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34 * @(#)ufs_bmap.c 8.7 (Berkeley) 3/21/95
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
40 #include <sys/param.h>
41 #include <sys/systm.h>
45 #include <sys/vnode.h>
46 #include <sys/mount.h>
47 #include <sys/racct.h>
48 #include <sys/resourcevar.h>
51 #include <ufs/ufs/extattr.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 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 /* {
67 struct bufobj **a_bop;
77 * Check for underlying vnode requests and ensure that logical
78 * to physical mapping is requested.
80 if (ap->a_bop != NULL)
81 *ap->a_bop = &VTOI(ap->a_vp)->i_devvp->v_bufobj;
82 if (ap->a_bnp == NULL)
85 error = ufs_bmaparray(ap->a_vp, ap->a_bn, &blkno, NULL,
86 ap->a_runp, ap->a_runb);
92 * Indirect blocks are now on the vnode for the file. They are given negative
93 * logical block numbers. Indirect blocks are addressed by the negative
94 * address of the first data block to which they point. Double indirect blocks
95 * are addressed by one less than the address of the first indirect block to
96 * which they point. Triple indirect blocks are addressed by one less than
97 * the address of the first double indirect block to which they point.
99 * ufs_bmaparray does the bmap conversion, and if requested returns the
100 * array of logical blocks which must be traversed to get to a block.
101 * Each entry contains the offset into that block that gets you to the
102 * next block and the disk address of the block (if it is assigned).
106 ufs_bmaparray(vp, bn, bnp, nbp, runp, runb)
116 struct ufsmount *ump;
118 struct indir a[NIADDR+1], *ap;
121 int error, num, maxrun = 0;
130 maxrun = mp->mnt_iosize_max / mp->mnt_stat.f_iosize - 1;
141 error = ufs_getlbns(vp, bn, ap, nump);
147 if (bn >= 0 && bn < NDADDR) {
148 *bnp = blkptrtodb(ump, DIP(ip, i_db[bn]));
149 } else if (bn < 0 && bn >= -NXADDR) {
150 *bnp = blkptrtodb(ump, ip->i_din2->di_extb[-1 - bn]);
154 panic("ufs_bmaparray: mapping ext data");
155 nbp->b_xflags |= BX_ALTDATA;
158 panic("ufs_bmaparray: blkno out of range");
161 * Since this is FFS independent code, we are out of
162 * scope for the definitions of BLK_NOCOPY and
163 * BLK_SNAP, but we do know that they will fall in
164 * the range 1..um_seqinc, so we use that test and
165 * return a request for a zeroed out buffer if attempts
166 * are made to read a BLK_NOCOPY or BLK_SNAP block.
168 if ((ip->i_flags & SF_SNAPSHOT) && DIP(ip, i_db[bn]) > 0 &&
169 DIP(ip, i_db[bn]) < ump->um_seqinc) {
171 } else if (*bnp == 0) {
172 if (ip->i_flags & SF_SNAPSHOT)
173 *bnp = blkptrtodb(ump, bn * ump->um_seqinc);
177 ufs2_daddr_t bnb = bn;
178 for (++bn; bn < NDADDR && *runp < maxrun &&
179 is_sequential(ump, DIP(ip, i_db[bn - 1]),
183 if (runb && (bn > 0)) {
184 for (--bn; (bn >= 0) && (*runb < maxrun) &&
185 is_sequential(ump, DIP(ip, i_db[bn]),
186 DIP(ip, i_db[bn+1]));
194 /* Get disk address out of indirect block array */
195 daddr = DIP(ip, i_ib[ap->in_off]);
197 for (bp = NULL, ++ap; --num; ++ap) {
199 * Exit the loop if there is no disk address assigned yet and
200 * the indirect block isn't in the cache, or if we were
201 * looking for an indirect block and we've found it.
204 metalbn = ap->in_lbn;
205 if ((daddr == 0 && !incore(&vp->v_bufobj, metalbn)) || metalbn == bn)
208 * If we get here, we've either got the block in the cache
209 * or we have a disk address for it, go fetch it.
214 bp = getblk(vp, metalbn, mp->mnt_stat.f_iosize, 0, 0, 0);
215 if ((bp->b_flags & B_CACHE) == 0) {
218 panic("ufs_bmaparray: indirect block not in cache");
220 bp->b_blkno = blkptrtodb(ump, daddr);
221 bp->b_iocmd = BIO_READ;
222 bp->b_flags &= ~B_INVAL;
223 bp->b_ioflags &= ~BIO_ERROR;
224 vfs_busy_pages(bp, 0);
225 bp->b_iooffset = dbtob(bp->b_blkno);
230 racct_add_buf(curproc, bp, 0);
231 PROC_UNLOCK(curproc);
234 curthread->td_ru.ru_inblock++;
242 if (ip->i_ump->um_fstype == UFS1) {
243 daddr = ((ufs1_daddr_t *)bp->b_data)[ap->in_off];
244 if (num == 1 && daddr && runp) {
245 for (bn = ap->in_off + 1;
246 bn < MNINDIR(ump) && *runp < maxrun &&
248 ((ufs1_daddr_t *)bp->b_data)[bn - 1],
249 ((ufs1_daddr_t *)bp->b_data)[bn]);
253 for (--bn; bn >= 0 && *runb < maxrun &&
255 ((ufs1_daddr_t *)bp->b_data)[bn],
256 ((ufs1_daddr_t *)bp->b_data)[bn+1]);
262 daddr = ((ufs2_daddr_t *)bp->b_data)[ap->in_off];
263 if (num == 1 && daddr && runp) {
264 for (bn = ap->in_off + 1;
265 bn < MNINDIR(ump) && *runp < maxrun &&
267 ((ufs2_daddr_t *)bp->b_data)[bn - 1],
268 ((ufs2_daddr_t *)bp->b_data)[bn]);
272 for (--bn; bn >= 0 && *runb < maxrun &&
274 ((ufs2_daddr_t *)bp->b_data)[bn],
275 ((ufs2_daddr_t *)bp->b_data)[bn + 1]);
284 * Since this is FFS independent code, we are out of scope for the
285 * definitions of BLK_NOCOPY and BLK_SNAP, but we do know that they
286 * will fall in the range 1..um_seqinc, so we use that test and
287 * return a request for a zeroed out buffer if attempts are made
288 * to read a BLK_NOCOPY or BLK_SNAP block.
290 if ((ip->i_flags & SF_SNAPSHOT) && daddr > 0 && daddr < ump->um_seqinc){
294 *bnp = blkptrtodb(ump, daddr);
296 if (ip->i_flags & SF_SNAPSHOT)
297 *bnp = blkptrtodb(ump, bn * ump->um_seqinc);
305 * Create an array of logical block number/offset pairs which represent the
306 * path of indirect blocks required to access a data block. The first "pair"
307 * contains the logical block number of the appropriate single, double or
308 * triple indirect block and the offset into the inode indirect block array.
309 * Note, the logical block number of the inode single/double/triple indirect
310 * block appears twice in the array, once with the offset into the i_ib and
311 * once with the offset into the page itself.
314 ufs_getlbns(vp, bn, ap, nump)
320 ufs2_daddr_t blockcnt;
321 ufs_lbn_t metalbn, realbn;
322 struct ufsmount *ump;
323 int i, numlevels, off;
325 ump = VFSTOUFS(vp->v_mount);
333 /* The first NDADDR blocks are direct blocks. */
338 * Determine the number of levels of indirection. After this loop
339 * is done, blockcnt indicates the number of data blocks possible
340 * at the previous level of indirection, and NIADDR - i is the number
341 * of levels of indirection needed to locate the requested block.
343 for (blockcnt = 1, i = NIADDR, bn -= NDADDR;; i--, bn -= blockcnt) {
346 blockcnt *= MNINDIR(ump);
351 /* Calculate the address of the first meta-block. */
353 metalbn = -(realbn - bn + NIADDR - i);
355 metalbn = -(-realbn - bn + NIADDR - i);
358 * At each iteration, off is the offset into the bap array which is
359 * an array of disk addresses at the current level of indirection.
360 * The logical block number and the offset in that block are stored
361 * into the argument array.
363 ap->in_lbn = metalbn;
364 ap->in_off = off = NIADDR - i;
366 for (++numlevels; i <= NIADDR; i++) {
367 /* If searching for a meta-data block, quit when found. */
368 if (metalbn == realbn)
371 blockcnt /= MNINDIR(ump);
372 off = (bn / blockcnt) % MNINDIR(ump);
375 ap->in_lbn = metalbn;
379 metalbn -= -1 + off * blockcnt;