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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/rwlock.h>
48 #include <sys/vnode.h>
49 #include <sys/mount.h>
50 #include <sys/racct.h>
51 #include <sys/resourcevar.h>
55 #include <vm/vm_object.h>
57 #include <ufs/ufs/extattr.h>
58 #include <ufs/ufs/quota.h>
59 #include <ufs/ufs/inode.h>
60 #include <ufs/ufs/ufsmount.h>
61 #include <ufs/ufs/ufs_extern.h>
63 static ufs_lbn_t lbn_count(struct ufsmount *, int);
64 static int readindir(struct vnode *, ufs_lbn_t, ufs2_daddr_t, struct buf **);
67 * Bmap converts the logical block number of a file to its physical block
68 * number on the disk. The conversion is done by using the logical block
69 * number to index into the array of block pointers described by the dinode.
73 struct vop_bmap_args /* {
76 struct bufobj **a_bop;
86 * Check for underlying vnode requests and ensure that logical
87 * to physical mapping is requested.
89 if (ap->a_bop != NULL)
90 *ap->a_bop = &VFSTOUFS(ap->a_vp->v_mount)->um_devvp->v_bufobj;
91 if (ap->a_bnp == NULL)
94 error = ufs_bmaparray(ap->a_vp, ap->a_bn, &blkno, NULL,
95 ap->a_runp, ap->a_runb);
101 readindir(struct vnode *vp,
108 struct ufsmount *ump;
114 bp = getblk(vp, lbn, mp->mnt_stat.f_iosize, 0, 0, 0);
115 if ((bp->b_flags & B_CACHE) == 0) {
117 ("readindir: indirect block not in cache"));
119 bp->b_blkno = blkptrtodb(ump, daddr);
120 bp->b_iocmd = BIO_READ;
121 bp->b_flags &= ~B_INVAL;
122 bp->b_ioflags &= ~BIO_ERROR;
123 vfs_busy_pages(bp, 0);
124 bp->b_iooffset = dbtob(bp->b_blkno);
129 racct_add_buf(curproc, bp, 0);
130 PROC_UNLOCK(curproc);
133 curthread->td_ru.ru_inblock++;
145 * Indirect blocks are now on the vnode for the file. They are given negative
146 * logical block numbers. Indirect blocks are addressed by the negative
147 * address of the first data block to which they point. Double indirect blocks
148 * are addressed by one less than the address of the first indirect block to
149 * which they point. Triple indirect blocks are addressed by one less than
150 * the address of the first double indirect block to which they point.
152 * ufs_bmaparray does the bmap conversion, and if requested returns the
153 * array of logical blocks which must be traversed to get to a block.
154 * Each entry contains the offset into that block that gets you to the
155 * next block and the disk address of the block (if it is assigned).
159 ufs_bmaparray(struct vnode *vp,
168 struct ufsmount *ump;
170 struct indir a[UFS_NIADDR+1], *ap;
173 int error, num, maxrun = 0;
182 maxrun = mp->mnt_iosize_max / mp->mnt_stat.f_iosize - 1;
192 error = ufs_getlbns(vp, bn, ap, nump);
198 if (bn >= 0 && bn < UFS_NDADDR) {
199 *bnp = blkptrtodb(ump, DIP(ip, i_db[bn]));
200 } else if (bn < 0 && bn >= -UFS_NXADDR) {
201 *bnp = blkptrtodb(ump, ip->i_din2->di_extb[-1 - bn]);
205 /* indirect block not found */
208 nbp->b_xflags |= BX_ALTDATA;
211 /* blkno out of range */
215 * Since this is FFS independent code, we are out of
216 * scope for the definitions of BLK_NOCOPY and
217 * BLK_SNAP, but we do know that they will fall in
218 * the range 1..um_seqinc, so we use that test and
219 * return a request for a zeroed out buffer if attempts
220 * are made to read a BLK_NOCOPY or BLK_SNAP block.
222 if (IS_SNAPSHOT(ip) && DIP(ip, i_db[bn]) > 0 &&
223 DIP(ip, i_db[bn]) < ump->um_seqinc) {
225 } else if (*bnp == 0) {
226 *bnp = IS_SNAPSHOT(ip) ? blkptrtodb(ump,
227 bn * ump->um_seqinc) : -1;
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 (IS_SNAPSHOT(ip) && daddr > 0 && daddr < ump->um_seqinc){
327 *bnp = blkptrtodb(ump, daddr);
330 *bnp = blkptrtodb(ump, bn * ump->um_seqinc);
338 lbn_count(struct ufsmount *ump, int level)
342 for (blockcnt = 1; level > 0; level--)
343 blockcnt *= MNINDIR(ump);
348 ufs_bmap_seekdata(struct vnode *vp, off_t *offp)
351 struct indir a[UFS_NIADDR + 1], *ap;
354 struct ufsmount *ump;
356 ufs2_daddr_t bn, daddr, nextbn;
359 int error, num, num1, off;
367 if (vp->v_type != VREG || IS_SNAPSHOT(ip))
369 if (*offp < 0 || *offp >= ip->i_size)
373 * We could have pages on the vnode' object queue which still
374 * do not have the data blocks allocated. Convert all dirty
375 * pages into buffer writes to ensure that we see all
380 VM_OBJECT_WLOCK(obj);
381 vm_object_page_clean(obj, 0, 0, OBJPC_SYNC);
382 VM_OBJECT_WUNLOCK(obj);
385 bsize = mp->mnt_stat.f_iosize;
386 for (bn = *offp / bsize, numblks = howmany(ip->i_size, bsize);
387 bn < numblks; bn = nextbn) {
388 if (bn < UFS_NDADDR) {
389 daddr = DIP(ip, i_db[bn]);
397 error = ufs_getlbns(vp, bn, ap, &num);
401 daddr = DIP(ip, i_ib[ap->in_off]);
403 for (nextbn = UFS_NDADDR, num1 = num - 1; num1 > 0; num1--)
404 nextbn += lbn_count(ump, num1);
406 nextbn += lbn_count(ump, num);
410 for (; daddr != 0 && num > 0; ap++, num--) {
413 error = readindir(vp, ap->in_lbn, daddr, &bp);
418 * Scan the indirect block until we find a non-zero
423 daddr = I_IS_UFS1(ip) ?
424 ((ufs1_daddr_t *)bp->b_data)[off] :
425 ((ufs2_daddr_t *)bp->b_data)[off];
426 } while (daddr == 0 && ++off < MNINDIR(ump));
427 nextbn += off * lbn_count(ump, num - 1);
430 * We need to recompute the LBNs of indirect
431 * blocks, so restart with the updated block offset.
433 if (off != ap->in_off)
438 * We found a data block.
448 if (error == 0 && *offp < bn * bsize)
454 * Create an array of logical block number/offset pairs which represent the
455 * path of indirect blocks required to access a data block. The first "pair"
456 * contains the logical block number of the appropriate single, double or
457 * triple indirect block and the offset into the inode indirect block array.
458 * Note, the logical block number of the inode single/double/triple indirect
459 * block appears twice in the array, once with the offset into the i_ib and
460 * once with the offset into the page itself.
463 ufs_getlbns(struct vnode *vp,
468 ufs2_daddr_t blockcnt;
469 ufs_lbn_t metalbn, realbn;
470 struct ufsmount *ump;
471 int i, numlevels, off;
473 ump = VFSTOUFS(vp->v_mount);
481 /* The first UFS_NDADDR blocks are direct blocks. */
486 * Determine the number of levels of indirection. After this loop
487 * is done, blockcnt indicates the number of data blocks possible
488 * at the previous level of indirection, and UFS_NIADDR - i is the
489 * number of levels of indirection needed to locate the requested block.
491 for (blockcnt = 1, i = UFS_NIADDR, bn -= UFS_NDADDR; ;
492 i--, bn -= blockcnt) {
495 blockcnt *= MNINDIR(ump);
500 /* Calculate the address of the first meta-block. */
502 metalbn = -(realbn - bn + UFS_NIADDR - i);
504 metalbn = -(-realbn - bn + UFS_NIADDR - i);
507 * At each iteration, off is the offset into the bap array which is
508 * an array of disk addresses at the current level of indirection.
509 * The logical block number and the offset in that block are stored
510 * into the argument array.
512 ap->in_lbn = metalbn;
513 ap->in_off = off = UFS_NIADDR - i;
515 for (++numlevels; i <= UFS_NIADDR; i++) {
516 /* If searching for a meta-data block, quit when found. */
517 if (metalbn == realbn)
520 blockcnt /= MNINDIR(ump);
521 off = (bn / blockcnt) % MNINDIR(ump);
524 ap->in_lbn = metalbn;
528 metalbn -= -1 + off * blockcnt;