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 * $FreeBSD$ 35 */ 36 37 #include <sys/param.h> 38 #include <sys/stdint.h> 39 #include <sys/kernel.h> 40 #include <sys/systm.h> 41 #include <sys/conf.h> 42 #include <sys/bio.h> 43 #include <sys/buf.h> 44 #include <sys/proc.h> 45 #include <sys/namei.h> 46 #include <sys/stat.h> 47 #include <sys/malloc.h> 48 #include <sys/mount.h> 49 #include <sys/resource.h> 50 #include <sys/resourcevar.h> 51 #include <sys/vnode.h> 52 53 #include <ufs/ufs/extattr.h> 54 #include <ufs/ufs/quota.h> 55 #include <ufs/ufs/ufsmount.h> 56 #include <ufs/ufs/inode.h> 57 #include <ufs/ufs/ufs_extern.h> 58 59 #include <ufs/ffs/fs.h> 60 #include <ufs/ffs/ffs_extern.h> 61 62 #define KERNCRED thread0.td_ucred 63 #define DEBUG 1 64 65 static int cgaccount(int, struct vnode *, struct buf *, int); 66 static int expunge_ufs1(struct vnode *, struct inode *, struct fs *, 67 int (*)(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *, struct fs *, 68 ufs_lbn_t, int), int); 69 static int indiracct_ufs1(struct vnode *, struct vnode *, int, 70 ufs1_daddr_t, ufs_lbn_t, ufs_lbn_t, ufs_lbn_t, ufs_lbn_t, struct fs *, 71 int (*)(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *, struct fs *, 72 ufs_lbn_t, int), int); 73 static int fullacct_ufs1(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *, 74 struct fs *, ufs_lbn_t, int); 75 static int snapacct_ufs1(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *, 76 struct fs *, ufs_lbn_t, int); 77 static int mapacct_ufs1(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *, 78 struct fs *, ufs_lbn_t, int); 79 static int expunge_ufs2(struct vnode *, struct inode *, struct fs *, 80 int (*)(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *, struct fs *, 81 ufs_lbn_t, int), int); 82 static int indiracct_ufs2(struct vnode *, struct vnode *, int, 83 ufs2_daddr_t, ufs_lbn_t, ufs_lbn_t, ufs_lbn_t, ufs_lbn_t, struct fs *, 84 int (*)(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *, struct fs *, 85 ufs_lbn_t, int), int); 86 static int fullacct_ufs2(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *, 87 struct fs *, ufs_lbn_t, int); 88 static int snapacct_ufs2(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *, 89 struct fs *, ufs_lbn_t, int); 90 static int mapacct_ufs2(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *, 91 struct fs *, ufs_lbn_t, int); 92 static int ffs_copyonwrite(struct vnode *, struct buf *); 93 static int readblock(struct buf *, ufs2_daddr_t); 94 95 /* 96 * To ensure the consistency of snapshots across crashes, we must 97 * synchronously write out copied blocks before allowing the 98 * originals to be modified. Because of the rather severe speed 99 * penalty that this imposes, the following flag allows this 100 * crash persistence to be disabled. 101 */ 102 int dopersistence = 0; 103 104 #ifdef DEBUG 105 #include <sys/sysctl.h> 106 SYSCTL_INT(_debug, OID_AUTO, dopersistence, CTLFLAG_RW, &dopersistence, 0, ""); 107 int snapdebug = 0; 108 SYSCTL_INT(_debug, OID_AUTO, snapdebug, CTLFLAG_RW, &snapdebug, 0, ""); 109 int collectsnapstats = 0; 110 SYSCTL_INT(_debug, OID_AUTO, collectsnapstats, CTLFLAG_RW, &collectsnapstats, 111 0, ""); 112 #endif /* DEBUG */ 113 114 /* 115 * Create a snapshot file and initialize it for the filesystem. 116 */ 117 int 118 ffs_snapshot(mp, snapfile) 119 struct mount *mp; 120 char *snapfile; 121 { 122 ufs2_daddr_t numblks, blkno; 123 int error, cg, snaploc; 124 int i, size, len, loc; 125 int flag = mp->mnt_flag; 126 struct timespec starttime = {0, 0}, endtime; 127 char saved_nice = 0; 128 long redo = 0, snaplistsize; 129 int32_t *lp; 130 void *space; 131 daddr_t *snapblklist; 132 struct fs *copy_fs = NULL, *fs = VFSTOUFS(mp)->um_fs; 133 struct snaphead *snaphead; 134 struct thread *td = curthread; 135 struct inode *ip, *xp; 136 struct buf *bp, *nbp, *ibp, *sbp = NULL; 137 struct nameidata nd; 138 struct mount *wrtmp; 139 struct vattr vat; 140 struct vnode *vp, *xvp, *nvp, *devvp; 141 struct uio auio; 142 struct iovec aiov; 143 144 /* 145 * Need to serialize access to snapshot code per filesystem. 146 */ 147 /* 148 * Assign a snapshot slot in the superblock. 149 */ 150 for (snaploc = 0; snaploc < FSMAXSNAP; snaploc++) 151 if (fs->fs_snapinum[snaploc] == 0) 152 break; 153 if (snaploc == FSMAXSNAP) 154 return (ENOSPC); 155 /* 156 * Create the snapshot file. 157 */ 158 restart: 159 NDINIT(&nd, CREATE, LOCKPARENT | LOCKLEAF, UIO_USERSPACE, snapfile, td); 160 if ((error = namei(&nd)) != 0) 161 return (error); 162 if (nd.ni_vp != NULL) { 163 vput(nd.ni_vp); 164 error = EEXIST; 165 } 166 if (nd.ni_dvp->v_mount != mp) 167 error = EXDEV; 168 if (error) { 169 NDFREE(&nd, NDF_ONLY_PNBUF); 170 if (nd.ni_dvp == nd.ni_vp) 171 vrele(nd.ni_dvp); 172 else 173 vput(nd.ni_dvp); 174 return (error); 175 } 176 VATTR_NULL(&vat); 177 vat.va_type = VREG; 178 vat.va_mode = S_IRUSR; 179 vat.va_vaflags |= VA_EXCLUSIVE; 180 if (VOP_GETWRITEMOUNT(nd.ni_dvp, &wrtmp)) 181 wrtmp = NULL; 182 if (wrtmp != mp) 183 panic("ffs_snapshot: mount mismatch"); 184 if (vn_start_write(NULL, &wrtmp, V_NOWAIT) != 0) { 185 NDFREE(&nd, NDF_ONLY_PNBUF); 186 vput(nd.ni_dvp); 187 if ((error = vn_start_write(NULL, &wrtmp, 188 V_XSLEEP | PCATCH)) != 0) 189 return (error); 190 goto restart; 191 } 192 VOP_LEASE(nd.ni_dvp, td, KERNCRED, LEASE_WRITE); 193 error = VOP_CREATE(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vat); 194 vput(nd.ni_dvp); 195 if (error) { 196 NDFREE(&nd, NDF_ONLY_PNBUF); 197 vn_finished_write(wrtmp); 198 return (error); 199 } 200 vp = nd.ni_vp; 201 ip = VTOI(vp); 202 devvp = ip->i_devvp; 203 /* 204 * Allocate and copy the last block contents so as to be able 205 * to set size to that of the filesystem. 206 */ 207 numblks = howmany(fs->fs_size, fs->fs_frag); 208 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)(numblks - 1)), 209 fs->fs_bsize, KERNCRED, BA_CLRBUF, &bp); 210 if (error) 211 goto out; 212 ip->i_size = lblktosize(fs, (off_t)numblks); 213 DIP(ip, i_size) = ip->i_size; 214 ip->i_flag |= IN_CHANGE | IN_UPDATE; 215 if ((error = readblock(bp, numblks - 1)) != 0) 216 goto out; 217 bawrite(bp); 218 /* 219 * Preallocate critical data structures so that we can copy 220 * them in without further allocation after we suspend all 221 * operations on the filesystem. We would like to just release 222 * the allocated buffers without writing them since they will 223 * be filled in below once we are ready to go, but this upsets 224 * the soft update code, so we go ahead and write the new buffers. 225 * 226 * Allocate all indirect blocks and mark all of them as not 227 * needing to be copied. 228 */ 229 for (blkno = NDADDR; blkno < numblks; blkno += NINDIR(fs)) { 230 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)blkno), 231 fs->fs_bsize, td->td_ucred, BA_METAONLY, &ibp); 232 if (error) 233 goto out; 234 bawrite(ibp); 235 } 236 /* 237 * Allocate copies for the superblock and its summary information. 238 */ 239 error = UFS_BALLOC(vp, fs->fs_sblockloc, fs->fs_sbsize, KERNCRED, 240 0, &nbp); 241 if (error) 242 goto out; 243 bawrite(nbp); 244 blkno = fragstoblks(fs, fs->fs_csaddr); 245 len = howmany(fs->fs_cssize, fs->fs_bsize); 246 for (loc = 0; loc < len; loc++) { 247 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)(blkno + loc)), 248 fs->fs_bsize, KERNCRED, 0, &nbp); 249 if (error) 250 goto out; 251 bawrite(nbp); 252 } 253 /* 254 * Allocate all cylinder group blocks. 255 */ 256 for (cg = 0; cg < fs->fs_ncg; cg++) { 257 error = UFS_BALLOC(vp, (off_t)(cgtod(fs, cg)) << fs->fs_fshift, 258 fs->fs_bsize, KERNCRED, 0, &nbp); 259 if (error) 260 goto out; 261 bawrite(nbp); 262 } 263 /* 264 * Copy all the cylinder group maps. Although the 265 * filesystem is still active, we hope that only a few 266 * cylinder groups will change between now and when we 267 * suspend operations. Thus, we will be able to quickly 268 * touch up the few cylinder groups that changed during 269 * the suspension period. 270 */ 271 len = howmany(fs->fs_ncg, NBBY); 272 MALLOC(fs->fs_active, int *, len, M_DEVBUF, 0); 273 bzero(fs->fs_active, len); 274 for (cg = 0; cg < fs->fs_ncg; cg++) { 275 error = UFS_BALLOC(vp, (off_t)(cgtod(fs, cg)) << fs->fs_fshift, 276 fs->fs_bsize, KERNCRED, 0, &nbp); 277 if (error) 278 goto out; 279 error = cgaccount(cg, vp, nbp, 1); 280 bawrite(nbp); 281 if (error) 282 goto out; 283 } 284 /* 285 * Change inode to snapshot type file. 286 */ 287 ip->i_flags |= SF_SNAPSHOT; 288 DIP(ip, i_flags) = ip->i_flags; 289 ip->i_flag |= IN_CHANGE | IN_UPDATE; 290 /* 291 * Ensure that the snapshot is completely on disk. 292 * Since we have marked it as a snapshot it is safe to 293 * unlock it as no process will be allowed to write to it. 294 */ 295 if ((error = VOP_FSYNC(vp, KERNCRED, MNT_WAIT, td)) != 0) 296 goto out; 297 VOP_UNLOCK(vp, 0, td); 298 /* 299 * All allocations are done, so we can now snapshot the system. 300 * 301 * Recind nice scheduling while running with the filesystem suspended. 302 */ 303 if (td->td_ksegrp->kg_nice > 0) { 304 saved_nice = td->td_ksegrp->kg_nice; 305 td->td_ksegrp->kg_nice = 0; 306 } 307 /* 308 * Suspend operation on filesystem. 309 */ 310 for (;;) { 311 vn_finished_write(wrtmp); 312 if ((error = vfs_write_suspend(vp->v_mount)) != 0) { 313 vn_start_write(NULL, &wrtmp, V_WAIT); 314 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); 315 goto out; 316 } 317 if (mp->mnt_kern_flag & MNTK_SUSPENDED) 318 break; 319 vn_start_write(NULL, &wrtmp, V_WAIT); 320 } 321 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); 322 if (collectsnapstats) 323 nanotime(&starttime); 324 /* 325 * First, copy all the cylinder group maps that have changed. 326 */ 327 for (cg = 0; cg < fs->fs_ncg; cg++) { 328 if ((ACTIVECGNUM(fs, cg) & ACTIVECGOFF(cg)) != 0) 329 continue; 330 redo++; 331 error = UFS_BALLOC(vp, (off_t)(cgtod(fs, cg)) << fs->fs_fshift, 332 fs->fs_bsize, KERNCRED, 0, &nbp); 333 if (error) 334 goto out1; 335 error = cgaccount(cg, vp, nbp, 2); 336 bawrite(nbp); 337 if (error) 338 goto out1; 339 } 340 /* 341 * Grab a copy of the superblock and its summary information. 342 * We delay writing it until the suspension is released below. 343 */ 344 error = bread(vp, lblkno(fs, fs->fs_sblockloc), fs->fs_bsize, 345 KERNCRED, &sbp); 346 if (error) { 347 brelse(sbp); 348 sbp = NULL; 349 goto out1; 350 } 351 loc = blkoff(fs, fs->fs_sblockloc); 352 copy_fs = (struct fs *)(sbp->b_data + loc); 353 bcopy(fs, copy_fs, fs->fs_sbsize); 354 if ((fs->fs_flags & (FS_UNCLEAN | FS_NEEDSFSCK)) == 0) 355 copy_fs->fs_clean = 1; 356 if (fs->fs_sbsize < SBLOCKSIZE) 357 bzero(&sbp->b_data[loc + fs->fs_sbsize], 358 SBLOCKSIZE - fs->fs_sbsize); 359 size = blkroundup(fs, fs->fs_cssize); 360 if (fs->fs_contigsumsize > 0) 361 size += fs->fs_ncg * sizeof(int32_t); 362 space = malloc((u_long)size, M_UFSMNT, 0); 363 copy_fs->fs_csp = space; 364 bcopy(fs->fs_csp, copy_fs->fs_csp, fs->fs_cssize); 365 (char *)space += fs->fs_cssize; 366 loc = howmany(fs->fs_cssize, fs->fs_fsize); 367 i = fs->fs_frag - loc % fs->fs_frag; 368 len = (i == fs->fs_frag) ? 0 : i * fs->fs_fsize; 369 if (len > 0) { 370 if ((error = bread(devvp, fsbtodb(fs, fs->fs_csaddr + loc), 371 len, KERNCRED, &bp)) != 0) { 372 brelse(bp); 373 free(copy_fs->fs_csp, M_UFSMNT); 374 bawrite(sbp); 375 sbp = NULL; 376 goto out1; 377 } 378 bcopy(bp->b_data, space, (u_int)len); 379 (char *)space += len; 380 bp->b_flags |= B_INVAL | B_NOCACHE; 381 brelse(bp); 382 } 383 if (fs->fs_contigsumsize > 0) { 384 copy_fs->fs_maxcluster = lp = space; 385 for (i = 0; i < fs->fs_ncg; i++) 386 *lp++ = fs->fs_contigsumsize; 387 } 388 /* 389 * We must check for active files that have been unlinked 390 * (e.g., with a zero link count). We have to expunge all 391 * trace of these files from the snapshot so that they are 392 * not reclaimed prematurely by fsck or unnecessarily dumped. 393 * We turn off the MNTK_SUSPENDED flag to avoid a panic from 394 * spec_strategy about writing on a suspended filesystem. 395 * Note that we skip unlinked snapshot files as they will 396 * be handled separately below. 397 */ 398 mp->mnt_kern_flag &= ~MNTK_SUSPENDED; 399 mtx_lock(&mntvnode_mtx); 400 loop: 401 for (xvp = TAILQ_FIRST(&mp->mnt_nvnodelist); xvp; xvp = nvp) { 402 /* 403 * Make sure this vnode wasn't reclaimed in getnewvnode(). 404 * Start over if it has (it won't be on the list anymore). 405 */ 406 if (xvp->v_mount != mp) 407 goto loop; 408 nvp = TAILQ_NEXT(xvp, v_nmntvnodes); 409 mtx_unlock(&mntvnode_mtx); 410 mp_fixme("Unlocked GETATTR."); 411 if (vrefcnt(xvp) == 0 || xvp->v_type == VNON || 412 (VTOI(xvp)->i_flags & SF_SNAPSHOT) || 413 (VOP_GETATTR(xvp, &vat, td->td_proc->p_ucred, td) == 0 && 414 vat.va_nlink > 0)) { 415 mtx_lock(&mntvnode_mtx); 416 continue; 417 } 418 if (snapdebug) 419 vprint("ffs_snapshot: busy vnode", xvp); 420 if (vn_lock(xvp, LK_EXCLUSIVE, td) != 0) 421 goto loop; 422 xp = VTOI(xvp); 423 /* 424 * If there is a fragment, clear it here. 425 */ 426 blkno = 0; 427 loc = howmany(xp->i_size, fs->fs_bsize) - 1; 428 if (loc < NDADDR) { 429 len = fragroundup(fs, blkoff(fs, xp->i_size)); 430 if (len < fs->fs_bsize) { 431 ffs_blkfree(copy_fs, vp, DIP(xp, i_db[loc]), 432 len, xp->i_number); 433 blkno = DIP(xp, i_db[loc]); 434 DIP(xp, i_db[loc]) = 0; 435 } 436 } 437 if (xp->i_ump->um_fstype == UFS1) 438 error = expunge_ufs1(vp, xp, copy_fs, fullacct_ufs1, 439 BLK_NOCOPY); 440 else 441 error = expunge_ufs2(vp, xp, copy_fs, fullacct_ufs2, 442 BLK_NOCOPY); 443 if (blkno) 444 DIP(xp, i_db[loc]) = blkno; 445 if (!error) 446 error = ffs_freefile(copy_fs, vp, xp->i_number, 447 xp->i_mode); 448 VOP_UNLOCK(xvp, 0, td); 449 if (error) { 450 free(copy_fs->fs_csp, M_UFSMNT); 451 bawrite(sbp); 452 sbp = NULL; 453 goto out1; 454 } 455 mtx_lock(&mntvnode_mtx); 456 } 457 mtx_unlock(&mntvnode_mtx); 458 /* 459 * If there already exist snapshots on this filesystem, grab a 460 * reference to their shared lock. If this is the first snapshot 461 * on this filesystem, we need to allocate a lock for the snapshots 462 * to share. In either case, acquire the snapshot lock and give 463 * up our original private lock. 464 */ 465 VI_LOCK(devvp); 466 snaphead = &devvp->v_rdev->si_snapshots; 467 if ((xp = TAILQ_FIRST(snaphead)) != NULL) { 468 VI_LOCK(vp); 469 vp->v_vnlock = ITOV(xp)->v_vnlock; 470 VI_UNLOCK(devvp); 471 } else { 472 struct lock *lkp; 473 474 VI_UNLOCK(devvp); 475 MALLOC(lkp, struct lock *, sizeof(struct lock), M_UFSMNT, 476 0); 477 lockinit(lkp, PVFS, "snaplk", VLKTIMEOUT, 478 LK_CANRECURSE | LK_NOPAUSE); 479 VI_LOCK(vp); 480 vp->v_vnlock = lkp; 481 } 482 vn_lock(vp, LK_INTERLOCK | LK_EXCLUSIVE | LK_RETRY, td); 483 transferlockers(&vp->v_lock, vp->v_vnlock); 484 lockmgr(&vp->v_lock, LK_RELEASE, NULL, td); 485 /* 486 * Record snapshot inode. Since this is the newest snapshot, 487 * it must be placed at the end of the list. 488 */ 489 VI_LOCK(devvp); 490 fs->fs_snapinum[snaploc] = ip->i_number; 491 if (ip->i_nextsnap.tqe_prev != 0) 492 panic("ffs_snapshot: %d already on list", ip->i_number); 493 TAILQ_INSERT_TAIL(snaphead, ip, i_nextsnap); 494 devvp->v_rdev->si_copyonwrite = ffs_copyonwrite; 495 devvp->v_vflag |= VV_COPYONWRITE; 496 VI_UNLOCK(devvp); 497 ASSERT_VOP_LOCKED(vp, "ffs_snapshot vp"); 498 vp->v_vflag |= VV_SYSTEM; 499 out1: 500 /* 501 * Resume operation on filesystem. 502 */ 503 vfs_write_resume(vp->v_mount); 504 vn_start_write(NULL, &wrtmp, V_WAIT); 505 if (collectsnapstats && starttime.tv_sec > 0) { 506 nanotime(&endtime); 507 timespecsub(&endtime, &starttime); 508 printf("%s: suspended %ld.%03ld sec, redo %ld of %d\n", 509 vp->v_mount->mnt_stat.f_mntonname, (long)endtime.tv_sec, 510 endtime.tv_nsec / 1000000, redo, fs->fs_ncg); 511 } 512 if (sbp == NULL) 513 goto out; 514 /* 515 * Copy allocation information from all the snapshots in 516 * this snapshot and then expunge them from its view. 517 */ 518 snaphead = &devvp->v_rdev->si_snapshots; 519 TAILQ_FOREACH(xp, snaphead, i_nextsnap) { 520 if (xp == ip) 521 break; 522 if (xp->i_ump->um_fstype == UFS1) 523 error = expunge_ufs1(vp, xp, fs, snapacct_ufs1, 524 BLK_SNAP); 525 else 526 error = expunge_ufs2(vp, xp, fs, snapacct_ufs2, 527 BLK_SNAP); 528 if (error) { 529 fs->fs_snapinum[snaploc] = 0; 530 goto done; 531 } 532 } 533 /* 534 * Allocate the space for the list of preallocated snapshot blocks. 535 */ 536 snaplistsize = fs->fs_ncg + howmany(fs->fs_cssize, fs->fs_bsize) + 537 FSMAXSNAP + 1 /* superblock */ + 1 /* last block */ + 1 /* size */; 538 MALLOC(snapblklist, daddr_t *, snaplistsize * sizeof(daddr_t), 539 M_UFSMNT, 0); 540 ip->i_snapblklist = &snapblklist[1]; 541 /* 542 * Expunge the blocks used by the snapshots from the set of 543 * blocks marked as used in the snapshot bitmaps. Also, collect 544 * the list of allocated blocks in i_snapblklist. 545 */ 546 if (ip->i_ump->um_fstype == UFS1) 547 error = expunge_ufs1(vp, ip, copy_fs, mapacct_ufs1, BLK_SNAP); 548 else 549 error = expunge_ufs2(vp, ip, copy_fs, mapacct_ufs2, BLK_SNAP); 550 if (error) { 551 fs->fs_snapinum[snaploc] = 0; 552 FREE(snapblklist, M_UFSMNT); 553 goto done; 554 } 555 snaplistsize = ip->i_snapblklist - snapblklist; 556 snapblklist[0] = snaplistsize; 557 ip->i_snapblklist = 0; 558 /* 559 * Write out the list of allocated blocks to the end of the snapshot. 560 */ 561 auio.uio_iov = &aiov; 562 auio.uio_iovcnt = 1; 563 aiov.iov_base = (void *)snapblklist; 564 aiov.iov_len = snaplistsize * sizeof(daddr_t); 565 auio.uio_resid = aiov.iov_len;; 566 auio.uio_offset = ip->i_size; 567 auio.uio_segflg = UIO_SYSSPACE; 568 auio.uio_rw = UIO_WRITE; 569 auio.uio_td = td; 570 if ((error = VOP_WRITE(vp, &auio, IO_UNIT, td->td_ucred)) != 0) { 571 fs->fs_snapinum[snaploc] = 0; 572 FREE(snapblklist, M_UFSMNT); 573 goto done; 574 } 575 /* 576 * Write the superblock and its summary information 577 * to the snapshot. 578 */ 579 blkno = fragstoblks(fs, fs->fs_csaddr); 580 len = howmany(fs->fs_cssize, fs->fs_bsize); 581 space = copy_fs->fs_csp; 582 for (loc = 0; loc < len; loc++) { 583 error = bread(vp, blkno + loc, fs->fs_bsize, KERNCRED, &nbp); 584 if (error) { 585 brelse(nbp); 586 fs->fs_snapinum[snaploc] = 0; 587 FREE(snapblklist, M_UFSMNT); 588 goto done; 589 } 590 bcopy(space, nbp->b_data, fs->fs_bsize); 591 space = (char *)space + fs->fs_bsize; 592 bawrite(nbp); 593 } 594 /* 595 * As this is the newest list, it is the most inclusive, so 596 * should replace the previous list. 597 */ 598 VI_LOCK(devvp); 599 FREE(devvp->v_rdev->si_snapblklist, M_UFSMNT); 600 devvp->v_rdev->si_snapblklist = snapblklist; 601 devvp->v_rdev->si_snaplistsize = snaplistsize; 602 VI_UNLOCK(devvp); 603 done: 604 free(copy_fs->fs_csp, M_UFSMNT); 605 bawrite(sbp); 606 out: 607 if (saved_nice > 0) 608 td->td_ksegrp->kg_nice = saved_nice; 609 if (fs->fs_active != 0) { 610 FREE(fs->fs_active, M_DEVBUF); 611 fs->fs_active = 0; 612 } 613 mp->mnt_flag = flag; 614 if (error) 615 (void) UFS_TRUNCATE(vp, (off_t)0, 0, NOCRED, td); 616 (void) VOP_FSYNC(vp, KERNCRED, MNT_WAIT, td); 617 if (error) 618 vput(vp); 619 else 620 VOP_UNLOCK(vp, 0, td); 621 vn_finished_write(wrtmp); 622 return (error); 623 } 624 625 /* 626 * Copy a cylinder group map. All the unallocated blocks are marked 627 * BLK_NOCOPY so that the snapshot knows that it need not copy them 628 * if they are later written. If passno is one, then this is a first 629 * pass, so only setting needs to be done. If passno is 2, then this 630 * is a revision to a previous pass which must be undone as the 631 * replacement pass is done. 632 */ 633 static int 634 cgaccount(cg, vp, nbp, passno) 635 int cg; 636 struct vnode *vp; 637 struct buf *nbp; 638 int passno; 639 { 640 struct buf *bp, *ibp; 641 struct inode *ip; 642 struct cg *cgp; 643 struct fs *fs; 644 ufs2_daddr_t base, numblks; 645 int error, len, loc, indiroff; 646 647 ip = VTOI(vp); 648 fs = ip->i_fs; 649 error = bread(ip->i_devvp, fsbtodb(fs, cgtod(fs, cg)), 650 (int)fs->fs_cgsize, KERNCRED, &bp); 651 if (error) { 652 brelse(bp); 653 return (error); 654 } 655 cgp = (struct cg *)bp->b_data; 656 if (!cg_chkmagic(cgp)) { 657 brelse(bp); 658 return (EIO); 659 } 660 atomic_set_int(&ACTIVECGNUM(fs, cg), ACTIVECGOFF(cg)); 661 bcopy(bp->b_data, nbp->b_data, fs->fs_cgsize); 662 if (fs->fs_cgsize < fs->fs_bsize) 663 bzero(&nbp->b_data[fs->fs_cgsize], 664 fs->fs_bsize - fs->fs_cgsize); 665 if (passno == 2) 666 nbp->b_flags |= B_VALIDSUSPWRT; 667 numblks = howmany(fs->fs_size, fs->fs_frag); 668 len = howmany(fs->fs_fpg, fs->fs_frag); 669 base = cg * fs->fs_fpg / fs->fs_frag; 670 if (base + len >= numblks) 671 len = numblks - base - 1; 672 loc = 0; 673 if (base < NDADDR) { 674 for ( ; loc < NDADDR; loc++) { 675 if (ffs_isblock(fs, cg_blksfree(cgp), loc)) 676 DIP(ip, i_db[loc]) = BLK_NOCOPY; 677 else if (passno == 2 && DIP(ip, i_db[loc])== BLK_NOCOPY) 678 DIP(ip, i_db[loc]) = 0; 679 else if (passno == 1 && DIP(ip, i_db[loc])== BLK_NOCOPY) 680 panic("ffs_snapshot: lost direct block"); 681 } 682 } 683 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)(base + loc)), 684 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp); 685 if (error) { 686 brelse(bp); 687 return (error); 688 } 689 indiroff = (base + loc - NDADDR) % NINDIR(fs); 690 for ( ; loc < len; loc++, indiroff++) { 691 if (indiroff >= NINDIR(fs)) { 692 if (passno == 2) 693 ibp->b_flags |= B_VALIDSUSPWRT; 694 bawrite(ibp); 695 error = UFS_BALLOC(vp, 696 lblktosize(fs, (off_t)(base + loc)), 697 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp); 698 if (error) { 699 brelse(bp); 700 return (error); 701 } 702 indiroff = 0; 703 } 704 if (ip->i_ump->um_fstype == UFS1) { 705 if (ffs_isblock(fs, cg_blksfree(cgp), loc)) 706 ((ufs1_daddr_t *)(ibp->b_data))[indiroff] = 707 BLK_NOCOPY; 708 else if (passno == 2 && ((ufs1_daddr_t *)(ibp->b_data)) 709 [indiroff] == BLK_NOCOPY) 710 ((ufs1_daddr_t *)(ibp->b_data))[indiroff] = 0; 711 else if (passno == 1 && ((ufs1_daddr_t *)(ibp->b_data)) 712 [indiroff] == BLK_NOCOPY) 713 panic("ffs_snapshot: lost indirect block"); 714 continue; 715 } 716 if (ffs_isblock(fs, cg_blksfree(cgp), loc)) 717 ((ufs2_daddr_t *)(ibp->b_data))[indiroff] = BLK_NOCOPY; 718 else if (passno == 2 && 719 ((ufs2_daddr_t *)(ibp->b_data)) [indiroff] == BLK_NOCOPY) 720 ((ufs2_daddr_t *)(ibp->b_data))[indiroff] = 0; 721 else if (passno == 1 && 722 ((ufs2_daddr_t *)(ibp->b_data)) [indiroff] == BLK_NOCOPY) 723 panic("ffs_snapshot: lost indirect block"); 724 } 725 bqrelse(bp); 726 if (passno == 2) 727 ibp->b_flags |= B_VALIDSUSPWRT; 728 bdwrite(ibp); 729 return (0); 730 } 731 732 /* 733 * Before expunging a snapshot inode, note all the 734 * blocks that it claims with BLK_SNAP so that fsck will 735 * be able to account for those blocks properly and so 736 * that this snapshot knows that it need not copy them 737 * if the other snapshot holding them is freed. This code 738 * is reproduced once each for UFS1 and UFS2. 739 */ 740 static int 741 expunge_ufs1(snapvp, cancelip, fs, acctfunc, expungetype) 742 struct vnode *snapvp; 743 struct inode *cancelip; 744 struct fs *fs; 745 int (*acctfunc)(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *, 746 struct fs *, ufs_lbn_t, int); 747 int expungetype; 748 { 749 int i, error, indiroff; 750 ufs_lbn_t lbn, rlbn; 751 ufs2_daddr_t len, blkno, numblks, blksperindir; 752 struct ufs1_dinode *dip; 753 struct thread *td = curthread; 754 struct buf *bp; 755 756 /* 757 * Prepare to expunge the inode. If its inode block has not 758 * yet been copied, then allocate and fill the copy. 759 */ 760 lbn = fragstoblks(fs, ino_to_fsba(fs, cancelip->i_number)); 761 blkno = 0; 762 if (lbn < NDADDR) { 763 blkno = VTOI(snapvp)->i_din1->di_db[lbn]; 764 } else { 765 td->td_proc->p_flag |= P_COWINPROGRESS; 766 error = UFS_BALLOC(snapvp, lblktosize(fs, (off_t)lbn), 767 fs->fs_bsize, KERNCRED, BA_METAONLY, &bp); 768 td->td_proc->p_flag &= ~P_COWINPROGRESS; 769 if (error) 770 return (error); 771 indiroff = (lbn - NDADDR) % NINDIR(fs); 772 blkno = ((ufs1_daddr_t *)(bp->b_data))[indiroff]; 773 bqrelse(bp); 774 } 775 if (blkno != 0) { 776 if ((error = bread(snapvp, lbn, fs->fs_bsize, KERNCRED, &bp))) 777 return (error); 778 } else { 779 error = UFS_BALLOC(snapvp, lblktosize(fs, (off_t)lbn), 780 fs->fs_bsize, KERNCRED, 0, &bp); 781 if (error) 782 return (error); 783 if ((error = readblock(bp, lbn)) != 0) 784 return (error); 785 } 786 /* 787 * Set a snapshot inode to be a zero length file, regular files 788 * to be completely unallocated. 789 */ 790 dip = (struct ufs1_dinode *)bp->b_data + 791 ino_to_fsbo(fs, cancelip->i_number); 792 if (expungetype == BLK_NOCOPY) 793 dip->di_mode = 0; 794 dip->di_size = 0; 795 dip->di_blocks = 0; 796 dip->di_flags &= ~SF_SNAPSHOT; 797 bzero(&dip->di_db[0], (NDADDR + NIADDR) * sizeof(ufs1_daddr_t)); 798 bdwrite(bp); 799 /* 800 * Now go through and expunge all the blocks in the file 801 * using the function requested. 802 */ 803 numblks = howmany(cancelip->i_size, fs->fs_bsize); 804 if ((error = (*acctfunc)(snapvp, &cancelip->i_din1->di_db[0], 805 &cancelip->i_din1->di_db[NDADDR], fs, 0, expungetype))) 806 return (error); 807 if ((error = (*acctfunc)(snapvp, &cancelip->i_din1->di_ib[0], 808 &cancelip->i_din1->di_ib[NIADDR], fs, -1, expungetype))) 809 return (error); 810 blksperindir = 1; 811 lbn = -NDADDR; 812 len = numblks - NDADDR; 813 rlbn = NDADDR; 814 for (i = 0; len > 0 && i < NIADDR; i++) { 815 error = indiracct_ufs1(snapvp, ITOV(cancelip), i, 816 cancelip->i_din1->di_ib[i], lbn, rlbn, len, 817 blksperindir, fs, acctfunc, expungetype); 818 if (error) 819 return (error); 820 blksperindir *= NINDIR(fs); 821 lbn -= blksperindir + 1; 822 len -= blksperindir; 823 rlbn += blksperindir; 824 } 825 return (0); 826 } 827 828 /* 829 * Descend an indirect block chain for vnode cancelvp accounting for all 830 * its indirect blocks in snapvp. 831 */ 832 static int 833 indiracct_ufs1(snapvp, cancelvp, level, blkno, lbn, rlbn, remblks, 834 blksperindir, fs, acctfunc, expungetype) 835 struct vnode *snapvp; 836 struct vnode *cancelvp; 837 int level; 838 ufs1_daddr_t blkno; 839 ufs_lbn_t lbn; 840 ufs_lbn_t rlbn; 841 ufs_lbn_t remblks; 842 ufs_lbn_t blksperindir; 843 struct fs *fs; 844 int (*acctfunc)(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *, 845 struct fs *, ufs_lbn_t, int); 846 int expungetype; 847 { 848 int error, num, i; 849 ufs_lbn_t subblksperindir; 850 struct indir indirs[NIADDR + 2]; 851 ufs1_daddr_t last, *bap; 852 struct buf *bp; 853 854 if ((error = ufs_getlbns(cancelvp, rlbn, indirs, &num)) != 0) 855 return (error); 856 if (lbn != indirs[num - 1 - level].in_lbn || blkno == 0 || num < 2) 857 panic("indiracct: botched params"); 858 /* 859 * We have to expand bread here since it will deadlock looking 860 * up the block number for any blocks that are not in the cache. 861 */ 862 bp = getblk(cancelvp, lbn, fs->fs_bsize, 0, 0); 863 bp->b_blkno = fsbtodb(fs, blkno); 864 if ((bp->b_flags & (B_DONE | B_DELWRI)) == 0 && 865 (error = readblock(bp, fragstoblks(fs, blkno)))) { 866 brelse(bp); 867 return (error); 868 } 869 /* 870 * Account for the block pointers in this indirect block. 871 */ 872 last = howmany(remblks, blksperindir); 873 if (last > NINDIR(fs)) 874 last = NINDIR(fs); 875 MALLOC(bap, ufs1_daddr_t *, fs->fs_bsize, M_DEVBUF, 0); 876 bcopy(bp->b_data, (caddr_t)bap, fs->fs_bsize); 877 bqrelse(bp); 878 error = (*acctfunc)(snapvp, &bap[0], &bap[last], fs, 879 level == 0 ? rlbn : -1, expungetype); 880 if (error || level == 0) 881 goto out; 882 /* 883 * Account for the block pointers in each of the indirect blocks 884 * in the levels below us. 885 */ 886 subblksperindir = blksperindir / NINDIR(fs); 887 for (lbn++, level--, i = 0; i < last; i++) { 888 error = indiracct_ufs1(snapvp, cancelvp, level, bap[i], lbn, 889 rlbn, remblks, subblksperindir, fs, acctfunc, expungetype); 890 if (error) 891 goto out; 892 rlbn += blksperindir; 893 lbn -= blksperindir; 894 remblks -= blksperindir; 895 } 896 out: 897 FREE(bap, M_DEVBUF); 898 return (error); 899 } 900 901 /* 902 * Do both snap accounting and map accounting. 903 */ 904 static int 905 fullacct_ufs1(vp, oldblkp, lastblkp, fs, lblkno, exptype) 906 struct vnode *vp; 907 ufs1_daddr_t *oldblkp, *lastblkp; 908 struct fs *fs; 909 ufs_lbn_t lblkno; 910 int exptype; /* BLK_SNAP or BLK_NOCOPY */ 911 { 912 int error; 913 914 if ((error = snapacct_ufs1(vp, oldblkp, lastblkp, fs, lblkno, exptype))) 915 return (error); 916 return (mapacct_ufs1(vp, oldblkp, lastblkp, fs, lblkno, exptype)); 917 } 918 919 /* 920 * Identify a set of blocks allocated in a snapshot inode. 921 */ 922 static int 923 snapacct_ufs1(vp, oldblkp, lastblkp, fs, lblkno, expungetype) 924 struct vnode *vp; 925 ufs1_daddr_t *oldblkp, *lastblkp; 926 struct fs *fs; 927 ufs_lbn_t lblkno; 928 int expungetype; /* BLK_SNAP or BLK_NOCOPY */ 929 { 930 struct inode *ip = VTOI(vp); 931 ufs1_daddr_t blkno, *blkp; 932 ufs_lbn_t lbn; 933 struct buf *ibp; 934 int error; 935 936 for ( ; oldblkp < lastblkp; oldblkp++) { 937 blkno = *oldblkp; 938 if (blkno == 0 || blkno == BLK_NOCOPY || blkno == BLK_SNAP) 939 continue; 940 lbn = fragstoblks(fs, blkno); 941 if (lbn < NDADDR) { 942 blkp = &ip->i_din1->di_db[lbn]; 943 ip->i_flag |= IN_CHANGE | IN_UPDATE; 944 } else { 945 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)lbn), 946 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp); 947 if (error) 948 return (error); 949 blkp = &((ufs1_daddr_t *)(ibp->b_data)) 950 [(lbn - NDADDR) % NINDIR(fs)]; 951 } 952 /* 953 * If we are expunging a snapshot vnode and we 954 * find a block marked BLK_NOCOPY, then it is 955 * one that has been allocated to this snapshot after 956 * we took our current snapshot and can be ignored. 957 */ 958 if (expungetype == BLK_SNAP && *blkp == BLK_NOCOPY) { 959 if (lbn >= NDADDR) 960 brelse(ibp); 961 } else { 962 if (*blkp != 0) 963 panic("snapacct: bad block"); 964 *blkp = expungetype; 965 if (lbn >= NDADDR) 966 bdwrite(ibp); 967 } 968 } 969 return (0); 970 } 971 972 /* 973 * Account for a set of blocks allocated in a snapshot inode. 974 */ 975 static int 976 mapacct_ufs1(vp, oldblkp, lastblkp, fs, lblkno, expungetype) 977 struct vnode *vp; 978 ufs1_daddr_t *oldblkp, *lastblkp; 979 struct fs *fs; 980 ufs_lbn_t lblkno; 981 int expungetype; 982 { 983 ufs1_daddr_t blkno; 984 struct inode *ip; 985 ino_t inum; 986 int acctit; 987 988 ip = VTOI(vp); 989 inum = ip->i_number; 990 if (lblkno == -1) 991 acctit = 0; 992 else 993 acctit = 1; 994 for ( ; oldblkp < lastblkp; oldblkp++, lblkno++) { 995 blkno = *oldblkp; 996 if (blkno == 0 || blkno == BLK_NOCOPY) 997 continue; 998 if (acctit && expungetype == BLK_SNAP && blkno != BLK_SNAP) 999 *ip->i_snapblklist++ = lblkno; 1000 if (blkno == BLK_SNAP) 1001 blkno = blkstofrags(fs, lblkno); 1002 ffs_blkfree(fs, vp, blkno, fs->fs_bsize, inum); 1003 } 1004 return (0); 1005 } 1006 1007 /* 1008 * Before expunging a snapshot inode, note all the 1009 * blocks that it claims with BLK_SNAP so that fsck will 1010 * be able to account for those blocks properly and so 1011 * that this snapshot knows that it need not copy them 1012 * if the other snapshot holding them is freed. This code 1013 * is reproduced once each for UFS1 and UFS2. 1014 */ 1015 static int 1016 expunge_ufs2(snapvp, cancelip, fs, acctfunc, expungetype) 1017 struct vnode *snapvp; 1018 struct inode *cancelip; 1019 struct fs *fs; 1020 int (*acctfunc)(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *, 1021 struct fs *, ufs_lbn_t, int); 1022 int expungetype; 1023 { 1024 int i, error, indiroff; 1025 ufs_lbn_t lbn, rlbn; 1026 ufs2_daddr_t len, blkno, numblks, blksperindir; 1027 struct ufs2_dinode *dip; 1028 struct thread *td = curthread; 1029 struct buf *bp; 1030 1031 /* 1032 * Prepare to expunge the inode. If its inode block has not 1033 * yet been copied, then allocate and fill the copy. 1034 */ 1035 lbn = fragstoblks(fs, ino_to_fsba(fs, cancelip->i_number)); 1036 blkno = 0; 1037 if (lbn < NDADDR) { 1038 blkno = VTOI(snapvp)->i_din2->di_db[lbn]; 1039 } else { 1040 td->td_proc->p_flag |= P_COWINPROGRESS; 1041 error = UFS_BALLOC(snapvp, lblktosize(fs, (off_t)lbn), 1042 fs->fs_bsize, KERNCRED, BA_METAONLY, &bp); 1043 td->td_proc->p_flag &= ~P_COWINPROGRESS; 1044 if (error) 1045 return (error); 1046 indiroff = (lbn - NDADDR) % NINDIR(fs); 1047 blkno = ((ufs2_daddr_t *)(bp->b_data))[indiroff]; 1048 bqrelse(bp); 1049 } 1050 if (blkno != 0) { 1051 if ((error = bread(snapvp, lbn, fs->fs_bsize, KERNCRED, &bp))) 1052 return (error); 1053 } else { 1054 error = UFS_BALLOC(snapvp, lblktosize(fs, (off_t)lbn), 1055 fs->fs_bsize, KERNCRED, 0, &bp); 1056 if (error) 1057 return (error); 1058 if ((error = readblock(bp, lbn)) != 0) 1059 return (error); 1060 } 1061 /* 1062 * Set a snapshot inode to be a zero length file, regular files 1063 * to be completely unallocated. 1064 */ 1065 dip = (struct ufs2_dinode *)bp->b_data + 1066 ino_to_fsbo(fs, cancelip->i_number); 1067 if (expungetype == BLK_NOCOPY) 1068 dip->di_mode = 0; 1069 dip->di_size = 0; 1070 dip->di_blocks = 0; 1071 dip->di_flags &= ~SF_SNAPSHOT; 1072 bzero(&dip->di_db[0], (NDADDR + NIADDR) * sizeof(ufs2_daddr_t)); 1073 bdwrite(bp); 1074 /* 1075 * Now go through and expunge all the blocks in the file 1076 * using the function requested. 1077 */ 1078 numblks = howmany(cancelip->i_size, fs->fs_bsize); 1079 if ((error = (*acctfunc)(snapvp, &cancelip->i_din2->di_db[0], 1080 &cancelip->i_din2->di_db[NDADDR], fs, 0, expungetype))) 1081 return (error); 1082 if ((error = (*acctfunc)(snapvp, &cancelip->i_din2->di_ib[0], 1083 &cancelip->i_din2->di_ib[NIADDR], fs, -1, expungetype))) 1084 return (error); 1085 blksperindir = 1; 1086 lbn = -NDADDR; 1087 len = numblks - NDADDR; 1088 rlbn = NDADDR; 1089 for (i = 0; len > 0 && i < NIADDR; i++) { 1090 error = indiracct_ufs2(snapvp, ITOV(cancelip), i, 1091 cancelip->i_din2->di_ib[i], lbn, rlbn, len, 1092 blksperindir, fs, acctfunc, expungetype); 1093 if (error) 1094 return (error); 1095 blksperindir *= NINDIR(fs); 1096 lbn -= blksperindir + 1; 1097 len -= blksperindir; 1098 rlbn += blksperindir; 1099 } 1100 return (0); 1101 } 1102 1103 /* 1104 * Descend an indirect block chain for vnode cancelvp accounting for all 1105 * its indirect blocks in snapvp. 1106 */ 1107 static int 1108 indiracct_ufs2(snapvp, cancelvp, level, blkno, lbn, rlbn, remblks, 1109 blksperindir, fs, acctfunc, expungetype) 1110 struct vnode *snapvp; 1111 struct vnode *cancelvp; 1112 int level; 1113 ufs2_daddr_t blkno; 1114 ufs_lbn_t lbn; 1115 ufs_lbn_t rlbn; 1116 ufs_lbn_t remblks; 1117 ufs_lbn_t blksperindir; 1118 struct fs *fs; 1119 int (*acctfunc)(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *, 1120 struct fs *, ufs_lbn_t, int); 1121 int expungetype; 1122 { 1123 int error, num, i; 1124 ufs_lbn_t subblksperindir; 1125 struct indir indirs[NIADDR + 2]; 1126 ufs2_daddr_t last, *bap; 1127 struct buf *bp; 1128 1129 if ((error = ufs_getlbns(cancelvp, rlbn, indirs, &num)) != 0) 1130 return (error); 1131 if (lbn != indirs[num - 1 - level].in_lbn || blkno == 0 || num < 2) 1132 panic("indiracct: botched params"); 1133 /* 1134 * We have to expand bread here since it will deadlock looking 1135 * up the block number for any blocks that are not in the cache. 1136 */ 1137 bp = getblk(cancelvp, lbn, fs->fs_bsize, 0, 0); 1138 bp->b_blkno = fsbtodb(fs, blkno); 1139 if ((bp->b_flags & (B_DONE | B_DELWRI)) == 0 && 1140 (error = readblock(bp, fragstoblks(fs, blkno)))) { 1141 brelse(bp); 1142 return (error); 1143 } 1144 /* 1145 * Account for the block pointers in this indirect block. 1146 */ 1147 last = howmany(remblks, blksperindir); 1148 if (last > NINDIR(fs)) 1149 last = NINDIR(fs); 1150 MALLOC(bap, ufs2_daddr_t *, fs->fs_bsize, M_DEVBUF, 0); 1151 bcopy(bp->b_data, (caddr_t)bap, fs->fs_bsize); 1152 bqrelse(bp); 1153 error = (*acctfunc)(snapvp, &bap[0], &bap[last], fs, 1154 level == 0 ? rlbn : -1, expungetype); 1155 if (error || level == 0) 1156 goto out; 1157 /* 1158 * Account for the block pointers in each of the indirect blocks 1159 * in the levels below us. 1160 */ 1161 subblksperindir = blksperindir / NINDIR(fs); 1162 for (lbn++, level--, i = 0; i < last; i++) { 1163 error = indiracct_ufs2(snapvp, cancelvp, level, bap[i], lbn, 1164 rlbn, remblks, subblksperindir, fs, acctfunc, expungetype); 1165 if (error) 1166 goto out; 1167 rlbn += blksperindir; 1168 lbn -= blksperindir; 1169 remblks -= blksperindir; 1170 } 1171 out: 1172 FREE(bap, M_DEVBUF); 1173 return (error); 1174 } 1175 1176 /* 1177 * Do both snap accounting and map accounting. 1178 */ 1179 static int 1180 fullacct_ufs2(vp, oldblkp, lastblkp, fs, lblkno, exptype) 1181 struct vnode *vp; 1182 ufs2_daddr_t *oldblkp, *lastblkp; 1183 struct fs *fs; 1184 ufs_lbn_t lblkno; 1185 int exptype; /* BLK_SNAP or BLK_NOCOPY */ 1186 { 1187 int error; 1188 1189 if ((error = snapacct_ufs2(vp, oldblkp, lastblkp, fs, lblkno, exptype))) 1190 return (error); 1191 return (mapacct_ufs2(vp, oldblkp, lastblkp, fs, lblkno, exptype)); 1192 } 1193 1194 /* 1195 * Identify a set of blocks allocated in a snapshot inode. 1196 */ 1197 static int 1198 snapacct_ufs2(vp, oldblkp, lastblkp, fs, lblkno, expungetype) 1199 struct vnode *vp; 1200 ufs2_daddr_t *oldblkp, *lastblkp; 1201 struct fs *fs; 1202 ufs_lbn_t lblkno; 1203 int expungetype; /* BLK_SNAP or BLK_NOCOPY */ 1204 { 1205 struct inode *ip = VTOI(vp); 1206 ufs2_daddr_t blkno, *blkp; 1207 ufs_lbn_t lbn; 1208 struct buf *ibp; 1209 int error; 1210 1211 for ( ; oldblkp < lastblkp; oldblkp++) { 1212 blkno = *oldblkp; 1213 if (blkno == 0 || blkno == BLK_NOCOPY || blkno == BLK_SNAP) 1214 continue; 1215 lbn = fragstoblks(fs, blkno); 1216 if (lbn < NDADDR) { 1217 blkp = &ip->i_din2->di_db[lbn]; 1218 ip->i_flag |= IN_CHANGE | IN_UPDATE; 1219 } else { 1220 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)lbn), 1221 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp); 1222 if (error) 1223 return (error); 1224 blkp = &((ufs2_daddr_t *)(ibp->b_data)) 1225 [(lbn - NDADDR) % NINDIR(fs)]; 1226 } 1227 /* 1228 * If we are expunging a snapshot vnode and we 1229 * find a block marked BLK_NOCOPY, then it is 1230 * one that has been allocated to this snapshot after 1231 * we took our current snapshot and can be ignored. 1232 */ 1233 if (expungetype == BLK_SNAP && *blkp == BLK_NOCOPY) { 1234 if (lbn >= NDADDR) 1235 brelse(ibp); 1236 } else { 1237 if (*blkp != 0) 1238 panic("snapacct: bad block"); 1239 *blkp = expungetype; 1240 if (lbn >= NDADDR) 1241 bdwrite(ibp); 1242 } 1243 } 1244 return (0); 1245 } 1246 1247 /* 1248 * Account for a set of blocks allocated in a snapshot inode. 1249 */ 1250 static int 1251 mapacct_ufs2(vp, oldblkp, lastblkp, fs, lblkno, expungetype) 1252 struct vnode *vp; 1253 ufs2_daddr_t *oldblkp, *lastblkp; 1254 struct fs *fs; 1255 ufs_lbn_t lblkno; 1256 int expungetype; 1257 { 1258 ufs2_daddr_t blkno; 1259 struct inode *ip; 1260 ino_t inum; 1261 int acctit; 1262 1263 ip = VTOI(vp); 1264 inum = ip->i_number; 1265 if (lblkno == -1) 1266 acctit = 0; 1267 else 1268 acctit = 1; 1269 for ( ; oldblkp < lastblkp; oldblkp++, lblkno++) { 1270 blkno = *oldblkp; 1271 if (blkno == 0 || blkno == BLK_NOCOPY) 1272 continue; 1273 if (acctit && expungetype == BLK_SNAP && blkno != BLK_SNAP) 1274 *ip->i_snapblklist++ = lblkno; 1275 if (blkno == BLK_SNAP) 1276 blkno = blkstofrags(fs, lblkno); 1277 ffs_blkfree(fs, vp, blkno, fs->fs_bsize, inum); 1278 } 1279 return (0); 1280 } 1281 1282 /* 1283 * Decrement extra reference on snapshot when last name is removed. 1284 * It will not be freed until the last open reference goes away. 1285 */ 1286 void 1287 ffs_snapgone(ip) 1288 struct inode *ip; 1289 { 1290 struct inode *xp; 1291 struct fs *fs; 1292 int snaploc; 1293 1294 /* 1295 * Find snapshot in incore list. 1296 */ 1297 TAILQ_FOREACH(xp, &ip->i_devvp->v_rdev->si_snapshots, i_nextsnap) 1298 if (xp == ip) 1299 break; 1300 if (xp != NULL) 1301 vrele(ITOV(ip)); 1302 else if (snapdebug) 1303 printf("ffs_snapgone: lost snapshot vnode %d\n", 1304 ip->i_number); 1305 /* 1306 * Delete snapshot inode from superblock. Keep list dense. 1307 */ 1308 fs = ip->i_fs; 1309 for (snaploc = 0; snaploc < FSMAXSNAP; snaploc++) 1310 if (fs->fs_snapinum[snaploc] == ip->i_number) 1311 break; 1312 if (snaploc < FSMAXSNAP) { 1313 for (snaploc++; snaploc < FSMAXSNAP; snaploc++) { 1314 if (fs->fs_snapinum[snaploc] == 0) 1315 break; 1316 fs->fs_snapinum[snaploc - 1] = fs->fs_snapinum[snaploc]; 1317 } 1318 fs->fs_snapinum[snaploc - 1] = 0; 1319 } 1320 } 1321 1322 /* 1323 * Prepare a snapshot file for being removed. 1324 */ 1325 void 1326 ffs_snapremove(vp) 1327 struct vnode *vp; 1328 { 1329 struct inode *ip; 1330 struct vnode *devvp; 1331 struct lock *lkp; 1332 struct buf *ibp; 1333 struct fs *fs; 1334 struct thread *td = curthread; 1335 ufs2_daddr_t numblks, blkno, dblk, *snapblklist; 1336 int error, loc, last; 1337 1338 ip = VTOI(vp); 1339 fs = ip->i_fs; 1340 devvp = ip->i_devvp; 1341 /* 1342 * If active, delete from incore list (this snapshot may 1343 * already have been in the process of being deleted, so 1344 * would not have been active). 1345 * 1346 * Clear copy-on-write flag if last snapshot. 1347 */ 1348 if (ip->i_nextsnap.tqe_prev != 0) { 1349 VI_LOCK(devvp); 1350 lockmgr(&vp->v_lock, LK_INTERLOCK | LK_EXCLUSIVE, 1351 VI_MTX(devvp), td); 1352 VI_LOCK(devvp); 1353 TAILQ_REMOVE(&devvp->v_rdev->si_snapshots, ip, i_nextsnap); 1354 ip->i_nextsnap.tqe_prev = 0; 1355 lkp = vp->v_vnlock; 1356 vp->v_vnlock = &vp->v_lock; 1357 lockmgr(lkp, LK_RELEASE, NULL, td); 1358 if (TAILQ_FIRST(&devvp->v_rdev->si_snapshots) != 0) { 1359 VI_UNLOCK(devvp); 1360 } else { 1361 snapblklist = devvp->v_rdev->si_snapblklist; 1362 devvp->v_rdev->si_snapblklist = 0; 1363 devvp->v_rdev->si_snaplistsize = 0; 1364 devvp->v_rdev->si_copyonwrite = 0; 1365 devvp->v_vflag &= ~VV_COPYONWRITE; 1366 lockmgr(lkp, LK_DRAIN|LK_INTERLOCK, VI_MTX(devvp), td); 1367 lockmgr(lkp, LK_RELEASE, NULL, td); 1368 lockdestroy(lkp); 1369 FREE(lkp, M_UFSMNT); 1370 FREE(snapblklist, M_UFSMNT); 1371 } 1372 } 1373 /* 1374 * Clear all BLK_NOCOPY fields. Pass any block claims to other 1375 * snapshots that want them (see ffs_snapblkfree below). 1376 */ 1377 for (blkno = 1; blkno < NDADDR; blkno++) { 1378 dblk = DIP(ip, i_db[blkno]); 1379 if (dblk == BLK_NOCOPY || dblk == BLK_SNAP) 1380 DIP(ip, i_db[blkno]) = 0; 1381 else if ((dblk == blkstofrags(fs, blkno) && 1382 ffs_snapblkfree(fs, ip->i_devvp, dblk, fs->fs_bsize, 1383 ip->i_number))) { 1384 DIP(ip, i_blocks) -= btodb(fs->fs_bsize); 1385 DIP(ip, i_db[blkno]) = 0; 1386 } 1387 } 1388 numblks = howmany(ip->i_size, fs->fs_bsize); 1389 for (blkno = NDADDR; blkno < numblks; blkno += NINDIR(fs)) { 1390 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)blkno), 1391 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp); 1392 if (error) 1393 continue; 1394 if (fs->fs_size - blkno > NINDIR(fs)) 1395 last = NINDIR(fs); 1396 else 1397 last = fs->fs_size - blkno; 1398 for (loc = 0; loc < last; loc++) { 1399 if (ip->i_ump->um_fstype == UFS1) { 1400 dblk = ((ufs1_daddr_t *)(ibp->b_data))[loc]; 1401 if (dblk == BLK_NOCOPY || dblk == BLK_SNAP) 1402 ((ufs1_daddr_t *)(ibp->b_data))[loc]= 0; 1403 else if ((dblk == blkstofrags(fs, blkno) && 1404 ffs_snapblkfree(fs, ip->i_devvp, dblk, 1405 fs->fs_bsize, ip->i_number))) { 1406 ip->i_din1->di_blocks -= 1407 btodb(fs->fs_bsize); 1408 ((ufs1_daddr_t *)(ibp->b_data))[loc]= 0; 1409 } 1410 continue; 1411 } 1412 dblk = ((ufs2_daddr_t *)(ibp->b_data))[loc]; 1413 if (dblk == BLK_NOCOPY || dblk == BLK_SNAP) 1414 ((ufs2_daddr_t *)(ibp->b_data))[loc] = 0; 1415 else if ((dblk == blkstofrags(fs, blkno) && 1416 ffs_snapblkfree(fs, ip->i_devvp, dblk, 1417 fs->fs_bsize, ip->i_number))) { 1418 ip->i_din2->di_blocks -= btodb(fs->fs_bsize); 1419 ((ufs2_daddr_t *)(ibp->b_data))[loc] = 0; 1420 } 1421 } 1422 bawrite(ibp); 1423 } 1424 /* 1425 * Clear snapshot flag and drop reference. 1426 */ 1427 ip->i_flags &= ~SF_SNAPSHOT; 1428 DIP(ip, i_flags) = ip->i_flags; 1429 ip->i_flag |= IN_CHANGE | IN_UPDATE; 1430 } 1431 1432 /* 1433 * Notification that a block is being freed. Return zero if the free 1434 * should be allowed to proceed. Return non-zero if the snapshot file 1435 * wants to claim the block. The block will be claimed if it is an 1436 * uncopied part of one of the snapshots. It will be freed if it is 1437 * either a BLK_NOCOPY or has already been copied in all of the snapshots. 1438 * If a fragment is being freed, then all snapshots that care about 1439 * it must make a copy since a snapshot file can only claim full sized 1440 * blocks. Note that if more than one snapshot file maps the block, 1441 * we can pick one at random to claim it. Since none of the snapshots 1442 * can change, we are assurred that they will all see the same unmodified 1443 * image. When deleting a snapshot file (see ffs_snapremove above), we 1444 * must push any of these claimed blocks to one of the other snapshots 1445 * that maps it. These claimed blocks are easily identified as they will 1446 * have a block number equal to their logical block number within the 1447 * snapshot. A copied block can never have this property because they 1448 * must always have been allocated from a BLK_NOCOPY location. 1449 */ 1450 int 1451 ffs_snapblkfree(fs, devvp, bno, size, inum) 1452 struct fs *fs; 1453 struct vnode *devvp; 1454 ufs2_daddr_t bno; 1455 long size; 1456 ino_t inum; 1457 { 1458 struct buf *ibp, *cbp, *savedcbp = 0; 1459 struct thread *td = curthread; 1460 struct inode *ip; 1461 struct vnode *vp = NULL; 1462 ufs_lbn_t lbn; 1463 ufs2_daddr_t blkno; 1464 int indiroff = 0, snapshot_locked = 0, error = 0, claimedblk = 0; 1465 struct snaphead *snaphead; 1466 1467 lbn = fragstoblks(fs, bno); 1468 retry: 1469 VI_LOCK(devvp); 1470 snaphead = &devvp->v_rdev->si_snapshots; 1471 TAILQ_FOREACH(ip, snaphead, i_nextsnap) { 1472 vp = ITOV(ip); 1473 /* 1474 * Lookup block being written. 1475 */ 1476 if (lbn < NDADDR) { 1477 blkno = DIP(ip, i_db[lbn]); 1478 } else { 1479 if (snapshot_locked == 0 && 1480 lockmgr(vp->v_vnlock, 1481 LK_INTERLOCK | LK_EXCLUSIVE | LK_SLEEPFAIL, 1482 VI_MTX(devvp), td) != 0) 1483 goto retry; 1484 snapshot_locked = 1; 1485 td->td_proc->p_flag |= P_COWINPROGRESS; 1486 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)lbn), 1487 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp); 1488 td->td_proc->p_flag &= ~P_COWINPROGRESS; 1489 if (error) 1490 break; 1491 indiroff = (lbn - NDADDR) % NINDIR(fs); 1492 if (ip->i_ump->um_fstype == UFS1) 1493 blkno=((ufs1_daddr_t *)(ibp->b_data))[indiroff]; 1494 else 1495 blkno=((ufs2_daddr_t *)(ibp->b_data))[indiroff]; 1496 } 1497 /* 1498 * Check to see if block needs to be copied. 1499 */ 1500 if (blkno == 0) { 1501 /* 1502 * A block that we map is being freed. If it has not 1503 * been claimed yet, we will claim or copy it (below). 1504 */ 1505 claimedblk = 1; 1506 } else if (blkno == BLK_SNAP) { 1507 /* 1508 * No previous snapshot claimed the block, 1509 * so it will be freed and become a BLK_NOCOPY 1510 * (don't care) for us. 1511 */ 1512 if (claimedblk) 1513 panic("snapblkfree: inconsistent block type"); 1514 if (snapshot_locked == 0 && 1515 lockmgr(vp->v_vnlock, 1516 LK_INTERLOCK | LK_EXCLUSIVE | LK_NOWAIT, 1517 VI_MTX(devvp), td) != 0) { 1518 if (lbn >= NDADDR) 1519 bqrelse(ibp); 1520 vn_lock(vp, LK_EXCLUSIVE | LK_SLEEPFAIL, td); 1521 goto retry; 1522 } 1523 snapshot_locked = 1; 1524 if (lbn < NDADDR) { 1525 DIP(ip, i_db[lbn]) = BLK_NOCOPY; 1526 ip->i_flag |= IN_CHANGE | IN_UPDATE; 1527 } else if (ip->i_ump->um_fstype == UFS1) { 1528 ((ufs1_daddr_t *)(ibp->b_data))[indiroff] = 1529 BLK_NOCOPY; 1530 bdwrite(ibp); 1531 } else { 1532 ((ufs2_daddr_t *)(ibp->b_data))[indiroff] = 1533 BLK_NOCOPY; 1534 bdwrite(ibp); 1535 } 1536 continue; 1537 } else /* BLK_NOCOPY or default */ { 1538 /* 1539 * If the snapshot has already copied the block 1540 * (default), or does not care about the block, 1541 * it is not needed. 1542 */ 1543 if (lbn >= NDADDR) 1544 bqrelse(ibp); 1545 continue; 1546 } 1547 /* 1548 * If this is a full size block, we will just grab it 1549 * and assign it to the snapshot inode. Otherwise we 1550 * will proceed to copy it. See explanation for this 1551 * routine as to why only a single snapshot needs to 1552 * claim this block. 1553 */ 1554 if (snapshot_locked == 0 && 1555 lockmgr(vp->v_vnlock, 1556 LK_INTERLOCK | LK_EXCLUSIVE | LK_NOWAIT, 1557 VI_MTX(devvp), td) != 0) { 1558 if (lbn >= NDADDR) 1559 bqrelse(ibp); 1560 vn_lock(vp, LK_EXCLUSIVE | LK_SLEEPFAIL, td); 1561 goto retry; 1562 } 1563 snapshot_locked = 1; 1564 if (size == fs->fs_bsize) { 1565 #ifdef DEBUG 1566 if (snapdebug) 1567 printf("%s %d lbn %jd from inum %d\n", 1568 "Grabonremove: snapino", ip->i_number, 1569 (intmax_t)lbn, inum); 1570 #endif 1571 if (lbn < NDADDR) { 1572 DIP(ip, i_db[lbn]) = bno; 1573 } else if (ip->i_ump->um_fstype == UFS1) { 1574 ((ufs1_daddr_t *)(ibp->b_data))[indiroff] = bno; 1575 bdwrite(ibp); 1576 } else { 1577 ((ufs2_daddr_t *)(ibp->b_data))[indiroff] = bno; 1578 bdwrite(ibp); 1579 } 1580 DIP(ip, i_blocks) += btodb(size); 1581 ip->i_flag |= IN_CHANGE | IN_UPDATE; 1582 VOP_UNLOCK(vp, 0, td); 1583 return (1); 1584 } 1585 if (lbn >= NDADDR) 1586 bqrelse(ibp); 1587 /* 1588 * Allocate the block into which to do the copy. Note that this 1589 * allocation will never require any additional allocations for 1590 * the snapshot inode. 1591 */ 1592 td->td_proc->p_flag |= P_COWINPROGRESS; 1593 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)lbn), 1594 fs->fs_bsize, KERNCRED, 0, &cbp); 1595 td->td_proc->p_flag &= ~P_COWINPROGRESS; 1596 if (error) 1597 break; 1598 #ifdef DEBUG 1599 if (snapdebug) 1600 printf("%s%d lbn %jd %s %d size %ld to blkno %jd\n", 1601 "Copyonremove: snapino ", ip->i_number, 1602 (intmax_t)lbn, "for inum", inum, size, 1603 (intmax_t)cbp->b_blkno); 1604 #endif 1605 /* 1606 * If we have already read the old block contents, then 1607 * simply copy them to the new block. Note that we need 1608 * to synchronously write snapshots that have not been 1609 * unlinked, and hence will be visible after a crash, 1610 * to ensure their integrity. 1611 */ 1612 if (savedcbp != 0) { 1613 bcopy(savedcbp->b_data, cbp->b_data, fs->fs_bsize); 1614 bawrite(cbp); 1615 if (dopersistence && ip->i_effnlink > 0) 1616 (void) VOP_FSYNC(vp, KERNCRED, MNT_WAIT, td); 1617 continue; 1618 } 1619 /* 1620 * Otherwise, read the old block contents into the buffer. 1621 */ 1622 if ((error = readblock(cbp, lbn)) != 0) { 1623 bzero(cbp->b_data, fs->fs_bsize); 1624 bawrite(cbp); 1625 if (dopersistence && ip->i_effnlink > 0) 1626 (void) VOP_FSYNC(vp, KERNCRED, MNT_WAIT, td); 1627 break; 1628 } 1629 savedcbp = cbp; 1630 } 1631 /* 1632 * Note that we need to synchronously write snapshots that 1633 * have not been unlinked, and hence will be visible after 1634 * a crash, to ensure their integrity. 1635 */ 1636 if (savedcbp) { 1637 vp = savedcbp->b_vp; 1638 bawrite(savedcbp); 1639 if (dopersistence && VTOI(vp)->i_effnlink > 0) 1640 (void) VOP_FSYNC(vp, KERNCRED, MNT_WAIT, td); 1641 } 1642 /* 1643 * If we have been unable to allocate a block in which to do 1644 * the copy, then return non-zero so that the fragment will 1645 * not be freed. Although space will be lost, the snapshot 1646 * will stay consistent. 1647 */ 1648 if (snapshot_locked) 1649 VOP_UNLOCK(vp, 0, td); 1650 else 1651 VI_UNLOCK(devvp); 1652 return (error); 1653 } 1654 1655 /* 1656 * Associate snapshot files when mounting. 1657 */ 1658 void 1659 ffs_snapshot_mount(mp) 1660 struct mount *mp; 1661 { 1662 struct ufsmount *ump = VFSTOUFS(mp); 1663 struct vnode *devvp = ump->um_devvp; 1664 struct fs *fs = ump->um_fs; 1665 struct thread *td = curthread; 1666 struct snaphead *snaphead; 1667 struct vnode *vp; 1668 struct inode *ip, *xp; 1669 struct uio auio; 1670 struct iovec aiov; 1671 void *snapblklist; 1672 char *reason; 1673 daddr_t snaplistsize; 1674 int error, snaploc, loc; 1675 1676 /* 1677 * XXX The following needs to be set before UFS_TRUNCATE or 1678 * VOP_READ can be called. 1679 */ 1680 mp->mnt_stat.f_iosize = fs->fs_bsize; 1681 /* 1682 * Process each snapshot listed in the superblock. 1683 */ 1684 vp = NULL; 1685 snaphead = &devvp->v_rdev->si_snapshots; 1686 for (snaploc = 0; snaploc < FSMAXSNAP; snaploc++) { 1687 if (fs->fs_snapinum[snaploc] == 0) 1688 break; 1689 if ((error = VFS_VGET(mp, fs->fs_snapinum[snaploc], 1690 LK_EXCLUSIVE, &vp)) != 0){ 1691 printf("ffs_snapshot_mount: vget failed %d\n", error); 1692 continue; 1693 } 1694 ip = VTOI(vp); 1695 if ((ip->i_flags & SF_SNAPSHOT) == 0 || ip->i_size == 1696 lblktosize(fs, howmany(fs->fs_size, fs->fs_frag))) { 1697 if ((ip->i_flags & SF_SNAPSHOT) == 0) { 1698 reason = "non-snapshot"; 1699 } else { 1700 reason = "old format snapshot"; 1701 (void)UFS_TRUNCATE(vp, (off_t)0, 0, NOCRED, td); 1702 (void)VOP_FSYNC(vp, KERNCRED, MNT_WAIT, td); 1703 } 1704 printf("ffs_snapshot_mount: %s inode %d\n", 1705 reason, fs->fs_snapinum[snaploc]); 1706 vput(vp); 1707 vp = NULL; 1708 for (loc = snaploc + 1; loc < FSMAXSNAP; loc++) { 1709 if (fs->fs_snapinum[loc] == 0) 1710 break; 1711 fs->fs_snapinum[loc - 1] = fs->fs_snapinum[loc]; 1712 } 1713 fs->fs_snapinum[loc - 1] = 0; 1714 snaploc--; 1715 continue; 1716 } 1717 /* 1718 * If there already exist snapshots on this filesystem, grab a 1719 * reference to their shared lock. If this is the first snapshot 1720 * on this filesystem, we need to allocate a lock for the 1721 * snapshots to share. In either case, acquire the snapshot 1722 * lock and give up our original private lock. 1723 */ 1724 VI_LOCK(devvp); 1725 if ((xp = TAILQ_FIRST(snaphead)) != NULL) { 1726 VI_LOCK(vp); 1727 vp->v_vnlock = ITOV(xp)->v_vnlock; 1728 VI_UNLOCK(devvp); 1729 } else { 1730 struct lock *lkp; 1731 1732 VI_UNLOCK(devvp); 1733 MALLOC(lkp, struct lock *, sizeof(struct lock), 1734 M_UFSMNT, 0); 1735 lockinit(lkp, PVFS, "snaplk", VLKTIMEOUT, 1736 LK_CANRECURSE | LK_NOPAUSE); 1737 VI_LOCK(vp); 1738 vp->v_vnlock = lkp; 1739 } 1740 vn_lock(vp, LK_INTERLOCK | LK_EXCLUSIVE | LK_RETRY, td); 1741 transferlockers(&vp->v_lock, vp->v_vnlock); 1742 lockmgr(&vp->v_lock, LK_RELEASE, NULL, td); 1743 /* 1744 * Link it onto the active snapshot list. 1745 */ 1746 VI_LOCK(devvp); 1747 if (ip->i_nextsnap.tqe_prev != 0) 1748 panic("ffs_snapshot_mount: %d already on list", 1749 ip->i_number); 1750 else 1751 TAILQ_INSERT_TAIL(snaphead, ip, i_nextsnap); 1752 vp->v_vflag |= VV_SYSTEM; 1753 VI_UNLOCK(devvp); 1754 VOP_UNLOCK(vp, 0, td); 1755 } 1756 /* 1757 * No usable snapshots found. 1758 */ 1759 if (vp == NULL) 1760 return; 1761 /* 1762 * Allocate the space for the block hints list. We always want to 1763 * use the list from the newest snapshot. 1764 */ 1765 auio.uio_iov = &aiov; 1766 auio.uio_iovcnt = 1; 1767 aiov.iov_base = (void *)&snaplistsize; 1768 aiov.iov_len = sizeof(snaplistsize); 1769 auio.uio_resid = aiov.iov_len; 1770 auio.uio_offset = 1771 lblktosize(fs, howmany(fs->fs_size, fs->fs_frag)); 1772 auio.uio_segflg = UIO_SYSSPACE; 1773 auio.uio_rw = UIO_READ; 1774 auio.uio_td = td; 1775 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); 1776 if ((error = VOP_READ(vp, &auio, IO_UNIT, td->td_ucred)) != 0) { 1777 printf("ffs_snapshot_mount: read_1 failed %d\n", error); 1778 VOP_UNLOCK(vp, 0, td); 1779 return; 1780 } 1781 MALLOC(snapblklist, void *, snaplistsize * sizeof(daddr_t), 1782 M_UFSMNT, 0); 1783 auio.uio_iovcnt = 1; 1784 aiov.iov_base = snapblklist; 1785 aiov.iov_len = snaplistsize * sizeof (daddr_t); 1786 auio.uio_resid = aiov.iov_len; 1787 auio.uio_offset -= sizeof(snaplistsize); 1788 if ((error = VOP_READ(vp, &auio, IO_UNIT, td->td_ucred)) != 0) { 1789 printf("ffs_snapshot_mount: read_2 failed %d\n", error); 1790 VOP_UNLOCK(vp, 0, td); 1791 FREE(snapblklist, M_UFSMNT); 1792 return; 1793 } 1794 VOP_UNLOCK(vp, 0, td); 1795 VI_LOCK(devvp); 1796 ASSERT_VOP_LOCKED(devvp, "ffs_snapshot_mount"); 1797 devvp->v_rdev->si_snaplistsize = snaplistsize; 1798 devvp->v_rdev->si_snapblklist = (daddr_t *)snapblklist; 1799 devvp->v_rdev->si_copyonwrite = ffs_copyonwrite; 1800 devvp->v_vflag |= VV_COPYONWRITE; 1801 VI_UNLOCK(devvp); 1802 } 1803 1804 /* 1805 * Disassociate snapshot files when unmounting. 1806 */ 1807 void 1808 ffs_snapshot_unmount(mp) 1809 struct mount *mp; 1810 { 1811 struct vnode *devvp = VFSTOUFS(mp)->um_devvp; 1812 struct snaphead *snaphead = &devvp->v_rdev->si_snapshots; 1813 struct lock *lkp = NULL; 1814 struct inode *xp; 1815 struct vnode *vp; 1816 1817 VI_LOCK(devvp); 1818 while ((xp = TAILQ_FIRST(snaphead)) != 0) { 1819 vp = ITOV(xp); 1820 lkp = vp->v_vnlock; 1821 vp->v_vnlock = &vp->v_lock; 1822 TAILQ_REMOVE(snaphead, xp, i_nextsnap); 1823 xp->i_nextsnap.tqe_prev = 0; 1824 if (xp->i_effnlink > 0) { 1825 VI_UNLOCK(devvp); 1826 vrele(vp); 1827 VI_LOCK(devvp); 1828 } 1829 } 1830 if (devvp->v_rdev->si_snapblklist != NULL) { 1831 FREE(devvp->v_rdev->si_snapblklist, M_UFSMNT); 1832 devvp->v_rdev->si_snapblklist = NULL; 1833 devvp->v_rdev->si_snaplistsize = 0; 1834 } 1835 if (lkp != NULL) { 1836 lockdestroy(lkp); 1837 FREE(lkp, M_UFSMNT); 1838 } 1839 ASSERT_VOP_LOCKED(devvp, "ffs_snapshot_unmount"); 1840 devvp->v_rdev->si_copyonwrite = 0; 1841 devvp->v_vflag &= ~VV_COPYONWRITE; 1842 VI_UNLOCK(devvp); 1843 } 1844 1845 /* 1846 * Check for need to copy block that is about to be written, 1847 * copying the block if necessary. 1848 */ 1849 static int 1850 ffs_copyonwrite(devvp, bp) 1851 struct vnode *devvp; 1852 struct buf *bp; 1853 { 1854 struct snaphead *snaphead; 1855 struct buf *ibp, *cbp, *savedcbp = 0; 1856 struct thread *td = curthread; 1857 struct fs *fs; 1858 struct inode *ip; 1859 struct vnode *vp = 0; 1860 ufs2_daddr_t lbn, blkno, *snapblklist; 1861 int lower, upper, mid, indiroff, snapshot_locked = 0, error = 0; 1862 1863 if (td->td_proc->p_flag & P_COWINPROGRESS) 1864 panic("ffs_copyonwrite: recursive call"); 1865 /* 1866 * First check to see if it is in the preallocated list. 1867 * By doing this check we avoid several potential deadlocks. 1868 */ 1869 VI_LOCK(devvp); 1870 snaphead = &devvp->v_rdev->si_snapshots; 1871 ip = TAILQ_FIRST(snaphead); 1872 fs = ip->i_fs; 1873 lbn = fragstoblks(fs, dbtofsb(fs, bp->b_blkno)); 1874 snapblklist = devvp->v_rdev->si_snapblklist; 1875 upper = devvp->v_rdev->si_snaplistsize - 1; 1876 lower = 1; 1877 while (lower <= upper) { 1878 mid = (lower + upper) / 2; 1879 if (snapblklist[mid] == lbn) 1880 break; 1881 if (snapblklist[mid] < lbn) 1882 lower = mid + 1; 1883 else 1884 upper = mid - 1; 1885 } 1886 if (lower <= upper) { 1887 VI_UNLOCK(devvp); 1888 return (0); 1889 } 1890 /* 1891 * Not in the precomputed list, so check the snapshots. 1892 */ 1893 retry: 1894 TAILQ_FOREACH(ip, snaphead, i_nextsnap) { 1895 vp = ITOV(ip); 1896 /* 1897 * We ensure that everything of our own that needs to be 1898 * copied will be done at the time that ffs_snapshot is 1899 * called. Thus we can skip the check here which can 1900 * deadlock in doing the lookup in UFS_BALLOC. 1901 */ 1902 if (bp->b_vp == vp) 1903 continue; 1904 /* 1905 * Check to see if block needs to be copied. We do not have 1906 * to hold the snapshot lock while doing this lookup as it 1907 * will never require any additional allocations for the 1908 * snapshot inode. 1909 */ 1910 if (lbn < NDADDR) { 1911 blkno = DIP(ip, i_db[lbn]); 1912 } else { 1913 if (snapshot_locked == 0 && 1914 lockmgr(vp->v_vnlock, 1915 LK_INTERLOCK | LK_EXCLUSIVE | LK_SLEEPFAIL, 1916 VI_MTX(devvp), td) != 0) { 1917 VI_LOCK(devvp); 1918 goto retry; 1919 } 1920 snapshot_locked = 1; 1921 td->td_proc->p_flag |= P_COWINPROGRESS; 1922 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)lbn), 1923 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp); 1924 td->td_proc->p_flag &= ~P_COWINPROGRESS; 1925 if (error) 1926 break; 1927 indiroff = (lbn - NDADDR) % NINDIR(fs); 1928 if (ip->i_ump->um_fstype == UFS1) 1929 blkno=((ufs1_daddr_t *)(ibp->b_data))[indiroff]; 1930 else 1931 blkno=((ufs2_daddr_t *)(ibp->b_data))[indiroff]; 1932 bqrelse(ibp); 1933 } 1934 #ifdef DIAGNOSTIC 1935 if (blkno == BLK_SNAP && bp->b_lblkno >= 0) 1936 panic("ffs_copyonwrite: bad copy block"); 1937 #endif 1938 if (blkno != 0) 1939 continue; 1940 /* 1941 * Allocate the block into which to do the copy. Since 1942 * multiple processes may all try to copy the same block, 1943 * we have to recheck our need to do a copy if we sleep 1944 * waiting for the lock. 1945 * 1946 * Because all snapshots on a filesystem share a single 1947 * lock, we ensure that we will never be in competition 1948 * with another process to allocate a block. 1949 */ 1950 if (snapshot_locked == 0 && 1951 lockmgr(vp->v_vnlock, 1952 LK_INTERLOCK | LK_EXCLUSIVE | LK_SLEEPFAIL, 1953 VI_MTX(devvp), td) != 0) { 1954 VI_LOCK(devvp); 1955 goto retry; 1956 } 1957 snapshot_locked = 1; 1958 td->td_proc->p_flag |= P_COWINPROGRESS; 1959 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)lbn), 1960 fs->fs_bsize, KERNCRED, 0, &cbp); 1961 td->td_proc->p_flag &= ~P_COWINPROGRESS; 1962 if (error) 1963 break; 1964 #ifdef DEBUG 1965 if (snapdebug) { 1966 printf("Copyonwrite: snapino %d lbn %jd for ", 1967 ip->i_number, (intmax_t)lbn); 1968 if (bp->b_vp == devvp) 1969 printf("fs metadata"); 1970 else 1971 printf("inum %d", VTOI(bp->b_vp)->i_number); 1972 printf(" lblkno %jd to blkno %jd\n", 1973 (intmax_t)bp->b_lblkno, (intmax_t)cbp->b_blkno); 1974 } 1975 #endif 1976 /* 1977 * If we have already read the old block contents, then 1978 * simply copy them to the new block. Note that we need 1979 * to synchronously write snapshots that have not been 1980 * unlinked, and hence will be visible after a crash, 1981 * to ensure their integrity. 1982 */ 1983 if (savedcbp != 0) { 1984 bcopy(savedcbp->b_data, cbp->b_data, fs->fs_bsize); 1985 bawrite(cbp); 1986 if (dopersistence && ip->i_effnlink > 0) 1987 (void) VOP_FSYNC(vp, KERNCRED, MNT_WAIT, td); 1988 continue; 1989 } 1990 /* 1991 * Otherwise, read the old block contents into the buffer. 1992 */ 1993 if ((error = readblock(cbp, lbn)) != 0) { 1994 bzero(cbp->b_data, fs->fs_bsize); 1995 bawrite(cbp); 1996 if (dopersistence && ip->i_effnlink > 0) 1997 (void) VOP_FSYNC(vp, KERNCRED, MNT_WAIT, td); 1998 break; 1999 } 2000 savedcbp = cbp; 2001 } 2002 /* 2003 * Note that we need to synchronously write snapshots that 2004 * have not been unlinked, and hence will be visible after 2005 * a crash, to ensure their integrity. 2006 */ 2007 if (savedcbp) { 2008 vp = savedcbp->b_vp; 2009 bawrite(savedcbp); 2010 if (dopersistence && VTOI(vp)->i_effnlink > 0) 2011 (void) VOP_FSYNC(vp, KERNCRED, MNT_WAIT, td); 2012 } 2013 if (snapshot_locked) 2014 VOP_UNLOCK(vp, 0, td); 2015 else 2016 VI_UNLOCK(devvp); 2017 return (error); 2018 } 2019 2020 /* 2021 * Read the specified block into the given buffer. 2022 * Much of this boiler-plate comes from bwrite(). 2023 */ 2024 static int 2025 readblock(bp, lbn) 2026 struct buf *bp; 2027 ufs2_daddr_t lbn; 2028 { 2029 struct uio auio; 2030 struct iovec aiov; 2031 struct thread *td = curthread; 2032 struct inode *ip = VTOI(bp->b_vp); 2033 2034 aiov.iov_base = bp->b_data; 2035 aiov.iov_len = bp->b_bcount; 2036 auio.uio_iov = &aiov; 2037 auio.uio_iovcnt = 1; 2038 auio.uio_offset = dbtob(fsbtodb(ip->i_fs, blkstofrags(ip->i_fs, lbn))); 2039 auio.uio_resid = bp->b_bcount; 2040 auio.uio_rw = UIO_READ; 2041 auio.uio_segflg = UIO_SYSSPACE; 2042 auio.uio_td = td; 2043 return (physio(ip->i_devvp->v_rdev, &auio, 0)); 2044 } 2045