1 /*-
2 * Copyright (c) 1989, 1991, 1993
3 * The Regents of the University of California. All rights reserved.
4 * (c) UNIX System Laboratories, Inc.
5 * All or some portions of this file are derived from material licensed
6 * to the University of California by American Telephone and Telegraph
7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
8 * the permission of UNIX System Laboratories, Inc.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 4. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 * @(#)ufs_bmap.c 8.7 (Berkeley) 3/21/95
35 * $FreeBSD: releng/10.2/sys/fs/ext2fs/ext2_bmap.c 278096 2015-02-02 15:52:11Z pfg $
36 */
37
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/bio.h>
41 #include <sys/buf.h>
42 #include <sys/proc.h>
43 #include <sys/vnode.h>
44 #include <sys/mount.h>
45 #include <sys/resourcevar.h>
46 #include <sys/stat.h>
47
48 #include <fs/ext2fs/inode.h>
49 #include <fs/ext2fs/fs.h>
50 #include <fs/ext2fs/ext2fs.h>
51 #include <fs/ext2fs/ext2_dinode.h>
52 #include <fs/ext2fs/ext2_extern.h>
53 #include <fs/ext2fs/ext2_mount.h>
54
55 static int ext4_bmapext(struct vnode *, int32_t, int64_t *, int *, int *);
56
57 /*
58 * Bmap converts the logical block number of a file to its physical block
59 * number on the disk. The conversion is done by using the logical block
60 * number to index into the array of block pointers described by the dinode.
61 */
62 int
63 ext2_bmap(struct vop_bmap_args *ap)
64 {
65 daddr_t blkno;
66 int error;
67
68 /*
69 * Check for underlying vnode requests and ensure that logical
70 * to physical mapping is requested.
71 */
72 if (ap->a_bop != NULL)
73 *ap->a_bop = &VTOI(ap->a_vp)->i_devvp->v_bufobj;
74 if (ap->a_bnp == NULL)
75 return (0);
76
77 if (VTOI(ap->a_vp)->i_flag & IN_E4EXTENTS)
78 error = ext4_bmapext(ap->a_vp, ap->a_bn, &blkno,
79 ap->a_runp, ap->a_runb);
80 else
81 error = ext2_bmaparray(ap->a_vp, ap->a_bn, &blkno,
82 ap->a_runp, ap->a_runb);
83 *ap->a_bnp = blkno;
84 return (error);
85 }
86
87 /*
88 * This function converts the logical block number of a file to
89 * its physical block number on the disk within ext4 extents.
90 */
91 static int
92 ext4_bmapext(struct vnode *vp, int32_t bn, int64_t *bnp, int *runp, int *runb)
93 {
94 struct inode *ip;
95 struct m_ext2fs *fs;
96 struct ext4_extent *ep;
97 struct ext4_extent_path path = { .ep_bp = NULL };
98 daddr_t lbn;
99
100 ip = VTOI(vp);
101 fs = ip->i_e2fs;
102 lbn = bn;
103
104 /*
105 * TODO: need to implement read ahead to improve the performance.
106 */
107 if (runp != NULL)
108 *runp = 0;
109
110 if (runb != NULL)
111 *runb = 0;
112
113 ext4_ext_find_extent(fs, ip, lbn, &path);
114 ep = path.ep_ext;
115 if (ep == NULL)
116 return (EIO);
117
118 *bnp = fsbtodb(fs, lbn - ep->e_blk +
119 (ep->e_start_lo | (daddr_t)ep->e_start_hi << 32));
120
121 if (*bnp == 0)
122 *bnp = -1;
123
124 return (0);
125 }
126
127 /*
128 * Indirect blocks are now on the vnode for the file. They are given negative
129 * logical block numbers. Indirect blocks are addressed by the negative
130 * address of the first data block to which they point. Double indirect blocks
131 * are addressed by one less than the address of the first indirect block to
132 * which they point. Triple indirect blocks are addressed by one less than
133 * the address of the first double indirect block to which they point.
134 *
135 * ext2_bmaparray does the bmap conversion, and if requested returns the
136 * array of logical blocks which must be traversed to get to a block.
137 * Each entry contains the offset into that block that gets you to the
138 * next block and the disk address of the block (if it is assigned).
139 */
140
141 int
142 ext2_bmaparray(struct vnode *vp, daddr_t bn, daddr_t *bnp, int *runp, int *runb)
143 {
144 struct inode *ip;
145 struct buf *bp;
146 struct ext2mount *ump;
147 struct mount *mp;
148 struct indir a[NIADDR+1], *ap;
149 daddr_t daddr;
150 e2fs_lbn_t metalbn;
151 int error, num, maxrun = 0, bsize;
152 int *nump;
153
154 ap = NULL;
155 ip = VTOI(vp);
156 mp = vp->v_mount;
157 ump = VFSTOEXT2(mp);
158
159 bsize = EXT2_BLOCK_SIZE(ump->um_e2fs);
160
161 if (runp) {
162 maxrun = mp->mnt_iosize_max / bsize - 1;
163 *runp = 0;
164 }
165
166 if (runb) {
167 *runb = 0;
168 }
169
170
171 ap = a;
172 nump = #
173 error = ext2_getlbns(vp, bn, ap, nump);
174 if (error)
175 return (error);
176
177 num = *nump;
178 if (num == 0) {
179 *bnp = blkptrtodb(ump, ip->i_db[bn]);
180 if (*bnp == 0) {
181 *bnp = -1;
182 } else if (runp) {
183 daddr_t bnb = bn;
184 for (++bn; bn < NDADDR && *runp < maxrun &&
185 is_sequential(ump, ip->i_db[bn - 1], ip->i_db[bn]);
186 ++bn, ++*runp);
187 bn = bnb;
188 if (runb && (bn > 0)) {
189 for (--bn; (bn >= 0) && (*runb < maxrun) &&
190 is_sequential(ump, ip->i_db[bn],
191 ip->i_db[bn + 1]);
192 --bn, ++*runb);
193 }
194 }
195 return (0);
196 }
197
198
199 /* Get disk address out of indirect block array */
200 daddr = ip->i_ib[ap->in_off];
201
202 for (bp = NULL, ++ap; --num; ++ap) {
203 /*
204 * Exit the loop if there is no disk address assigned yet and
205 * the indirect block isn't in the cache, or if we were
206 * looking for an indirect block and we've found it.
207 */
208
209 metalbn = ap->in_lbn;
210 if ((daddr == 0 && !incore(&vp->v_bufobj, metalbn)) || metalbn == bn)
211 break;
212 /*
213 * If we get here, we've either got the block in the cache
214 * or we have a disk address for it, go fetch it.
215 */
216 if (bp)
217 bqrelse(bp);
218
219 bp = getblk(vp, metalbn, bsize, 0, 0, 0);
220 if ((bp->b_flags & B_CACHE) == 0) {
221 #ifdef INVARIANTS
222 if (!daddr)
223 panic("ext2_bmaparray: indirect block not in cache");
224 #endif
225 bp->b_blkno = blkptrtodb(ump, daddr);
226 bp->b_iocmd = BIO_READ;
227 bp->b_flags &= ~B_INVAL;
228 bp->b_ioflags &= ~BIO_ERROR;
229 vfs_busy_pages(bp, 0);
230 bp->b_iooffset = dbtob(bp->b_blkno);
231 bstrategy(bp);
232 curthread->td_ru.ru_inblock++;
233 error = bufwait(bp);
234 if (error) {
235 brelse(bp);
236 return (error);
237 }
238 }
239
240 daddr = ((e2fs_daddr_t *)bp->b_data)[ap->in_off];
241 if (num == 1 && daddr && runp) {
242 for (bn = ap->in_off + 1;
243 bn < MNINDIR(ump) && *runp < maxrun &&
244 is_sequential(ump,
245 ((e2fs_daddr_t *)bp->b_data)[bn - 1],
246 ((e2fs_daddr_t *)bp->b_data)[bn]);
247 ++bn, ++*runp);
248 bn = ap->in_off;
249 if (runb && bn) {
250 for (--bn; bn >= 0 && *runb < maxrun &&
251 is_sequential(ump,
252 ((e2fs_daddr_t *)bp->b_data)[bn],
253 ((e2fs_daddr_t *)bp->b_data)[bn + 1]);
254 --bn, ++*runb);
255 }
256 }
257 }
258 if (bp)
259 bqrelse(bp);
260
261 /*
262 * Since this is FFS independent code, we are out of scope for the
263 * definitions of BLK_NOCOPY and BLK_SNAP, but we do know that they
264 * will fall in the range 1..um_seqinc, so we use that test and
265 * return a request for a zeroed out buffer if attempts are made
266 * to read a BLK_NOCOPY or BLK_SNAP block.
267 */
268 if ((ip->i_flags & SF_SNAPSHOT) && daddr > 0 && daddr < ump->um_seqinc){
269 *bnp = -1;
270 return (0);
271 }
272 *bnp = blkptrtodb(ump, daddr);
273 if (*bnp == 0) {
274 *bnp = -1;
275 }
276 return (0);
277 }
278
279 /*
280 * Create an array of logical block number/offset pairs which represent the
281 * path of indirect blocks required to access a data block. The first "pair"
282 * contains the logical block number of the appropriate single, double or
283 * triple indirect block and the offset into the inode indirect block array.
284 * Note, the logical block number of the inode single/double/triple indirect
285 * block appears twice in the array, once with the offset into the i_ib and
286 * once with the offset into the page itself.
287 */
288 int
289 ext2_getlbns(struct vnode *vp, daddr_t bn, struct indir *ap, int *nump)
290 {
291 long blockcnt;
292 e2fs_lbn_t metalbn, realbn;
293 struct ext2mount *ump;
294 int i, numlevels, off;
295 int64_t qblockcnt;
296
297 ump = VFSTOEXT2(vp->v_mount);
298 if (nump)
299 *nump = 0;
300 numlevels = 0;
301 realbn = bn;
302 if ((long)bn < 0)
303 bn = -(long)bn;
304
305 /* The first NDADDR blocks are direct blocks. */
306 if (bn < NDADDR)
307 return (0);
308
309 /*
310 * Determine the number of levels of indirection. After this loop
311 * is done, blockcnt indicates the number of data blocks possible
312 * at the previous level of indirection, and NIADDR - i is the number
313 * of levels of indirection needed to locate the requested block.
314 */
315 for (blockcnt = 1, i = NIADDR, bn -= NDADDR;; i--, bn -= blockcnt) {
316 if (i == 0)
317 return (EFBIG);
318 /*
319 * Use int64_t's here to avoid overflow for triple indirect
320 * blocks when longs have 32 bits and the block size is more
321 * than 4K.
322 */
323 qblockcnt = (int64_t)blockcnt * MNINDIR(ump);
324 if (bn < qblockcnt)
325 break;
326 blockcnt = qblockcnt;
327 }
328
329 /* Calculate the address of the first meta-block. */
330 if (realbn >= 0)
331 metalbn = -(realbn - bn + NIADDR - i);
332 else
333 metalbn = -(-realbn - bn + NIADDR - i);
334
335 /*
336 * At each iteration, off is the offset into the bap array which is
337 * an array of disk addresses at the current level of indirection.
338 * The logical block number and the offset in that block are stored
339 * into the argument array.
340 */
341 ap->in_lbn = metalbn;
342 ap->in_off = off = NIADDR - i;
343 ap++;
344 for (++numlevels; i <= NIADDR; i++) {
345 /* If searching for a meta-data block, quit when found. */
346 if (metalbn == realbn)
347 break;
348
349 off = (bn / blockcnt) % MNINDIR(ump);
350
351 ++numlevels;
352 ap->in_lbn = metalbn;
353 ap->in_off = off;
354 ++ap;
355
356 metalbn -= -1 + off * blockcnt;
357 blockcnt /= MNINDIR(ump);
358 }
359 if (nump)
360 *nump = numlevels;
361 return (0);
362 }
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