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34 * @(#)ufs_bmap.c 8.7 (Berkeley) 3/21/95
38 #include <sys/param.h>
39 #include <sys/systm.h>
43 #include <sys/vnode.h>
44 #include <sys/mount.h>
45 #include <sys/resourcevar.h>
48 #include <fs/ext2fs/inode.h>
49 #include <fs/ext2fs/fs.h>
50 #include <fs/ext2fs/ext2fs.h>
51 #include <fs/ext2fs/ext2_dinode.h>
52 #include <fs/ext2fs/ext2_extern.h>
53 #include <fs/ext2fs/ext2_mount.h>
55 static int ext4_bmapext(struct vnode *, int32_t, int64_t *, int *, int *);
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.
63 ext2_bmap(struct vop_bmap_args *ap)
69 * Check for underlying vnode requests and ensure that logical
70 * to physical mapping is requested.
72 if (ap->a_bop != NULL)
73 *ap->a_bop = &VTOI(ap->a_vp)->i_devvp->v_bufobj;
74 if (ap->a_bnp == NULL)
77 if (VTOI(ap->a_vp)->i_flag & IN_E4EXTENTS)
78 error = ext4_bmapext(ap->a_vp, ap->a_bn, &blkno,
79 ap->a_runp, ap->a_runb);
81 error = ext2_bmaparray(ap->a_vp, ap->a_bn, &blkno,
82 ap->a_runp, ap->a_runb);
88 * This function converts the logical block number of a file to
89 * its physical block number on the disk within ext4 extents.
92 ext4_bmapext(struct vnode *vp, int32_t bn, int64_t *bnp, int *runp, int *runb)
96 struct ext4_extent *ep;
97 struct ext4_extent_path path = { .ep_bp = NULL };
106 * TODO: need to implement read ahead to improve the performance.
114 ext4_ext_find_extent(fs, ip, lbn, &path);
119 *bnp = fsbtodb(fs, lbn - ep->e_blk +
120 (ep->e_start_lo | (daddr_t)ep->e_start_hi << 32));
126 if (path.ep_bp != NULL) {
135 * Indirect blocks are now on the vnode for the file. They are given negative
136 * logical block numbers. Indirect blocks are addressed by the negative
137 * address of the first data block to which they point. Double indirect blocks
138 * are addressed by one less than the address of the first indirect block to
139 * which they point. Triple indirect blocks are addressed by one less than
140 * the address of the first double indirect block to which they point.
142 * ext2_bmaparray does the bmap conversion, and if requested returns the
143 * array of logical blocks which must be traversed to get to a block.
144 * Each entry contains the offset into that block that gets you to the
145 * next block and the disk address of the block (if it is assigned).
149 ext2_bmaparray(struct vnode *vp, daddr_t bn, daddr_t *bnp, int *runp, int *runb)
153 struct ext2mount *ump;
155 struct indir a[NIADDR+1], *ap;
158 int error, num, maxrun = 0, bsize;
166 bsize = EXT2_BLOCK_SIZE(ump->um_e2fs);
169 maxrun = mp->mnt_iosize_max / bsize - 1;
180 error = ext2_getlbns(vp, bn, ap, nump);
186 *bnp = blkptrtodb(ump, ip->i_db[bn]);
191 for (++bn; bn < NDADDR && *runp < maxrun &&
192 is_sequential(ump, ip->i_db[bn - 1], ip->i_db[bn]);
195 if (runb && (bn > 0)) {
196 for (--bn; (bn >= 0) && (*runb < maxrun) &&
197 is_sequential(ump, ip->i_db[bn],
206 /* Get disk address out of indirect block array */
207 daddr = ip->i_ib[ap->in_off];
209 for (bp = NULL, ++ap; --num; ++ap) {
211 * Exit the loop if there is no disk address assigned yet and
212 * the indirect block isn't in the cache, or if we were
213 * looking for an indirect block and we've found it.
216 metalbn = ap->in_lbn;
217 if ((daddr == 0 && !incore(&vp->v_bufobj, metalbn)) || metalbn == bn)
220 * If we get here, we've either got the block in the cache
221 * or we have a disk address for it, go fetch it.
226 bp = getblk(vp, metalbn, bsize, 0, 0, 0);
227 if ((bp->b_flags & B_CACHE) == 0) {
230 panic("ext2_bmaparray: indirect block not in cache");
232 bp->b_blkno = blkptrtodb(ump, daddr);
233 bp->b_iocmd = BIO_READ;
234 bp->b_flags &= ~B_INVAL;
235 bp->b_ioflags &= ~BIO_ERROR;
236 vfs_busy_pages(bp, 0);
237 bp->b_iooffset = dbtob(bp->b_blkno);
239 curthread->td_ru.ru_inblock++;
247 daddr = ((e2fs_daddr_t *)bp->b_data)[ap->in_off];
248 if (num == 1 && daddr && runp) {
249 for (bn = ap->in_off + 1;
250 bn < MNINDIR(ump) && *runp < maxrun &&
252 ((e2fs_daddr_t *)bp->b_data)[bn - 1],
253 ((e2fs_daddr_t *)bp->b_data)[bn]);
257 for (--bn; bn >= 0 && *runb < maxrun &&
259 ((e2fs_daddr_t *)bp->b_data)[bn],
260 ((e2fs_daddr_t *)bp->b_data)[bn + 1]);
269 * Since this is FFS independent code, we are out of scope for the
270 * definitions of BLK_NOCOPY and BLK_SNAP, but we do know that they
271 * will fall in the range 1..um_seqinc, so we use that test and
272 * return a request for a zeroed out buffer if attempts are made
273 * to read a BLK_NOCOPY or BLK_SNAP block.
275 if ((ip->i_flags & SF_SNAPSHOT) && daddr > 0 && daddr < ump->um_seqinc){
279 *bnp = blkptrtodb(ump, daddr);
287 * Create an array of logical block number/offset pairs which represent the
288 * path of indirect blocks required to access a data block. The first "pair"
289 * contains the logical block number of the appropriate single, double or
290 * triple indirect block and the offset into the inode indirect block array.
291 * Note, the logical block number of the inode single/double/triple indirect
292 * block appears twice in the array, once with the offset into the i_ib and
293 * once with the offset into the page itself.
296 ext2_getlbns(struct vnode *vp, daddr_t bn, struct indir *ap, int *nump)
299 e2fs_lbn_t metalbn, realbn;
300 struct ext2mount *ump;
301 int i, numlevels, off;
304 ump = VFSTOEXT2(vp->v_mount);
312 /* The first NDADDR blocks are direct blocks. */
317 * Determine the number of levels of indirection. After this loop
318 * is done, blockcnt indicates the number of data blocks possible
319 * at the previous level of indirection, and NIADDR - i is the number
320 * of levels of indirection needed to locate the requested block.
322 for (blockcnt = 1, i = NIADDR, bn -= NDADDR;; i--, bn -= blockcnt) {
326 * Use int64_t's here to avoid overflow for triple indirect
327 * blocks when longs have 32 bits and the block size is more
330 qblockcnt = (int64_t)blockcnt * MNINDIR(ump);
333 blockcnt = qblockcnt;
336 /* Calculate the address of the first meta-block. */
338 metalbn = -(realbn - bn + NIADDR - i);
340 metalbn = -(-realbn - bn + NIADDR - i);
343 * At each iteration, off is the offset into the bap array which is
344 * an array of disk addresses at the current level of indirection.
345 * The logical block number and the offset in that block are stored
346 * into the argument array.
348 ap->in_lbn = metalbn;
349 ap->in_off = off = NIADDR - i;
351 for (++numlevels; i <= NIADDR; i++) {
352 /* If searching for a meta-data block, quit when found. */
353 if (metalbn == realbn)
356 off = (bn / blockcnt) % MNINDIR(ump);
359 ap->in_lbn = metalbn;
363 metalbn -= -1 + off * blockcnt;
364 blockcnt /= MNINDIR(ump);