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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>
60 * Bmap converts the logical block number of a file to its physical block
61 * number on the disk. The conversion is done by using the logical block
62 * number to index into the array of block pointers described by the dinode.
66 struct vop_bmap_args /* {
69 struct bufobj **a_bop;
79 * Check for underlying vnode requests and ensure that logical
80 * to physical mapping is requested.
82 if (ap->a_bop != NULL)
83 *ap->a_bop = &VFSTOUFS(ap->a_vp->v_mount)->um_devvp->v_bufobj;
84 if (ap->a_bnp == NULL)
87 error = ufs_bmaparray(ap->a_vp, ap->a_bn, &blkno, NULL,
88 ap->a_runp, ap->a_runb);
94 * Indirect blocks are now on the vnode for the file. They are given negative
95 * logical block numbers. Indirect blocks are addressed by the negative
96 * address of the first data block to which they point. Double indirect blocks
97 * are addressed by one less than the address of the first indirect block to
98 * which they point. Triple indirect blocks are addressed by one less than
99 * the address of the first double indirect block to which they point.
101 * ufs_bmaparray does the bmap conversion, and if requested returns the
102 * array of logical blocks which must be traversed to get to a block.
103 * Each entry contains the offset into that block that gets you to the
104 * next block and the disk address of the block (if it is assigned).
108 ufs_bmaparray(vp, bn, bnp, nbp, runp, runb)
118 struct ufsmount *ump;
120 struct indir a[UFS_NIADDR+1], *ap;
123 int error, num, maxrun = 0;
132 maxrun = mp->mnt_iosize_max / mp->mnt_stat.f_iosize - 1;
143 error = ufs_getlbns(vp, bn, ap, nump);
149 if (bn >= 0 && bn < UFS_NDADDR) {
150 *bnp = blkptrtodb(ump, DIP(ip, i_db[bn]));
151 } else if (bn < 0 && bn >= -UFS_NXADDR) {
152 *bnp = blkptrtodb(ump, ip->i_din2->di_extb[-1 - bn]);
156 panic("ufs_bmaparray: mapping ext data");
157 nbp->b_xflags |= BX_ALTDATA;
160 panic("ufs_bmaparray: blkno out of range");
163 * Since this is FFS independent code, we are out of
164 * scope for the definitions of BLK_NOCOPY and
165 * BLK_SNAP, but we do know that they will fall in
166 * the range 1..um_seqinc, so we use that test and
167 * return a request for a zeroed out buffer if attempts
168 * are made to read a BLK_NOCOPY or BLK_SNAP block.
170 if ((ip->i_flags & SF_SNAPSHOT) && DIP(ip, i_db[bn]) > 0 &&
171 DIP(ip, i_db[bn]) < ump->um_seqinc) {
173 } else if (*bnp == 0) {
174 if (ip->i_flags & SF_SNAPSHOT)
175 *bnp = blkptrtodb(ump, bn * ump->um_seqinc);
179 ufs2_daddr_t bnb = bn;
180 for (++bn; bn < UFS_NDADDR && *runp < maxrun &&
181 is_sequential(ump, DIP(ip, i_db[bn - 1]),
185 if (runb && (bn > 0)) {
186 for (--bn; (bn >= 0) && (*runb < maxrun) &&
187 is_sequential(ump, DIP(ip, i_db[bn]),
188 DIP(ip, i_db[bn+1]));
196 /* Get disk address out of indirect block array */
197 daddr = DIP(ip, i_ib[ap->in_off]);
199 for (bp = NULL, ++ap; --num; ++ap) {
201 * Exit the loop if there is no disk address assigned yet and
202 * the indirect block isn't in the cache, or if we were
203 * looking for an indirect block and we've found it.
206 metalbn = ap->in_lbn;
207 if ((daddr == 0 && !incore(&vp->v_bufobj, metalbn)) || metalbn == bn)
210 * If we get here, we've either got the block in the cache
211 * or we have a disk address for it, go fetch it.
216 bp = getblk(vp, metalbn, mp->mnt_stat.f_iosize, 0, 0, 0);
217 if ((bp->b_flags & B_CACHE) == 0) {
220 panic("ufs_bmaparray: indirect block not in cache");
222 bp->b_blkno = blkptrtodb(ump, daddr);
223 bp->b_iocmd = BIO_READ;
224 bp->b_flags &= ~B_INVAL;
225 bp->b_ioflags &= ~BIO_ERROR;
226 vfs_busy_pages(bp, 0);
227 bp->b_iooffset = dbtob(bp->b_blkno);
232 racct_add_buf(curproc, bp, 0);
233 PROC_UNLOCK(curproc);
236 curthread->td_ru.ru_inblock++;
245 daddr = ((ufs1_daddr_t *)bp->b_data)[ap->in_off];
246 if (num == 1 && daddr && runp) {
247 for (bn = ap->in_off + 1;
248 bn < MNINDIR(ump) && *runp < maxrun &&
250 ((ufs1_daddr_t *)bp->b_data)[bn - 1],
251 ((ufs1_daddr_t *)bp->b_data)[bn]);
255 for (--bn; bn >= 0 && *runb < maxrun &&
257 ((ufs1_daddr_t *)bp->b_data)[bn],
258 ((ufs1_daddr_t *)bp->b_data)[bn+1]);
264 daddr = ((ufs2_daddr_t *)bp->b_data)[ap->in_off];
265 if (num == 1 && daddr && runp) {
266 for (bn = ap->in_off + 1;
267 bn < MNINDIR(ump) && *runp < maxrun &&
269 ((ufs2_daddr_t *)bp->b_data)[bn - 1],
270 ((ufs2_daddr_t *)bp->b_data)[bn]);
274 for (--bn; bn >= 0 && *runb < maxrun &&
276 ((ufs2_daddr_t *)bp->b_data)[bn],
277 ((ufs2_daddr_t *)bp->b_data)[bn + 1]);
286 * Since this is FFS independent code, we are out of scope for the
287 * definitions of BLK_NOCOPY and BLK_SNAP, but we do know that they
288 * will fall in the range 1..um_seqinc, so we use that test and
289 * return a request for a zeroed out buffer if attempts are made
290 * to read a BLK_NOCOPY or BLK_SNAP block.
292 if ((ip->i_flags & SF_SNAPSHOT) && daddr > 0 && daddr < ump->um_seqinc){
296 *bnp = blkptrtodb(ump, daddr);
298 if (ip->i_flags & SF_SNAPSHOT)
299 *bnp = blkptrtodb(ump, bn * ump->um_seqinc);
307 * Create an array of logical block number/offset pairs which represent the
308 * path of indirect blocks required to access a data block. The first "pair"
309 * contains the logical block number of the appropriate single, double or
310 * triple indirect block and the offset into the inode indirect block array.
311 * Note, the logical block number of the inode single/double/triple indirect
312 * block appears twice in the array, once with the offset into the i_ib and
313 * once with the offset into the page itself.
316 ufs_getlbns(vp, bn, ap, nump)
322 ufs2_daddr_t blockcnt;
323 ufs_lbn_t metalbn, realbn;
324 struct ufsmount *ump;
325 int i, numlevels, off;
327 ump = VFSTOUFS(vp->v_mount);
335 /* The first UFS_NDADDR blocks are direct blocks. */
340 * Determine the number of levels of indirection. After this loop
341 * is done, blockcnt indicates the number of data blocks possible
342 * at the previous level of indirection, and UFS_NIADDR - i is the
343 * number of levels of indirection needed to locate the requested block.
345 for (blockcnt = 1, i = UFS_NIADDR, bn -= UFS_NDADDR; ;
346 i--, bn -= blockcnt) {
349 blockcnt *= MNINDIR(ump);
354 /* Calculate the address of the first meta-block. */
356 metalbn = -(realbn - bn + UFS_NIADDR - i);
358 metalbn = -(-realbn - bn + UFS_NIADDR - i);
361 * At each iteration, off is the offset into the bap array which is
362 * an array of disk addresses at the current level of indirection.
363 * The logical block number and the offset in that block are stored
364 * into the argument array.
366 ap->in_lbn = metalbn;
367 ap->in_off = off = UFS_NIADDR - i;
369 for (++numlevels; i <= UFS_NIADDR; i++) {
370 /* If searching for a meta-data block, quit when found. */
371 if (metalbn == realbn)
374 blockcnt /= MNINDIR(ump);
375 off = (bn / blockcnt) % MNINDIR(ump);
378 ap->in_lbn = metalbn;
382 metalbn -= -1 + off * blockcnt;