1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright 2000 Marshall Kirk McKusick. All Rights Reserved. 5 * 6 * Further information about snapshots can be obtained from: 7 * 8 * Marshall Kirk McKusick http://www.mckusick.com/softdep/ 9 * 1614 Oxford Street mckusick@mckusick.com 10 * Berkeley, CA 94709-1608 +1-510-843-9542 11 * USA 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 23 * THIS SOFTWARE IS PROVIDED BY MARSHALL KIRK MCKUSICK ``AS IS'' AND ANY 24 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 25 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 26 * DISCLAIMED. IN NO EVENT SHALL MARSHALL KIRK MCKUSICK BE LIABLE FOR 27 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #include <sys/cdefs.h> 37 #include "opt_quota.h" 38 39 #include <sys/param.h> 40 #include <sys/kernel.h> 41 #include <sys/systm.h> 42 #include <sys/conf.h> 43 #include <sys/gsb_crc32.h> 44 #include <sys/bio.h> 45 #include <sys/buf.h> 46 #include <sys/fcntl.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/rwlock.h> 56 #include <sys/vnode.h> 57 58 #include <vm/vm.h> 59 #include <vm/vm_extern.h> 60 61 #include <geom/geom.h> 62 #include <geom/geom_vfs.h> 63 64 #include <ufs/ufs/extattr.h> 65 #include <ufs/ufs/quota.h> 66 #include <ufs/ufs/ufsmount.h> 67 #include <ufs/ufs/inode.h> 68 #include <ufs/ufs/ufs_extern.h> 69 70 #include <ufs/ffs/fs.h> 71 #include <ufs/ffs/ffs_extern.h> 72 73 #define KERNCRED thread0.td_ucred 74 75 #include "opt_ffs.h" 76 77 #ifdef NO_FFS_SNAPSHOT 78 int 79 ffs_snapshot(struct mount *mp, char *snapfile) 80 { 81 return (EINVAL); 82 } 83 84 int 85 ffs_snapblkfree(struct fs *fs, 86 struct vnode *devvp, 87 ufs2_daddr_t bno, 88 long size, 89 ino_t inum, 90 __enum_uint8(vtype) vtype, 91 struct workhead *wkhd) 92 { 93 return (EINVAL); 94 } 95 96 void 97 ffs_snapremove(struct vnode *vp) 98 { 99 } 100 101 void 102 ffs_snapshot_mount(struct mount *mp) 103 { 104 } 105 106 void 107 ffs_snapshot_unmount(struct mount *mp) 108 { 109 } 110 111 void 112 ffs_snapgone(struct inode *ip) 113 { 114 } 115 116 int 117 ffs_copyonwrite(struct vnode *devvp, struct buf *bp) 118 { 119 return (EINVAL); 120 } 121 122 void 123 ffs_sync_snap(struct mount *mp, int waitfor) 124 { 125 } 126 127 #else 128 FEATURE(ffs_snapshot, "FFS snapshot support"); 129 130 LIST_HEAD(, snapdata) snapfree; 131 static struct mtx snapfree_lock; 132 MTX_SYSINIT(ffs_snapfree, &snapfree_lock, "snapdata free list", MTX_DEF); 133 134 static int cgaccount(int, struct vnode *, struct buf *, int); 135 static int expunge_ufs1(struct vnode *, struct inode *, struct fs *, 136 int (*)(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *, struct fs *, 137 ufs_lbn_t, int), int, int); 138 static int indiracct_ufs1(struct vnode *, struct vnode *, int, 139 ufs1_daddr_t, ufs_lbn_t, ufs_lbn_t, ufs_lbn_t, ufs_lbn_t, struct fs *, 140 int (*)(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *, struct fs *, 141 ufs_lbn_t, int), int); 142 static int fullacct_ufs1(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *, 143 struct fs *, ufs_lbn_t, int); 144 static int snapacct_ufs1(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *, 145 struct fs *, ufs_lbn_t, int); 146 static int mapacct_ufs1(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *, 147 struct fs *, ufs_lbn_t, int); 148 static int expunge_ufs2(struct vnode *, struct inode *, struct fs *, 149 int (*)(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *, struct fs *, 150 ufs_lbn_t, int), int, int); 151 static int indiracct_ufs2(struct vnode *, struct vnode *, int, 152 ufs2_daddr_t, ufs_lbn_t, ufs_lbn_t, ufs_lbn_t, ufs_lbn_t, struct fs *, 153 int (*)(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *, struct fs *, 154 ufs_lbn_t, int), int); 155 static int fullacct_ufs2(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *, 156 struct fs *, ufs_lbn_t, int); 157 static int snapacct_ufs2(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *, 158 struct fs *, ufs_lbn_t, int); 159 static int mapacct_ufs2(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *, 160 struct fs *, ufs_lbn_t, int); 161 static int readblock(struct vnode *vp, struct buf *, ufs2_daddr_t); 162 static void try_free_snapdata(struct vnode *devvp); 163 static void revert_snaplock(struct vnode *, struct vnode *, struct snapdata *); 164 static struct snapdata *ffs_snapdata_acquire(struct vnode *devvp); 165 static int ffs_bp_snapblk(struct vnode *, struct buf *); 166 167 /* 168 * To ensure the consistency of snapshots across crashes, we must 169 * synchronously write out copied blocks before allowing the 170 * originals to be modified. Because of the rather severe speed 171 * penalty that this imposes, the code normally only ensures 172 * persistence for the filesystem metadata contained within a 173 * snapshot. Setting the following flag allows this crash 174 * persistence to be enabled for file contents. 175 */ 176 int dopersistence = 0; 177 178 #ifdef DIAGNOSTIC 179 #include <sys/sysctl.h> 180 SYSCTL_INT(_debug, OID_AUTO, dopersistence, CTLFLAG_RW, &dopersistence, 0, ""); 181 static int snapdebug = 0; 182 SYSCTL_INT(_debug, OID_AUTO, snapdebug, CTLFLAG_RW, &snapdebug, 0, ""); 183 int collectsnapstats = 0; 184 SYSCTL_INT(_debug, OID_AUTO, collectsnapstats, CTLFLAG_RW, &collectsnapstats, 185 0, ""); 186 #endif /* DIAGNOSTIC */ 187 188 /* 189 * Create a snapshot file and initialize it for the filesystem. 190 */ 191 int 192 ffs_snapshot(struct mount *mp, char *snapfile) 193 { 194 ufs2_daddr_t numblks, blkno, *blkp, *snapblklist; 195 int error, cg, snaploc; 196 int i, size, len, loc; 197 ufs2_daddr_t blockno; 198 uint64_t flag; 199 char saved_nice = 0; 200 #ifdef DIAGNOSTIC 201 long redo = 0; 202 #endif 203 long snaplistsize = 0; 204 int32_t *lp; 205 void *space; 206 struct fs *copy_fs = NULL, *fs, *bpfs; 207 struct thread *td = curthread; 208 struct inode *ip, *xp; 209 struct buf *bp, *nbp, *ibp; 210 struct nameidata nd; 211 struct mount *wrtmp; 212 struct vattr vat; 213 struct vnode *vp, *xvp, *mvp, *devvp; 214 struct uio auio; 215 struct iovec aiov; 216 struct snapdata *sn; 217 struct ufsmount *ump; 218 #ifdef DIAGNOSTIC 219 struct timespec starttime = {0, 0}, endtime; 220 #endif 221 222 ump = VFSTOUFS(mp); 223 fs = ump->um_fs; 224 sn = NULL; 225 MNT_ILOCK(mp); 226 flag = mp->mnt_flag; 227 MNT_IUNLOCK(mp); 228 /* 229 * Need to serialize access to snapshot code per filesystem. 230 */ 231 /* 232 * Assign a snapshot slot in the superblock. 233 */ 234 UFS_LOCK(ump); 235 for (snaploc = 0; snaploc < FSMAXSNAP; snaploc++) 236 if (fs->fs_snapinum[snaploc] == 0) 237 break; 238 UFS_UNLOCK(ump); 239 if (snaploc == FSMAXSNAP) 240 return (ENOSPC); 241 /* 242 * Create the snapshot file. 243 */ 244 restart: 245 NDINIT(&nd, CREATE, LOCKPARENT | LOCKLEAF | NOCACHE, UIO_SYSSPACE, 246 snapfile); 247 if ((error = namei(&nd)) != 0) 248 return (error); 249 if (nd.ni_vp != NULL) { 250 vput(nd.ni_vp); 251 error = EEXIST; 252 } 253 if (nd.ni_dvp->v_mount != mp) 254 error = EXDEV; 255 if (error) { 256 NDFREE_PNBUF(&nd); 257 if (nd.ni_dvp == nd.ni_vp) 258 vrele(nd.ni_dvp); 259 else 260 vput(nd.ni_dvp); 261 return (error); 262 } 263 VATTR_NULL(&vat); 264 vat.va_type = VREG; 265 vat.va_mode = S_IRUSR; 266 vat.va_vaflags |= VA_EXCLUSIVE; 267 if (VOP_GETWRITEMOUNT(nd.ni_dvp, &wrtmp)) 268 wrtmp = NULL; 269 if (wrtmp != mp) 270 panic("ffs_snapshot: mount mismatch"); 271 vfs_rel(wrtmp); 272 if (vn_start_write(NULL, &wrtmp, V_NOWAIT) != 0) { 273 NDFREE_PNBUF(&nd); 274 vput(nd.ni_dvp); 275 if ((error = vn_start_write(NULL, &wrtmp, 276 V_XSLEEP | PCATCH)) != 0) 277 return (error); 278 goto restart; 279 } 280 error = VOP_CREATE(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vat); 281 if (error) { 282 VOP_VPUT_PAIR(nd.ni_dvp, NULL, true); 283 NDFREE_PNBUF(&nd); 284 vn_finished_write(wrtmp); 285 if (error == ERELOOKUP) 286 goto restart; 287 return (error); 288 } 289 vp = nd.ni_vp; 290 vref(nd.ni_dvp); 291 VOP_VPUT_PAIR(nd.ni_dvp, &vp, false); 292 if (VN_IS_DOOMED(vp)) { 293 error = EBADF; 294 goto out; 295 } 296 vnode_create_vobject(nd.ni_vp, fs->fs_size, td); 297 vp->v_vflag |= VV_SYSTEM; 298 ip = VTOI(vp); 299 devvp = ITODEVVP(ip); 300 /* 301 * Calculate the size of the filesystem then allocate the block 302 * immediately following the last block of the filesystem that 303 * will contain the snapshot list. This operation allows us to 304 * set the size of the snapshot. 305 */ 306 numblks = howmany(fs->fs_size, fs->fs_frag); 307 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)numblks), 308 fs->fs_bsize, KERNCRED, BA_CLRBUF, &bp); 309 if (error) 310 goto out; 311 bawrite(bp); 312 ip->i_size = lblktosize(fs, (off_t)(numblks + 1)); 313 vnode_pager_setsize(vp, ip->i_size); 314 DIP_SET(ip, i_size, ip->i_size); 315 UFS_INODE_SET_FLAG(ip, IN_SIZEMOD | IN_CHANGE | IN_UPDATE); 316 /* 317 * Preallocate critical data structures so that we can copy 318 * them in without further allocation after we suspend all 319 * operations on the filesystem. We would like to just release 320 * the allocated buffers without writing them since they will 321 * be filled in below once we are ready to go, but this upsets 322 * the soft update code, so we go ahead and write the new buffers. 323 * 324 * Allocate all indirect blocks and mark all of them as not 325 * needing to be copied. 326 */ 327 for (blkno = UFS_NDADDR; blkno < numblks; blkno += NINDIR(fs)) { 328 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)blkno), 329 fs->fs_bsize, td->td_ucred, BA_METAONLY, &ibp); 330 if (error) 331 goto out; 332 bawrite(ibp); 333 } 334 /* 335 * Allocate copies for the superblock and its summary information. 336 */ 337 error = UFS_BALLOC(vp, fs->fs_sblockloc, fs->fs_sbsize, KERNCRED, 338 0, &nbp); 339 if (error) 340 goto out; 341 bawrite(nbp); 342 blkno = fragstoblks(fs, fs->fs_csaddr); 343 len = howmany(fs->fs_cssize, fs->fs_bsize); 344 for (loc = 0; loc < len; loc++) { 345 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)(blkno + loc)), 346 fs->fs_bsize, KERNCRED, 0, &nbp); 347 if (error) 348 goto out; 349 bawrite(nbp); 350 } 351 /* 352 * Allocate all cylinder group blocks. 353 */ 354 for (cg = 0; cg < fs->fs_ncg; cg++) { 355 error = UFS_BALLOC(vp, lfragtosize(fs, cgtod(fs, cg)), 356 fs->fs_bsize, KERNCRED, 0, &nbp); 357 if (error) 358 goto out; 359 bawrite(nbp); 360 if (cg % 10 == 0) { 361 error = ffs_syncvnode(vp, MNT_WAIT, 0); 362 /* vp possibly reclaimed if unlocked */ 363 if (error != 0) 364 goto out; 365 } 366 } 367 /* 368 * Change inode to snapshot type file. Before setting its block 369 * pointers to BLK_SNAP and BLK_NOCOPY in cgaccount, we have to 370 * set its type to SF_SNAPSHOT so that VOP_REMOVE will know that 371 * they need to be rolled back before attempting deletion. 372 */ 373 ip->i_flags |= SF_SNAPSHOT; 374 DIP_SET(ip, i_flags, ip->i_flags); 375 UFS_INODE_SET_FLAG(ip, IN_CHANGE | IN_UPDATE); 376 /* 377 * Copy all the cylinder group maps. Although the 378 * filesystem is still active, we hope that only a few 379 * cylinder groups will change between now and when we 380 * suspend operations. Thus, we will be able to quickly 381 * touch up the few cylinder groups that changed during 382 * the suspension period. 383 */ 384 len = roundup2(howmany(fs->fs_ncg, NBBY), sizeof(uint64_t)); 385 space = malloc(len, M_DEVBUF, M_WAITOK | M_ZERO); 386 UFS_LOCK(ump); 387 fs->fs_active = space; 388 UFS_UNLOCK(ump); 389 for (cg = 0; cg < fs->fs_ncg; cg++) { 390 error = UFS_BALLOC(vp, lfragtosize(fs, cgtod(fs, cg)), 391 fs->fs_bsize, KERNCRED, 0, &nbp); 392 if (error) 393 goto out; 394 error = cgaccount(cg, vp, nbp, 1); 395 bawrite(nbp); 396 if (cg % 10 == 0 && error == 0) 397 error = ffs_syncvnode(vp, MNT_WAIT, 0); 398 if (error) 399 goto out; 400 } 401 /* 402 * Ensure that the snapshot is completely on disk. 403 * Since we have marked it as a snapshot it is safe to 404 * unlock it as no process will be allowed to write to it. 405 */ 406 if ((error = ffs_syncvnode(vp, MNT_WAIT, 0)) != 0) 407 goto out; 408 VOP_UNLOCK(vp); 409 /* 410 * All allocations are done, so we can now snapshot the system. 411 * 412 * Recind nice scheduling while running with the filesystem suspended. 413 */ 414 if (td->td_proc->p_nice > 0) { 415 struct proc *p; 416 417 p = td->td_proc; 418 PROC_LOCK(p); 419 saved_nice = p->p_nice; 420 sched_nice(p, 0); 421 PROC_UNLOCK(p); 422 } 423 /* 424 * Suspend operation on filesystem. 425 */ 426 for (;;) { 427 vn_finished_write(wrtmp); 428 if ((error = vfs_write_suspend(vp->v_mount, 0)) != 0) { 429 vn_start_write(NULL, &wrtmp, V_WAIT); 430 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 431 goto out; 432 } 433 if (mp->mnt_kern_flag & MNTK_SUSPENDED) 434 break; 435 vn_start_write(NULL, &wrtmp, V_WAIT); 436 } 437 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 438 if (ip->i_effnlink == 0) { 439 error = ENOENT; /* Snapshot file unlinked */ 440 goto resumefs; 441 } 442 #ifdef DIAGNOSTIC 443 if (collectsnapstats) 444 nanotime(&starttime); 445 #endif 446 447 /* 448 * First, copy all the cylinder group maps that have changed. 449 */ 450 for (cg = 0; cg < fs->fs_ncg; cg++) { 451 if ((ACTIVECGNUM(fs, cg) & ACTIVECGOFF(cg)) != 0) 452 continue; 453 #ifdef DIAGNOSTIC 454 redo++; 455 #endif 456 error = UFS_BALLOC(vp, lfragtosize(fs, cgtod(fs, cg)), 457 fs->fs_bsize, KERNCRED, 0, &nbp); 458 if (error) 459 goto resumefs; 460 error = cgaccount(cg, vp, nbp, 2); 461 bawrite(nbp); 462 if (error) 463 goto resumefs; 464 } 465 /* 466 * Grab a copy of the superblock and its summary information. 467 * We delay writing it until the suspension is released below. 468 */ 469 copy_fs = malloc((uint64_t)fs->fs_bsize, M_UFSMNT, M_WAITOK); 470 bcopy(fs, copy_fs, fs->fs_sbsize); 471 copy_fs->fs_si = malloc(sizeof(struct fs_summary_info), M_UFSMNT, 472 M_ZERO | M_WAITOK); 473 if ((fs->fs_flags & (FS_UNCLEAN | FS_NEEDSFSCK)) == 0) 474 copy_fs->fs_clean = 1; 475 size = fs->fs_bsize < SBLOCKSIZE ? fs->fs_bsize : SBLOCKSIZE; 476 if (fs->fs_sbsize < size) 477 bzero(&((char *)copy_fs)[fs->fs_sbsize], 478 size - fs->fs_sbsize); 479 size = blkroundup(fs, fs->fs_cssize); 480 if (fs->fs_contigsumsize > 0) 481 size += fs->fs_ncg * sizeof(int32_t); 482 space = malloc((uint64_t)size, M_UFSMNT, M_WAITOK); 483 copy_fs->fs_csp = space; 484 bcopy(fs->fs_csp, copy_fs->fs_csp, fs->fs_cssize); 485 space = (char *)space + fs->fs_cssize; 486 loc = howmany(fs->fs_cssize, fs->fs_fsize); 487 i = fs->fs_frag - loc % fs->fs_frag; 488 len = (i == fs->fs_frag) ? 0 : i * fs->fs_fsize; 489 if (len > 0) { 490 if ((error = bread(devvp, fsbtodb(fs, fs->fs_csaddr + loc), 491 len, KERNCRED, &bp)) != 0) { 492 brelse(bp); 493 goto resumefs; 494 } 495 bcopy(bp->b_data, space, (uint64_t)len); 496 space = (char *)space + len; 497 bp->b_flags |= B_INVAL | B_NOCACHE; 498 brelse(bp); 499 } 500 if (fs->fs_contigsumsize > 0) { 501 copy_fs->fs_maxcluster = lp = space; 502 for (i = 0; i < fs->fs_ncg; i++) 503 *lp++ = fs->fs_contigsumsize; 504 } 505 /* 506 * We must check for active files that have been unlinked 507 * (e.g., with a zero link count). We have to expunge all 508 * trace of these files from the snapshot so that they are 509 * not reclaimed prematurely by fsck or unnecessarily dumped. 510 * We turn off the MNTK_SUSPENDED flag to avoid a panic from 511 * spec_strategy about writing on a suspended filesystem. 512 * Note that we skip unlinked snapshot files as they will 513 * be handled separately below. 514 * 515 * We also calculate the size needed for the snapshot list. 516 * Initial number of entries is composed of: 517 * - one for each cylinder group map 518 * - one for each block used by superblock summary table 519 * - one for each snapshot inode block 520 * - one for the superblock 521 * - one for the snapshot list 522 * The direct block entries in the snapshot are always 523 * copied (see reason below). Note that the superblock and 524 * the first cylinder group will almost always be allocated 525 * in the direct blocks, but we add the slop for them in case 526 * they do not end up there. The snapshot list size may get 527 * expanded by one because of an update of an inode block for 528 * an unlinked but still open file when it is expunged. 529 * 530 * Because the direct block pointers are always copied, they 531 * are not added to the list. Instead ffs_copyonwrite() 532 * explicitly checks for them before checking the snapshot list. 533 */ 534 snaplistsize = fs->fs_ncg + howmany(fs->fs_cssize, fs->fs_bsize) + 535 FSMAXSNAP + /* superblock */ 1 + /* snaplist */ 1; 536 MNT_ILOCK(mp); 537 mp->mnt_kern_flag &= ~MNTK_SUSPENDED; 538 MNT_IUNLOCK(mp); 539 loop: 540 MNT_VNODE_FOREACH_ALL(xvp, mp, mvp) { 541 if ((xvp->v_usecount == 0 && 542 (xvp->v_iflag & (VI_OWEINACT | VI_DOINGINACT)) == 0) || 543 xvp->v_type == VNON || 544 IS_SNAPSHOT(VTOI(xvp))) { 545 VI_UNLOCK(xvp); 546 continue; 547 } 548 /* 549 * We can skip parent directory vnode because it must have 550 * this snapshot file in it. 551 */ 552 if (xvp == nd.ni_dvp) { 553 VI_UNLOCK(xvp); 554 continue; 555 } 556 vholdl(xvp); 557 if (vn_lock(xvp, LK_EXCLUSIVE | LK_INTERLOCK) != 0) { 558 MNT_VNODE_FOREACH_ALL_ABORT(mp, mvp); 559 vdrop(xvp); 560 goto loop; 561 } 562 VI_LOCK(xvp); 563 if (xvp->v_usecount == 0 && 564 (xvp->v_iflag & (VI_OWEINACT | VI_DOINGINACT)) == 0) { 565 VI_UNLOCK(xvp); 566 VOP_UNLOCK(xvp); 567 vdrop(xvp); 568 continue; 569 } 570 VI_UNLOCK(xvp); 571 #ifdef DIAGNOSTIC 572 if (snapdebug) 573 vn_printf(xvp, "ffs_snapshot: busy vnode "); 574 #endif 575 if (VOP_GETATTR(xvp, &vat, td->td_ucred) == 0 && 576 vat.va_nlink > 0) { 577 VOP_UNLOCK(xvp); 578 vdrop(xvp); 579 continue; 580 } 581 xp = VTOI(xvp); 582 if (ffs_checkfreefile(copy_fs, vp, xp->i_number)) { 583 VOP_UNLOCK(xvp); 584 vdrop(xvp); 585 continue; 586 } 587 /* 588 * If there is a fragment, clear it here. 589 */ 590 blkno = 0; 591 loc = howmany(xp->i_size, fs->fs_bsize) - 1; 592 if (loc < UFS_NDADDR) { 593 len = fragroundup(fs, blkoff(fs, xp->i_size)); 594 if (len != 0 && len < fs->fs_bsize) { 595 ffs_blkfree(ump, copy_fs, vp, 596 DIP(xp, i_db[loc]), len, xp->i_number, 597 xvp->v_type, NULL, SINGLETON_KEY); 598 blkno = DIP(xp, i_db[loc]); 599 DIP_SET(xp, i_db[loc], 0); 600 } 601 } 602 snaplistsize += 1; 603 if (I_IS_UFS1(xp)) 604 error = expunge_ufs1(vp, xp, copy_fs, fullacct_ufs1, 605 BLK_NOCOPY, 1); 606 else 607 error = expunge_ufs2(vp, xp, copy_fs, fullacct_ufs2, 608 BLK_NOCOPY, 1); 609 if (blkno) 610 DIP_SET(xp, i_db[loc], blkno); 611 if (!error) 612 error = ffs_freefile(ump, copy_fs, vp, xp->i_number, 613 xp->i_mode, NULL); 614 VOP_UNLOCK(xvp); 615 vdrop(xvp); 616 if (error) { 617 MNT_VNODE_FOREACH_ALL_ABORT(mp, mvp); 618 goto resumefs; 619 } 620 } 621 /* 622 * Erase the journal file from the snapshot. 623 */ 624 if (fs->fs_flags & FS_SUJ) { 625 error = softdep_journal_lookup(mp, &xvp); 626 if (error) 627 goto resumefs; 628 xp = VTOI(xvp); 629 if (I_IS_UFS1(xp)) 630 error = expunge_ufs1(vp, xp, copy_fs, fullacct_ufs1, 631 BLK_NOCOPY, 0); 632 else 633 error = expunge_ufs2(vp, xp, copy_fs, fullacct_ufs2, 634 BLK_NOCOPY, 0); 635 vput(xvp); 636 } 637 /* 638 * Preallocate all the direct blocks in the snapshot inode so 639 * that we never have to write the inode itself to commit an 640 * update to the contents of the snapshot. Note that once 641 * created, the size of the snapshot will never change, so 642 * there will never be a need to write the inode except to 643 * update the non-integrity-critical time fields and 644 * allocated-block count. 645 */ 646 for (blockno = 0; blockno < UFS_NDADDR; blockno++) { 647 if (DIP(ip, i_db[blockno]) != 0) 648 continue; 649 error = UFS_BALLOC(vp, lblktosize(fs, blockno), 650 fs->fs_bsize, KERNCRED, BA_CLRBUF, &bp); 651 if (error) 652 goto resumefs; 653 error = readblock(vp, bp, blockno); 654 bawrite(bp); 655 if (error != 0) 656 goto resumefs; 657 } 658 /* 659 * Acquire a lock on the snapdata structure, creating it if necessary. 660 */ 661 sn = ffs_snapdata_acquire(devvp); 662 /* 663 * Change vnode to use shared snapshot lock instead of the original 664 * private lock. 665 */ 666 vp->v_vnlock = &sn->sn_lock; 667 lockmgr(&vp->v_lock, LK_RELEASE, NULL); 668 xp = TAILQ_FIRST(&sn->sn_head); 669 /* 670 * If this is the first snapshot on this filesystem, then we need 671 * to allocate the space for the list of preallocated snapshot blocks. 672 * This list will be refined below, but this preliminary one will 673 * keep us out of deadlock until the full one is ready. 674 */ 675 if (xp == NULL) { 676 snapblklist = malloc(snaplistsize * sizeof(daddr_t), 677 M_UFSMNT, M_WAITOK); 678 blkp = &snapblklist[1]; 679 *blkp++ = lblkno(fs, fs->fs_sblockloc); 680 blkno = fragstoblks(fs, fs->fs_csaddr); 681 for (cg = 0; cg < fs->fs_ncg; cg++) { 682 if (fragstoblks(fs, cgtod(fs, cg)) > blkno) 683 break; 684 *blkp++ = fragstoblks(fs, cgtod(fs, cg)); 685 } 686 len = howmany(fs->fs_cssize, fs->fs_bsize); 687 for (loc = 0; loc < len; loc++) 688 *blkp++ = blkno + loc; 689 for (; cg < fs->fs_ncg; cg++) 690 *blkp++ = fragstoblks(fs, cgtod(fs, cg)); 691 snapblklist[0] = blkp - snapblklist; 692 VI_LOCK(devvp); 693 if (sn->sn_blklist != NULL) 694 panic("ffs_snapshot: non-empty list"); 695 sn->sn_blklist = snapblklist; 696 sn->sn_listsize = blkp - snapblklist; 697 VI_UNLOCK(devvp); 698 } 699 /* 700 * Record snapshot inode. Since this is the newest snapshot, 701 * it must be placed at the end of the list. 702 */ 703 VI_LOCK(devvp); 704 fs->fs_snapinum[snaploc] = ip->i_number; 705 if (ip->i_nextsnap.tqe_prev != 0) 706 panic("ffs_snapshot: %ju already on list", 707 (uintmax_t)ip->i_number); 708 TAILQ_INSERT_TAIL(&sn->sn_head, ip, i_nextsnap); 709 devvp->v_vflag |= VV_COPYONWRITE; 710 VI_UNLOCK(devvp); 711 resumefs: 712 ASSERT_VOP_LOCKED(vp, "ffs_snapshot vp"); 713 if (error != 0 && copy_fs != NULL) { 714 free(copy_fs->fs_csp, M_UFSMNT); 715 free(copy_fs->fs_si, M_UFSMNT); 716 free(copy_fs, M_UFSMNT); 717 copy_fs = NULL; 718 } 719 KASSERT(error != 0 || (sn != NULL && copy_fs != NULL), 720 ("missing snapshot setup parameters")); 721 /* 722 * Resume operation on filesystem. 723 */ 724 vfs_write_resume(vp->v_mount, VR_START_WRITE | VR_NO_SUSPCLR); 725 #ifdef DIAGNOSTIC 726 if (collectsnapstats && starttime.tv_sec > 0) { 727 nanotime(&endtime); 728 timespecsub(&endtime, &starttime, &endtime); 729 printf("%s: suspended %ld.%03ld sec, redo %ld of %d\n", 730 vp->v_mount->mnt_stat.f_mntonname, (long)endtime.tv_sec, 731 endtime.tv_nsec / 1000000, redo, fs->fs_ncg); 732 } 733 #endif 734 if (copy_fs == NULL) 735 goto out; 736 /* 737 * Copy allocation information from all the snapshots in 738 * this snapshot and then expunge them from its view. 739 */ 740 TAILQ_FOREACH(xp, &sn->sn_head, i_nextsnap) { 741 if (xp == ip) 742 break; 743 if (I_IS_UFS1(xp)) 744 error = expunge_ufs1(vp, xp, fs, snapacct_ufs1, 745 BLK_SNAP, 0); 746 else 747 error = expunge_ufs2(vp, xp, fs, snapacct_ufs2, 748 BLK_SNAP, 0); 749 if (error == 0 && xp->i_effnlink == 0) { 750 error = ffs_freefile(ump, 751 copy_fs, 752 vp, 753 xp->i_number, 754 xp->i_mode, NULL); 755 } 756 if (error) { 757 fs->fs_snapinum[snaploc] = 0; 758 goto done; 759 } 760 } 761 /* 762 * Allocate space for the full list of preallocated snapshot blocks. 763 */ 764 snapblklist = malloc(snaplistsize * sizeof(daddr_t), 765 M_UFSMNT, M_WAITOK); 766 ip->i_snapblklist = &snapblklist[1]; 767 /* 768 * Expunge the blocks used by the snapshots from the set of 769 * blocks marked as used in the snapshot bitmaps. Also, collect 770 * the list of allocated blocks in i_snapblklist. 771 */ 772 if (I_IS_UFS1(ip)) 773 error = expunge_ufs1(vp, ip, copy_fs, mapacct_ufs1, 774 BLK_SNAP, 0); 775 else 776 error = expunge_ufs2(vp, ip, copy_fs, mapacct_ufs2, 777 BLK_SNAP, 0); 778 if (error) { 779 fs->fs_snapinum[snaploc] = 0; 780 free(snapblklist, M_UFSMNT); 781 goto done; 782 } 783 if (snaplistsize < ip->i_snapblklist - snapblklist) 784 panic("ffs_snapshot: list too small"); 785 snaplistsize = ip->i_snapblklist - snapblklist; 786 snapblklist[0] = snaplistsize; 787 ip->i_snapblklist = 0; 788 /* 789 * Write out the list of allocated blocks to the end of the snapshot. 790 */ 791 auio.uio_iov = &aiov; 792 auio.uio_iovcnt = 1; 793 aiov.iov_base = (void *)snapblklist; 794 aiov.iov_len = snaplistsize * sizeof(daddr_t); 795 auio.uio_resid = aiov.iov_len; 796 auio.uio_offset = lblktosize(fs, (off_t)numblks); 797 auio.uio_segflg = UIO_SYSSPACE; 798 auio.uio_rw = UIO_WRITE; 799 auio.uio_td = td; 800 if ((error = VOP_WRITE(vp, &auio, IO_UNIT, td->td_ucred)) != 0) { 801 fs->fs_snapinum[snaploc] = 0; 802 free(snapblklist, M_UFSMNT); 803 goto done; 804 } 805 /* 806 * Write the superblock and its summary information 807 * to the snapshot. 808 */ 809 blkno = fragstoblks(fs, fs->fs_csaddr); 810 len = howmany(fs->fs_cssize, fs->fs_bsize); 811 space = copy_fs->fs_csp; 812 for (loc = 0; loc < len; loc++) { 813 error = bread(vp, blkno + loc, fs->fs_bsize, KERNCRED, &nbp); 814 if (error) { 815 fs->fs_snapinum[snaploc] = 0; 816 free(snapblklist, M_UFSMNT); 817 goto done; 818 } 819 bcopy(space, nbp->b_data, fs->fs_bsize); 820 space = (char *)space + fs->fs_bsize; 821 bawrite(nbp); 822 } 823 error = bread(vp, lblkno(fs, fs->fs_sblockloc), fs->fs_bsize, 824 KERNCRED, &nbp); 825 if (error) { 826 brelse(nbp); 827 } else { 828 loc = blkoff(fs, fs->fs_sblockloc); 829 copy_fs->fs_fmod = 0; 830 bpfs = (struct fs *)&nbp->b_data[loc]; 831 bcopy((caddr_t)copy_fs, (caddr_t)bpfs, (uint64_t)fs->fs_sbsize); 832 ffs_oldfscompat_write(bpfs, ump); 833 bpfs->fs_ckhash = ffs_calc_sbhash(bpfs); 834 bawrite(nbp); 835 } 836 /* 837 * As this is the newest list, it is the most inclusive, so 838 * should replace the previous list. 839 */ 840 VI_LOCK(devvp); 841 space = sn->sn_blklist; 842 sn->sn_blklist = snapblklist; 843 sn->sn_listsize = snaplistsize; 844 VI_UNLOCK(devvp); 845 if (space != NULL) 846 free(space, M_UFSMNT); 847 done: 848 free(copy_fs->fs_csp, M_UFSMNT); 849 free(copy_fs->fs_si, M_UFSMNT); 850 free(copy_fs, M_UFSMNT); 851 copy_fs = NULL; 852 out: 853 if (saved_nice > 0) { 854 struct proc *p; 855 856 p = td->td_proc; 857 PROC_LOCK(p); 858 sched_nice(td->td_proc, saved_nice); 859 PROC_UNLOCK(td->td_proc); 860 } 861 UFS_LOCK(ump); 862 if (fs->fs_active != 0) { 863 free(fs->fs_active, M_DEVBUF); 864 fs->fs_active = 0; 865 } 866 UFS_UNLOCK(ump); 867 MNT_ILOCK(mp); 868 mp->mnt_flag = (mp->mnt_flag & MNT_QUOTA) | (flag & ~MNT_QUOTA); 869 MNT_IUNLOCK(mp); 870 NDFREE_PNBUF(&nd); 871 vrele(nd.ni_dvp); 872 if (error == 0) { 873 (void) ffs_syncvnode(vp, MNT_WAIT, 0); 874 VOP_UNLOCK(vp); 875 } else if (VN_IS_DOOMED(vp)) { 876 vput(vp); 877 } else { 878 int rmerr; 879 880 /* Remove snapshot as its creation has failed. */ 881 vput(vp); 882 NDINIT(&nd, DELETE, LOCKPARENT | LOCKLEAF, UIO_SYSSPACE, 883 snapfile); 884 if ((rmerr = namei(&nd)) != 0 || 885 (rmerr = VOP_REMOVE(nd.ni_dvp, nd.ni_vp, &nd.ni_cnd)) != 0) 886 printf("Delete of %s failed with error %d\n", 887 nd.ni_dirp, rmerr); 888 NDFREE_PNBUF(&nd); 889 if (nd.ni_dvp != NULL) 890 vput(nd.ni_dvp); 891 if (nd.ni_vp != NULL) 892 vput(nd.ni_vp); 893 } 894 vn_finished_write(wrtmp); 895 process_deferred_inactive(mp); 896 return (error); 897 } 898 899 /* 900 * Copy a cylinder group map. All the unallocated blocks are marked 901 * BLK_NOCOPY so that the snapshot knows that it need not copy them 902 * if they are later written. If passno is one, then this is a first 903 * pass, so only setting needs to be done. If passno is 2, then this 904 * is a revision to a previous pass which must be undone as the 905 * replacement pass is done. 906 */ 907 static int 908 cgaccount(int cg, 909 struct vnode *vp, 910 struct buf *nbp, 911 int passno) 912 { 913 struct buf *bp, *ibp; 914 struct inode *ip; 915 struct cg *cgp; 916 struct fs *fs; 917 ufs2_daddr_t base, numblks; 918 int error, len, loc, indiroff; 919 920 ip = VTOI(vp); 921 fs = ITOFS(ip); 922 if ((error = ffs_getcg(fs, ITODEVVP(ip), cg, 0, &bp, &cgp)) != 0) 923 return (error); 924 UFS_LOCK(ITOUMP(ip)); 925 ACTIVESET(fs, cg); 926 /* 927 * Recomputation of summary information might not have been performed 928 * at mount time. Sync up summary information for current cylinder 929 * group while data is in memory to ensure that result of background 930 * fsck is slightly more consistent. 931 */ 932 fs->fs_cs(fs, cg) = cgp->cg_cs; 933 UFS_UNLOCK(ITOUMP(ip)); 934 bcopy(bp->b_data, nbp->b_data, fs->fs_cgsize); 935 if (fs->fs_cgsize < fs->fs_bsize) 936 bzero(&nbp->b_data[fs->fs_cgsize], 937 fs->fs_bsize - fs->fs_cgsize); 938 cgp = (struct cg *)nbp->b_data; 939 bqrelse(bp); 940 if (passno == 2) 941 nbp->b_flags |= B_VALIDSUSPWRT; 942 numblks = howmany(fs->fs_size, fs->fs_frag); 943 len = howmany(fs->fs_fpg, fs->fs_frag); 944 base = cgbase(fs, cg) / fs->fs_frag; 945 if (base + len >= numblks) 946 len = numblks - base - 1; 947 loc = 0; 948 if (base < UFS_NDADDR) { 949 for ( ; loc < UFS_NDADDR; loc++) { 950 if (ffs_isblock(fs, cg_blksfree(cgp), loc)) 951 DIP_SET(ip, i_db[loc], BLK_NOCOPY); 952 else if (passno == 2 && DIP(ip, i_db[loc])== BLK_NOCOPY) 953 DIP_SET(ip, i_db[loc], 0); 954 else if (passno == 1 && DIP(ip, i_db[loc])== BLK_NOCOPY) 955 panic("ffs_snapshot: lost direct block"); 956 } 957 } 958 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)(base + loc)), 959 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp); 960 if (error) { 961 goto out; 962 } 963 indiroff = (base + loc - UFS_NDADDR) % NINDIR(fs); 964 for ( ; loc < len; loc++, indiroff++) { 965 if (indiroff >= NINDIR(fs)) { 966 if (passno == 2) 967 ibp->b_flags |= B_VALIDSUSPWRT; 968 bawrite(ibp); 969 error = UFS_BALLOC(vp, 970 lblktosize(fs, (off_t)(base + loc)), 971 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp); 972 if (error) { 973 goto out; 974 } 975 indiroff = 0; 976 } 977 if (I_IS_UFS1(ip)) { 978 if (ffs_isblock(fs, cg_blksfree(cgp), loc)) 979 ((ufs1_daddr_t *)(ibp->b_data))[indiroff] = 980 BLK_NOCOPY; 981 else if (passno == 2 && ((ufs1_daddr_t *)(ibp->b_data)) 982 [indiroff] == BLK_NOCOPY) 983 ((ufs1_daddr_t *)(ibp->b_data))[indiroff] = 0; 984 else if (passno == 1 && ((ufs1_daddr_t *)(ibp->b_data)) 985 [indiroff] == BLK_NOCOPY) 986 panic("ffs_snapshot: lost indirect block"); 987 continue; 988 } 989 if (ffs_isblock(fs, cg_blksfree(cgp), loc)) 990 ((ufs2_daddr_t *)(ibp->b_data))[indiroff] = BLK_NOCOPY; 991 else if (passno == 2 && 992 ((ufs2_daddr_t *)(ibp->b_data)) [indiroff] == BLK_NOCOPY) 993 ((ufs2_daddr_t *)(ibp->b_data))[indiroff] = 0; 994 else if (passno == 1 && 995 ((ufs2_daddr_t *)(ibp->b_data)) [indiroff] == BLK_NOCOPY) 996 panic("ffs_snapshot: lost indirect block"); 997 } 998 if (passno == 2) 999 ibp->b_flags |= B_VALIDSUSPWRT; 1000 bdwrite(ibp); 1001 out: 1002 /* 1003 * We have to calculate the crc32c here rather than just setting the 1004 * BX_CYLGRP b_xflags because the allocation of the block for the 1005 * the cylinder group map will always be a full size block (fs_bsize) 1006 * even though the cylinder group may be smaller (fs_cgsize). The 1007 * crc32c must be computed only over fs_cgsize whereas the BX_CYLGRP 1008 * flag causes it to be computed over the size of the buffer. 1009 */ 1010 if ((fs->fs_metackhash & CK_CYLGRP) != 0) { 1011 ((struct cg *)nbp->b_data)->cg_ckhash = 0; 1012 ((struct cg *)nbp->b_data)->cg_ckhash = 1013 calculate_crc32c(~0L, nbp->b_data, fs->fs_cgsize); 1014 } 1015 return (error); 1016 } 1017 1018 /* 1019 * Before expunging a snapshot inode, note all the 1020 * blocks that it claims with BLK_SNAP so that fsck will 1021 * be able to account for those blocks properly and so 1022 * that this snapshot knows that it need not copy them 1023 * if the other snapshot holding them is freed. This code 1024 * is reproduced once each for UFS1 and UFS2. 1025 */ 1026 static int 1027 expunge_ufs1(struct vnode *snapvp, 1028 struct inode *cancelip, 1029 struct fs *fs, 1030 int (*acctfunc)(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *, 1031 struct fs *, ufs_lbn_t, int), 1032 int expungetype, 1033 int clearmode) 1034 { 1035 int i, error, indiroff; 1036 ufs_lbn_t lbn, rlbn; 1037 ufs2_daddr_t len, blkno, numblks, blksperindir; 1038 struct ufs1_dinode *dip; 1039 struct thread *td = curthread; 1040 struct buf *bp; 1041 1042 /* 1043 * Prepare to expunge the inode. If its inode block has not 1044 * yet been copied, then allocate and fill the copy. 1045 */ 1046 lbn = fragstoblks(fs, ino_to_fsba(fs, cancelip->i_number)); 1047 blkno = 0; 1048 if (lbn < UFS_NDADDR) { 1049 blkno = VTOI(snapvp)->i_din1->di_db[lbn]; 1050 } else { 1051 if (DOINGSOFTDEP(snapvp)) 1052 softdep_prealloc(snapvp, MNT_WAIT); 1053 td->td_pflags |= TDP_COWINPROGRESS; 1054 error = ffs_balloc_ufs1(snapvp, lblktosize(fs, (off_t)lbn), 1055 fs->fs_bsize, KERNCRED, BA_METAONLY, &bp); 1056 td->td_pflags &= ~TDP_COWINPROGRESS; 1057 if (error) 1058 return (error); 1059 indiroff = (lbn - UFS_NDADDR) % NINDIR(fs); 1060 blkno = ((ufs1_daddr_t *)(bp->b_data))[indiroff]; 1061 bqrelse(bp); 1062 } 1063 if (blkno != 0) { 1064 if ((error = bread(snapvp, lbn, fs->fs_bsize, KERNCRED, &bp))) 1065 return (error); 1066 } else { 1067 error = ffs_balloc_ufs1(snapvp, lblktosize(fs, (off_t)lbn), 1068 fs->fs_bsize, KERNCRED, 0, &bp); 1069 if (error) 1070 return (error); 1071 if ((error = readblock(snapvp, bp, lbn)) != 0) 1072 return (error); 1073 } 1074 /* 1075 * Set a snapshot inode to be a zero length file, regular files 1076 * or unlinked snapshots to be completely unallocated. 1077 */ 1078 dip = (struct ufs1_dinode *)bp->b_data + 1079 ino_to_fsbo(fs, cancelip->i_number); 1080 if (clearmode || cancelip->i_effnlink == 0) 1081 dip->di_mode = 0; 1082 dip->di_size = 0; 1083 dip->di_blocks = 0; 1084 dip->di_flags &= ~SF_SNAPSHOT; 1085 bzero(dip->di_db, UFS_NDADDR * sizeof(ufs1_daddr_t)); 1086 bzero(dip->di_ib, UFS_NIADDR * sizeof(ufs1_daddr_t)); 1087 bdwrite(bp); 1088 /* 1089 * Now go through and expunge all the blocks in the file 1090 * using the function requested. 1091 */ 1092 numblks = howmany(cancelip->i_size, fs->fs_bsize); 1093 if ((error = (*acctfunc)(snapvp, &cancelip->i_din1->di_db[0], 1094 &cancelip->i_din1->di_db[UFS_NDADDR], fs, 0, expungetype))) 1095 return (error); 1096 if ((error = (*acctfunc)(snapvp, &cancelip->i_din1->di_ib[0], 1097 &cancelip->i_din1->di_ib[UFS_NIADDR], fs, -1, expungetype))) 1098 return (error); 1099 blksperindir = 1; 1100 lbn = -UFS_NDADDR; 1101 len = numblks - UFS_NDADDR; 1102 rlbn = UFS_NDADDR; 1103 for (i = 0; len > 0 && i < UFS_NIADDR; i++) { 1104 error = indiracct_ufs1(snapvp, ITOV(cancelip), i, 1105 cancelip->i_din1->di_ib[i], lbn, rlbn, len, 1106 blksperindir, fs, acctfunc, expungetype); 1107 if (error) 1108 return (error); 1109 blksperindir *= NINDIR(fs); 1110 lbn -= blksperindir + 1; 1111 len -= blksperindir; 1112 rlbn += blksperindir; 1113 } 1114 return (0); 1115 } 1116 1117 /* 1118 * Descend an indirect block chain for vnode cancelvp accounting for all 1119 * its indirect blocks in snapvp. 1120 */ 1121 static int 1122 indiracct_ufs1(struct vnode *snapvp, 1123 struct vnode *cancelvp, 1124 int level, 1125 ufs1_daddr_t blkno, 1126 ufs_lbn_t lbn, 1127 ufs_lbn_t rlbn, 1128 ufs_lbn_t remblks, 1129 ufs_lbn_t blksperindir, 1130 struct fs *fs, 1131 int (*acctfunc)(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *, 1132 struct fs *, ufs_lbn_t, int), 1133 int expungetype) 1134 { 1135 int error, num, i; 1136 ufs_lbn_t subblksperindir; 1137 struct indir indirs[UFS_NIADDR + 2]; 1138 ufs1_daddr_t last, *bap; 1139 struct buf *bp; 1140 1141 if (blkno == 0) { 1142 if (expungetype == BLK_NOCOPY) 1143 return (0); 1144 panic("indiracct_ufs1: missing indir"); 1145 } 1146 if ((error = ufs_getlbns(cancelvp, rlbn, indirs, &num)) != 0) 1147 return (error); 1148 if (lbn != indirs[num - 1 - level].in_lbn || num < 2) 1149 panic("indiracct_ufs1: botched params"); 1150 /* 1151 * We have to expand bread here since it will deadlock looking 1152 * up the block number for any blocks that are not in the cache. 1153 */ 1154 bp = getblk(cancelvp, lbn, fs->fs_bsize, 0, 0, 0); 1155 bp->b_blkno = fsbtodb(fs, blkno); 1156 if ((bp->b_flags & (B_DONE | B_DELWRI)) == 0 && 1157 (error = readblock(cancelvp, bp, fragstoblks(fs, blkno)))) { 1158 brelse(bp); 1159 return (error); 1160 } 1161 /* 1162 * Account for the block pointers in this indirect block. 1163 */ 1164 last = howmany(remblks, blksperindir); 1165 if (last > NINDIR(fs)) 1166 last = NINDIR(fs); 1167 bap = malloc(fs->fs_bsize, M_DEVBUF, M_WAITOK); 1168 bcopy(bp->b_data, (caddr_t)bap, fs->fs_bsize); 1169 bqrelse(bp); 1170 error = (*acctfunc)(snapvp, &bap[0], &bap[last], fs, 1171 level == 0 ? rlbn : -1, expungetype); 1172 if (error || level == 0) 1173 goto out; 1174 /* 1175 * Account for the block pointers in each of the indirect blocks 1176 * in the levels below us. 1177 */ 1178 subblksperindir = blksperindir / NINDIR(fs); 1179 for (lbn++, level--, i = 0; i < last; i++) { 1180 error = indiracct_ufs1(snapvp, cancelvp, level, bap[i], lbn, 1181 rlbn, remblks, subblksperindir, fs, acctfunc, expungetype); 1182 if (error) 1183 goto out; 1184 rlbn += blksperindir; 1185 lbn -= blksperindir; 1186 remblks -= blksperindir; 1187 } 1188 out: 1189 free(bap, M_DEVBUF); 1190 return (error); 1191 } 1192 1193 /* 1194 * Do both snap accounting and map accounting. 1195 */ 1196 static int 1197 fullacct_ufs1(struct vnode *vp, 1198 ufs1_daddr_t *oldblkp, 1199 ufs1_daddr_t *lastblkp, 1200 struct fs *fs, 1201 ufs_lbn_t lblkno, 1202 int exptype) /* BLK_SNAP or BLK_NOCOPY */ 1203 { 1204 int error; 1205 1206 if ((error = snapacct_ufs1(vp, oldblkp, lastblkp, fs, lblkno, exptype))) 1207 return (error); 1208 return (mapacct_ufs1(vp, oldblkp, lastblkp, fs, lblkno, exptype)); 1209 } 1210 1211 /* 1212 * Identify a set of blocks allocated in a snapshot inode. 1213 */ 1214 static int 1215 snapacct_ufs1(struct vnode *vp, 1216 ufs1_daddr_t *oldblkp, 1217 ufs1_daddr_t *lastblkp, 1218 struct fs *fs, 1219 ufs_lbn_t lblkno, 1220 int expungetype) /* BLK_SNAP or BLK_NOCOPY */ 1221 { 1222 struct inode *ip = VTOI(vp); 1223 ufs1_daddr_t blkno, *blkp; 1224 ufs_lbn_t lbn; 1225 struct buf *ibp; 1226 int error; 1227 1228 for ( ; oldblkp < lastblkp; oldblkp++) { 1229 blkno = *oldblkp; 1230 if (blkno == 0 || blkno == BLK_NOCOPY || blkno == BLK_SNAP) 1231 continue; 1232 lbn = fragstoblks(fs, blkno); 1233 if (lbn < UFS_NDADDR) { 1234 blkp = &ip->i_din1->di_db[lbn]; 1235 UFS_INODE_SET_FLAG(ip, IN_CHANGE | IN_UPDATE); 1236 } else { 1237 error = ffs_balloc_ufs1(vp, lblktosize(fs, (off_t)lbn), 1238 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp); 1239 if (error) 1240 return (error); 1241 blkp = &((ufs1_daddr_t *)(ibp->b_data)) 1242 [(lbn - UFS_NDADDR) % NINDIR(fs)]; 1243 } 1244 /* 1245 * If we are expunging a snapshot vnode and we 1246 * find a block marked BLK_NOCOPY, then it is 1247 * one that has been allocated to this snapshot after 1248 * we took our current snapshot and can be ignored. 1249 */ 1250 if (expungetype == BLK_SNAP && *blkp == BLK_NOCOPY) { 1251 if (lbn >= UFS_NDADDR) 1252 brelse(ibp); 1253 } else { 1254 if (*blkp != 0) 1255 panic("snapacct_ufs1: bad block"); 1256 *blkp = expungetype; 1257 if (lbn >= UFS_NDADDR) 1258 bdwrite(ibp); 1259 } 1260 } 1261 return (0); 1262 } 1263 1264 /* 1265 * Account for a set of blocks allocated in a snapshot inode. 1266 */ 1267 static int 1268 mapacct_ufs1(struct vnode *vp, 1269 ufs1_daddr_t *oldblkp, 1270 ufs1_daddr_t *lastblkp, 1271 struct fs *fs, 1272 ufs_lbn_t lblkno, 1273 int expungetype) 1274 { 1275 ufs1_daddr_t blkno; 1276 struct inode *ip; 1277 ino_t inum; 1278 int acctit; 1279 1280 ip = VTOI(vp); 1281 inum = ip->i_number; 1282 if (lblkno == -1) 1283 acctit = 0; 1284 else 1285 acctit = 1; 1286 for ( ; oldblkp < lastblkp; oldblkp++, lblkno++) { 1287 blkno = *oldblkp; 1288 if (blkno == 0 || blkno == BLK_NOCOPY) 1289 continue; 1290 if (acctit && expungetype == BLK_SNAP && blkno != BLK_SNAP) 1291 *ip->i_snapblklist++ = lblkno; 1292 if (blkno == BLK_SNAP) 1293 blkno = blkstofrags(fs, lblkno); 1294 ffs_blkfree(ITOUMP(ip), fs, vp, blkno, fs->fs_bsize, inum, 1295 vp->v_type, NULL, SINGLETON_KEY); 1296 } 1297 return (0); 1298 } 1299 1300 /* 1301 * Before expunging a snapshot inode, note all the 1302 * blocks that it claims with BLK_SNAP so that fsck will 1303 * be able to account for those blocks properly and so 1304 * that this snapshot knows that it need not copy them 1305 * if the other snapshot holding them is freed. This code 1306 * is reproduced once each for UFS1 and UFS2. 1307 */ 1308 static int 1309 expunge_ufs2(struct vnode *snapvp, 1310 struct inode *cancelip, 1311 struct fs *fs, 1312 int (*acctfunc)(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *, 1313 struct fs *, ufs_lbn_t, int), 1314 int expungetype, 1315 int clearmode) 1316 { 1317 int i, error, indiroff; 1318 ufs_lbn_t lbn, rlbn; 1319 ufs2_daddr_t len, blkno, numblks, blksperindir; 1320 struct ufs2_dinode *dip; 1321 struct thread *td = curthread; 1322 struct buf *bp; 1323 1324 /* 1325 * Prepare to expunge the inode. If its inode block has not 1326 * yet been copied, then allocate and fill the copy. 1327 */ 1328 lbn = fragstoblks(fs, ino_to_fsba(fs, cancelip->i_number)); 1329 blkno = 0; 1330 if (lbn < UFS_NDADDR) { 1331 blkno = VTOI(snapvp)->i_din2->di_db[lbn]; 1332 } else { 1333 if (DOINGSOFTDEP(snapvp)) 1334 softdep_prealloc(snapvp, MNT_WAIT); 1335 td->td_pflags |= TDP_COWINPROGRESS; 1336 error = ffs_balloc_ufs2(snapvp, lblktosize(fs, (off_t)lbn), 1337 fs->fs_bsize, KERNCRED, BA_METAONLY, &bp); 1338 td->td_pflags &= ~TDP_COWINPROGRESS; 1339 if (error) 1340 return (error); 1341 indiroff = (lbn - UFS_NDADDR) % NINDIR(fs); 1342 blkno = ((ufs2_daddr_t *)(bp->b_data))[indiroff]; 1343 bqrelse(bp); 1344 } 1345 if (blkno != 0) { 1346 if ((error = bread(snapvp, lbn, fs->fs_bsize, KERNCRED, &bp))) 1347 return (error); 1348 } else { 1349 error = ffs_balloc_ufs2(snapvp, lblktosize(fs, (off_t)lbn), 1350 fs->fs_bsize, KERNCRED, 0, &bp); 1351 if (error) 1352 return (error); 1353 if ((error = readblock(snapvp, bp, lbn)) != 0) 1354 return (error); 1355 } 1356 /* 1357 * Set a snapshot inode to be a zero length file, regular files 1358 * to be completely unallocated. 1359 */ 1360 dip = (struct ufs2_dinode *)bp->b_data + 1361 ino_to_fsbo(fs, cancelip->i_number); 1362 dip->di_size = 0; 1363 dip->di_blocks = 0; 1364 dip->di_flags &= ~SF_SNAPSHOT; 1365 bzero(dip->di_db, UFS_NDADDR * sizeof(ufs2_daddr_t)); 1366 bzero(dip->di_ib, UFS_NIADDR * sizeof(ufs2_daddr_t)); 1367 if (clearmode || cancelip->i_effnlink == 0) 1368 dip->di_mode = 0; 1369 else 1370 ffs_update_dinode_ckhash(fs, dip); 1371 bdwrite(bp); 1372 /* 1373 * Now go through and expunge all the blocks in the file 1374 * using the function requested. 1375 */ 1376 numblks = howmany(cancelip->i_size, fs->fs_bsize); 1377 if ((error = (*acctfunc)(snapvp, &cancelip->i_din2->di_db[0], 1378 &cancelip->i_din2->di_db[UFS_NDADDR], fs, 0, expungetype))) 1379 return (error); 1380 if ((error = (*acctfunc)(snapvp, &cancelip->i_din2->di_ib[0], 1381 &cancelip->i_din2->di_ib[UFS_NIADDR], fs, -1, expungetype))) 1382 return (error); 1383 blksperindir = 1; 1384 lbn = -UFS_NDADDR; 1385 len = numblks - UFS_NDADDR; 1386 rlbn = UFS_NDADDR; 1387 for (i = 0; len > 0 && i < UFS_NIADDR; i++) { 1388 error = indiracct_ufs2(snapvp, ITOV(cancelip), i, 1389 cancelip->i_din2->di_ib[i], lbn, rlbn, len, 1390 blksperindir, fs, acctfunc, expungetype); 1391 if (error) 1392 return (error); 1393 blksperindir *= NINDIR(fs); 1394 lbn -= blksperindir + 1; 1395 len -= blksperindir; 1396 rlbn += blksperindir; 1397 } 1398 return (0); 1399 } 1400 1401 /* 1402 * Descend an indirect block chain for vnode cancelvp accounting for all 1403 * its indirect blocks in snapvp. 1404 */ 1405 static int 1406 indiracct_ufs2(struct vnode *snapvp, 1407 struct vnode *cancelvp, 1408 int level, 1409 ufs2_daddr_t blkno, 1410 ufs_lbn_t lbn, 1411 ufs_lbn_t rlbn, 1412 ufs_lbn_t remblks, 1413 ufs_lbn_t blksperindir, 1414 struct fs *fs, 1415 int (*acctfunc)(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *, 1416 struct fs *, ufs_lbn_t, int), 1417 int expungetype) 1418 { 1419 int error, num, i; 1420 ufs_lbn_t subblksperindir; 1421 struct indir indirs[UFS_NIADDR + 2]; 1422 ufs2_daddr_t last, *bap; 1423 struct buf *bp; 1424 1425 if (blkno == 0) { 1426 if (expungetype == BLK_NOCOPY) 1427 return (0); 1428 panic("indiracct_ufs2: missing indir"); 1429 } 1430 if ((error = ufs_getlbns(cancelvp, rlbn, indirs, &num)) != 0) 1431 return (error); 1432 if (lbn != indirs[num - 1 - level].in_lbn || num < 2) 1433 panic("indiracct_ufs2: botched params"); 1434 /* 1435 * We have to expand bread here since it will deadlock looking 1436 * up the block number for any blocks that are not in the cache. 1437 */ 1438 bp = getblk(cancelvp, lbn, fs->fs_bsize, 0, 0, 0); 1439 bp->b_blkno = fsbtodb(fs, blkno); 1440 if ((bp->b_flags & B_CACHE) == 0 && 1441 (error = readblock(cancelvp, bp, fragstoblks(fs, blkno)))) { 1442 brelse(bp); 1443 return (error); 1444 } 1445 /* 1446 * Account for the block pointers in this indirect block. 1447 */ 1448 last = howmany(remblks, blksperindir); 1449 if (last > NINDIR(fs)) 1450 last = NINDIR(fs); 1451 bap = malloc(fs->fs_bsize, M_DEVBUF, M_WAITOK); 1452 bcopy(bp->b_data, (caddr_t)bap, fs->fs_bsize); 1453 bqrelse(bp); 1454 error = (*acctfunc)(snapvp, &bap[0], &bap[last], fs, 1455 level == 0 ? rlbn : -1, expungetype); 1456 if (error || level == 0) 1457 goto out; 1458 /* 1459 * Account for the block pointers in each of the indirect blocks 1460 * in the levels below us. 1461 */ 1462 subblksperindir = blksperindir / NINDIR(fs); 1463 for (lbn++, level--, i = 0; i < last; i++) { 1464 error = indiracct_ufs2(snapvp, cancelvp, level, bap[i], lbn, 1465 rlbn, remblks, subblksperindir, fs, acctfunc, expungetype); 1466 if (error) 1467 goto out; 1468 rlbn += blksperindir; 1469 lbn -= blksperindir; 1470 remblks -= blksperindir; 1471 } 1472 out: 1473 free(bap, M_DEVBUF); 1474 return (error); 1475 } 1476 1477 /* 1478 * Do both snap accounting and map accounting. 1479 */ 1480 static int 1481 fullacct_ufs2(struct vnode *vp, 1482 ufs2_daddr_t *oldblkp, 1483 ufs2_daddr_t *lastblkp, 1484 struct fs *fs, 1485 ufs_lbn_t lblkno, 1486 int exptype) /* BLK_SNAP or BLK_NOCOPY */ 1487 { 1488 int error; 1489 1490 if ((error = snapacct_ufs2(vp, oldblkp, lastblkp, fs, lblkno, exptype))) 1491 return (error); 1492 return (mapacct_ufs2(vp, oldblkp, lastblkp, fs, lblkno, exptype)); 1493 } 1494 1495 /* 1496 * Identify a set of blocks allocated in a snapshot inode. 1497 */ 1498 static int 1499 snapacct_ufs2(struct vnode *vp, 1500 ufs2_daddr_t *oldblkp, 1501 ufs2_daddr_t *lastblkp, 1502 struct fs *fs, 1503 ufs_lbn_t lblkno, 1504 int expungetype) /* BLK_SNAP or BLK_NOCOPY */ 1505 { 1506 struct inode *ip = VTOI(vp); 1507 ufs2_daddr_t blkno, *blkp; 1508 ufs_lbn_t lbn; 1509 struct buf *ibp; 1510 int error; 1511 1512 for ( ; oldblkp < lastblkp; oldblkp++) { 1513 blkno = *oldblkp; 1514 if (blkno == 0 || blkno == BLK_NOCOPY || blkno == BLK_SNAP) 1515 continue; 1516 lbn = fragstoblks(fs, blkno); 1517 if (lbn < UFS_NDADDR) { 1518 blkp = &ip->i_din2->di_db[lbn]; 1519 UFS_INODE_SET_FLAG(ip, IN_CHANGE | IN_UPDATE); 1520 } else { 1521 error = ffs_balloc_ufs2(vp, lblktosize(fs, (off_t)lbn), 1522 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp); 1523 if (error) 1524 return (error); 1525 blkp = &((ufs2_daddr_t *)(ibp->b_data)) 1526 [(lbn - UFS_NDADDR) % NINDIR(fs)]; 1527 } 1528 /* 1529 * If we are expunging a snapshot vnode and we 1530 * find a block marked BLK_NOCOPY, then it is 1531 * one that has been allocated to this snapshot after 1532 * we took our current snapshot and can be ignored. 1533 */ 1534 if (expungetype == BLK_SNAP && *blkp == BLK_NOCOPY) { 1535 if (lbn >= UFS_NDADDR) 1536 brelse(ibp); 1537 } else { 1538 if (*blkp != 0) 1539 panic("snapacct_ufs2: bad block"); 1540 *blkp = expungetype; 1541 if (lbn >= UFS_NDADDR) 1542 bdwrite(ibp); 1543 } 1544 } 1545 return (0); 1546 } 1547 1548 /* 1549 * Account for a set of blocks allocated in a snapshot inode. 1550 */ 1551 static int 1552 mapacct_ufs2(struct vnode *vp, 1553 ufs2_daddr_t *oldblkp, 1554 ufs2_daddr_t *lastblkp, 1555 struct fs *fs, 1556 ufs_lbn_t lblkno, 1557 int expungetype) 1558 { 1559 ufs2_daddr_t blkno; 1560 struct inode *ip; 1561 ino_t inum; 1562 int acctit; 1563 1564 ip = VTOI(vp); 1565 inum = ip->i_number; 1566 if (lblkno == -1) 1567 acctit = 0; 1568 else 1569 acctit = 1; 1570 for ( ; oldblkp < lastblkp; oldblkp++, lblkno++) { 1571 blkno = *oldblkp; 1572 if (blkno == 0 || blkno == BLK_NOCOPY) 1573 continue; 1574 if (acctit && expungetype == BLK_SNAP && blkno != BLK_SNAP && 1575 lblkno >= UFS_NDADDR) 1576 *ip->i_snapblklist++ = lblkno; 1577 if (blkno == BLK_SNAP) 1578 blkno = blkstofrags(fs, lblkno); 1579 ffs_blkfree(ITOUMP(ip), fs, vp, blkno, fs->fs_bsize, inum, 1580 vp->v_type, NULL, SINGLETON_KEY); 1581 } 1582 return (0); 1583 } 1584 1585 /* 1586 * Decrement extra reference on snapshot when last name is removed. 1587 * It will not be freed until the last open reference goes away. 1588 */ 1589 void 1590 ffs_snapgone(struct inode *ip) 1591 { 1592 struct inode *xp; 1593 struct fs *fs; 1594 int snaploc; 1595 struct snapdata *sn; 1596 struct ufsmount *ump; 1597 1598 /* 1599 * Find snapshot in incore list. 1600 */ 1601 xp = NULL; 1602 sn = ITODEVVP(ip)->v_rdev->si_snapdata; 1603 if (sn != NULL) 1604 TAILQ_FOREACH(xp, &sn->sn_head, i_nextsnap) 1605 if (xp == ip) 1606 break; 1607 if (xp != NULL) 1608 vrele(ITOV(ip)); 1609 #ifdef DIAGNOSTIC 1610 else if (snapdebug) 1611 printf("ffs_snapgone: lost snapshot vnode %ju\n", 1612 (uintmax_t)ip->i_number); 1613 #endif 1614 /* 1615 * Delete snapshot inode from superblock. Keep list dense. 1616 */ 1617 ump = ITOUMP(ip); 1618 fs = ump->um_fs; 1619 UFS_LOCK(ump); 1620 for (snaploc = 0; snaploc < FSMAXSNAP; snaploc++) 1621 if (fs->fs_snapinum[snaploc] == ip->i_number) 1622 break; 1623 if (snaploc < FSMAXSNAP) { 1624 for (snaploc++; snaploc < FSMAXSNAP; snaploc++) { 1625 if (fs->fs_snapinum[snaploc] == 0) 1626 break; 1627 fs->fs_snapinum[snaploc - 1] = fs->fs_snapinum[snaploc]; 1628 } 1629 fs->fs_snapinum[snaploc - 1] = 0; 1630 } 1631 UFS_UNLOCK(ump); 1632 } 1633 1634 /* 1635 * Prepare a snapshot file for being removed. 1636 */ 1637 void 1638 ffs_snapremove(struct vnode *vp) 1639 { 1640 struct inode *ip; 1641 struct vnode *devvp; 1642 struct buf *ibp; 1643 struct fs *fs; 1644 ufs2_daddr_t numblks, blkno, dblk; 1645 int error, last, loc; 1646 struct snapdata *sn; 1647 1648 ip = VTOI(vp); 1649 fs = ITOFS(ip); 1650 devvp = ITODEVVP(ip); 1651 /* 1652 * If active, delete from incore list (this snapshot may 1653 * already have been in the process of being deleted, so 1654 * would not have been active). 1655 * 1656 * Clear copy-on-write flag if last snapshot. 1657 */ 1658 VI_LOCK(devvp); 1659 if (ip->i_nextsnap.tqe_prev != 0) { 1660 sn = devvp->v_rdev->si_snapdata; 1661 TAILQ_REMOVE(&sn->sn_head, ip, i_nextsnap); 1662 ip->i_nextsnap.tqe_prev = 0; 1663 revert_snaplock(vp, devvp, sn); 1664 try_free_snapdata(devvp); 1665 } 1666 VI_UNLOCK(devvp); 1667 /* 1668 * Clear all BLK_NOCOPY fields. Pass any block claims to other 1669 * snapshots that want them (see ffs_snapblkfree below). 1670 */ 1671 for (blkno = 1; blkno < UFS_NDADDR; blkno++) { 1672 dblk = DIP(ip, i_db[blkno]); 1673 if (dblk == 0) 1674 continue; 1675 if (dblk == BLK_NOCOPY || dblk == BLK_SNAP) 1676 DIP_SET(ip, i_db[blkno], 0); 1677 else if ((dblk == blkstofrags(fs, blkno) && 1678 ffs_snapblkfree(fs, ITODEVVP(ip), dblk, fs->fs_bsize, 1679 ip->i_number, vp->v_type, NULL))) { 1680 DIP_SET(ip, i_blocks, DIP(ip, i_blocks) - 1681 btodb(fs->fs_bsize)); 1682 DIP_SET(ip, i_db[blkno], 0); 1683 } 1684 } 1685 numblks = howmany(ip->i_size, fs->fs_bsize); 1686 for (blkno = UFS_NDADDR; blkno < numblks; blkno += NINDIR(fs)) { 1687 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)blkno), 1688 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp); 1689 if (error) 1690 continue; 1691 if (fs->fs_size - blkno > NINDIR(fs)) 1692 last = NINDIR(fs); 1693 else 1694 last = fs->fs_size - blkno; 1695 for (loc = 0; loc < last; loc++) { 1696 if (I_IS_UFS1(ip)) { 1697 dblk = ((ufs1_daddr_t *)(ibp->b_data))[loc]; 1698 if (dblk == 0) 1699 continue; 1700 if (dblk == BLK_NOCOPY || dblk == BLK_SNAP) 1701 ((ufs1_daddr_t *)(ibp->b_data))[loc]= 0; 1702 else if ((dblk == blkstofrags(fs, blkno) && 1703 ffs_snapblkfree(fs, ITODEVVP(ip), dblk, 1704 fs->fs_bsize, ip->i_number, vp->v_type, 1705 NULL))) { 1706 ip->i_din1->di_blocks -= 1707 btodb(fs->fs_bsize); 1708 ((ufs1_daddr_t *)(ibp->b_data))[loc]= 0; 1709 } 1710 continue; 1711 } 1712 dblk = ((ufs2_daddr_t *)(ibp->b_data))[loc]; 1713 if (dblk == 0) 1714 continue; 1715 if (dblk == BLK_NOCOPY || dblk == BLK_SNAP) 1716 ((ufs2_daddr_t *)(ibp->b_data))[loc] = 0; 1717 else if ((dblk == blkstofrags(fs, blkno) && 1718 ffs_snapblkfree(fs, ITODEVVP(ip), dblk, 1719 fs->fs_bsize, ip->i_number, vp->v_type, NULL))) { 1720 ip->i_din2->di_blocks -= btodb(fs->fs_bsize); 1721 ((ufs2_daddr_t *)(ibp->b_data))[loc] = 0; 1722 } 1723 } 1724 bawrite(ibp); 1725 } 1726 /* 1727 * Clear snapshot flag and drop reference. 1728 */ 1729 ip->i_flags &= ~SF_SNAPSHOT; 1730 DIP_SET(ip, i_flags, ip->i_flags); 1731 UFS_INODE_SET_FLAG(ip, IN_CHANGE | IN_UPDATE); 1732 /* 1733 * The dirtied indirects must be written out before 1734 * softdep_setup_freeblocks() is called. Otherwise indir_trunc() 1735 * may find indirect pointers using the magic BLK_* values. 1736 */ 1737 if (DOINGSOFTDEP(vp)) 1738 ffs_syncvnode(vp, MNT_WAIT, 0); 1739 #ifdef QUOTA 1740 /* 1741 * Reenable disk quotas for ex-snapshot file. 1742 */ 1743 if (!getinoquota(ip)) 1744 (void) chkdq(ip, DIP(ip, i_blocks), KERNCRED, FORCE); 1745 #endif 1746 } 1747 1748 /* 1749 * Notification that a block is being freed. Return zero if the free 1750 * should be allowed to proceed. Return non-zero if the snapshot file 1751 * wants to claim the block. The block will be claimed if it is an 1752 * uncopied part of one of the snapshots. It will be freed if it is 1753 * either a BLK_NOCOPY or has already been copied in all of the snapshots. 1754 * If a fragment is being freed, then all snapshots that care about 1755 * it must make a copy since a snapshot file can only claim full sized 1756 * blocks. Note that if more than one snapshot file maps the block, 1757 * we can pick one at random to claim it. Since none of the snapshots 1758 * can change, we are assurred that they will all see the same unmodified 1759 * image. When deleting a snapshot file (see ffs_snapremove above), we 1760 * must push any of these claimed blocks to one of the other snapshots 1761 * that maps it. These claimed blocks are easily identified as they will 1762 * have a block number equal to their logical block number within the 1763 * snapshot. A copied block can never have this property because they 1764 * must always have been allocated from a BLK_NOCOPY location. 1765 */ 1766 int 1767 ffs_snapblkfree(struct fs *fs, 1768 struct vnode *devvp, 1769 ufs2_daddr_t bno, 1770 long size, 1771 ino_t inum, 1772 __enum_uint8(vtype) vtype, 1773 struct workhead *wkhd) 1774 { 1775 struct buf *ibp, *cbp, *savedcbp = NULL; 1776 struct thread *td = curthread; 1777 struct inode *ip; 1778 struct vnode *vp = NULL; 1779 ufs_lbn_t lbn; 1780 ufs2_daddr_t blkno; 1781 int indiroff = 0, error = 0, claimedblk = 0; 1782 struct snapdata *sn; 1783 1784 lbn = fragstoblks(fs, bno); 1785 retry: 1786 VI_LOCK(devvp); 1787 sn = devvp->v_rdev->si_snapdata; 1788 if (sn == NULL) { 1789 VI_UNLOCK(devvp); 1790 return (0); 1791 } 1792 1793 /* 1794 * Use LK_SLEEPFAIL because sn might be freed under us while 1795 * both devvp interlock and snaplk are not owned. 1796 */ 1797 if (lockmgr(&sn->sn_lock, LK_INTERLOCK | LK_EXCLUSIVE | LK_SLEEPFAIL, 1798 VI_MTX(devvp)) != 0) 1799 goto retry; 1800 1801 TAILQ_FOREACH(ip, &sn->sn_head, i_nextsnap) { 1802 vp = ITOV(ip); 1803 if (DOINGSOFTDEP(vp)) 1804 softdep_prealloc(vp, MNT_WAIT); 1805 /* 1806 * Lookup block being written. 1807 */ 1808 if (lbn < UFS_NDADDR) { 1809 blkno = DIP(ip, i_db[lbn]); 1810 } else { 1811 td->td_pflags |= TDP_COWINPROGRESS; 1812 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)lbn), 1813 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp); 1814 td->td_pflags &= ~TDP_COWINPROGRESS; 1815 if (error) 1816 break; 1817 indiroff = (lbn - UFS_NDADDR) % NINDIR(fs); 1818 if (I_IS_UFS1(ip)) 1819 blkno=((ufs1_daddr_t *)(ibp->b_data))[indiroff]; 1820 else 1821 blkno=((ufs2_daddr_t *)(ibp->b_data))[indiroff]; 1822 } 1823 /* 1824 * Check to see if block needs to be copied. 1825 */ 1826 if (blkno == 0) { 1827 /* 1828 * A block that we map is being freed. If it has not 1829 * been claimed yet, we will claim or copy it (below). 1830 */ 1831 claimedblk = 1; 1832 } else if (blkno == BLK_SNAP) { 1833 /* 1834 * No previous snapshot claimed the block, 1835 * so it will be freed and become a BLK_NOCOPY 1836 * (don't care) for us. 1837 */ 1838 if (claimedblk) 1839 panic("snapblkfree: inconsistent block type"); 1840 if (lbn < UFS_NDADDR) { 1841 DIP_SET(ip, i_db[lbn], BLK_NOCOPY); 1842 UFS_INODE_SET_FLAG(ip, IN_CHANGE | IN_UPDATE); 1843 } else if (I_IS_UFS1(ip)) { 1844 ((ufs1_daddr_t *)(ibp->b_data))[indiroff] = 1845 BLK_NOCOPY; 1846 bdwrite(ibp); 1847 } else { 1848 ((ufs2_daddr_t *)(ibp->b_data))[indiroff] = 1849 BLK_NOCOPY; 1850 bdwrite(ibp); 1851 } 1852 continue; 1853 } else /* BLK_NOCOPY or default */ { 1854 /* 1855 * If the snapshot has already copied the block 1856 * (default), or does not care about the block, 1857 * it is not needed. 1858 */ 1859 if (lbn >= UFS_NDADDR) 1860 bqrelse(ibp); 1861 continue; 1862 } 1863 /* 1864 * If this is a full size block, we will just grab it 1865 * and assign it to the snapshot inode. Otherwise we 1866 * will proceed to copy it. See explanation for this 1867 * routine as to why only a single snapshot needs to 1868 * claim this block. 1869 */ 1870 if (size == fs->fs_bsize) { 1871 #ifdef DIAGNOSTIC 1872 if (snapdebug) 1873 printf("%s %ju lbn %jd from inum %ju\n", 1874 "Grabonremove: snapino", 1875 (uintmax_t)ip->i_number, 1876 (intmax_t)lbn, (uintmax_t)inum); 1877 #endif 1878 /* 1879 * If journaling is tracking this write we must add 1880 * the work to the inode or indirect being written. 1881 */ 1882 if (wkhd != NULL) { 1883 if (lbn < UFS_NDADDR) 1884 softdep_inode_append(ip, 1885 curthread->td_ucred, wkhd); 1886 else 1887 softdep_buf_append(ibp, wkhd); 1888 } 1889 if (lbn < UFS_NDADDR) { 1890 DIP_SET(ip, i_db[lbn], bno); 1891 } else if (I_IS_UFS1(ip)) { 1892 ((ufs1_daddr_t *)(ibp->b_data))[indiroff] = bno; 1893 bdwrite(ibp); 1894 } else { 1895 ((ufs2_daddr_t *)(ibp->b_data))[indiroff] = bno; 1896 bdwrite(ibp); 1897 } 1898 DIP_SET(ip, i_blocks, DIP(ip, i_blocks) + btodb(size)); 1899 UFS_INODE_SET_FLAG(ip, IN_CHANGE | IN_UPDATE); 1900 lockmgr(vp->v_vnlock, LK_RELEASE, NULL); 1901 return (1); 1902 } 1903 if (lbn >= UFS_NDADDR) 1904 bqrelse(ibp); 1905 /* 1906 * Allocate the block into which to do the copy. Note that this 1907 * allocation will never require any additional allocations for 1908 * the snapshot inode. 1909 */ 1910 td->td_pflags |= TDP_COWINPROGRESS; 1911 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)lbn), 1912 fs->fs_bsize, KERNCRED, 0, &cbp); 1913 td->td_pflags &= ~TDP_COWINPROGRESS; 1914 if (error) 1915 break; 1916 #ifdef DIAGNOSTIC 1917 if (snapdebug) 1918 printf("%s%ju lbn %jd %s %ju size %ld to blkno %jd\n", 1919 "Copyonremove: snapino ", (uintmax_t)ip->i_number, 1920 (intmax_t)lbn, "for inum", (uintmax_t)inum, size, 1921 (intmax_t)cbp->b_blkno); 1922 #endif 1923 /* 1924 * If we have already read the old block contents, then 1925 * simply copy them to the new block. Note that we need 1926 * to synchronously write snapshots that have not been 1927 * unlinked, and hence will be visible after a crash, 1928 * to ensure their integrity. At a minimum we ensure the 1929 * integrity of the filesystem metadata, but use the 1930 * dopersistence sysctl-setable flag to decide on the 1931 * persistence needed for file content data. 1932 */ 1933 if (savedcbp != NULL) { 1934 bcopy(savedcbp->b_data, cbp->b_data, fs->fs_bsize); 1935 bawrite(cbp); 1936 if ((vtype == VDIR || dopersistence) && 1937 ip->i_effnlink > 0) 1938 (void) ffs_syncvnode(vp, MNT_WAIT, NO_INO_UPDT); 1939 continue; 1940 } 1941 /* 1942 * Otherwise, read the old block contents into the buffer. 1943 */ 1944 if ((error = readblock(vp, cbp, lbn)) != 0) { 1945 bzero(cbp->b_data, fs->fs_bsize); 1946 bawrite(cbp); 1947 if ((vtype == VDIR || dopersistence) && 1948 ip->i_effnlink > 0) 1949 (void) ffs_syncvnode(vp, MNT_WAIT, NO_INO_UPDT); 1950 break; 1951 } 1952 savedcbp = cbp; 1953 } 1954 /* 1955 * Note that we need to synchronously write snapshots that 1956 * have not been unlinked, and hence will be visible after 1957 * a crash, to ensure their integrity. At a minimum we 1958 * ensure the integrity of the filesystem metadata, but 1959 * use the dopersistence sysctl-setable flag to decide on 1960 * the persistence needed for file content data. 1961 */ 1962 if (savedcbp) { 1963 vp = savedcbp->b_vp; 1964 bawrite(savedcbp); 1965 if ((vtype == VDIR || dopersistence) && 1966 VTOI(vp)->i_effnlink > 0) 1967 (void) ffs_syncvnode(vp, MNT_WAIT, NO_INO_UPDT); 1968 } 1969 /* 1970 * If we have been unable to allocate a block in which to do 1971 * the copy, then return non-zero so that the fragment will 1972 * not be freed. Although space will be lost, the snapshot 1973 * will stay consistent. 1974 */ 1975 if (error != 0 && wkhd != NULL) 1976 softdep_freework(wkhd); 1977 lockmgr(&sn->sn_lock, LK_RELEASE, NULL); 1978 return (error); 1979 } 1980 1981 /* 1982 * Associate snapshot files when mounting. 1983 */ 1984 void 1985 ffs_snapshot_mount(struct mount *mp) 1986 { 1987 struct ufsmount *ump = VFSTOUFS(mp); 1988 struct vnode *devvp = ump->um_devvp; 1989 struct fs *fs = ump->um_fs; 1990 struct thread *td = curthread; 1991 struct snapdata *sn; 1992 struct vnode *vp; 1993 struct vnode *lastvp; 1994 struct inode *ip; 1995 struct uio auio; 1996 struct iovec aiov; 1997 void *snapblklist; 1998 char *reason; 1999 daddr_t snaplistsize; 2000 int error, snaploc, loc; 2001 2002 /* 2003 * XXX The following needs to be set before ffs_truncate or 2004 * VOP_READ can be called. 2005 */ 2006 mp->mnt_stat.f_iosize = fs->fs_bsize; 2007 /* 2008 * Process each snapshot listed in the superblock. 2009 */ 2010 vp = NULL; 2011 lastvp = NULL; 2012 sn = NULL; 2013 for (snaploc = 0; snaploc < FSMAXSNAP; snaploc++) { 2014 if (fs->fs_snapinum[snaploc] == 0) 2015 break; 2016 if ((error = ffs_vget(mp, fs->fs_snapinum[snaploc], 2017 LK_EXCLUSIVE, &vp)) != 0){ 2018 printf("ffs_snapshot_mount: vget failed %d\n", error); 2019 continue; 2020 } 2021 ip = VTOI(vp); 2022 if (vp->v_type != VREG) { 2023 reason = "non-file snapshot"; 2024 } else if (!IS_SNAPSHOT(ip)) { 2025 reason = "non-snapshot"; 2026 } else if (ip->i_size == 2027 lblktosize(fs, howmany(fs->fs_size, fs->fs_frag))) { 2028 reason = "old format snapshot"; 2029 (void)ffs_truncate(vp, (off_t)0, 0, NOCRED); 2030 (void)ffs_syncvnode(vp, MNT_WAIT, 0); 2031 } else { 2032 reason = NULL; 2033 } 2034 if (reason != NULL) { 2035 printf("ffs_snapshot_mount: %s inode %d\n", 2036 reason, fs->fs_snapinum[snaploc]); 2037 vput(vp); 2038 vp = NULL; 2039 for (loc = snaploc + 1; loc < FSMAXSNAP; loc++) { 2040 if (fs->fs_snapinum[loc] == 0) 2041 break; 2042 fs->fs_snapinum[loc - 1] = fs->fs_snapinum[loc]; 2043 } 2044 fs->fs_snapinum[loc - 1] = 0; 2045 snaploc--; 2046 continue; 2047 } 2048 /* 2049 * Acquire a lock on the snapdata structure, creating it if 2050 * necessary. 2051 */ 2052 sn = ffs_snapdata_acquire(devvp); 2053 /* 2054 * Change vnode to use shared snapshot lock instead of the 2055 * original private lock. 2056 */ 2057 vp->v_vnlock = &sn->sn_lock; 2058 lockmgr(&vp->v_lock, LK_RELEASE, NULL); 2059 /* 2060 * Link it onto the active snapshot list. 2061 */ 2062 VI_LOCK(devvp); 2063 if (ip->i_nextsnap.tqe_prev != 0) 2064 panic("ffs_snapshot_mount: %ju already on list", 2065 (uintmax_t)ip->i_number); 2066 else 2067 TAILQ_INSERT_TAIL(&sn->sn_head, ip, i_nextsnap); 2068 vp->v_vflag |= VV_SYSTEM; 2069 VI_UNLOCK(devvp); 2070 VOP_UNLOCK(vp); 2071 lastvp = vp; 2072 } 2073 vp = lastvp; 2074 /* 2075 * No usable snapshots found. 2076 */ 2077 if (sn == NULL || vp == NULL) 2078 return; 2079 /* 2080 * Allocate the space for the block hints list. We always want to 2081 * use the list from the newest snapshot. 2082 */ 2083 auio.uio_iov = &aiov; 2084 auio.uio_iovcnt = 1; 2085 aiov.iov_base = (void *)&snaplistsize; 2086 aiov.iov_len = sizeof(snaplistsize); 2087 auio.uio_resid = aiov.iov_len; 2088 auio.uio_offset = 2089 lblktosize(fs, howmany(fs->fs_size, fs->fs_frag)); 2090 auio.uio_segflg = UIO_SYSSPACE; 2091 auio.uio_rw = UIO_READ; 2092 auio.uio_td = td; 2093 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2094 if ((error = VOP_READ(vp, &auio, IO_UNIT, td->td_ucred)) != 0) { 2095 printf("ffs_snapshot_mount: read_1 failed %d\n", error); 2096 VOP_UNLOCK(vp); 2097 return; 2098 } 2099 snapblklist = malloc(snaplistsize * sizeof(daddr_t), 2100 M_UFSMNT, M_WAITOK); 2101 auio.uio_iovcnt = 1; 2102 aiov.iov_base = snapblklist; 2103 aiov.iov_len = snaplistsize * sizeof (daddr_t); 2104 auio.uio_resid = aiov.iov_len; 2105 auio.uio_offset -= sizeof(snaplistsize); 2106 if ((error = VOP_READ(vp, &auio, IO_UNIT, td->td_ucred)) != 0) { 2107 printf("ffs_snapshot_mount: read_2 failed %d\n", error); 2108 VOP_UNLOCK(vp); 2109 free(snapblklist, M_UFSMNT); 2110 return; 2111 } 2112 VOP_UNLOCK(vp); 2113 VI_LOCK(devvp); 2114 sn->sn_listsize = snaplistsize; 2115 sn->sn_blklist = (daddr_t *)snapblklist; 2116 devvp->v_vflag |= VV_COPYONWRITE; 2117 VI_UNLOCK(devvp); 2118 } 2119 2120 /* 2121 * Disassociate snapshot files when unmounting. 2122 */ 2123 void 2124 ffs_snapshot_unmount(struct mount *mp) 2125 { 2126 struct vnode *devvp = VFSTOUFS(mp)->um_devvp; 2127 struct snapdata *sn; 2128 struct inode *xp; 2129 struct vnode *vp; 2130 2131 VI_LOCK(devvp); 2132 sn = devvp->v_rdev->si_snapdata; 2133 while (sn != NULL && (xp = TAILQ_FIRST(&sn->sn_head)) != NULL) { 2134 vp = ITOV(xp); 2135 TAILQ_REMOVE(&sn->sn_head, xp, i_nextsnap); 2136 xp->i_nextsnap.tqe_prev = 0; 2137 lockmgr(&sn->sn_lock, LK_INTERLOCK | LK_EXCLUSIVE, 2138 VI_MTX(devvp)); 2139 VI_LOCK(devvp); 2140 revert_snaplock(vp, devvp, sn); 2141 lockmgr(&vp->v_lock, LK_RELEASE, NULL); 2142 if (xp->i_effnlink > 0) { 2143 VI_UNLOCK(devvp); 2144 vrele(vp); 2145 VI_LOCK(devvp); 2146 } 2147 sn = devvp->v_rdev->si_snapdata; 2148 } 2149 try_free_snapdata(devvp); 2150 VI_UNLOCK(devvp); 2151 } 2152 2153 /* 2154 * Check the buffer block to be belong to device buffer that shall be 2155 * locked after snaplk. devvp shall be locked on entry, and will be 2156 * leaved locked upon exit. 2157 */ 2158 static int 2159 ffs_bp_snapblk(struct vnode *devvp, struct buf *bp) 2160 { 2161 struct snapdata *sn; 2162 struct fs *fs; 2163 ufs2_daddr_t lbn, *snapblklist; 2164 int lower, upper, mid; 2165 2166 ASSERT_VI_LOCKED(devvp, "ffs_bp_snapblk"); 2167 KASSERT(devvp->v_type == VCHR, ("Not a device %p", devvp)); 2168 sn = devvp->v_rdev->si_snapdata; 2169 if (sn == NULL || TAILQ_FIRST(&sn->sn_head) == NULL) 2170 return (0); 2171 fs = ITOFS(TAILQ_FIRST(&sn->sn_head)); 2172 lbn = fragstoblks(fs, dbtofsb(fs, bp->b_blkno)); 2173 snapblklist = sn->sn_blklist; 2174 upper = sn->sn_listsize - 1; 2175 lower = 1; 2176 while (lower <= upper) { 2177 mid = (lower + upper) / 2; 2178 if (snapblklist[mid] == lbn) 2179 break; 2180 if (snapblklist[mid] < lbn) 2181 lower = mid + 1; 2182 else 2183 upper = mid - 1; 2184 } 2185 if (lower <= upper) 2186 return (1); 2187 return (0); 2188 } 2189 2190 void 2191 ffs_bdflush(struct bufobj *bo, struct buf *bp) 2192 { 2193 struct thread *td; 2194 struct vnode *vp, *devvp; 2195 struct buf *nbp; 2196 int bp_bdskip; 2197 2198 if (bo->bo_dirty.bv_cnt <= dirtybufthresh) 2199 return; 2200 2201 td = curthread; 2202 vp = bp->b_vp; 2203 devvp = bo2vnode(bo); 2204 KASSERT(vp == devvp, ("devvp != vp %p %p", bo, bp)); 2205 2206 VI_LOCK(devvp); 2207 bp_bdskip = ffs_bp_snapblk(devvp, bp); 2208 if (bp_bdskip) 2209 bdwriteskip++; 2210 VI_UNLOCK(devvp); 2211 if (bo->bo_dirty.bv_cnt > dirtybufthresh + 10 && !bp_bdskip) { 2212 (void) VOP_FSYNC(vp, MNT_NOWAIT, td); 2213 altbufferflushes++; 2214 } else { 2215 BO_LOCK(bo); 2216 /* 2217 * Try to find a buffer to flush. 2218 */ 2219 TAILQ_FOREACH(nbp, &bo->bo_dirty.bv_hd, b_bobufs) { 2220 if ((nbp->b_vflags & BV_BKGRDINPROG) || 2221 BUF_LOCK(nbp, 2222 LK_EXCLUSIVE | LK_NOWAIT, NULL)) 2223 continue; 2224 if (bp == nbp) 2225 panic("bdwrite: found ourselves"); 2226 BO_UNLOCK(bo); 2227 /* 2228 * Don't countdeps with the bo lock 2229 * held. 2230 */ 2231 if (buf_countdeps(nbp, 0)) { 2232 BO_LOCK(bo); 2233 BUF_UNLOCK(nbp); 2234 continue; 2235 } 2236 if (bp_bdskip) { 2237 VI_LOCK(devvp); 2238 if (!ffs_bp_snapblk(vp, nbp)) { 2239 VI_UNLOCK(devvp); 2240 BO_LOCK(bo); 2241 BUF_UNLOCK(nbp); 2242 continue; 2243 } 2244 VI_UNLOCK(devvp); 2245 } 2246 if (nbp->b_flags & B_CLUSTEROK) { 2247 vfs_bio_awrite(nbp); 2248 } else { 2249 bremfree(nbp); 2250 bawrite(nbp); 2251 } 2252 dirtybufferflushes++; 2253 break; 2254 } 2255 if (nbp == NULL) 2256 BO_UNLOCK(bo); 2257 } 2258 } 2259 2260 /* 2261 * Check for need to copy block that is about to be written, 2262 * copying the block if necessary. 2263 */ 2264 int 2265 ffs_copyonwrite(struct vnode *devvp, struct buf *bp) 2266 { 2267 struct snapdata *sn; 2268 struct buf *ibp, *cbp, *savedcbp = NULL; 2269 struct thread *td = curthread; 2270 struct fs *fs; 2271 struct inode *ip; 2272 struct vnode *vp = NULL; 2273 ufs2_daddr_t lbn, blkno, *snapblklist; 2274 int lower, upper, mid, indiroff, error = 0; 2275 int launched_async_io, prev_norunningbuf; 2276 long saved_runningbufspace; 2277 2278 if (devvp != bp->b_vp && IS_SNAPSHOT(VTOI(bp->b_vp))) 2279 return (0); /* Update on a snapshot file */ 2280 if (td->td_pflags & TDP_COWINPROGRESS) 2281 panic("ffs_copyonwrite: recursive call"); 2282 /* 2283 * First check to see if it is in the preallocated list. 2284 * By doing this check we avoid several potential deadlocks. 2285 */ 2286 VI_LOCK(devvp); 2287 sn = devvp->v_rdev->si_snapdata; 2288 if (sn == NULL || 2289 TAILQ_EMPTY(&sn->sn_head)) { 2290 VI_UNLOCK(devvp); 2291 return (0); /* No snapshot */ 2292 } 2293 ip = TAILQ_FIRST(&sn->sn_head); 2294 fs = ITOFS(ip); 2295 lbn = fragstoblks(fs, dbtofsb(fs, bp->b_blkno)); 2296 if (lbn < UFS_NDADDR) { 2297 VI_UNLOCK(devvp); 2298 return (0); /* Direct blocks are always copied */ 2299 } 2300 snapblklist = sn->sn_blklist; 2301 upper = sn->sn_listsize - 1; 2302 lower = 1; 2303 while (lower <= upper) { 2304 mid = (lower + upper) / 2; 2305 if (snapblklist[mid] == lbn) 2306 break; 2307 if (snapblklist[mid] < lbn) 2308 lower = mid + 1; 2309 else 2310 upper = mid - 1; 2311 } 2312 if (lower <= upper) { 2313 VI_UNLOCK(devvp); 2314 return (0); 2315 } 2316 launched_async_io = 0; 2317 prev_norunningbuf = td->td_pflags & TDP_NORUNNINGBUF; 2318 /* 2319 * Since I/O on bp isn't yet in progress and it may be blocked 2320 * for a long time waiting on snaplk, back it out of 2321 * runningbufspace, possibly waking other threads waiting for space. 2322 */ 2323 saved_runningbufspace = bp->b_runningbufspace; 2324 if (saved_runningbufspace != 0) 2325 runningbufwakeup(bp); 2326 /* 2327 * Not in the precomputed list, so check the snapshots. 2328 */ 2329 while (lockmgr(&sn->sn_lock, LK_INTERLOCK | LK_EXCLUSIVE | LK_SLEEPFAIL, 2330 VI_MTX(devvp)) != 0) { 2331 VI_LOCK(devvp); 2332 sn = devvp->v_rdev->si_snapdata; 2333 if (sn == NULL || 2334 TAILQ_EMPTY(&sn->sn_head)) { 2335 VI_UNLOCK(devvp); 2336 if (saved_runningbufspace != 0) { 2337 bp->b_runningbufspace = saved_runningbufspace; 2338 atomic_add_long(&runningbufspace, 2339 bp->b_runningbufspace); 2340 } 2341 return (0); /* Snapshot gone */ 2342 } 2343 } 2344 TAILQ_FOREACH(ip, &sn->sn_head, i_nextsnap) { 2345 vp = ITOV(ip); 2346 if (DOINGSOFTDEP(vp)) 2347 softdep_prealloc(vp, MNT_WAIT); 2348 /* 2349 * We ensure that everything of our own that needs to be 2350 * copied will be done at the time that ffs_snapshot is 2351 * called. Thus we can skip the check here which can 2352 * deadlock in doing the lookup in UFS_BALLOC. 2353 */ 2354 if (bp->b_vp == vp) 2355 continue; 2356 /* 2357 * Check to see if block needs to be copied. We do not have 2358 * to hold the snapshot lock while doing this lookup as it 2359 * will never require any additional allocations for the 2360 * snapshot inode. 2361 */ 2362 if (lbn < UFS_NDADDR) { 2363 blkno = DIP(ip, i_db[lbn]); 2364 } else { 2365 td->td_pflags |= TDP_COWINPROGRESS | TDP_NORUNNINGBUF; 2366 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)lbn), 2367 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp); 2368 td->td_pflags &= ~TDP_COWINPROGRESS; 2369 if (error) 2370 break; 2371 indiroff = (lbn - UFS_NDADDR) % NINDIR(fs); 2372 if (I_IS_UFS1(ip)) 2373 blkno=((ufs1_daddr_t *)(ibp->b_data))[indiroff]; 2374 else 2375 blkno=((ufs2_daddr_t *)(ibp->b_data))[indiroff]; 2376 bqrelse(ibp); 2377 } 2378 #ifdef INVARIANTS 2379 if (blkno == BLK_SNAP && bp->b_lblkno >= 0) 2380 panic("ffs_copyonwrite: bad copy block"); 2381 #endif 2382 if (blkno != 0) 2383 continue; 2384 /* 2385 * Allocate the block into which to do the copy. Since 2386 * multiple processes may all try to copy the same block, 2387 * we have to recheck our need to do a copy if we sleep 2388 * waiting for the lock. 2389 * 2390 * Because all snapshots on a filesystem share a single 2391 * lock, we ensure that we will never be in competition 2392 * with another process to allocate a block. 2393 */ 2394 td->td_pflags |= TDP_COWINPROGRESS | TDP_NORUNNINGBUF; 2395 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)lbn), 2396 fs->fs_bsize, KERNCRED, 0, &cbp); 2397 td->td_pflags &= ~TDP_COWINPROGRESS; 2398 if (error) 2399 break; 2400 #ifdef DIAGNOSTIC 2401 if (snapdebug) { 2402 printf("Copyonwrite: snapino %ju lbn %jd for ", 2403 (uintmax_t)ip->i_number, (intmax_t)lbn); 2404 if (bp->b_vp == devvp) 2405 printf("fs metadata"); 2406 else 2407 printf("inum %ju", 2408 (uintmax_t)VTOI(bp->b_vp)->i_number); 2409 printf(" lblkno %jd to blkno %jd\n", 2410 (intmax_t)bp->b_lblkno, (intmax_t)cbp->b_blkno); 2411 } 2412 #endif 2413 /* 2414 * If we have already read the old block contents, then 2415 * simply copy them to the new block. Note that we need 2416 * to synchronously write snapshots that have not been 2417 * unlinked, and hence will be visible after a crash, 2418 * to ensure their integrity. At a minimum we ensure the 2419 * integrity of the filesystem metadata, but use the 2420 * dopersistence sysctl-setable flag to decide on the 2421 * persistence needed for file content data. 2422 */ 2423 if (savedcbp != NULL) { 2424 bcopy(savedcbp->b_data, cbp->b_data, fs->fs_bsize); 2425 bawrite(cbp); 2426 if ((devvp == bp->b_vp || bp->b_vp->v_type == VDIR || 2427 dopersistence) && ip->i_effnlink > 0) 2428 (void) ffs_syncvnode(vp, MNT_WAIT, NO_INO_UPDT); 2429 else 2430 launched_async_io = 1; 2431 continue; 2432 } 2433 /* 2434 * Otherwise, read the old block contents into the buffer. 2435 */ 2436 if ((error = readblock(vp, cbp, lbn)) != 0) { 2437 bzero(cbp->b_data, fs->fs_bsize); 2438 bawrite(cbp); 2439 if ((devvp == bp->b_vp || bp->b_vp->v_type == VDIR || 2440 dopersistence) && ip->i_effnlink > 0) 2441 (void) ffs_syncvnode(vp, MNT_WAIT, NO_INO_UPDT); 2442 else 2443 launched_async_io = 1; 2444 break; 2445 } 2446 savedcbp = cbp; 2447 } 2448 /* 2449 * Note that we need to synchronously write snapshots that 2450 * have not been unlinked, and hence will be visible after 2451 * a crash, to ensure their integrity. At a minimum we 2452 * ensure the integrity of the filesystem metadata, but 2453 * use the dopersistence sysctl-setable flag to decide on 2454 * the persistence needed for file content data. 2455 */ 2456 if (savedcbp) { 2457 vp = savedcbp->b_vp; 2458 bawrite(savedcbp); 2459 if ((devvp == bp->b_vp || bp->b_vp->v_type == VDIR || 2460 dopersistence) && VTOI(vp)->i_effnlink > 0) 2461 (void) ffs_syncvnode(vp, MNT_WAIT, NO_INO_UPDT); 2462 else 2463 launched_async_io = 1; 2464 } 2465 lockmgr(vp->v_vnlock, LK_RELEASE, NULL); 2466 td->td_pflags = (td->td_pflags & ~TDP_NORUNNINGBUF) | 2467 prev_norunningbuf; 2468 if (launched_async_io && (td->td_pflags & TDP_NORUNNINGBUF) == 0) 2469 waitrunningbufspace(); 2470 /* 2471 * I/O on bp will now be started, so count it in runningbufspace. 2472 */ 2473 if (saved_runningbufspace != 0) { 2474 bp->b_runningbufspace = saved_runningbufspace; 2475 atomic_add_long(&runningbufspace, bp->b_runningbufspace); 2476 } 2477 return (error); 2478 } 2479 2480 /* 2481 * sync snapshots to force freework records waiting on snapshots to claim 2482 * blocks to free. 2483 */ 2484 void 2485 ffs_sync_snap(struct mount *mp, int waitfor) 2486 { 2487 struct snapdata *sn; 2488 struct vnode *devvp; 2489 struct vnode *vp; 2490 struct inode *ip; 2491 2492 devvp = VFSTOUFS(mp)->um_devvp; 2493 if ((devvp->v_vflag & VV_COPYONWRITE) == 0) 2494 return; 2495 for (;;) { 2496 VI_LOCK(devvp); 2497 sn = devvp->v_rdev->si_snapdata; 2498 if (sn == NULL) { 2499 VI_UNLOCK(devvp); 2500 return; 2501 } 2502 if (lockmgr(&sn->sn_lock, 2503 LK_INTERLOCK | LK_EXCLUSIVE | LK_SLEEPFAIL, 2504 VI_MTX(devvp)) == 0) 2505 break; 2506 } 2507 TAILQ_FOREACH(ip, &sn->sn_head, i_nextsnap) { 2508 vp = ITOV(ip); 2509 ffs_syncvnode(vp, waitfor, NO_INO_UPDT); 2510 } 2511 lockmgr(&sn->sn_lock, LK_RELEASE, NULL); 2512 } 2513 2514 /* 2515 * Read the specified block into the given buffer. 2516 * Much of this boiler-plate comes from bwrite(). 2517 */ 2518 static int 2519 readblock(struct vnode *vp, 2520 struct buf *bp, 2521 ufs2_daddr_t lbn) 2522 { 2523 struct inode *ip; 2524 struct fs *fs; 2525 2526 ip = VTOI(vp); 2527 fs = ITOFS(ip); 2528 2529 bp->b_iocmd = BIO_READ; 2530 bp->b_iooffset = dbtob(fsbtodb(fs, blkstofrags(fs, lbn))); 2531 bp->b_iodone = bdone; 2532 g_vfs_strategy(&ITODEVVP(ip)->v_bufobj, bp); 2533 bufwait(bp); 2534 return (bp->b_error); 2535 } 2536 2537 #endif 2538 2539 /* 2540 * Process file deletes that were deferred by ufs_inactive() due to 2541 * the file system being suspended. Transfer IN_LAZYACCESS into 2542 * IN_MODIFIED for vnodes that were accessed during suspension. 2543 */ 2544 void 2545 process_deferred_inactive(struct mount *mp) 2546 { 2547 struct vnode *vp, *mvp; 2548 struct inode *ip; 2549 int error; 2550 2551 (void) vn_start_secondary_write(NULL, &mp, V_WAIT); 2552 loop: 2553 MNT_VNODE_FOREACH_ALL(vp, mp, mvp) { 2554 /* 2555 * IN_LAZYACCESS is checked here without holding any 2556 * vnode lock, but this flag is set only while holding 2557 * vnode interlock. 2558 */ 2559 if (vp->v_type == VNON || 2560 ((VTOI(vp)->i_flag & IN_LAZYACCESS) == 0 && 2561 ((vp->v_iflag & VI_OWEINACT) == 0 || vp->v_usecount > 0))) { 2562 VI_UNLOCK(vp); 2563 continue; 2564 } 2565 vholdl(vp); 2566 retry_vnode: 2567 error = vn_lock(vp, LK_EXCLUSIVE | LK_INTERLOCK); 2568 if (error != 0) { 2569 vdrop(vp); 2570 if (error == ENOENT) 2571 continue; /* vnode recycled */ 2572 MNT_VNODE_FOREACH_ALL_ABORT(mp, mvp); 2573 goto loop; 2574 } 2575 ip = VTOI(vp); 2576 if ((ip->i_flag & IN_LAZYACCESS) != 0) { 2577 ip->i_flag &= ~IN_LAZYACCESS; 2578 UFS_INODE_SET_FLAG(ip, IN_MODIFIED); 2579 } 2580 VI_LOCK(vp); 2581 error = vinactive(vp); 2582 if (error == ERELOOKUP && vp->v_usecount == 0) { 2583 VI_UNLOCK(vp); 2584 VOP_UNLOCK(vp); 2585 goto retry_vnode; 2586 } 2587 VI_UNLOCK(vp); 2588 VOP_UNLOCK(vp); 2589 vdrop(vp); 2590 } 2591 vn_finished_secondary_write(mp); 2592 } 2593 2594 #ifndef NO_FFS_SNAPSHOT 2595 2596 static struct snapdata * 2597 ffs_snapdata_alloc(void) 2598 { 2599 struct snapdata *sn; 2600 2601 /* 2602 * Fetch a snapdata from the free list if there is one available. 2603 */ 2604 mtx_lock(&snapfree_lock); 2605 sn = LIST_FIRST(&snapfree); 2606 if (sn != NULL) 2607 LIST_REMOVE(sn, sn_link); 2608 mtx_unlock(&snapfree_lock); 2609 if (sn != NULL) 2610 return (sn); 2611 /* 2612 * If there were no free snapdatas allocate one. 2613 */ 2614 sn = malloc(sizeof *sn, M_UFSMNT, M_WAITOK | M_ZERO); 2615 TAILQ_INIT(&sn->sn_head); 2616 lockinit(&sn->sn_lock, PVFS, "snaplk", VLKTIMEOUT, 2617 LK_CANRECURSE | LK_NOSHARE); 2618 return (sn); 2619 } 2620 2621 /* 2622 * The snapdata is never freed because we can not be certain that 2623 * there are no threads sleeping on the snap lock. Persisting 2624 * them permanently avoids costly synchronization in ffs_lock(). 2625 */ 2626 static void 2627 ffs_snapdata_free(struct snapdata *sn) 2628 { 2629 mtx_lock(&snapfree_lock); 2630 LIST_INSERT_HEAD(&snapfree, sn, sn_link); 2631 mtx_unlock(&snapfree_lock); 2632 } 2633 2634 /* Try to free snapdata associated with devvp */ 2635 static void 2636 try_free_snapdata(struct vnode *devvp) 2637 { 2638 struct snapdata *sn; 2639 ufs2_daddr_t *snapblklist; 2640 2641 ASSERT_VI_LOCKED(devvp, "try_free_snapdata"); 2642 sn = devvp->v_rdev->si_snapdata; 2643 2644 if (sn == NULL || TAILQ_FIRST(&sn->sn_head) != NULL || 2645 (devvp->v_vflag & VV_COPYONWRITE) == 0) 2646 return; 2647 2648 devvp->v_rdev->si_snapdata = NULL; 2649 devvp->v_vflag &= ~VV_COPYONWRITE; 2650 lockmgr(&sn->sn_lock, LK_DRAIN|LK_INTERLOCK, VI_MTX(devvp)); 2651 snapblklist = sn->sn_blklist; 2652 sn->sn_blklist = NULL; 2653 sn->sn_listsize = 0; 2654 lockmgr(&sn->sn_lock, LK_RELEASE, NULL); 2655 if (snapblklist != NULL) 2656 free(snapblklist, M_UFSMNT); 2657 ffs_snapdata_free(sn); 2658 VI_LOCK(devvp); 2659 } 2660 2661 /* 2662 * Revert a vnode lock from using the snapshot lock back to its own lock. 2663 * 2664 * Aquire a lock on the vnode's own lock and release the lock on the 2665 * snapshot lock. If there are any recursions on the snapshot lock 2666 * get the same number of recursions on the vnode's own lock. 2667 */ 2668 static void 2669 revert_snaplock(struct vnode *vp, 2670 struct vnode *devvp, 2671 struct snapdata *sn) 2672 { 2673 int i; 2674 2675 ASSERT_VI_LOCKED(devvp, "revert_snaplock"); 2676 /* 2677 * Avoid LOR with snapshot lock. The LK_NOWAIT should 2678 * never fail as the lock is currently unused. Rather than 2679 * panic, we recover by doing the blocking lock. 2680 */ 2681 for (i = 0; i <= sn->sn_lock.lk_recurse; i++) { 2682 if (lockmgr(&vp->v_lock, LK_EXCLUSIVE | LK_NOWAIT | 2683 LK_INTERLOCK, VI_MTX(devvp)) != 0) { 2684 printf("revert_snaplock: Unexpected LK_NOWAIT " 2685 "failure\n"); 2686 lockmgr(&vp->v_lock, LK_EXCLUSIVE | LK_INTERLOCK, 2687 VI_MTX(devvp)); 2688 } 2689 VI_LOCK(devvp); 2690 } 2691 KASSERT(vp->v_vnlock == &sn->sn_lock, 2692 ("revert_snaplock: lost lock mutation")); 2693 vp->v_vnlock = &vp->v_lock; 2694 while (sn->sn_lock.lk_recurse > 0) 2695 lockmgr(&sn->sn_lock, LK_RELEASE, NULL); 2696 lockmgr(&sn->sn_lock, LK_RELEASE, NULL); 2697 } 2698 2699 static struct snapdata * 2700 ffs_snapdata_acquire(struct vnode *devvp) 2701 { 2702 struct snapdata *nsn, *sn; 2703 int error; 2704 2705 /* 2706 * Allocate a free snapdata. This is done before acquiring the 2707 * devvp lock to avoid allocation while the devvp interlock is 2708 * held. 2709 */ 2710 nsn = ffs_snapdata_alloc(); 2711 2712 for (;;) { 2713 VI_LOCK(devvp); 2714 sn = devvp->v_rdev->si_snapdata; 2715 if (sn == NULL) { 2716 /* 2717 * This is the first snapshot on this 2718 * filesystem and we use our pre-allocated 2719 * snapdata. Publish sn with the sn_lock 2720 * owned by us, to avoid the race. 2721 */ 2722 error = lockmgr(&nsn->sn_lock, LK_EXCLUSIVE | 2723 LK_NOWAIT, NULL); 2724 if (error != 0) 2725 panic("leaked sn, lockmgr error %d", error); 2726 sn = devvp->v_rdev->si_snapdata = nsn; 2727 VI_UNLOCK(devvp); 2728 nsn = NULL; 2729 break; 2730 } 2731 2732 /* 2733 * There is a snapshots which already exists on this 2734 * filesystem, grab a reference to the common lock. 2735 */ 2736 error = lockmgr(&sn->sn_lock, LK_INTERLOCK | 2737 LK_EXCLUSIVE | LK_SLEEPFAIL, VI_MTX(devvp)); 2738 if (error == 0) 2739 break; 2740 } 2741 2742 /* 2743 * Free any unused snapdata. 2744 */ 2745 if (nsn != NULL) 2746 ffs_snapdata_free(nsn); 2747 2748 return (sn); 2749 } 2750 2751 #endif 2752