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38 * @(#)ufs_bmap.c 8.7 (Berkeley) 3/21/95
39 * $FreeBSD: src/sys/ufs/ufs/ufs_bmap.c,v 1.34.2.1 2000/03/17 10:12:14 ps Exp $
40 * $DragonFly: src/sys/vfs/ufs/ufs_bmap.c,v 1.3 2003/06/26 20:27:53 dillon Exp $
43 #include <sys/param.h>
44 #include <sys/systm.h>
47 #include <sys/vnode.h>
48 #include <sys/mount.h>
49 #include <sys/resourcevar.h>
52 #include <ufs/ufs/quota.h>
53 #include <ufs/ufs/inode.h>
54 #include <ufs/ufs/ufsmount.h>
55 #include <ufs/ufs/ufs_extern.h>
58 * Bmap converts a 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.
64 struct vop_bmap_args /* {
74 * Check for underlying vnode requests and ensure that logical
75 * to physical mapping is requested.
77 if (ap->a_vpp != NULL)
78 *ap->a_vpp = VTOI(ap->a_vp)->i_devvp;
79 if (ap->a_bnp == NULL)
82 return (ufs_bmaparray(ap->a_vp, ap->a_bn, ap->a_bnp, NULL, NULL,
83 ap->a_runp, ap->a_runb));
87 * Indirect blocks are now on the vnode for the file. They are given negative
88 * logical block numbers. Indirect blocks are addressed by the negative
89 * address of the first data block to which they point. Double indirect blocks
90 * are addressed by one less than the address of the first indirect block to
91 * which they point. Triple indirect blocks are addressed by one less than
92 * the address of the first double indirect block to which they point.
94 * ufs_bmaparray does the bmap conversion, and if requested returns the
95 * array of logical blocks which must be traversed to get to a block.
96 * Each entry contains the offset into that block that gets you to the
97 * next block and the disk address of the block (if it is assigned).
101 ufs_bmaparray(vp, bn, bnp, ap, nump, runp, runb)
110 register struct inode *ip;
112 struct ufsmount *ump;
115 struct indir a[NIADDR+1], *xap;
118 int error, maxrun, num;
123 devvp = ump->um_devvp;
125 if ((ap != NULL && nump == NULL) || (ap == NULL && nump != NULL))
126 panic("ufs_bmaparray: invalid arguments");
137 maxrun = mp->mnt_iosize_max / mp->mnt_stat.f_iosize - 1;
139 xap = ap == NULL ? a : ap;
142 error = ufs_getlbns(vp, bn, xap, nump);
148 *bnp = blkptrtodb(ump, ip->i_db[bn]);
153 for (++bn; bn < NDADDR && *runp < maxrun &&
154 is_sequential(ump, ip->i_db[bn - 1], ip->i_db[bn]);
157 if (runb && (bn > 0)) {
158 for (--bn; (bn >= 0) && (*runb < maxrun) &&
159 is_sequential(ump, ip->i_db[bn],
168 /* Get disk address out of indirect block array */
169 daddr = ip->i_ib[xap->in_off];
171 for (bp = NULL, ++xap; --num; ++xap) {
173 * Exit the loop if there is no disk address assigned yet and
174 * the indirect block isn't in the cache, or if we were
175 * looking for an indirect block and we've found it.
178 metalbn = xap->in_lbn;
179 if ((daddr == 0 && !incore(vp, metalbn)) || metalbn == bn)
182 * If we get here, we've either got the block in the cache
183 * or we have a disk address for it, go fetch it.
189 bp = getblk(vp, metalbn, mp->mnt_stat.f_iosize, 0, 0);
190 if ((bp->b_flags & B_CACHE) == 0) {
193 panic("ufs_bmaparray: indirect block not in cache");
195 bp->b_blkno = blkptrtodb(ump, daddr);
196 bp->b_flags |= B_READ;
197 bp->b_flags &= ~(B_INVAL|B_ERROR);
198 vfs_busy_pages(bp, 0);
199 VOP_STRATEGY(bp->b_vp, bp);
207 daddr = ((ufs_daddr_t *)bp->b_data)[xap->in_off];
208 if (num == 1 && daddr && runp) {
209 for (bn = xap->in_off + 1;
210 bn < MNINDIR(ump) && *runp < maxrun &&
212 ((ufs_daddr_t *)bp->b_data)[bn - 1],
213 ((ufs_daddr_t *)bp->b_data)[bn]);
217 for(--bn; bn >= 0 && *runb < maxrun &&
218 is_sequential(ump, ((daddr_t *)bp->b_data)[bn],
219 ((daddr_t *)bp->b_data)[bn+1]);
227 daddr = blkptrtodb(ump, daddr);
228 *bnp = daddr == 0 ? -1 : daddr;
233 * Create an array of logical block number/offset pairs which represent the
234 * path of indirect blocks required to access a data block. The first "pair"
235 * contains the logical block number of the appropriate single, double or
236 * triple indirect block and the offset into the inode indirect block array.
237 * Note, the logical block number of the inode single/double/triple indirect
238 * block appears twice in the array, once with the offset into the i_ib and
239 * once with the offset into the page itself.
242 ufs_getlbns(vp, bn, ap, nump)
248 long blockcnt, metalbn, realbn;
249 struct ufsmount *ump;
250 int i, numlevels, off;
253 ump = VFSTOUFS(vp->v_mount);
261 /* The first NDADDR blocks are direct blocks. */
266 * Determine the number of levels of indirection. After this loop
267 * is done, blockcnt indicates the number of data blocks possible
268 * at the previous level of indirection, and NIADDR - i is the number
269 * of levels of indirection needed to locate the requested block.
271 for (blockcnt = 1, i = NIADDR, bn -= NDADDR;; i--, bn -= blockcnt) {
275 * Use int64_t's here to avoid overflow for triple indirect
276 * blocks when longs have 32 bits and the block size is more
279 qblockcnt = (int64_t)blockcnt * MNINDIR(ump);
282 blockcnt = qblockcnt;
285 /* Calculate the address of the first meta-block. */
287 metalbn = -(realbn - bn + NIADDR - i);
289 metalbn = -(-realbn - bn + NIADDR - i);
292 * At each iteration, off is the offset into the bap array which is
293 * an array of disk addresses at the current level of indirection.
294 * The logical block number and the offset in that block are stored
295 * into the argument array.
297 ap->in_lbn = metalbn;
298 ap->in_off = off = NIADDR - i;
301 for (++numlevels; i <= NIADDR; i++) {
302 /* If searching for a meta-data block, quit when found. */
303 if (metalbn == realbn)
306 off = (bn / blockcnt) % MNINDIR(ump);
309 ap->in_lbn = metalbn;
314 metalbn -= -1 + off * blockcnt;
315 blockcnt /= MNINDIR(ump);