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/10.3/sys/fs/ext2fs/ext2_alloc.c 277832 2015-01-28 15:36:24Z 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 *bnp = 0;
91 fs = ip->i_e2fs;
92 ump = ip->i_ump;
93 mtx_assert(EXT2_MTX(ump), MA_OWNED);
94 #ifdef INVARIANTS
95 if ((u_int)size > fs->e2fs_bsize || blkoff(fs, size) != 0) {
96 vn_printf(ip->i_devvp, "bsize = %lu, size = %d, fs = %s\n",
97 (long unsigned int)fs->e2fs_bsize, size, fs->e2fs_fsmnt);
98 panic("ext2_alloc: bad size");
99 }
100 if (cred == NOCRED)
101 panic("ext2_alloc: missing credential");
102 #endif /* INVARIANTS */
103 if (size == fs->e2fs_bsize && fs->e2fs->e2fs_fbcount == 0)
104 goto nospace;
105 if (cred->cr_uid != 0 &&
106 fs->e2fs->e2fs_fbcount < fs->e2fs->e2fs_rbcount)
107 goto nospace;
108 if (bpref >= fs->e2fs->e2fs_bcount)
109 bpref = 0;
110 if (bpref == 0)
111 cg = ino_to_cg(fs, ip->i_number);
112 else
113 cg = dtog(fs, bpref);
114 bno = (daddr_t)ext2_hashalloc(ip, cg, bpref, fs->e2fs_bsize,
115 ext2_alloccg);
116 if (bno > 0) {
117 /* set next_alloc fields as done in block_getblk */
118 ip->i_next_alloc_block = lbn;
119 ip->i_next_alloc_goal = bno;
120
121 ip->i_blocks += btodb(fs->e2fs_bsize);
122 ip->i_flag |= IN_CHANGE | IN_UPDATE;
123 *bnp = bno;
124 return (0);
125 }
126 nospace:
127 EXT2_UNLOCK(ump);
128 ext2_fserr(fs, cred->cr_uid, "filesystem full");
129 uprintf("\n%s: write failed, filesystem is full\n", fs->e2fs_fsmnt);
130 return (ENOSPC);
131 }
132
133 /*
134 * Reallocate a sequence of blocks into a contiguous sequence of blocks.
135 *
136 * The vnode and an array of buffer pointers for a range of sequential
137 * logical blocks to be made contiguous is given. The allocator attempts
138 * to find a range of sequential blocks starting as close as possible to
139 * an fs_rotdelay offset from the end of the allocation for the logical
140 * block immediately preceding the current range. If successful, the
141 * physical block numbers in the buffer pointers and in the inode are
142 * changed to reflect the new allocation. If unsuccessful, the allocation
143 * is left unchanged. The success in doing the reallocation is returned.
144 * Note that the error return is not reflected back to the user. Rather
145 * the previous block allocation will be used.
146 */
147
148 static SYSCTL_NODE(_vfs, OID_AUTO, ext2fs, CTLFLAG_RW, 0, "EXT2FS filesystem");
149
150 static int doasyncfree = 1;
151 SYSCTL_INT(_vfs_ext2fs, OID_AUTO, doasyncfree, CTLFLAG_RW, &doasyncfree, 0,
152 "Use asychronous writes to update block pointers when freeing blocks");
153
154 static int doreallocblks = 1;
155 SYSCTL_INT(_vfs_ext2fs, OID_AUTO, doreallocblks, CTLFLAG_RW, &doreallocblks, 0, "");
156
157 int
158 ext2_reallocblks(struct vop_reallocblks_args *ap)
159 {
160 struct m_ext2fs *fs;
161 struct inode *ip;
162 struct vnode *vp;
163 struct buf *sbp, *ebp;
164 uint32_t *bap, *sbap, *ebap = 0;
165 struct ext2mount *ump;
166 struct cluster_save *buflist;
167 struct indir start_ap[NIADDR + 1], end_ap[NIADDR + 1], *idp;
168 e2fs_lbn_t start_lbn, end_lbn;
169 int soff;
170 e2fs_daddr_t newblk, blkno;
171 int i, len, start_lvl, end_lvl, pref, ssize;
172
173 if (doreallocblks == 0)
174 return (ENOSPC);
175
176 vp = ap->a_vp;
177 ip = VTOI(vp);
178 fs = ip->i_e2fs;
179 ump = ip->i_ump;
180
181 if (fs->e2fs_contigsumsize <= 0)
182 return (ENOSPC);
183
184 buflist = ap->a_buflist;
185 len = buflist->bs_nchildren;
186 start_lbn = buflist->bs_children[0]->b_lblkno;
187 end_lbn = start_lbn + len - 1;
188 #ifdef INVARIANTS
189 for (i = 1; i < len; i++)
190 if (buflist->bs_children[i]->b_lblkno != start_lbn + i)
191 panic("ext2_reallocblks: non-cluster");
192 #endif
193 /*
194 * If the cluster crosses the boundary for the first indirect
195 * block, leave space for the indirect block. Indirect blocks
196 * are initially laid out in a position after the last direct
197 * block. Block reallocation would usually destroy locality by
198 * moving the indirect block out of the way to make room for
199 * data blocks if we didn't compensate here. We should also do
200 * this for other indirect block boundaries, but it is only
201 * important for the first one.
202 */
203 if (start_lbn < NDADDR && end_lbn >= NDADDR)
204 return (ENOSPC);
205 /*
206 * If the latest allocation is in a new cylinder group, assume that
207 * the filesystem has decided to move and do not force it back to
208 * the previous cylinder group.
209 */
210 if (dtog(fs, dbtofsb(fs, buflist->bs_children[0]->b_blkno)) !=
211 dtog(fs, dbtofsb(fs, buflist->bs_children[len - 1]->b_blkno)))
212 return (ENOSPC);
213 if (ext2_getlbns(vp, start_lbn, start_ap, &start_lvl) ||
214 ext2_getlbns(vp, end_lbn, end_ap, &end_lvl))
215 return (ENOSPC);
216 /*
217 * Get the starting offset and block map for the first block.
218 */
219 if (start_lvl == 0) {
220 sbap = &ip->i_db[0];
221 soff = start_lbn;
222 } else {
223 idp = &start_ap[start_lvl - 1];
224 if (bread(vp, idp->in_lbn, (int)fs->e2fs_bsize, NOCRED, &sbp)) {
225 brelse(sbp);
226 return (ENOSPC);
227 }
228 sbap = (u_int *)sbp->b_data;
229 soff = idp->in_off;
230 }
231 /*
232 * If the block range spans two block maps, get the second map.
233 */
234 if (end_lvl == 0 || (idp = &end_ap[end_lvl - 1])->in_off + 1 >= len) {
235 ssize = len;
236 } else {
237 #ifdef INVARIANTS
238 if (start_ap[start_lvl-1].in_lbn == idp->in_lbn)
239 panic("ext2_reallocblks: start == end");
240 #endif
241 ssize = len - (idp->in_off + 1);
242 if (bread(vp, idp->in_lbn, (int)fs->e2fs_bsize, NOCRED, &ebp))
243 goto fail;
244 ebap = (u_int *)ebp->b_data;
245 }
246 /*
247 * Find the preferred location for the cluster.
248 */
249 EXT2_LOCK(ump);
250 pref = ext2_blkpref(ip, start_lbn, soff, sbap, 0);
251 /*
252 * Search the block map looking for an allocation of the desired size.
253 */
254 if ((newblk = (e2fs_daddr_t)ext2_hashalloc(ip, dtog(fs, pref), pref,
255 len, ext2_clusteralloc)) == 0){
256 EXT2_UNLOCK(ump);
257 goto fail;
258 }
259 /*
260 * We have found a new contiguous block.
261 *
262 * First we have to replace the old block pointers with the new
263 * block pointers in the inode and indirect blocks associated
264 * with the file.
265 */
266 #ifdef DEBUG
267 printf("realloc: ino %d, lbns %jd-%jd\n\told:", ip->i_number,
268 (intmax_t)start_lbn, (intmax_t)end_lbn);
269 #endif /* DEBUG */
270 blkno = newblk;
271 for (bap = &sbap[soff], i = 0; i < len; i++, blkno += fs->e2fs_fpb) {
272 if (i == ssize) {
273 bap = ebap;
274 soff = -i;
275 }
276 #ifdef INVARIANTS
277 if (buflist->bs_children[i]->b_blkno != fsbtodb(fs, *bap))
278 panic("ext2_reallocblks: alloc mismatch");
279 #endif
280 #ifdef DEBUG
281 printf(" %d,", *bap);
282 #endif /* DEBUG */
283 *bap++ = blkno;
284 }
285 /*
286 * Next we must write out the modified inode and indirect blocks.
287 * For strict correctness, the writes should be synchronous since
288 * the old block values may have been written to disk. In practise
289 * they are almost never written, but if we are concerned about
290 * strict correctness, the `doasyncfree' flag should be set to zero.
291 *
292 * The test on `doasyncfree' should be changed to test a flag
293 * that shows whether the associated buffers and inodes have
294 * been written. The flag should be set when the cluster is
295 * started and cleared whenever the buffer or inode is flushed.
296 * We can then check below to see if it is set, and do the
297 * synchronous write only when it has been cleared.
298 */
299 if (sbap != &ip->i_db[0]) {
300 if (doasyncfree)
301 bdwrite(sbp);
302 else
303 bwrite(sbp);
304 } else {
305 ip->i_flag |= IN_CHANGE | IN_UPDATE;
306 if (!doasyncfree)
307 ext2_update(vp, 1);
308 }
309 if (ssize < len) {
310 if (doasyncfree)
311 bdwrite(ebp);
312 else
313 bwrite(ebp);
314 }
315 /*
316 * Last, free the old blocks and assign the new blocks to the buffers.
317 */
318 #ifdef DEBUG
319 printf("\n\tnew:");
320 #endif /* DEBUG */
321 for (blkno = newblk, i = 0; i < len; i++, blkno += fs->e2fs_fpb) {
322 ext2_blkfree(ip, dbtofsb(fs, buflist->bs_children[i]->b_blkno),
323 fs->e2fs_bsize);
324 buflist->bs_children[i]->b_blkno = fsbtodb(fs, blkno);
325 #ifdef DEBUG
326 printf(" %d,", blkno);
327 #endif /* DEBUG */
328 }
329 #ifdef DEBUG
330 printf("\n");
331 #endif /* DEBUG */
332 return (0);
333
334 fail:
335 if (ssize < len)
336 brelse(ebp);
337 if (sbap != &ip->i_db[0])
338 brelse(sbp);
339 return (ENOSPC);
340 }
341
342 /*
343 * Allocate an inode in the filesystem.
344 *
345 */
346 int
347 ext2_valloc(struct vnode *pvp, int mode, struct ucred *cred, struct vnode **vpp)
348 {
349 struct timespec ts;
350 struct inode *pip;
351 struct m_ext2fs *fs;
352 struct inode *ip;
353 struct ext2mount *ump;
354 ino_t ino, ipref;
355 int i, error, cg;
356
357 *vpp = NULL;
358 pip = VTOI(pvp);
359 fs = pip->i_e2fs;
360 ump = pip->i_ump;
361
362 EXT2_LOCK(ump);
363 if (fs->e2fs->e2fs_ficount == 0)
364 goto noinodes;
365 /*
366 * If it is a directory then obtain a cylinder group based on
367 * ext2_dirpref else obtain it using ino_to_cg. The preferred inode is
368 * always the next inode.
369 */
370 if ((mode & IFMT) == IFDIR) {
371 cg = ext2_dirpref(pip);
372 if (fs->e2fs_contigdirs[cg] < 255)
373 fs->e2fs_contigdirs[cg]++;
374 } else {
375 cg = ino_to_cg(fs, pip->i_number);
376 if (fs->e2fs_contigdirs[cg] > 0)
377 fs->e2fs_contigdirs[cg]--;
378 }
379 ipref = cg * fs->e2fs->e2fs_ipg + 1;
380 ino = (ino_t)ext2_hashalloc(pip, cg, (long)ipref, mode, ext2_nodealloccg);
381
382 if (ino == 0)
383 goto noinodes;
384 error = VFS_VGET(pvp->v_mount, ino, LK_EXCLUSIVE, vpp);
385 if (error) {
386 ext2_vfree(pvp, ino, mode);
387 return (error);
388 }
389 ip = VTOI(*vpp);
390
391 /*
392 * The question is whether using VGET was such good idea at all:
393 * Linux doesn't read the old inode in when it is allocating a
394 * new one. I will set at least i_size and i_blocks to zero.
395 */
396 ip->i_size = 0;
397 ip->i_blocks = 0;
398 ip->i_mode = 0;
399 ip->i_flags = 0;
400 /* now we want to make sure that the block pointers are zeroed out */
401 for (i = 0; i < NDADDR; i++)
402 ip->i_db[i] = 0;
403 for (i = 0; i < NIADDR; i++)
404 ip->i_ib[i] = 0;
405
406 /*
407 * Set up a new generation number for this inode.
408 * XXX check if this makes sense in ext2
409 */
410 if (ip->i_gen == 0 || ++ip->i_gen == 0)
411 ip->i_gen = random() / 2 + 1;
412
413 vfs_timestamp(&ts);
414 ip->i_birthtime = ts.tv_sec;
415 ip->i_birthnsec = ts.tv_nsec;
416
417 /*
418 printf("ext2_valloc: allocated inode %d\n", ino);
419 */
420 return (0);
421 noinodes:
422 EXT2_UNLOCK(ump);
423 ext2_fserr(fs, cred->cr_uid, "out of inodes");
424 uprintf("\n%s: create/symlink failed, no inodes free\n", fs->e2fs_fsmnt);
425 return (ENOSPC);
426 }
427
428 /*
429 * Find a cylinder to place a directory.
430 *
431 * The policy implemented by this algorithm is to allocate a
432 * directory inode in the same cylinder group as its parent
433 * directory, but also to reserve space for its files inodes
434 * and data. Restrict the number of directories which may be
435 * allocated one after another in the same cylinder group
436 * without intervening allocation of files.
437 *
438 * If we allocate a first level directory then force allocation
439 * in another cylinder group.
440 *
441 */
442 static u_long
443 ext2_dirpref(struct inode *pip)
444 {
445 struct m_ext2fs *fs;
446 int cg, prefcg, cgsize;
447 u_int avgifree, avgbfree, avgndir, curdirsize;
448 u_int minifree, minbfree, maxndir;
449 u_int mincg, minndir;
450 u_int dirsize, maxcontigdirs;
451
452 mtx_assert(EXT2_MTX(pip->i_ump), MA_OWNED);
453 fs = pip->i_e2fs;
454
455 avgifree = fs->e2fs->e2fs_ficount / fs->e2fs_gcount;
456 avgbfree = fs->e2fs->e2fs_fbcount / fs->e2fs_gcount;
457 avgndir = fs->e2fs_total_dir / fs->e2fs_gcount;
458
459 /*
460 * Force allocation in another cg if creating a first level dir.
461 */
462 ASSERT_VOP_LOCKED(ITOV(pip), "ext2fs_dirpref");
463 if (ITOV(pip)->v_vflag & VV_ROOT) {
464 prefcg = arc4random() % fs->e2fs_gcount;
465 mincg = prefcg;
466 minndir = fs->e2fs_ipg;
467 for (cg = prefcg; cg < fs->e2fs_gcount; cg++)
468 if (fs->e2fs_gd[cg].ext2bgd_ndirs < minndir &&
469 fs->e2fs_gd[cg].ext2bgd_nifree >= avgifree &&
470 fs->e2fs_gd[cg].ext2bgd_nbfree >= avgbfree) {
471 mincg = cg;
472 minndir = fs->e2fs_gd[cg].ext2bgd_ndirs;
473 }
474 for (cg = 0; cg < prefcg; cg++)
475 if (fs->e2fs_gd[cg].ext2bgd_ndirs < minndir &&
476 fs->e2fs_gd[cg].ext2bgd_nifree >= avgifree &&
477 fs->e2fs_gd[cg].ext2bgd_nbfree >= avgbfree) {
478 mincg = cg;
479 minndir = fs->e2fs_gd[cg].ext2bgd_ndirs;
480 }
481
482 return (mincg);
483 }
484
485 /*
486 * Count various limits which used for
487 * optimal allocation of a directory inode.
488 */
489 maxndir = min(avgndir + fs->e2fs_ipg / 16, fs->e2fs_ipg);
490 minifree = avgifree - avgifree / 4;
491 if (minifree < 1)
492 minifree = 1;
493 minbfree = avgbfree - avgbfree / 4;
494 if (minbfree < 1)
495 minbfree = 1;
496 cgsize = fs->e2fs_fsize * fs->e2fs_fpg;
497 dirsize = AVGDIRSIZE;
498 curdirsize = avgndir ? (cgsize - avgbfree * fs->e2fs_bsize) / avgndir : 0;
499 if (dirsize < curdirsize)
500 dirsize = curdirsize;
501 maxcontigdirs = min((avgbfree * fs->e2fs_bsize) / dirsize, 255);
502 maxcontigdirs = min(maxcontigdirs, fs->e2fs_ipg / AFPDIR);
503 if (maxcontigdirs == 0)
504 maxcontigdirs = 1;
505
506 /*
507 * Limit number of dirs in one cg and reserve space for
508 * regular files, but only if we have no deficit in
509 * inodes or space.
510 */
511 prefcg = ino_to_cg(fs, pip->i_number);
512 for (cg = prefcg; cg < fs->e2fs_gcount; cg++)
513 if (fs->e2fs_gd[cg].ext2bgd_ndirs < maxndir &&
514 fs->e2fs_gd[cg].ext2bgd_nifree >= minifree &&
515 fs->e2fs_gd[cg].ext2bgd_nbfree >= minbfree) {
516 if (fs->e2fs_contigdirs[cg] < maxcontigdirs)
517 return (cg);
518 }
519 for (cg = 0; cg < prefcg; cg++)
520 if (fs->e2fs_gd[cg].ext2bgd_ndirs < maxndir &&
521 fs->e2fs_gd[cg].ext2bgd_nifree >= minifree &&
522 fs->e2fs_gd[cg].ext2bgd_nbfree >= minbfree) {
523 if (fs->e2fs_contigdirs[cg] < maxcontigdirs)
524 return (cg);
525 }
526 /*
527 * This is a backstop when we have deficit in space.
528 */
529 for (cg = prefcg; cg < fs->e2fs_gcount; cg++)
530 if (fs->e2fs_gd[cg].ext2bgd_nifree >= avgifree)
531 return (cg);
532 for (cg = 0; cg < prefcg; cg++)
533 if (fs->e2fs_gd[cg].ext2bgd_nifree >= avgifree)
534 break;
535 return (cg);
536 }
537
538 /*
539 * Select the desired position for the next block in a file.
540 *
541 * we try to mimic what Remy does in inode_getblk/block_getblk
542 *
543 * we note: blocknr == 0 means that we're about to allocate either
544 * a direct block or a pointer block at the first level of indirection
545 * (In other words, stuff that will go in i_db[] or i_ib[])
546 *
547 * blocknr != 0 means that we're allocating a block that is none
548 * of the above. Then, blocknr tells us the number of the block
549 * that will hold the pointer
550 */
551 e4fs_daddr_t
552 ext2_blkpref(struct inode *ip, e2fs_lbn_t lbn, int indx, e2fs_daddr_t *bap,
553 e2fs_daddr_t blocknr)
554 {
555 int tmp;
556 mtx_assert(EXT2_MTX(ip->i_ump), MA_OWNED);
557
558 /* if the next block is actually what we thought it is,
559 then set the goal to what we thought it should be
560 */
561 if (ip->i_next_alloc_block == lbn && ip->i_next_alloc_goal != 0)
562 return ip->i_next_alloc_goal;
563
564 /* now check whether we were provided with an array that basically
565 tells us previous blocks to which we want to stay closeby
566 */
567 if (bap)
568 for (tmp = indx - 1; tmp >= 0; tmp--)
569 if (bap[tmp])
570 return bap[tmp];
571
572 /* else let's fall back to the blocknr, or, if there is none,
573 follow the rule that a block should be allocated near its inode
574 */
575 return blocknr ? blocknr :
576 (e2fs_daddr_t)(ip->i_block_group *
577 EXT2_BLOCKS_PER_GROUP(ip->i_e2fs)) +
578 ip->i_e2fs->e2fs->e2fs_first_dblock;
579 }
580
581 /*
582 * Implement the cylinder overflow algorithm.
583 *
584 * The policy implemented by this algorithm is:
585 * 1) allocate the block in its requested cylinder group.
586 * 2) quadradically rehash on the cylinder group number.
587 * 3) brute force search for a free block.
588 */
589 static u_long
590 ext2_hashalloc(struct inode *ip, int cg, long pref, int size,
591 daddr_t (*allocator)(struct inode *, int, daddr_t, int))
592 {
593 struct m_ext2fs *fs;
594 ino_t result;
595 int i, icg = cg;
596
597 mtx_assert(EXT2_MTX(ip->i_ump), MA_OWNED);
598 fs = ip->i_e2fs;
599 /*
600 * 1: preferred cylinder group
601 */
602 result = (*allocator)(ip, cg, pref, size);
603 if (result)
604 return (result);
605 /*
606 * 2: quadratic rehash
607 */
608 for (i = 1; i < fs->e2fs_gcount; i *= 2) {
609 cg += i;
610 if (cg >= fs->e2fs_gcount)
611 cg -= fs->e2fs_gcount;
612 result = (*allocator)(ip, cg, 0, size);
613 if (result)
614 return (result);
615 }
616 /*
617 * 3: brute force search
618 * Note that we start at i == 2, since 0 was checked initially,
619 * and 1 is always checked in the quadratic rehash.
620 */
621 cg = (icg + 2) % fs->e2fs_gcount;
622 for (i = 2; i < fs->e2fs_gcount; i++) {
623 result = (*allocator)(ip, cg, 0, size);
624 if (result)
625 return (result);
626 cg++;
627 if (cg == fs->e2fs_gcount)
628 cg = 0;
629 }
630 return (0);
631 }
632
633 /*
634 * Determine whether a block can be allocated.
635 *
636 * Check to see if a block of the appropriate size is available,
637 * and if it is, allocate it.
638 */
639 static daddr_t
640 ext2_alloccg(struct inode *ip, int cg, daddr_t bpref, int size)
641 {
642 struct m_ext2fs *fs;
643 struct buf *bp;
644 struct ext2mount *ump;
645 daddr_t bno, runstart, runlen;
646 int bit, loc, end, error, start;
647 char *bbp;
648 /* XXX ondisk32 */
649 fs = ip->i_e2fs;
650 ump = ip->i_ump;
651 if (fs->e2fs_gd[cg].ext2bgd_nbfree == 0)
652 return (0);
653 EXT2_UNLOCK(ump);
654 error = bread(ip->i_devvp, fsbtodb(fs,
655 fs->e2fs_gd[cg].ext2bgd_b_bitmap),
656 (int)fs->e2fs_bsize, NOCRED, &bp);
657 if (error) {
658 brelse(bp);
659 EXT2_LOCK(ump);
660 return (0);
661 }
662 if (fs->e2fs_gd[cg].ext2bgd_nbfree == 0) {
663 /*
664 * Another thread allocated the last block in this
665 * group while we were waiting for the buffer.
666 */
667 brelse(bp);
668 EXT2_LOCK(ump);
669 return (0);
670 }
671 bbp = (char *)bp->b_data;
672
673 if (dtog(fs, bpref) != cg)
674 bpref = 0;
675 if (bpref != 0) {
676 bpref = dtogd(fs, bpref);
677 /*
678 * if the requested block is available, use it
679 */
680 if (isclr(bbp, bpref)) {
681 bno = bpref;
682 goto gotit;
683 }
684 }
685 /*
686 * no blocks in the requested cylinder, so take next
687 * available one in this cylinder group.
688 * first try to get 8 contigous blocks, then fall back to a single
689 * block.
690 */
691 if (bpref)
692 start = dtogd(fs, bpref) / NBBY;
693 else
694 start = 0;
695 end = howmany(fs->e2fs->e2fs_fpg, NBBY) - start;
696 retry:
697 runlen = 0;
698 runstart = 0;
699 for (loc = start; loc < end; loc++) {
700 if (bbp[loc] == (char)0xff) {
701 runlen = 0;
702 continue;
703 }
704
705 /* Start of a run, find the number of high clear bits. */
706 if (runlen == 0) {
707 bit = fls(bbp[loc]);
708 runlen = NBBY - bit;
709 runstart = loc * NBBY + bit;
710 } else if (bbp[loc] == 0) {
711 /* Continue a run. */
712 runlen += NBBY;
713 } else {
714 /*
715 * Finish the current run. If it isn't long
716 * enough, start a new one.
717 */
718 bit = ffs(bbp[loc]) - 1;
719 runlen += bit;
720 if (runlen >= 8) {
721 bno = runstart;
722 goto gotit;
723 }
724
725 /* Run was too short, start a new one. */
726 bit = fls(bbp[loc]);
727 runlen = NBBY - bit;
728 runstart = loc * NBBY + bit;
729 }
730
731 /* If the current run is long enough, use it. */
732 if (runlen >= 8) {
733 bno = runstart;
734 goto gotit;
735 }
736 }
737 if (start != 0) {
738 end = start;
739 start = 0;
740 goto retry;
741 }
742
743 bno = ext2_mapsearch(fs, bbp, bpref);
744 if (bno < 0){
745 brelse(bp);
746 EXT2_LOCK(ump);
747 return (0);
748 }
749 gotit:
750 #ifdef INVARIANTS
751 if (isset(bbp, bno)) {
752 printf("ext2fs_alloccgblk: cg=%d bno=%jd fs=%s\n",
753 cg, (intmax_t)bno, fs->e2fs_fsmnt);
754 panic("ext2fs_alloccg: dup alloc");
755 }
756 #endif
757 setbit(bbp, bno);
758 EXT2_LOCK(ump);
759 ext2_clusteracct(fs, bbp, cg, bno, -1);
760 fs->e2fs->e2fs_fbcount--;
761 fs->e2fs_gd[cg].ext2bgd_nbfree--;
762 fs->e2fs_fmod = 1;
763 EXT2_UNLOCK(ump);
764 bdwrite(bp);
765 return (cg * fs->e2fs->e2fs_fpg + fs->e2fs->e2fs_first_dblock + bno);
766 }
767
768 /*
769 * Determine whether a cluster can be allocated.
770 */
771 static daddr_t
772 ext2_clusteralloc(struct inode *ip, int cg, daddr_t bpref, int len)
773 {
774 struct m_ext2fs *fs;
775 struct ext2mount *ump;
776 struct buf *bp;
777 char *bbp;
778 int bit, error, got, i, loc, run;
779 int32_t *lp;
780 daddr_t bno;
781
782 fs = ip->i_e2fs;
783 ump = ip->i_ump;
784
785 if (fs->e2fs_maxcluster[cg] < len)
786 return (0);
787
788 EXT2_UNLOCK(ump);
789 error = bread(ip->i_devvp,
790 fsbtodb(fs, fs->e2fs_gd[cg].ext2bgd_b_bitmap),
791 (int)fs->e2fs_bsize, NOCRED, &bp);
792 if (error)
793 goto fail_lock;
794
795 bbp = (char *)bp->b_data;
796 EXT2_LOCK(ump);
797 /*
798 * Check to see if a cluster of the needed size (or bigger) is
799 * available in this cylinder group.
800 */
801 lp = &fs->e2fs_clustersum[cg].cs_sum[len];
802 for (i = len; i <= fs->e2fs_contigsumsize; i++)
803 if (*lp++ > 0)
804 break;
805 if (i > fs->e2fs_contigsumsize) {
806 /*
807 * Update the cluster summary information to reflect
808 * the true maximum-sized cluster so that future cluster
809 * allocation requests can avoid reading the bitmap only
810 * to find no cluster.
811 */
812 lp = &fs->e2fs_clustersum[cg].cs_sum[len - 1];
813 for (i = len - 1; i > 0; i--)
814 if (*lp-- > 0)
815 break;
816 fs->e2fs_maxcluster[cg] = i;
817 goto fail;
818 }
819 EXT2_UNLOCK(ump);
820
821 /* Search the bitmap to find a big enough cluster like in FFS. */
822 if (dtog(fs, bpref) != cg)
823 bpref = 0;
824 if (bpref != 0)
825 bpref = dtogd(fs, bpref);
826 loc = bpref / NBBY;
827 bit = 1 << (bpref % NBBY);
828 for (run = 0, got = bpref; got < fs->e2fs->e2fs_fpg; got++) {
829 if ((bbp[loc] & bit) != 0)
830 run = 0;
831 else {
832 run++;
833 if (run == len)
834 break;
835 }
836 if ((got & (NBBY - 1)) != (NBBY - 1))
837 bit <<= 1;
838 else {
839 loc++;
840 bit = 1;
841 }
842 }
843
844 if (got >= fs->e2fs->e2fs_fpg)
845 goto fail_lock;
846
847 /* Allocate the cluster that we found. */
848 for (i = 1; i < len; i++)
849 if (!isclr(bbp, got - run + i))
850 panic("ext2_clusteralloc: map mismatch");
851
852 bno = got - run + 1;
853 if (bno >= fs->e2fs->e2fs_fpg)
854 panic("ext2_clusteralloc: allocated out of group");
855
856 EXT2_LOCK(ump);
857 for (i = 0; i < len; i += fs->e2fs_fpb) {
858 setbit(bbp, bno + i);
859 ext2_clusteracct(fs, bbp, cg, bno + i, -1);
860 fs->e2fs->e2fs_fbcount--;
861 fs->e2fs_gd[cg].ext2bgd_nbfree--;
862 }
863 fs->e2fs_fmod = 1;
864 EXT2_UNLOCK(ump);
865
866 bdwrite(bp);
867 return (cg * fs->e2fs->e2fs_fpg + fs->e2fs->e2fs_first_dblock + bno);
868
869 fail_lock:
870 EXT2_LOCK(ump);
871 fail:
872 brelse(bp);
873 return (0);
874 }
875
876 /*
877 * Determine whether an inode can be allocated.
878 *
879 * Check to see if an inode is available, and if it is,
880 * allocate it using tode in the specified cylinder group.
881 */
882 static daddr_t
883 ext2_nodealloccg(struct inode *ip, int cg, daddr_t ipref, int mode)
884 {
885 struct m_ext2fs *fs;
886 struct buf *bp;
887 struct ext2mount *ump;
888 int error, start, len;
889 char *ibp, *loc;
890 ipref--; /* to avoid a lot of (ipref -1) */
891 if (ipref == -1)
892 ipref = 0;
893 fs = ip->i_e2fs;
894 ump = ip->i_ump;
895 if (fs->e2fs_gd[cg].ext2bgd_nifree == 0)
896 return (0);
897 EXT2_UNLOCK(ump);
898 error = bread(ip->i_devvp, fsbtodb(fs,
899 fs->e2fs_gd[cg].ext2bgd_i_bitmap),
900 (int)fs->e2fs_bsize, NOCRED, &bp);
901 if (error) {
902 brelse(bp);
903 EXT2_LOCK(ump);
904 return (0);
905 }
906 if (fs->e2fs_gd[cg].ext2bgd_nifree == 0) {
907 /*
908 * Another thread allocated the last i-node in this
909 * group while we were waiting for the buffer.
910 */
911 brelse(bp);
912 EXT2_LOCK(ump);
913 return (0);
914 }
915 ibp = (char *)bp->b_data;
916 if (ipref) {
917 ipref %= fs->e2fs->e2fs_ipg;
918 if (isclr(ibp, ipref))
919 goto gotit;
920 }
921 start = ipref / NBBY;
922 len = howmany(fs->e2fs->e2fs_ipg - ipref, NBBY);
923 loc = memcchr(&ibp[start], 0xff, len);
924 if (loc == NULL) {
925 len = start + 1;
926 start = 0;
927 loc = memcchr(&ibp[start], 0xff, len);
928 if (loc == NULL) {
929 printf("cg = %d, ipref = %lld, fs = %s\n",
930 cg, (long long)ipref, fs->e2fs_fsmnt);
931 panic("ext2fs_nodealloccg: map corrupted");
932 /* NOTREACHED */
933 }
934 }
935 ipref = (loc - ibp) * NBBY + ffs(~*loc) - 1;
936 gotit:
937 setbit(ibp, ipref);
938 EXT2_LOCK(ump);
939 fs->e2fs_gd[cg].ext2bgd_nifree--;
940 fs->e2fs->e2fs_ficount--;
941 fs->e2fs_fmod = 1;
942 if ((mode & IFMT) == IFDIR) {
943 fs->e2fs_gd[cg].ext2bgd_ndirs++;
944 fs->e2fs_total_dir++;
945 }
946 EXT2_UNLOCK(ump);
947 bdwrite(bp);
948 return (cg * fs->e2fs->e2fs_ipg + ipref +1);
949 }
950
951 /*
952 * Free a block or fragment.
953 *
954 */
955 void
956 ext2_blkfree(struct inode *ip, e4fs_daddr_t bno, long size)
957 {
958 struct m_ext2fs *fs;
959 struct buf *bp;
960 struct ext2mount *ump;
961 int cg, error;
962 char *bbp;
963
964 fs = ip->i_e2fs;
965 ump = ip->i_ump;
966 cg = dtog(fs, bno);
967 if ((u_int)bno >= fs->e2fs->e2fs_bcount) {
968 printf("bad block %lld, ino %llu\n", (long long)bno,
969 (unsigned long long)ip->i_number);
970 ext2_fserr(fs, ip->i_uid, "bad block");
971 return;
972 }
973 error = bread(ip->i_devvp,
974 fsbtodb(fs, fs->e2fs_gd[cg].ext2bgd_b_bitmap),
975 (int)fs->e2fs_bsize, NOCRED, &bp);
976 if (error) {
977 brelse(bp);
978 return;
979 }
980 bbp = (char *)bp->b_data;
981 bno = dtogd(fs, bno);
982 if (isclr(bbp, bno)) {
983 printf("block = %lld, fs = %s\n",
984 (long long)bno, fs->e2fs_fsmnt);
985 panic("ext2_blkfree: freeing free block");
986 }
987 clrbit(bbp, bno);
988 EXT2_LOCK(ump);
989 ext2_clusteracct(fs, bbp, cg, bno, 1);
990 fs->e2fs->e2fs_fbcount++;
991 fs->e2fs_gd[cg].ext2bgd_nbfree++;
992 fs->e2fs_fmod = 1;
993 EXT2_UNLOCK(ump);
994 bdwrite(bp);
995 }
996
997 /*
998 * Free an inode.
999 *
1000 */
1001 int
1002 ext2_vfree(struct vnode *pvp, ino_t ino, int mode)
1003 {
1004 struct m_ext2fs *fs;
1005 struct inode *pip;
1006 struct buf *bp;
1007 struct ext2mount *ump;
1008 int error, cg;
1009 char * ibp;
1010
1011 pip = VTOI(pvp);
1012 fs = pip->i_e2fs;
1013 ump = pip->i_ump;
1014 if ((u_int)ino > fs->e2fs_ipg * fs->e2fs_gcount)
1015 panic("ext2_vfree: range: devvp = %p, ino = %ju, fs = %s",
1016 pip->i_devvp, (uintmax_t)ino, fs->e2fs_fsmnt);
1017
1018 cg = ino_to_cg(fs, ino);
1019 error = bread(pip->i_devvp,
1020 fsbtodb(fs, fs->e2fs_gd[cg].ext2bgd_i_bitmap),
1021 (int)fs->e2fs_bsize, NOCRED, &bp);
1022 if (error) {
1023 brelse(bp);
1024 return (0);
1025 }
1026 ibp = (char *)bp->b_data;
1027 ino = (ino - 1) % fs->e2fs->e2fs_ipg;
1028 if (isclr(ibp, ino)) {
1029 printf("ino = %llu, fs = %s\n",
1030 (unsigned long long)ino, fs->e2fs_fsmnt);
1031 if (fs->e2fs_ronly == 0)
1032 panic("ext2_vfree: freeing free inode");
1033 }
1034 clrbit(ibp, ino);
1035 EXT2_LOCK(ump);
1036 fs->e2fs->e2fs_ficount++;
1037 fs->e2fs_gd[cg].ext2bgd_nifree++;
1038 if ((mode & IFMT) == IFDIR) {
1039 fs->e2fs_gd[cg].ext2bgd_ndirs--;
1040 fs->e2fs_total_dir--;
1041 }
1042 fs->e2fs_fmod = 1;
1043 EXT2_UNLOCK(ump);
1044 bdwrite(bp);
1045 return (0);
1046 }
1047
1048 /*
1049 * Find a block in the specified cylinder group.
1050 *
1051 * It is a panic if a request is made to find a block if none are
1052 * available.
1053 */
1054 static daddr_t
1055 ext2_mapsearch(struct m_ext2fs *fs, char *bbp, daddr_t bpref)
1056 {
1057 char *loc;
1058 int start, len;
1059
1060 /*
1061 * find the fragment by searching through the free block
1062 * map for an appropriate bit pattern
1063 */
1064 if (bpref)
1065 start = dtogd(fs, bpref) / NBBY;
1066 else
1067 start = 0;
1068 len = howmany(fs->e2fs->e2fs_fpg, NBBY) - start;
1069 loc = memcchr(&bbp[start], 0xff, len);
1070 if (loc == NULL) {
1071 len = start + 1;
1072 start = 0;
1073 loc = memcchr(&bbp[start], 0xff, len);
1074 if (loc == NULL) {
1075 printf("start = %d, len = %d, fs = %s\n",
1076 start, len, fs->e2fs_fsmnt);
1077 panic("ext2_mapsearch: map corrupted");
1078 /* NOTREACHED */
1079 }
1080 }
1081 return ((loc - bbp) * NBBY + ffs(~*loc) - 1);
1082 }
1083
1084 /*
1085 * Fserr prints the name of a filesystem with an error diagnostic.
1086 *
1087 * The form of the error message is:
1088 * fs: error message
1089 */
1090 static void
1091 ext2_fserr(struct m_ext2fs *fs, uid_t uid, char *cp)
1092 {
1093
1094 log(LOG_ERR, "uid %u on %s: %s\n", uid, fs->e2fs_fsmnt, cp);
1095 }
1096
1097 int
1098 cg_has_sb(int i)
1099 {
1100 int a3, a5, a7;
1101
1102 if (i == 0 || i == 1)
1103 return 1;
1104 for (a3 = 3, a5 = 5, a7 = 7;
1105 a3 <= i || a5 <= i || a7 <= i;
1106 a3 *= 3, a5 *= 5, a7 *= 7)
1107 if (i == a3 || i == a5 || i == a7)
1108 return 1;
1109 return 0;
1110 }
Cache object: f6a25c17f72d72fa63e535adcb1f3564
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