Annotation of sys/ufs/ufs/ufs_bmap.c, Revision 1.1.1.1
1.1 nbrk 1: /* $OpenBSD: ufs_bmap.c,v 1.25 2007/06/01 23:47:57 deraadt Exp $ */
2: /* $NetBSD: ufs_bmap.c,v 1.3 1996/02/09 22:36:00 christos 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 8.6 (Berkeley) 1/21/94
38: */
39:
40: #include <sys/param.h>
41: #include <sys/systm.h>
42: #include <sys/buf.h>
43: #include <sys/proc.h>
44: #include <sys/vnode.h>
45: #include <sys/mount.h>
46: #include <sys/resourcevar.h>
47:
48: #include <miscfs/specfs/specdev.h>
49:
50: #include <ufs/ufs/quota.h>
51: #include <ufs/ufs/inode.h>
52: #include <ufs/ufs/ufsmount.h>
53: #include <ufs/ufs/ufs_extern.h>
54:
55: /*
56: * Bmap converts a the logical block number of a file to its physical block
57: * number on the disk. The conversion is done by using the logical block
58: * number to index into the array of block pointers described by the dinode.
59: */
60: int
61: ufs_bmap(void *v)
62: {
63: struct vop_bmap_args *ap = v;
64:
65: /*
66: * Check for underlying vnode requests and ensure that logical
67: * to physical mapping is requested.
68: */
69: if (ap->a_vpp != NULL)
70: *ap->a_vpp = VTOI(ap->a_vp)->i_devvp;
71: if (ap->a_bnp == NULL)
72: return (0);
73:
74: return (ufs_bmaparray(ap->a_vp, ap->a_bn, ap->a_bnp, NULL, NULL,
75: ap->a_runp));
76: }
77:
78: /*
79: * Indirect blocks are now on the vnode for the file. They are given negative
80: * logical block numbers. Indirect blocks are addressed by the negative
81: * address of the first data block to which they point. Double indirect blocks
82: * are addressed by one less than the address of the first indirect block to
83: * which they point. Triple indirect blocks are addressed by one less than
84: * the address of the first double indirect block to which they point.
85: *
86: * ufs_bmaparray does the bmap conversion, and if requested returns the
87: * array of logical blocks which must be traversed to get to a block.
88: * Each entry contains the offset into that block that gets you to the
89: * next block and the disk address of the block (if it is assigned).
90: */
91: int
92: ufs_bmaparray(struct vnode *vp, daddr_t bn, daddr64_t *bnp, struct indir *ap,
93: int *nump, int *runp)
94: {
95: struct inode *ip;
96: struct buf *bp;
97: struct ufsmount *ump;
98: struct mount *mp;
99: struct vnode *devvp;
100: struct indir a[NIADDR+1], *xap;
101: daddr64_t daddr;
102: long metalbn;
103: int error, maxrun = 0, num;
104:
105: ip = VTOI(vp);
106: mp = vp->v_mount;
107: ump = VFSTOUFS(mp);
108: #ifdef DIAGNOSTIC
109: if ((ap != NULL && nump == NULL) || (ap == NULL && nump != NULL))
110: panic("ufs_bmaparray: invalid arguments");
111: #endif
112:
113: if (runp) {
114: /*
115: * XXX
116: * If MAXBSIZE is the largest transfer the disks can handle,
117: * we probably want maxrun to be 1 block less so that we
118: * don't create a block larger than the device can handle.
119: */
120: *runp = 0;
121: maxrun = MAXBSIZE / mp->mnt_stat.f_iosize - 1;
122: }
123:
124: xap = ap == NULL ? a : ap;
125: if (!nump)
126: nump = #
127: if ((error = ufs_getlbns(vp, bn, xap, nump)) != 0)
128: return (error);
129:
130: num = *nump;
131: if (num == 0) {
132: *bnp = blkptrtodb(ump, DIP(ip, db[bn]));
133: if (*bnp == 0)
134: *bnp = -1;
135: else if (runp)
136: for (++bn; bn < NDADDR && *runp < maxrun &&
137: is_sequential(ump, DIP(ip, db[bn - 1]),
138: DIP(ip, db[bn]));
139: ++bn, ++*runp);
140: return (0);
141: }
142:
143:
144: /* Get disk address out of indirect block array */
145: daddr = DIP(ip, ib[xap->in_off]);
146:
147: devvp = VFSTOUFS(vp->v_mount)->um_devvp;
148: for (bp = NULL, ++xap; --num; ++xap) {
149: /*
150: * Exit the loop if there is no disk address assigned yet and
151: * the indirect block isn't in the cache, or if we were
152: * looking for an indirect block and we've found it.
153: */
154:
155: metalbn = xap->in_lbn;
156: if ((daddr == 0 && !incore(vp, metalbn)) || metalbn == bn)
157: break;
158: /*
159: * If we get here, we've either got the block in the cache
160: * or we have a disk address for it, go fetch it.
161: */
162: if (bp)
163: brelse(bp);
164:
165: xap->in_exists = 1;
166: bp = getblk(vp, metalbn, mp->mnt_stat.f_iosize, 0, 0);
167: if (bp->b_flags & (B_DONE | B_DELWRI)) {
168: ;
169: }
170: #ifdef DIAGNOSTIC
171: else if (!daddr)
172: panic("ufs_bmaparray: indirect block not in cache");
173: #endif
174: else {
175: bp->b_blkno = blkptrtodb(ump, daddr);
176: bp->b_flags |= B_READ;
177: VOP_STRATEGY(bp);
178: curproc->p_stats->p_ru.ru_inblock++; /* XXX */
179: if ((error = biowait(bp)) != 0) {
180: brelse(bp);
181: return (error);
182: }
183: }
184:
185: #ifdef FFS2
186: if (ip->i_ump->um_fstype == UM_UFS2) {
187: daddr = ((daddr64_t *)bp->b_data)[xap->in_off];
188: if (num == 1 && daddr && runp)
189: for (bn = xap->in_off + 1;
190: bn < MNINDIR(ump) && *runp < maxrun &&
191: is_sequential(ump,
192: ((daddr64_t *)bp->b_data)[bn - 1],
193: ((daddr64_t *)bp->b_data)[bn]);
194: ++bn, ++*runp);
195:
196: continue;
197: }
198:
199: #endif /* FFS2 */
200:
201: daddr = ((daddr_t *)bp->b_data)[xap->in_off];
202: if (num == 1 && daddr && runp)
203: for (bn = xap->in_off + 1;
204: bn < MNINDIR(ump) && *runp < maxrun &&
205: is_sequential(ump,
206: ((daddr_t *)bp->b_data)[bn - 1],
207: ((daddr_t *)bp->b_data)[bn]);
208: ++bn, ++*runp);
209: }
210: if (bp)
211: brelse(bp);
212:
213: daddr = blkptrtodb(ump, daddr);
214: *bnp = daddr == 0 ? -1 : daddr;
215: return (0);
216: }
217:
218: /*
219: * Create an array of logical block number/offset pairs which represent the
220: * path of indirect blocks required to access a data block. The first "pair"
221: * contains the logical block number of the appropriate single, double or
222: * triple indirect block and the offset into the inode indirect block array.
223: * Note, the logical block number of the inode single/double/triple indirect
224: * block appears twice in the array, once with the offset into the i_ffs_ib and
225: * once with the offset into the page itself.
226: */
227: int
228: ufs_getlbns(struct vnode *vp, daddr_t bn, struct indir *ap, int *nump)
229: {
230: long metalbn, realbn;
231: struct ufsmount *ump;
232: int64_t blockcnt;
233: int i, numlevels, off;
234:
235: ump = VFSTOUFS(vp->v_mount);
236: if (nump)
237: *nump = 0;
238: numlevels = 0;
239: realbn = bn;
240: if ((long)bn < 0)
241: bn = -(long)bn;
242:
243: #ifdef DIAGNOSTIC
244: if (realbn < 0 && realbn > -NDADDR) {
245: panic ("ufs_getlbns: Invalid indirect block %d specified",
246: realbn);
247: }
248: #endif
249:
250: /* The first NDADDR blocks are direct blocks. */
251: if (bn < NDADDR)
252: return (0);
253:
254: /*
255: * Determine the number of levels of indirection. After this loop
256: * is done, blockcnt indicates the number of data blocks possible
257: * at the given level of indirection, and NIADDR - i is the number
258: * of levels of indirection needed to locate the requested block.
259: */
260: for (blockcnt = 1, i = NIADDR, bn -= NDADDR;; i--, bn -= blockcnt) {
261: if (i == 0)
262: return (EFBIG);
263: blockcnt *= MNINDIR(ump);
264: if (bn < blockcnt)
265: break;
266: }
267:
268: /* Calculate the address of the first meta-block. */
269: if (realbn >= 0)
270: metalbn = -(realbn - bn + NIADDR - i);
271: else
272: metalbn = -(-realbn - bn + NIADDR - i);
273:
274: /*
275: * At each iteration, off is the offset into the bap array which is
276: * an array of disk addresses at the current level of indirection.
277: * The logical block number and the offset in that block are stored
278: * into the argument array.
279: */
280: ap->in_lbn = metalbn;
281: ap->in_off = off = NIADDR - i;
282: ap->in_exists = 0;
283: ap++;
284: for (++numlevels; i <= NIADDR; i++) {
285: /* If searching for a meta-data block, quit when found. */
286: if (metalbn == realbn)
287: break;
288:
289: blockcnt /= MNINDIR(ump);
290: off = (bn / blockcnt) % MNINDIR(ump);
291:
292: ++numlevels;
293: ap->in_lbn = metalbn;
294: ap->in_off = off;
295: ap->in_exists = 0;
296: ++ap;
297:
298: metalbn -= -1 + off * blockcnt;
299: }
300: #ifdef DIAGNOSTIC
301: if (realbn < 0 && metalbn != realbn) {
302: panic("ufs_getlbns: indirect block %d not found", realbn);
303: }
304: #endif
305: if (nump)
306: *nump = numlevels;
307: return (0);
308: }
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