Commit | Line | Data |
---|---|---|
da7c5cc6 | 1 | /* |
0880b18e | 2 | * Copyright (c) 1982, 1986 Regents of the University of California. |
da7c5cc6 KM |
3 | * All rights reserved. The Berkeley software License Agreement |
4 | * specifies the terms and conditions for redistribution. | |
5 | * | |
95f51977 | 6 | * @(#)ufs_bmap.c 7.1 (Berkeley) 6/5/86 |
da7c5cc6 | 7 | */ |
52212483 | 8 | |
94368568 JB |
9 | #include "param.h" |
10 | #include "systm.h" | |
94368568 JB |
11 | #include "inode.h" |
12 | #include "dir.h" | |
13 | #include "user.h" | |
14 | #include "buf.h" | |
15 | #include "proc.h" | |
16 | #include "fs.h" | |
52212483 BJ |
17 | |
18 | /* | |
19 | * Bmap defines the structure of file system storage | |
20 | * by returning the physical block number on a device given the | |
21 | * inode and the logical block number in a file. | |
22 | * When convenient, it also leaves the physical | |
23 | * block number of the next block of the file in rablock | |
24 | * for use in read-ahead. | |
25 | */ | |
26 | /*VARARGS3*/ | |
27 | daddr_t | |
28 | bmap(ip, bn, rwflg, size) | |
29 | register struct inode *ip; | |
30 | daddr_t bn; | |
31 | int rwflg; | |
32 | int size; /* supplied only when rwflg == B_WRITE */ | |
33 | { | |
34 | register int i; | |
35 | int osize, nsize; | |
36 | struct buf *bp, *nbp; | |
37 | struct fs *fs; | |
38 | int j, sh; | |
a6e7e3c6 | 39 | daddr_t nb, lbn, *bap, pref, blkpref(); |
52212483 BJ |
40 | |
41 | if (bn < 0) { | |
42 | u.u_error = EFBIG; | |
43 | return ((daddr_t)0); | |
44 | } | |
45 | fs = ip->i_fs; | |
46 | rablock = 0; | |
47 | rasize = 0; /* conservative */ | |
48 | ||
49 | /* | |
50 | * If the next write will extend the file into a new block, | |
51 | * and the file is currently composed of a fragment | |
52 | * this fragment has to be extended to be a full block. | |
53 | */ | |
54 | nb = lblkno(fs, ip->i_size); | |
55 | if (rwflg == B_WRITE && nb < NDADDR && nb < bn) { | |
56 | osize = blksize(fs, ip, nb); | |
57 | if (osize < fs->fs_bsize && osize > 0) { | |
58 | bp = realloccg(ip, ip->i_db[nb], | |
4f083fd7 SL |
59 | blkpref(ip, nb, (int)nb, &ip->i_db[0]), |
60 | osize, (int)fs->fs_bsize); | |
ef916aa8 SL |
61 | if (bp == NULL) |
62 | return ((daddr_t)-1); | |
52212483 BJ |
63 | ip->i_size = (nb + 1) * fs->fs_bsize; |
64 | ip->i_db[nb] = dbtofsb(fs, bp->b_blkno); | |
65 | ip->i_flag |= IUPD|ICHG; | |
66 | bdwrite(bp); | |
67 | } | |
68 | } | |
69 | /* | |
70 | * The first NDADDR blocks are direct blocks | |
71 | */ | |
72 | if (bn < NDADDR) { | |
a6e7e3c6 | 73 | nb = ip->i_db[bn]; |
52212483 BJ |
74 | if (rwflg == B_READ) { |
75 | if (nb == 0) | |
76 | return ((daddr_t)-1); | |
77 | goto gotit; | |
78 | } | |
a6e7e3c6 | 79 | if (nb == 0 || ip->i_size < (bn + 1) * fs->fs_bsize) { |
52212483 BJ |
80 | if (nb != 0) { |
81 | /* consider need to reallocate a frag */ | |
82 | osize = fragroundup(fs, blkoff(fs, ip->i_size)); | |
83 | nsize = fragroundup(fs, size); | |
84 | if (nsize <= osize) | |
85 | goto gotit; | |
a6e7e3c6 | 86 | bp = realloccg(ip, nb, |
4f083fd7 | 87 | blkpref(ip, bn, (int)bn, &ip->i_db[0]), |
52212483 BJ |
88 | osize, nsize); |
89 | } else { | |
a6e7e3c6 | 90 | if (ip->i_size < (bn + 1) * fs->fs_bsize) |
52212483 BJ |
91 | nsize = fragroundup(fs, size); |
92 | else | |
93 | nsize = fs->fs_bsize; | |
a6e7e3c6 | 94 | bp = alloc(ip, |
4f083fd7 | 95 | blkpref(ip, bn, (int)bn, &ip->i_db[0]), |
52212483 BJ |
96 | nsize); |
97 | } | |
98 | if (bp == NULL) | |
99 | return ((daddr_t)-1); | |
100 | nb = dbtofsb(fs, bp->b_blkno); | |
101 | if ((ip->i_mode&IFMT) == IFDIR) | |
102 | /* | |
103 | * Write directory blocks synchronously | |
104 | * so they never appear with garbage in | |
105 | * them on the disk. | |
106 | */ | |
107 | bwrite(bp); | |
108 | else | |
109 | bdwrite(bp); | |
a6e7e3c6 | 110 | ip->i_db[bn] = nb; |
52212483 BJ |
111 | ip->i_flag |= IUPD|ICHG; |
112 | } | |
113 | gotit: | |
a6e7e3c6 KM |
114 | if (bn < NDADDR - 1) { |
115 | rablock = fsbtodb(fs, ip->i_db[bn + 1]); | |
116 | rasize = blksize(fs, ip, bn + 1); | |
52212483 BJ |
117 | } |
118 | return (nb); | |
119 | } | |
120 | ||
121 | /* | |
122 | * Determine how many levels of indirection. | |
123 | */ | |
a6e7e3c6 | 124 | pref = 0; |
52212483 | 125 | sh = 1; |
a6e7e3c6 | 126 | lbn = bn; |
52212483 BJ |
127 | bn -= NDADDR; |
128 | for (j = NIADDR; j>0; j--) { | |
129 | sh *= NINDIR(fs); | |
130 | if (bn < sh) | |
131 | break; | |
132 | bn -= sh; | |
133 | } | |
134 | if (j == 0) { | |
135 | u.u_error = EFBIG; | |
136 | return ((daddr_t)0); | |
137 | } | |
138 | ||
139 | /* | |
140 | * fetch the first indirect block | |
141 | */ | |
142 | nb = ip->i_ib[NIADDR - j]; | |
143 | if (nb == 0) { | |
a6e7e3c6 KM |
144 | if (rwflg == B_READ) |
145 | return ((daddr_t)-1); | |
4f083fd7 SL |
146 | pref = blkpref(ip, lbn, 0, (daddr_t *)0); |
147 | bp = alloc(ip, pref, (int)fs->fs_bsize); | |
a6e7e3c6 | 148 | if (bp == NULL) |
52212483 BJ |
149 | return ((daddr_t)-1); |
150 | nb = dbtofsb(fs, bp->b_blkno); | |
151 | /* | |
152 | * Write synchronously so that indirect blocks | |
153 | * never point at garbage. | |
154 | */ | |
155 | bwrite(bp); | |
156 | ip->i_ib[NIADDR - j] = nb; | |
157 | ip->i_flag |= IUPD|ICHG; | |
158 | } | |
159 | ||
160 | /* | |
161 | * fetch through the indirect blocks | |
162 | */ | |
163 | for (; j <= NIADDR; j++) { | |
4f083fd7 | 164 | bp = bread(ip->i_dev, fsbtodb(fs, nb), (int)fs->fs_bsize); |
52212483 BJ |
165 | if (bp->b_flags & B_ERROR) { |
166 | brelse(bp); | |
167 | return ((daddr_t)0); | |
168 | } | |
169 | bap = bp->b_un.b_daddr; | |
170 | sh /= NINDIR(fs); | |
171 | i = (bn / sh) % NINDIR(fs); | |
172 | nb = bap[i]; | |
173 | if (nb == 0) { | |
174 | if (rwflg==B_READ) { | |
175 | brelse(bp); | |
176 | return ((daddr_t)-1); | |
177 | } | |
a6e7e3c6 KM |
178 | if (pref == 0) |
179 | if (j < NIADDR) | |
4f083fd7 SL |
180 | pref = blkpref(ip, lbn, 0, |
181 | (daddr_t *)0); | |
a6e7e3c6 KM |
182 | else |
183 | pref = blkpref(ip, lbn, i, &bap[0]); | |
4f083fd7 | 184 | nbp = alloc(ip, pref, (int)fs->fs_bsize); |
52212483 BJ |
185 | if (nbp == NULL) { |
186 | brelse(bp); | |
187 | return ((daddr_t)-1); | |
188 | } | |
189 | nb = dbtofsb(fs, nbp->b_blkno); | |
190 | if (j < NIADDR || (ip->i_mode&IFMT) == IFDIR) | |
191 | /* | |
192 | * Write synchronously so indirect blocks | |
193 | * never point at garbage and blocks | |
194 | * in directories never contain garbage. | |
195 | */ | |
196 | bwrite(nbp); | |
197 | else | |
198 | bdwrite(nbp); | |
199 | bap[i] = nb; | |
200 | bdwrite(bp); | |
201 | } else | |
202 | brelse(bp); | |
203 | } | |
204 | ||
205 | /* | |
206 | * calculate read-ahead. | |
207 | */ | |
208 | if (i < NINDIR(fs) - 1) { | |
209 | rablock = fsbtodb(fs, bap[i+1]); | |
210 | rasize = fs->fs_bsize; | |
211 | } | |
212 | return (nb); | |
213 | } |