1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1989, 1991, 1993
5 * The Regents of the University of California. All rights reserved.
6 * (c) UNIX System Laboratories, Inc.
7 * All or some portions of this file are derived from material licensed
8 * to the University of California by American Telephone and Telegraph
9 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
10 * the permission of UNIX System Laboratories, Inc.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/bio.h>
40 #include <sys/buf.h>
41 #include <sys/endian.h>
42 #include <sys/proc.h>
43 #include <sys/vnode.h>
44 #include <sys/mount.h>
45 #include <sys/racct.h>
46 #include <sys/resourcevar.h>
47 #include <sys/stat.h>
48
49 #include <fs/ext2fs/fs.h>
50 #include <fs/ext2fs/inode.h>
51 #include <fs/ext2fs/ext2fs.h>
52 #include <fs/ext2fs/ext2_dinode.h>
53 #include <fs/ext2fs/ext2_extern.h>
54 #include <fs/ext2fs/ext2_mount.h>
55
56 /*
57 * Bmap converts the logical block number of a file to its physical block
58 * number on the disk. The conversion is done by using the logical block
59 * number to index into the array of block pointers described by the dinode.
60 */
61 int
ext2_bmap(struct vop_bmap_args * ap)62 ext2_bmap(struct vop_bmap_args *ap)
63 {
64 daddr_t blkno;
65 int error;
66
67 /*
68 * Check for underlying vnode requests and ensure that logical
69 * to physical mapping is requested.
70 */
71 if (ap->a_bop != NULL)
72 *ap->a_bop = &VTOI(ap->a_vp)->i_devvp->v_bufobj;
73 if (ap->a_bnp == NULL)
74 return (0);
75
76 if (VTOI(ap->a_vp)->i_flag & IN_E4EXTENTS)
77 error = ext4_bmapext(ap->a_vp, ap->a_bn, &blkno,
78 ap->a_runp, ap->a_runb);
79 else
80 error = ext2_bmaparray(ap->a_vp, ap->a_bn, &blkno,
81 ap->a_runp, ap->a_runb);
82 *ap->a_bnp = blkno;
83 return (error);
84 }
85
86 /*
87 * Convert the logical block number of a file to its physical block number
88 * on the disk within ext4 extents.
89 */
90 int
ext4_bmapext(struct vnode * vp,int32_t bn,int64_t * bnp,int * runp,int * runb)91 ext4_bmapext(struct vnode *vp, int32_t bn, int64_t *bnp, int *runp, int *runb)
92 {
93 struct inode *ip;
94 struct m_ext2fs *fs;
95 struct mount *mp;
96 struct ext2mount *ump;
97 struct ext4_extent_header *ehp;
98 struct ext4_extent *ep;
99 struct ext4_extent_path *path = NULL;
100 daddr_t lbn;
101 int error, depth, maxrun = 0, bsize;
102
103 ip = VTOI(vp);
104 fs = ip->i_e2fs;
105 mp = vp->v_mount;
106 ump = VFSTOEXT2(mp);
107 lbn = bn;
108 ehp = (struct ext4_extent_header *)ip->i_data;
109 depth = le16toh(ehp->eh_depth);
110 bsize = EXT2_BLOCK_SIZE(ump->um_e2fs);
111
112 *bnp = -1;
113 if (runp != NULL) {
114 maxrun = mp->mnt_iosize_max / bsize - 1;
115 *runp = 0;
116 }
117 if (runb != NULL)
118 *runb = 0;
119
120 error = ext4_ext_find_extent(ip, lbn, &path);
121 if (error)
122 return (error);
123
124 ep = path[depth].ep_ext;
125 if(ep) {
126 if (lbn < le32toh(ep->e_blk)) {
127 if (runp != NULL) {
128 *runp = min(maxrun, le32toh(ep->e_blk) - lbn - 1);
129 }
130 } else if (le32toh(ep->e_blk) <= lbn &&
131 lbn < le32toh(ep->e_blk) + le16toh(ep->e_len)) {
132 *bnp = fsbtodb(fs, lbn - le32toh(ep->e_blk) +
133 (le32toh(ep->e_start_lo) |
134 (daddr_t)le16toh(ep->e_start_hi) << 32));
135 if (runp != NULL) {
136 *runp = min(maxrun,
137 le16toh(ep->e_len) -
138 (lbn - le32toh(ep->e_blk)) - 1);
139 }
140 if (runb != NULL)
141 *runb = min(maxrun, lbn - le32toh(ep->e_blk));
142 } else {
143 if (runb != NULL)
144 *runb = min(maxrun, le32toh(ep->e_blk) + lbn -
145 le16toh(ep->e_len));
146 }
147 }
148
149 ext4_ext_path_free(path);
150
151 return (error);
152 }
153
154 static int
readindir(struct vnode * vp,e2fs_lbn_t lbn,e2fs_daddr_t daddr,struct buf ** bpp)155 readindir(struct vnode *vp, e2fs_lbn_t lbn, e2fs_daddr_t daddr, struct buf **bpp)
156 {
157 struct buf *bp;
158 struct mount *mp;
159 struct ext2mount *ump;
160 int error;
161
162 mp = vp->v_mount;
163 ump = VFSTOEXT2(mp);
164
165 bp = getblk(vp, lbn, mp->mnt_stat.f_iosize, 0, 0, 0);
166 if ((bp->b_flags & B_CACHE) == 0) {
167 KASSERT(daddr != 0,
168 ("readindir: indirect block not in cache"));
169
170 bp->b_blkno = blkptrtodb(ump, daddr);
171 bp->b_iocmd = BIO_READ;
172 bp->b_flags &= ~B_INVAL;
173 bp->b_ioflags &= ~BIO_ERROR;
174 vfs_busy_pages(bp, 0);
175 bp->b_iooffset = dbtob(bp->b_blkno);
176 bstrategy(bp);
177 #ifdef RACCT
178 if (racct_enable) {
179 PROC_LOCK(curproc);
180 racct_add_buf(curproc, bp, 0);
181 PROC_UNLOCK(curproc);
182 }
183 #endif
184 curthread->td_ru.ru_inblock++;
185 error = bufwait(bp);
186 if (error != 0) {
187 brelse(bp);
188 return (error);
189 }
190 }
191 *bpp = bp;
192 return (0);
193 }
194
195 /*
196 * Indirect blocks are now on the vnode for the file. They are given negative
197 * logical block numbers. Indirect blocks are addressed by the negative
198 * address of the first data block to which they point. Double indirect blocks
199 * are addressed by one less than the address of the first indirect block to
200 * which they point. Triple indirect blocks are addressed by one less than
201 * the address of the first double indirect block to which they point.
202 *
203 * ext2_bmaparray does the bmap conversion, and if requested returns the
204 * array of logical blocks which must be traversed to get to a block.
205 * Each entry contains the offset into that block that gets you to the
206 * next block and the disk address of the block (if it is assigned).
207 */
208
209 int
ext2_bmaparray(struct vnode * vp,daddr_t bn,daddr_t * bnp,int * runp,int * runb)210 ext2_bmaparray(struct vnode *vp, daddr_t bn, daddr_t *bnp, int *runp, int *runb)
211 {
212 struct inode *ip;
213 struct buf *bp;
214 struct ext2mount *ump;
215 struct mount *mp;
216 struct indir a[EXT2_NIADDR + 1], *ap;
217 daddr_t daddr;
218 e2fs_lbn_t metalbn;
219 int error, num, maxrun = 0, bsize;
220 int *nump;
221
222 ap = NULL;
223 ip = VTOI(vp);
224 mp = vp->v_mount;
225 ump = VFSTOEXT2(mp);
226
227 bsize = EXT2_BLOCK_SIZE(ump->um_e2fs);
228
229 if (runp) {
230 maxrun = mp->mnt_iosize_max / bsize - 1;
231 *runp = 0;
232 }
233 if (runb)
234 *runb = 0;
235
236 ap = a;
237 nump = #
238 error = ext2_getlbns(vp, bn, ap, nump);
239 if (error)
240 return (error);
241
242 num = *nump;
243 if (num == 0) {
244 *bnp = blkptrtodb(ump, ip->i_db[bn]);
245 if (*bnp == 0) {
246 *bnp = -1;
247 } else if (runp) {
248 daddr_t bnb = bn;
249
250 for (++bn; bn < EXT2_NDADDR && *runp < maxrun &&
251 is_sequential(ump, ip->i_db[bn - 1], ip->i_db[bn]);
252 ++bn, ++*runp);
253 bn = bnb;
254 if (runb && (bn > 0)) {
255 for (--bn; (bn >= 0) && (*runb < maxrun) &&
256 is_sequential(ump, ip->i_db[bn],
257 ip->i_db[bn + 1]);
258 --bn, ++*runb);
259 }
260 }
261 return (0);
262 }
263
264 /* Get disk address out of indirect block array */
265 daddr = ip->i_ib[ap->in_off];
266
267 for (bp = NULL, ++ap; --num; ++ap) {
268 /*
269 * Exit the loop if there is no disk address assigned yet and
270 * the indirect block isn't in the cache, or if we were
271 * looking for an indirect block and we've found it.
272 */
273
274 metalbn = ap->in_lbn;
275 if ((daddr == 0 && !incore(&vp->v_bufobj, metalbn)) || metalbn == bn)
276 break;
277 /*
278 * If we get here, we've either got the block in the cache
279 * or we have a disk address for it, go fetch it.
280 */
281 if (bp)
282 bqrelse(bp);
283 error = readindir(vp, metalbn, daddr, &bp);
284 if (error != 0)
285 return (error);
286
287 daddr = le32toh(((e2fs_daddr_t *)bp->b_data)[ap->in_off]);
288 if (num == 1 && daddr && runp) {
289 for (bn = ap->in_off + 1;
290 bn < MNINDIR(ump) && *runp < maxrun &&
291 is_sequential(ump,
292 ((e2fs_daddr_t *)bp->b_data)[bn - 1],
293 ((e2fs_daddr_t *)bp->b_data)[bn]);
294 ++bn, ++*runp);
295 bn = ap->in_off;
296 if (runb && bn) {
297 for (--bn; bn >= 0 && *runb < maxrun &&
298 is_sequential(ump,
299 ((e2fs_daddr_t *)bp->b_data)[bn],
300 ((e2fs_daddr_t *)bp->b_data)[bn + 1]);
301 --bn, ++*runb);
302 }
303 }
304 }
305 if (bp)
306 bqrelse(bp);
307
308 *bnp = blkptrtodb(ump, daddr);
309 if (*bnp == 0) {
310 *bnp = -1;
311 }
312 return (0);
313 }
314
315 static e2fs_lbn_t
lbn_count(struct ext2mount * ump,int level)316 lbn_count(struct ext2mount *ump, int level)
317
318 {
319 e2fs_lbn_t blockcnt;
320
321 for (blockcnt = 1; level > 0; level--)
322 blockcnt *= MNINDIR(ump);
323 return (blockcnt);
324 }
325
326 int
ext2_bmap_seekdata(struct vnode * vp,off_t * offp)327 ext2_bmap_seekdata(struct vnode *vp, off_t *offp)
328 {
329 struct buf *bp;
330 struct indir a[EXT2_NIADDR + 1], *ap;
331 struct inode *ip;
332 struct mount *mp;
333 struct ext2mount *ump;
334 e2fs_daddr_t bn, daddr, nextbn;
335 uint64_t bsize;
336 off_t numblks;
337 int error, num, num1, off;
338
339 bp = NULL;
340 error = 0;
341 ip = VTOI(vp);
342 mp = vp->v_mount;
343 ump = VFSTOEXT2(mp);
344
345 if (vp->v_type != VREG)
346 return (EINVAL);
347 if (*offp < 0 || *offp >= ip->i_size)
348 return (ENXIO);
349
350 bsize = mp->mnt_stat.f_iosize;
351 for (bn = *offp / bsize, numblks = howmany(ip->i_size, bsize);
352 bn < numblks; bn = nextbn) {
353 if (bn < EXT2_NDADDR) {
354 daddr = ip->i_db[bn];
355 if (daddr != 0)
356 break;
357 nextbn = bn + 1;
358 continue;
359 }
360
361 ap = a;
362 error = ext2_getlbns(vp, bn, ap, &num);
363 if (error != 0)
364 break;
365 MPASS(num >= 2);
366 daddr = ip->i_ib[ap->in_off];
367 ap++, num--;
368 for (nextbn = EXT2_NDADDR, num1 = num - 1; num1 > 0; num1--)
369 nextbn += lbn_count(ump, num1);
370 if (daddr == 0) {
371 nextbn += lbn_count(ump, num);
372 continue;
373 }
374
375 for (; daddr != 0 && num > 0; ap++, num--) {
376 if (bp != NULL)
377 bqrelse(bp);
378 error = readindir(vp, ap->in_lbn, daddr, &bp);
379 if (error != 0)
380 return (error);
381
382 /*
383 * Scan the indirect block until we find a non-zero
384 * pointer.
385 */
386 off = ap->in_off;
387 do {
388 daddr = le32toh(((e2fs_daddr_t *)bp->b_data)[off]);
389 } while (daddr == 0 && ++off < MNINDIR(ump));
390 nextbn += off * lbn_count(ump, num - 1);
391
392 /*
393 * We need to recompute the LBNs of indirect
394 * blocks, so restart with the updated block offset.
395 */
396 if (off != ap->in_off)
397 break;
398 }
399 if (num == 0) {
400 /*
401 * We found a data block.
402 */
403 bn = nextbn;
404 break;
405 }
406 }
407 if (bp != NULL)
408 bqrelse(bp);
409 if (bn >= numblks)
410 error = ENXIO;
411 if (error == 0 && *offp < bn * bsize)
412 *offp = bn * bsize;
413 return (error);
414 }
415
416 /*
417 * Create an array of logical block number/offset pairs which represent the
418 * path of indirect blocks required to access a data block. The first "pair"
419 * contains the logical block number of the appropriate single, double or
420 * triple indirect block and the offset into the inode indirect block array.
421 * Note, the logical block number of the inode single/double/triple indirect
422 * block appears twice in the array, once with the offset into the i_ib and
423 * once with the offset into the page itself.
424 */
425 int
ext2_getlbns(struct vnode * vp,daddr_t bn,struct indir * ap,int * nump)426 ext2_getlbns(struct vnode *vp, daddr_t bn, struct indir *ap, int *nump)
427 {
428 long blockcnt;
429 e2fs_lbn_t metalbn, realbn;
430 struct ext2mount *ump;
431 int i, numlevels, off;
432 int64_t qblockcnt;
433
434 ump = VFSTOEXT2(vp->v_mount);
435 if (nump)
436 *nump = 0;
437 numlevels = 0;
438 realbn = bn;
439 if ((long)bn < 0)
440 bn = -(long)bn;
441
442 /* The first EXT2_NDADDR blocks are direct blocks. */
443 if (bn < EXT2_NDADDR)
444 return (0);
445
446 /*
447 * Determine the number of levels of indirection. After this loop
448 * is done, blockcnt indicates the number of data blocks possible
449 * at the previous level of indirection, and EXT2_NIADDR - i is the
450 * number of levels of indirection needed to locate the requested block.
451 */
452 for (blockcnt = 1, i = EXT2_NIADDR, bn -= EXT2_NDADDR; ;
453 i--, bn -= blockcnt) {
454 if (i == 0)
455 return (EFBIG);
456 /*
457 * Use int64_t's here to avoid overflow for triple indirect
458 * blocks when longs have 32 bits and the block size is more
459 * than 4K.
460 */
461 qblockcnt = (int64_t)blockcnt * MNINDIR(ump);
462 if (bn < qblockcnt)
463 break;
464 blockcnt = qblockcnt;
465 }
466
467 /* Calculate the address of the first meta-block. */
468 if (realbn >= 0)
469 metalbn = -(realbn - bn + EXT2_NIADDR - i);
470 else
471 metalbn = -(-realbn - bn + EXT2_NIADDR - i);
472
473 /*
474 * At each iteration, off is the offset into the bap array which is
475 * an array of disk addresses at the current level of indirection.
476 * The logical block number and the offset in that block are stored
477 * into the argument array.
478 */
479 ap->in_lbn = metalbn;
480 ap->in_off = off = EXT2_NIADDR - i;
481 ap++;
482 for (++numlevels; i <= EXT2_NIADDR; i++) {
483 /* If searching for a meta-data block, quit when found. */
484 if (metalbn == realbn)
485 break;
486
487 off = (bn / blockcnt) % MNINDIR(ump);
488
489 ++numlevels;
490 ap->in_lbn = metalbn;
491 ap->in_off = off;
492 ++ap;
493
494 metalbn -= -1 + off * blockcnt;
495 blockcnt /= MNINDIR(ump);
496 }
497 if (nump)
498 *nump = numlevels;
499 return (0);
500 }
501