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36 * @(#)ufs_bmap.c 8.7 (Berkeley) 3/21/95
39 #include <sys/cdefs.h>
40 __FBSDID("$FreeBSD$");
42 #include <sys/param.h>
43 #include <sys/systm.h>
47 #include <sys/vnode.h>
48 #include <sys/mount.h>
49 #include <sys/racct.h>
50 #include <sys/resourcevar.h>
53 #include <ufs/ufs/extattr.h>
54 #include <ufs/ufs/quota.h>
55 #include <ufs/ufs/inode.h>
56 #include <ufs/ufs/ufsmount.h>
57 #include <ufs/ufs/ufs_extern.h>
59 static ufs_lbn_t lbn_count(struct ufsmount *, int);
60 static int readindir(struct vnode *, ufs_lbn_t, ufs2_daddr_t, struct buf **);
63 * Bmap converts the logical block number of a file to its physical block
64 * number on the disk. The conversion is done by using the logical block
65 * number to index into the array of block pointers described by the dinode.
69 struct vop_bmap_args /* {
72 struct bufobj **a_bop;
82 * Check for underlying vnode requests and ensure that logical
83 * to physical mapping is requested.
85 if (ap->a_bop != NULL)
86 *ap->a_bop = &VFSTOUFS(ap->a_vp->v_mount)->um_devvp->v_bufobj;
87 if (ap->a_bnp == NULL)
90 error = ufs_bmaparray(ap->a_vp, ap->a_bn, &blkno, NULL,
91 ap->a_runp, ap->a_runb);
97 readindir(vp, lbn, daddr, bpp)
105 struct ufsmount *ump;
111 bp = getblk(vp, lbn, mp->mnt_stat.f_iosize, 0, 0, 0);
112 if ((bp->b_flags & B_CACHE) == 0) {
114 ("readindir: indirect block not in cache"));
116 bp->b_blkno = blkptrtodb(ump, daddr);
117 bp->b_iocmd = BIO_READ;
118 bp->b_flags &= ~B_INVAL;
119 bp->b_ioflags &= ~BIO_ERROR;
120 vfs_busy_pages(bp, 0);
121 bp->b_iooffset = dbtob(bp->b_blkno);
126 racct_add_buf(curproc, bp, 0);
127 PROC_UNLOCK(curproc);
130 curthread->td_ru.ru_inblock++;
142 * Indirect blocks are now on the vnode for the file. They are given negative
143 * logical block numbers. Indirect blocks are addressed by the negative
144 * address of the first data block to which they point. Double indirect blocks
145 * are addressed by one less than the address of the first indirect block to
146 * which they point. Triple indirect blocks are addressed by one less than
147 * the address of the first double indirect block to which they point.
149 * ufs_bmaparray does the bmap conversion, and if requested returns the
150 * array of logical blocks which must be traversed to get to a block.
151 * Each entry contains the offset into that block that gets you to the
152 * next block and the disk address of the block (if it is assigned).
156 ufs_bmaparray(vp, bn, bnp, nbp, runp, runb)
166 struct ufsmount *ump;
168 struct indir a[UFS_NIADDR+1], *ap;
171 int error, num, maxrun = 0;
180 maxrun = mp->mnt_iosize_max / mp->mnt_stat.f_iosize - 1;
190 error = ufs_getlbns(vp, bn, ap, nump);
196 if (bn >= 0 && bn < UFS_NDADDR) {
197 *bnp = blkptrtodb(ump, DIP(ip, i_db[bn]));
198 } else if (bn < 0 && bn >= -UFS_NXADDR) {
199 *bnp = blkptrtodb(ump, ip->i_din2->di_extb[-1 - bn]);
203 /* indirect block not found */
206 nbp->b_xflags |= BX_ALTDATA;
209 /* blkno out of range */
213 * Since this is FFS independent code, we are out of
214 * scope for the definitions of BLK_NOCOPY and
215 * BLK_SNAP, but we do know that they will fall in
216 * the range 1..um_seqinc, so we use that test and
217 * return a request for a zeroed out buffer if attempts
218 * are made to read a BLK_NOCOPY or BLK_SNAP block.
220 if ((ip->i_flags & SF_SNAPSHOT) && DIP(ip, i_db[bn]) > 0 &&
221 DIP(ip, i_db[bn]) < ump->um_seqinc) {
223 } else if (*bnp == 0) {
224 if (ip->i_flags & SF_SNAPSHOT)
225 *bnp = blkptrtodb(ump, bn * ump->um_seqinc);
229 ufs2_daddr_t bnb = bn;
230 for (++bn; bn < UFS_NDADDR && *runp < maxrun &&
231 is_sequential(ump, DIP(ip, i_db[bn - 1]),
235 if (runb && (bn > 0)) {
236 for (--bn; (bn >= 0) && (*runb < maxrun) &&
237 is_sequential(ump, DIP(ip, i_db[bn]),
238 DIP(ip, i_db[bn+1]));
245 /* Get disk address out of indirect block array */
246 daddr = DIP(ip, i_ib[ap->in_off]);
248 for (bp = NULL, ++ap; --num; ++ap) {
250 * Exit the loop if there is no disk address assigned yet and
251 * the indirect block isn't in the cache, or if we were
252 * looking for an indirect block and we've found it.
255 metalbn = ap->in_lbn;
256 if ((daddr == 0 && !incore(&vp->v_bufobj, metalbn)) || metalbn == bn)
259 * If we get here, we've either got the block in the cache
260 * or we have a disk address for it, go fetch it.
264 error = readindir(vp, metalbn, daddr, &bp);
269 daddr = ((ufs1_daddr_t *)bp->b_data)[ap->in_off];
271 daddr = ((ufs2_daddr_t *)bp->b_data)[ap->in_off];
272 if ((error = UFS_CHECK_BLKNO(mp, ip->i_number, daddr,
273 mp->mnt_stat.f_iosize)) != 0) {
278 if (num == 1 && daddr && runp) {
279 for (bn = ap->in_off + 1;
280 bn < MNINDIR(ump) && *runp < maxrun &&
282 ((ufs1_daddr_t *)bp->b_data)[bn - 1],
283 ((ufs1_daddr_t *)bp->b_data)[bn]);
287 for (--bn; bn >= 0 && *runb < maxrun &&
289 ((ufs1_daddr_t *)bp->b_data)[bn],
290 ((ufs1_daddr_t *)bp->b_data)[bn+1]);
296 if (num == 1 && daddr && runp) {
297 for (bn = ap->in_off + 1;
298 bn < MNINDIR(ump) && *runp < maxrun &&
300 ((ufs2_daddr_t *)bp->b_data)[bn - 1],
301 ((ufs2_daddr_t *)bp->b_data)[bn]);
305 for (--bn; bn >= 0 && *runb < maxrun &&
307 ((ufs2_daddr_t *)bp->b_data)[bn],
308 ((ufs2_daddr_t *)bp->b_data)[bn + 1]);
317 * Since this is FFS independent code, we are out of scope for the
318 * definitions of BLK_NOCOPY and BLK_SNAP, but we do know that they
319 * will fall in the range 1..um_seqinc, so we use that test and
320 * return a request for a zeroed out buffer if attempts are made
321 * to read a BLK_NOCOPY or BLK_SNAP block.
323 if ((ip->i_flags & SF_SNAPSHOT) && daddr > 0 && daddr < ump->um_seqinc){
327 *bnp = blkptrtodb(ump, daddr);
329 if (ip->i_flags & SF_SNAPSHOT)
330 *bnp = blkptrtodb(ump, bn * ump->um_seqinc);
338 lbn_count(ump, level)
339 struct ufsmount *ump;
344 for (blockcnt = 1; level > 0; level--)
345 blockcnt *= MNINDIR(ump);
350 ufs_bmap_seekdata(vp, offp)
355 struct indir a[UFS_NIADDR + 1], *ap;
358 struct ufsmount *ump;
359 ufs2_daddr_t bn, daddr, nextbn;
362 int error, num, num1, off;
370 if (vp->v_type != VREG || (ip->i_flags & SF_SNAPSHOT) != 0)
372 if (*offp < 0 || *offp >= ip->i_size)
375 bsize = mp->mnt_stat.f_iosize;
376 for (bn = *offp / bsize, numblks = howmany(ip->i_size, bsize);
377 bn < numblks; bn = nextbn) {
378 if (bn < UFS_NDADDR) {
379 daddr = DIP(ip, i_db[bn]);
387 error = ufs_getlbns(vp, bn, ap, &num);
391 daddr = DIP(ip, i_ib[ap->in_off]);
393 for (nextbn = UFS_NDADDR, num1 = num - 1; num1 > 0; num1--)
394 nextbn += lbn_count(ump, num1);
396 nextbn += lbn_count(ump, num);
400 for (; daddr != 0 && num > 0; ap++, num--) {
403 error = readindir(vp, ap->in_lbn, daddr, &bp);
408 * Scan the indirect block until we find a non-zero
413 daddr = I_IS_UFS1(ip) ?
414 ((ufs1_daddr_t *)bp->b_data)[off] :
415 ((ufs2_daddr_t *)bp->b_data)[off];
416 } while (daddr == 0 && ++off < MNINDIR(ump));
417 nextbn += off * lbn_count(ump, num - 1);
420 * We need to recompute the LBNs of indirect
421 * blocks, so restart with the updated block offset.
423 if (off != ap->in_off)
428 * We found a data block.
438 if (error == 0 && *offp < bn * bsize)
444 * Create an array of logical block number/offset pairs which represent the
445 * path of indirect blocks required to access a data block. The first "pair"
446 * contains the logical block number of the appropriate single, double or
447 * triple indirect block and the offset into the inode indirect block array.
448 * Note, the logical block number of the inode single/double/triple indirect
449 * block appears twice in the array, once with the offset into the i_ib and
450 * once with the offset into the page itself.
453 ufs_getlbns(vp, bn, ap, nump)
459 ufs2_daddr_t blockcnt;
460 ufs_lbn_t metalbn, realbn;
461 struct ufsmount *ump;
462 int i, numlevels, off;
464 ump = VFSTOUFS(vp->v_mount);
472 /* The first UFS_NDADDR blocks are direct blocks. */
477 * Determine the number of levels of indirection. After this loop
478 * is done, blockcnt indicates the number of data blocks possible
479 * at the previous level of indirection, and UFS_NIADDR - i is the
480 * number of levels of indirection needed to locate the requested block.
482 for (blockcnt = 1, i = UFS_NIADDR, bn -= UFS_NDADDR; ;
483 i--, bn -= blockcnt) {
486 blockcnt *= MNINDIR(ump);
491 /* Calculate the address of the first meta-block. */
493 metalbn = -(realbn - bn + UFS_NIADDR - i);
495 metalbn = -(-realbn - bn + UFS_NIADDR - i);
498 * At each iteration, off is the offset into the bap array which is
499 * an array of disk addresses at the current level of indirection.
500 * The logical block number and the offset in that block are stored
501 * into the argument array.
503 ap->in_lbn = metalbn;
504 ap->in_off = off = UFS_NIADDR - i;
506 for (++numlevels; i <= UFS_NIADDR; i++) {
507 /* If searching for a meta-data block, quit when found. */
508 if (metalbn == realbn)
511 blockcnt /= MNINDIR(ump);
512 off = (bn / blockcnt) % MNINDIR(ump);
515 ap->in_lbn = metalbn;
519 metalbn -= -1 + off * blockcnt;