1 /* $NetBSD: ulfs_bmap.c,v 1.7 2015/09/01 06:08:37 dholland Exp $ */
2 /* from NetBSD: ufs_bmap.c,v 1.50 2013/01/22 09:39:18 dholland Exp */
3
4 /*
5 * Copyright (c) 1989, 1991, 1993
6 * The Regents of the University of California. All rights reserved.
7 * (c) UNIX System Laboratories, Inc.
8 * All or some portions of this file are derived from material licensed
9 * to the University of California by American Telephone and Telegraph
10 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
11 * the permission of UNIX System Laboratories, Inc.
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 * 1. Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 * 2. Redistributions in binary form must reproduce the above copyright
19 * notice, this list of conditions and the following disclaimer in the
20 * documentation and/or other materials provided with the distribution.
21 * 3. Neither the name of the University nor the names of its contributors
22 * may be used to endorse or promote products derived from this software
23 * without specific prior written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 * SUCH DAMAGE.
36 *
37 * @(#)ufs_bmap.c 8.8 (Berkeley) 8/11/95
38 */
39
40 #include <sys/cdefs.h>
41 __KERNEL_RCSID(0, "$NetBSD: ulfs_bmap.c,v 1.7 2015/09/01 06:08:37 dholland Exp $");
42
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/stat.h>
46 #include <sys/buf.h>
47 #include <sys/proc.h>
48 #include <sys/vnode.h>
49 #include <sys/mount.h>
50 #include <sys/resourcevar.h>
51 #include <sys/trace.h>
52 #include <sys/fstrans.h>
53
54 #include <miscfs/specfs/specdev.h>
55
56 #include <ufs/lfs/ulfs_inode.h>
57 #include <ufs/lfs/ulfsmount.h>
58 #include <ufs/lfs/ulfs_extern.h>
59 #include <ufs/lfs/ulfs_bswap.h>
60
61 static bool
ulfs_issequential(const struct lfs * fs,daddr_t daddr0,daddr_t daddr1)62 ulfs_issequential(const struct lfs *fs, daddr_t daddr0, daddr_t daddr1)
63 {
64
65 /* for ulfs, blocks in a hole is not 'contiguous'. */
66 if (daddr0 == 0)
67 return false;
68
69 return (daddr0 + fs->um_seqinc == daddr1);
70 }
71
72 /*
73 * This is used for block pointers in inodes and elsewhere, which can
74 * contain the magic value UNWRITTEN, which is -2. This is mishandled
75 * by u32 -> u64 promotion unless special-cased.
76 *
77 * XXX this should be rolled into better inode accessors and go away.
78 */
79 static inline uint64_t
ulfs_fix_unwritten(uint32_t val)80 ulfs_fix_unwritten(uint32_t val)
81 {
82 if (val == (uint32_t)UNWRITTEN) {
83 return (uint64_t)(int64_t)UNWRITTEN;
84 } else {
85 return val;
86 }
87 }
88
89
90 /*
91 * Bmap converts the logical block number of a file to its physical block
92 * number on the disk. The conversion is done by using the logical block
93 * number to index into the array of block pointers described by the dinode.
94 */
95 int
ulfs_bmap(void * v)96 ulfs_bmap(void *v)
97 {
98 struct vop_bmap_args /* {
99 struct vnode *a_vp;
100 daddr_t a_bn;
101 struct vnode **a_vpp;
102 daddr_t *a_bnp;
103 int *a_runp;
104 } */ *ap = v;
105 int error;
106
107 /*
108 * Check for underlying vnode requests and ensure that logical
109 * to physical mapping is requested.
110 */
111 if (ap->a_vpp != NULL)
112 *ap->a_vpp = VTOI(ap->a_vp)->i_devvp;
113 if (ap->a_bnp == NULL)
114 return (0);
115
116 fstrans_start(ap->a_vp->v_mount, FSTRANS_SHARED);
117 error = ulfs_bmaparray(ap->a_vp, ap->a_bn, ap->a_bnp, NULL, NULL,
118 ap->a_runp, ulfs_issequential);
119 fstrans_done(ap->a_vp->v_mount);
120 return error;
121 }
122
123 /*
124 * Indirect blocks are now on the vnode for the file. They are given negative
125 * logical block numbers. Indirect blocks are addressed by the negative
126 * address of the first data block to which they point. Double indirect blocks
127 * are addressed by one less than the address of the first indirect block to
128 * which they point. Triple indirect blocks are addressed by one less than
129 * the address of the first double indirect block to which they point.
130 *
131 * ulfs_bmaparray does the bmap conversion, and if requested returns the
132 * array of logical blocks which must be traversed to get to a block.
133 * Each entry contains the offset into that block that gets you to the
134 * next block and the disk address of the block (if it is assigned).
135 */
136
137 int
ulfs_bmaparray(struct vnode * vp,daddr_t bn,daddr_t * bnp,struct indir * ap,int * nump,int * runp,ulfs_issequential_callback_t is_sequential)138 ulfs_bmaparray(struct vnode *vp, daddr_t bn, daddr_t *bnp, struct indir *ap,
139 int *nump, int *runp, ulfs_issequential_callback_t is_sequential)
140 {
141 struct inode *ip;
142 struct buf *bp, *cbp;
143 struct ulfsmount *ump;
144 struct lfs *fs;
145 struct mount *mp;
146 struct indir a[ULFS_NIADDR + 1], *xap;
147 daddr_t daddr;
148 daddr_t metalbn;
149 int error, maxrun = 0, num;
150
151 ip = VTOI(vp);
152 mp = vp->v_mount;
153 ump = ip->i_ump;
154 fs = ip->i_lfs;
155 #ifdef DIAGNOSTIC
156 if ((ap != NULL && nump == NULL) || (ap == NULL && nump != NULL))
157 panic("ulfs_bmaparray: invalid arguments");
158 #endif
159
160 if (runp) {
161 /*
162 * XXX
163 * If MAXBSIZE is the largest transfer the disks can handle,
164 * we probably want maxrun to be 1 block less so that we
165 * don't create a block larger than the device can handle.
166 */
167 *runp = 0;
168 maxrun = MAXPHYS / mp->mnt_stat.f_iosize - 1;
169 }
170
171 if (bn >= 0 && bn < ULFS_NDADDR) {
172 if (nump != NULL)
173 *nump = 0;
174 if (ump->um_fstype == ULFS1)
175 daddr = ulfs_fix_unwritten(ulfs_rw32(ip->i_din->u_32.di_db[bn],
176 ULFS_MPNEEDSWAP(fs)));
177 else
178 daddr = ulfs_rw64(ip->i_din->u_64.di_db[bn],
179 ULFS_MPNEEDSWAP(fs));
180 *bnp = blkptrtodb(fs, daddr);
181 /*
182 * Since this is FFS independent code, we are out of
183 * scope for the definitions of BLK_NOCOPY and
184 * BLK_SNAP, but we do know that they will fall in
185 * the range 1..um_seqinc, so we use that test and
186 * return a request for a zeroed out buffer if attempts
187 * are made to read a BLK_NOCOPY or BLK_SNAP block.
188 */
189 if ((ip->i_flags & (SF_SNAPSHOT | SF_SNAPINVAL)) == SF_SNAPSHOT
190 && daddr > 0 &&
191 daddr < fs->um_seqinc) {
192 *bnp = -1;
193 } else if (*bnp == 0) {
194 if ((ip->i_flags & (SF_SNAPSHOT | SF_SNAPINVAL))
195 == SF_SNAPSHOT) {
196 *bnp = blkptrtodb(fs, bn * fs->um_seqinc);
197 } else {
198 *bnp = -1;
199 }
200 } else if (runp) {
201 if (ump->um_fstype == ULFS1) {
202 for (++bn; bn < ULFS_NDADDR && *runp < maxrun &&
203 is_sequential(fs,
204 ulfs_fix_unwritten(ulfs_rw32(ip->i_din->u_32.di_db[bn - 1],
205 ULFS_MPNEEDSWAP(fs))),
206 ulfs_fix_unwritten(ulfs_rw32(ip->i_din->u_32.di_db[bn],
207 ULFS_MPNEEDSWAP(fs))));
208 ++bn, ++*runp);
209 } else {
210 for (++bn; bn < ULFS_NDADDR && *runp < maxrun &&
211 is_sequential(fs,
212 ulfs_rw64(ip->i_din->u_64.di_db[bn - 1],
213 ULFS_MPNEEDSWAP(fs)),
214 ulfs_rw64(ip->i_din->u_64.di_db[bn],
215 ULFS_MPNEEDSWAP(fs)));
216 ++bn, ++*runp);
217 }
218 }
219 return (0);
220 }
221
222 xap = ap == NULL ? a : ap;
223 if (!nump)
224 nump = #
225 if ((error = ulfs_getlbns(vp, bn, xap, nump)) != 0)
226 return (error);
227
228 num = *nump;
229
230 /* Get disk address out of indirect block array */
231 // XXX clean this up
232 if (ump->um_fstype == ULFS1)
233 daddr = ulfs_fix_unwritten(ulfs_rw32(ip->i_din->u_32.di_ib[xap->in_off],
234 ULFS_MPNEEDSWAP(fs)));
235 else
236 daddr = ulfs_rw64(ip->i_din->u_64.di_ib[xap->in_off],
237 ULFS_MPNEEDSWAP(fs));
238
239 for (bp = NULL, ++xap; --num; ++xap) {
240 /*
241 * Exit the loop if there is no disk address assigned yet and
242 * the indirect block isn't in the cache, or if we were
243 * looking for an indirect block and we've found it.
244 */
245
246 metalbn = xap->in_lbn;
247 if (metalbn == bn)
248 break;
249 if (daddr == 0) {
250 mutex_enter(&bufcache_lock);
251 cbp = incore(vp, metalbn);
252 mutex_exit(&bufcache_lock);
253 if (cbp == NULL)
254 break;
255 }
256
257 /*
258 * If we get here, we've either got the block in the cache
259 * or we have a disk address for it, go fetch it.
260 */
261 if (bp)
262 brelse(bp, 0);
263
264 xap->in_exists = 1;
265 bp = getblk(vp, metalbn, mp->mnt_stat.f_iosize, 0, 0);
266 if (bp == NULL) {
267
268 /*
269 * getblk() above returns NULL only iff we are
270 * pagedaemon. See the implementation of getblk
271 * for detail.
272 */
273
274 return (ENOMEM);
275 }
276 if (bp->b_oflags & (BO_DONE | BO_DELWRI)) {
277 trace(TR_BREADHIT, pack(vp, size), metalbn);
278 }
279 #ifdef DIAGNOSTIC
280 else if (!daddr)
281 panic("ulfs_bmaparray: indirect block not in cache");
282 #endif
283 else {
284 trace(TR_BREADMISS, pack(vp, size), metalbn);
285 bp->b_blkno = blkptrtodb(fs, daddr);
286 bp->b_flags |= B_READ;
287 BIO_SETPRIO(bp, BPRIO_TIMECRITICAL);
288 VOP_STRATEGY(vp, bp);
289 curlwp->l_ru.ru_inblock++; /* XXX */
290 if ((error = biowait(bp)) != 0) {
291 brelse(bp, 0);
292 return (error);
293 }
294 }
295 if (ump->um_fstype == ULFS1) {
296 daddr = ulfs_fix_unwritten(ulfs_rw32(((u_int32_t *)bp->b_data)[xap->in_off],
297 ULFS_MPNEEDSWAP(fs)));
298 if (num == 1 && daddr && runp) {
299 for (bn = xap->in_off + 1;
300 bn < MNINDIR(fs) && *runp < maxrun &&
301 is_sequential(fs,
302 ulfs_fix_unwritten(ulfs_rw32(((int32_t *)bp->b_data)[bn-1],
303 ULFS_MPNEEDSWAP(fs))),
304 ulfs_fix_unwritten(ulfs_rw32(((int32_t *)bp->b_data)[bn],
305 ULFS_MPNEEDSWAP(fs))));
306 ++bn, ++*runp);
307 }
308 } else {
309 daddr = ulfs_rw64(((u_int64_t *)bp->b_data)[xap->in_off],
310 ULFS_MPNEEDSWAP(fs));
311 if (num == 1 && daddr && runp) {
312 for (bn = xap->in_off + 1;
313 bn < MNINDIR(fs) && *runp < maxrun &&
314 is_sequential(fs,
315 ulfs_rw64(((int64_t *)bp->b_data)[bn-1],
316 ULFS_MPNEEDSWAP(fs)),
317 ulfs_rw64(((int64_t *)bp->b_data)[bn],
318 ULFS_MPNEEDSWAP(fs)));
319 ++bn, ++*runp);
320 }
321 }
322 }
323 if (bp)
324 brelse(bp, 0);
325
326 /*
327 * Since this is FFS independent code, we are out of scope for the
328 * definitions of BLK_NOCOPY and BLK_SNAP, but we do know that they
329 * will fall in the range 1..um_seqinc, so we use that test and
330 * return a request for a zeroed out buffer if attempts are made
331 * to read a BLK_NOCOPY or BLK_SNAP block.
332 */
333 if ((ip->i_flags & (SF_SNAPSHOT | SF_SNAPINVAL)) == SF_SNAPSHOT
334 && daddr > 0 && daddr < fs->um_seqinc) {
335 *bnp = -1;
336 return (0);
337 }
338 *bnp = blkptrtodb(fs, daddr);
339 if (*bnp == 0) {
340 if ((ip->i_flags & (SF_SNAPSHOT | SF_SNAPINVAL))
341 == SF_SNAPSHOT) {
342 *bnp = blkptrtodb(fs, bn * fs->um_seqinc);
343 } else {
344 *bnp = -1;
345 }
346 }
347 return (0);
348 }
349
350 /*
351 * Create an array of logical block number/offset pairs which represent the
352 * path of indirect blocks required to access a data block. The first "pair"
353 * contains the logical block number of the appropriate single, double or
354 * triple indirect block and the offset into the inode indirect block array.
355 * Note, the logical block number of the inode single/double/triple indirect
356 * block appears twice in the array, once with the offset into the i_ffs1_ib and
357 * once with the offset into the page itself.
358 */
359 int
ulfs_getlbns(struct vnode * vp,daddr_t bn,struct indir * ap,int * nump)360 ulfs_getlbns(struct vnode *vp, daddr_t bn, struct indir *ap, int *nump)
361 {
362 daddr_t metalbn, realbn;
363 struct ulfsmount *ump;
364 struct lfs *fs;
365 int64_t blockcnt;
366 int lbc;
367 int i, numlevels, off;
368
369 ump = VFSTOULFS(vp->v_mount);
370 fs = ump->um_lfs;
371 if (nump)
372 *nump = 0;
373 numlevels = 0;
374 realbn = bn;
375 if (bn < 0)
376 bn = -bn;
377 KASSERT(bn >= ULFS_NDADDR);
378
379 /*
380 * Determine the number of levels of indirection. After this loop
381 * is done, blockcnt indicates the number of data blocks possible
382 * at the given level of indirection, and ULFS_NIADDR - i is the number
383 * of levels of indirection needed to locate the requested block.
384 */
385
386 bn -= ULFS_NDADDR;
387 for (lbc = 0, i = ULFS_NIADDR;; i--, bn -= blockcnt) {
388 if (i == 0)
389 return (EFBIG);
390
391 lbc += fs->um_lognindir;
392 blockcnt = (int64_t)1 << lbc;
393
394 if (bn < blockcnt)
395 break;
396 }
397
398 /* Calculate the address of the first meta-block. */
399 metalbn = -((realbn >= 0 ? realbn : -realbn) - bn + ULFS_NIADDR - i);
400
401 /*
402 * At each iteration, off is the offset into the bap array which is
403 * an array of disk addresses at the current level of indirection.
404 * The logical block number and the offset in that block are stored
405 * into the argument array.
406 */
407 ap->in_lbn = metalbn;
408 ap->in_off = off = ULFS_NIADDR - i;
409 ap->in_exists = 0;
410 ap++;
411 for (++numlevels; i <= ULFS_NIADDR; i++) {
412 /* If searching for a meta-data block, quit when found. */
413 if (metalbn == realbn)
414 break;
415
416 lbc -= fs->um_lognindir;
417 off = (bn >> lbc) & (MNINDIR(fs) - 1);
418
419 ++numlevels;
420 ap->in_lbn = metalbn;
421 ap->in_off = off;
422 ap->in_exists = 0;
423 ++ap;
424
425 metalbn -= -1 + ((int64_t)off << lbc);
426 }
427 if (nump)
428 *nump = numlevels;
429 return (0);
430 }
431