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