| 1 | /* $NetBSD: ffs_snapshot.c,v 1.143 2016/10/28 20:38:12 jdolecek Exp $ */ |
| 2 | |
| 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 | * @(#)ffs_snapshot.c 8.11 (McKusick) 7/23/00 |
| 36 | * |
| 37 | * from FreeBSD: ffs_snapshot.c,v 1.79 2004/02/13 02:02:06 kuriyama Exp |
| 38 | */ |
| 39 | |
| 40 | #include <sys/cdefs.h> |
| 41 | __KERNEL_RCSID(0, "$NetBSD: ffs_snapshot.c,v 1.143 2016/10/28 20:38:12 jdolecek Exp $" ); |
| 42 | |
| 43 | #if defined(_KERNEL_OPT) |
| 44 | #include "opt_ffs.h" |
| 45 | #include "opt_quota.h" |
| 46 | #endif |
| 47 | |
| 48 | #include <sys/param.h> |
| 49 | #include <sys/kernel.h> |
| 50 | #include <sys/systm.h> |
| 51 | #include <sys/conf.h> |
| 52 | #include <sys/buf.h> |
| 53 | #include <sys/proc.h> |
| 54 | #include <sys/namei.h> |
| 55 | #include <sys/sched.h> |
| 56 | #include <sys/stat.h> |
| 57 | #include <sys/malloc.h> |
| 58 | #include <sys/mount.h> |
| 59 | #include <sys/resource.h> |
| 60 | #include <sys/resourcevar.h> |
| 61 | #include <sys/vnode.h> |
| 62 | #include <sys/kauth.h> |
| 63 | #include <sys/fstrans.h> |
| 64 | #include <sys/wapbl.h> |
| 65 | |
| 66 | #include <miscfs/specfs/specdev.h> |
| 67 | |
| 68 | #include <ufs/ufs/quota.h> |
| 69 | #include <ufs/ufs/ufsmount.h> |
| 70 | #include <ufs/ufs/inode.h> |
| 71 | #include <ufs/ufs/ufs_extern.h> |
| 72 | #include <ufs/ufs/ufs_bswap.h> |
| 73 | #include <ufs/ufs/ufs_wapbl.h> |
| 74 | |
| 75 | #include <ufs/ffs/fs.h> |
| 76 | #include <ufs/ffs/ffs_extern.h> |
| 77 | |
| 78 | #include <uvm/uvm.h> |
| 79 | |
| 80 | TAILQ_HEAD(inodelst, inode); /* List of active snapshots */ |
| 81 | |
| 82 | struct snap_info { |
| 83 | kmutex_t si_lock; /* Lock this snapinfo */ |
| 84 | kmutex_t si_snaplock; /* Snapshot vnode common lock */ |
| 85 | lwp_t *si_owner; /* Snaplock owner */ |
| 86 | struct inodelst si_snapshots; /* List of active snapshots */ |
| 87 | daddr_t *si_snapblklist; /* Snapshot block hints list */ |
| 88 | uint32_t si_gen; /* Incremented on change */ |
| 89 | }; |
| 90 | |
| 91 | #if !defined(FFS_NO_SNAPSHOT) |
| 92 | typedef int (*acctfunc_t) |
| 93 | (struct vnode *, void *, int, int, struct fs *, daddr_t, int); |
| 94 | |
| 95 | static int snapshot_setup(struct mount *, struct vnode *); |
| 96 | static int snapshot_copyfs(struct mount *, struct vnode *, void **); |
| 97 | static int snapshot_expunge(struct mount *, struct vnode *, |
| 98 | struct fs *, daddr_t *, daddr_t **); |
| 99 | static int snapshot_expunge_snap(struct mount *, struct vnode *, |
| 100 | struct fs *, daddr_t); |
| 101 | static int snapshot_writefs(struct mount *, struct vnode *, void *); |
| 102 | static int cgaccount(struct vnode *, int, int *); |
| 103 | static int cgaccount1(int, struct vnode *, void *, int); |
| 104 | static int expunge(struct vnode *, struct inode *, struct fs *, |
| 105 | acctfunc_t, int); |
| 106 | static int indiracct(struct vnode *, struct vnode *, int, daddr_t, |
| 107 | daddr_t, daddr_t, daddr_t, daddr_t, struct fs *, acctfunc_t, int); |
| 108 | static int fullacct(struct vnode *, void *, int, int, struct fs *, |
| 109 | daddr_t, int); |
| 110 | static int snapacct(struct vnode *, void *, int, int, struct fs *, |
| 111 | daddr_t, int); |
| 112 | static int mapacct(struct vnode *, void *, int, int, struct fs *, |
| 113 | daddr_t, int); |
| 114 | #endif /* !defined(FFS_NO_SNAPSHOT) */ |
| 115 | |
| 116 | static int ffs_copyonwrite(void *, struct buf *, bool); |
| 117 | static int snapblkaddr(struct vnode *, daddr_t, daddr_t *); |
| 118 | static int rwfsblk(struct vnode *, int, void *, daddr_t); |
| 119 | static int syncsnap(struct vnode *); |
| 120 | static int wrsnapblk(struct vnode *, void *, daddr_t); |
| 121 | #if !defined(FFS_NO_SNAPSHOT) |
| 122 | static int blocks_in_journal(struct fs *); |
| 123 | #endif |
| 124 | |
| 125 | static inline bool is_active_snapshot(struct snap_info *, struct inode *); |
| 126 | static inline daddr_t db_get(struct inode *, int); |
| 127 | static inline void db_assign(struct inode *, int, daddr_t); |
| 128 | static inline daddr_t ib_get(struct inode *, int); |
| 129 | static inline daddr_t idb_get(struct inode *, void *, int); |
| 130 | static inline void idb_assign(struct inode *, void *, int, daddr_t); |
| 131 | |
| 132 | #ifdef DEBUG |
| 133 | static int snapdebug = 0; |
| 134 | #endif |
| 135 | |
| 136 | int |
| 137 | ffs_snapshot_init(struct ufsmount *ump) |
| 138 | { |
| 139 | struct snap_info *si; |
| 140 | |
| 141 | si = ump->um_snapinfo = kmem_alloc(sizeof(*si), KM_SLEEP); |
| 142 | if (si == NULL) |
| 143 | return ENOMEM; |
| 144 | |
| 145 | TAILQ_INIT(&si->si_snapshots); |
| 146 | mutex_init(&si->si_lock, MUTEX_DEFAULT, IPL_NONE); |
| 147 | mutex_init(&si->si_snaplock, MUTEX_DEFAULT, IPL_NONE); |
| 148 | si->si_owner = NULL; |
| 149 | si->si_gen = 0; |
| 150 | si->si_snapblklist = NULL; |
| 151 | |
| 152 | return 0; |
| 153 | } |
| 154 | |
| 155 | void |
| 156 | ffs_snapshot_fini(struct ufsmount *ump) |
| 157 | { |
| 158 | struct snap_info *si; |
| 159 | |
| 160 | si = ump->um_snapinfo; |
| 161 | ump->um_snapinfo = NULL; |
| 162 | |
| 163 | KASSERT(TAILQ_EMPTY(&si->si_snapshots)); |
| 164 | mutex_destroy(&si->si_lock); |
| 165 | mutex_destroy(&si->si_snaplock); |
| 166 | KASSERT(si->si_snapblklist == NULL); |
| 167 | kmem_free(si, sizeof(*si)); |
| 168 | } |
| 169 | |
| 170 | /* |
| 171 | * Create a snapshot file and initialize it for the filesystem. |
| 172 | * Vnode is locked on entry and return. |
| 173 | */ |
| 174 | int |
| 175 | ffs_snapshot(struct mount *mp, struct vnode *vp, struct timespec *ctime) |
| 176 | { |
| 177 | #if defined(FFS_NO_SNAPSHOT) |
| 178 | return EOPNOTSUPP; |
| 179 | } |
| 180 | #else /* defined(FFS_NO_SNAPSHOT) */ |
| 181 | bool suspended = false; |
| 182 | int error, redo = 0, snaploc; |
| 183 | void *sbbuf = NULL; |
| 184 | daddr_t *snaplist = NULL, snaplistsize = 0; |
| 185 | struct buf *bp, *nbp; |
| 186 | struct fs *copy_fs = NULL; |
| 187 | struct fs *fs = VFSTOUFS(mp)->um_fs; |
| 188 | struct inode *ip = VTOI(vp); |
| 189 | struct lwp *l = curlwp; |
| 190 | struct snap_info *si = VFSTOUFS(mp)->um_snapinfo; |
| 191 | struct timespec ts; |
| 192 | struct timeval starttime; |
| 193 | #ifdef DEBUG |
| 194 | struct timeval endtime; |
| 195 | #endif |
| 196 | struct vnode *devvp = ip->i_devvp; |
| 197 | |
| 198 | /* |
| 199 | * If the vnode already is a snapshot, return. |
| 200 | */ |
| 201 | if ((ip->i_flags & SF_SNAPSHOT)) { |
| 202 | if ((ip->i_flags & SF_SNAPINVAL)) |
| 203 | return EINVAL; |
| 204 | if (ctime) { |
| 205 | ctime->tv_sec = DIP(ip, mtime); |
| 206 | ctime->tv_nsec = DIP(ip, mtimensec); |
| 207 | } |
| 208 | return 0; |
| 209 | } |
| 210 | /* |
| 211 | * Check for free snapshot slot in the superblock. |
| 212 | */ |
| 213 | for (snaploc = 0; snaploc < FSMAXSNAP; snaploc++) |
| 214 | if (fs->fs_snapinum[snaploc] == 0) |
| 215 | break; |
| 216 | if (snaploc == FSMAXSNAP) |
| 217 | return (ENOSPC); |
| 218 | /* |
| 219 | * Prepare the vnode to become a snapshot. |
| 220 | */ |
| 221 | error = snapshot_setup(mp, vp); |
| 222 | if (error) |
| 223 | goto out; |
| 224 | |
| 225 | /* |
| 226 | * Copy all the cylinder group maps. Although the |
| 227 | * filesystem is still active, we hope that only a few |
| 228 | * cylinder groups will change between now and when we |
| 229 | * suspend operations. Thus, we will be able to quickly |
| 230 | * touch up the few cylinder groups that changed during |
| 231 | * the suspension period. |
| 232 | */ |
| 233 | error = cgaccount(vp, 1, NULL); |
| 234 | if (error) |
| 235 | goto out; |
| 236 | |
| 237 | /* |
| 238 | * snapshot is now valid |
| 239 | */ |
| 240 | ip->i_flags &= ~SF_SNAPINVAL; |
| 241 | DIP_ASSIGN(ip, flags, ip->i_flags); |
| 242 | ip->i_flag |= IN_CHANGE | IN_UPDATE; |
| 243 | |
| 244 | /* |
| 245 | * Ensure that the snapshot is completely on disk. |
| 246 | * Since we have marked it as a snapshot it is safe to |
| 247 | * unlock it as no process will be allowed to write to it. |
| 248 | */ |
| 249 | error = VOP_FSYNC(vp, l->l_cred, FSYNC_WAIT, 0, 0); |
| 250 | if (error) |
| 251 | goto out; |
| 252 | VOP_UNLOCK(vp); |
| 253 | /* |
| 254 | * All allocations are done, so we can now suspend the filesystem. |
| 255 | */ |
| 256 | error = vfs_suspend(vp->v_mount, 0); |
| 257 | vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); |
| 258 | if (error) |
| 259 | goto out; |
| 260 | suspended = true; |
| 261 | getmicrotime(&starttime); |
| 262 | /* |
| 263 | * First, copy all the cylinder group maps that have changed. |
| 264 | */ |
| 265 | error = cgaccount(vp, 2, &redo); |
| 266 | if (error) |
| 267 | goto out; |
| 268 | /* |
| 269 | * Create a copy of the superblock and its summary information. |
| 270 | */ |
| 271 | error = snapshot_copyfs(mp, vp, &sbbuf); |
| 272 | if (error) |
| 273 | goto out; |
| 274 | copy_fs = (struct fs *)((char *)sbbuf + ffs_blkoff(fs, fs->fs_sblockloc)); |
| 275 | /* |
| 276 | * Expunge unlinked files from our view. |
| 277 | */ |
| 278 | error = snapshot_expunge(mp, vp, copy_fs, &snaplistsize, &snaplist); |
| 279 | if (error) |
| 280 | goto out; |
| 281 | /* |
| 282 | * Record snapshot inode. Since this is the newest snapshot, |
| 283 | * it must be placed at the end of the list. |
| 284 | */ |
| 285 | if (ip->i_nlink > 0) |
| 286 | fs->fs_snapinum[snaploc] = ip->i_number; |
| 287 | |
| 288 | mutex_enter(&si->si_lock); |
| 289 | if (is_active_snapshot(si, ip)) |
| 290 | panic("ffs_snapshot: %" PRIu64" already on list" , ip->i_number); |
| 291 | TAILQ_INSERT_TAIL(&si->si_snapshots, ip, i_nextsnap); |
| 292 | if (TAILQ_FIRST(&si->si_snapshots) == ip) { |
| 293 | /* |
| 294 | * If this is the first snapshot on this filesystem, put the |
| 295 | * preliminary list in place and establish the cow handler. |
| 296 | */ |
| 297 | si->si_snapblklist = snaplist; |
| 298 | fscow_establish(mp, ffs_copyonwrite, devvp); |
| 299 | } |
| 300 | si->si_gen++; |
| 301 | mutex_exit(&si->si_lock); |
| 302 | |
| 303 | vp->v_vflag |= VV_SYSTEM; |
| 304 | /* |
| 305 | * Set the mtime to the time the snapshot has been taken. |
| 306 | */ |
| 307 | TIMEVAL_TO_TIMESPEC(&starttime, &ts); |
| 308 | if (ctime) |
| 309 | *ctime = ts; |
| 310 | DIP_ASSIGN(ip, mtime, ts.tv_sec); |
| 311 | DIP_ASSIGN(ip, mtimensec, ts.tv_nsec); |
| 312 | ip->i_flag |= IN_CHANGE | IN_UPDATE; |
| 313 | /* |
| 314 | * Copy allocation information from all snapshots and then |
| 315 | * expunge them from our view. |
| 316 | */ |
| 317 | error = snapshot_expunge_snap(mp, vp, copy_fs, snaplistsize); |
| 318 | if (error) |
| 319 | goto out; |
| 320 | /* |
| 321 | * Write the superblock and its summary information to the snapshot. |
| 322 | */ |
| 323 | error = snapshot_writefs(mp, vp, sbbuf); |
| 324 | if (error) |
| 325 | goto out; |
| 326 | /* |
| 327 | * We're nearly done, ensure that the snapshot is completely on disk. |
| 328 | */ |
| 329 | error = VOP_FSYNC(vp, l->l_cred, FSYNC_WAIT, 0, 0); |
| 330 | if (error) |
| 331 | goto out; |
| 332 | /* |
| 333 | * Invalidate and free all pages on the snapshot vnode. |
| 334 | * We will read and write through the buffercache. |
| 335 | */ |
| 336 | mutex_enter(vp->v_interlock); |
| 337 | error = VOP_PUTPAGES(vp, 0, 0, |
| 338 | PGO_ALLPAGES | PGO_CLEANIT | PGO_SYNCIO | PGO_FREE); |
| 339 | if (error) |
| 340 | goto out; |
| 341 | /* |
| 342 | * Invalidate short ( < fs_bsize ) buffers. We will always read |
| 343 | * full size buffers later. |
| 344 | */ |
| 345 | mutex_enter(&bufcache_lock); |
| 346 | KASSERT(LIST_FIRST(&vp->v_dirtyblkhd) == NULL); |
| 347 | for (bp = LIST_FIRST(&vp->v_cleanblkhd); bp; bp = nbp) { |
| 348 | nbp = LIST_NEXT(bp, b_vnbufs); |
| 349 | if (bp->b_bcount == fs->fs_bsize) |
| 350 | continue; |
| 351 | error = bbusy(bp, false, 0, NULL); |
| 352 | if (error != 0) { |
| 353 | if (error == EPASSTHROUGH) { |
| 354 | nbp = LIST_FIRST(&vp->v_cleanblkhd); |
| 355 | continue; |
| 356 | } |
| 357 | break; |
| 358 | } |
| 359 | brelsel(bp, BC_INVAL | BC_VFLUSH); |
| 360 | } |
| 361 | mutex_exit(&bufcache_lock); |
| 362 | |
| 363 | out: |
| 364 | if (sbbuf != NULL) { |
| 365 | free(copy_fs->fs_csp, M_UFSMNT); |
| 366 | free(sbbuf, M_UFSMNT); |
| 367 | } |
| 368 | if (fs->fs_active != NULL) { |
| 369 | free(fs->fs_active, M_DEVBUF); |
| 370 | fs->fs_active = NULL; |
| 371 | } |
| 372 | |
| 373 | mutex_enter(&si->si_lock); |
| 374 | if (snaplist != NULL) { |
| 375 | if (si->si_snapblklist == snaplist) |
| 376 | si->si_snapblklist = NULL; |
| 377 | free(snaplist, M_UFSMNT); |
| 378 | } |
| 379 | if (error) { |
| 380 | fs->fs_snapinum[snaploc] = 0; |
| 381 | } else { |
| 382 | /* |
| 383 | * As this is the newest list, it is the most inclusive, so |
| 384 | * should replace the previous list. |
| 385 | */ |
| 386 | si->si_snapblklist = ip->i_snapblklist; |
| 387 | } |
| 388 | si->si_gen++; |
| 389 | mutex_exit(&si->si_lock); |
| 390 | |
| 391 | if (suspended) { |
| 392 | VOP_UNLOCK(vp); |
| 393 | vfs_resume(vp->v_mount); |
| 394 | vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); |
| 395 | #ifdef DEBUG |
| 396 | getmicrotime(&endtime); |
| 397 | timersub(&endtime, &starttime, &endtime); |
| 398 | printf("%s: suspended %lld.%03d sec, redo %d of %d\n" , |
| 399 | mp->mnt_stat.f_mntonname, (long long)endtime.tv_sec, |
| 400 | endtime.tv_usec / 1000, redo, fs->fs_ncg); |
| 401 | #endif |
| 402 | } |
| 403 | if (error) { |
| 404 | if (UFS_WAPBL_BEGIN(mp) == 0) { |
| 405 | /* |
| 406 | * We depend on ffs_truncate() to call ffs_snapremove() |
| 407 | * before it may return an error. On failed |
| 408 | * ffs_truncate() we have normal file with leaked |
| 409 | * (meta-) data, but no snapshot to use. |
| 410 | */ |
| 411 | (void) ffs_truncate(vp, (off_t)0, 0, NOCRED); |
| 412 | UFS_WAPBL_END(mp); |
| 413 | } |
| 414 | } else if (ip->i_nlink > 0) |
| 415 | vref(vp); |
| 416 | return (error); |
| 417 | } |
| 418 | |
| 419 | /* |
| 420 | * Prepare vnode to become a snapshot. |
| 421 | */ |
| 422 | static int |
| 423 | snapshot_setup(struct mount *mp, struct vnode *vp) |
| 424 | { |
| 425 | int error, n, len, loc, cg; |
| 426 | daddr_t blkno, numblks; |
| 427 | struct buf *ibp, *nbp; |
| 428 | struct fs *fs = VFSTOUFS(mp)->um_fs; |
| 429 | struct lwp *l = curlwp; |
| 430 | const int wbreak = blocks_in_journal(fs)/8; |
| 431 | struct inode *ip = VTOI(vp); |
| 432 | |
| 433 | /* |
| 434 | * Check mount, readonly reference and owner. |
| 435 | */ |
| 436 | if (vp->v_mount != mp) |
| 437 | return EXDEV; |
| 438 | if (vp->v_writecount != 0) |
| 439 | return EBUSY; |
| 440 | error = kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_FS_SNAPSHOT, |
| 441 | 0, mp, vp, NULL); |
| 442 | if (error) |
| 443 | return EACCES; |
| 444 | |
| 445 | if (vp->v_size != 0) { |
| 446 | /* |
| 447 | * Must completely truncate the file here. Allocated |
| 448 | * blocks on a snapshot mean that block has been copied |
| 449 | * on write, see ffs_copyonwrite() testing "blkno != 0" |
| 450 | */ |
| 451 | error = ufs_truncate_retry(vp, 0, NOCRED); |
| 452 | if (error) |
| 453 | return error; |
| 454 | } |
| 455 | |
| 456 | /* Change inode to snapshot type file. */ |
| 457 | error = UFS_WAPBL_BEGIN(mp); |
| 458 | if (error) |
| 459 | return error; |
| 460 | #if defined(QUOTA) || defined(QUOTA2) |
| 461 | /* shapshot inodes are not accounted in quotas */ |
| 462 | chkiq(ip, -1, l->l_cred, 0); |
| 463 | #endif |
| 464 | ip->i_flags |= (SF_SNAPSHOT | SF_SNAPINVAL); |
| 465 | DIP_ASSIGN(ip, flags, ip->i_flags); |
| 466 | ip->i_flag |= IN_CHANGE | IN_UPDATE; |
| 467 | ffs_update(vp, NULL, NULL, UPDATE_WAIT); |
| 468 | UFS_WAPBL_END(mp); |
| 469 | |
| 470 | KASSERT(ip->i_flags & SF_SNAPSHOT); |
| 471 | /* |
| 472 | * Write an empty list of preallocated blocks to the end of |
| 473 | * the snapshot to set size to at least that of the filesystem. |
| 474 | */ |
| 475 | numblks = howmany(fs->fs_size, fs->fs_frag); |
| 476 | blkno = 1; |
| 477 | blkno = ufs_rw64(blkno, UFS_FSNEEDSWAP(fs)); |
| 478 | error = vn_rdwr(UIO_WRITE, vp, |
| 479 | (void *)&blkno, sizeof(blkno), ffs_lblktosize(fs, (off_t)numblks), |
| 480 | UIO_SYSSPACE, IO_NODELOCKED|IO_UNIT, l->l_cred, NULL, NULL); |
| 481 | if (error) |
| 482 | return error; |
| 483 | /* |
| 484 | * Preallocate critical data structures so that we can copy |
| 485 | * them in without further allocation after we suspend all |
| 486 | * operations on the filesystem. We would like to just release |
| 487 | * the allocated buffers without writing them since they will |
| 488 | * be filled in below once we are ready to go, but this upsets |
| 489 | * the soft update code, so we go ahead and write the new buffers. |
| 490 | * |
| 491 | * Allocate all indirect blocks and mark all of them as not |
| 492 | * needing to be copied. |
| 493 | */ |
| 494 | error = UFS_WAPBL_BEGIN(mp); |
| 495 | if (error) |
| 496 | return error; |
| 497 | for (blkno = UFS_NDADDR, n = 0; blkno < numblks; blkno += FFS_NINDIR(fs)) { |
| 498 | error = ffs_balloc(vp, ffs_lblktosize(fs, (off_t)blkno), |
| 499 | fs->fs_bsize, l->l_cred, B_METAONLY, &ibp); |
| 500 | if (error) |
| 501 | goto out; |
| 502 | brelse(ibp, 0); |
| 503 | if (wbreak > 0 && (++n % wbreak) == 0) { |
| 504 | UFS_WAPBL_END(mp); |
| 505 | error = UFS_WAPBL_BEGIN(mp); |
| 506 | if (error) |
| 507 | return error; |
| 508 | } |
| 509 | } |
| 510 | /* |
| 511 | * Allocate copies for the superblock and its summary information. |
| 512 | */ |
| 513 | error = ffs_balloc(vp, fs->fs_sblockloc, fs->fs_sbsize, l->l_cred, |
| 514 | 0, &nbp); |
| 515 | if (error) |
| 516 | goto out; |
| 517 | bawrite(nbp); |
| 518 | blkno = ffs_fragstoblks(fs, fs->fs_csaddr); |
| 519 | len = howmany(fs->fs_cssize, fs->fs_bsize); |
| 520 | for (loc = 0; loc < len; loc++) { |
| 521 | error = ffs_balloc(vp, ffs_lblktosize(fs, (off_t)(blkno + loc)), |
| 522 | fs->fs_bsize, l->l_cred, 0, &nbp); |
| 523 | if (error) |
| 524 | goto out; |
| 525 | bawrite(nbp); |
| 526 | if (wbreak > 0 && (++n % wbreak) == 0) { |
| 527 | UFS_WAPBL_END(mp); |
| 528 | error = UFS_WAPBL_BEGIN(mp); |
| 529 | if (error) |
| 530 | return error; |
| 531 | } |
| 532 | } |
| 533 | /* |
| 534 | * Allocate all cylinder group blocks. |
| 535 | */ |
| 536 | for (cg = 0; cg < fs->fs_ncg; cg++) { |
| 537 | error = ffs_balloc(vp, ffs_lfragtosize(fs, cgtod(fs, cg)), |
| 538 | fs->fs_bsize, l->l_cred, 0, &nbp); |
| 539 | if (error) |
| 540 | goto out; |
| 541 | bawrite(nbp); |
| 542 | if (wbreak > 0 && (++n % wbreak) == 0) { |
| 543 | UFS_WAPBL_END(mp); |
| 544 | error = UFS_WAPBL_BEGIN(mp); |
| 545 | if (error) |
| 546 | return error; |
| 547 | } |
| 548 | } |
| 549 | |
| 550 | out: |
| 551 | UFS_WAPBL_END(mp); |
| 552 | return error; |
| 553 | } |
| 554 | |
| 555 | /* |
| 556 | * Create a copy of the superblock and its summary information. |
| 557 | * It is up to the caller to free copyfs and copy_fs->fs_csp. |
| 558 | */ |
| 559 | static int |
| 560 | snapshot_copyfs(struct mount *mp, struct vnode *vp, void **sbbuf) |
| 561 | { |
| 562 | int error, i, len, loc, size; |
| 563 | void *space; |
| 564 | int32_t *lp; |
| 565 | struct buf *bp; |
| 566 | struct fs *copyfs, *fs = VFSTOUFS(mp)->um_fs; |
| 567 | struct vnode *devvp = VTOI(vp)->i_devvp; |
| 568 | |
| 569 | /* |
| 570 | * Grab a copy of the superblock and its summary information. |
| 571 | * We delay writing it until the suspension is released below. |
| 572 | */ |
| 573 | *sbbuf = malloc(fs->fs_bsize, M_UFSMNT, M_WAITOK); |
| 574 | loc = ffs_blkoff(fs, fs->fs_sblockloc); |
| 575 | if (loc > 0) |
| 576 | memset(*sbbuf, 0, loc); |
| 577 | copyfs = (struct fs *)((char *)(*sbbuf) + loc); |
| 578 | memcpy(copyfs, fs, fs->fs_sbsize); |
| 579 | size = fs->fs_bsize < SBLOCKSIZE ? fs->fs_bsize : SBLOCKSIZE; |
| 580 | if (fs->fs_sbsize < size) |
| 581 | memset((char *)(*sbbuf) + loc + fs->fs_sbsize, 0, |
| 582 | size - fs->fs_sbsize); |
| 583 | size = ffs_blkroundup(fs, fs->fs_cssize); |
| 584 | if (fs->fs_contigsumsize > 0) |
| 585 | size += fs->fs_ncg * sizeof(int32_t); |
| 586 | space = malloc(size, M_UFSMNT, M_WAITOK); |
| 587 | copyfs->fs_csp = space; |
| 588 | memcpy(copyfs->fs_csp, fs->fs_csp, fs->fs_cssize); |
| 589 | space = (char *)space + fs->fs_cssize; |
| 590 | loc = howmany(fs->fs_cssize, fs->fs_fsize); |
| 591 | i = fs->fs_frag - loc % fs->fs_frag; |
| 592 | len = (i == fs->fs_frag) ? 0 : i * fs->fs_fsize; |
| 593 | if (len > 0) { |
| 594 | if ((error = bread(devvp, FFS_FSBTODB(fs, fs->fs_csaddr + loc), |
| 595 | len, 0, &bp)) != 0) { |
| 596 | free(copyfs->fs_csp, M_UFSMNT); |
| 597 | free(*sbbuf, M_UFSMNT); |
| 598 | *sbbuf = NULL; |
| 599 | return error; |
| 600 | } |
| 601 | memcpy(space, bp->b_data, (u_int)len); |
| 602 | space = (char *)space + len; |
| 603 | brelse(bp, BC_INVAL | BC_NOCACHE); |
| 604 | } |
| 605 | if (fs->fs_contigsumsize > 0) { |
| 606 | copyfs->fs_maxcluster = lp = space; |
| 607 | for (i = 0; i < fs->fs_ncg; i++) |
| 608 | *lp++ = fs->fs_contigsumsize; |
| 609 | } |
| 610 | if (mp->mnt_wapbl) |
| 611 | copyfs->fs_flags &= ~FS_DOWAPBL; |
| 612 | return 0; |
| 613 | } |
| 614 | |
| 615 | struct snapshot_expunge_ctx { |
| 616 | struct vnode *logvp; |
| 617 | struct lwp *l; |
| 618 | struct vnode *vp; |
| 619 | struct fs *copy_fs; |
| 620 | }; |
| 621 | |
| 622 | static bool |
| 623 | snapshot_expunge_selector(void *cl, struct vnode *xvp) |
| 624 | { |
| 625 | struct vattr vat; |
| 626 | struct snapshot_expunge_ctx *c = cl; |
| 627 | struct inode *xp; |
| 628 | |
| 629 | xp = VTOI(xvp); |
| 630 | if (xvp->v_type == VNON || VTOI(xvp) == NULL || |
| 631 | (xp->i_flags & SF_SNAPSHOT)) |
| 632 | return false; |
| 633 | #ifdef DEBUG |
| 634 | if (snapdebug) |
| 635 | vprint("ffs_snapshot: busy vnode" , xvp); |
| 636 | #endif |
| 637 | |
| 638 | if (xvp == c->logvp) |
| 639 | return true; |
| 640 | |
| 641 | if (VOP_GETATTR(xvp, &vat, c->l->l_cred) == 0 && |
| 642 | vat.va_nlink > 0) |
| 643 | return false; |
| 644 | |
| 645 | if (ffs_checkfreefile(c->copy_fs, c->vp, xp->i_number)) |
| 646 | return false; |
| 647 | |
| 648 | return true; |
| 649 | } |
| 650 | |
| 651 | /* |
| 652 | * We must check for active files that have been unlinked (e.g., with a zero |
| 653 | * link count). We have to expunge all trace of these files from the snapshot |
| 654 | * so that they are not reclaimed prematurely by fsck or unnecessarily dumped. |
| 655 | * Note that we skip unlinked snapshot files as they will be handled separately. |
| 656 | * Calculate the snapshot list size and create a preliminary list. |
| 657 | */ |
| 658 | static int |
| 659 | snapshot_expunge(struct mount *mp, struct vnode *vp, struct fs *copy_fs, |
| 660 | daddr_t *snaplistsize, daddr_t **snaplist) |
| 661 | { |
| 662 | int cg, error = 0, len, loc; |
| 663 | daddr_t blkno, *blkp; |
| 664 | struct fs *fs = VFSTOUFS(mp)->um_fs; |
| 665 | struct inode *xp; |
| 666 | struct lwp *l = curlwp; |
| 667 | struct vnode *logvp = NULL, *xvp; |
| 668 | struct vnode_iterator *marker; |
| 669 | struct snapshot_expunge_ctx ctx; |
| 670 | |
| 671 | *snaplist = NULL; |
| 672 | /* |
| 673 | * Get the log inode if any. |
| 674 | */ |
| 675 | if ((fs->fs_flags & FS_DOWAPBL) && |
| 676 | fs->fs_journal_location == UFS_WAPBL_JOURNALLOC_IN_FILESYSTEM) { |
| 677 | error = VFS_VGET(mp, |
| 678 | fs->fs_journallocs[UFS_WAPBL_INFS_INO], &logvp); |
| 679 | if (error) |
| 680 | goto out; |
| 681 | } |
| 682 | /* |
| 683 | * We also calculate the needed size for the snapshot list. |
| 684 | */ |
| 685 | *snaplistsize = fs->fs_ncg + howmany(fs->fs_cssize, fs->fs_bsize) + |
| 686 | FSMAXSNAP + 1 /* superblock */ + 1 /* last block */ + 1 /* size */; |
| 687 | |
| 688 | vfs_vnode_iterator_init(mp, &marker); |
| 689 | ctx.logvp = logvp; |
| 690 | ctx.l = l; |
| 691 | ctx.vp = vp; |
| 692 | ctx.copy_fs = copy_fs; |
| 693 | while ((xvp = vfs_vnode_iterator_next(marker, snapshot_expunge_selector, |
| 694 | &ctx))) |
| 695 | { |
| 696 | /* |
| 697 | * If there is a fragment, clear it here. |
| 698 | */ |
| 699 | xp = VTOI(xvp); |
| 700 | blkno = 0; |
| 701 | loc = howmany(xp->i_size, fs->fs_bsize) - 1; |
| 702 | if (loc < UFS_NDADDR) { |
| 703 | len = ffs_fragroundup(fs, ffs_blkoff(fs, xp->i_size)); |
| 704 | if (len > 0 && len < fs->fs_bsize) { |
| 705 | error = UFS_WAPBL_BEGIN(mp); |
| 706 | if (error) { |
| 707 | vrele(xvp); |
| 708 | vfs_vnode_iterator_destroy(marker); |
| 709 | goto out; |
| 710 | } |
| 711 | ffs_blkfree_snap(copy_fs, vp, db_get(xp, loc), |
| 712 | len, xp->i_number); |
| 713 | blkno = db_get(xp, loc); |
| 714 | db_assign(xp, loc, 0); |
| 715 | UFS_WAPBL_END(mp); |
| 716 | } |
| 717 | } |
| 718 | *snaplistsize += 1; |
| 719 | error = expunge(vp, xp, copy_fs, fullacct, BLK_NOCOPY); |
| 720 | if (blkno) |
| 721 | db_assign(xp, loc, blkno); |
| 722 | if (!error) { |
| 723 | error = UFS_WAPBL_BEGIN(mp); |
| 724 | if (!error) { |
| 725 | error = ffs_freefile_snap(copy_fs, vp, |
| 726 | xp->i_number, xp->i_mode); |
| 727 | UFS_WAPBL_END(mp); |
| 728 | } |
| 729 | } |
| 730 | vrele(xvp); |
| 731 | if (error) { |
| 732 | vfs_vnode_iterator_destroy(marker); |
| 733 | goto out; |
| 734 | } |
| 735 | } |
| 736 | vfs_vnode_iterator_destroy(marker); |
| 737 | |
| 738 | /* |
| 739 | * Create a preliminary list of preallocated snapshot blocks. |
| 740 | */ |
| 741 | *snaplist = malloc(*snaplistsize * sizeof(daddr_t), M_UFSMNT, M_WAITOK); |
| 742 | blkp = &(*snaplist)[1]; |
| 743 | *blkp++ = ffs_lblkno(fs, fs->fs_sblockloc); |
| 744 | blkno = ffs_fragstoblks(fs, fs->fs_csaddr); |
| 745 | for (cg = 0; cg < fs->fs_ncg; cg++) { |
| 746 | if (ffs_fragstoblks(fs, cgtod(fs, cg)) > blkno) |
| 747 | break; |
| 748 | *blkp++ = ffs_fragstoblks(fs, cgtod(fs, cg)); |
| 749 | } |
| 750 | len = howmany(fs->fs_cssize, fs->fs_bsize); |
| 751 | for (loc = 0; loc < len; loc++) |
| 752 | *blkp++ = blkno + loc; |
| 753 | for (; cg < fs->fs_ncg; cg++) |
| 754 | *blkp++ = ffs_fragstoblks(fs, cgtod(fs, cg)); |
| 755 | (*snaplist)[0] = blkp - &(*snaplist)[0]; |
| 756 | |
| 757 | out: |
| 758 | if (logvp != NULL) |
| 759 | vput(logvp); |
| 760 | if (error && *snaplist != NULL) { |
| 761 | free(*snaplist, M_UFSMNT); |
| 762 | *snaplist = NULL; |
| 763 | } |
| 764 | |
| 765 | return error; |
| 766 | } |
| 767 | |
| 768 | /* |
| 769 | * Copy allocation information from all the snapshots in this snapshot and |
| 770 | * then expunge them from its view. Also, collect the list of allocated |
| 771 | * blocks in i_snapblklist. |
| 772 | */ |
| 773 | static int |
| 774 | snapshot_expunge_snap(struct mount *mp, struct vnode *vp, |
| 775 | struct fs *copy_fs, daddr_t snaplistsize) |
| 776 | { |
| 777 | int error = 0, i; |
| 778 | daddr_t numblks, *snaplist = NULL; |
| 779 | struct fs *fs = VFSTOUFS(mp)->um_fs; |
| 780 | struct inode *ip = VTOI(vp), *xp; |
| 781 | struct lwp *l = curlwp; |
| 782 | struct snap_info *si = VFSTOUFS(mp)->um_snapinfo; |
| 783 | |
| 784 | TAILQ_FOREACH(xp, &si->si_snapshots, i_nextsnap) { |
| 785 | if (xp != ip) { |
| 786 | error = expunge(vp, xp, fs, snapacct, BLK_SNAP); |
| 787 | if (error) |
| 788 | break; |
| 789 | } |
| 790 | if (xp->i_nlink != 0) |
| 791 | continue; |
| 792 | error = UFS_WAPBL_BEGIN(mp); |
| 793 | if (error) |
| 794 | break; |
| 795 | error = ffs_freefile_snap(copy_fs, vp, xp->i_number, xp->i_mode); |
| 796 | UFS_WAPBL_END(mp); |
| 797 | if (error) |
| 798 | break; |
| 799 | } |
| 800 | if (error) |
| 801 | goto out; |
| 802 | /* |
| 803 | * Allocate space for the full list of preallocated snapshot blocks. |
| 804 | */ |
| 805 | snaplist = malloc(snaplistsize * sizeof(daddr_t), M_UFSMNT, M_WAITOK); |
| 806 | ip->i_snapblklist = &snaplist[1]; |
| 807 | /* |
| 808 | * Expunge the blocks used by the snapshots from the set of |
| 809 | * blocks marked as used in the snapshot bitmaps. Also, collect |
| 810 | * the list of allocated blocks in i_snapblklist. |
| 811 | */ |
| 812 | error = expunge(vp, ip, copy_fs, mapacct, BLK_SNAP); |
| 813 | if (error) |
| 814 | goto out; |
| 815 | if (snaplistsize < ip->i_snapblklist - snaplist) |
| 816 | panic("ffs_snapshot: list too small" ); |
| 817 | snaplistsize = ip->i_snapblklist - snaplist; |
| 818 | snaplist[0] = snaplistsize; |
| 819 | ip->i_snapblklist = &snaplist[0]; |
| 820 | /* |
| 821 | * Write out the list of allocated blocks to the end of the snapshot. |
| 822 | */ |
| 823 | numblks = howmany(fs->fs_size, fs->fs_frag); |
| 824 | for (i = 0; i < snaplistsize; i++) |
| 825 | snaplist[i] = ufs_rw64(snaplist[i], UFS_FSNEEDSWAP(fs)); |
| 826 | error = vn_rdwr(UIO_WRITE, vp, (void *)snaplist, |
| 827 | snaplistsize * sizeof(daddr_t), ffs_lblktosize(fs, (off_t)numblks), |
| 828 | UIO_SYSSPACE, IO_NODELOCKED | IO_UNIT, l->l_cred, NULL, NULL); |
| 829 | for (i = 0; i < snaplistsize; i++) |
| 830 | snaplist[i] = ufs_rw64(snaplist[i], UFS_FSNEEDSWAP(fs)); |
| 831 | out: |
| 832 | if (error && snaplist != NULL) { |
| 833 | free(snaplist, M_UFSMNT); |
| 834 | ip->i_snapblklist = NULL; |
| 835 | } |
| 836 | return error; |
| 837 | } |
| 838 | |
| 839 | /* |
| 840 | * Write the superblock and its summary information to the snapshot. |
| 841 | * Make sure, the first UFS_NDADDR blocks get copied to the snapshot. |
| 842 | */ |
| 843 | static int |
| 844 | snapshot_writefs(struct mount *mp, struct vnode *vp, void *sbbuf) |
| 845 | { |
| 846 | int error, len, loc; |
| 847 | void *space; |
| 848 | daddr_t blkno; |
| 849 | struct buf *bp; |
| 850 | struct fs *copyfs, *fs = VFSTOUFS(mp)->um_fs; |
| 851 | struct inode *ip = VTOI(vp); |
| 852 | struct lwp *l = curlwp; |
| 853 | |
| 854 | copyfs = (struct fs *)((char *)sbbuf + ffs_blkoff(fs, fs->fs_sblockloc)); |
| 855 | |
| 856 | /* |
| 857 | * Write the superblock and its summary information |
| 858 | * to the snapshot. |
| 859 | */ |
| 860 | blkno = ffs_fragstoblks(fs, fs->fs_csaddr); |
| 861 | len = howmany(fs->fs_cssize, fs->fs_bsize); |
| 862 | space = copyfs->fs_csp; |
| 863 | #ifdef FFS_EI |
| 864 | if (UFS_FSNEEDSWAP(fs)) { |
| 865 | ffs_sb_swap(copyfs, copyfs); |
| 866 | ffs_csum_swap(space, space, fs->fs_cssize); |
| 867 | } |
| 868 | #endif |
| 869 | error = UFS_WAPBL_BEGIN(mp); |
| 870 | if (error) |
| 871 | return error; |
| 872 | for (loc = 0; loc < len; loc++) { |
| 873 | error = bread(vp, blkno + loc, fs->fs_bsize, |
| 874 | B_MODIFY, &bp); |
| 875 | if (error) { |
| 876 | break; |
| 877 | } |
| 878 | memcpy(bp->b_data, space, fs->fs_bsize); |
| 879 | space = (char *)space + fs->fs_bsize; |
| 880 | bawrite(bp); |
| 881 | } |
| 882 | if (error) |
| 883 | goto out; |
| 884 | error = bread(vp, ffs_lblkno(fs, fs->fs_sblockloc), |
| 885 | fs->fs_bsize, B_MODIFY, &bp); |
| 886 | if (error) { |
| 887 | goto out; |
| 888 | } else { |
| 889 | memcpy(bp->b_data, sbbuf, fs->fs_bsize); |
| 890 | bawrite(bp); |
| 891 | } |
| 892 | /* |
| 893 | * Copy the first UFS_NDADDR blocks to the snapshot so |
| 894 | * ffs_copyonwrite() and ffs_snapblkfree() will always work on |
| 895 | * indirect blocks. |
| 896 | */ |
| 897 | for (loc = 0; loc < UFS_NDADDR; loc++) { |
| 898 | if (db_get(ip, loc) != 0) |
| 899 | continue; |
| 900 | error = ffs_balloc(vp, ffs_lblktosize(fs, (off_t)loc), |
| 901 | fs->fs_bsize, l->l_cred, 0, &bp); |
| 902 | if (error) |
| 903 | break; |
| 904 | error = rwfsblk(vp, B_READ, bp->b_data, loc); |
| 905 | if (error) { |
| 906 | brelse(bp, 0); |
| 907 | break; |
| 908 | } |
| 909 | bawrite(bp); |
| 910 | } |
| 911 | |
| 912 | out: |
| 913 | UFS_WAPBL_END(mp); |
| 914 | return error; |
| 915 | } |
| 916 | |
| 917 | /* |
| 918 | * Copy all cylinder group maps. |
| 919 | */ |
| 920 | static int |
| 921 | cgaccount(struct vnode *vp, int passno, int *redo) |
| 922 | { |
| 923 | int cg, error = 0; |
| 924 | struct buf *nbp; |
| 925 | struct fs *fs = VTOI(vp)->i_fs; |
| 926 | |
| 927 | if (redo != NULL) |
| 928 | *redo = 0; |
| 929 | if (passno == 1) |
| 930 | fs->fs_active = malloc(howmany(fs->fs_ncg, NBBY), |
| 931 | M_DEVBUF, M_WAITOK | M_ZERO); |
| 932 | for (cg = 0; cg < fs->fs_ncg; cg++) { |
| 933 | if (passno == 2 && ACTIVECG_ISSET(fs, cg)) |
| 934 | continue; |
| 935 | |
| 936 | if (redo != NULL) |
| 937 | *redo += 1; |
| 938 | error = UFS_WAPBL_BEGIN(vp->v_mount); |
| 939 | if (error) |
| 940 | return error; |
| 941 | error = ffs_balloc(vp, ffs_lfragtosize(fs, cgtod(fs, cg)), |
| 942 | fs->fs_bsize, curlwp->l_cred, 0, &nbp); |
| 943 | if (error) { |
| 944 | UFS_WAPBL_END(vp->v_mount); |
| 945 | break; |
| 946 | } |
| 947 | error = cgaccount1(cg, vp, nbp->b_data, passno); |
| 948 | bawrite(nbp); |
| 949 | UFS_WAPBL_END(vp->v_mount); |
| 950 | if (error) |
| 951 | break; |
| 952 | } |
| 953 | return error; |
| 954 | } |
| 955 | |
| 956 | /* |
| 957 | * Copy a cylinder group map. All the unallocated blocks are marked |
| 958 | * BLK_NOCOPY so that the snapshot knows that it need not copy them |
| 959 | * if they are later written. If passno is one, then this is a first |
| 960 | * pass, so only setting needs to be done. If passno is 2, then this |
| 961 | * is a revision to a previous pass which must be undone as the |
| 962 | * replacement pass is done. |
| 963 | */ |
| 964 | static int |
| 965 | cgaccount1(int cg, struct vnode *vp, void *data, int passno) |
| 966 | { |
| 967 | struct buf *bp, *ibp; |
| 968 | struct inode *ip; |
| 969 | struct cg *cgp; |
| 970 | struct fs *fs; |
| 971 | struct lwp *l = curlwp; |
| 972 | daddr_t base, numblks; |
| 973 | int error, len, loc, ns __unused, indiroff; |
| 974 | |
| 975 | ip = VTOI(vp); |
| 976 | fs = ip->i_fs; |
| 977 | ns = UFS_FSNEEDSWAP(fs); |
| 978 | error = bread(ip->i_devvp, FFS_FSBTODB(fs, cgtod(fs, cg)), |
| 979 | (int)fs->fs_cgsize, 0, &bp); |
| 980 | if (error) { |
| 981 | return (error); |
| 982 | } |
| 983 | cgp = (struct cg *)bp->b_data; |
| 984 | if (!cg_chkmagic(cgp, ns)) { |
| 985 | brelse(bp, 0); |
| 986 | return (EIO); |
| 987 | } |
| 988 | ACTIVECG_SET(fs, cg); |
| 989 | |
| 990 | memcpy(data, bp->b_data, fs->fs_cgsize); |
| 991 | brelse(bp, 0); |
| 992 | if (fs->fs_cgsize < fs->fs_bsize) |
| 993 | memset((char *)data + fs->fs_cgsize, 0, |
| 994 | fs->fs_bsize - fs->fs_cgsize); |
| 995 | numblks = howmany(fs->fs_size, fs->fs_frag); |
| 996 | len = howmany(fs->fs_fpg, fs->fs_frag); |
| 997 | base = cg * fs->fs_fpg / fs->fs_frag; |
| 998 | if (base + len >= numblks) |
| 999 | len = numblks - base - 1; |
| 1000 | loc = 0; |
| 1001 | if (base < UFS_NDADDR) { |
| 1002 | for ( ; loc < UFS_NDADDR; loc++) { |
| 1003 | if (ffs_isblock(fs, cg_blksfree(cgp, ns), loc)) |
| 1004 | db_assign(ip, loc, BLK_NOCOPY); |
| 1005 | else if (db_get(ip, loc) == BLK_NOCOPY) { |
| 1006 | if (passno == 2) |
| 1007 | db_assign(ip, loc, 0); |
| 1008 | else if (passno == 1) |
| 1009 | panic("ffs_snapshot: lost direct block" ); |
| 1010 | } |
| 1011 | } |
| 1012 | } |
| 1013 | if ((error = ffs_balloc(vp, ffs_lblktosize(fs, (off_t)(base + loc)), |
| 1014 | fs->fs_bsize, l->l_cred, B_METAONLY, &ibp)) != 0) |
| 1015 | return (error); |
| 1016 | indiroff = (base + loc - UFS_NDADDR) % FFS_NINDIR(fs); |
| 1017 | for ( ; loc < len; loc++, indiroff++) { |
| 1018 | if (indiroff >= FFS_NINDIR(fs)) { |
| 1019 | bawrite(ibp); |
| 1020 | if ((error = ffs_balloc(vp, |
| 1021 | ffs_lblktosize(fs, (off_t)(base + loc)), |
| 1022 | fs->fs_bsize, l->l_cred, B_METAONLY, &ibp)) != 0) |
| 1023 | return (error); |
| 1024 | indiroff = 0; |
| 1025 | } |
| 1026 | if (ffs_isblock(fs, cg_blksfree(cgp, ns), loc)) |
| 1027 | idb_assign(ip, ibp->b_data, indiroff, BLK_NOCOPY); |
| 1028 | else if (idb_get(ip, ibp->b_data, indiroff) == BLK_NOCOPY) { |
| 1029 | if (passno == 2) |
| 1030 | idb_assign(ip, ibp->b_data, indiroff, 0); |
| 1031 | else if (passno == 1) |
| 1032 | panic("ffs_snapshot: lost indirect block" ); |
| 1033 | } |
| 1034 | } |
| 1035 | bdwrite(ibp); |
| 1036 | return (0); |
| 1037 | } |
| 1038 | |
| 1039 | /* |
| 1040 | * Before expunging a snapshot inode, note all the |
| 1041 | * blocks that it claims with BLK_SNAP so that fsck will |
| 1042 | * be able to account for those blocks properly and so |
| 1043 | * that this snapshot knows that it need not copy them |
| 1044 | * if the other snapshot holding them is freed. |
| 1045 | */ |
| 1046 | static int |
| 1047 | expunge(struct vnode *snapvp, struct inode *cancelip, struct fs *fs, |
| 1048 | acctfunc_t acctfunc, int expungetype) |
| 1049 | { |
| 1050 | int i, error, ns __unused; |
| 1051 | daddr_t lbn, rlbn; |
| 1052 | daddr_t len, blkno, numblks, blksperindir; |
| 1053 | struct ufs1_dinode *dip1; |
| 1054 | struct ufs2_dinode *dip2; |
| 1055 | struct lwp *l = curlwp; |
| 1056 | void *bap; |
| 1057 | struct buf *bp; |
| 1058 | struct mount *mp; |
| 1059 | |
| 1060 | ns = UFS_FSNEEDSWAP(fs); |
| 1061 | mp = snapvp->v_mount; |
| 1062 | |
| 1063 | error = UFS_WAPBL_BEGIN(mp); |
| 1064 | if (error) |
| 1065 | return error; |
| 1066 | /* |
| 1067 | * Prepare to expunge the inode. If its inode block has not |
| 1068 | * yet been copied, then allocate and fill the copy. |
| 1069 | */ |
| 1070 | lbn = ffs_fragstoblks(fs, ino_to_fsba(fs, cancelip->i_number)); |
| 1071 | error = snapblkaddr(snapvp, lbn, &blkno); |
| 1072 | if (error) |
| 1073 | return error; |
| 1074 | if (blkno != 0) { |
| 1075 | error = bread(snapvp, lbn, fs->fs_bsize, |
| 1076 | B_MODIFY, &bp); |
| 1077 | } else { |
| 1078 | error = ffs_balloc(snapvp, ffs_lblktosize(fs, (off_t)lbn), |
| 1079 | fs->fs_bsize, l->l_cred, 0, &bp); |
| 1080 | if (! error) |
| 1081 | error = rwfsblk(snapvp, B_READ, bp->b_data, lbn); |
| 1082 | } |
| 1083 | if (error) { |
| 1084 | UFS_WAPBL_END(mp); |
| 1085 | return error; |
| 1086 | } |
| 1087 | /* |
| 1088 | * Set a snapshot inode to be a zero length file, regular files |
| 1089 | * or unlinked snapshots to be completely unallocated. |
| 1090 | */ |
| 1091 | if (fs->fs_magic == FS_UFS1_MAGIC) { |
| 1092 | dip1 = (struct ufs1_dinode *)bp->b_data + |
| 1093 | ino_to_fsbo(fs, cancelip->i_number); |
| 1094 | if (cancelip->i_flags & SF_SNAPSHOT) { |
| 1095 | dip1->di_flags = |
| 1096 | ufs_rw32(ufs_rw32(dip1->di_flags, ns) | |
| 1097 | SF_SNAPINVAL, ns); |
| 1098 | } |
| 1099 | if (expungetype == BLK_NOCOPY || cancelip->i_nlink == 0) |
| 1100 | dip1->di_mode = 0; |
| 1101 | dip1->di_size = 0; |
| 1102 | dip1->di_blocks = 0; |
| 1103 | memset(&dip1->di_db[0], 0, (UFS_NDADDR + UFS_NIADDR) * sizeof(int32_t)); |
| 1104 | } else { |
| 1105 | dip2 = (struct ufs2_dinode *)bp->b_data + |
| 1106 | ino_to_fsbo(fs, cancelip->i_number); |
| 1107 | if (cancelip->i_flags & SF_SNAPSHOT) { |
| 1108 | dip2->di_flags = |
| 1109 | ufs_rw32(ufs_rw32(dip2->di_flags, ns) | |
| 1110 | SF_SNAPINVAL, ns); |
| 1111 | } |
| 1112 | if (expungetype == BLK_NOCOPY || cancelip->i_nlink == 0) |
| 1113 | dip2->di_mode = 0; |
| 1114 | dip2->di_size = 0; |
| 1115 | dip2->di_blocks = 0; |
| 1116 | memset(&dip2->di_db[0], 0, (UFS_NDADDR + UFS_NIADDR) * sizeof(int64_t)); |
| 1117 | } |
| 1118 | bdwrite(bp); |
| 1119 | UFS_WAPBL_END(mp); |
| 1120 | /* |
| 1121 | * Now go through and expunge all the blocks in the file |
| 1122 | * using the function requested. |
| 1123 | */ |
| 1124 | numblks = howmany(cancelip->i_size, fs->fs_bsize); |
| 1125 | if (fs->fs_magic == FS_UFS1_MAGIC) |
| 1126 | bap = &cancelip->i_ffs1_db[0]; |
| 1127 | else |
| 1128 | bap = &cancelip->i_ffs2_db[0]; |
| 1129 | error = (*acctfunc)(snapvp, bap, 0, UFS_NDADDR, fs, 0, expungetype); |
| 1130 | if (error) |
| 1131 | return (error); |
| 1132 | if (fs->fs_magic == FS_UFS1_MAGIC) |
| 1133 | bap = &cancelip->i_ffs1_ib[0]; |
| 1134 | else |
| 1135 | bap = &cancelip->i_ffs2_ib[0]; |
| 1136 | error = (*acctfunc)(snapvp, bap, 0, UFS_NIADDR, fs, -1, expungetype); |
| 1137 | if (error) |
| 1138 | return (error); |
| 1139 | blksperindir = 1; |
| 1140 | lbn = -UFS_NDADDR; |
| 1141 | len = numblks - UFS_NDADDR; |
| 1142 | rlbn = UFS_NDADDR; |
| 1143 | for (i = 0; len > 0 && i < UFS_NIADDR; i++) { |
| 1144 | error = indiracct(snapvp, ITOV(cancelip), i, |
| 1145 | ib_get(cancelip, i), lbn, rlbn, len, |
| 1146 | blksperindir, fs, acctfunc, expungetype); |
| 1147 | if (error) |
| 1148 | return (error); |
| 1149 | blksperindir *= FFS_NINDIR(fs); |
| 1150 | lbn -= blksperindir + 1; |
| 1151 | len -= blksperindir; |
| 1152 | rlbn += blksperindir; |
| 1153 | } |
| 1154 | return (0); |
| 1155 | } |
| 1156 | |
| 1157 | /* |
| 1158 | * Descend an indirect block chain for vnode cancelvp accounting for all |
| 1159 | * its indirect blocks in snapvp. |
| 1160 | */ |
| 1161 | static int |
| 1162 | indiracct(struct vnode *snapvp, struct vnode *cancelvp, int level, |
| 1163 | daddr_t blkno, daddr_t lbn, daddr_t rlbn, daddr_t remblks, |
| 1164 | daddr_t blksperindir, struct fs *fs, acctfunc_t acctfunc, int expungetype) |
| 1165 | { |
| 1166 | int error, num, i; |
| 1167 | daddr_t subblksperindir; |
| 1168 | struct indir indirs[UFS_NIADDR + 2]; |
| 1169 | daddr_t last; |
| 1170 | void *bap; |
| 1171 | struct buf *bp; |
| 1172 | |
| 1173 | if (blkno == 0) { |
| 1174 | if (expungetype == BLK_NOCOPY) |
| 1175 | return (0); |
| 1176 | panic("indiracct: missing indir" ); |
| 1177 | } |
| 1178 | if ((error = ufs_getlbns(cancelvp, rlbn, indirs, &num)) != 0) |
| 1179 | return (error); |
| 1180 | if (lbn != indirs[num - 1 - level].in_lbn || num < 2) |
| 1181 | panic("indiracct: botched params" ); |
| 1182 | /* |
| 1183 | * We have to expand bread here since it will deadlock looking |
| 1184 | * up the block number for any blocks that are not in the cache. |
| 1185 | */ |
| 1186 | error = ffs_getblk(cancelvp, lbn, FFS_FSBTODB(fs, blkno), fs->fs_bsize, |
| 1187 | false, &bp); |
| 1188 | if (error) |
| 1189 | return error; |
| 1190 | if ((bp->b_oflags & (BO_DONE | BO_DELWRI)) == 0 && (error = |
| 1191 | rwfsblk(bp->b_vp, B_READ, bp->b_data, ffs_fragstoblks(fs, blkno)))) { |
| 1192 | brelse(bp, 0); |
| 1193 | return (error); |
| 1194 | } |
| 1195 | /* |
| 1196 | * Account for the block pointers in this indirect block. |
| 1197 | */ |
| 1198 | last = howmany(remblks, blksperindir); |
| 1199 | if (last > FFS_NINDIR(fs)) |
| 1200 | last = FFS_NINDIR(fs); |
| 1201 | bap = malloc(fs->fs_bsize, M_DEVBUF, M_WAITOK | M_ZERO); |
| 1202 | memcpy((void *)bap, bp->b_data, fs->fs_bsize); |
| 1203 | brelse(bp, 0); |
| 1204 | error = (*acctfunc)(snapvp, bap, 0, last, |
| 1205 | fs, level == 0 ? rlbn : -1, expungetype); |
| 1206 | if (error || level == 0) |
| 1207 | goto out; |
| 1208 | /* |
| 1209 | * Account for the block pointers in each of the indirect blocks |
| 1210 | * in the levels below us. |
| 1211 | */ |
| 1212 | subblksperindir = blksperindir / FFS_NINDIR(fs); |
| 1213 | for (lbn++, level--, i = 0; i < last; i++) { |
| 1214 | error = indiracct(snapvp, cancelvp, level, |
| 1215 | idb_get(VTOI(snapvp), bap, i), lbn, rlbn, remblks, |
| 1216 | subblksperindir, fs, acctfunc, expungetype); |
| 1217 | if (error) |
| 1218 | goto out; |
| 1219 | rlbn += blksperindir; |
| 1220 | lbn -= blksperindir; |
| 1221 | remblks -= blksperindir; |
| 1222 | } |
| 1223 | out: |
| 1224 | free(bap, M_DEVBUF); |
| 1225 | return (error); |
| 1226 | } |
| 1227 | |
| 1228 | /* |
| 1229 | * Do both snap accounting and map accounting. |
| 1230 | */ |
| 1231 | static int |
| 1232 | fullacct(struct vnode *vp, void *bap, int oldblkp, int lastblkp, |
| 1233 | struct fs *fs, daddr_t lblkno, |
| 1234 | int exptype /* BLK_SNAP or BLK_NOCOPY */) |
| 1235 | { |
| 1236 | int error; |
| 1237 | |
| 1238 | if ((error = snapacct(vp, bap, oldblkp, lastblkp, fs, lblkno, exptype))) |
| 1239 | return (error); |
| 1240 | return (mapacct(vp, bap, oldblkp, lastblkp, fs, lblkno, exptype)); |
| 1241 | } |
| 1242 | |
| 1243 | /* |
| 1244 | * Identify a set of blocks allocated in a snapshot inode. |
| 1245 | */ |
| 1246 | static int |
| 1247 | snapacct(struct vnode *vp, void *bap, int oldblkp, int lastblkp, |
| 1248 | struct fs *fs, daddr_t lblkno, |
| 1249 | int expungetype /* BLK_SNAP or BLK_NOCOPY */) |
| 1250 | { |
| 1251 | struct inode *ip = VTOI(vp); |
| 1252 | struct lwp *l = curlwp; |
| 1253 | struct mount *mp = vp->v_mount; |
| 1254 | daddr_t blkno; |
| 1255 | daddr_t lbn; |
| 1256 | struct buf *ibp; |
| 1257 | int error, n; |
| 1258 | const int wbreak = blocks_in_journal(VFSTOUFS(mp)->um_fs)/8; |
| 1259 | |
| 1260 | error = UFS_WAPBL_BEGIN(mp); |
| 1261 | if (error) |
| 1262 | return error; |
| 1263 | for ( n = 0; oldblkp < lastblkp; oldblkp++) { |
| 1264 | blkno = idb_get(ip, bap, oldblkp); |
| 1265 | if (blkno == 0 || blkno == BLK_NOCOPY || blkno == BLK_SNAP) |
| 1266 | continue; |
| 1267 | lbn = ffs_fragstoblks(fs, blkno); |
| 1268 | if (lbn < UFS_NDADDR) { |
| 1269 | blkno = db_get(ip, lbn); |
| 1270 | ip->i_flag |= IN_CHANGE | IN_UPDATE; |
| 1271 | } else { |
| 1272 | error = ffs_balloc(vp, ffs_lblktosize(fs, (off_t)lbn), |
| 1273 | fs->fs_bsize, l->l_cred, B_METAONLY, &ibp); |
| 1274 | if (error) |
| 1275 | break; |
| 1276 | blkno = idb_get(ip, ibp->b_data, |
| 1277 | (lbn - UFS_NDADDR) % FFS_NINDIR(fs)); |
| 1278 | } |
| 1279 | /* |
| 1280 | * If we are expunging a snapshot vnode and we |
| 1281 | * find a block marked BLK_NOCOPY, then it is |
| 1282 | * one that has been allocated to this snapshot after |
| 1283 | * we took our current snapshot and can be ignored. |
| 1284 | */ |
| 1285 | if (expungetype == BLK_SNAP && blkno == BLK_NOCOPY) { |
| 1286 | if (lbn >= UFS_NDADDR) |
| 1287 | brelse(ibp, 0); |
| 1288 | } else { |
| 1289 | if (blkno != 0) |
| 1290 | panic("snapacct: bad block" ); |
| 1291 | if (lbn < UFS_NDADDR) |
| 1292 | db_assign(ip, lbn, expungetype); |
| 1293 | else { |
| 1294 | idb_assign(ip, ibp->b_data, |
| 1295 | (lbn - UFS_NDADDR) % FFS_NINDIR(fs), expungetype); |
| 1296 | bdwrite(ibp); |
| 1297 | } |
| 1298 | } |
| 1299 | if (wbreak > 0 && (++n % wbreak) == 0) { |
| 1300 | UFS_WAPBL_END(mp); |
| 1301 | error = UFS_WAPBL_BEGIN(mp); |
| 1302 | if (error) |
| 1303 | return error; |
| 1304 | } |
| 1305 | } |
| 1306 | UFS_WAPBL_END(mp); |
| 1307 | return error; |
| 1308 | } |
| 1309 | |
| 1310 | /* |
| 1311 | * Account for a set of blocks allocated in a snapshot inode. |
| 1312 | */ |
| 1313 | static int |
| 1314 | mapacct(struct vnode *vp, void *bap, int oldblkp, int lastblkp, |
| 1315 | struct fs *fs, daddr_t lblkno, int expungetype) |
| 1316 | { |
| 1317 | daddr_t blkno; |
| 1318 | struct inode *ip; |
| 1319 | struct mount *mp = vp->v_mount; |
| 1320 | ino_t inum; |
| 1321 | int acctit, error, n; |
| 1322 | const int wbreak = blocks_in_journal(VFSTOUFS(mp)->um_fs)/8; |
| 1323 | |
| 1324 | error = UFS_WAPBL_BEGIN(mp); |
| 1325 | if (error) |
| 1326 | return error; |
| 1327 | ip = VTOI(vp); |
| 1328 | inum = ip->i_number; |
| 1329 | if (lblkno == -1) |
| 1330 | acctit = 0; |
| 1331 | else |
| 1332 | acctit = 1; |
| 1333 | for ( n = 0; oldblkp < lastblkp; oldblkp++, lblkno++) { |
| 1334 | blkno = idb_get(ip, bap, oldblkp); |
| 1335 | if (blkno == 0 || blkno == BLK_NOCOPY) |
| 1336 | continue; |
| 1337 | if (acctit && expungetype == BLK_SNAP && blkno != BLK_SNAP) |
| 1338 | *ip->i_snapblklist++ = lblkno; |
| 1339 | if (blkno == BLK_SNAP) |
| 1340 | blkno = ffs_blkstofrags(fs, lblkno); |
| 1341 | ffs_blkfree_snap(fs, vp, blkno, fs->fs_bsize, inum); |
| 1342 | if (wbreak > 0 && (++n % wbreak) == 0) { |
| 1343 | UFS_WAPBL_END(mp); |
| 1344 | error = UFS_WAPBL_BEGIN(mp); |
| 1345 | if (error) |
| 1346 | return error; |
| 1347 | } |
| 1348 | } |
| 1349 | UFS_WAPBL_END(mp); |
| 1350 | return (0); |
| 1351 | } |
| 1352 | |
| 1353 | /* |
| 1354 | * Number of blocks that fit into the journal or zero if not logging. |
| 1355 | */ |
| 1356 | static int |
| 1357 | blocks_in_journal(struct fs *fs) |
| 1358 | { |
| 1359 | off_t bpj; |
| 1360 | |
| 1361 | if ((fs->fs_flags & FS_DOWAPBL) == 0) |
| 1362 | return 0; |
| 1363 | bpj = 1; |
| 1364 | if (fs->fs_journal_version == UFS_WAPBL_VERSION) { |
| 1365 | switch (fs->fs_journal_location) { |
| 1366 | case UFS_WAPBL_JOURNALLOC_END_PARTITION: |
| 1367 | bpj = (off_t)fs->fs_journallocs[UFS_WAPBL_EPART_BLKSZ]* |
| 1368 | fs->fs_journallocs[UFS_WAPBL_EPART_COUNT]; |
| 1369 | break; |
| 1370 | case UFS_WAPBL_JOURNALLOC_IN_FILESYSTEM: |
| 1371 | bpj = (off_t)fs->fs_journallocs[UFS_WAPBL_INFS_BLKSZ]* |
| 1372 | fs->fs_journallocs[UFS_WAPBL_INFS_COUNT]; |
| 1373 | break; |
| 1374 | } |
| 1375 | } |
| 1376 | bpj /= fs->fs_bsize; |
| 1377 | return (bpj > 0 ? bpj : 1); |
| 1378 | } |
| 1379 | #endif /* defined(FFS_NO_SNAPSHOT) */ |
| 1380 | |
| 1381 | /* |
| 1382 | * Decrement extra reference on snapshot when last name is removed. |
| 1383 | * It will not be freed until the last open reference goes away. |
| 1384 | */ |
| 1385 | void |
| 1386 | ffs_snapgone(struct vnode *vp) |
| 1387 | { |
| 1388 | struct inode *xp, *ip = VTOI(vp); |
| 1389 | struct mount *mp = spec_node_getmountedfs(ip->i_devvp); |
| 1390 | struct fs *fs; |
| 1391 | struct snap_info *si; |
| 1392 | int snaploc; |
| 1393 | |
| 1394 | si = VFSTOUFS(mp)->um_snapinfo; |
| 1395 | |
| 1396 | /* |
| 1397 | * Find snapshot in incore list. |
| 1398 | */ |
| 1399 | mutex_enter(&si->si_lock); |
| 1400 | TAILQ_FOREACH(xp, &si->si_snapshots, i_nextsnap) |
| 1401 | if (xp == ip) |
| 1402 | break; |
| 1403 | mutex_exit(&si->si_lock); |
| 1404 | if (xp != NULL) |
| 1405 | vrele(ITOV(ip)); |
| 1406 | #ifdef DEBUG |
| 1407 | else if (snapdebug) |
| 1408 | printf("ffs_snapgone: lost snapshot vnode %llu\n" , |
| 1409 | (unsigned long long)ip->i_number); |
| 1410 | #endif |
| 1411 | /* |
| 1412 | * Delete snapshot inode from superblock. Keep list dense. |
| 1413 | */ |
| 1414 | mutex_enter(&si->si_lock); |
| 1415 | fs = ip->i_fs; |
| 1416 | for (snaploc = 0; snaploc < FSMAXSNAP; snaploc++) |
| 1417 | if (fs->fs_snapinum[snaploc] == ip->i_number) |
| 1418 | break; |
| 1419 | if (snaploc < FSMAXSNAP) { |
| 1420 | for (snaploc++; snaploc < FSMAXSNAP; snaploc++) { |
| 1421 | if (fs->fs_snapinum[snaploc] == 0) |
| 1422 | break; |
| 1423 | fs->fs_snapinum[snaploc - 1] = fs->fs_snapinum[snaploc]; |
| 1424 | } |
| 1425 | fs->fs_snapinum[snaploc - 1] = 0; |
| 1426 | } |
| 1427 | si->si_gen++; |
| 1428 | mutex_exit(&si->si_lock); |
| 1429 | } |
| 1430 | |
| 1431 | /* |
| 1432 | * Prepare a snapshot file for being removed. |
| 1433 | */ |
| 1434 | void |
| 1435 | ffs_snapremove(struct vnode *vp) |
| 1436 | { |
| 1437 | struct inode *ip = VTOI(vp), *xp; |
| 1438 | struct vnode *devvp = ip->i_devvp; |
| 1439 | struct fs *fs = ip->i_fs; |
| 1440 | struct mount *mp = spec_node_getmountedfs(devvp); |
| 1441 | struct buf *ibp; |
| 1442 | struct snap_info *si; |
| 1443 | struct lwp *l = curlwp; |
| 1444 | daddr_t numblks, blkno, dblk; |
| 1445 | int error, loc, last; |
| 1446 | |
| 1447 | si = VFSTOUFS(mp)->um_snapinfo; |
| 1448 | /* |
| 1449 | * If active, delete from incore list (this snapshot may |
| 1450 | * already have been in the process of being deleted, so |
| 1451 | * would not have been active). |
| 1452 | * |
| 1453 | * Clear copy-on-write flag if last snapshot. |
| 1454 | */ |
| 1455 | mutex_enter(&si->si_snaplock); |
| 1456 | mutex_enter(&si->si_lock); |
| 1457 | if (is_active_snapshot(si, ip)) { |
| 1458 | TAILQ_REMOVE(&si->si_snapshots, ip, i_nextsnap); |
| 1459 | if (TAILQ_FIRST(&si->si_snapshots) != 0) { |
| 1460 | /* Roll back the list of preallocated blocks. */ |
| 1461 | xp = TAILQ_LAST(&si->si_snapshots, inodelst); |
| 1462 | si->si_snapblklist = xp->i_snapblklist; |
| 1463 | si->si_gen++; |
| 1464 | mutex_exit(&si->si_lock); |
| 1465 | mutex_exit(&si->si_snaplock); |
| 1466 | } else { |
| 1467 | si->si_snapblklist = 0; |
| 1468 | si->si_gen++; |
| 1469 | mutex_exit(&si->si_lock); |
| 1470 | mutex_exit(&si->si_snaplock); |
| 1471 | fscow_disestablish(mp, ffs_copyonwrite, devvp); |
| 1472 | } |
| 1473 | if (ip->i_snapblklist != NULL) { |
| 1474 | free(ip->i_snapblklist, M_UFSMNT); |
| 1475 | ip->i_snapblklist = NULL; |
| 1476 | } |
| 1477 | } else { |
| 1478 | mutex_exit(&si->si_lock); |
| 1479 | mutex_exit(&si->si_snaplock); |
| 1480 | } |
| 1481 | /* |
| 1482 | * Clear all BLK_NOCOPY fields. Pass any block claims to other |
| 1483 | * snapshots that want them (see ffs_snapblkfree below). |
| 1484 | */ |
| 1485 | for (blkno = 1; blkno < UFS_NDADDR; blkno++) { |
| 1486 | dblk = db_get(ip, blkno); |
| 1487 | if (dblk == BLK_NOCOPY || dblk == BLK_SNAP) |
| 1488 | db_assign(ip, blkno, 0); |
| 1489 | else if ((dblk == ffs_blkstofrags(fs, blkno) && |
| 1490 | ffs_snapblkfree(fs, ip->i_devvp, dblk, fs->fs_bsize, |
| 1491 | ip->i_number))) { |
| 1492 | DIP_ADD(ip, blocks, -btodb(fs->fs_bsize)); |
| 1493 | db_assign(ip, blkno, 0); |
| 1494 | } |
| 1495 | } |
| 1496 | numblks = howmany(ip->i_size, fs->fs_bsize); |
| 1497 | for (blkno = UFS_NDADDR; blkno < numblks; blkno += FFS_NINDIR(fs)) { |
| 1498 | error = ffs_balloc(vp, ffs_lblktosize(fs, (off_t)blkno), |
| 1499 | fs->fs_bsize, l->l_cred, B_METAONLY, &ibp); |
| 1500 | if (error) |
| 1501 | continue; |
| 1502 | if (fs->fs_size - blkno > FFS_NINDIR(fs)) |
| 1503 | last = FFS_NINDIR(fs); |
| 1504 | else |
| 1505 | last = fs->fs_size - blkno; |
| 1506 | for (loc = 0; loc < last; loc++) { |
| 1507 | dblk = idb_get(ip, ibp->b_data, loc); |
| 1508 | if (dblk == BLK_NOCOPY || dblk == BLK_SNAP) |
| 1509 | idb_assign(ip, ibp->b_data, loc, 0); |
| 1510 | else if (dblk == ffs_blkstofrags(fs, blkno) && |
| 1511 | ffs_snapblkfree(fs, ip->i_devvp, dblk, |
| 1512 | fs->fs_bsize, ip->i_number)) { |
| 1513 | DIP_ADD(ip, blocks, -btodb(fs->fs_bsize)); |
| 1514 | idb_assign(ip, ibp->b_data, loc, 0); |
| 1515 | } |
| 1516 | } |
| 1517 | bawrite(ibp); |
| 1518 | UFS_WAPBL_END(mp); |
| 1519 | error = UFS_WAPBL_BEGIN(mp); |
| 1520 | KASSERT(error == 0); |
| 1521 | } |
| 1522 | /* |
| 1523 | * Clear snapshot flag and drop reference. |
| 1524 | */ |
| 1525 | ip->i_flags &= ~(SF_SNAPSHOT | SF_SNAPINVAL); |
| 1526 | DIP_ASSIGN(ip, flags, ip->i_flags); |
| 1527 | ip->i_flag |= IN_CHANGE | IN_UPDATE; |
| 1528 | #if defined(QUOTA) || defined(QUOTA2) |
| 1529 | chkdq(ip, DIP(ip, blocks), l->l_cred, FORCE); |
| 1530 | chkiq(ip, 1, l->l_cred, FORCE); |
| 1531 | #endif |
| 1532 | } |
| 1533 | |
| 1534 | /* |
| 1535 | * Notification that a block is being freed. Return zero if the free |
| 1536 | * should be allowed to proceed. Return non-zero if the snapshot file |
| 1537 | * wants to claim the block. The block will be claimed if it is an |
| 1538 | * uncopied part of one of the snapshots. It will be freed if it is |
| 1539 | * either a BLK_NOCOPY or has already been copied in all of the snapshots. |
| 1540 | * If a fragment is being freed, then all snapshots that care about |
| 1541 | * it must make a copy since a snapshot file can only claim full sized |
| 1542 | * blocks. Note that if more than one snapshot file maps the block, |
| 1543 | * we can pick one at random to claim it. Since none of the snapshots |
| 1544 | * can change, we are assurred that they will all see the same unmodified |
| 1545 | * image. When deleting a snapshot file (see ffs_snapremove above), we |
| 1546 | * must push any of these claimed blocks to one of the other snapshots |
| 1547 | * that maps it. These claimed blocks are easily identified as they will |
| 1548 | * have a block number equal to their logical block number within the |
| 1549 | * snapshot. A copied block can never have this property because they |
| 1550 | * must always have been allocated from a BLK_NOCOPY location. |
| 1551 | */ |
| 1552 | int |
| 1553 | ffs_snapblkfree(struct fs *fs, struct vnode *devvp, daddr_t bno, |
| 1554 | long size, ino_t inum) |
| 1555 | { |
| 1556 | struct mount *mp = spec_node_getmountedfs(devvp); |
| 1557 | struct buf *ibp; |
| 1558 | struct inode *ip; |
| 1559 | struct vnode *vp = NULL; |
| 1560 | struct snap_info *si; |
| 1561 | void *saved_data = NULL; |
| 1562 | daddr_t lbn; |
| 1563 | daddr_t blkno; |
| 1564 | uint32_t gen; |
| 1565 | int indiroff = 0, error = 0, claimedblk = 0; |
| 1566 | |
| 1567 | si = VFSTOUFS(mp)->um_snapinfo; |
| 1568 | lbn = ffs_fragstoblks(fs, bno); |
| 1569 | mutex_enter(&si->si_snaplock); |
| 1570 | mutex_enter(&si->si_lock); |
| 1571 | si->si_owner = curlwp; |
| 1572 | |
| 1573 | retry: |
| 1574 | gen = si->si_gen; |
| 1575 | TAILQ_FOREACH(ip, &si->si_snapshots, i_nextsnap) { |
| 1576 | vp = ITOV(ip); |
| 1577 | /* |
| 1578 | * Lookup block being written. |
| 1579 | */ |
| 1580 | if (lbn < UFS_NDADDR) { |
| 1581 | blkno = db_get(ip, lbn); |
| 1582 | } else { |
| 1583 | mutex_exit(&si->si_lock); |
| 1584 | error = ffs_balloc(vp, ffs_lblktosize(fs, (off_t)lbn), |
| 1585 | fs->fs_bsize, FSCRED, B_METAONLY, &ibp); |
| 1586 | if (error) { |
| 1587 | mutex_enter(&si->si_lock); |
| 1588 | break; |
| 1589 | } |
| 1590 | indiroff = (lbn - UFS_NDADDR) % FFS_NINDIR(fs); |
| 1591 | blkno = idb_get(ip, ibp->b_data, indiroff); |
| 1592 | mutex_enter(&si->si_lock); |
| 1593 | if (gen != si->si_gen) { |
| 1594 | brelse(ibp, 0); |
| 1595 | goto retry; |
| 1596 | } |
| 1597 | } |
| 1598 | /* |
| 1599 | * Check to see if block needs to be copied. |
| 1600 | */ |
| 1601 | if (blkno == 0) { |
| 1602 | /* |
| 1603 | * A block that we map is being freed. If it has not |
| 1604 | * been claimed yet, we will claim or copy it (below). |
| 1605 | */ |
| 1606 | claimedblk = 1; |
| 1607 | } else if (blkno == BLK_SNAP) { |
| 1608 | /* |
| 1609 | * No previous snapshot claimed the block, |
| 1610 | * so it will be freed and become a BLK_NOCOPY |
| 1611 | * (don't care) for us. |
| 1612 | */ |
| 1613 | if (claimedblk) |
| 1614 | panic("snapblkfree: inconsistent block type" ); |
| 1615 | if (lbn < UFS_NDADDR) { |
| 1616 | db_assign(ip, lbn, BLK_NOCOPY); |
| 1617 | ip->i_flag |= IN_CHANGE | IN_UPDATE; |
| 1618 | } else { |
| 1619 | idb_assign(ip, ibp->b_data, indiroff, |
| 1620 | BLK_NOCOPY); |
| 1621 | mutex_exit(&si->si_lock); |
| 1622 | if (ip->i_nlink > 0) |
| 1623 | bwrite(ibp); |
| 1624 | else |
| 1625 | bdwrite(ibp); |
| 1626 | mutex_enter(&si->si_lock); |
| 1627 | if (gen != si->si_gen) |
| 1628 | goto retry; |
| 1629 | } |
| 1630 | continue; |
| 1631 | } else /* BLK_NOCOPY or default */ { |
| 1632 | /* |
| 1633 | * If the snapshot has already copied the block |
| 1634 | * (default), or does not care about the block, |
| 1635 | * it is not needed. |
| 1636 | */ |
| 1637 | if (lbn >= UFS_NDADDR) |
| 1638 | brelse(ibp, 0); |
| 1639 | continue; |
| 1640 | } |
| 1641 | /* |
| 1642 | * If this is a full size block, we will just grab it |
| 1643 | * and assign it to the snapshot inode. Otherwise we |
| 1644 | * will proceed to copy it. See explanation for this |
| 1645 | * routine as to why only a single snapshot needs to |
| 1646 | * claim this block. |
| 1647 | */ |
| 1648 | if (size == fs->fs_bsize) { |
| 1649 | #ifdef DEBUG |
| 1650 | if (snapdebug) |
| 1651 | printf("%s %llu lbn %" PRId64 |
| 1652 | "from inum %llu\n" , |
| 1653 | "Grabonremove: snapino" , |
| 1654 | (unsigned long long)ip->i_number, |
| 1655 | lbn, (unsigned long long)inum); |
| 1656 | #endif |
| 1657 | mutex_exit(&si->si_lock); |
| 1658 | if (lbn < UFS_NDADDR) { |
| 1659 | db_assign(ip, lbn, bno); |
| 1660 | } else { |
| 1661 | idb_assign(ip, ibp->b_data, indiroff, bno); |
| 1662 | if (ip->i_nlink > 0) |
| 1663 | bwrite(ibp); |
| 1664 | else |
| 1665 | bdwrite(ibp); |
| 1666 | } |
| 1667 | DIP_ADD(ip, blocks, btodb(size)); |
| 1668 | ip->i_flag |= IN_CHANGE | IN_UPDATE; |
| 1669 | if (ip->i_nlink > 0 && mp->mnt_wapbl) |
| 1670 | error = syncsnap(vp); |
| 1671 | else |
| 1672 | error = 0; |
| 1673 | mutex_enter(&si->si_lock); |
| 1674 | si->si_owner = NULL; |
| 1675 | mutex_exit(&si->si_lock); |
| 1676 | mutex_exit(&si->si_snaplock); |
| 1677 | return (error == 0); |
| 1678 | } |
| 1679 | if (lbn >= UFS_NDADDR) |
| 1680 | brelse(ibp, 0); |
| 1681 | #ifdef DEBUG |
| 1682 | if (snapdebug) |
| 1683 | printf("%s%llu lbn %" PRId64 " %s %llu size %ld\n" , |
| 1684 | "Copyonremove: snapino " , |
| 1685 | (unsigned long long)ip->i_number, |
| 1686 | lbn, "for inum" , (unsigned long long)inum, size); |
| 1687 | #endif |
| 1688 | /* |
| 1689 | * If we have already read the old block contents, then |
| 1690 | * simply copy them to the new block. Note that we need |
| 1691 | * to synchronously write snapshots that have not been |
| 1692 | * unlinked, and hence will be visible after a crash, |
| 1693 | * to ensure their integrity. |
| 1694 | */ |
| 1695 | mutex_exit(&si->si_lock); |
| 1696 | if (saved_data == NULL) { |
| 1697 | saved_data = malloc(fs->fs_bsize, M_UFSMNT, M_WAITOK); |
| 1698 | error = rwfsblk(vp, B_READ, saved_data, lbn); |
| 1699 | if (error) { |
| 1700 | free(saved_data, M_UFSMNT); |
| 1701 | saved_data = NULL; |
| 1702 | mutex_enter(&si->si_lock); |
| 1703 | break; |
| 1704 | } |
| 1705 | } |
| 1706 | error = wrsnapblk(vp, saved_data, lbn); |
| 1707 | if (error == 0 && ip->i_nlink > 0 && mp->mnt_wapbl) |
| 1708 | error = syncsnap(vp); |
| 1709 | mutex_enter(&si->si_lock); |
| 1710 | if (error) |
| 1711 | break; |
| 1712 | if (gen != si->si_gen) |
| 1713 | goto retry; |
| 1714 | } |
| 1715 | si->si_owner = NULL; |
| 1716 | mutex_exit(&si->si_lock); |
| 1717 | mutex_exit(&si->si_snaplock); |
| 1718 | if (saved_data) |
| 1719 | free(saved_data, M_UFSMNT); |
| 1720 | /* |
| 1721 | * If we have been unable to allocate a block in which to do |
| 1722 | * the copy, then return non-zero so that the fragment will |
| 1723 | * not be freed. Although space will be lost, the snapshot |
| 1724 | * will stay consistent. |
| 1725 | */ |
| 1726 | return (error); |
| 1727 | } |
| 1728 | |
| 1729 | /* |
| 1730 | * Associate snapshot files when mounting. |
| 1731 | */ |
| 1732 | void |
| 1733 | ffs_snapshot_mount(struct mount *mp) |
| 1734 | { |
| 1735 | struct vnode *devvp = VFSTOUFS(mp)->um_devvp; |
| 1736 | struct fs *fs = VFSTOUFS(mp)->um_fs; |
| 1737 | struct lwp *l = curlwp; |
| 1738 | struct vnode *vp; |
| 1739 | struct inode *ip, *xp; |
| 1740 | struct snap_info *si; |
| 1741 | daddr_t snaplistsize, *snapblklist; |
| 1742 | int i, error, ns __unused, snaploc, loc; |
| 1743 | |
| 1744 | /* |
| 1745 | * No persistent snapshots on apple ufs file systems. |
| 1746 | */ |
| 1747 | if (UFS_MPISAPPLEUFS(VFSTOUFS(mp))) |
| 1748 | return; |
| 1749 | |
| 1750 | si = VFSTOUFS(mp)->um_snapinfo; |
| 1751 | ns = UFS_FSNEEDSWAP(fs); |
| 1752 | /* |
| 1753 | * XXX The following needs to be set before ffs_truncate or |
| 1754 | * VOP_READ can be called. |
| 1755 | */ |
| 1756 | mp->mnt_stat.f_iosize = fs->fs_bsize; |
| 1757 | /* |
| 1758 | * Process each snapshot listed in the superblock. |
| 1759 | */ |
| 1760 | vp = NULL; |
| 1761 | mutex_enter(&si->si_lock); |
| 1762 | for (snaploc = 0; snaploc < FSMAXSNAP; snaploc++) { |
| 1763 | if (fs->fs_snapinum[snaploc] == 0) |
| 1764 | break; |
| 1765 | if ((error = VFS_VGET(mp, fs->fs_snapinum[snaploc], |
| 1766 | &vp)) != 0) { |
| 1767 | printf("ffs_snapshot_mount: vget failed %d\n" , error); |
| 1768 | continue; |
| 1769 | } |
| 1770 | ip = VTOI(vp); |
| 1771 | if ((ip->i_flags & (SF_SNAPSHOT | SF_SNAPINVAL)) != |
| 1772 | SF_SNAPSHOT) { |
| 1773 | printf("ffs_snapshot_mount: non-snapshot inode %d\n" , |
| 1774 | fs->fs_snapinum[snaploc]); |
| 1775 | vput(vp); |
| 1776 | vp = NULL; |
| 1777 | for (loc = snaploc + 1; loc < FSMAXSNAP; loc++) { |
| 1778 | if (fs->fs_snapinum[loc] == 0) |
| 1779 | break; |
| 1780 | fs->fs_snapinum[loc - 1] = fs->fs_snapinum[loc]; |
| 1781 | } |
| 1782 | fs->fs_snapinum[loc - 1] = 0; |
| 1783 | snaploc--; |
| 1784 | continue; |
| 1785 | } |
| 1786 | |
| 1787 | /* |
| 1788 | * Read the block hints list. Use an empty list on |
| 1789 | * read errors. |
| 1790 | */ |
| 1791 | error = vn_rdwr(UIO_READ, vp, |
| 1792 | (void *)&snaplistsize, sizeof(snaplistsize), |
| 1793 | ffs_lblktosize(fs, howmany(fs->fs_size, fs->fs_frag)), |
| 1794 | UIO_SYSSPACE, IO_NODELOCKED|IO_UNIT|IO_ALTSEMANTICS, |
| 1795 | l->l_cred, NULL, NULL); |
| 1796 | if (error) { |
| 1797 | printf("ffs_snapshot_mount: read_1 failed %d\n" , error); |
| 1798 | snaplistsize = 1; |
| 1799 | } else |
| 1800 | snaplistsize = ufs_rw64(snaplistsize, ns); |
| 1801 | snapblklist = malloc( |
| 1802 | snaplistsize * sizeof(daddr_t), M_UFSMNT, M_WAITOK); |
| 1803 | if (error) |
| 1804 | snapblklist[0] = 1; |
| 1805 | else { |
| 1806 | error = vn_rdwr(UIO_READ, vp, (void *)snapblklist, |
| 1807 | snaplistsize * sizeof(daddr_t), |
| 1808 | ffs_lblktosize(fs, howmany(fs->fs_size, fs->fs_frag)), |
| 1809 | UIO_SYSSPACE, IO_NODELOCKED|IO_UNIT|IO_ALTSEMANTICS, |
| 1810 | l->l_cred, NULL, NULL); |
| 1811 | for (i = 0; i < snaplistsize; i++) |
| 1812 | snapblklist[i] = ufs_rw64(snapblklist[i], ns); |
| 1813 | if (error) { |
| 1814 | printf("ffs_snapshot_mount: read_2 failed %d\n" , |
| 1815 | error); |
| 1816 | snapblklist[0] = 1; |
| 1817 | } |
| 1818 | } |
| 1819 | ip->i_snapblklist = &snapblklist[0]; |
| 1820 | |
| 1821 | /* |
| 1822 | * Link it onto the active snapshot list. |
| 1823 | */ |
| 1824 | if (is_active_snapshot(si, ip)) |
| 1825 | panic("ffs_snapshot_mount: %" PRIu64" already on list" , |
| 1826 | ip->i_number); |
| 1827 | else |
| 1828 | TAILQ_INSERT_TAIL(&si->si_snapshots, ip, i_nextsnap); |
| 1829 | vp->v_vflag |= VV_SYSTEM; |
| 1830 | VOP_UNLOCK(vp); |
| 1831 | } |
| 1832 | /* |
| 1833 | * No usable snapshots found. |
| 1834 | */ |
| 1835 | if (vp == NULL) { |
| 1836 | mutex_exit(&si->si_lock); |
| 1837 | return; |
| 1838 | } |
| 1839 | /* |
| 1840 | * Attach the block hints list. We always want to |
| 1841 | * use the list from the newest snapshot. |
| 1842 | */ |
| 1843 | xp = TAILQ_LAST(&si->si_snapshots, inodelst); |
| 1844 | si->si_snapblklist = xp->i_snapblklist; |
| 1845 | fscow_establish(mp, ffs_copyonwrite, devvp); |
| 1846 | si->si_gen++; |
| 1847 | mutex_exit(&si->si_lock); |
| 1848 | } |
| 1849 | |
| 1850 | /* |
| 1851 | * Disassociate snapshot files when unmounting. |
| 1852 | */ |
| 1853 | void |
| 1854 | ffs_snapshot_unmount(struct mount *mp) |
| 1855 | { |
| 1856 | struct vnode *devvp = VFSTOUFS(mp)->um_devvp; |
| 1857 | struct inode *xp; |
| 1858 | struct vnode *vp = NULL; |
| 1859 | struct snap_info *si; |
| 1860 | |
| 1861 | si = VFSTOUFS(mp)->um_snapinfo; |
| 1862 | mutex_enter(&si->si_lock); |
| 1863 | while ((xp = TAILQ_FIRST(&si->si_snapshots)) != 0) { |
| 1864 | vp = ITOV(xp); |
| 1865 | TAILQ_REMOVE(&si->si_snapshots, xp, i_nextsnap); |
| 1866 | if (xp->i_snapblklist == si->si_snapblklist) |
| 1867 | si->si_snapblklist = NULL; |
| 1868 | free(xp->i_snapblklist, M_UFSMNT); |
| 1869 | if (xp->i_nlink > 0) { |
| 1870 | si->si_gen++; |
| 1871 | mutex_exit(&si->si_lock); |
| 1872 | vrele(vp); |
| 1873 | mutex_enter(&si->si_lock); |
| 1874 | } |
| 1875 | } |
| 1876 | si->si_gen++; |
| 1877 | mutex_exit(&si->si_lock); |
| 1878 | if (vp) |
| 1879 | fscow_disestablish(mp, ffs_copyonwrite, devvp); |
| 1880 | } |
| 1881 | |
| 1882 | /* |
| 1883 | * Check for need to copy block that is about to be written, |
| 1884 | * copying the block if necessary. |
| 1885 | */ |
| 1886 | static int |
| 1887 | ffs_copyonwrite(void *v, struct buf *bp, bool data_valid) |
| 1888 | { |
| 1889 | struct fs *fs; |
| 1890 | struct inode *ip; |
| 1891 | struct vnode *devvp = v, *vp = NULL; |
| 1892 | struct mount *mp = spec_node_getmountedfs(devvp); |
| 1893 | struct snap_info *si; |
| 1894 | void *saved_data = NULL; |
| 1895 | daddr_t lbn, blkno, *snapblklist; |
| 1896 | uint32_t gen; |
| 1897 | int lower, upper, mid, snapshot_locked = 0, error = 0; |
| 1898 | |
| 1899 | /* |
| 1900 | * Check for valid snapshots. |
| 1901 | */ |
| 1902 | si = VFSTOUFS(mp)->um_snapinfo; |
| 1903 | mutex_enter(&si->si_lock); |
| 1904 | ip = TAILQ_FIRST(&si->si_snapshots); |
| 1905 | if (ip == NULL) { |
| 1906 | mutex_exit(&si->si_lock); |
| 1907 | return 0; |
| 1908 | } |
| 1909 | /* |
| 1910 | * First check to see if it is after the file system, |
| 1911 | * in the journal or in the preallocated list. |
| 1912 | * By doing these checks we avoid several potential deadlocks. |
| 1913 | */ |
| 1914 | fs = ip->i_fs; |
| 1915 | lbn = ffs_fragstoblks(fs, FFS_DBTOFSB(fs, bp->b_blkno)); |
| 1916 | if (bp->b_blkno >= FFS_FSBTODB(fs, fs->fs_size)) { |
| 1917 | mutex_exit(&si->si_lock); |
| 1918 | return 0; |
| 1919 | } |
| 1920 | if ((fs->fs_flags & FS_DOWAPBL) && |
| 1921 | fs->fs_journal_location == UFS_WAPBL_JOURNALLOC_IN_FILESYSTEM) { |
| 1922 | off_t blk_off, log_start, log_end; |
| 1923 | |
| 1924 | log_start = (off_t)fs->fs_journallocs[UFS_WAPBL_INFS_ADDR] * |
| 1925 | fs->fs_journallocs[UFS_WAPBL_INFS_BLKSZ]; |
| 1926 | log_end = log_start + fs->fs_journallocs[UFS_WAPBL_INFS_COUNT] * |
| 1927 | fs->fs_journallocs[UFS_WAPBL_INFS_BLKSZ]; |
| 1928 | blk_off = dbtob(bp->b_blkno); |
| 1929 | if (blk_off >= log_start && blk_off < log_end) { |
| 1930 | mutex_exit(&si->si_lock); |
| 1931 | return 0; |
| 1932 | } |
| 1933 | } |
| 1934 | snapblklist = si->si_snapblklist; |
| 1935 | upper = (snapblklist != NULL ? snapblklist[0] - 1 : 0); |
| 1936 | lower = 1; |
| 1937 | while (lower <= upper) { |
| 1938 | mid = (lower + upper) / 2; |
| 1939 | if (snapblklist[mid] == lbn) |
| 1940 | break; |
| 1941 | if (snapblklist[mid] < lbn) |
| 1942 | lower = mid + 1; |
| 1943 | else |
| 1944 | upper = mid - 1; |
| 1945 | } |
| 1946 | if (lower <= upper) { |
| 1947 | mutex_exit(&si->si_lock); |
| 1948 | return 0; |
| 1949 | } |
| 1950 | /* |
| 1951 | * Not in the precomputed list, so check the snapshots. |
| 1952 | */ |
| 1953 | if (si->si_owner != curlwp) { |
| 1954 | if (!mutex_tryenter(&si->si_snaplock)) { |
| 1955 | mutex_exit(&si->si_lock); |
| 1956 | mutex_enter(&si->si_snaplock); |
| 1957 | mutex_enter(&si->si_lock); |
| 1958 | } |
| 1959 | si->si_owner = curlwp; |
| 1960 | snapshot_locked = 1; |
| 1961 | } |
| 1962 | if (data_valid && bp->b_bcount == fs->fs_bsize) |
| 1963 | saved_data = bp->b_data; |
| 1964 | retry: |
| 1965 | gen = si->si_gen; |
| 1966 | TAILQ_FOREACH(ip, &si->si_snapshots, i_nextsnap) { |
| 1967 | vp = ITOV(ip); |
| 1968 | /* |
| 1969 | * We ensure that everything of our own that needs to be |
| 1970 | * copied will be done at the time that ffs_snapshot is |
| 1971 | * called. Thus we can skip the check here which can |
| 1972 | * deadlock in doing the lookup in ffs_balloc. |
| 1973 | */ |
| 1974 | if (bp->b_vp == vp) |
| 1975 | continue; |
| 1976 | /* |
| 1977 | * Check to see if block needs to be copied. |
| 1978 | */ |
| 1979 | if (lbn < UFS_NDADDR) { |
| 1980 | blkno = db_get(ip, lbn); |
| 1981 | } else { |
| 1982 | mutex_exit(&si->si_lock); |
| 1983 | blkno = 0; /* XXX: GCC */ |
| 1984 | if ((error = snapblkaddr(vp, lbn, &blkno)) != 0) { |
| 1985 | mutex_enter(&si->si_lock); |
| 1986 | break; |
| 1987 | } |
| 1988 | mutex_enter(&si->si_lock); |
| 1989 | if (gen != si->si_gen) |
| 1990 | goto retry; |
| 1991 | } |
| 1992 | #ifdef DIAGNOSTIC |
| 1993 | if (blkno == BLK_SNAP && bp->b_lblkno >= 0) |
| 1994 | panic("ffs_copyonwrite: bad copy block" ); |
| 1995 | #endif |
| 1996 | if (blkno != 0) |
| 1997 | continue; |
| 1998 | |
| 1999 | if (curlwp == uvm.pagedaemon_lwp) { |
| 2000 | error = ENOMEM; |
| 2001 | break; |
| 2002 | } |
| 2003 | /* Only one level of recursion allowed. */ |
| 2004 | KASSERT(snapshot_locked); |
| 2005 | /* |
| 2006 | * Allocate the block into which to do the copy. Since |
| 2007 | * multiple processes may all try to copy the same block, |
| 2008 | * we have to recheck our need to do a copy if we sleep |
| 2009 | * waiting for the lock. |
| 2010 | * |
| 2011 | * Because all snapshots on a filesystem share a single |
| 2012 | * lock, we ensure that we will never be in competition |
| 2013 | * with another process to allocate a block. |
| 2014 | */ |
| 2015 | #ifdef DEBUG |
| 2016 | if (snapdebug) { |
| 2017 | printf("Copyonwrite: snapino %llu lbn %" PRId64 " for " , |
| 2018 | (unsigned long long)ip->i_number, lbn); |
| 2019 | if (bp->b_vp == devvp) |
| 2020 | printf("fs metadata" ); |
| 2021 | else |
| 2022 | printf("inum %llu" , (unsigned long long) |
| 2023 | VTOI(bp->b_vp)->i_number); |
| 2024 | printf(" lblkno %" PRId64 "\n" , bp->b_lblkno); |
| 2025 | } |
| 2026 | #endif |
| 2027 | /* |
| 2028 | * If we have already read the old block contents, then |
| 2029 | * simply copy them to the new block. Note that we need |
| 2030 | * to synchronously write snapshots that have not been |
| 2031 | * unlinked, and hence will be visible after a crash, |
| 2032 | * to ensure their integrity. |
| 2033 | */ |
| 2034 | mutex_exit(&si->si_lock); |
| 2035 | if (saved_data == NULL) { |
| 2036 | saved_data = malloc(fs->fs_bsize, M_UFSMNT, M_WAITOK); |
| 2037 | error = rwfsblk(vp, B_READ, saved_data, lbn); |
| 2038 | if (error) { |
| 2039 | free(saved_data, M_UFSMNT); |
| 2040 | saved_data = NULL; |
| 2041 | mutex_enter(&si->si_lock); |
| 2042 | break; |
| 2043 | } |
| 2044 | } |
| 2045 | error = wrsnapblk(vp, saved_data, lbn); |
| 2046 | if (error == 0 && ip->i_nlink > 0 && mp->mnt_wapbl) |
| 2047 | error = syncsnap(vp); |
| 2048 | mutex_enter(&si->si_lock); |
| 2049 | if (error) |
| 2050 | break; |
| 2051 | if (gen != si->si_gen) |
| 2052 | goto retry; |
| 2053 | } |
| 2054 | /* |
| 2055 | * Note that we need to synchronously write snapshots that |
| 2056 | * have not been unlinked, and hence will be visible after |
| 2057 | * a crash, to ensure their integrity. |
| 2058 | */ |
| 2059 | if (snapshot_locked) { |
| 2060 | si->si_owner = NULL; |
| 2061 | mutex_exit(&si->si_lock); |
| 2062 | mutex_exit(&si->si_snaplock); |
| 2063 | } else |
| 2064 | mutex_exit(&si->si_lock); |
| 2065 | if (saved_data && saved_data != bp->b_data) |
| 2066 | free(saved_data, M_UFSMNT); |
| 2067 | return error; |
| 2068 | } |
| 2069 | |
| 2070 | /* |
| 2071 | * Read from a snapshot. |
| 2072 | */ |
| 2073 | int |
| 2074 | ffs_snapshot_read(struct vnode *vp, struct uio *uio, int ioflag) |
| 2075 | { |
| 2076 | struct inode *ip = VTOI(vp); |
| 2077 | struct fs *fs = ip->i_fs; |
| 2078 | struct snap_info *si = VFSTOUFS(vp->v_mount)->um_snapinfo; |
| 2079 | struct buf *bp; |
| 2080 | daddr_t lbn, nextlbn; |
| 2081 | off_t fsbytes, bytesinfile; |
| 2082 | long size, xfersize, blkoffset; |
| 2083 | int error; |
| 2084 | |
| 2085 | fstrans_start(vp->v_mount, FSTRANS_SHARED); |
| 2086 | mutex_enter(&si->si_snaplock); |
| 2087 | |
| 2088 | if (ioflag & IO_ALTSEMANTICS) |
| 2089 | fsbytes = ip->i_size; |
| 2090 | else |
| 2091 | fsbytes = ffs_lfragtosize(fs, fs->fs_size); |
| 2092 | for (error = 0, bp = NULL; uio->uio_resid > 0; bp = NULL) { |
| 2093 | bytesinfile = fsbytes - uio->uio_offset; |
| 2094 | if (bytesinfile <= 0) |
| 2095 | break; |
| 2096 | lbn = ffs_lblkno(fs, uio->uio_offset); |
| 2097 | nextlbn = lbn + 1; |
| 2098 | size = fs->fs_bsize; |
| 2099 | blkoffset = ffs_blkoff(fs, uio->uio_offset); |
| 2100 | xfersize = MIN(MIN(fs->fs_bsize - blkoffset, uio->uio_resid), |
| 2101 | bytesinfile); |
| 2102 | |
| 2103 | if (ffs_lblktosize(fs, nextlbn + 1) >= fsbytes) { |
| 2104 | if (ffs_lblktosize(fs, lbn) + size > fsbytes) |
| 2105 | size = ffs_fragroundup(fs, |
| 2106 | fsbytes - ffs_lblktosize(fs, lbn)); |
| 2107 | error = bread(vp, lbn, size, 0, &bp); |
| 2108 | } else { |
| 2109 | int nextsize = fs->fs_bsize; |
| 2110 | error = breadn(vp, lbn, |
| 2111 | size, &nextlbn, &nextsize, 1, 0, &bp); |
| 2112 | } |
| 2113 | if (error) |
| 2114 | break; |
| 2115 | |
| 2116 | /* |
| 2117 | * We should only get non-zero b_resid when an I/O error |
| 2118 | * has occurred, which should cause us to break above. |
| 2119 | * However, if the short read did not cause an error, |
| 2120 | * then we want to ensure that we do not uiomove bad |
| 2121 | * or uninitialized data. |
| 2122 | */ |
| 2123 | size -= bp->b_resid; |
| 2124 | if (size < blkoffset + xfersize) { |
| 2125 | xfersize = size - blkoffset; |
| 2126 | if (xfersize <= 0) |
| 2127 | break; |
| 2128 | } |
| 2129 | error = uiomove((char *)bp->b_data + blkoffset, xfersize, uio); |
| 2130 | if (error) |
| 2131 | break; |
| 2132 | brelse(bp, BC_AGE); |
| 2133 | } |
| 2134 | if (bp != NULL) |
| 2135 | brelse(bp, BC_AGE); |
| 2136 | |
| 2137 | mutex_exit(&si->si_snaplock); |
| 2138 | fstrans_done(vp->v_mount); |
| 2139 | return error; |
| 2140 | } |
| 2141 | |
| 2142 | /* |
| 2143 | * Lookup a snapshots data block address. |
| 2144 | * Simpler than UFS_BALLOC() as we know all metadata is already allocated |
| 2145 | * and safe even for the pagedaemon where we cannot bread(). |
| 2146 | */ |
| 2147 | static int |
| 2148 | snapblkaddr(struct vnode *vp, daddr_t lbn, daddr_t *res) |
| 2149 | { |
| 2150 | struct indir indirs[UFS_NIADDR + 2]; |
| 2151 | struct inode *ip = VTOI(vp); |
| 2152 | struct fs *fs = ip->i_fs; |
| 2153 | struct buf *bp; |
| 2154 | int error, num; |
| 2155 | |
| 2156 | KASSERT(lbn >= 0); |
| 2157 | |
| 2158 | if (lbn < UFS_NDADDR) { |
| 2159 | *res = db_get(ip, lbn); |
| 2160 | return 0; |
| 2161 | } |
| 2162 | if ((error = ufs_getlbns(vp, lbn, indirs, &num)) != 0) |
| 2163 | return error; |
| 2164 | if (curlwp == uvm.pagedaemon_lwp) { |
| 2165 | mutex_enter(&bufcache_lock); |
| 2166 | bp = incore(vp, indirs[num-1].in_lbn); |
| 2167 | if (bp && (bp->b_oflags & (BO_DONE | BO_DELWRI))) { |
| 2168 | *res = idb_get(ip, bp->b_data, indirs[num-1].in_off); |
| 2169 | error = 0; |
| 2170 | } else |
| 2171 | error = ENOMEM; |
| 2172 | mutex_exit(&bufcache_lock); |
| 2173 | return error; |
| 2174 | } |
| 2175 | error = bread(vp, indirs[num-1].in_lbn, fs->fs_bsize, 0, &bp); |
| 2176 | if (error == 0) { |
| 2177 | *res = idb_get(ip, bp->b_data, indirs[num-1].in_off); |
| 2178 | brelse(bp, 0); |
| 2179 | } |
| 2180 | |
| 2181 | return error; |
| 2182 | } |
| 2183 | |
| 2184 | /* |
| 2185 | * Read or write the specified block of the filesystem vp resides on |
| 2186 | * from or to the disk bypassing the buffer cache. |
| 2187 | */ |
| 2188 | static int |
| 2189 | rwfsblk(struct vnode *vp, int flags, void *data, daddr_t lbn) |
| 2190 | { |
| 2191 | int error; |
| 2192 | struct inode *ip = VTOI(vp); |
| 2193 | struct fs *fs = ip->i_fs; |
| 2194 | struct buf *nbp; |
| 2195 | |
| 2196 | nbp = getiobuf(NULL, true); |
| 2197 | nbp->b_flags = flags; |
| 2198 | nbp->b_bcount = nbp->b_bufsize = fs->fs_bsize; |
| 2199 | nbp->b_error = 0; |
| 2200 | nbp->b_data = data; |
| 2201 | nbp->b_blkno = nbp->b_rawblkno = FFS_FSBTODB(fs, ffs_blkstofrags(fs, lbn)); |
| 2202 | nbp->b_proc = NULL; |
| 2203 | nbp->b_dev = ip->i_devvp->v_rdev; |
| 2204 | SET(nbp->b_cflags, BC_BUSY); /* mark buffer busy */ |
| 2205 | |
| 2206 | bdev_strategy(nbp); |
| 2207 | |
| 2208 | error = biowait(nbp); |
| 2209 | |
| 2210 | putiobuf(nbp); |
| 2211 | |
| 2212 | return error; |
| 2213 | } |
| 2214 | |
| 2215 | /* |
| 2216 | * Write all dirty buffers to disk and invalidate them. |
| 2217 | */ |
| 2218 | static int |
| 2219 | syncsnap(struct vnode *vp) |
| 2220 | { |
| 2221 | int error; |
| 2222 | buf_t *bp; |
| 2223 | struct fs *fs = VTOI(vp)->i_fs; |
| 2224 | |
| 2225 | mutex_enter(&bufcache_lock); |
| 2226 | while ((bp = LIST_FIRST(&vp->v_dirtyblkhd))) { |
| 2227 | error = bbusy(bp, false, 0, NULL); |
| 2228 | if (error == EPASSTHROUGH) |
| 2229 | continue; |
| 2230 | else if (error != 0) { |
| 2231 | mutex_exit(&bufcache_lock); |
| 2232 | return error; |
| 2233 | } |
| 2234 | KASSERT(bp->b_bcount == fs->fs_bsize); |
| 2235 | mutex_exit(&bufcache_lock); |
| 2236 | error = rwfsblk(vp, B_WRITE, bp->b_data, |
| 2237 | ffs_fragstoblks(fs, FFS_DBTOFSB(fs, bp->b_blkno))); |
| 2238 | brelse(bp, BC_INVAL | BC_VFLUSH); |
| 2239 | if (error) |
| 2240 | return error; |
| 2241 | mutex_enter(&bufcache_lock); |
| 2242 | } |
| 2243 | mutex_exit(&bufcache_lock); |
| 2244 | |
| 2245 | return 0; |
| 2246 | } |
| 2247 | |
| 2248 | /* |
| 2249 | * Write the specified block to a snapshot. |
| 2250 | */ |
| 2251 | static int |
| 2252 | wrsnapblk(struct vnode *vp, void *data, daddr_t lbn) |
| 2253 | { |
| 2254 | struct inode *ip = VTOI(vp); |
| 2255 | struct fs *fs = ip->i_fs; |
| 2256 | struct buf *bp; |
| 2257 | int error; |
| 2258 | |
| 2259 | error = ffs_balloc(vp, ffs_lblktosize(fs, (off_t)lbn), fs->fs_bsize, |
| 2260 | FSCRED, (ip->i_nlink > 0 ? B_SYNC : 0), &bp); |
| 2261 | if (error) |
| 2262 | return error; |
| 2263 | memcpy(bp->b_data, data, fs->fs_bsize); |
| 2264 | if (ip->i_nlink > 0) |
| 2265 | error = bwrite(bp); |
| 2266 | else |
| 2267 | bawrite(bp); |
| 2268 | |
| 2269 | return error; |
| 2270 | } |
| 2271 | |
| 2272 | /* |
| 2273 | * Check if this inode is present on the active snapshot list. |
| 2274 | * Must be called with snapinfo locked. |
| 2275 | */ |
| 2276 | static inline bool |
| 2277 | is_active_snapshot(struct snap_info *si, struct inode *ip) |
| 2278 | { |
| 2279 | struct inode *xp; |
| 2280 | |
| 2281 | KASSERT(mutex_owned(&si->si_lock)); |
| 2282 | |
| 2283 | TAILQ_FOREACH(xp, &si->si_snapshots, i_nextsnap) |
| 2284 | if (xp == ip) |
| 2285 | return true; |
| 2286 | return false; |
| 2287 | } |
| 2288 | |
| 2289 | /* |
| 2290 | * Get/Put direct block from inode or buffer containing disk addresses. Take |
| 2291 | * care for fs type (UFS1/UFS2) and byte swapping. These functions should go |
| 2292 | * into a global include. |
| 2293 | */ |
| 2294 | static inline daddr_t |
| 2295 | db_get(struct inode *ip, int loc) |
| 2296 | { |
| 2297 | if (ip->i_ump->um_fstype == UFS1) |
| 2298 | return ufs_rw32(ip->i_ffs1_db[loc], UFS_IPNEEDSWAP(ip)); |
| 2299 | else |
| 2300 | return ufs_rw64(ip->i_ffs2_db[loc], UFS_IPNEEDSWAP(ip)); |
| 2301 | } |
| 2302 | |
| 2303 | static inline void |
| 2304 | db_assign(struct inode *ip, int loc, daddr_t val) |
| 2305 | { |
| 2306 | if (ip->i_ump->um_fstype == UFS1) |
| 2307 | ip->i_ffs1_db[loc] = ufs_rw32(val, UFS_IPNEEDSWAP(ip)); |
| 2308 | else |
| 2309 | ip->i_ffs2_db[loc] = ufs_rw64(val, UFS_IPNEEDSWAP(ip)); |
| 2310 | } |
| 2311 | |
| 2312 | __unused static inline daddr_t |
| 2313 | ib_get(struct inode *ip, int loc) |
| 2314 | { |
| 2315 | if (ip->i_ump->um_fstype == UFS1) |
| 2316 | return ufs_rw32(ip->i_ffs1_ib[loc], UFS_IPNEEDSWAP(ip)); |
| 2317 | else |
| 2318 | return ufs_rw64(ip->i_ffs2_ib[loc], UFS_IPNEEDSWAP(ip)); |
| 2319 | } |
| 2320 | |
| 2321 | static inline daddr_t |
| 2322 | idb_get(struct inode *ip, void *bf, int loc) |
| 2323 | { |
| 2324 | if (ip->i_ump->um_fstype == UFS1) |
| 2325 | return ufs_rw32(((int32_t *)(bf))[loc], UFS_IPNEEDSWAP(ip)); |
| 2326 | else |
| 2327 | return ufs_rw64(((int64_t *)(bf))[loc], UFS_IPNEEDSWAP(ip)); |
| 2328 | } |
| 2329 | |
| 2330 | static inline void |
| 2331 | idb_assign(struct inode *ip, void *bf, int loc, daddr_t val) |
| 2332 | { |
| 2333 | if (ip->i_ump->um_fstype == UFS1) |
| 2334 | ((int32_t *)(bf))[loc] = ufs_rw32(val, UFS_IPNEEDSWAP(ip)); |
| 2335 | else |
| 2336 | ((int64_t *)(bf))[loc] = ufs_rw64(val, UFS_IPNEEDSWAP(ip)); |
| 2337 | } |
| 2338 | |