2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright 2000 Marshall Kirk McKusick. All Rights Reserved.
6 * Further information about snapshots can be obtained from:
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
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
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.
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
35 * @(#)ffs_snapshot.c 8.11 (McKusick) 7/23/00
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
41 #include "opt_quota.h"
43 #include <sys/param.h>
44 #include <sys/kernel.h>
45 #include <sys/systm.h>
49 #include <sys/fcntl.h>
51 #include <sys/namei.h>
52 #include <sys/sched.h>
54 #include <sys/malloc.h>
55 #include <sys/mount.h>
56 #include <sys/resource.h>
57 #include <sys/resourcevar.h>
58 #include <sys/rwlock.h>
59 #include <sys/vnode.h>
61 #include <geom/geom.h>
63 #include <ufs/ufs/extattr.h>
64 #include <ufs/ufs/quota.h>
65 #include <ufs/ufs/ufsmount.h>
66 #include <ufs/ufs/inode.h>
67 #include <ufs/ufs/ufs_extern.h>
69 #include <ufs/ffs/fs.h>
70 #include <ufs/ffs/ffs_extern.h>
72 #define KERNCRED thread0.td_ucred
77 #ifdef NO_FFS_SNAPSHOT
79 ffs_snapshot(mp, snapfile)
87 ffs_snapblkfree(fs, devvp, bno, size, inum, vtype, wkhd)
94 struct workhead *wkhd;
106 ffs_snapshot_mount(mp)
112 ffs_snapshot_unmount(mp)
124 ffs_copyonwrite(devvp, bp)
132 ffs_sync_snap(mp, waitfor)
139 FEATURE(ffs_snapshot, "FFS snapshot support");
141 LIST_HEAD(, snapdata) snapfree;
142 static struct mtx snapfree_lock;
143 MTX_SYSINIT(ffs_snapfree, &snapfree_lock, "snapdata free list", MTX_DEF);
145 static int cgaccount(int, struct vnode *, struct buf *, int);
146 static int expunge_ufs1(struct vnode *, struct inode *, struct fs *,
147 int (*)(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *, struct fs *,
148 ufs_lbn_t, int), int, int);
149 static int indiracct_ufs1(struct vnode *, struct vnode *, int,
150 ufs1_daddr_t, ufs_lbn_t, ufs_lbn_t, ufs_lbn_t, ufs_lbn_t, struct fs *,
151 int (*)(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *, struct fs *,
152 ufs_lbn_t, int), int);
153 static int fullacct_ufs1(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *,
154 struct fs *, ufs_lbn_t, int);
155 static int snapacct_ufs1(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *,
156 struct fs *, ufs_lbn_t, int);
157 static int mapacct_ufs1(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *,
158 struct fs *, ufs_lbn_t, int);
159 static int expunge_ufs2(struct vnode *, struct inode *, struct fs *,
160 int (*)(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *, struct fs *,
161 ufs_lbn_t, int), int, int);
162 static int indiracct_ufs2(struct vnode *, struct vnode *, int,
163 ufs2_daddr_t, ufs_lbn_t, ufs_lbn_t, ufs_lbn_t, ufs_lbn_t, struct fs *,
164 int (*)(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *, struct fs *,
165 ufs_lbn_t, int), int);
166 static int fullacct_ufs2(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *,
167 struct fs *, ufs_lbn_t, int);
168 static int snapacct_ufs2(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *,
169 struct fs *, ufs_lbn_t, int);
170 static int mapacct_ufs2(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *,
171 struct fs *, ufs_lbn_t, int);
172 static int readblock(struct vnode *vp, struct buf *, ufs2_daddr_t);
173 static void try_free_snapdata(struct vnode *devvp);
174 static struct snapdata *ffs_snapdata_acquire(struct vnode *devvp);
175 static int ffs_bp_snapblk(struct vnode *, struct buf *);
178 * To ensure the consistency of snapshots across crashes, we must
179 * synchronously write out copied blocks before allowing the
180 * originals to be modified. Because of the rather severe speed
181 * penalty that this imposes, the code normally only ensures
182 * persistence for the filesystem metadata contained within a
183 * snapshot. Setting the following flag allows this crash
184 * persistence to be enabled for file contents.
186 int dopersistence = 0;
189 #include <sys/sysctl.h>
190 SYSCTL_INT(_debug, OID_AUTO, dopersistence, CTLFLAG_RW, &dopersistence, 0, "");
191 static int snapdebug = 0;
192 SYSCTL_INT(_debug, OID_AUTO, snapdebug, CTLFLAG_RW, &snapdebug, 0, "");
193 int collectsnapstats = 0;
194 SYSCTL_INT(_debug, OID_AUTO, collectsnapstats, CTLFLAG_RW, &collectsnapstats,
199 * Create a snapshot file and initialize it for the filesystem.
202 ffs_snapshot(mp, snapfile)
206 ufs2_daddr_t numblks, blkno, *blkp, *snapblklist;
207 int error, cg, snaploc;
208 int i, size, len, loc;
209 ufs2_daddr_t blockno;
211 struct timespec starttime = {0, 0}, endtime;
213 long redo = 0, snaplistsize = 0;
216 struct fs *copy_fs = NULL, *fs;
217 struct thread *td = curthread;
218 struct inode *ip, *xp;
219 struct buf *bp, *nbp, *ibp;
223 struct vnode *vp, *xvp, *mvp, *devvp;
227 struct ufsmount *ump;
233 * At the moment, journaled soft updates cannot support
236 if (MOUNTEDSUJ(mp)) {
237 vfs_mount_error(mp, "%s: Snapshots are not yet supported when "
238 "running with journaled soft updates", fs->fs_fsmnt);
245 * Need to serialize access to snapshot code per filesystem.
248 * Assign a snapshot slot in the superblock.
251 for (snaploc = 0; snaploc < FSMAXSNAP; snaploc++)
252 if (fs->fs_snapinum[snaploc] == 0)
255 if (snaploc == FSMAXSNAP)
258 * Create the snapshot file.
261 NDINIT(&nd, CREATE, LOCKPARENT | LOCKLEAF | NOCACHE, UIO_SYSSPACE,
263 if ((error = namei(&nd)) != 0)
265 if (nd.ni_vp != NULL) {
269 if (nd.ni_dvp->v_mount != mp)
272 NDFREE(&nd, NDF_ONLY_PNBUF);
273 if (nd.ni_dvp == nd.ni_vp)
281 vat.va_mode = S_IRUSR;
282 vat.va_vaflags |= VA_EXCLUSIVE;
283 if (VOP_GETWRITEMOUNT(nd.ni_dvp, &wrtmp))
286 panic("ffs_snapshot: mount mismatch");
288 if (vn_start_write(NULL, &wrtmp, V_NOWAIT) != 0) {
289 NDFREE(&nd, NDF_ONLY_PNBUF);
291 if ((error = vn_start_write(NULL, &wrtmp,
292 V_XSLEEP | PCATCH)) != 0)
296 error = VOP_CREATE(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vat);
297 VOP_UNLOCK(nd.ni_dvp, 0);
299 NDFREE(&nd, NDF_ONLY_PNBUF);
300 vn_finished_write(wrtmp);
305 vp->v_vflag |= VV_SYSTEM;
307 devvp = ITODEVVP(ip);
309 * Allocate and copy the last block contents so as to be able
310 * to set size to that of the filesystem.
312 numblks = howmany(fs->fs_size, fs->fs_frag);
313 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)(numblks - 1)),
314 fs->fs_bsize, KERNCRED, BA_CLRBUF, &bp);
317 ip->i_size = lblktosize(fs, (off_t)numblks);
318 DIP_SET(ip, i_size, ip->i_size);
319 ip->i_flag |= IN_CHANGE | IN_UPDATE;
320 error = readblock(vp, bp, numblks - 1);
325 * Preallocate critical data structures so that we can copy
326 * them in without further allocation after we suspend all
327 * operations on the filesystem. We would like to just release
328 * the allocated buffers without writing them since they will
329 * be filled in below once we are ready to go, but this upsets
330 * the soft update code, so we go ahead and write the new buffers.
332 * Allocate all indirect blocks and mark all of them as not
333 * needing to be copied.
335 for (blkno = UFS_NDADDR; blkno < numblks; blkno += NINDIR(fs)) {
336 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)blkno),
337 fs->fs_bsize, td->td_ucred, BA_METAONLY, &ibp);
343 * Allocate copies for the superblock and its summary information.
345 error = UFS_BALLOC(vp, fs->fs_sblockloc, fs->fs_sbsize, KERNCRED,
350 blkno = fragstoblks(fs, fs->fs_csaddr);
351 len = howmany(fs->fs_cssize, fs->fs_bsize);
352 for (loc = 0; loc < len; loc++) {
353 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)(blkno + loc)),
354 fs->fs_bsize, KERNCRED, 0, &nbp);
360 * Allocate all cylinder group blocks.
362 for (cg = 0; cg < fs->fs_ncg; cg++) {
363 error = UFS_BALLOC(vp, lfragtosize(fs, cgtod(fs, cg)),
364 fs->fs_bsize, KERNCRED, 0, &nbp);
369 ffs_syncvnode(vp, MNT_WAIT, 0);
372 * Copy all the cylinder group maps. Although the
373 * filesystem is still active, we hope that only a few
374 * cylinder groups will change between now and when we
375 * suspend operations. Thus, we will be able to quickly
376 * touch up the few cylinder groups that changed during
377 * the suspension period.
379 len = howmany(fs->fs_ncg, NBBY);
380 space = malloc(len, M_DEVBUF, M_WAITOK|M_ZERO);
382 fs->fs_active = space;
384 for (cg = 0; cg < fs->fs_ncg; cg++) {
385 error = UFS_BALLOC(vp, lfragtosize(fs, cgtod(fs, cg)),
386 fs->fs_bsize, KERNCRED, 0, &nbp);
389 error = cgaccount(cg, vp, nbp, 1);
392 ffs_syncvnode(vp, MNT_WAIT, 0);
397 * Change inode to snapshot type file.
399 ip->i_flags |= SF_SNAPSHOT;
400 DIP_SET(ip, i_flags, ip->i_flags);
401 ip->i_flag |= IN_CHANGE | IN_UPDATE;
403 * Ensure that the snapshot is completely on disk.
404 * Since we have marked it as a snapshot it is safe to
405 * unlock it as no process will be allowed to write to it.
407 if ((error = ffs_syncvnode(vp, MNT_WAIT, 0)) != 0)
411 * All allocations are done, so we can now snapshot the system.
413 * Recind nice scheduling while running with the filesystem suspended.
415 if (td->td_proc->p_nice > 0) {
420 saved_nice = p->p_nice;
425 * Suspend operation on filesystem.
428 vn_finished_write(wrtmp);
429 if ((error = vfs_write_suspend(vp->v_mount, 0)) != 0) {
430 vn_start_write(NULL, &wrtmp, V_WAIT);
431 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
434 if (mp->mnt_kern_flag & MNTK_SUSPENDED)
436 vn_start_write(NULL, &wrtmp, V_WAIT);
438 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
439 if (ip->i_effnlink == 0) {
440 error = ENOENT; /* Snapshot file unlinked */
443 if (collectsnapstats)
444 nanotime(&starttime);
446 /* The last block might have changed. Copy it again to be sure. */
447 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)(numblks - 1)),
448 fs->fs_bsize, KERNCRED, BA_CLRBUF, &bp);
451 error = readblock(vp, bp, numblks - 1);
452 bp->b_flags |= B_VALIDSUSPWRT;
457 * First, copy all the cylinder group maps that have changed.
459 for (cg = 0; cg < fs->fs_ncg; cg++) {
460 if ((ACTIVECGNUM(fs, cg) & ACTIVECGOFF(cg)) != 0)
463 error = UFS_BALLOC(vp, lfragtosize(fs, cgtod(fs, cg)),
464 fs->fs_bsize, KERNCRED, 0, &nbp);
467 error = cgaccount(cg, vp, nbp, 2);
473 * Grab a copy of the superblock and its summary information.
474 * We delay writing it until the suspension is released below.
476 copy_fs = malloc((u_long)fs->fs_bsize, M_UFSMNT, M_WAITOK);
477 bcopy(fs, copy_fs, fs->fs_sbsize);
478 if ((fs->fs_flags & (FS_UNCLEAN | FS_NEEDSFSCK)) == 0)
479 copy_fs->fs_clean = 1;
480 size = fs->fs_bsize < SBLOCKSIZE ? fs->fs_bsize : SBLOCKSIZE;
481 if (fs->fs_sbsize < size)
482 bzero(&((char *)copy_fs)[fs->fs_sbsize],
483 size - fs->fs_sbsize);
484 size = blkroundup(fs, fs->fs_cssize);
485 if (fs->fs_contigsumsize > 0)
486 size += fs->fs_ncg * sizeof(int32_t);
487 space = malloc((u_long)size, M_UFSMNT, M_WAITOK);
488 copy_fs->fs_csp = space;
489 bcopy(fs->fs_csp, copy_fs->fs_csp, fs->fs_cssize);
490 space = (char *)space + fs->fs_cssize;
491 loc = howmany(fs->fs_cssize, fs->fs_fsize);
492 i = fs->fs_frag - loc % fs->fs_frag;
493 len = (i == fs->fs_frag) ? 0 : i * fs->fs_fsize;
495 if ((error = bread(devvp, fsbtodb(fs, fs->fs_csaddr + loc),
496 len, KERNCRED, &bp)) != 0) {
498 free(copy_fs->fs_csp, M_UFSMNT);
499 free(copy_fs, M_UFSMNT);
503 bcopy(bp->b_data, space, (u_int)len);
504 space = (char *)space + len;
505 bp->b_flags |= B_INVAL | B_NOCACHE;
508 if (fs->fs_contigsumsize > 0) {
509 copy_fs->fs_maxcluster = lp = space;
510 for (i = 0; i < fs->fs_ncg; i++)
511 *lp++ = fs->fs_contigsumsize;
514 * We must check for active files that have been unlinked
515 * (e.g., with a zero link count). We have to expunge all
516 * trace of these files from the snapshot so that they are
517 * not reclaimed prematurely by fsck or unnecessarily dumped.
518 * We turn off the MNTK_SUSPENDED flag to avoid a panic from
519 * spec_strategy about writing on a suspended filesystem.
520 * Note that we skip unlinked snapshot files as they will
521 * be handled separately below.
523 * We also calculate the needed size for the snapshot list.
525 snaplistsize = fs->fs_ncg + howmany(fs->fs_cssize, fs->fs_bsize) +
526 FSMAXSNAP + 1 /* superblock */ + 1 /* last block */ + 1 /* size */;
528 mp->mnt_kern_flag &= ~MNTK_SUSPENDED;
531 MNT_VNODE_FOREACH_ALL(xvp, mp, mvp) {
532 if ((xvp->v_usecount == 0 &&
533 (xvp->v_iflag & (VI_OWEINACT | VI_DOINGINACT)) == 0) ||
534 xvp->v_type == VNON ||
535 IS_SNAPSHOT(VTOI(xvp))) {
540 * We can skip parent directory vnode because it must have
541 * this snapshot file in it.
543 if (xvp == nd.ni_dvp) {
548 if (vn_lock(xvp, LK_EXCLUSIVE | LK_INTERLOCK) != 0) {
549 MNT_VNODE_FOREACH_ALL_ABORT(mp, mvp);
554 if (xvp->v_usecount == 0 &&
555 (xvp->v_iflag & (VI_OWEINACT | VI_DOINGINACT)) == 0) {
563 vn_printf(xvp, "ffs_snapshot: busy vnode ");
564 if (VOP_GETATTR(xvp, &vat, td->td_ucred) == 0 &&
571 if (ffs_checkfreefile(copy_fs, vp, xp->i_number)) {
577 * If there is a fragment, clear it here.
580 loc = howmany(xp->i_size, fs->fs_bsize) - 1;
581 if (loc < UFS_NDADDR) {
582 len = fragroundup(fs, blkoff(fs, xp->i_size));
583 if (len != 0 && len < fs->fs_bsize) {
584 ffs_blkfree(ump, copy_fs, vp,
585 DIP(xp, i_db[loc]), len, xp->i_number,
586 xvp->v_type, NULL, SINGLETON_KEY);
587 blkno = DIP(xp, i_db[loc]);
588 DIP_SET(xp, i_db[loc], 0);
593 error = expunge_ufs1(vp, xp, copy_fs, fullacct_ufs1,
596 error = expunge_ufs2(vp, xp, copy_fs, fullacct_ufs2,
599 DIP_SET(xp, i_db[loc], blkno);
601 error = ffs_freefile(ump, copy_fs, vp, xp->i_number,
606 free(copy_fs->fs_csp, M_UFSMNT);
607 free(copy_fs, M_UFSMNT);
609 MNT_VNODE_FOREACH_ALL_ABORT(mp, mvp);
614 * Erase the journal file from the snapshot.
616 if (fs->fs_flags & FS_SUJ) {
617 error = softdep_journal_lookup(mp, &xvp);
619 free(copy_fs->fs_csp, M_UFSMNT);
620 free(copy_fs, M_UFSMNT);
626 error = expunge_ufs1(vp, xp, copy_fs, fullacct_ufs1,
629 error = expunge_ufs2(vp, xp, copy_fs, fullacct_ufs2,
634 * Acquire a lock on the snapdata structure, creating it if necessary.
636 sn = ffs_snapdata_acquire(devvp);
638 * Change vnode to use shared snapshot lock instead of the original
641 vp->v_vnlock = &sn->sn_lock;
642 lockmgr(&vp->v_lock, LK_RELEASE, NULL);
643 xp = TAILQ_FIRST(&sn->sn_head);
645 * If this is the first snapshot on this filesystem, then we need
646 * to allocate the space for the list of preallocated snapshot blocks.
647 * This list will be refined below, but this preliminary one will
648 * keep us out of deadlock until the full one is ready.
651 snapblklist = malloc(snaplistsize * sizeof(daddr_t),
653 blkp = &snapblklist[1];
654 *blkp++ = lblkno(fs, fs->fs_sblockloc);
655 blkno = fragstoblks(fs, fs->fs_csaddr);
656 for (cg = 0; cg < fs->fs_ncg; cg++) {
657 if (fragstoblks(fs, cgtod(fs, cg) > blkno))
659 *blkp++ = fragstoblks(fs, cgtod(fs, cg));
661 len = howmany(fs->fs_cssize, fs->fs_bsize);
662 for (loc = 0; loc < len; loc++)
663 *blkp++ = blkno + loc;
664 for (; cg < fs->fs_ncg; cg++)
665 *blkp++ = fragstoblks(fs, cgtod(fs, cg));
666 snapblklist[0] = blkp - snapblklist;
668 if (sn->sn_blklist != NULL)
669 panic("ffs_snapshot: non-empty list");
670 sn->sn_blklist = snapblklist;
671 sn->sn_listsize = blkp - snapblklist;
675 * Record snapshot inode. Since this is the newest snapshot,
676 * it must be placed at the end of the list.
679 fs->fs_snapinum[snaploc] = ip->i_number;
680 if (ip->i_nextsnap.tqe_prev != 0)
681 panic("ffs_snapshot: %ju already on list",
682 (uintmax_t)ip->i_number);
683 TAILQ_INSERT_TAIL(&sn->sn_head, ip, i_nextsnap);
684 devvp->v_vflag |= VV_COPYONWRITE;
686 ASSERT_VOP_LOCKED(vp, "ffs_snapshot vp");
688 KASSERT((sn != NULL && copy_fs != NULL && error == 0) ||
689 (sn == NULL && copy_fs == NULL && error != 0),
690 ("email phk@ and mckusick@"));
692 * Resume operation on filesystem.
694 vfs_write_resume(vp->v_mount, VR_START_WRITE | VR_NO_SUSPCLR);
695 if (collectsnapstats && starttime.tv_sec > 0) {
697 timespecsub(&endtime, &starttime, &endtime);
698 printf("%s: suspended %ld.%03ld sec, redo %ld of %d\n",
699 vp->v_mount->mnt_stat.f_mntonname, (long)endtime.tv_sec,
700 endtime.tv_nsec / 1000000, redo, fs->fs_ncg);
705 * Copy allocation information from all the snapshots in
706 * this snapshot and then expunge them from its view.
708 TAILQ_FOREACH(xp, &sn->sn_head, i_nextsnap) {
712 error = expunge_ufs1(vp, xp, fs, snapacct_ufs1,
715 error = expunge_ufs2(vp, xp, fs, snapacct_ufs2,
717 if (error == 0 && xp->i_effnlink == 0) {
718 error = ffs_freefile(ump,
725 fs->fs_snapinum[snaploc] = 0;
730 * Allocate space for the full list of preallocated snapshot blocks.
732 snapblklist = malloc(snaplistsize * sizeof(daddr_t),
734 ip->i_snapblklist = &snapblklist[1];
736 * Expunge the blocks used by the snapshots from the set of
737 * blocks marked as used in the snapshot bitmaps. Also, collect
738 * the list of allocated blocks in i_snapblklist.
741 error = expunge_ufs1(vp, ip, copy_fs, mapacct_ufs1,
744 error = expunge_ufs2(vp, ip, copy_fs, mapacct_ufs2,
747 fs->fs_snapinum[snaploc] = 0;
748 free(snapblklist, M_UFSMNT);
751 if (snaplistsize < ip->i_snapblklist - snapblklist)
752 panic("ffs_snapshot: list too small");
753 snaplistsize = ip->i_snapblklist - snapblklist;
754 snapblklist[0] = snaplistsize;
755 ip->i_snapblklist = 0;
757 * Write out the list of allocated blocks to the end of the snapshot.
759 auio.uio_iov = &aiov;
761 aiov.iov_base = (void *)snapblklist;
762 aiov.iov_len = snaplistsize * sizeof(daddr_t);
763 auio.uio_resid = aiov.iov_len;
764 auio.uio_offset = ip->i_size;
765 auio.uio_segflg = UIO_SYSSPACE;
766 auio.uio_rw = UIO_WRITE;
768 if ((error = VOP_WRITE(vp, &auio, IO_UNIT, td->td_ucred)) != 0) {
769 fs->fs_snapinum[snaploc] = 0;
770 free(snapblklist, M_UFSMNT);
774 * Write the superblock and its summary information
777 blkno = fragstoblks(fs, fs->fs_csaddr);
778 len = howmany(fs->fs_cssize, fs->fs_bsize);
779 space = copy_fs->fs_csp;
780 for (loc = 0; loc < len; loc++) {
781 error = bread(vp, blkno + loc, fs->fs_bsize, KERNCRED, &nbp);
784 fs->fs_snapinum[snaploc] = 0;
785 free(snapblklist, M_UFSMNT);
788 bcopy(space, nbp->b_data, fs->fs_bsize);
789 space = (char *)space + fs->fs_bsize;
792 error = bread(vp, lblkno(fs, fs->fs_sblockloc), fs->fs_bsize,
797 loc = blkoff(fs, fs->fs_sblockloc);
798 bcopy((char *)copy_fs, &nbp->b_data[loc], (u_int)fs->fs_sbsize);
802 * As this is the newest list, it is the most inclusive, so
803 * should replace the previous list.
806 space = sn->sn_blklist;
807 sn->sn_blklist = snapblklist;
808 sn->sn_listsize = snaplistsize;
811 free(space, M_UFSMNT);
813 * Preallocate all the direct blocks in the snapshot inode so
814 * that we never have to write the inode itself to commit an
815 * update to the contents of the snapshot. Note that once
816 * created, the size of the snapshot will never change, so
817 * there will never be a need to write the inode except to
818 * update the non-integrity-critical time fields and
819 * allocated-block count.
821 for (blockno = 0; blockno < UFS_NDADDR; blockno++) {
822 if (DIP(ip, i_db[blockno]) != 0)
824 error = UFS_BALLOC(vp, lblktosize(fs, blockno),
825 fs->fs_bsize, KERNCRED, BA_CLRBUF, &bp);
828 error = readblock(vp, bp, blockno);
834 free(copy_fs->fs_csp, M_UFSMNT);
835 free(copy_fs, M_UFSMNT);
838 NDFREE(&nd, NDF_ONLY_PNBUF);
839 if (saved_nice > 0) {
844 sched_nice(td->td_proc, saved_nice);
845 PROC_UNLOCK(td->td_proc);
848 if (fs->fs_active != 0) {
849 free(fs->fs_active, M_DEVBUF);
854 mp->mnt_flag = (mp->mnt_flag & MNT_QUOTA) | (flag & ~MNT_QUOTA);
857 (void) ffs_truncate(vp, (off_t)0, 0, NOCRED);
858 (void) ffs_syncvnode(vp, MNT_WAIT, 0);
864 vn_finished_write(wrtmp);
865 process_deferred_inactive(mp);
870 * Copy a cylinder group map. All the unallocated blocks are marked
871 * BLK_NOCOPY so that the snapshot knows that it need not copy them
872 * if they are later written. If passno is one, then this is a first
873 * pass, so only setting needs to be done. If passno is 2, then this
874 * is a revision to a previous pass which must be undone as the
875 * replacement pass is done.
878 cgaccount(cg, vp, nbp, passno)
884 struct buf *bp, *ibp;
888 ufs2_daddr_t base, numblks;
889 int error, len, loc, indiroff;
893 if ((error = ffs_getcg(fs, ITODEVVP(ip), cg, &bp, &cgp)) != 0)
895 UFS_LOCK(ITOUMP(ip));
898 * Recomputation of summary information might not have been performed
899 * at mount time. Sync up summary information for current cylinder
900 * group while data is in memory to ensure that result of background
901 * fsck is slightly more consistent.
903 fs->fs_cs(fs, cg) = cgp->cg_cs;
904 UFS_UNLOCK(ITOUMP(ip));
905 bcopy(bp->b_data, nbp->b_data, fs->fs_cgsize);
906 if (fs->fs_cgsize < fs->fs_bsize)
907 bzero(&nbp->b_data[fs->fs_cgsize],
908 fs->fs_bsize - fs->fs_cgsize);
909 cgp = (struct cg *)nbp->b_data;
912 nbp->b_flags |= B_VALIDSUSPWRT;
913 numblks = howmany(fs->fs_size, fs->fs_frag);
914 len = howmany(fs->fs_fpg, fs->fs_frag);
915 base = cgbase(fs, cg) / fs->fs_frag;
916 if (base + len >= numblks)
917 len = numblks - base - 1;
919 if (base < UFS_NDADDR) {
920 for ( ; loc < UFS_NDADDR; loc++) {
921 if (ffs_isblock(fs, cg_blksfree(cgp), loc))
922 DIP_SET(ip, i_db[loc], BLK_NOCOPY);
923 else if (passno == 2 && DIP(ip, i_db[loc])== BLK_NOCOPY)
924 DIP_SET(ip, i_db[loc], 0);
925 else if (passno == 1 && DIP(ip, i_db[loc])== BLK_NOCOPY)
926 panic("ffs_snapshot: lost direct block");
929 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)(base + loc)),
930 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp);
934 indiroff = (base + loc - UFS_NDADDR) % NINDIR(fs);
935 for ( ; loc < len; loc++, indiroff++) {
936 if (indiroff >= NINDIR(fs)) {
938 ibp->b_flags |= B_VALIDSUSPWRT;
940 error = UFS_BALLOC(vp,
941 lblktosize(fs, (off_t)(base + loc)),
942 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp);
949 if (ffs_isblock(fs, cg_blksfree(cgp), loc))
950 ((ufs1_daddr_t *)(ibp->b_data))[indiroff] =
952 else if (passno == 2 && ((ufs1_daddr_t *)(ibp->b_data))
953 [indiroff] == BLK_NOCOPY)
954 ((ufs1_daddr_t *)(ibp->b_data))[indiroff] = 0;
955 else if (passno == 1 && ((ufs1_daddr_t *)(ibp->b_data))
956 [indiroff] == BLK_NOCOPY)
957 panic("ffs_snapshot: lost indirect block");
960 if (ffs_isblock(fs, cg_blksfree(cgp), loc))
961 ((ufs2_daddr_t *)(ibp->b_data))[indiroff] = BLK_NOCOPY;
962 else if (passno == 2 &&
963 ((ufs2_daddr_t *)(ibp->b_data)) [indiroff] == BLK_NOCOPY)
964 ((ufs2_daddr_t *)(ibp->b_data))[indiroff] = 0;
965 else if (passno == 1 &&
966 ((ufs2_daddr_t *)(ibp->b_data)) [indiroff] == BLK_NOCOPY)
967 panic("ffs_snapshot: lost indirect block");
970 ibp->b_flags |= B_VALIDSUSPWRT;
974 * We have to calculate the crc32c here rather than just setting the
975 * BX_CYLGRP b_xflags because the allocation of the block for the
976 * the cylinder group map will always be a full size block (fs_bsize)
977 * even though the cylinder group may be smaller (fs_cgsize). The
978 * crc32c must be computed only over fs_cgsize whereas the BX_CYLGRP
979 * flag causes it to be computed over the size of the buffer.
981 if ((fs->fs_metackhash & CK_CYLGRP) != 0) {
982 ((struct cg *)nbp->b_data)->cg_ckhash = 0;
983 ((struct cg *)nbp->b_data)->cg_ckhash =
984 calculate_crc32c(~0L, nbp->b_data, fs->fs_cgsize);
990 * Before expunging a snapshot inode, note all the
991 * blocks that it claims with BLK_SNAP so that fsck will
992 * be able to account for those blocks properly and so
993 * that this snapshot knows that it need not copy them
994 * if the other snapshot holding them is freed. This code
995 * is reproduced once each for UFS1 and UFS2.
998 expunge_ufs1(snapvp, cancelip, fs, acctfunc, expungetype, clearmode)
999 struct vnode *snapvp;
1000 struct inode *cancelip;
1002 int (*acctfunc)(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *,
1003 struct fs *, ufs_lbn_t, int);
1007 int i, error, indiroff;
1008 ufs_lbn_t lbn, rlbn;
1009 ufs2_daddr_t len, blkno, numblks, blksperindir;
1010 struct ufs1_dinode *dip;
1011 struct thread *td = curthread;
1015 * Prepare to expunge the inode. If its inode block has not
1016 * yet been copied, then allocate and fill the copy.
1018 lbn = fragstoblks(fs, ino_to_fsba(fs, cancelip->i_number));
1020 if (lbn < UFS_NDADDR) {
1021 blkno = VTOI(snapvp)->i_din1->di_db[lbn];
1023 if (DOINGSOFTDEP(snapvp))
1024 softdep_prealloc(snapvp, MNT_WAIT);
1025 td->td_pflags |= TDP_COWINPROGRESS;
1026 error = ffs_balloc_ufs1(snapvp, lblktosize(fs, (off_t)lbn),
1027 fs->fs_bsize, KERNCRED, BA_METAONLY, &bp);
1028 td->td_pflags &= ~TDP_COWINPROGRESS;
1031 indiroff = (lbn - UFS_NDADDR) % NINDIR(fs);
1032 blkno = ((ufs1_daddr_t *)(bp->b_data))[indiroff];
1036 if ((error = bread(snapvp, lbn, fs->fs_bsize, KERNCRED, &bp)))
1039 error = ffs_balloc_ufs1(snapvp, lblktosize(fs, (off_t)lbn),
1040 fs->fs_bsize, KERNCRED, 0, &bp);
1043 if ((error = readblock(snapvp, bp, lbn)) != 0)
1047 * Set a snapshot inode to be a zero length file, regular files
1048 * or unlinked snapshots to be completely unallocated.
1050 dip = (struct ufs1_dinode *)bp->b_data +
1051 ino_to_fsbo(fs, cancelip->i_number);
1052 if (clearmode || cancelip->i_effnlink == 0)
1056 dip->di_flags &= ~SF_SNAPSHOT;
1057 bzero(&dip->di_db[0], (UFS_NDADDR + UFS_NIADDR) * sizeof(ufs1_daddr_t));
1060 * Now go through and expunge all the blocks in the file
1061 * using the function requested.
1063 numblks = howmany(cancelip->i_size, fs->fs_bsize);
1064 if ((error = (*acctfunc)(snapvp, &cancelip->i_din1->di_db[0],
1065 &cancelip->i_din1->di_db[UFS_NDADDR], fs, 0, expungetype)))
1067 if ((error = (*acctfunc)(snapvp, &cancelip->i_din1->di_ib[0],
1068 &cancelip->i_din1->di_ib[UFS_NIADDR], fs, -1, expungetype)))
1072 len = numblks - UFS_NDADDR;
1074 for (i = 0; len > 0 && i < UFS_NIADDR; i++) {
1075 error = indiracct_ufs1(snapvp, ITOV(cancelip), i,
1076 cancelip->i_din1->di_ib[i], lbn, rlbn, len,
1077 blksperindir, fs, acctfunc, expungetype);
1080 blksperindir *= NINDIR(fs);
1081 lbn -= blksperindir + 1;
1082 len -= blksperindir;
1083 rlbn += blksperindir;
1089 * Descend an indirect block chain for vnode cancelvp accounting for all
1090 * its indirect blocks in snapvp.
1093 indiracct_ufs1(snapvp, cancelvp, level, blkno, lbn, rlbn, remblks,
1094 blksperindir, fs, acctfunc, expungetype)
1095 struct vnode *snapvp;
1096 struct vnode *cancelvp;
1102 ufs_lbn_t blksperindir;
1104 int (*acctfunc)(struct vnode *, ufs1_daddr_t *, ufs1_daddr_t *,
1105 struct fs *, ufs_lbn_t, int);
1109 ufs_lbn_t subblksperindir;
1110 struct indir indirs[UFS_NIADDR + 2];
1111 ufs1_daddr_t last, *bap;
1115 if (expungetype == BLK_NOCOPY)
1117 panic("indiracct_ufs1: missing indir");
1119 if ((error = ufs_getlbns(cancelvp, rlbn, indirs, &num)) != 0)
1121 if (lbn != indirs[num - 1 - level].in_lbn || num < 2)
1122 panic("indiracct_ufs1: botched params");
1124 * We have to expand bread here since it will deadlock looking
1125 * up the block number for any blocks that are not in the cache.
1127 bp = getblk(cancelvp, lbn, fs->fs_bsize, 0, 0, 0);
1128 bp->b_blkno = fsbtodb(fs, blkno);
1129 if ((bp->b_flags & (B_DONE | B_DELWRI)) == 0 &&
1130 (error = readblock(cancelvp, bp, fragstoblks(fs, blkno)))) {
1135 * Account for the block pointers in this indirect block.
1137 last = howmany(remblks, blksperindir);
1138 if (last > NINDIR(fs))
1140 bap = malloc(fs->fs_bsize, M_DEVBUF, M_WAITOK);
1141 bcopy(bp->b_data, (caddr_t)bap, fs->fs_bsize);
1143 error = (*acctfunc)(snapvp, &bap[0], &bap[last], fs,
1144 level == 0 ? rlbn : -1, expungetype);
1145 if (error || level == 0)
1148 * Account for the block pointers in each of the indirect blocks
1149 * in the levels below us.
1151 subblksperindir = blksperindir / NINDIR(fs);
1152 for (lbn++, level--, i = 0; i < last; i++) {
1153 error = indiracct_ufs1(snapvp, cancelvp, level, bap[i], lbn,
1154 rlbn, remblks, subblksperindir, fs, acctfunc, expungetype);
1157 rlbn += blksperindir;
1158 lbn -= blksperindir;
1159 remblks -= blksperindir;
1162 free(bap, M_DEVBUF);
1167 * Do both snap accounting and map accounting.
1170 fullacct_ufs1(vp, oldblkp, lastblkp, fs, lblkno, exptype)
1172 ufs1_daddr_t *oldblkp, *lastblkp;
1175 int exptype; /* BLK_SNAP or BLK_NOCOPY */
1179 if ((error = snapacct_ufs1(vp, oldblkp, lastblkp, fs, lblkno, exptype)))
1181 return (mapacct_ufs1(vp, oldblkp, lastblkp, fs, lblkno, exptype));
1185 * Identify a set of blocks allocated in a snapshot inode.
1188 snapacct_ufs1(vp, oldblkp, lastblkp, fs, lblkno, expungetype)
1190 ufs1_daddr_t *oldblkp, *lastblkp;
1193 int expungetype; /* BLK_SNAP or BLK_NOCOPY */
1195 struct inode *ip = VTOI(vp);
1196 ufs1_daddr_t blkno, *blkp;
1201 for ( ; oldblkp < lastblkp; oldblkp++) {
1203 if (blkno == 0 || blkno == BLK_NOCOPY || blkno == BLK_SNAP)
1205 lbn = fragstoblks(fs, blkno);
1206 if (lbn < UFS_NDADDR) {
1207 blkp = &ip->i_din1->di_db[lbn];
1208 ip->i_flag |= IN_CHANGE | IN_UPDATE;
1210 error = ffs_balloc_ufs1(vp, lblktosize(fs, (off_t)lbn),
1211 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp);
1214 blkp = &((ufs1_daddr_t *)(ibp->b_data))
1215 [(lbn - UFS_NDADDR) % NINDIR(fs)];
1218 * If we are expunging a snapshot vnode and we
1219 * find a block marked BLK_NOCOPY, then it is
1220 * one that has been allocated to this snapshot after
1221 * we took our current snapshot and can be ignored.
1223 if (expungetype == BLK_SNAP && *blkp == BLK_NOCOPY) {
1224 if (lbn >= UFS_NDADDR)
1228 panic("snapacct_ufs1: bad block");
1229 *blkp = expungetype;
1230 if (lbn >= UFS_NDADDR)
1238 * Account for a set of blocks allocated in a snapshot inode.
1241 mapacct_ufs1(vp, oldblkp, lastblkp, fs, lblkno, expungetype)
1243 ufs1_daddr_t *oldblkp, *lastblkp;
1254 inum = ip->i_number;
1259 for ( ; oldblkp < lastblkp; oldblkp++, lblkno++) {
1261 if (blkno == 0 || blkno == BLK_NOCOPY)
1263 if (acctit && expungetype == BLK_SNAP && blkno != BLK_SNAP)
1264 *ip->i_snapblklist++ = lblkno;
1265 if (blkno == BLK_SNAP)
1266 blkno = blkstofrags(fs, lblkno);
1267 ffs_blkfree(ITOUMP(ip), fs, vp, blkno, fs->fs_bsize, inum,
1268 vp->v_type, NULL, SINGLETON_KEY);
1274 * Before expunging a snapshot inode, note all the
1275 * blocks that it claims with BLK_SNAP so that fsck will
1276 * be able to account for those blocks properly and so
1277 * that this snapshot knows that it need not copy them
1278 * if the other snapshot holding them is freed. This code
1279 * is reproduced once each for UFS1 and UFS2.
1282 expunge_ufs2(snapvp, cancelip, fs, acctfunc, expungetype, clearmode)
1283 struct vnode *snapvp;
1284 struct inode *cancelip;
1286 int (*acctfunc)(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *,
1287 struct fs *, ufs_lbn_t, int);
1291 int i, error, indiroff;
1292 ufs_lbn_t lbn, rlbn;
1293 ufs2_daddr_t len, blkno, numblks, blksperindir;
1294 struct ufs2_dinode *dip;
1295 struct thread *td = curthread;
1299 * Prepare to expunge the inode. If its inode block has not
1300 * yet been copied, then allocate and fill the copy.
1302 lbn = fragstoblks(fs, ino_to_fsba(fs, cancelip->i_number));
1304 if (lbn < UFS_NDADDR) {
1305 blkno = VTOI(snapvp)->i_din2->di_db[lbn];
1307 if (DOINGSOFTDEP(snapvp))
1308 softdep_prealloc(snapvp, MNT_WAIT);
1309 td->td_pflags |= TDP_COWINPROGRESS;
1310 error = ffs_balloc_ufs2(snapvp, lblktosize(fs, (off_t)lbn),
1311 fs->fs_bsize, KERNCRED, BA_METAONLY, &bp);
1312 td->td_pflags &= ~TDP_COWINPROGRESS;
1315 indiroff = (lbn - UFS_NDADDR) % NINDIR(fs);
1316 blkno = ((ufs2_daddr_t *)(bp->b_data))[indiroff];
1320 if ((error = bread(snapvp, lbn, fs->fs_bsize, KERNCRED, &bp)))
1323 error = ffs_balloc_ufs2(snapvp, lblktosize(fs, (off_t)lbn),
1324 fs->fs_bsize, KERNCRED, 0, &bp);
1327 if ((error = readblock(snapvp, bp, lbn)) != 0)
1331 * Set a snapshot inode to be a zero length file, regular files
1332 * to be completely unallocated.
1334 dip = (struct ufs2_dinode *)bp->b_data +
1335 ino_to_fsbo(fs, cancelip->i_number);
1336 if (clearmode || cancelip->i_effnlink == 0)
1340 dip->di_flags &= ~SF_SNAPSHOT;
1341 bzero(&dip->di_db[0], (UFS_NDADDR + UFS_NIADDR) * sizeof(ufs2_daddr_t));
1344 * Now go through and expunge all the blocks in the file
1345 * using the function requested.
1347 numblks = howmany(cancelip->i_size, fs->fs_bsize);
1348 if ((error = (*acctfunc)(snapvp, &cancelip->i_din2->di_db[0],
1349 &cancelip->i_din2->di_db[UFS_NDADDR], fs, 0, expungetype)))
1351 if ((error = (*acctfunc)(snapvp, &cancelip->i_din2->di_ib[0],
1352 &cancelip->i_din2->di_ib[UFS_NIADDR], fs, -1, expungetype)))
1356 len = numblks - UFS_NDADDR;
1358 for (i = 0; len > 0 && i < UFS_NIADDR; i++) {
1359 error = indiracct_ufs2(snapvp, ITOV(cancelip), i,
1360 cancelip->i_din2->di_ib[i], lbn, rlbn, len,
1361 blksperindir, fs, acctfunc, expungetype);
1364 blksperindir *= NINDIR(fs);
1365 lbn -= blksperindir + 1;
1366 len -= blksperindir;
1367 rlbn += blksperindir;
1373 * Descend an indirect block chain for vnode cancelvp accounting for all
1374 * its indirect blocks in snapvp.
1377 indiracct_ufs2(snapvp, cancelvp, level, blkno, lbn, rlbn, remblks,
1378 blksperindir, fs, acctfunc, expungetype)
1379 struct vnode *snapvp;
1380 struct vnode *cancelvp;
1386 ufs_lbn_t blksperindir;
1388 int (*acctfunc)(struct vnode *, ufs2_daddr_t *, ufs2_daddr_t *,
1389 struct fs *, ufs_lbn_t, int);
1393 ufs_lbn_t subblksperindir;
1394 struct indir indirs[UFS_NIADDR + 2];
1395 ufs2_daddr_t last, *bap;
1399 if (expungetype == BLK_NOCOPY)
1401 panic("indiracct_ufs2: missing indir");
1403 if ((error = ufs_getlbns(cancelvp, rlbn, indirs, &num)) != 0)
1405 if (lbn != indirs[num - 1 - level].in_lbn || num < 2)
1406 panic("indiracct_ufs2: botched params");
1408 * We have to expand bread here since it will deadlock looking
1409 * up the block number for any blocks that are not in the cache.
1411 bp = getblk(cancelvp, lbn, fs->fs_bsize, 0, 0, 0);
1412 bp->b_blkno = fsbtodb(fs, blkno);
1413 if ((bp->b_flags & B_CACHE) == 0 &&
1414 (error = readblock(cancelvp, bp, fragstoblks(fs, blkno)))) {
1419 * Account for the block pointers in this indirect block.
1421 last = howmany(remblks, blksperindir);
1422 if (last > NINDIR(fs))
1424 bap = malloc(fs->fs_bsize, M_DEVBUF, M_WAITOK);
1425 bcopy(bp->b_data, (caddr_t)bap, fs->fs_bsize);
1427 error = (*acctfunc)(snapvp, &bap[0], &bap[last], fs,
1428 level == 0 ? rlbn : -1, expungetype);
1429 if (error || level == 0)
1432 * Account for the block pointers in each of the indirect blocks
1433 * in the levels below us.
1435 subblksperindir = blksperindir / NINDIR(fs);
1436 for (lbn++, level--, i = 0; i < last; i++) {
1437 error = indiracct_ufs2(snapvp, cancelvp, level, bap[i], lbn,
1438 rlbn, remblks, subblksperindir, fs, acctfunc, expungetype);
1441 rlbn += blksperindir;
1442 lbn -= blksperindir;
1443 remblks -= blksperindir;
1446 free(bap, M_DEVBUF);
1451 * Do both snap accounting and map accounting.
1454 fullacct_ufs2(vp, oldblkp, lastblkp, fs, lblkno, exptype)
1456 ufs2_daddr_t *oldblkp, *lastblkp;
1459 int exptype; /* BLK_SNAP or BLK_NOCOPY */
1463 if ((error = snapacct_ufs2(vp, oldblkp, lastblkp, fs, lblkno, exptype)))
1465 return (mapacct_ufs2(vp, oldblkp, lastblkp, fs, lblkno, exptype));
1469 * Identify a set of blocks allocated in a snapshot inode.
1472 snapacct_ufs2(vp, oldblkp, lastblkp, fs, lblkno, expungetype)
1474 ufs2_daddr_t *oldblkp, *lastblkp;
1477 int expungetype; /* BLK_SNAP or BLK_NOCOPY */
1479 struct inode *ip = VTOI(vp);
1480 ufs2_daddr_t blkno, *blkp;
1485 for ( ; oldblkp < lastblkp; oldblkp++) {
1487 if (blkno == 0 || blkno == BLK_NOCOPY || blkno == BLK_SNAP)
1489 lbn = fragstoblks(fs, blkno);
1490 if (lbn < UFS_NDADDR) {
1491 blkp = &ip->i_din2->di_db[lbn];
1492 ip->i_flag |= IN_CHANGE | IN_UPDATE;
1494 error = ffs_balloc_ufs2(vp, lblktosize(fs, (off_t)lbn),
1495 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp);
1498 blkp = &((ufs2_daddr_t *)(ibp->b_data))
1499 [(lbn - UFS_NDADDR) % NINDIR(fs)];
1502 * If we are expunging a snapshot vnode and we
1503 * find a block marked BLK_NOCOPY, then it is
1504 * one that has been allocated to this snapshot after
1505 * we took our current snapshot and can be ignored.
1507 if (expungetype == BLK_SNAP && *blkp == BLK_NOCOPY) {
1508 if (lbn >= UFS_NDADDR)
1512 panic("snapacct_ufs2: bad block");
1513 *blkp = expungetype;
1514 if (lbn >= UFS_NDADDR)
1522 * Account for a set of blocks allocated in a snapshot inode.
1525 mapacct_ufs2(vp, oldblkp, lastblkp, fs, lblkno, expungetype)
1527 ufs2_daddr_t *oldblkp, *lastblkp;
1538 inum = ip->i_number;
1543 for ( ; oldblkp < lastblkp; oldblkp++, lblkno++) {
1545 if (blkno == 0 || blkno == BLK_NOCOPY)
1547 if (acctit && expungetype == BLK_SNAP && blkno != BLK_SNAP)
1548 *ip->i_snapblklist++ = lblkno;
1549 if (blkno == BLK_SNAP)
1550 blkno = blkstofrags(fs, lblkno);
1551 ffs_blkfree(ITOUMP(ip), fs, vp, blkno, fs->fs_bsize, inum,
1552 vp->v_type, NULL, SINGLETON_KEY);
1558 * Decrement extra reference on snapshot when last name is removed.
1559 * It will not be freed until the last open reference goes away.
1568 struct snapdata *sn;
1569 struct ufsmount *ump;
1572 * Find snapshot in incore list.
1575 sn = ITODEVVP(ip)->v_rdev->si_snapdata;
1577 TAILQ_FOREACH(xp, &sn->sn_head, i_nextsnap)
1583 printf("ffs_snapgone: lost snapshot vnode %ju\n",
1584 (uintmax_t)ip->i_number);
1586 * Delete snapshot inode from superblock. Keep list dense.
1591 for (snaploc = 0; snaploc < FSMAXSNAP; snaploc++)
1592 if (fs->fs_snapinum[snaploc] == ip->i_number)
1594 if (snaploc < FSMAXSNAP) {
1595 for (snaploc++; snaploc < FSMAXSNAP; snaploc++) {
1596 if (fs->fs_snapinum[snaploc] == 0)
1598 fs->fs_snapinum[snaploc - 1] = fs->fs_snapinum[snaploc];
1600 fs->fs_snapinum[snaploc - 1] = 0;
1606 * Prepare a snapshot file for being removed.
1613 struct vnode *devvp;
1616 ufs2_daddr_t numblks, blkno, dblk;
1617 int error, i, last, loc;
1618 struct snapdata *sn;
1622 devvp = ITODEVVP(ip);
1624 * If active, delete from incore list (this snapshot may
1625 * already have been in the process of being deleted, so
1626 * would not have been active).
1628 * Clear copy-on-write flag if last snapshot.
1631 if (ip->i_nextsnap.tqe_prev != 0) {
1632 sn = devvp->v_rdev->si_snapdata;
1633 TAILQ_REMOVE(&sn->sn_head, ip, i_nextsnap);
1634 ip->i_nextsnap.tqe_prev = 0;
1636 lockmgr(&vp->v_lock, LK_EXCLUSIVE, NULL);
1637 for (i = 0; i < sn->sn_lock.lk_recurse; i++)
1638 lockmgr(&vp->v_lock, LK_EXCLUSIVE, NULL);
1639 KASSERT(vp->v_vnlock == &sn->sn_lock,
1640 ("ffs_snapremove: lost lock mutation"));
1641 vp->v_vnlock = &vp->v_lock;
1643 while (sn->sn_lock.lk_recurse > 0)
1644 lockmgr(&sn->sn_lock, LK_RELEASE, NULL);
1645 lockmgr(&sn->sn_lock, LK_RELEASE, NULL);
1646 try_free_snapdata(devvp);
1650 * Clear all BLK_NOCOPY fields. Pass any block claims to other
1651 * snapshots that want them (see ffs_snapblkfree below).
1653 for (blkno = 1; blkno < UFS_NDADDR; blkno++) {
1654 dblk = DIP(ip, i_db[blkno]);
1657 if (dblk == BLK_NOCOPY || dblk == BLK_SNAP)
1658 DIP_SET(ip, i_db[blkno], 0);
1659 else if ((dblk == blkstofrags(fs, blkno) &&
1660 ffs_snapblkfree(fs, ITODEVVP(ip), dblk, fs->fs_bsize,
1661 ip->i_number, vp->v_type, NULL))) {
1662 DIP_SET(ip, i_blocks, DIP(ip, i_blocks) -
1663 btodb(fs->fs_bsize));
1664 DIP_SET(ip, i_db[blkno], 0);
1667 numblks = howmany(ip->i_size, fs->fs_bsize);
1668 for (blkno = UFS_NDADDR; blkno < numblks; blkno += NINDIR(fs)) {
1669 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)blkno),
1670 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp);
1673 if (fs->fs_size - blkno > NINDIR(fs))
1676 last = fs->fs_size - blkno;
1677 for (loc = 0; loc < last; loc++) {
1678 if (I_IS_UFS1(ip)) {
1679 dblk = ((ufs1_daddr_t *)(ibp->b_data))[loc];
1682 if (dblk == BLK_NOCOPY || dblk == BLK_SNAP)
1683 ((ufs1_daddr_t *)(ibp->b_data))[loc]= 0;
1684 else if ((dblk == blkstofrags(fs, blkno) &&
1685 ffs_snapblkfree(fs, ITODEVVP(ip), dblk,
1686 fs->fs_bsize, ip->i_number, vp->v_type,
1688 ip->i_din1->di_blocks -=
1689 btodb(fs->fs_bsize);
1690 ((ufs1_daddr_t *)(ibp->b_data))[loc]= 0;
1694 dblk = ((ufs2_daddr_t *)(ibp->b_data))[loc];
1697 if (dblk == BLK_NOCOPY || dblk == BLK_SNAP)
1698 ((ufs2_daddr_t *)(ibp->b_data))[loc] = 0;
1699 else if ((dblk == blkstofrags(fs, blkno) &&
1700 ffs_snapblkfree(fs, ITODEVVP(ip), dblk,
1701 fs->fs_bsize, ip->i_number, vp->v_type, NULL))) {
1702 ip->i_din2->di_blocks -= btodb(fs->fs_bsize);
1703 ((ufs2_daddr_t *)(ibp->b_data))[loc] = 0;
1709 * Clear snapshot flag and drop reference.
1711 ip->i_flags &= ~SF_SNAPSHOT;
1712 DIP_SET(ip, i_flags, ip->i_flags);
1713 ip->i_flag |= IN_CHANGE | IN_UPDATE;
1715 * The dirtied indirects must be written out before
1716 * softdep_setup_freeblocks() is called. Otherwise indir_trunc()
1717 * may find indirect pointers using the magic BLK_* values.
1719 if (DOINGSOFTDEP(vp))
1720 ffs_syncvnode(vp, MNT_WAIT, 0);
1723 * Reenable disk quotas for ex-snapshot file.
1725 if (!getinoquota(ip))
1726 (void) chkdq(ip, DIP(ip, i_blocks), KERNCRED, FORCE);
1731 * Notification that a block is being freed. Return zero if the free
1732 * should be allowed to proceed. Return non-zero if the snapshot file
1733 * wants to claim the block. The block will be claimed if it is an
1734 * uncopied part of one of the snapshots. It will be freed if it is
1735 * either a BLK_NOCOPY or has already been copied in all of the snapshots.
1736 * If a fragment is being freed, then all snapshots that care about
1737 * it must make a copy since a snapshot file can only claim full sized
1738 * blocks. Note that if more than one snapshot file maps the block,
1739 * we can pick one at random to claim it. Since none of the snapshots
1740 * can change, we are assurred that they will all see the same unmodified
1741 * image. When deleting a snapshot file (see ffs_snapremove above), we
1742 * must push any of these claimed blocks to one of the other snapshots
1743 * that maps it. These claimed blocks are easily identified as they will
1744 * have a block number equal to their logical block number within the
1745 * snapshot. A copied block can never have this property because they
1746 * must always have been allocated from a BLK_NOCOPY location.
1749 ffs_snapblkfree(fs, devvp, bno, size, inum, vtype, wkhd)
1751 struct vnode *devvp;
1756 struct workhead *wkhd;
1758 struct buf *ibp, *cbp, *savedcbp = NULL;
1759 struct thread *td = curthread;
1761 struct vnode *vp = NULL;
1764 int indiroff = 0, error = 0, claimedblk = 0;
1765 struct snapdata *sn;
1767 lbn = fragstoblks(fs, bno);
1770 sn = devvp->v_rdev->si_snapdata;
1775 if (lockmgr(&sn->sn_lock, LK_INTERLOCK | LK_EXCLUSIVE | LK_SLEEPFAIL,
1776 VI_MTX(devvp)) != 0)
1778 TAILQ_FOREACH(ip, &sn->sn_head, i_nextsnap) {
1780 if (DOINGSOFTDEP(vp))
1781 softdep_prealloc(vp, MNT_WAIT);
1783 * Lookup block being written.
1785 if (lbn < UFS_NDADDR) {
1786 blkno = DIP(ip, i_db[lbn]);
1788 td->td_pflags |= TDP_COWINPROGRESS;
1789 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)lbn),
1790 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp);
1791 td->td_pflags &= ~TDP_COWINPROGRESS;
1794 indiroff = (lbn - UFS_NDADDR) % NINDIR(fs);
1796 blkno=((ufs1_daddr_t *)(ibp->b_data))[indiroff];
1798 blkno=((ufs2_daddr_t *)(ibp->b_data))[indiroff];
1801 * Check to see if block needs to be copied.
1805 * A block that we map is being freed. If it has not
1806 * been claimed yet, we will claim or copy it (below).
1809 } else if (blkno == BLK_SNAP) {
1811 * No previous snapshot claimed the block,
1812 * so it will be freed and become a BLK_NOCOPY
1813 * (don't care) for us.
1816 panic("snapblkfree: inconsistent block type");
1817 if (lbn < UFS_NDADDR) {
1818 DIP_SET(ip, i_db[lbn], BLK_NOCOPY);
1819 ip->i_flag |= IN_CHANGE | IN_UPDATE;
1820 } else if (I_IS_UFS1(ip)) {
1821 ((ufs1_daddr_t *)(ibp->b_data))[indiroff] =
1825 ((ufs2_daddr_t *)(ibp->b_data))[indiroff] =
1830 } else /* BLK_NOCOPY or default */ {
1832 * If the snapshot has already copied the block
1833 * (default), or does not care about the block,
1836 if (lbn >= UFS_NDADDR)
1841 * If this is a full size block, we will just grab it
1842 * and assign it to the snapshot inode. Otherwise we
1843 * will proceed to copy it. See explanation for this
1844 * routine as to why only a single snapshot needs to
1847 if (size == fs->fs_bsize) {
1850 printf("%s %ju lbn %jd from inum %ju\n",
1851 "Grabonremove: snapino",
1852 (uintmax_t)ip->i_number,
1853 (intmax_t)lbn, (uintmax_t)inum);
1856 * If journaling is tracking this write we must add
1857 * the work to the inode or indirect being written.
1860 if (lbn < UFS_NDADDR)
1861 softdep_inode_append(ip,
1862 curthread->td_ucred, wkhd);
1864 softdep_buf_append(ibp, wkhd);
1866 if (lbn < UFS_NDADDR) {
1867 DIP_SET(ip, i_db[lbn], bno);
1868 } else if (I_IS_UFS1(ip)) {
1869 ((ufs1_daddr_t *)(ibp->b_data))[indiroff] = bno;
1872 ((ufs2_daddr_t *)(ibp->b_data))[indiroff] = bno;
1875 DIP_SET(ip, i_blocks, DIP(ip, i_blocks) + btodb(size));
1876 ip->i_flag |= IN_CHANGE | IN_UPDATE;
1877 lockmgr(vp->v_vnlock, LK_RELEASE, NULL);
1880 if (lbn >= UFS_NDADDR)
1883 * Allocate the block into which to do the copy. Note that this
1884 * allocation will never require any additional allocations for
1885 * the snapshot inode.
1887 td->td_pflags |= TDP_COWINPROGRESS;
1888 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)lbn),
1889 fs->fs_bsize, KERNCRED, 0, &cbp);
1890 td->td_pflags &= ~TDP_COWINPROGRESS;
1895 printf("%s%ju lbn %jd %s %ju size %ld to blkno %jd\n",
1896 "Copyonremove: snapino ", (uintmax_t)ip->i_number,
1897 (intmax_t)lbn, "for inum", (uintmax_t)inum, size,
1898 (intmax_t)cbp->b_blkno);
1901 * If we have already read the old block contents, then
1902 * simply copy them to the new block. Note that we need
1903 * to synchronously write snapshots that have not been
1904 * unlinked, and hence will be visible after a crash,
1905 * to ensure their integrity. At a minimum we ensure the
1906 * integrity of the filesystem metadata, but use the
1907 * dopersistence sysctl-setable flag to decide on the
1908 * persistence needed for file content data.
1910 if (savedcbp != NULL) {
1911 bcopy(savedcbp->b_data, cbp->b_data, fs->fs_bsize);
1913 if ((vtype == VDIR || dopersistence) &&
1915 (void) ffs_syncvnode(vp, MNT_WAIT, NO_INO_UPDT);
1919 * Otherwise, read the old block contents into the buffer.
1921 if ((error = readblock(vp, cbp, lbn)) != 0) {
1922 bzero(cbp->b_data, fs->fs_bsize);
1924 if ((vtype == VDIR || dopersistence) &&
1926 (void) ffs_syncvnode(vp, MNT_WAIT, NO_INO_UPDT);
1932 * Note that we need to synchronously write snapshots that
1933 * have not been unlinked, and hence will be visible after
1934 * a crash, to ensure their integrity. At a minimum we
1935 * ensure the integrity of the filesystem metadata, but
1936 * use the dopersistence sysctl-setable flag to decide on
1937 * the persistence needed for file content data.
1940 vp = savedcbp->b_vp;
1942 if ((vtype == VDIR || dopersistence) &&
1943 VTOI(vp)->i_effnlink > 0)
1944 (void) ffs_syncvnode(vp, MNT_WAIT, NO_INO_UPDT);
1947 * If we have been unable to allocate a block in which to do
1948 * the copy, then return non-zero so that the fragment will
1949 * not be freed. Although space will be lost, the snapshot
1950 * will stay consistent.
1952 if (error != 0 && wkhd != NULL)
1953 softdep_freework(wkhd);
1954 lockmgr(&sn->sn_lock, LK_RELEASE, NULL);
1959 * Associate snapshot files when mounting.
1962 ffs_snapshot_mount(mp)
1965 struct ufsmount *ump = VFSTOUFS(mp);
1966 struct vnode *devvp = ump->um_devvp;
1967 struct fs *fs = ump->um_fs;
1968 struct thread *td = curthread;
1969 struct snapdata *sn;
1971 struct vnode *lastvp;
1977 daddr_t snaplistsize;
1978 int error, snaploc, loc;
1981 * XXX The following needs to be set before ffs_truncate or
1982 * VOP_READ can be called.
1984 mp->mnt_stat.f_iosize = fs->fs_bsize;
1986 * Process each snapshot listed in the superblock.
1991 for (snaploc = 0; snaploc < FSMAXSNAP; snaploc++) {
1992 if (fs->fs_snapinum[snaploc] == 0)
1994 if ((error = ffs_vget(mp, fs->fs_snapinum[snaploc],
1995 LK_EXCLUSIVE, &vp)) != 0){
1996 printf("ffs_snapshot_mount: vget failed %d\n", error);
2000 if (!IS_SNAPSHOT(ip) || ip->i_size ==
2001 lblktosize(fs, howmany(fs->fs_size, fs->fs_frag))) {
2002 if (!IS_SNAPSHOT(ip)) {
2003 reason = "non-snapshot";
2005 reason = "old format snapshot";
2006 (void)ffs_truncate(vp, (off_t)0, 0, NOCRED);
2007 (void)ffs_syncvnode(vp, MNT_WAIT, 0);
2009 printf("ffs_snapshot_mount: %s inode %d\n",
2010 reason, fs->fs_snapinum[snaploc]);
2013 for (loc = snaploc + 1; loc < FSMAXSNAP; loc++) {
2014 if (fs->fs_snapinum[loc] == 0)
2016 fs->fs_snapinum[loc - 1] = fs->fs_snapinum[loc];
2018 fs->fs_snapinum[loc - 1] = 0;
2023 * Acquire a lock on the snapdata structure, creating it if
2026 sn = ffs_snapdata_acquire(devvp);
2028 * Change vnode to use shared snapshot lock instead of the
2029 * original private lock.
2031 vp->v_vnlock = &sn->sn_lock;
2032 lockmgr(&vp->v_lock, LK_RELEASE, NULL);
2034 * Link it onto the active snapshot list.
2037 if (ip->i_nextsnap.tqe_prev != 0)
2038 panic("ffs_snapshot_mount: %ju already on list",
2039 (uintmax_t)ip->i_number);
2041 TAILQ_INSERT_TAIL(&sn->sn_head, ip, i_nextsnap);
2042 vp->v_vflag |= VV_SYSTEM;
2049 * No usable snapshots found.
2051 if (sn == NULL || vp == NULL)
2054 * Allocate the space for the block hints list. We always want to
2055 * use the list from the newest snapshot.
2057 auio.uio_iov = &aiov;
2058 auio.uio_iovcnt = 1;
2059 aiov.iov_base = (void *)&snaplistsize;
2060 aiov.iov_len = sizeof(snaplistsize);
2061 auio.uio_resid = aiov.iov_len;
2063 lblktosize(fs, howmany(fs->fs_size, fs->fs_frag));
2064 auio.uio_segflg = UIO_SYSSPACE;
2065 auio.uio_rw = UIO_READ;
2067 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
2068 if ((error = VOP_READ(vp, &auio, IO_UNIT, td->td_ucred)) != 0) {
2069 printf("ffs_snapshot_mount: read_1 failed %d\n", error);
2073 snapblklist = malloc(snaplistsize * sizeof(daddr_t),
2074 M_UFSMNT, M_WAITOK);
2075 auio.uio_iovcnt = 1;
2076 aiov.iov_base = snapblklist;
2077 aiov.iov_len = snaplistsize * sizeof (daddr_t);
2078 auio.uio_resid = aiov.iov_len;
2079 auio.uio_offset -= sizeof(snaplistsize);
2080 if ((error = VOP_READ(vp, &auio, IO_UNIT, td->td_ucred)) != 0) {
2081 printf("ffs_snapshot_mount: read_2 failed %d\n", error);
2083 free(snapblklist, M_UFSMNT);
2088 ASSERT_VOP_LOCKED(devvp, "ffs_snapshot_mount");
2089 sn->sn_listsize = snaplistsize;
2090 sn->sn_blklist = (daddr_t *)snapblklist;
2091 devvp->v_vflag |= VV_COPYONWRITE;
2096 * Disassociate snapshot files when unmounting.
2099 ffs_snapshot_unmount(mp)
2102 struct vnode *devvp = VFSTOUFS(mp)->um_devvp;
2103 struct snapdata *sn;
2108 sn = devvp->v_rdev->si_snapdata;
2109 while (sn != NULL && (xp = TAILQ_FIRST(&sn->sn_head)) != NULL) {
2111 TAILQ_REMOVE(&sn->sn_head, xp, i_nextsnap);
2112 xp->i_nextsnap.tqe_prev = 0;
2113 lockmgr(&sn->sn_lock, LK_INTERLOCK | LK_EXCLUSIVE,
2115 lockmgr(&vp->v_lock, LK_EXCLUSIVE, NULL);
2116 KASSERT(vp->v_vnlock == &sn->sn_lock,
2117 ("ffs_snapshot_unmount: lost lock mutation"));
2118 vp->v_vnlock = &vp->v_lock;
2119 lockmgr(&vp->v_lock, LK_RELEASE, NULL);
2120 lockmgr(&sn->sn_lock, LK_RELEASE, NULL);
2121 if (xp->i_effnlink > 0)
2124 sn = devvp->v_rdev->si_snapdata;
2126 try_free_snapdata(devvp);
2127 ASSERT_VOP_LOCKED(devvp, "ffs_snapshot_unmount");
2131 * Check the buffer block to be belong to device buffer that shall be
2132 * locked after snaplk. devvp shall be locked on entry, and will be
2133 * leaved locked upon exit.
2136 ffs_bp_snapblk(devvp, bp)
2137 struct vnode *devvp;
2140 struct snapdata *sn;
2142 ufs2_daddr_t lbn, *snapblklist;
2143 int lower, upper, mid;
2145 ASSERT_VI_LOCKED(devvp, "ffs_bp_snapblk");
2146 KASSERT(devvp->v_type == VCHR, ("Not a device %p", devvp));
2147 sn = devvp->v_rdev->si_snapdata;
2148 if (sn == NULL || TAILQ_FIRST(&sn->sn_head) == NULL)
2150 fs = ITOFS(TAILQ_FIRST(&sn->sn_head));
2151 lbn = fragstoblks(fs, dbtofsb(fs, bp->b_blkno));
2152 snapblklist = sn->sn_blklist;
2153 upper = sn->sn_listsize - 1;
2155 while (lower <= upper) {
2156 mid = (lower + upper) / 2;
2157 if (snapblklist[mid] == lbn)
2159 if (snapblklist[mid] < lbn)
2175 struct vnode *vp, *devvp;
2179 if (bo->bo_dirty.bv_cnt <= dirtybufthresh)
2184 devvp = bo2vnode(bo);
2185 KASSERT(vp == devvp, ("devvp != vp %p %p", bo, bp));
2188 bp_bdskip = ffs_bp_snapblk(devvp, bp);
2192 if (bo->bo_dirty.bv_cnt > dirtybufthresh + 10 && !bp_bdskip) {
2193 (void) VOP_FSYNC(vp, MNT_NOWAIT, td);
2198 * Try to find a buffer to flush.
2200 TAILQ_FOREACH(nbp, &bo->bo_dirty.bv_hd, b_bobufs) {
2201 if ((nbp->b_vflags & BV_BKGRDINPROG) ||
2203 LK_EXCLUSIVE | LK_NOWAIT, NULL))
2206 panic("bdwrite: found ourselves");
2209 * Don't countdeps with the bo lock
2212 if (buf_countdeps(nbp, 0)) {
2219 if (!ffs_bp_snapblk(vp, nbp)) {
2227 if (nbp->b_flags & B_CLUSTEROK) {
2228 vfs_bio_awrite(nbp);
2233 dirtybufferflushes++;
2242 * Check for need to copy block that is about to be written,
2243 * copying the block if necessary.
2246 ffs_copyonwrite(devvp, bp)
2247 struct vnode *devvp;
2250 struct snapdata *sn;
2251 struct buf *ibp, *cbp, *savedcbp = NULL;
2252 struct thread *td = curthread;
2255 struct vnode *vp = NULL;
2256 ufs2_daddr_t lbn, blkno, *snapblklist;
2257 int lower, upper, mid, indiroff, error = 0;
2258 int launched_async_io, prev_norunningbuf;
2259 long saved_runningbufspace;
2261 if (devvp != bp->b_vp && IS_SNAPSHOT(VTOI(bp->b_vp)))
2262 return (0); /* Update on a snapshot file */
2263 if (td->td_pflags & TDP_COWINPROGRESS)
2264 panic("ffs_copyonwrite: recursive call");
2266 * First check to see if it is in the preallocated list.
2267 * By doing this check we avoid several potential deadlocks.
2270 sn = devvp->v_rdev->si_snapdata;
2272 TAILQ_EMPTY(&sn->sn_head)) {
2274 return (0); /* No snapshot */
2276 ip = TAILQ_FIRST(&sn->sn_head);
2278 lbn = fragstoblks(fs, dbtofsb(fs, bp->b_blkno));
2279 snapblklist = sn->sn_blklist;
2280 upper = sn->sn_listsize - 1;
2282 while (lower <= upper) {
2283 mid = (lower + upper) / 2;
2284 if (snapblklist[mid] == lbn)
2286 if (snapblklist[mid] < lbn)
2291 if (lower <= upper) {
2295 launched_async_io = 0;
2296 prev_norunningbuf = td->td_pflags & TDP_NORUNNINGBUF;
2298 * Since I/O on bp isn't yet in progress and it may be blocked
2299 * for a long time waiting on snaplk, back it out of
2300 * runningbufspace, possibly waking other threads waiting for space.
2302 saved_runningbufspace = bp->b_runningbufspace;
2303 if (saved_runningbufspace != 0)
2304 runningbufwakeup(bp);
2306 * Not in the precomputed list, so check the snapshots.
2308 while (lockmgr(&sn->sn_lock, LK_INTERLOCK | LK_EXCLUSIVE | LK_SLEEPFAIL,
2309 VI_MTX(devvp)) != 0) {
2311 sn = devvp->v_rdev->si_snapdata;
2313 TAILQ_EMPTY(&sn->sn_head)) {
2315 if (saved_runningbufspace != 0) {
2316 bp->b_runningbufspace = saved_runningbufspace;
2317 atomic_add_long(&runningbufspace,
2318 bp->b_runningbufspace);
2320 return (0); /* Snapshot gone */
2323 TAILQ_FOREACH(ip, &sn->sn_head, i_nextsnap) {
2325 if (DOINGSOFTDEP(vp))
2326 softdep_prealloc(vp, MNT_WAIT);
2328 * We ensure that everything of our own that needs to be
2329 * copied will be done at the time that ffs_snapshot is
2330 * called. Thus we can skip the check here which can
2331 * deadlock in doing the lookup in UFS_BALLOC.
2336 * Check to see if block needs to be copied. We do not have
2337 * to hold the snapshot lock while doing this lookup as it
2338 * will never require any additional allocations for the
2341 if (lbn < UFS_NDADDR) {
2342 blkno = DIP(ip, i_db[lbn]);
2344 td->td_pflags |= TDP_COWINPROGRESS | TDP_NORUNNINGBUF;
2345 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)lbn),
2346 fs->fs_bsize, KERNCRED, BA_METAONLY, &ibp);
2347 td->td_pflags &= ~TDP_COWINPROGRESS;
2350 indiroff = (lbn - UFS_NDADDR) % NINDIR(fs);
2352 blkno=((ufs1_daddr_t *)(ibp->b_data))[indiroff];
2354 blkno=((ufs2_daddr_t *)(ibp->b_data))[indiroff];
2358 if (blkno == BLK_SNAP && bp->b_lblkno >= 0)
2359 panic("ffs_copyonwrite: bad copy block");
2364 * Allocate the block into which to do the copy. Since
2365 * multiple processes may all try to copy the same block,
2366 * we have to recheck our need to do a copy if we sleep
2367 * waiting for the lock.
2369 * Because all snapshots on a filesystem share a single
2370 * lock, we ensure that we will never be in competition
2371 * with another process to allocate a block.
2373 td->td_pflags |= TDP_COWINPROGRESS | TDP_NORUNNINGBUF;
2374 error = UFS_BALLOC(vp, lblktosize(fs, (off_t)lbn),
2375 fs->fs_bsize, KERNCRED, 0, &cbp);
2376 td->td_pflags &= ~TDP_COWINPROGRESS;
2381 printf("Copyonwrite: snapino %ju lbn %jd for ",
2382 (uintmax_t)ip->i_number, (intmax_t)lbn);
2383 if (bp->b_vp == devvp)
2384 printf("fs metadata");
2387 (uintmax_t)VTOI(bp->b_vp)->i_number);
2388 printf(" lblkno %jd to blkno %jd\n",
2389 (intmax_t)bp->b_lblkno, (intmax_t)cbp->b_blkno);
2393 * If we have already read the old block contents, then
2394 * simply copy them to the new block. Note that we need
2395 * to synchronously write snapshots that have not been
2396 * unlinked, and hence will be visible after a crash,
2397 * to ensure their integrity. At a minimum we ensure the
2398 * integrity of the filesystem metadata, but use the
2399 * dopersistence sysctl-setable flag to decide on the
2400 * persistence needed for file content data.
2402 if (savedcbp != NULL) {
2403 bcopy(savedcbp->b_data, cbp->b_data, fs->fs_bsize);
2405 if ((devvp == bp->b_vp || bp->b_vp->v_type == VDIR ||
2406 dopersistence) && ip->i_effnlink > 0)
2407 (void) ffs_syncvnode(vp, MNT_WAIT, NO_INO_UPDT);
2409 launched_async_io = 1;
2413 * Otherwise, read the old block contents into the buffer.
2415 if ((error = readblock(vp, cbp, lbn)) != 0) {
2416 bzero(cbp->b_data, fs->fs_bsize);
2418 if ((devvp == bp->b_vp || bp->b_vp->v_type == VDIR ||
2419 dopersistence) && ip->i_effnlink > 0)
2420 (void) ffs_syncvnode(vp, MNT_WAIT, NO_INO_UPDT);
2422 launched_async_io = 1;
2428 * Note that we need to synchronously write snapshots that
2429 * have not been unlinked, and hence will be visible after
2430 * a crash, to ensure their integrity. At a minimum we
2431 * ensure the integrity of the filesystem metadata, but
2432 * use the dopersistence sysctl-setable flag to decide on
2433 * the persistence needed for file content data.
2436 vp = savedcbp->b_vp;
2438 if ((devvp == bp->b_vp || bp->b_vp->v_type == VDIR ||
2439 dopersistence) && VTOI(vp)->i_effnlink > 0)
2440 (void) ffs_syncvnode(vp, MNT_WAIT, NO_INO_UPDT);
2442 launched_async_io = 1;
2444 lockmgr(vp->v_vnlock, LK_RELEASE, NULL);
2445 td->td_pflags = (td->td_pflags & ~TDP_NORUNNINGBUF) |
2447 if (launched_async_io && (td->td_pflags & TDP_NORUNNINGBUF) == 0)
2448 waitrunningbufspace();
2450 * I/O on bp will now be started, so count it in runningbufspace.
2452 if (saved_runningbufspace != 0) {
2453 bp->b_runningbufspace = saved_runningbufspace;
2454 atomic_add_long(&runningbufspace, bp->b_runningbufspace);
2460 * sync snapshots to force freework records waiting on snapshots to claim
2464 ffs_sync_snap(mp, waitfor)
2468 struct snapdata *sn;
2469 struct vnode *devvp;
2473 devvp = VFSTOUFS(mp)->um_devvp;
2474 if ((devvp->v_vflag & VV_COPYONWRITE) == 0)
2478 sn = devvp->v_rdev->si_snapdata;
2483 if (lockmgr(&sn->sn_lock,
2484 LK_INTERLOCK | LK_EXCLUSIVE | LK_SLEEPFAIL,
2485 VI_MTX(devvp)) == 0)
2488 TAILQ_FOREACH(ip, &sn->sn_head, i_nextsnap) {
2490 ffs_syncvnode(vp, waitfor, NO_INO_UPDT);
2492 lockmgr(&sn->sn_lock, LK_RELEASE, NULL);
2496 * Read the specified block into the given buffer.
2497 * Much of this boiler-plate comes from bwrite().
2500 readblock(vp, bp, lbn)
2512 bip = g_alloc_bio();
2513 bip->bio_cmd = BIO_READ;
2514 bip->bio_offset = dbtob(fsbtodb(fs, blkstofrags(fs, lbn)));
2515 bip->bio_data = bp->b_data;
2516 bip->bio_length = bp->b_bcount;
2517 bip->bio_done = NULL;
2519 g_io_request(bip, ITODEVVP(ip)->v_bufobj.bo_private);
2520 bp->b_error = biowait(bip, "snaprdb");
2522 return (bp->b_error);
2528 * Process file deletes that were deferred by ufs_inactive() due to
2529 * the file system being suspended. Transfer IN_LAZYACCESS into
2530 * IN_MODIFIED for vnodes that were accessed during suspension.
2533 process_deferred_inactive(struct mount *mp)
2535 struct vnode *vp, *mvp;
2541 (void) vn_start_secondary_write(NULL, &mp, V_WAIT);
2543 MNT_VNODE_FOREACH_ALL(vp, mp, mvp) {
2545 * IN_LAZYACCESS is checked here without holding any
2546 * vnode lock, but this flag is set only while holding
2549 if (vp->v_type == VNON ||
2550 ((VTOI(vp)->i_flag & IN_LAZYACCESS) == 0 &&
2551 ((vp->v_iflag & VI_OWEINACT) == 0 || vp->v_usecount > 0))) {
2556 error = vn_lock(vp, LK_EXCLUSIVE | LK_INTERLOCK);
2559 if (error == ENOENT)
2560 continue; /* vnode recycled */
2561 MNT_VNODE_FOREACH_ALL_ABORT(mp, mvp);
2565 if ((ip->i_flag & IN_LAZYACCESS) != 0) {
2566 ip->i_flag &= ~IN_LAZYACCESS;
2567 ip->i_flag |= IN_MODIFIED;
2570 if ((vp->v_iflag & VI_OWEINACT) == 0 || vp->v_usecount > 0) {
2577 VNASSERT((vp->v_iflag & VI_OWEINACT) == 0, vp,
2578 ("process_deferred_inactive: got VI_OWEINACT"));
2583 vn_finished_secondary_write(mp);
2586 #ifndef NO_FFS_SNAPSHOT
2588 static struct snapdata *
2589 ffs_snapdata_alloc(void)
2591 struct snapdata *sn;
2594 * Fetch a snapdata from the free list if there is one available.
2596 mtx_lock(&snapfree_lock);
2597 sn = LIST_FIRST(&snapfree);
2599 LIST_REMOVE(sn, sn_link);
2600 mtx_unlock(&snapfree_lock);
2604 * If there were no free snapdatas allocate one.
2606 sn = malloc(sizeof *sn, M_UFSMNT, M_WAITOK | M_ZERO);
2607 TAILQ_INIT(&sn->sn_head);
2608 lockinit(&sn->sn_lock, PVFS, "snaplk", VLKTIMEOUT,
2609 LK_CANRECURSE | LK_NOSHARE);
2614 * The snapdata is never freed because we can not be certain that
2615 * there are no threads sleeping on the snap lock. Persisting
2616 * them permanently avoids costly synchronization in ffs_lock().
2619 ffs_snapdata_free(struct snapdata *sn)
2621 mtx_lock(&snapfree_lock);
2622 LIST_INSERT_HEAD(&snapfree, sn, sn_link);
2623 mtx_unlock(&snapfree_lock);
2626 /* Try to free snapdata associated with devvp */
2628 try_free_snapdata(struct vnode *devvp)
2630 struct snapdata *sn;
2631 ufs2_daddr_t *snapblklist;
2633 ASSERT_VI_LOCKED(devvp, "try_free_snapdata");
2634 sn = devvp->v_rdev->si_snapdata;
2636 if (sn == NULL || TAILQ_FIRST(&sn->sn_head) != NULL ||
2637 (devvp->v_vflag & VV_COPYONWRITE) == 0) {
2642 devvp->v_rdev->si_snapdata = NULL;
2643 devvp->v_vflag &= ~VV_COPYONWRITE;
2644 lockmgr(&sn->sn_lock, LK_DRAIN|LK_INTERLOCK, VI_MTX(devvp));
2645 snapblklist = sn->sn_blklist;
2646 sn->sn_blklist = NULL;
2647 sn->sn_listsize = 0;
2648 lockmgr(&sn->sn_lock, LK_RELEASE, NULL);
2649 if (snapblklist != NULL)
2650 free(snapblklist, M_UFSMNT);
2651 ffs_snapdata_free(sn);
2654 static struct snapdata *
2655 ffs_snapdata_acquire(struct vnode *devvp)
2657 struct snapdata *nsn, *sn;
2661 * Allocate a free snapdata. This is done before acquiring the
2662 * devvp lock to avoid allocation while the devvp interlock is
2665 nsn = ffs_snapdata_alloc();
2669 sn = devvp->v_rdev->si_snapdata;
2672 * This is the first snapshot on this
2673 * filesystem and we use our pre-allocated
2674 * snapdata. Publish sn with the sn_lock
2675 * owned by us, to avoid the race.
2677 error = lockmgr(&nsn->sn_lock, LK_EXCLUSIVE |
2680 panic("leaked sn, lockmgr error %d", error);
2681 sn = devvp->v_rdev->si_snapdata = nsn;
2688 * There is a snapshots which already exists on this
2689 * filesystem, grab a reference to the common lock.
2691 error = lockmgr(&sn->sn_lock, LK_INTERLOCK |
2692 LK_EXCLUSIVE | LK_SLEEPFAIL, VI_MTX(devvp));
2698 * Free any unused snapdata.
2701 ffs_snapdata_free(nsn);