xref: /freebsd/sys/ufs/ffs/ffs_inode.c (revision 81ad626541db97eb356e2c1d4a20eb2a26a766ab)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1982, 1986, 1989, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  *
31  *	@(#)ffs_inode.c	8.13 (Berkeley) 4/21/95
32  */
33 
34 #include <sys/cdefs.h>
35 __FBSDID("$FreeBSD$");
36 
37 #include "opt_ufs.h"
38 #include "opt_quota.h"
39 
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/bio.h>
43 #include <sys/buf.h>
44 #include <sys/malloc.h>
45 #include <sys/mount.h>
46 #include <sys/proc.h>
47 #include <sys/racct.h>
48 #include <sys/random.h>
49 #include <sys/resourcevar.h>
50 #include <sys/rwlock.h>
51 #include <sys/stat.h>
52 #include <sys/vmmeter.h>
53 #include <sys/vnode.h>
54 
55 #include <vm/vm.h>
56 #include <vm/vm_extern.h>
57 #include <vm/vm_object.h>
58 
59 #include <ufs/ufs/extattr.h>
60 #include <ufs/ufs/quota.h>
61 #include <ufs/ufs/ufsmount.h>
62 #include <ufs/ufs/inode.h>
63 #include <ufs/ufs/dir.h>
64 #ifdef UFS_DIRHASH
65 #include <ufs/ufs/dirhash.h>
66 #endif
67 #include <ufs/ufs/ufs_extern.h>
68 
69 #include <ufs/ffs/fs.h>
70 #include <ufs/ffs/ffs_extern.h>
71 
72 static int ffs_indirtrunc(struct inode *, ufs2_daddr_t, ufs2_daddr_t,
73 	    ufs2_daddr_t, int, ufs2_daddr_t *);
74 
75 static void
76 ffs_inode_bwrite(struct vnode *vp, struct buf *bp, int flags)
77 {
78 	if ((flags & IO_SYNC) != 0)
79 		bwrite(bp);
80 	else if (DOINGASYNC(vp))
81 		bdwrite(bp);
82 	else
83 		bawrite(bp);
84 }
85 
86 /*
87  * Update the access, modified, and inode change times as specified by the
88  * IN_ACCESS, IN_UPDATE, and IN_CHANGE flags respectively.  Write the inode
89  * to disk if the IN_MODIFIED flag is set (it may be set initially, or by
90  * the timestamp update).  The IN_LAZYMOD flag is set to force a write
91  * later if not now.  The IN_LAZYACCESS is set instead of IN_MODIFIED if the fs
92  * is currently being suspended (or is suspended) and vnode has been accessed.
93  * If we write now, then clear IN_MODIFIED, IN_LAZYACCESS and IN_LAZYMOD to
94  * reflect the presumably successful write, and if waitfor is set, then wait
95  * for the write to complete.
96  */
97 int
98 ffs_update(struct vnode *vp, int waitfor)
99 {
100 	struct fs *fs;
101 	struct buf *bp;
102 	struct inode *ip;
103 	daddr_t bn;
104 	int flags, error;
105 
106 	ASSERT_VOP_ELOCKED(vp, "ffs_update");
107 	ufs_itimes(vp);
108 	ip = VTOI(vp);
109 	if ((ip->i_flag & IN_MODIFIED) == 0 && waitfor == 0)
110 		return (0);
111 	ip->i_flag &= ~(IN_LAZYACCESS | IN_LAZYMOD | IN_MODIFIED);
112 	/*
113 	 * The IN_SIZEMOD and IN_IBLKDATA flags indicate changes to the
114 	 * file size and block pointer fields in the inode. When these
115 	 * fields have been changed, the fsync() and fsyncdata() system
116 	 * calls must write the inode to ensure their semantics that the
117 	 * file is on stable store.
118 	 *
119 	 * The IN_SIZEMOD and IN_IBLKDATA flags cannot be cleared until
120 	 * a synchronous write of the inode is done. If they are cleared
121 	 * on an asynchronous write, then the inode may not yet have been
122 	 * written to the disk when an fsync() or fsyncdata() call is done.
123 	 * Absent these flags, these calls would not know that they needed
124 	 * to write the inode. Thus, these flags only can be cleared on
125 	 * synchronous writes of the inode. Since the inode will be locked
126 	 * for the duration of the I/O that writes it to disk, no fsync()
127 	 * or fsyncdata() will be able to run before the on-disk inode
128 	 * is complete.
129 	 */
130 	if (waitfor)
131 		ip->i_flag &= ~(IN_SIZEMOD | IN_IBLKDATA);
132 	fs = ITOFS(ip);
133 	if (fs->fs_ronly)
134 		return (0);
135 	/*
136 	 * If we are updating a snapshot and another process is currently
137 	 * writing the buffer containing the inode for this snapshot then
138 	 * a deadlock can occur when it tries to check the snapshot to see
139 	 * if that block needs to be copied. Thus when updating a snapshot
140 	 * we check to see if the buffer is already locked, and if it is
141 	 * we drop the snapshot lock until the buffer has been written
142 	 * and is available to us. We have to grab a reference to the
143 	 * snapshot vnode to prevent it from being removed while we are
144 	 * waiting for the buffer.
145 	 */
146 loop:
147 	flags = 0;
148 	if (IS_SNAPSHOT(ip))
149 		flags = GB_LOCK_NOWAIT;
150 	bn = fsbtodb(fs, ino_to_fsba(fs, ip->i_number));
151 	error = ffs_breadz(VFSTOUFS(vp->v_mount), ITODEVVP(ip), bn, bn,
152 	     (int) fs->fs_bsize, NULL, NULL, 0, NOCRED, flags, NULL, &bp);
153 	if (error != 0) {
154 		/*
155 		 * If EBUSY was returned without GB_LOCK_NOWAIT (which
156 		 * requests trylock for buffer lock), it is for some
157 		 * other reason and we should not handle it specially.
158 		 */
159 		if (error != EBUSY || (flags & GB_LOCK_NOWAIT) == 0)
160 			return (error);
161 
162 		/*
163 		 * Wait for our inode block to become available.
164 		 *
165 		 * Hold a reference to the vnode to protect against
166 		 * ffs_snapgone(). Since we hold a reference, it can only
167 		 * get reclaimed (VIRF_DOOMED flag) in a forcible downgrade
168 		 * or unmount. For an unmount, the entire filesystem will be
169 		 * gone, so we cannot attempt to touch anything associated
170 		 * with it while the vnode is unlocked; all we can do is
171 		 * pause briefly and try again. If when we relock the vnode
172 		 * we discover that it has been reclaimed, updating it is no
173 		 * longer necessary and we can just return an error.
174 		 */
175 		vref(vp);
176 		VOP_UNLOCK(vp);
177 		pause("ffsupd", 1);
178 		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
179 		vrele(vp);
180 		if (!IS_UFS(vp))
181 			return (ENOENT);
182 
183 		/*
184 		 * Recalculate flags, because the vnode was relocked and
185 		 * could no longer be a snapshot.
186 		 */
187 		goto loop;
188 	}
189 	if (DOINGSOFTDEP(vp))
190 		softdep_update_inodeblock(ip, bp, waitfor);
191 	else if (ip->i_effnlink != ip->i_nlink)
192 		panic("ffs_update: bad link cnt");
193 	if (I_IS_UFS1(ip)) {
194 		*((struct ufs1_dinode *)bp->b_data +
195 		    ino_to_fsbo(fs, ip->i_number)) = *ip->i_din1;
196 		/*
197 		 * XXX: FIX? The entropy here is desirable,
198 		 * but the harvesting may be expensive
199 		 */
200 		random_harvest_queue(&(ip->i_din1), sizeof(ip->i_din1), RANDOM_FS_ATIME);
201 	} else {
202 		ffs_update_dinode_ckhash(fs, ip->i_din2);
203 		*((struct ufs2_dinode *)bp->b_data +
204 		    ino_to_fsbo(fs, ip->i_number)) = *ip->i_din2;
205 		/*
206 		 * XXX: FIX? The entropy here is desirable,
207 		 * but the harvesting may be expensive
208 		 */
209 		random_harvest_queue(&(ip->i_din2), sizeof(ip->i_din2), RANDOM_FS_ATIME);
210 	}
211 	if (waitfor) {
212 		error = bwrite(bp);
213 		if (ffs_fsfail_cleanup(VFSTOUFS(vp->v_mount), error))
214 			error = 0;
215 	} else if (vm_page_count_severe() || buf_dirty_count_severe()) {
216 		bawrite(bp);
217 		error = 0;
218 	} else {
219 		if (bp->b_bufsize == fs->fs_bsize)
220 			bp->b_flags |= B_CLUSTEROK;
221 		bdwrite(bp);
222 		error = 0;
223 	}
224 	return (error);
225 }
226 
227 #define	SINGLE	0	/* index of single indirect block */
228 #define	DOUBLE	1	/* index of double indirect block */
229 #define	TRIPLE	2	/* index of triple indirect block */
230 /*
231  * Truncate the inode ip to at most length size, freeing the
232  * disk blocks.
233  */
234 int
235 ffs_truncate(struct vnode *vp,
236 	off_t length,
237 	int flags,
238 	struct ucred *cred)
239 {
240 	struct inode *ip;
241 	ufs2_daddr_t bn, lbn, lastblock, lastiblock[UFS_NIADDR];
242 	ufs2_daddr_t indir_lbn[UFS_NIADDR], oldblks[UFS_NDADDR + UFS_NIADDR];
243 	ufs2_daddr_t newblks[UFS_NDADDR + UFS_NIADDR];
244 	ufs2_daddr_t count, blocksreleased = 0, blkno;
245 	struct bufobj *bo __diagused;
246 	struct fs *fs;
247 	struct buf *bp;
248 	struct ufsmount *ump;
249 	int softdeptrunc, journaltrunc;
250 	int needextclean, extblocks;
251 	int offset, size, level, nblocks;
252 	int i, error, allerror, indiroff, waitforupdate;
253 	u_long key;
254 	off_t osize;
255 
256 	ip = VTOI(vp);
257 	ump = VFSTOUFS(vp->v_mount);
258 	fs = ump->um_fs;
259 	bo = &vp->v_bufobj;
260 
261 	ASSERT_VOP_LOCKED(vp, "ffs_truncate");
262 
263 	if (length < 0)
264 		return (EINVAL);
265 	if (length > fs->fs_maxfilesize)
266 		return (EFBIG);
267 #ifdef QUOTA
268 	error = getinoquota(ip);
269 	if (error)
270 		return (error);
271 #endif
272 	/*
273 	 * Historically clients did not have to specify which data
274 	 * they were truncating. So, if not specified, we assume
275 	 * traditional behavior, e.g., just the normal data.
276 	 */
277 	if ((flags & (IO_EXT | IO_NORMAL)) == 0)
278 		flags |= IO_NORMAL;
279 	if (!DOINGSOFTDEP(vp) && !DOINGASYNC(vp))
280 		flags |= IO_SYNC;
281 	waitforupdate = (flags & IO_SYNC) != 0 || !DOINGASYNC(vp);
282 	/*
283 	 * If we are truncating the extended-attributes, and cannot
284 	 * do it with soft updates, then do it slowly here. If we are
285 	 * truncating both the extended attributes and the file contents
286 	 * (e.g., the file is being unlinked), then pick it off with
287 	 * soft updates below.
288 	 */
289 	allerror = 0;
290 	needextclean = 0;
291 	softdeptrunc = 0;
292 	journaltrunc = DOINGSUJ(vp);
293 	journaltrunc = 0;	/* XXX temp patch until bug found */
294 	if (journaltrunc == 0 && DOINGSOFTDEP(vp) && length == 0)
295 		softdeptrunc = !softdep_slowdown(vp);
296 	extblocks = 0;
297 	if (fs->fs_magic == FS_UFS2_MAGIC && ip->i_din2->di_extsize > 0) {
298 		extblocks = btodb(fragroundup(fs, ip->i_din2->di_extsize));
299 	}
300 	if ((flags & IO_EXT) && extblocks > 0) {
301 		if (length != 0)
302 			panic("ffs_truncate: partial trunc of extdata");
303 		if (softdeptrunc || journaltrunc) {
304 			if ((flags & IO_NORMAL) == 0)
305 				goto extclean;
306 			needextclean = 1;
307 		} else {
308 			if ((error = ffs_syncvnode(vp, MNT_WAIT, 0)) != 0)
309 				return (error);
310 #ifdef QUOTA
311 			(void) chkdq(ip, -extblocks, NOCRED, FORCE);
312 #endif
313 			vinvalbuf(vp, V_ALT, 0, 0);
314 			vn_pages_remove(vp,
315 			    OFF_TO_IDX(lblktosize(fs, -extblocks)), 0);
316 			osize = ip->i_din2->di_extsize;
317 			ip->i_din2->di_blocks -= extblocks;
318 			ip->i_din2->di_extsize = 0;
319 			for (i = 0; i < UFS_NXADDR; i++) {
320 				oldblks[i] = ip->i_din2->di_extb[i];
321 				ip->i_din2->di_extb[i] = 0;
322 			}
323 			UFS_INODE_SET_FLAG(ip, IN_SIZEMOD | IN_CHANGE);
324 			if ((error = ffs_update(vp, waitforupdate)))
325 				return (error);
326 			for (i = 0; i < UFS_NXADDR; i++) {
327 				if (oldblks[i] == 0)
328 					continue;
329 				ffs_blkfree(ump, fs, ITODEVVP(ip), oldblks[i],
330 				    sblksize(fs, osize, i), ip->i_number,
331 				    vp->v_type, NULL, SINGLETON_KEY);
332 			}
333 		}
334 	}
335 	if ((flags & IO_NORMAL) == 0)
336 		return (0);
337 	if (vp->v_type == VLNK && ip->i_size < ump->um_maxsymlinklen) {
338 #ifdef INVARIANTS
339 		if (length != 0)
340 			panic("ffs_truncate: partial truncate of symlink");
341 #endif
342 		bzero(DIP(ip, i_shortlink), (u_int)ip->i_size);
343 		ip->i_size = 0;
344 		DIP_SET(ip, i_size, 0);
345 		UFS_INODE_SET_FLAG(ip, IN_SIZEMOD | IN_CHANGE | IN_UPDATE);
346 		if (needextclean)
347 			goto extclean;
348 		return (ffs_update(vp, waitforupdate));
349 	}
350 	if (ip->i_size == length) {
351 		UFS_INODE_SET_FLAG(ip, IN_CHANGE | IN_UPDATE);
352 		if (needextclean)
353 			goto extclean;
354 		return (ffs_update(vp, 0));
355 	}
356 	if (fs->fs_ronly)
357 		panic("ffs_truncate: read-only filesystem");
358 	if (IS_SNAPSHOT(ip))
359 		ffs_snapremove(vp);
360 	cluster_init_vn(&ip->i_clusterw);
361 	osize = ip->i_size;
362 	/*
363 	 * Lengthen the size of the file. We must ensure that the
364 	 * last byte of the file is allocated. Since the smallest
365 	 * value of osize is 0, length will be at least 1.
366 	 */
367 	if (osize < length) {
368 		vnode_pager_setsize(vp, length);
369 		flags |= BA_CLRBUF;
370 		error = UFS_BALLOC(vp, length - 1, 1, cred, flags, &bp);
371 		if (error) {
372 			vnode_pager_setsize(vp, osize);
373 			return (error);
374 		}
375 		ip->i_size = length;
376 		DIP_SET(ip, i_size, length);
377 		if (bp->b_bufsize == fs->fs_bsize)
378 			bp->b_flags |= B_CLUSTEROK;
379 		ffs_inode_bwrite(vp, bp, flags);
380 		UFS_INODE_SET_FLAG(ip, IN_SIZEMOD | IN_CHANGE | IN_UPDATE);
381 		return (ffs_update(vp, waitforupdate));
382 	}
383 	/*
384 	 * Lookup block number for a given offset. Zero length files
385 	 * have no blocks, so return a blkno of -1.
386 	 */
387 	lbn = lblkno(fs, length - 1);
388 	if (length == 0) {
389 		blkno = -1;
390 	} else if (lbn < UFS_NDADDR) {
391 		blkno = DIP(ip, i_db[lbn]);
392 	} else {
393 		error = UFS_BALLOC(vp, lblktosize(fs, (off_t)lbn), fs->fs_bsize,
394 		    cred, BA_METAONLY, &bp);
395 		if (error)
396 			return (error);
397 		indiroff = (lbn - UFS_NDADDR) % NINDIR(fs);
398 		if (I_IS_UFS1(ip))
399 			blkno = ((ufs1_daddr_t *)(bp->b_data))[indiroff];
400 		else
401 			blkno = ((ufs2_daddr_t *)(bp->b_data))[indiroff];
402 		/*
403 		 * If the block number is non-zero, then the indirect block
404 		 * must have been previously allocated and need not be written.
405 		 * If the block number is zero, then we may have allocated
406 		 * the indirect block and hence need to write it out.
407 		 */
408 		if (blkno != 0)
409 			brelse(bp);
410 		else if (flags & IO_SYNC)
411 			bwrite(bp);
412 		else
413 			bdwrite(bp);
414 	}
415 	/*
416 	 * If the block number at the new end of the file is zero,
417 	 * then we must allocate it to ensure that the last block of
418 	 * the file is allocated. Soft updates does not handle this
419 	 * case, so here we have to clean up the soft updates data
420 	 * structures describing the allocation past the truncation
421 	 * point. Finding and deallocating those structures is a lot of
422 	 * work. Since partial truncation with a hole at the end occurs
423 	 * rarely, we solve the problem by syncing the file so that it
424 	 * will have no soft updates data structures left.
425 	 */
426 	if (blkno == 0 && (error = ffs_syncvnode(vp, MNT_WAIT, 0)) != 0)
427 		return (error);
428 	if (blkno != 0 && DOINGSOFTDEP(vp)) {
429 		if (softdeptrunc == 0 && journaltrunc == 0) {
430 			/*
431 			 * If soft updates cannot handle this truncation,
432 			 * clean up soft dependency data structures and
433 			 * fall through to the synchronous truncation.
434 			 */
435 			if ((error = ffs_syncvnode(vp, MNT_WAIT, 0)) != 0)
436 				return (error);
437 		} else {
438 			flags = IO_NORMAL | (needextclean ? IO_EXT: 0);
439 			if (journaltrunc)
440 				softdep_journal_freeblocks(ip, cred, length,
441 				    flags);
442 			else
443 				softdep_setup_freeblocks(ip, length, flags);
444 			ASSERT_VOP_LOCKED(vp, "ffs_truncate1");
445 			if (journaltrunc == 0) {
446 				UFS_INODE_SET_FLAG(ip, IN_CHANGE | IN_UPDATE);
447 				error = ffs_update(vp, 0);
448 			}
449 			return (error);
450 		}
451 	}
452 	/*
453 	 * Shorten the size of the file. If the last block of the
454 	 * shortened file is unallocated, we must allocate it.
455 	 * Additionally, if the file is not being truncated to a
456 	 * block boundary, the contents of the partial block
457 	 * following the end of the file must be zero'ed in
458 	 * case it ever becomes accessible again because of
459 	 * subsequent file growth. Directories however are not
460 	 * zero'ed as they should grow back initialized to empty.
461 	 */
462 	offset = blkoff(fs, length);
463 	if (blkno != 0 && offset == 0) {
464 		ip->i_size = length;
465 		DIP_SET(ip, i_size, length);
466 		UFS_INODE_SET_FLAG(ip, IN_SIZEMOD | IN_CHANGE | IN_UPDATE);
467 #ifdef UFS_DIRHASH
468 		if (vp->v_type == VDIR && ip->i_dirhash != NULL)
469 			ufsdirhash_dirtrunc(ip, length);
470 #endif
471 	} else {
472 		lbn = lblkno(fs, length);
473 		flags |= BA_CLRBUF;
474 		error = UFS_BALLOC(vp, length - 1, 1, cred, flags, &bp);
475 		if (error)
476 			return (error);
477 		ffs_inode_bwrite(vp, bp, flags);
478 
479 		/*
480 		 * When we are doing soft updates and the UFS_BALLOC
481 		 * above fills in a direct block hole with a full sized
482 		 * block that will be truncated down to a fragment below,
483 		 * we must flush out the block dependency with an FSYNC
484 		 * so that we do not get a soft updates inconsistency
485 		 * when we create the fragment below.
486 		 */
487 		if (DOINGSOFTDEP(vp) && lbn < UFS_NDADDR &&
488 		    fragroundup(fs, blkoff(fs, length)) < fs->fs_bsize &&
489 		    (error = ffs_syncvnode(vp, MNT_WAIT, 0)) != 0)
490 			return (error);
491 
492 		error = UFS_BALLOC(vp, length - 1, 1, cred, flags, &bp);
493 		if (error)
494 			return (error);
495 		ip->i_size = length;
496 		DIP_SET(ip, i_size, length);
497 #ifdef UFS_DIRHASH
498 		if (vp->v_type == VDIR && ip->i_dirhash != NULL)
499 			ufsdirhash_dirtrunc(ip, length);
500 #endif
501 		size = blksize(fs, ip, lbn);
502 		if (vp->v_type != VDIR && offset != 0)
503 			bzero((char *)bp->b_data + offset,
504 			    (u_int)(size - offset));
505 		/* Kirk's code has reallocbuf(bp, size, 1) here */
506 		allocbuf(bp, size);
507 		if (bp->b_bufsize == fs->fs_bsize)
508 			bp->b_flags |= B_CLUSTEROK;
509 		ffs_inode_bwrite(vp, bp, flags);
510 		UFS_INODE_SET_FLAG(ip, IN_SIZEMOD | IN_CHANGE | IN_UPDATE);
511 	}
512 	/*
513 	 * Calculate index into inode's block list of
514 	 * last direct and indirect blocks (if any)
515 	 * which we want to keep.  Lastblock is -1 when
516 	 * the file is truncated to 0.
517 	 */
518 	lastblock = lblkno(fs, length + fs->fs_bsize - 1) - 1;
519 	lastiblock[SINGLE] = lastblock - UFS_NDADDR;
520 	lastiblock[DOUBLE] = lastiblock[SINGLE] - NINDIR(fs);
521 	lastiblock[TRIPLE] = lastiblock[DOUBLE] - NINDIR(fs) * NINDIR(fs);
522 	nblocks = btodb(fs->fs_bsize);
523 	/*
524 	 * Update file and block pointers on disk before we start freeing
525 	 * blocks.  If we crash before free'ing blocks below, the blocks
526 	 * will be returned to the free list.  lastiblock values are also
527 	 * normalized to -1 for calls to ffs_indirtrunc below.
528 	 */
529 	for (level = TRIPLE; level >= SINGLE; level--) {
530 		oldblks[UFS_NDADDR + level] = DIP(ip, i_ib[level]);
531 		if (lastiblock[level] < 0) {
532 			DIP_SET(ip, i_ib[level], 0);
533 			lastiblock[level] = -1;
534 		}
535 	}
536 	for (i = 0; i < UFS_NDADDR; i++) {
537 		oldblks[i] = DIP(ip, i_db[i]);
538 		if (i > lastblock)
539 			DIP_SET(ip, i_db[i], 0);
540 	}
541 	UFS_INODE_SET_FLAG(ip, IN_CHANGE | IN_UPDATE);
542 	allerror = ffs_update(vp, waitforupdate);
543 
544 	/*
545 	 * Having written the new inode to disk, save its new configuration
546 	 * and put back the old block pointers long enough to process them.
547 	 * Note that we save the new block configuration so we can check it
548 	 * when we are done.
549 	 */
550 	for (i = 0; i < UFS_NDADDR; i++) {
551 		newblks[i] = DIP(ip, i_db[i]);
552 		DIP_SET(ip, i_db[i], oldblks[i]);
553 	}
554 	for (i = 0; i < UFS_NIADDR; i++) {
555 		newblks[UFS_NDADDR + i] = DIP(ip, i_ib[i]);
556 		DIP_SET(ip, i_ib[i], oldblks[UFS_NDADDR + i]);
557 	}
558 	ip->i_size = osize;
559 	DIP_SET(ip, i_size, osize);
560 	UFS_INODE_SET_FLAG(ip, IN_SIZEMOD | IN_CHANGE | IN_UPDATE);
561 
562 	error = vtruncbuf(vp, length, fs->fs_bsize);
563 	if (error && (allerror == 0))
564 		allerror = error;
565 
566 	/*
567 	 * Indirect blocks first.
568 	 */
569 	indir_lbn[SINGLE] = -UFS_NDADDR;
570 	indir_lbn[DOUBLE] = indir_lbn[SINGLE] - NINDIR(fs) - 1;
571 	indir_lbn[TRIPLE] = indir_lbn[DOUBLE] - NINDIR(fs) * NINDIR(fs) - 1;
572 	for (level = TRIPLE; level >= SINGLE; level--) {
573 		bn = DIP(ip, i_ib[level]);
574 		if (bn != 0) {
575 			error = ffs_indirtrunc(ip, indir_lbn[level],
576 			    fsbtodb(fs, bn), lastiblock[level], level, &count);
577 			if (error)
578 				allerror = error;
579 			blocksreleased += count;
580 			if (lastiblock[level] < 0) {
581 				DIP_SET(ip, i_ib[level], 0);
582 				ffs_blkfree(ump, fs, ump->um_devvp, bn,
583 				    fs->fs_bsize, ip->i_number,
584 				    vp->v_type, NULL, SINGLETON_KEY);
585 				blocksreleased += nblocks;
586 			}
587 		}
588 		if (lastiblock[level] >= 0)
589 			goto done;
590 	}
591 
592 	/*
593 	 * All whole direct blocks or frags.
594 	 */
595 	key = ffs_blkrelease_start(ump, ump->um_devvp, ip->i_number);
596 	for (i = UFS_NDADDR - 1; i > lastblock; i--) {
597 		long bsize;
598 
599 		bn = DIP(ip, i_db[i]);
600 		if (bn == 0)
601 			continue;
602 		DIP_SET(ip, i_db[i], 0);
603 		bsize = blksize(fs, ip, i);
604 		ffs_blkfree(ump, fs, ump->um_devvp, bn, bsize, ip->i_number,
605 		    vp->v_type, NULL, key);
606 		blocksreleased += btodb(bsize);
607 	}
608 	ffs_blkrelease_finish(ump, key);
609 	if (lastblock < 0)
610 		goto done;
611 
612 	/*
613 	 * Finally, look for a change in size of the
614 	 * last direct block; release any frags.
615 	 */
616 	bn = DIP(ip, i_db[lastblock]);
617 	if (bn != 0) {
618 		long oldspace, newspace;
619 
620 		/*
621 		 * Calculate amount of space we're giving
622 		 * back as old block size minus new block size.
623 		 */
624 		oldspace = blksize(fs, ip, lastblock);
625 		ip->i_size = length;
626 		DIP_SET(ip, i_size, length);
627 		UFS_INODE_SET_FLAG(ip, IN_SIZEMOD | IN_CHANGE | IN_UPDATE);
628 		newspace = blksize(fs, ip, lastblock);
629 		if (newspace == 0)
630 			panic("ffs_truncate: newspace");
631 		if (oldspace - newspace > 0) {
632 			/*
633 			 * Block number of space to be free'd is
634 			 * the old block # plus the number of frags
635 			 * required for the storage we're keeping.
636 			 */
637 			bn += numfrags(fs, newspace);
638 			ffs_blkfree(ump, fs, ump->um_devvp, bn,
639 			   oldspace - newspace, ip->i_number, vp->v_type,
640 			   NULL, SINGLETON_KEY);
641 			blocksreleased += btodb(oldspace - newspace);
642 		}
643 	}
644 done:
645 #ifdef INVARIANTS
646 	for (level = SINGLE; level <= TRIPLE; level++)
647 		if (newblks[UFS_NDADDR + level] != DIP(ip, i_ib[level]))
648 			panic("ffs_truncate1: level %d newblks %jd != i_ib %jd",
649 			    level, (intmax_t)newblks[UFS_NDADDR + level],
650 			    (intmax_t)DIP(ip, i_ib[level]));
651 	for (i = 0; i < UFS_NDADDR; i++)
652 		if (newblks[i] != DIP(ip, i_db[i]))
653 			panic("ffs_truncate2: blkno %d newblks %jd != i_db %jd",
654 			    i, (intmax_t)newblks[UFS_NDADDR + level],
655 			    (intmax_t)DIP(ip, i_ib[level]));
656 	BO_LOCK(bo);
657 	if (length == 0 &&
658 	    (fs->fs_magic != FS_UFS2_MAGIC || ip->i_din2->di_extsize == 0) &&
659 	    (bo->bo_dirty.bv_cnt > 0 || bo->bo_clean.bv_cnt > 0))
660 		panic("ffs_truncate3: vp = %p, buffers: dirty = %d, clean = %d",
661 			vp, bo->bo_dirty.bv_cnt, bo->bo_clean.bv_cnt);
662 	BO_UNLOCK(bo);
663 #endif /* INVARIANTS */
664 	/*
665 	 * Put back the real size.
666 	 */
667 	ip->i_size = length;
668 	DIP_SET(ip, i_size, length);
669 	if (DIP(ip, i_blocks) >= blocksreleased)
670 		DIP_SET(ip, i_blocks, DIP(ip, i_blocks) - blocksreleased);
671 	else	/* sanity */
672 		DIP_SET(ip, i_blocks, 0);
673 	UFS_INODE_SET_FLAG(ip, IN_SIZEMOD | IN_CHANGE);
674 #ifdef QUOTA
675 	(void) chkdq(ip, -blocksreleased, NOCRED, FORCE);
676 #endif
677 	return (allerror);
678 
679 extclean:
680 	if (journaltrunc)
681 		softdep_journal_freeblocks(ip, cred, length, IO_EXT);
682 	else
683 		softdep_setup_freeblocks(ip, length, IO_EXT);
684 	return (ffs_update(vp, waitforupdate));
685 }
686 
687 /*
688  * Release blocks associated with the inode ip and stored in the indirect
689  * block bn.  Blocks are free'd in LIFO order up to (but not including)
690  * lastbn.  If level is greater than SINGLE, the block is an indirect block
691  * and recursive calls to indirtrunc must be used to cleanse other indirect
692  * blocks.
693  */
694 static int
695 ffs_indirtrunc(struct inode *ip,
696 	ufs2_daddr_t lbn,
697 	ufs2_daddr_t dbn,
698 	ufs2_daddr_t lastbn,
699 	int level,
700 	ufs2_daddr_t *countp)
701 {
702 	struct buf *bp;
703 	struct fs *fs;
704 	struct ufsmount *ump;
705 	struct vnode *vp;
706 	caddr_t copy = NULL;
707 	u_long key;
708 	int i, nblocks, error = 0, allerror = 0;
709 	ufs2_daddr_t nb, nlbn, last;
710 	ufs2_daddr_t blkcount, factor, blocksreleased = 0;
711 	ufs1_daddr_t *bap1 = NULL;
712 	ufs2_daddr_t *bap2 = NULL;
713 #define BAP(ip, i) (I_IS_UFS1(ip) ? bap1[i] : bap2[i])
714 
715 	fs = ITOFS(ip);
716 	ump = ITOUMP(ip);
717 
718 	/*
719 	 * Calculate index in current block of last
720 	 * block to be kept.  -1 indicates the entire
721 	 * block so we need not calculate the index.
722 	 */
723 	factor = lbn_offset(fs, level);
724 	last = lastbn;
725 	if (lastbn > 0)
726 		last /= factor;
727 	nblocks = btodb(fs->fs_bsize);
728 	/*
729 	 * Get buffer of block pointers, zero those entries corresponding
730 	 * to blocks to be free'd, and update on disk copy first.  Since
731 	 * double(triple) indirect before single(double) indirect, calls
732 	 * to VOP_BMAP() on these blocks will fail.  However, we already
733 	 * have the on-disk address, so we just pass it to bread() instead
734 	 * of having bread() attempt to calculate it using VOP_BMAP().
735 	 */
736 	vp = ITOV(ip);
737 	error = ffs_breadz(ump, vp, lbn, dbn, (int)fs->fs_bsize, NULL, NULL, 0,
738 	    NOCRED, 0, NULL, &bp);
739 	if (error) {
740 		*countp = 0;
741 		return (error);
742 	}
743 
744 	if (I_IS_UFS1(ip))
745 		bap1 = (ufs1_daddr_t *)bp->b_data;
746 	else
747 		bap2 = (ufs2_daddr_t *)bp->b_data;
748 	if (lastbn != -1) {
749 		copy = malloc(fs->fs_bsize, M_TEMP, M_WAITOK);
750 		bcopy((caddr_t)bp->b_data, copy, (u_int)fs->fs_bsize);
751 		for (i = last + 1; i < NINDIR(fs); i++)
752 			if (I_IS_UFS1(ip))
753 				bap1[i] = 0;
754 			else
755 				bap2[i] = 0;
756 		if (DOINGASYNC(vp)) {
757 			bdwrite(bp);
758 		} else {
759 			error = bwrite(bp);
760 			if (error)
761 				allerror = error;
762 		}
763 		if (I_IS_UFS1(ip))
764 			bap1 = (ufs1_daddr_t *)copy;
765 		else
766 			bap2 = (ufs2_daddr_t *)copy;
767 	}
768 
769 	/*
770 	 * Recursively free totally unused blocks.
771 	 */
772 	key = ffs_blkrelease_start(ump, ITODEVVP(ip), ip->i_number);
773 	for (i = NINDIR(fs) - 1, nlbn = lbn + 1 - i * factor; i > last;
774 	    i--, nlbn += factor) {
775 		nb = BAP(ip, i);
776 		if (nb == 0)
777 			continue;
778 		if (level > SINGLE) {
779 			if ((error = ffs_indirtrunc(ip, nlbn, fsbtodb(fs, nb),
780 			    (ufs2_daddr_t)-1, level - 1, &blkcount)) != 0)
781 				allerror = error;
782 			blocksreleased += blkcount;
783 		}
784 		ffs_blkfree(ump, fs, ITODEVVP(ip), nb, fs->fs_bsize,
785 		    ip->i_number, vp->v_type, NULL, key);
786 		blocksreleased += nblocks;
787 	}
788 	ffs_blkrelease_finish(ump, key);
789 
790 	/*
791 	 * Recursively free last partial block.
792 	 */
793 	if (level > SINGLE && lastbn >= 0) {
794 		last = lastbn % factor;
795 		nb = BAP(ip, i);
796 		if (nb != 0) {
797 			error = ffs_indirtrunc(ip, nlbn, fsbtodb(fs, nb),
798 			    last, level - 1, &blkcount);
799 			if (error)
800 				allerror = error;
801 			blocksreleased += blkcount;
802 		}
803 	}
804 	if (copy != NULL) {
805 		free(copy, M_TEMP);
806 	} else {
807 		bp->b_flags |= B_INVAL | B_NOCACHE;
808 		brelse(bp);
809 	}
810 
811 	*countp = blocksreleased;
812 	return (allerror);
813 }
814 
815 int
816 ffs_rdonly(struct inode *ip)
817 {
818 
819 	return (ITOFS(ip)->fs_ronly != 0);
820 }
821