INTERLOCK | LK_EXCLUSIVE | LK_SLEEPFAIL, 2297 VI_MTX(devvp)) != 0) { 2298 VI_LOCK(devvp); 2299 sn = devvp->v_rdev->si_snapdata; 2300 if (sn == NULL || 2301 TAILQ_EMPTY(&sn->sn_head)) { 2302 VI_UNLOCK(devvp); 2303 if (saved_runningbufspace != 0) { 2304 bp->b_runningbufspace = saved_runningbufspace; 2305 atomic_add_long(&runningbufspace, 2306 bp->b_runningbufspace); 2307 } 2308 return (0); /* Snapshot gone */ 2309 } 2310 } 2311 TAILQ_FOREACH(ip, &sn->sn_head, i_nextsnap) { 2312 vp = ITOV(ip); 2313 if (DOINGSOFTDEP(vp)) 2314 softdep_prealloc(vp, MNT_WAIT); 2315 /* 2316 * We ensure that everything of our own that needs to be 2317 * copied will be done at the time that ffs_snapshot is 2318 * called. Thus we can skip the check here which can 2319 * deadlock in doing the lookup in UFS_BALLOC. 2320 */ 2321 if (bp->b_vp == vp) 2322 continue; 2323 /* 2324 * Check to see if block needs to be copied. We do not have 2325 * to hold the snapshot lock while doing this lookup as it 2326 * will never require any additional allocations for the 2327 * snapshot inode. 2328 */ 2329 if (lbn < NDADDR) { 2330 blkno = DIP(ip, i_db[lbn]); 2331 } else { 2332 td->td_pflags |= TDP_COWINPROGRESS | TDP_NORUNNINGBUF; 2333 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)lbn), 2334 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp); 2335 td->td_pflags &= ~TDP_COWINPROGRESS; 2336 if (error) 2337 break; 2338 indiroff = (lbn - NDADDR) % NINDIR(fs); 2339 if (ip->i_ump->um_fstype == UFS1) 2340 blkno=((ufs1_daddr_t *)(ibp->b_data))[indiroff]; 2341 else 2342 blkno=((ufs2_daddr_t *)(ibp->b_data))[indiroff]; 2343 bqrelse(ibp); 2344 } 2345 #ifdef INVARIANTS 2346 if (blkno == BLK_SNAP && bp->b_lblkno >= 0) 2347 panic("ffs_copyonwrite: bad copy block"); 2348 #endif 2349 if (blkno != 0) 2350 continue; 2351 /* 2352 * Allocate the block into which to do the copy. Since 2353 * multiple processes may all try to copy the same block, 2354 * we have to recheck our need to do a copy if we sleep 2355 * waiting for the lock. 2356 * 2357 * Because all snapshots on a filesystem share a single 2358 * lock, we ensure that we will never be in competition 2359 * with another process to allocate a block. 2360 */ 2361 td->td_pflags |= TDP_COWINPROGRESS | TDP_NORUNNINGBUF; 2362 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)lbn), 2363 fs->fs_bsize, KERNCRED, 0, &cbp); 2364 td->td_pflags &= ~TDP_COWINPROGRESS; 2365 if (error) 2366 break; 2367 #ifdef DEBUG 2368 if (snapdebug) { 2369 printf("Copyonwrite: snapino %ju lbn %jd for ", 2370 (uintmax_t)ip->i_number, (intmax_t)lbn); 2371 if (bp->b_vp == devvp) 2372 printf("fs metadata"); 2373 else 2374 printf("inum %ju", 2375 (uintmax_t)VTOI(bp->b_vp)->i_number); 2376 printf(" lblkno %jd to blkno %jd\n", 2377 (intmax_t)bp->b_lblkno, (intmax_t)cbp->b_blkno); 2378 } 2379 #endif 2380 /* 2381 * If we have already read the old block contents, then 2382 * simply copy them to the new block. Note that we need 2383 * to synchronously write snapshots that have not been 2384 * unlinked, and hence will be visible after a crash, 2385 * to ensure their integrity. At a minimum we ensure the 2386 * integrity of the filesystem metadata, but use the 2387 * dopersistence sysctl-setable flag to decide on the 2388 * persistence needed for file content data. 2389 */ 2390 if (savedcbp != 0) { 2391 bcopy(savedcbp->b_data, cbp->b_data, fs->fs_bsize); 2392 bawrite(cbp); 2393 if ((devvp == bp->b_vp || bp->b_vp->v_type == VDIR || 2394 dopersistence) && ip->i_effnlink > 0) 2395 (void) ffs_syncvnode(vp, MNT_WAIT, NO_INO_UPDT); 2396 else 2397 launched_async_io = 1; 2398 continue; 2399 } 2400 /* 2401 * Otherwise, read the old block contents into the buffer. 2402 */ 2403 if ((error = readblock(vp, cbp, lbn)) != 0) { 2404 bzero(cbp->b_data, fs->fs_bsize); 2405 bawrite(cbp); 2406 if ((devvp == bp->b_vp || bp->b_vp->v_type == VDIR || 2407 dopersistence) && ip->i_effnlink > 0) 2408 (void) ffs_syncvnode(vp, MNT_WAIT, NO_INO_UPDT); 2409 else 2410 launched_async_io = 1; 2411 break; 2412 } 2413 savedcbp = cbp; 2414 } 2415 /* 2416 * Note that we need to synchronously write snapshots that 2417 * have not been unlinked, and hence will be visible after 2418 * a crash, to ensure their integrity. At a minimum we 2419 * ensure the integrity of the filesystem metadata, but 2420 * use the dopersistence sysctl-setable flag to decide on 2421 * the persistence needed for file content data. 2422 */ 2423 if (savedcbp) { 2424 vp = savedcbp->b_vp; 2425 bawrite(savedcbp); 2426 if ((devvp == bp->b_vp || bp->b_vp->v_type == VDIR || 2427 dopersistence) && VTOI(vp)->i_effnlink > 0) 2428 (void) ffs_syncvnode(vp, MNT_WAIT, NO_INO_UPDT); 2429 else 2430 launched_async_io = 1; 2431 } 2432 lockmgr(vp->v_vnlock, LK_RELEASE, NULL); 2433 td->td_pflags = (td->td_pflags & ~TDP_NORUNNINGBUF) | 2434 prev_norunningbuf; 2435 if (launched_async_io && (td->td_pflags & TDP_NORUNNINGBUF) == 0) 2436 waitrunningbufspace(); 2437 /* 2438 * I/O on bp will now be started, so count it in runningbufspace. 2439 */ 2440 if (saved_runningbufspace != 0) { 2441 bp->b_runningbufspace = saved_runningbufspace; 2442 atomic_add_long(&runningbufspace, bp->b_runningbufspace); 2443 } 2444 return (error); 2445 } 2446 2447 /* 2448 * sync snapshots to force freework records waiting on snapshots to claim 2449 * blocks to free. 2450 */ 2451 void 2452 ffs_sync_snap(mp, waitfor) 2453 struct mount *mp; 2454 int waitfor; 2455 { 2456 struct snapdata *sn; 2457 struct vnode *devvp; 2458 struct vnode *vp; 2459 struct inode *ip; 2460 2461 devvp = VFSTOUFS(mp)->um_devvp; 2462 if ((devvp->v_vflag & VV_COPYONWRITE) == 0) 2463 return; 2464 for (;;) { 2465 VI_LOCK(devvp); 2466 sn = devvp->v_rdev->si_snapdata; 2467 if (sn == NULL) { 2468 VI_UNLOCK(devvp); 2469 return; 2470 } 2471 if (lockmgr(&sn->sn_lock, 2472 LK_INTERLOCK | LK_EXCLUSIVE | LK_SLEEPFAIL, 2473 VI_MTX(devvp)) == 0) 2474 break; 2475 } 2476 TAILQ_FOREACH(ip, &sn->sn_head, i_nextsnap) { 2477 vp = ITOV(ip); 2478 ffs_syncvnode(vp, waitfor, NO_INO_UPDT); 2479 } 2480 lockmgr(&sn->sn_lock, LK_RELEASE, NULL); 2481 } 2482 2483 /* 2484 * Read the specified block into the given buffer. 2485 * Much of this boiler-plate comes from bwrite(). 2486 */ 2487 static int 2488 readblock(vp, bp, lbn) 2489 struct vnode *vp; 2490 struct buf *bp; 2491 ufs2_daddr_t lbn; 2492 { 2493 struct inode *ip = VTOI(vp); 2494 struct bio *bip; 2495 2496 bip = g_alloc_bio(); 2497 bip->bio_cmd = BIO_READ; 2498 bip->bio_offset = dbtob(fsbtodb(ip->i_fs, blkstofrags(ip->i_fs, lbn))); 2499 bip->bio_data = bp->b_data; 2500 bip->bio_length = bp->b_bcount; 2501 bip->bio_done = NULL; 2502 2503 g_io_request(bip, ip->i_devvp->v_bufobj.bo_private); 2504 bp->b_error = biowait(bip, "snaprdb"); 2505 g_destroy_bio(bip); 2506 return (bp->b_error); 2507 } 2508 2509 #endif 2510 2511 /* 2512 * Process file deletes that were deferred by ufs_inactive() due to 2513 * the file system being suspended. Transfer IN_LAZYACCESS into 2514 * IN_MODIFIED for vnodes that were accessed during suspension. 2515 */ 2516 void 2517 process_deferred_inactive(struct mount *mp) 2518 { 2519 struct vnode *vp, *mvp; 2520 struct inode *ip; 2521 struct thread *td; 2522 int error; 2523 2524 td = curthread; 2525 (void) vn_start_secondary_write(NULL, &mp, V_WAIT); 2526 loop: 2527 MNT_VNODE_FOREACH_ALL(vp, mp, mvp) { 2528 /* 2529 * IN_LAZYACCESS is checked here without holding any 2530 * vnode lock, but this flag is set only while holding 2531 * vnode interlock. 2532 */ 2533 if (vp->v_type == VNON || 2534 ((VTOI(vp)->i_flag & IN_LAZYACCESS) == 0 && 2535 ((vp->v_iflag & VI_OWEINACT) == 0 || vp->v_usecount > 0))) { 2536 VI_UNLOCK(vp); 2537 continue; 2538 } 2539 vholdl(vp); 2540 error = vn_lock(vp, LK_EXCLUSIVE | LK_INTERLOCK); 2541 if (error != 0) { 2542 vdrop(vp); 2543 if (error == ENOENT) 2544 continue; /* vnode recycled */ 2545 MNT_VNODE_FOREACH_ALL_ABORT(mp, mvp); 2546 goto loop; 2547 } 2548 ip = VTOI(vp); 2549 if ((ip->i_flag & IN_LAZYACCESS) != 0) { 2550 ip->i_flag &= ~IN_LAZYACCESS; 2551 ip->i_flag |= IN_MODIFIED; 2552 } 2553 VI_LOCK(vp); 2554 if ((vp->v_iflag & VI_OWEINACT) == 0 || vp->v_usecount > 0) { 2555 VI_UNLOCK(vp); 2556 VOP_UNLOCK(vp, 0); 2557 vdrop(vp); 2558 continue; 2559 } 2560 vinactive(vp, td); 2561 VNASSERT((vp->v_iflag & VI_OWEINACT) == 0, vp, 2562 ("process_deferred_inactive: got VI_OWEINACT")); 2563 VI_UNLOCK(vp); 2564 VOP_UNLOCK(vp, 0); 2565 vdrop(vp); 2566 } 2567 vn_finished_secondary_write(mp); 2568 } 2569 2570 #ifndef NO_FFS_SNAPSHOT 2571 2572 static struct snapdata * 2573 ffs_snapdata_alloc(void) 2574 { 2575 struct snapdata *sn; 2576 2577 /* 2578 * Fetch a snapdata from the free list if there is one available. 2579 */ 2580 mtx_lock(&snapfree_lock); 2581 sn = LIST_FIRST(&snapfree); 2582 if (sn != NULL) 2583 LIST_REMOVE(sn, sn_link); 2584 mtx_unlock(&snapfree_lock); 2585 if (sn != NULL) 2586 return (sn); 2587 /* 2588 * If there were no free snapdatas allocate one. 2589 */ 2590 sn = malloc(sizeof *sn, M_UFSMNT, M_WAITOK | M_ZERO); 2591 TAILQ_INIT(&sn->sn_head); 2592 lockinit(&sn->sn_lock, PVFS, "snaplk", VLKTIMEOUT, 2593 LK_CANRECURSE | LK_NOSHARE); 2594 return (sn); 2595 } 2596 2597 /* 2598 * The snapdata is never freed because we can not be certain that 2599 * there are no threads sleeping on the snap lock. Persisting 2600 * them permanently avoids costly synchronization in ffs_lock(). 2601 */ 2602 static void 2603 ffs_snapdata_free(struct snapdata *sn) 2604 { 2605 mtx_lock(&snapfree_lock); 2606 LIST_INSERT_HEAD(&snapfree, sn, sn_link); 2607 mtx_unlock(&snapfree_lock); 2608 } 2609 2610 /* Try to free snapdata associated with devvp */ 2611 static void 2612 try_free_snapdata(struct vnode *devvp) 2613 { 2614 struct snapdata *sn; 2615 ufs2_daddr_t *snapblklist; 2616 2617 ASSERT_VI_LOCKED(devvp, "try_free_snapdata"); 2618 sn = devvp->v_rdev->si_snapdata; 2619 2620 if (sn == NULL || TAILQ_FIRST(&sn->sn_head) != NULL || 2621 (devvp->v_vflag & VV_COPYONWRITE) == 0) { 2622 VI_UNLOCK(devvp); 2623 return; 2624 } 2625 2626 devvp->v_rdev->si_snapdata = NULL; 2627 devvp->v_vflag &= ~VV_COPYONWRITE; 2628 lockmgr(&sn->sn_lock, LK_DRAIN|LK_INTERLOCK, VI_MTX(devvp)); 2629 snapblklist = sn->sn_blklist; 2630 sn->sn_blklist = NULL; 2631 sn->sn_listsize = 0; 2632 lockmgr(&sn->sn_lock, LK_RELEASE, NULL); 2633 if (snapblklist != NULL) 2634 free(snapblklist, M_UFSMNT); 2635 ffs_snapdata_free(sn); 2636 } 2637 2638 static struct snapdata * 2639 ffs_snapdata_acquire(struct vnode *devvp) 2640 { 2641 struct snapdata *nsn; 2642 struct snapdata *sn; 2643 2644 /* 2645 * Allocate a free snapdata. This is done before acquiring the 2646 * devvp lock to avoid allocation while the devvp interlock is 2647 * held. 2648 */ 2649 nsn = ffs_snapdata_alloc(); 2650 /* 2651 * If there snapshots already exist on this filesystem grab a 2652 * reference to the shared lock. Otherwise this is the first 2653 * snapshot on this filesystem and we need to use our 2654 * pre-allocated snapdata. 2655 */ 2656 VI_LOCK(devvp); 2657 if (devvp->v_rdev->si_snapdata == NULL) { 2658 devvp->v_rdev->si_snapdata = nsn; 2659 nsn = NULL; 2660 } 2661 sn = devvp->v_rdev->si_snapdata; 2662 /* 2663 * Acquire the snapshot lock. 2664 */ 2665 lockmgr(&sn->sn_lock, 2666 LK_INTERLOCK | LK_EXCLUSIVE | LK_RETRY, VI_MTX(devvp)); 2667 /* 2668 * Free any unused snapdata. 2669 */ 2670 if (nsn != NULL) 2671 ffs_snapdata_free(nsn); 2672 2673 return (sn); 2674 } 2675 2676 #endif
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