xref: /freebsd/sys/ufs/ffs/ffs_inode.c (revision 3416500aef140042c64bc149cb1ec6620483bc44)
1 /*-
2  * Copyright (c) 1982, 1986, 1989, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  *	@(#)ffs_inode.c	8.13 (Berkeley) 4/21/95
30  */
31 
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
34 
35 #include "opt_quota.h"
36 
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/bio.h>
40 #include <sys/buf.h>
41 #include <sys/malloc.h>
42 #include <sys/mount.h>
43 #include <sys/proc.h>
44 #include <sys/racct.h>
45 #include <sys/random.h>
46 #include <sys/resourcevar.h>
47 #include <sys/rwlock.h>
48 #include <sys/stat.h>
49 #include <sys/vmmeter.h>
50 #include <sys/vnode.h>
51 
52 #include <vm/vm.h>
53 #include <vm/vm_extern.h>
54 #include <vm/vm_object.h>
55 
56 #include <ufs/ufs/extattr.h>
57 #include <ufs/ufs/quota.h>
58 #include <ufs/ufs/ufsmount.h>
59 #include <ufs/ufs/inode.h>
60 #include <ufs/ufs/ufs_extern.h>
61 
62 #include <ufs/ffs/fs.h>
63 #include <ufs/ffs/ffs_extern.h>
64 
65 static int ffs_indirtrunc(struct inode *, ufs2_daddr_t, ufs2_daddr_t,
66 	    ufs2_daddr_t, int, ufs2_daddr_t *);
67 
68 /*
69  * Update the access, modified, and inode change times as specified by the
70  * IN_ACCESS, IN_UPDATE, and IN_CHANGE flags respectively.  Write the inode
71  * to disk if the IN_MODIFIED flag is set (it may be set initially, or by
72  * the timestamp update).  The IN_LAZYMOD flag is set to force a write
73  * later if not now.  The IN_LAZYACCESS is set instead of IN_MODIFIED if the fs
74  * is currently being suspended (or is suspended) and vnode has been accessed.
75  * If we write now, then clear IN_MODIFIED, IN_LAZYACCESS and IN_LAZYMOD to
76  * reflect the presumably successful write, and if waitfor is set, then wait
77  * for the write to complete.
78  */
79 int
80 ffs_update(vp, waitfor)
81 	struct vnode *vp;
82 	int waitfor;
83 {
84 	struct fs *fs;
85 	struct buf *bp;
86 	struct inode *ip;
87 	int flags, error;
88 
89 	ASSERT_VOP_ELOCKED(vp, "ffs_update");
90 	ufs_itimes(vp);
91 	ip = VTOI(vp);
92 	if ((ip->i_flag & IN_MODIFIED) == 0 && waitfor == 0)
93 		return (0);
94 	ip->i_flag &= ~(IN_LAZYACCESS | IN_LAZYMOD | IN_MODIFIED);
95 	fs = ITOFS(ip);
96 	if (fs->fs_ronly && ITOUMP(ip)->um_fsckpid == 0)
97 		return (0);
98 	/*
99 	 * If we are updating a snapshot and another process is currently
100 	 * writing the buffer containing the inode for this snapshot then
101 	 * a deadlock can occur when it tries to check the snapshot to see
102 	 * if that block needs to be copied. Thus when updating a snapshot
103 	 * we check to see if the buffer is already locked, and if it is
104 	 * we drop the snapshot lock until the buffer has been written
105 	 * and is available to us. We have to grab a reference to the
106 	 * snapshot vnode to prevent it from being removed while we are
107 	 * waiting for the buffer.
108 	 */
109 	flags = 0;
110 	if (IS_SNAPSHOT(ip))
111 		flags = GB_LOCK_NOWAIT;
112 loop:
113 	error = breadn_flags(ITODEVVP(ip),
114 	     fsbtodb(fs, ino_to_fsba(fs, ip->i_number)),
115 	     (int) fs->fs_bsize, 0, 0, 0, NOCRED, flags, &bp);
116 	if (error != 0) {
117 		if (error != EBUSY)
118 			return (error);
119 		KASSERT((IS_SNAPSHOT(ip)), ("EBUSY from non-snapshot"));
120 		/*
121 		 * Wait for our inode block to become available.
122 		 *
123 		 * Hold a reference to the vnode to protect against
124 		 * ffs_snapgone(). Since we hold a reference, it can only
125 		 * get reclaimed (VI_DOOMED flag) in a forcible downgrade
126 		 * or unmount. For an unmount, the entire filesystem will be
127 		 * gone, so we cannot attempt to touch anything associated
128 		 * with it while the vnode is unlocked; all we can do is
129 		 * pause briefly and try again. If when we relock the vnode
130 		 * we discover that it has been reclaimed, updating it is no
131 		 * longer necessary and we can just return an error.
132 		 */
133 		vref(vp);
134 		VOP_UNLOCK(vp, 0);
135 		pause("ffsupd", 1);
136 		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
137 		vrele(vp);
138 		if ((vp->v_iflag & VI_DOOMED) != 0)
139 			return (ENOENT);
140 		goto loop;
141 	}
142 	if (DOINGSOFTDEP(vp))
143 		softdep_update_inodeblock(ip, bp, waitfor);
144 	else if (ip->i_effnlink != ip->i_nlink)
145 		panic("ffs_update: bad link cnt");
146 	if (I_IS_UFS1(ip)) {
147 		*((struct ufs1_dinode *)bp->b_data +
148 		    ino_to_fsbo(fs, ip->i_number)) = *ip->i_din1;
149 		/* XXX: FIX? The entropy here is desirable, but the harvesting may be expensive */
150 		random_harvest_queue(&(ip->i_din1), sizeof(ip->i_din1), 1, RANDOM_FS_ATIME);
151 	} else {
152 		*((struct ufs2_dinode *)bp->b_data +
153 		    ino_to_fsbo(fs, ip->i_number)) = *ip->i_din2;
154 		/* XXX: FIX? The entropy here is desirable, but the harvesting may be expensive */
155 		random_harvest_queue(&(ip->i_din2), sizeof(ip->i_din2), 1, RANDOM_FS_ATIME);
156 	}
157 	if (waitfor)
158 		error = bwrite(bp);
159 	else if (vm_page_count_severe() || buf_dirty_count_severe()) {
160 		bawrite(bp);
161 		error = 0;
162 	} else {
163 		if (bp->b_bufsize == fs->fs_bsize)
164 			bp->b_flags |= B_CLUSTEROK;
165 		bdwrite(bp);
166 		error = 0;
167 	}
168 	return (error);
169 }
170 
171 #define	SINGLE	0	/* index of single indirect block */
172 #define	DOUBLE	1	/* index of double indirect block */
173 #define	TRIPLE	2	/* index of triple indirect block */
174 /*
175  * Truncate the inode ip to at most length size, freeing the
176  * disk blocks.
177  */
178 int
179 ffs_truncate(vp, length, flags, cred)
180 	struct vnode *vp;
181 	off_t length;
182 	int flags;
183 	struct ucred *cred;
184 {
185 	struct inode *ip;
186 	ufs2_daddr_t bn, lbn, lastblock, lastiblock[UFS_NIADDR];
187 	ufs2_daddr_t indir_lbn[UFS_NIADDR], oldblks[UFS_NDADDR + UFS_NIADDR];
188 	ufs2_daddr_t newblks[UFS_NDADDR + UFS_NIADDR];
189 	ufs2_daddr_t count, blocksreleased = 0, datablocks, blkno;
190 	struct bufobj *bo;
191 	struct fs *fs;
192 	struct buf *bp;
193 	struct ufsmount *ump;
194 	int softdeptrunc, journaltrunc;
195 	int needextclean, extblocks;
196 	int offset, size, level, nblocks;
197 	int i, error, allerror, indiroff, waitforupdate;
198 	off_t osize;
199 
200 	ip = VTOI(vp);
201 	ump = VFSTOUFS(vp->v_mount);
202 	fs = ump->um_fs;
203 	bo = &vp->v_bufobj;
204 
205 	ASSERT_VOP_LOCKED(vp, "ffs_truncate");
206 
207 	if (length < 0)
208 		return (EINVAL);
209 	if (length > fs->fs_maxfilesize)
210 		return (EFBIG);
211 #ifdef QUOTA
212 	error = getinoquota(ip);
213 	if (error)
214 		return (error);
215 #endif
216 	/*
217 	 * Historically clients did not have to specify which data
218 	 * they were truncating. So, if not specified, we assume
219 	 * traditional behavior, e.g., just the normal data.
220 	 */
221 	if ((flags & (IO_EXT | IO_NORMAL)) == 0)
222 		flags |= IO_NORMAL;
223 	if (!DOINGSOFTDEP(vp) && !DOINGASYNC(vp))
224 		flags |= IO_SYNC;
225 	waitforupdate = (flags & IO_SYNC) != 0 || !DOINGASYNC(vp);
226 	/*
227 	 * If we are truncating the extended-attributes, and cannot
228 	 * do it with soft updates, then do it slowly here. If we are
229 	 * truncating both the extended attributes and the file contents
230 	 * (e.g., the file is being unlinked), then pick it off with
231 	 * soft updates below.
232 	 */
233 	allerror = 0;
234 	needextclean = 0;
235 	softdeptrunc = 0;
236 	journaltrunc = DOINGSUJ(vp);
237 	if (journaltrunc == 0 && DOINGSOFTDEP(vp) && length == 0)
238 		softdeptrunc = !softdep_slowdown(vp);
239 	extblocks = 0;
240 	datablocks = DIP(ip, i_blocks);
241 	if (fs->fs_magic == FS_UFS2_MAGIC && ip->i_din2->di_extsize > 0) {
242 		extblocks = btodb(fragroundup(fs, ip->i_din2->di_extsize));
243 		datablocks -= extblocks;
244 	}
245 	if ((flags & IO_EXT) && extblocks > 0) {
246 		if (length != 0)
247 			panic("ffs_truncate: partial trunc of extdata");
248 		if (softdeptrunc || journaltrunc) {
249 			if ((flags & IO_NORMAL) == 0)
250 				goto extclean;
251 			needextclean = 1;
252 		} else {
253 			if ((error = ffs_syncvnode(vp, MNT_WAIT, 0)) != 0)
254 				return (error);
255 #ifdef QUOTA
256 			(void) chkdq(ip, -extblocks, NOCRED, 0);
257 #endif
258 			vinvalbuf(vp, V_ALT, 0, 0);
259 			vn_pages_remove(vp,
260 			    OFF_TO_IDX(lblktosize(fs, -extblocks)), 0);
261 			osize = ip->i_din2->di_extsize;
262 			ip->i_din2->di_blocks -= extblocks;
263 			ip->i_din2->di_extsize = 0;
264 			for (i = 0; i < UFS_NXADDR; i++) {
265 				oldblks[i] = ip->i_din2->di_extb[i];
266 				ip->i_din2->di_extb[i] = 0;
267 			}
268 			ip->i_flag |= IN_CHANGE;
269 			if ((error = ffs_update(vp, waitforupdate)))
270 				return (error);
271 			for (i = 0; i < UFS_NXADDR; i++) {
272 				if (oldblks[i] == 0)
273 					continue;
274 				ffs_blkfree(ump, fs, ITODEVVP(ip), oldblks[i],
275 				    sblksize(fs, osize, i), ip->i_number,
276 				    vp->v_type, NULL);
277 			}
278 		}
279 	}
280 	if ((flags & IO_NORMAL) == 0)
281 		return (0);
282 	if (vp->v_type == VLNK &&
283 	    (ip->i_size < vp->v_mount->mnt_maxsymlinklen ||
284 	     datablocks == 0)) {
285 #ifdef INVARIANTS
286 		if (length != 0)
287 			panic("ffs_truncate: partial truncate of symlink");
288 #endif
289 		bzero(SHORTLINK(ip), (u_int)ip->i_size);
290 		ip->i_size = 0;
291 		DIP_SET(ip, i_size, 0);
292 		ip->i_flag |= IN_CHANGE | IN_UPDATE;
293 		if (needextclean)
294 			goto extclean;
295 		return (ffs_update(vp, waitforupdate));
296 	}
297 	if (ip->i_size == length) {
298 		ip->i_flag |= IN_CHANGE | IN_UPDATE;
299 		if (needextclean)
300 			goto extclean;
301 		return (ffs_update(vp, 0));
302 	}
303 	if (fs->fs_ronly)
304 		panic("ffs_truncate: read-only filesystem");
305 	if (IS_SNAPSHOT(ip))
306 		ffs_snapremove(vp);
307 	vp->v_lasta = vp->v_clen = vp->v_cstart = vp->v_lastw = 0;
308 	osize = ip->i_size;
309 	/*
310 	 * Lengthen the size of the file. We must ensure that the
311 	 * last byte of the file is allocated. Since the smallest
312 	 * value of osize is 0, length will be at least 1.
313 	 */
314 	if (osize < length) {
315 		vnode_pager_setsize(vp, length);
316 		flags |= BA_CLRBUF;
317 		error = UFS_BALLOC(vp, length - 1, 1, cred, flags, &bp);
318 		if (error) {
319 			vnode_pager_setsize(vp, osize);
320 			return (error);
321 		}
322 		ip->i_size = length;
323 		DIP_SET(ip, i_size, length);
324 		if (bp->b_bufsize == fs->fs_bsize)
325 			bp->b_flags |= B_CLUSTEROK;
326 		if (flags & IO_SYNC)
327 			bwrite(bp);
328 		else if (DOINGASYNC(vp))
329 			bdwrite(bp);
330 		else
331 			bawrite(bp);
332 		ip->i_flag |= IN_CHANGE | IN_UPDATE;
333 		return (ffs_update(vp, waitforupdate));
334 	}
335 	/*
336 	 * Lookup block number for a given offset. Zero length files
337 	 * have no blocks, so return a blkno of -1.
338 	 */
339 	lbn = lblkno(fs, length - 1);
340 	if (length == 0) {
341 		blkno = -1;
342 	} else if (lbn < UFS_NDADDR) {
343 		blkno = DIP(ip, i_db[lbn]);
344 	} else {
345 		error = UFS_BALLOC(vp, lblktosize(fs, (off_t)lbn), fs->fs_bsize,
346 		    cred, BA_METAONLY, &bp);
347 		if (error)
348 			return (error);
349 		indiroff = (lbn - UFS_NDADDR) % NINDIR(fs);
350 		if (I_IS_UFS1(ip))
351 			blkno = ((ufs1_daddr_t *)(bp->b_data))[indiroff];
352 		else
353 			blkno = ((ufs2_daddr_t *)(bp->b_data))[indiroff];
354 		/*
355 		 * If the block number is non-zero, then the indirect block
356 		 * must have been previously allocated and need not be written.
357 		 * If the block number is zero, then we may have allocated
358 		 * the indirect block and hence need to write it out.
359 		 */
360 		if (blkno != 0)
361 			brelse(bp);
362 		else if (flags & IO_SYNC)
363 			bwrite(bp);
364 		else
365 			bdwrite(bp);
366 	}
367 	/*
368 	 * If the block number at the new end of the file is zero,
369 	 * then we must allocate it to ensure that the last block of
370 	 * the file is allocated. Soft updates does not handle this
371 	 * case, so here we have to clean up the soft updates data
372 	 * structures describing the allocation past the truncation
373 	 * point. Finding and deallocating those structures is a lot of
374 	 * work. Since partial truncation with a hole at the end occurs
375 	 * rarely, we solve the problem by syncing the file so that it
376 	 * will have no soft updates data structures left.
377 	 */
378 	if (blkno == 0 && (error = ffs_syncvnode(vp, MNT_WAIT, 0)) != 0)
379 		return (error);
380 	if (blkno != 0 && DOINGSOFTDEP(vp)) {
381 		if (softdeptrunc == 0 && journaltrunc == 0) {
382 			/*
383 			 * If soft updates cannot handle this truncation,
384 			 * clean up soft dependency data structures and
385 			 * fall through to the synchronous truncation.
386 			 */
387 			if ((error = ffs_syncvnode(vp, MNT_WAIT, 0)) != 0)
388 				return (error);
389 		} else {
390 			flags = IO_NORMAL | (needextclean ? IO_EXT: 0);
391 			if (journaltrunc)
392 				softdep_journal_freeblocks(ip, cred, length,
393 				    flags);
394 			else
395 				softdep_setup_freeblocks(ip, length, flags);
396 			ASSERT_VOP_LOCKED(vp, "ffs_truncate1");
397 			if (journaltrunc == 0) {
398 				ip->i_flag |= IN_CHANGE | IN_UPDATE;
399 				error = ffs_update(vp, 0);
400 			}
401 			return (error);
402 		}
403 	}
404 	/*
405 	 * Shorten the size of the file. If the last block of the
406 	 * shortened file is unallocated, we must allocate it.
407 	 * Additionally, if the file is not being truncated to a
408 	 * block boundary, the contents of the partial block
409 	 * following the end of the file must be zero'ed in
410 	 * case it ever becomes accessible again because of
411 	 * subsequent file growth. Directories however are not
412 	 * zero'ed as they should grow back initialized to empty.
413 	 */
414 	offset = blkoff(fs, length);
415 	if (blkno != 0 && offset == 0) {
416 		ip->i_size = length;
417 		DIP_SET(ip, i_size, length);
418 	} else {
419 		lbn = lblkno(fs, length);
420 		flags |= BA_CLRBUF;
421 		error = UFS_BALLOC(vp, length - 1, 1, cred, flags, &bp);
422 		if (error)
423 			return (error);
424 		/*
425 		 * When we are doing soft updates and the UFS_BALLOC
426 		 * above fills in a direct block hole with a full sized
427 		 * block that will be truncated down to a fragment below,
428 		 * we must flush out the block dependency with an FSYNC
429 		 * so that we do not get a soft updates inconsistency
430 		 * when we create the fragment below.
431 		 */
432 		if (DOINGSOFTDEP(vp) && lbn < UFS_NDADDR &&
433 		    fragroundup(fs, blkoff(fs, length)) < fs->fs_bsize &&
434 		    (error = ffs_syncvnode(vp, MNT_WAIT, 0)) != 0)
435 			return (error);
436 		ip->i_size = length;
437 		DIP_SET(ip, i_size, length);
438 		size = blksize(fs, ip, lbn);
439 		if (vp->v_type != VDIR && offset != 0)
440 			bzero((char *)bp->b_data + offset,
441 			    (u_int)(size - offset));
442 		/* Kirk's code has reallocbuf(bp, size, 1) here */
443 		allocbuf(bp, size);
444 		if (bp->b_bufsize == fs->fs_bsize)
445 			bp->b_flags |= B_CLUSTEROK;
446 		if (flags & IO_SYNC)
447 			bwrite(bp);
448 		else if (DOINGASYNC(vp))
449 			bdwrite(bp);
450 		else
451 			bawrite(bp);
452 	}
453 	/*
454 	 * Calculate index into inode's block list of
455 	 * last direct and indirect blocks (if any)
456 	 * which we want to keep.  Lastblock is -1 when
457 	 * the file is truncated to 0.
458 	 */
459 	lastblock = lblkno(fs, length + fs->fs_bsize - 1) - 1;
460 	lastiblock[SINGLE] = lastblock - UFS_NDADDR;
461 	lastiblock[DOUBLE] = lastiblock[SINGLE] - NINDIR(fs);
462 	lastiblock[TRIPLE] = lastiblock[DOUBLE] - NINDIR(fs) * NINDIR(fs);
463 	nblocks = btodb(fs->fs_bsize);
464 	/*
465 	 * Update file and block pointers on disk before we start freeing
466 	 * blocks.  If we crash before free'ing blocks below, the blocks
467 	 * will be returned to the free list.  lastiblock values are also
468 	 * normalized to -1 for calls to ffs_indirtrunc below.
469 	 */
470 	for (level = TRIPLE; level >= SINGLE; level--) {
471 		oldblks[UFS_NDADDR + level] = DIP(ip, i_ib[level]);
472 		if (lastiblock[level] < 0) {
473 			DIP_SET(ip, i_ib[level], 0);
474 			lastiblock[level] = -1;
475 		}
476 	}
477 	for (i = 0; i < UFS_NDADDR; i++) {
478 		oldblks[i] = DIP(ip, i_db[i]);
479 		if (i > lastblock)
480 			DIP_SET(ip, i_db[i], 0);
481 	}
482 	ip->i_flag |= IN_CHANGE | IN_UPDATE;
483 	allerror = ffs_update(vp, waitforupdate);
484 
485 	/*
486 	 * Having written the new inode to disk, save its new configuration
487 	 * and put back the old block pointers long enough to process them.
488 	 * Note that we save the new block configuration so we can check it
489 	 * when we are done.
490 	 */
491 	for (i = 0; i < UFS_NDADDR; i++) {
492 		newblks[i] = DIP(ip, i_db[i]);
493 		DIP_SET(ip, i_db[i], oldblks[i]);
494 	}
495 	for (i = 0; i < UFS_NIADDR; i++) {
496 		newblks[UFS_NDADDR + i] = DIP(ip, i_ib[i]);
497 		DIP_SET(ip, i_ib[i], oldblks[UFS_NDADDR + i]);
498 	}
499 	ip->i_size = osize;
500 	DIP_SET(ip, i_size, osize);
501 
502 	error = vtruncbuf(vp, cred, length, fs->fs_bsize);
503 	if (error && (allerror == 0))
504 		allerror = error;
505 
506 	/*
507 	 * Indirect blocks first.
508 	 */
509 	indir_lbn[SINGLE] = -UFS_NDADDR;
510 	indir_lbn[DOUBLE] = indir_lbn[SINGLE] - NINDIR(fs) - 1;
511 	indir_lbn[TRIPLE] = indir_lbn[DOUBLE] - NINDIR(fs) * NINDIR(fs) - 1;
512 	for (level = TRIPLE; level >= SINGLE; level--) {
513 		bn = DIP(ip, i_ib[level]);
514 		if (bn != 0) {
515 			error = ffs_indirtrunc(ip, indir_lbn[level],
516 			    fsbtodb(fs, bn), lastiblock[level], level, &count);
517 			if (error)
518 				allerror = error;
519 			blocksreleased += count;
520 			if (lastiblock[level] < 0) {
521 				DIP_SET(ip, i_ib[level], 0);
522 				ffs_blkfree(ump, fs, ump->um_devvp, bn,
523 				    fs->fs_bsize, ip->i_number,
524 				    vp->v_type, NULL);
525 				blocksreleased += nblocks;
526 			}
527 		}
528 		if (lastiblock[level] >= 0)
529 			goto done;
530 	}
531 
532 	/*
533 	 * All whole direct blocks or frags.
534 	 */
535 	for (i = UFS_NDADDR - 1; i > lastblock; i--) {
536 		long bsize;
537 
538 		bn = DIP(ip, i_db[i]);
539 		if (bn == 0)
540 			continue;
541 		DIP_SET(ip, i_db[i], 0);
542 		bsize = blksize(fs, ip, i);
543 		ffs_blkfree(ump, fs, ump->um_devvp, bn, bsize, ip->i_number,
544 		    vp->v_type, NULL);
545 		blocksreleased += btodb(bsize);
546 	}
547 	if (lastblock < 0)
548 		goto done;
549 
550 	/*
551 	 * Finally, look for a change in size of the
552 	 * last direct block; release any frags.
553 	 */
554 	bn = DIP(ip, i_db[lastblock]);
555 	if (bn != 0) {
556 		long oldspace, newspace;
557 
558 		/*
559 		 * Calculate amount of space we're giving
560 		 * back as old block size minus new block size.
561 		 */
562 		oldspace = blksize(fs, ip, lastblock);
563 		ip->i_size = length;
564 		DIP_SET(ip, i_size, length);
565 		newspace = blksize(fs, ip, lastblock);
566 		if (newspace == 0)
567 			panic("ffs_truncate: newspace");
568 		if (oldspace - newspace > 0) {
569 			/*
570 			 * Block number of space to be free'd is
571 			 * the old block # plus the number of frags
572 			 * required for the storage we're keeping.
573 			 */
574 			bn += numfrags(fs, newspace);
575 			ffs_blkfree(ump, fs, ump->um_devvp, bn,
576 			   oldspace - newspace, ip->i_number, vp->v_type, NULL);
577 			blocksreleased += btodb(oldspace - newspace);
578 		}
579 	}
580 done:
581 #ifdef INVARIANTS
582 	for (level = SINGLE; level <= TRIPLE; level++)
583 		if (newblks[UFS_NDADDR + level] != DIP(ip, i_ib[level]))
584 			panic("ffs_truncate1");
585 	for (i = 0; i < UFS_NDADDR; i++)
586 		if (newblks[i] != DIP(ip, i_db[i]))
587 			panic("ffs_truncate2");
588 	BO_LOCK(bo);
589 	if (length == 0 &&
590 	    (fs->fs_magic != FS_UFS2_MAGIC || ip->i_din2->di_extsize == 0) &&
591 	    (bo->bo_dirty.bv_cnt > 0 || bo->bo_clean.bv_cnt > 0))
592 		panic("ffs_truncate3");
593 	BO_UNLOCK(bo);
594 #endif /* INVARIANTS */
595 	/*
596 	 * Put back the real size.
597 	 */
598 	ip->i_size = length;
599 	DIP_SET(ip, i_size, length);
600 	if (DIP(ip, i_blocks) >= blocksreleased)
601 		DIP_SET(ip, i_blocks, DIP(ip, i_blocks) - blocksreleased);
602 	else	/* sanity */
603 		DIP_SET(ip, i_blocks, 0);
604 	ip->i_flag |= IN_CHANGE;
605 #ifdef QUOTA
606 	(void) chkdq(ip, -blocksreleased, NOCRED, 0);
607 #endif
608 	return (allerror);
609 
610 extclean:
611 	if (journaltrunc)
612 		softdep_journal_freeblocks(ip, cred, length, IO_EXT);
613 	else
614 		softdep_setup_freeblocks(ip, length, IO_EXT);
615 	return (ffs_update(vp, waitforupdate));
616 }
617 
618 /*
619  * Release blocks associated with the inode ip and stored in the indirect
620  * block bn.  Blocks are free'd in LIFO order up to (but not including)
621  * lastbn.  If level is greater than SINGLE, the block is an indirect block
622  * and recursive calls to indirtrunc must be used to cleanse other indirect
623  * blocks.
624  */
625 static int
626 ffs_indirtrunc(ip, lbn, dbn, lastbn, level, countp)
627 	struct inode *ip;
628 	ufs2_daddr_t lbn, lastbn;
629 	ufs2_daddr_t dbn;
630 	int level;
631 	ufs2_daddr_t *countp;
632 {
633 	struct buf *bp;
634 	struct fs *fs;
635 	struct vnode *vp;
636 	caddr_t copy = NULL;
637 	int i, nblocks, error = 0, allerror = 0;
638 	ufs2_daddr_t nb, nlbn, last;
639 	ufs2_daddr_t blkcount, factor, blocksreleased = 0;
640 	ufs1_daddr_t *bap1 = NULL;
641 	ufs2_daddr_t *bap2 = NULL;
642 #define BAP(ip, i) (I_IS_UFS1(ip) ? bap1[i] : bap2[i])
643 
644 	fs = ITOFS(ip);
645 
646 	/*
647 	 * Calculate index in current block of last
648 	 * block to be kept.  -1 indicates the entire
649 	 * block so we need not calculate the index.
650 	 */
651 	factor = lbn_offset(fs, level);
652 	last = lastbn;
653 	if (lastbn > 0)
654 		last /= factor;
655 	nblocks = btodb(fs->fs_bsize);
656 	/*
657 	 * Get buffer of block pointers, zero those entries corresponding
658 	 * to blocks to be free'd, and update on disk copy first.  Since
659 	 * double(triple) indirect before single(double) indirect, calls
660 	 * to bmap on these blocks will fail.  However, we already have
661 	 * the on disk address, so we have to set the b_blkno field
662 	 * explicitly instead of letting bread do everything for us.
663 	 */
664 	vp = ITOV(ip);
665 	bp = getblk(vp, lbn, (int)fs->fs_bsize, 0, 0, 0);
666 	if ((bp->b_flags & B_CACHE) == 0) {
667 #ifdef RACCT
668 		if (racct_enable) {
669 			PROC_LOCK(curproc);
670 			racct_add_buf(curproc, bp, 0);
671 			PROC_UNLOCK(curproc);
672 		}
673 #endif /* RACCT */
674 		curthread->td_ru.ru_inblock++;	/* pay for read */
675 		bp->b_iocmd = BIO_READ;
676 		bp->b_flags &= ~B_INVAL;
677 		bp->b_ioflags &= ~BIO_ERROR;
678 		if (bp->b_bcount > bp->b_bufsize)
679 			panic("ffs_indirtrunc: bad buffer size");
680 		bp->b_blkno = dbn;
681 		vfs_busy_pages(bp, 0);
682 		bp->b_iooffset = dbtob(bp->b_blkno);
683 		bstrategy(bp);
684 		error = bufwait(bp);
685 	}
686 	if (error) {
687 		brelse(bp);
688 		*countp = 0;
689 		return (error);
690 	}
691 
692 	if (I_IS_UFS1(ip))
693 		bap1 = (ufs1_daddr_t *)bp->b_data;
694 	else
695 		bap2 = (ufs2_daddr_t *)bp->b_data;
696 	if (lastbn != -1) {
697 		copy = malloc(fs->fs_bsize, M_TEMP, M_WAITOK);
698 		bcopy((caddr_t)bp->b_data, copy, (u_int)fs->fs_bsize);
699 		for (i = last + 1; i < NINDIR(fs); i++)
700 			if (I_IS_UFS1(ip))
701 				bap1[i] = 0;
702 			else
703 				bap2[i] = 0;
704 		if (DOINGASYNC(vp)) {
705 			bdwrite(bp);
706 		} else {
707 			error = bwrite(bp);
708 			if (error)
709 				allerror = error;
710 		}
711 		if (I_IS_UFS1(ip))
712 			bap1 = (ufs1_daddr_t *)copy;
713 		else
714 			bap2 = (ufs2_daddr_t *)copy;
715 	}
716 
717 	/*
718 	 * Recursively free totally unused blocks.
719 	 */
720 	for (i = NINDIR(fs) - 1, nlbn = lbn + 1 - i * factor; i > last;
721 	    i--, nlbn += factor) {
722 		nb = BAP(ip, i);
723 		if (nb == 0)
724 			continue;
725 		if (level > SINGLE) {
726 			if ((error = ffs_indirtrunc(ip, nlbn, fsbtodb(fs, nb),
727 			    (ufs2_daddr_t)-1, level - 1, &blkcount)) != 0)
728 				allerror = error;
729 			blocksreleased += blkcount;
730 		}
731 		ffs_blkfree(ITOUMP(ip), fs, ITODEVVP(ip), nb, fs->fs_bsize,
732 		    ip->i_number, vp->v_type, NULL);
733 		blocksreleased += nblocks;
734 	}
735 
736 	/*
737 	 * Recursively free last partial block.
738 	 */
739 	if (level > SINGLE && lastbn >= 0) {
740 		last = lastbn % factor;
741 		nb = BAP(ip, i);
742 		if (nb != 0) {
743 			error = ffs_indirtrunc(ip, nlbn, fsbtodb(fs, nb),
744 			    last, level - 1, &blkcount);
745 			if (error)
746 				allerror = error;
747 			blocksreleased += blkcount;
748 		}
749 	}
750 	if (copy != NULL) {
751 		free(copy, M_TEMP);
752 	} else {
753 		bp->b_flags |= B_INVAL | B_NOCACHE;
754 		brelse(bp);
755 	}
756 
757 	*countp = blocksreleased;
758 	return (allerror);
759 }
760 
761 int
762 ffs_rdonly(struct inode *ip)
763 {
764 
765 	return (ITOFS(ip)->fs_ronly != 0);
766 }
767 
768