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