1 /*-
2 * modified for Lites 1.1
3 *
4 * Aug 1995, Godmar Back (gback@cs.utah.edu)
5 * University of Utah, Department of Computer Science
6 */
7 /*-
8 * Copyright (c) 1982, 1986, 1989, 1993
9 * The Regents of the University of California. All rights reserved.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 4. Neither the name of the University nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 *
35 * @(#)ffs_alloc.c 8.8 (Berkeley) 2/21/94
36 * $FreeBSD: releng/11.1/sys/fs/ext2fs/ext2_alloc.c 311231 2017-01-04 02:42:17Z pfg $
37 */
38
39 #include <sys/param.h>
40 #include <sys/systm.h>
41 #include <sys/conf.h>
42 #include <sys/vnode.h>
43 #include <sys/stat.h>
44 #include <sys/mount.h>
45 #include <sys/sysctl.h>
46 #include <sys/syslog.h>
47 #include <sys/buf.h>
48
49 #include <fs/ext2fs/fs.h>
50 #include <fs/ext2fs/inode.h>
51 #include <fs/ext2fs/ext2_mount.h>
52 #include <fs/ext2fs/ext2fs.h>
53 #include <fs/ext2fs/ext2_extern.h>
54
55 static daddr_t ext2_alloccg(struct inode *, int, daddr_t, int);
56 static daddr_t ext2_clusteralloc(struct inode *, int, daddr_t, int);
57 static u_long ext2_dirpref(struct inode *);
58 static void ext2_fserr(struct m_ext2fs *, uid_t, char *);
59 static u_long ext2_hashalloc(struct inode *, int, long, int,
60 daddr_t (*)(struct inode *, int, daddr_t,
61 int));
62 static daddr_t ext2_nodealloccg(struct inode *, int, daddr_t, int);
63 static daddr_t ext2_mapsearch(struct m_ext2fs *, char *, daddr_t);
64
65 /*
66 * Allocate a block in the filesystem.
67 *
68 * A preference may be optionally specified. If a preference is given
69 * the following hierarchy is used to allocate a block:
70 * 1) allocate the requested block.
71 * 2) allocate a rotationally optimal block in the same cylinder.
72 * 3) allocate a block in the same cylinder group.
73 * 4) quadradically rehash into other cylinder groups, until an
74 * available block is located.
75 * If no block preference is given the following hierarchy is used
76 * to allocate a block:
77 * 1) allocate a block in the cylinder group that contains the
78 * inode for the file.
79 * 2) quadradically rehash into other cylinder groups, until an
80 * available block is located.
81 */
82 int
83 ext2_alloc(struct inode *ip, daddr_t lbn, e4fs_daddr_t bpref, int size,
84 struct ucred *cred, e4fs_daddr_t *bnp)
85 {
86 struct m_ext2fs *fs;
87 struct ext2mount *ump;
88 int32_t bno;
89 int cg;
90
91 *bnp = 0;
92 fs = ip->i_e2fs;
93 ump = ip->i_ump;
94 mtx_assert(EXT2_MTX(ump), MA_OWNED);
95 #ifdef INVARIANTS
96 if ((u_int)size > fs->e2fs_bsize || blkoff(fs, size) != 0) {
97 vn_printf(ip->i_devvp, "bsize = %lu, size = %d, fs = %s\n",
98 (long unsigned int)fs->e2fs_bsize, size, fs->e2fs_fsmnt);
99 panic("ext2_alloc: bad size");
100 }
101 if (cred == NOCRED)
102 panic("ext2_alloc: missing credential");
103 #endif /* INVARIANTS */
104 if (size == fs->e2fs_bsize && fs->e2fs->e2fs_fbcount == 0)
105 goto nospace;
106 if (cred->cr_uid != 0 &&
107 fs->e2fs->e2fs_fbcount < fs->e2fs->e2fs_rbcount)
108 goto nospace;
109 if (bpref >= fs->e2fs->e2fs_bcount)
110 bpref = 0;
111 if (bpref == 0)
112 cg = ino_to_cg(fs, ip->i_number);
113 else
114 cg = dtog(fs, bpref);
115 bno = (daddr_t)ext2_hashalloc(ip, cg, bpref, fs->e2fs_bsize,
116 ext2_alloccg);
117 if (bno > 0) {
118 /* set next_alloc fields as done in block_getblk */
119 ip->i_next_alloc_block = lbn;
120 ip->i_next_alloc_goal = bno;
121
122 ip->i_blocks += btodb(fs->e2fs_bsize);
123 ip->i_flag |= IN_CHANGE | IN_UPDATE;
124 *bnp = bno;
125 return (0);
126 }
127 nospace:
128 EXT2_UNLOCK(ump);
129 ext2_fserr(fs, cred->cr_uid, "filesystem full");
130 uprintf("\n%s: write failed, filesystem is full\n", fs->e2fs_fsmnt);
131 return (ENOSPC);
132 }
133
134 /*
135 * Reallocate a sequence of blocks into a contiguous sequence of blocks.
136 *
137 * The vnode and an array of buffer pointers for a range of sequential
138 * logical blocks to be made contiguous is given. The allocator attempts
139 * to find a range of sequential blocks starting as close as possible to
140 * an fs_rotdelay offset from the end of the allocation for the logical
141 * block immediately preceding the current range. If successful, the
142 * physical block numbers in the buffer pointers and in the inode are
143 * changed to reflect the new allocation. If unsuccessful, the allocation
144 * is left unchanged. The success in doing the reallocation is returned.
145 * Note that the error return is not reflected back to the user. Rather
146 * the previous block allocation will be used.
147 */
148
149 static SYSCTL_NODE(_vfs, OID_AUTO, ext2fs, CTLFLAG_RW, 0, "EXT2FS filesystem");
150
151 static int doasyncfree = 1;
152
153 SYSCTL_INT(_vfs_ext2fs, OID_AUTO, doasyncfree, CTLFLAG_RW, &doasyncfree, 0,
154 "Use asychronous writes to update block pointers when freeing blocks");
155
156 static int doreallocblks = 1;
157
158 SYSCTL_INT(_vfs_ext2fs, OID_AUTO, doreallocblks, CTLFLAG_RW, &doreallocblks, 0, "");
159
160 int
161 ext2_reallocblks(struct vop_reallocblks_args *ap)
162 {
163 struct m_ext2fs *fs;
164 struct inode *ip;
165 struct vnode *vp;
166 struct buf *sbp, *ebp;
167 uint32_t *bap, *sbap, *ebap;
168 struct ext2mount *ump;
169 struct cluster_save *buflist;
170 struct indir start_ap[NIADDR + 1], end_ap[NIADDR + 1], *idp;
171 e2fs_lbn_t start_lbn, end_lbn;
172 int soff;
173 e2fs_daddr_t newblk, blkno;
174 int i, len, start_lvl, end_lvl, pref, ssize;
175
176 if (doreallocblks == 0)
177 return (ENOSPC);
178
179 vp = ap->a_vp;
180 ip = VTOI(vp);
181 fs = ip->i_e2fs;
182 ump = ip->i_ump;
183
184 if (fs->e2fs_contigsumsize <= 0)
185 return (ENOSPC);
186
187 buflist = ap->a_buflist;
188 len = buflist->bs_nchildren;
189 start_lbn = buflist->bs_children[0]->b_lblkno;
190 end_lbn = start_lbn + len - 1;
191 #ifdef INVARIANTS
192 for (i = 1; i < len; i++)
193 if (buflist->bs_children[i]->b_lblkno != start_lbn + i)
194 panic("ext2_reallocblks: non-cluster");
195 #endif
196 /*
197 * If the cluster crosses the boundary for the first indirect
198 * block, leave space for the indirect block. Indirect blocks
199 * are initially laid out in a position after the last direct
200 * block. Block reallocation would usually destroy locality by
201 * moving the indirect block out of the way to make room for
202 * data blocks if we didn't compensate here. We should also do
203 * this for other indirect block boundaries, but it is only
204 * important for the first one.
205 */
206 if (start_lbn < NDADDR && end_lbn >= NDADDR)
207 return (ENOSPC);
208 /*
209 * If the latest allocation is in a new cylinder group, assume that
210 * the filesystem has decided to move and do not force it back to
211 * the previous cylinder group.
212 */
213 if (dtog(fs, dbtofsb(fs, buflist->bs_children[0]->b_blkno)) !=
214 dtog(fs, dbtofsb(fs, buflist->bs_children[len - 1]->b_blkno)))
215 return (ENOSPC);
216 if (ext2_getlbns(vp, start_lbn, start_ap, &start_lvl) ||
217 ext2_getlbns(vp, end_lbn, end_ap, &end_lvl))
218 return (ENOSPC);
219 /*
220 * Get the starting offset and block map for the first block.
221 */
222 if (start_lvl == 0) {
223 sbap = &ip->i_db[0];
224 soff = start_lbn;
225 } else {
226 idp = &start_ap[start_lvl - 1];
227 if (bread(vp, idp->in_lbn, (int)fs->e2fs_bsize, NOCRED, &sbp)) {
228 brelse(sbp);
229 return (ENOSPC);
230 }
231 sbap = (u_int *)sbp->b_data;
232 soff = idp->in_off;
233 }
234 /*
235 * If the block range spans two block maps, get the second map.
236 */
237 ebap = NULL;
238 if (end_lvl == 0 || (idp = &end_ap[end_lvl - 1])->in_off + 1 >= len) {
239 ssize = len;
240 } else {
241 #ifdef INVARIANTS
242 if (start_ap[start_lvl - 1].in_lbn == idp->in_lbn)
243 panic("ext2_reallocblks: start == end");
244 #endif
245 ssize = len - (idp->in_off + 1);
246 if (bread(vp, idp->in_lbn, (int)fs->e2fs_bsize, NOCRED, &ebp))
247 goto fail;
248 ebap = (u_int *)ebp->b_data;
249 }
250 /*
251 * Find the preferred location for the cluster.
252 */
253 EXT2_LOCK(ump);
254 pref = ext2_blkpref(ip, start_lbn, soff, sbap, 0);
255 /*
256 * Search the block map looking for an allocation of the desired size.
257 */
258 if ((newblk = (e2fs_daddr_t)ext2_hashalloc(ip, dtog(fs, pref), pref,
259 len, ext2_clusteralloc)) == 0) {
260 EXT2_UNLOCK(ump);
261 goto fail;
262 }
263 /*
264 * We have found a new contiguous block.
265 *
266 * First we have to replace the old block pointers with the new
267 * block pointers in the inode and indirect blocks associated
268 * with the file.
269 */
270 #ifdef DEBUG
271 printf("realloc: ino %ju, lbns %jd-%jd\n\told:",
272 (uintmax_t)ip->i_number, (intmax_t)start_lbn, (intmax_t)end_lbn);
273 #endif /* DEBUG */
274 blkno = newblk;
275 for (bap = &sbap[soff], i = 0; i < len; i++, blkno += fs->e2fs_fpb) {
276 if (i == ssize) {
277 bap = ebap;
278 soff = -i;
279 }
280 #ifdef INVARIANTS
281 if (buflist->bs_children[i]->b_blkno != fsbtodb(fs, *bap))
282 panic("ext2_reallocblks: alloc mismatch");
283 #endif
284 #ifdef DEBUG
285 printf(" %d,", *bap);
286 #endif /* DEBUG */
287 *bap++ = blkno;
288 }
289 /*
290 * Next we must write out the modified inode and indirect blocks.
291 * For strict correctness, the writes should be synchronous since
292 * the old block values may have been written to disk. In practise
293 * they are almost never written, but if we are concerned about
294 * strict correctness, the `doasyncfree' flag should be set to zero.
295 *
296 * The test on `doasyncfree' should be changed to test a flag
297 * that shows whether the associated buffers and inodes have
298 * been written. The flag should be set when the cluster is
299 * started and cleared whenever the buffer or inode is flushed.
300 * We can then check below to see if it is set, and do the
301 * synchronous write only when it has been cleared.
302 */
303 if (sbap != &ip->i_db[0]) {
304 if (doasyncfree)
305 bdwrite(sbp);
306 else
307 bwrite(sbp);
308 } else {
309 ip->i_flag |= IN_CHANGE | IN_UPDATE;
310 if (!doasyncfree)
311 ext2_update(vp, 1);
312 }
313 if (ssize < len) {
314 if (doasyncfree)
315 bdwrite(ebp);
316 else
317 bwrite(ebp);
318 }
319 /*
320 * Last, free the old blocks and assign the new blocks to the buffers.
321 */
322 #ifdef DEBUG
323 printf("\n\tnew:");
324 #endif /* DEBUG */
325 for (blkno = newblk, i = 0; i < len; i++, blkno += fs->e2fs_fpb) {
326 ext2_blkfree(ip, dbtofsb(fs, buflist->bs_children[i]->b_blkno),
327 fs->e2fs_bsize);
328 buflist->bs_children[i]->b_blkno = fsbtodb(fs, blkno);
329 #ifdef DEBUG
330 printf(" %d,", blkno);
331 #endif /* DEBUG */
332 }
333 #ifdef DEBUG
334 printf("\n");
335 #endif /* DEBUG */
336 return (0);
337
338 fail:
339 if (ssize < len)
340 brelse(ebp);
341 if (sbap != &ip->i_db[0])
342 brelse(sbp);
343 return (ENOSPC);
344 }
345
346 /*
347 * Allocate an inode in the filesystem.
348 *
349 */
350 int
351 ext2_valloc(struct vnode *pvp, int mode, struct ucred *cred, struct vnode **vpp)
352 {
353 struct timespec ts;
354 struct inode *pip;
355 struct m_ext2fs *fs;
356 struct inode *ip;
357 struct ext2mount *ump;
358 ino_t ino, ipref;
359 int i, error, cg;
360
361 *vpp = NULL;
362 pip = VTOI(pvp);
363 fs = pip->i_e2fs;
364 ump = pip->i_ump;
365
366 EXT2_LOCK(ump);
367 if (fs->e2fs->e2fs_ficount == 0)
368 goto noinodes;
369 /*
370 * If it is a directory then obtain a cylinder group based on
371 * ext2_dirpref else obtain it using ino_to_cg. The preferred inode is
372 * always the next inode.
373 */
374 if ((mode & IFMT) == IFDIR) {
375 cg = ext2_dirpref(pip);
376 if (fs->e2fs_contigdirs[cg] < 255)
377 fs->e2fs_contigdirs[cg]++;
378 } else {
379 cg = ino_to_cg(fs, pip->i_number);
380 if (fs->e2fs_contigdirs[cg] > 0)
381 fs->e2fs_contigdirs[cg]--;
382 }
383 ipref = cg * fs->e2fs->e2fs_ipg + 1;
384 ino = (ino_t)ext2_hashalloc(pip, cg, (long)ipref, mode, ext2_nodealloccg);
385
386 if (ino == 0)
387 goto noinodes;
388 error = VFS_VGET(pvp->v_mount, ino, LK_EXCLUSIVE, vpp);
389 if (error) {
390 ext2_vfree(pvp, ino, mode);
391 return (error);
392 }
393 ip = VTOI(*vpp);
394
395 /*
396 * The question is whether using VGET was such good idea at all:
397 * Linux doesn't read the old inode in when it is allocating a
398 * new one. I will set at least i_size and i_blocks to zero.
399 */
400 ip->i_flag = 0;
401 ip->i_size = 0;
402 ip->i_blocks = 0;
403 ip->i_mode = 0;
404 ip->i_flags = 0;
405 /* now we want to make sure that the block pointers are zeroed out */
406 for (i = 0; i < NDADDR; i++)
407 ip->i_db[i] = 0;
408 for (i = 0; i < NIADDR; i++)
409 ip->i_ib[i] = 0;
410
411 /*
412 * Set up a new generation number for this inode.
413 * Avoid zero values.
414 */
415 do {
416 ip->i_gen = arc4random();
417 } while (ip->i_gen == 0);
418
419 vfs_timestamp(&ts);
420 ip->i_birthtime = ts.tv_sec;
421 ip->i_birthnsec = ts.tv_nsec;
422
423 /*
424 printf("ext2_valloc: allocated inode %d\n", ino);
425 */
426 return (0);
427 noinodes:
428 EXT2_UNLOCK(ump);
429 ext2_fserr(fs, cred->cr_uid, "out of inodes");
430 uprintf("\n%s: create/symlink failed, no inodes free\n", fs->e2fs_fsmnt);
431 return (ENOSPC);
432 }
433
434 /*
435 * Find a cylinder to place a directory.
436 *
437 * The policy implemented by this algorithm is to allocate a
438 * directory inode in the same cylinder group as its parent
439 * directory, but also to reserve space for its files inodes
440 * and data. Restrict the number of directories which may be
441 * allocated one after another in the same cylinder group
442 * without intervening allocation of files.
443 *
444 * If we allocate a first level directory then force allocation
445 * in another cylinder group.
446 *
447 */
448 static u_long
449 ext2_dirpref(struct inode *pip)
450 {
451 struct m_ext2fs *fs;
452 int cg, prefcg, cgsize;
453 u_int avgifree, avgbfree, avgndir, curdirsize;
454 u_int minifree, minbfree, maxndir;
455 u_int mincg, minndir;
456 u_int dirsize, maxcontigdirs;
457
458 mtx_assert(EXT2_MTX(pip->i_ump), MA_OWNED);
459 fs = pip->i_e2fs;
460
461 avgifree = fs->e2fs->e2fs_ficount / fs->e2fs_gcount;
462 avgbfree = fs->e2fs->e2fs_fbcount / fs->e2fs_gcount;
463 avgndir = fs->e2fs_total_dir / fs->e2fs_gcount;
464
465 /*
466 * Force allocation in another cg if creating a first level dir.
467 */
468 ASSERT_VOP_LOCKED(ITOV(pip), "ext2fs_dirpref");
469 if (ITOV(pip)->v_vflag & VV_ROOT) {
470 prefcg = arc4random() % fs->e2fs_gcount;
471 mincg = prefcg;
472 minndir = fs->e2fs_ipg;
473 for (cg = prefcg; cg < fs->e2fs_gcount; cg++)
474 if (fs->e2fs_gd[cg].ext2bgd_ndirs < minndir &&
475 fs->e2fs_gd[cg].ext2bgd_nifree >= avgifree &&
476 fs->e2fs_gd[cg].ext2bgd_nbfree >= avgbfree) {
477 mincg = cg;
478 minndir = fs->e2fs_gd[cg].ext2bgd_ndirs;
479 }
480 for (cg = 0; cg < prefcg; cg++)
481 if (fs->e2fs_gd[cg].ext2bgd_ndirs < minndir &&
482 fs->e2fs_gd[cg].ext2bgd_nifree >= avgifree &&
483 fs->e2fs_gd[cg].ext2bgd_nbfree >= avgbfree) {
484 mincg = cg;
485 minndir = fs->e2fs_gd[cg].ext2bgd_ndirs;
486 }
487 return (mincg);
488 }
489 /*
490 * Count various limits which used for
491 * optimal allocation of a directory inode.
492 */
493 maxndir = min(avgndir + fs->e2fs_ipg / 16, fs->e2fs_ipg);
494 minifree = avgifree - avgifree / 4;
495 if (minifree < 1)
496 minifree = 1;
497 minbfree = avgbfree - avgbfree / 4;
498 if (minbfree < 1)
499 minbfree = 1;
500 cgsize = fs->e2fs_fsize * fs->e2fs_fpg;
501 dirsize = AVGDIRSIZE;
502 curdirsize = avgndir ? (cgsize - avgbfree * fs->e2fs_bsize) / avgndir : 0;
503 if (dirsize < curdirsize)
504 dirsize = curdirsize;
505 maxcontigdirs = min((avgbfree * fs->e2fs_bsize) / dirsize, 255);
506 maxcontigdirs = min(maxcontigdirs, fs->e2fs_ipg / AFPDIR);
507 if (maxcontigdirs == 0)
508 maxcontigdirs = 1;
509
510 /*
511 * Limit number of dirs in one cg and reserve space for
512 * regular files, but only if we have no deficit in
513 * inodes or space.
514 */
515 prefcg = ino_to_cg(fs, pip->i_number);
516 for (cg = prefcg; cg < fs->e2fs_gcount; cg++)
517 if (fs->e2fs_gd[cg].ext2bgd_ndirs < maxndir &&
518 fs->e2fs_gd[cg].ext2bgd_nifree >= minifree &&
519 fs->e2fs_gd[cg].ext2bgd_nbfree >= minbfree) {
520 if (fs->e2fs_contigdirs[cg] < maxcontigdirs)
521 return (cg);
522 }
523 for (cg = 0; cg < prefcg; cg++)
524 if (fs->e2fs_gd[cg].ext2bgd_ndirs < maxndir &&
525 fs->e2fs_gd[cg].ext2bgd_nifree >= minifree &&
526 fs->e2fs_gd[cg].ext2bgd_nbfree >= minbfree) {
527 if (fs->e2fs_contigdirs[cg] < maxcontigdirs)
528 return (cg);
529 }
530 /*
531 * This is a backstop when we have deficit in space.
532 */
533 for (cg = prefcg; cg < fs->e2fs_gcount; cg++)
534 if (fs->e2fs_gd[cg].ext2bgd_nifree >= avgifree)
535 return (cg);
536 for (cg = 0; cg < prefcg; cg++)
537 if (fs->e2fs_gd[cg].ext2bgd_nifree >= avgifree)
538 break;
539 return (cg);
540 }
541
542 /*
543 * Select the desired position for the next block in a file.
544 *
545 * we try to mimic what Remy does in inode_getblk/block_getblk
546 *
547 * we note: blocknr == 0 means that we're about to allocate either
548 * a direct block or a pointer block at the first level of indirection
549 * (In other words, stuff that will go in i_db[] or i_ib[])
550 *
551 * blocknr != 0 means that we're allocating a block that is none
552 * of the above. Then, blocknr tells us the number of the block
553 * that will hold the pointer
554 */
555 e4fs_daddr_t
556 ext2_blkpref(struct inode *ip, e2fs_lbn_t lbn, int indx, e2fs_daddr_t *bap,
557 e2fs_daddr_t blocknr)
558 {
559 int tmp;
560
561 mtx_assert(EXT2_MTX(ip->i_ump), MA_OWNED);
562
563 /*
564 * If the next block is actually what we thought it is, then set the
565 * goal to what we thought it should be.
566 */
567 if (ip->i_next_alloc_block == lbn && ip->i_next_alloc_goal != 0)
568 return ip->i_next_alloc_goal;
569
570 /*
571 * Now check whether we were provided with an array that basically
572 * tells us previous blocks to which we want to stay close.
573 */
574 if (bap)
575 for (tmp = indx - 1; tmp >= 0; tmp--)
576 if (bap[tmp])
577 return bap[tmp];
578
579 /*
580 * Else lets fall back to the blocknr or, if there is none, follow
581 * the rule that a block should be allocated near its inode.
582 */
583 return blocknr ? blocknr :
584 (e2fs_daddr_t)(ip->i_block_group *
585 EXT2_BLOCKS_PER_GROUP(ip->i_e2fs)) +
586 ip->i_e2fs->e2fs->e2fs_first_dblock;
587 }
588
589 /*
590 * Implement the cylinder overflow algorithm.
591 *
592 * The policy implemented by this algorithm is:
593 * 1) allocate the block in its requested cylinder group.
594 * 2) quadradically rehash on the cylinder group number.
595 * 3) brute force search for a free block.
596 */
597 static u_long
598 ext2_hashalloc(struct inode *ip, int cg, long pref, int size,
599 daddr_t (*allocator) (struct inode *, int, daddr_t, int))
600 {
601 struct m_ext2fs *fs;
602 ino_t result;
603 int i, icg = cg;
604
605 mtx_assert(EXT2_MTX(ip->i_ump), MA_OWNED);
606 fs = ip->i_e2fs;
607 /*
608 * 1: preferred cylinder group
609 */
610 result = (*allocator)(ip, cg, pref, size);
611 if (result)
612 return (result);
613 /*
614 * 2: quadratic rehash
615 */
616 for (i = 1; i < fs->e2fs_gcount; i *= 2) {
617 cg += i;
618 if (cg >= fs->e2fs_gcount)
619 cg -= fs->e2fs_gcount;
620 result = (*allocator)(ip, cg, 0, size);
621 if (result)
622 return (result);
623 }
624 /*
625 * 3: brute force search
626 * Note that we start at i == 2, since 0 was checked initially,
627 * and 1 is always checked in the quadratic rehash.
628 */
629 cg = (icg + 2) % fs->e2fs_gcount;
630 for (i = 2; i < fs->e2fs_gcount; i++) {
631 result = (*allocator)(ip, cg, 0, size);
632 if (result)
633 return (result);
634 cg++;
635 if (cg == fs->e2fs_gcount)
636 cg = 0;
637 }
638 return (0);
639 }
640
641 /*
642 * Determine whether a block can be allocated.
643 *
644 * Check to see if a block of the appropriate size is available,
645 * and if it is, allocate it.
646 */
647 static daddr_t
648 ext2_alloccg(struct inode *ip, int cg, daddr_t bpref, int size)
649 {
650 struct m_ext2fs *fs;
651 struct buf *bp;
652 struct ext2mount *ump;
653 daddr_t bno, runstart, runlen;
654 int bit, loc, end, error, start;
655 char *bbp;
656 /* XXX ondisk32 */
657 fs = ip->i_e2fs;
658 ump = ip->i_ump;
659 if (fs->e2fs_gd[cg].ext2bgd_nbfree == 0)
660 return (0);
661 EXT2_UNLOCK(ump);
662 error = bread(ip->i_devvp, fsbtodb(fs,
663 fs->e2fs_gd[cg].ext2bgd_b_bitmap),
664 (int)fs->e2fs_bsize, NOCRED, &bp);
665 if (error) {
666 brelse(bp);
667 EXT2_LOCK(ump);
668 return (0);
669 }
670 if (fs->e2fs_gd[cg].ext2bgd_nbfree == 0) {
671 /*
672 * Another thread allocated the last block in this
673 * group while we were waiting for the buffer.
674 */
675 brelse(bp);
676 EXT2_LOCK(ump);
677 return (0);
678 }
679 bbp = (char *)bp->b_data;
680
681 if (dtog(fs, bpref) != cg)
682 bpref = 0;
683 if (bpref != 0) {
684 bpref = dtogd(fs, bpref);
685 /*
686 * if the requested block is available, use it
687 */
688 if (isclr(bbp, bpref)) {
689 bno = bpref;
690 goto gotit;
691 }
692 }
693 /*
694 * no blocks in the requested cylinder, so take next
695 * available one in this cylinder group.
696 * first try to get 8 contigous blocks, then fall back to a single
697 * block.
698 */
699 if (bpref)
700 start = dtogd(fs, bpref) / NBBY;
701 else
702 start = 0;
703 end = howmany(fs->e2fs->e2fs_fpg, NBBY) - start;
704 retry:
705 runlen = 0;
706 runstart = 0;
707 for (loc = start; loc < end; loc++) {
708 if (bbp[loc] == (char)0xff) {
709 runlen = 0;
710 continue;
711 }
712
713 /* Start of a run, find the number of high clear bits. */
714 if (runlen == 0) {
715 bit = fls(bbp[loc]);
716 runlen = NBBY - bit;
717 runstart = loc * NBBY + bit;
718 } else if (bbp[loc] == 0) {
719 /* Continue a run. */
720 runlen += NBBY;
721 } else {
722 /*
723 * Finish the current run. If it isn't long
724 * enough, start a new one.
725 */
726 bit = ffs(bbp[loc]) - 1;
727 runlen += bit;
728 if (runlen >= 8) {
729 bno = runstart;
730 goto gotit;
731 }
732
733 /* Run was too short, start a new one. */
734 bit = fls(bbp[loc]);
735 runlen = NBBY - bit;
736 runstart = loc * NBBY + bit;
737 }
738
739 /* If the current run is long enough, use it. */
740 if (runlen >= 8) {
741 bno = runstart;
742 goto gotit;
743 }
744 }
745 if (start != 0) {
746 end = start;
747 start = 0;
748 goto retry;
749 }
750 bno = ext2_mapsearch(fs, bbp, bpref);
751 if (bno < 0) {
752 brelse(bp);
753 EXT2_LOCK(ump);
754 return (0);
755 }
756 gotit:
757 #ifdef INVARIANTS
758 if (isset(bbp, bno)) {
759 printf("ext2fs_alloccgblk: cg=%d bno=%jd fs=%s\n",
760 cg, (intmax_t)bno, fs->e2fs_fsmnt);
761 panic("ext2fs_alloccg: dup alloc");
762 }
763 #endif
764 setbit(bbp, bno);
765 EXT2_LOCK(ump);
766 ext2_clusteracct(fs, bbp, cg, bno, -1);
767 fs->e2fs->e2fs_fbcount--;
768 fs->e2fs_gd[cg].ext2bgd_nbfree--;
769 fs->e2fs_fmod = 1;
770 EXT2_UNLOCK(ump);
771 bdwrite(bp);
772 return (cg * fs->e2fs->e2fs_fpg + fs->e2fs->e2fs_first_dblock + bno);
773 }
774
775 /*
776 * Determine whether a cluster can be allocated.
777 */
778 static daddr_t
779 ext2_clusteralloc(struct inode *ip, int cg, daddr_t bpref, int len)
780 {
781 struct m_ext2fs *fs;
782 struct ext2mount *ump;
783 struct buf *bp;
784 char *bbp;
785 int bit, error, got, i, loc, run;
786 int32_t *lp;
787 daddr_t bno;
788
789 fs = ip->i_e2fs;
790 ump = ip->i_ump;
791
792 if (fs->e2fs_maxcluster[cg] < len)
793 return (0);
794
795 EXT2_UNLOCK(ump);
796 error = bread(ip->i_devvp,
797 fsbtodb(fs, fs->e2fs_gd[cg].ext2bgd_b_bitmap),
798 (int)fs->e2fs_bsize, NOCRED, &bp);
799 if (error)
800 goto fail_lock;
801
802 bbp = (char *)bp->b_data;
803 EXT2_LOCK(ump);
804 /*
805 * Check to see if a cluster of the needed size (or bigger) is
806 * available in this cylinder group.
807 */
808 lp = &fs->e2fs_clustersum[cg].cs_sum[len];
809 for (i = len; i <= fs->e2fs_contigsumsize; i++)
810 if (*lp++ > 0)
811 break;
812 if (i > fs->e2fs_contigsumsize) {
813 /*
814 * Update the cluster summary information to reflect
815 * the true maximum-sized cluster so that future cluster
816 * allocation requests can avoid reading the bitmap only
817 * to find no cluster.
818 */
819 lp = &fs->e2fs_clustersum[cg].cs_sum[len - 1];
820 for (i = len - 1; i > 0; i--)
821 if (*lp-- > 0)
822 break;
823 fs->e2fs_maxcluster[cg] = i;
824 goto fail;
825 }
826 EXT2_UNLOCK(ump);
827
828 /* Search the bitmap to find a big enough cluster like in FFS. */
829 if (dtog(fs, bpref) != cg)
830 bpref = 0;
831 if (bpref != 0)
832 bpref = dtogd(fs, bpref);
833 loc = bpref / NBBY;
834 bit = 1 << (bpref % NBBY);
835 for (run = 0, got = bpref; got < fs->e2fs->e2fs_fpg; got++) {
836 if ((bbp[loc] & bit) != 0)
837 run = 0;
838 else {
839 run++;
840 if (run == len)
841 break;
842 }
843 if ((got & (NBBY - 1)) != (NBBY - 1))
844 bit <<= 1;
845 else {
846 loc++;
847 bit = 1;
848 }
849 }
850
851 if (got >= fs->e2fs->e2fs_fpg)
852 goto fail_lock;
853
854 /* Allocate the cluster that we found. */
855 for (i = 1; i < len; i++)
856 if (!isclr(bbp, got - run + i))
857 panic("ext2_clusteralloc: map mismatch");
858
859 bno = got - run + 1;
860 if (bno >= fs->e2fs->e2fs_fpg)
861 panic("ext2_clusteralloc: allocated out of group");
862
863 EXT2_LOCK(ump);
864 for (i = 0; i < len; i += fs->e2fs_fpb) {
865 setbit(bbp, bno + i);
866 ext2_clusteracct(fs, bbp, cg, bno + i, -1);
867 fs->e2fs->e2fs_fbcount--;
868 fs->e2fs_gd[cg].ext2bgd_nbfree--;
869 }
870 fs->e2fs_fmod = 1;
871 EXT2_UNLOCK(ump);
872
873 bdwrite(bp);
874 return (cg * fs->e2fs->e2fs_fpg + fs->e2fs->e2fs_first_dblock + bno);
875
876 fail_lock:
877 EXT2_LOCK(ump);
878 fail:
879 brelse(bp);
880 return (0);
881 }
882
883 /*
884 * Determine whether an inode can be allocated.
885 *
886 * Check to see if an inode is available, and if it is,
887 * allocate it using tode in the specified cylinder group.
888 */
889 static daddr_t
890 ext2_nodealloccg(struct inode *ip, int cg, daddr_t ipref, int mode)
891 {
892 struct m_ext2fs *fs;
893 struct buf *bp;
894 struct ext2mount *ump;
895 int error, start, len;
896 char *ibp, *loc;
897
898 ipref--; /* to avoid a lot of (ipref -1) */
899 if (ipref == -1)
900 ipref = 0;
901 fs = ip->i_e2fs;
902 ump = ip->i_ump;
903 if (fs->e2fs_gd[cg].ext2bgd_nifree == 0)
904 return (0);
905 EXT2_UNLOCK(ump);
906 error = bread(ip->i_devvp, fsbtodb(fs,
907 fs->e2fs_gd[cg].ext2bgd_i_bitmap),
908 (int)fs->e2fs_bsize, NOCRED, &bp);
909 if (error) {
910 brelse(bp);
911 EXT2_LOCK(ump);
912 return (0);
913 }
914 if (fs->e2fs_gd[cg].ext2bgd_nifree == 0) {
915 /*
916 * Another thread allocated the last i-node in this
917 * group while we were waiting for the buffer.
918 */
919 brelse(bp);
920 EXT2_LOCK(ump);
921 return (0);
922 }
923 ibp = (char *)bp->b_data;
924 if (ipref) {
925 ipref %= fs->e2fs->e2fs_ipg;
926 if (isclr(ibp, ipref))
927 goto gotit;
928 }
929 start = ipref / NBBY;
930 len = howmany(fs->e2fs->e2fs_ipg - ipref, NBBY);
931 loc = memcchr(&ibp[start], 0xff, len);
932 if (loc == NULL) {
933 len = start + 1;
934 start = 0;
935 loc = memcchr(&ibp[start], 0xff, len);
936 if (loc == NULL) {
937 printf("cg = %d, ipref = %lld, fs = %s\n",
938 cg, (long long)ipref, fs->e2fs_fsmnt);
939 panic("ext2fs_nodealloccg: map corrupted");
940 /* NOTREACHED */
941 }
942 }
943 ipref = (loc - ibp) * NBBY + ffs(~*loc) - 1;
944 gotit:
945 setbit(ibp, ipref);
946 EXT2_LOCK(ump);
947 fs->e2fs_gd[cg].ext2bgd_nifree--;
948 fs->e2fs->e2fs_ficount--;
949 fs->e2fs_fmod = 1;
950 if ((mode & IFMT) == IFDIR) {
951 fs->e2fs_gd[cg].ext2bgd_ndirs++;
952 fs->e2fs_total_dir++;
953 }
954 EXT2_UNLOCK(ump);
955 bdwrite(bp);
956 return (cg * fs->e2fs->e2fs_ipg + ipref + 1);
957 }
958
959 /*
960 * Free a block or fragment.
961 *
962 */
963 void
964 ext2_blkfree(struct inode *ip, e4fs_daddr_t bno, long size)
965 {
966 struct m_ext2fs *fs;
967 struct buf *bp;
968 struct ext2mount *ump;
969 int cg, error;
970 char *bbp;
971
972 fs = ip->i_e2fs;
973 ump = ip->i_ump;
974 cg = dtog(fs, bno);
975 if ((u_int)bno >= fs->e2fs->e2fs_bcount) {
976 printf("bad block %lld, ino %ju\n", (long long)bno,
977 (uintmax_t)ip->i_number);
978 ext2_fserr(fs, ip->i_uid, "bad block");
979 return;
980 }
981 error = bread(ip->i_devvp,
982 fsbtodb(fs, fs->e2fs_gd[cg].ext2bgd_b_bitmap),
983 (int)fs->e2fs_bsize, NOCRED, &bp);
984 if (error) {
985 brelse(bp);
986 return;
987 }
988 bbp = (char *)bp->b_data;
989 bno = dtogd(fs, bno);
990 if (isclr(bbp, bno)) {
991 printf("block = %lld, fs = %s\n",
992 (long long)bno, fs->e2fs_fsmnt);
993 panic("ext2_blkfree: freeing free block");
994 }
995 clrbit(bbp, bno);
996 EXT2_LOCK(ump);
997 ext2_clusteracct(fs, bbp, cg, bno, 1);
998 fs->e2fs->e2fs_fbcount++;
999 fs->e2fs_gd[cg].ext2bgd_nbfree++;
1000 fs->e2fs_fmod = 1;
1001 EXT2_UNLOCK(ump);
1002 bdwrite(bp);
1003 }
1004
1005 /*
1006 * Free an inode.
1007 *
1008 */
1009 int
1010 ext2_vfree(struct vnode *pvp, ino_t ino, int mode)
1011 {
1012 struct m_ext2fs *fs;
1013 struct inode *pip;
1014 struct buf *bp;
1015 struct ext2mount *ump;
1016 int error, cg;
1017 char *ibp;
1018
1019 pip = VTOI(pvp);
1020 fs = pip->i_e2fs;
1021 ump = pip->i_ump;
1022 if ((u_int)ino > fs->e2fs_ipg * fs->e2fs_gcount)
1023 panic("ext2_vfree: range: devvp = %p, ino = %ju, fs = %s",
1024 pip->i_devvp, (uintmax_t)ino, fs->e2fs_fsmnt);
1025
1026 cg = ino_to_cg(fs, ino);
1027 error = bread(pip->i_devvp,
1028 fsbtodb(fs, fs->e2fs_gd[cg].ext2bgd_i_bitmap),
1029 (int)fs->e2fs_bsize, NOCRED, &bp);
1030 if (error) {
1031 brelse(bp);
1032 return (0);
1033 }
1034 ibp = (char *)bp->b_data;
1035 ino = (ino - 1) % fs->e2fs->e2fs_ipg;
1036 if (isclr(ibp, ino)) {
1037 printf("ino = %llu, fs = %s\n",
1038 (unsigned long long)ino, fs->e2fs_fsmnt);
1039 if (fs->e2fs_ronly == 0)
1040 panic("ext2_vfree: freeing free inode");
1041 }
1042 clrbit(ibp, ino);
1043 EXT2_LOCK(ump);
1044 fs->e2fs->e2fs_ficount++;
1045 fs->e2fs_gd[cg].ext2bgd_nifree++;
1046 if ((mode & IFMT) == IFDIR) {
1047 fs->e2fs_gd[cg].ext2bgd_ndirs--;
1048 fs->e2fs_total_dir--;
1049 }
1050 fs->e2fs_fmod = 1;
1051 EXT2_UNLOCK(ump);
1052 bdwrite(bp);
1053 return (0);
1054 }
1055
1056 /*
1057 * Find a block in the specified cylinder group.
1058 *
1059 * It is a panic if a request is made to find a block if none are
1060 * available.
1061 */
1062 static daddr_t
1063 ext2_mapsearch(struct m_ext2fs *fs, char *bbp, daddr_t bpref)
1064 {
1065 char *loc;
1066 int start, len;
1067
1068 /*
1069 * find the fragment by searching through the free block
1070 * map for an appropriate bit pattern
1071 */
1072 if (bpref)
1073 start = dtogd(fs, bpref) / NBBY;
1074 else
1075 start = 0;
1076 len = howmany(fs->e2fs->e2fs_fpg, NBBY) - start;
1077 loc = memcchr(&bbp[start], 0xff, len);
1078 if (loc == NULL) {
1079 len = start + 1;
1080 start = 0;
1081 loc = memcchr(&bbp[start], 0xff, len);
1082 if (loc == NULL) {
1083 printf("start = %d, len = %d, fs = %s\n",
1084 start, len, fs->e2fs_fsmnt);
1085 panic("ext2_mapsearch: map corrupted");
1086 /* NOTREACHED */
1087 }
1088 }
1089 return ((loc - bbp) * NBBY + ffs(~*loc) - 1);
1090 }
1091
1092 /*
1093 * Fserr prints the name of a filesystem with an error diagnostic.
1094 *
1095 * The form of the error message is:
1096 * fs: error message
1097 */
1098 static void
1099 ext2_fserr(struct m_ext2fs *fs, uid_t uid, char *cp)
1100 {
1101
1102 log(LOG_ERR, "uid %u on %s: %s\n", uid, fs->e2fs_fsmnt, cp);
1103 }
1104
1105 int
1106 cg_has_sb(int i)
1107 {
1108 int a3, a5, a7;
1109
1110 if (i == 0 || i == 1)
1111 return 1;
1112 for (a3 = 3, a5 = 5, a7 = 7;
1113 a3 <= i || a5 <= i || a7 <= i;
1114 a3 *= 3, a5 *= 5, a7 *= 7)
1115 if (i == a3 || i == a5 || i == a7)
1116 return 1;
1117 return 0;
1118 }
Cache object: da5acd395953d1259850a7481cf8a442
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