File: /usr/src/linux/fs/hpfs/alloc.c
1 /*
2 * linux/fs/hpfs/alloc.c
3 *
4 * Mikulas Patocka (mikulas@artax.karlin.mff.cuni.cz), 1998-1999
5 *
6 * HPFS bitmap operations
7 */
8
9 #include "hpfs_fn.h"
10
11 /*
12 * Check if a sector is allocated in bitmap
13 * This is really slow. Turned on only if chk==2
14 */
15
16 static int chk_if_allocated(struct super_block *s, secno sec, char *msg)
17 {
18 struct quad_buffer_head qbh;
19 unsigned *bmp;
20 if (!(bmp = hpfs_map_bitmap(s, sec >> 14, &qbh, "chk"))) goto fail;
21 if ((bmp[(sec & 0x3fff) >> 5] >> (sec & 0x1f)) & 1) {
22 hpfs_error(s, "sector '%s' - %08x not allocated in bitmap", msg, sec);
23 goto fail1;
24 }
25 hpfs_brelse4(&qbh);
26 if (sec >= s->s_hpfs_dirband_start && sec < s->s_hpfs_dirband_start + s->s_hpfs_dirband_size) {
27 unsigned ssec = (sec - s->s_hpfs_dirband_start) / 4;
28 if (!(bmp = hpfs_map_dnode_bitmap(s, &qbh))) goto fail;
29 if ((bmp[ssec >> 5] >> (ssec & 0x1f)) & 1) {
30 hpfs_error(s, "sector '%s' - %08x not allocated in directory bitmap", msg, sec);
31 goto fail1;
32 }
33 hpfs_brelse4(&qbh);
34 }
35 return 0;
36 fail1:
37 hpfs_brelse4(&qbh);
38 fail:
39 return 1;
40 }
41
42 /*
43 * Check if sector(s) have proper number and additionally check if they're
44 * allocated in bitmap.
45 */
46
47 int hpfs_chk_sectors(struct super_block *s, secno start, int len, char *msg)
48 {
49 if (start + len < start || start < 0x12 ||
50 start + len > s->s_hpfs_fs_size) {
51 hpfs_error(s, "sector(s) '%s' badly placed at %08x", msg, start);
52 return 1;
53 }
54 if (s->s_hpfs_chk>=2) {
55 int i;
56 for (i = 0; i < len; i++)
57 if (chk_if_allocated(s, start + i, msg)) return 1;
58 }
59 return 0;
60 }
61
62 static secno alloc_in_bmp(struct super_block *s, secno near, unsigned n, unsigned forward)
63 {
64 struct quad_buffer_head qbh;
65 unsigned *bmp;
66 unsigned bs = near & ~0x3fff;
67 unsigned nr = (near & 0x3fff) & ~(n - 1);
68 /*unsigned mnr;*/
69 unsigned i, q;
70 int a, b;
71 secno ret = 0;
72 if (n != 1 && n != 4) {
73 hpfs_error(s, "Bad allocation size: %d", n);
74 return 0;
75 }
76 lock_super(s);
77 if (bs != ~0x3fff) {
78 if (!(bmp = hpfs_map_bitmap(s, near >> 14, &qbh, "aib"))) goto uls;
79 } else {
80 if (!(bmp = hpfs_map_dnode_bitmap(s, &qbh))) goto uls;
81 }
82 /*if (!tstbits(bmp, nr + n, n + forward)) {
83 ret = bs + nr;
84 goto rt;
85 }
86 if (!tstbits(bmp, nr + 2*n, n + forward)) {
87 ret = bs + nr + n;
88 goto rt;
89 }*/
90 q = nr + n; b = 0;
91 while ((a = tstbits(bmp, q, n + forward))) {
92 q += a;
93 if (n != 1) q = ((q-1)&~(n-1))+n;
94 if (!b) {
95 if (q>>5 != nr>>5) {
96 b = 1;
97 q = nr & 0x1f;
98 }
99 } else if (q > nr) break;
100 }
101 if (!a) {
102 ret = bs + q;
103 goto rt;
104 }
105 nr >>= 5;
106 for (i = nr + 1; i != nr; i++, i &= 0x1ff) {
107 if (!bmp[i]) continue;
108 if (n + forward >= 0x3f && bmp[i] != -1) continue;
109 q = i<<5;
110 if (i > 0) {
111 unsigned k = bmp[i-1];
112 while (k & 0x80000000) {
113 q--; k <<= 1;
114 }
115 }
116 if (n != 1) q = ((q-1)&~(n-1))+n;
117 while ((a = tstbits(bmp, q, n + forward))) {
118 q += a;
119 if (n != 1) q = ((q-1)&~(n-1))+n;
120 if (q>>5 > i) break;
121 }
122 if (!a) {
123 ret = bs + q;
124 goto rt;
125 }
126 }
127 rt:
128 if (ret) {
129 if (s->s_hpfs_chk && ((ret >> 14) != (bs >> 14) || (bmp[(ret & 0x3fff) >> 5] | ~(((1 << n) - 1) << (ret & 0x1f))) != 0xffffffff)) {
130 hpfs_error(s, "Allocation doesn't work! Wanted %d, allocated at %08x", n, ret);
131 ret = 0;
132 goto b;
133 }
134 bmp[(ret & 0x3fff) >> 5] &= ~(((1 << n) - 1) << (ret & 0x1f));
135 hpfs_mark_4buffers_dirty(&qbh);
136 }
137 b:
138 hpfs_brelse4(&qbh);
139 uls:
140 unlock_super(s);
141 return ret;
142 }
143
144 /*
145 * Allocation strategy: 1) search place near the sector specified
146 * 2) search bitmap where free sectors last found
147 * 3) search all bitmaps
148 * 4) search all bitmaps ignoring number of pre-allocated
149 * sectors
150 */
151
152 secno hpfs_alloc_sector(struct super_block *s, secno near, unsigned n, int forward, int lock)
153 {
154 secno sec;
155 unsigned i;
156 unsigned n_bmps;
157 int b = s->s_hpfs_c_bitmap;
158 int f_p = 0;
159 if (forward < 0) {
160 forward = -forward;
161 f_p = 1;
162 }
163 if (lock) hpfs_lock_creation(s);
164 if (near && near < s->s_hpfs_fs_size)
165 if ((sec = alloc_in_bmp(s, near, n, f_p ? forward : forward/4))) goto ret;
166 if (b != -1) {
167 if ((sec = alloc_in_bmp(s, b<<14, n, f_p ? forward : forward/2))) {
168 b &= 0x0fffffff;
169 goto ret;
170 }
171 if (b > 0x10000000) if ((sec = alloc_in_bmp(s, (b&0xfffffff)<<14, n, f_p ? forward : 0))) goto ret;
172 }
173 n_bmps = (s->s_hpfs_fs_size + 0x4000 - 1) >> 14;
174 for (i = 0; i < n_bmps / 2; i++) {
175 if ((sec = alloc_in_bmp(s, (n_bmps/2+i) << 14, n, forward))) {
176 s->s_hpfs_c_bitmap = n_bmps/2+i;
177 goto ret;
178 }
179 if ((sec = alloc_in_bmp(s, (n_bmps/2-i-1) << 14, n, forward))) {
180 s->s_hpfs_c_bitmap = n_bmps/2-i-1;
181 goto ret;
182 }
183 }
184 if ((sec = alloc_in_bmp(s, (n_bmps-1) << 14, n, forward))) {
185 s->s_hpfs_c_bitmap = n_bmps-1;
186 goto ret;
187 }
188 if (!f_p) {
189 for (i = 0; i < n_bmps; i++)
190 if ((sec = alloc_in_bmp(s, i << 14, n, 0))) {
191 s->s_hpfs_c_bitmap = 0x10000000 + i;
192 goto ret;
193 }
194 }
195 sec = 0;
196 ret:
197 if (sec && f_p) {
198 for (i = 0; i < forward; i++) {
199 if (!hpfs_alloc_if_possible_nolock(s, sec + i + 1)) {
200 hpfs_error(s, "Prealloc doesn't work! Wanted %d, allocated at %08x, can't allocate %d", forward, sec, i);
201 sec = 0;
202 break;
203 }
204 }
205 }
206 if (lock) hpfs_unlock_creation(s);
207 return sec;
208 }
209
210 static secno alloc_in_dirband(struct super_block *s, secno near, int lock)
211 {
212 unsigned nr = near;
213 secno sec;
214 if (nr < s->s_hpfs_dirband_start)
215 nr = s->s_hpfs_dirband_start;
216 if (nr >= s->s_hpfs_dirband_start + s->s_hpfs_dirband_size)
217 nr = s->s_hpfs_dirband_start + s->s_hpfs_dirband_size - 4;
218 nr -= s->s_hpfs_dirband_start;
219 nr >>= 2;
220 if (lock) hpfs_lock_creation(s);
221 sec = alloc_in_bmp(s, (~0x3fff) | nr, 1, 0);
222 if (lock) hpfs_unlock_creation(s);
223 if (!sec) return 0;
224 return ((sec & 0x3fff) << 2) + s->s_hpfs_dirband_start;
225 }
226
227 /* Alloc sector if it's free */
228
229 int hpfs_alloc_if_possible_nolock(struct super_block *s, secno sec)
230 {
231 struct quad_buffer_head qbh;
232 unsigned *bmp;
233 lock_super(s);
234 if (!(bmp = hpfs_map_bitmap(s, sec >> 14, &qbh, "aip"))) goto end;
235 if (bmp[(sec & 0x3fff) >> 5] & (1 << (sec & 0x1f))) {
236 bmp[(sec & 0x3fff) >> 5] &= ~(1 << (sec & 0x1f));
237 hpfs_mark_4buffers_dirty(&qbh);
238 hpfs_brelse4(&qbh);
239 unlock_super(s);
240 return 1;
241 }
242 hpfs_brelse4(&qbh);
243 end:
244 unlock_super(s);
245 return 0;
246 }
247
248 int hpfs_alloc_if_possible(struct super_block *s, secno sec)
249 {
250 int r;
251 hpfs_lock_creation(s);
252 r = hpfs_alloc_if_possible_nolock(s, sec);
253 hpfs_unlock_creation(s);
254 return r;
255 }
256
257 /* Free sectors in bitmaps */
258
259 void hpfs_free_sectors(struct super_block *s, secno sec, unsigned n)
260 {
261 struct quad_buffer_head qbh;
262 unsigned *bmp;
263 /*printk("2 - ");*/
264 if (!n) return;
265 if (sec < 0x12) {
266 hpfs_error(s, "Trying to free reserved sector %08x", sec);
267 return;
268 }
269 lock_super(s);
270 new_map:
271 if (!(bmp = hpfs_map_bitmap(s, sec >> 14, &qbh, "free"))) {
272 unlock_super(s);
273 return;
274 }
275 new_tst:
276 if ((bmp[(sec & 0x3fff) >> 5] >> (sec & 0x1f) & 1)) {
277 hpfs_error(s, "sector %08x not allocated", sec);
278 hpfs_brelse4(&qbh);
279 unlock_super(s);
280 return;
281 }
282 bmp[(sec & 0x3fff) >> 5] |= 1 << (sec & 0x1f);
283 if (!--n) {
284 hpfs_mark_4buffers_dirty(&qbh);
285 hpfs_brelse4(&qbh);
286 unlock_super(s);
287 return;
288 }
289 if (!(++sec & 0x3fff)) {
290 hpfs_mark_4buffers_dirty(&qbh);
291 hpfs_brelse4(&qbh);
292 goto new_map;
293 }
294 goto new_tst;
295 }
296
297 /*
298 * Check if there are at least n free dnodes on the filesystem.
299 * Called before adding to dnode. If we run out of space while
300 * splitting dnodes, it would corrupt dnode tree.
301 */
302
303 int hpfs_check_free_dnodes(struct super_block *s, int n)
304 {
305 int n_bmps = (s->s_hpfs_fs_size + 0x4000 - 1) >> 14;
306 int b = s->s_hpfs_c_bitmap & 0x0fffffff;
307 int i, j;
308 unsigned *bmp;
309 struct quad_buffer_head qbh;
310 if ((bmp = hpfs_map_dnode_bitmap(s, &qbh))) {
311 for (j = 0; j < 512; j++) {
312 unsigned k;
313 if (!bmp[j]) continue;
314 for (k = bmp[j]; k; k >>= 1) if (k & 1) if (!--n) {
315 hpfs_brelse4(&qbh);
316 return 0;
317 }
318 }
319 }
320 hpfs_brelse4(&qbh);
321 i = 0;
322 if (s->s_hpfs_c_bitmap != -1 ) {
323 bmp = hpfs_map_bitmap(s, b, &qbh, "chkdn1");
324 goto chk_bmp;
325 }
326 chk_next:
327 if (i == b) i++;
328 if (i >= n_bmps) return 1;
329 bmp = hpfs_map_bitmap(s, i, &qbh, "chkdn2");
330 chk_bmp:
331 if (bmp) {
332 for (j = 0; j < 512; j++) {
333 unsigned k;
334 if (!bmp[j]) continue;
335 for (k = 0xf; k; k <<= 4)
336 if ((bmp[j] & k) == k) {
337 if (!--n) {
338 hpfs_brelse4(&qbh);
339 return 0;
340 }
341 }
342 }
343 hpfs_brelse4(&qbh);
344 }
345 i++;
346 goto chk_next;
347 }
348
349 void hpfs_free_dnode(struct super_block *s, dnode_secno dno)
350 {
351 if (s->s_hpfs_chk) if (dno & 3) {
352 hpfs_error(s, "hpfs_free_dnode: dnode %08x not aligned", dno);
353 return;
354 }
355 if (dno < s->s_hpfs_dirband_start ||
356 dno >= s->s_hpfs_dirband_start + s->s_hpfs_dirband_size) {
357 hpfs_free_sectors(s, dno, 4);
358 } else {
359 struct quad_buffer_head qbh;
360 unsigned *bmp;
361 unsigned ssec = (dno - s->s_hpfs_dirband_start) / 4;
362 lock_super(s);
363 if (!(bmp = hpfs_map_dnode_bitmap(s, &qbh))) {
364 unlock_super(s);
365 return;
366 }
367 bmp[ssec >> 5] |= 1 << (ssec & 0x1f);
368 hpfs_mark_4buffers_dirty(&qbh);
369 hpfs_brelse4(&qbh);
370 unlock_super(s);
371 }
372 }
373
374 struct dnode *hpfs_alloc_dnode(struct super_block *s, secno near,
375 dnode_secno *dno, struct quad_buffer_head *qbh,
376 int lock)
377 {
378 struct dnode *d;
379 if (hpfs_count_one_bitmap(s, s->s_hpfs_dmap) > FREE_DNODES_ADD) {
380 if (!(*dno = alloc_in_dirband(s, near, lock)))
381 if (!(*dno = hpfs_alloc_sector(s, near, 4, 0, lock))) return NULL;
382 } else {
383 if (!(*dno = hpfs_alloc_sector(s, near, 4, 0, lock)))
384 if (!(*dno = alloc_in_dirband(s, near, lock))) return NULL;
385 }
386 if (!(d = hpfs_get_4sectors(s, *dno, qbh))) {
387 hpfs_free_dnode(s, *dno);
388 return NULL;
389 }
390 memset(d, 0, 2048);
391 d->magic = DNODE_MAGIC;
392 d->first_free = 52;
393 d->dirent[0] = 32;
394 d->dirent[2] = 8;
395 d->dirent[30] = 1;
396 d->dirent[31] = 255;
397 d->self = *dno;
398 return d;
399 }
400
401 struct fnode *hpfs_alloc_fnode(struct super_block *s, secno near, fnode_secno *fno,
402 struct buffer_head **bh)
403 {
404 struct fnode *f;
405 if (!(*fno = hpfs_alloc_sector(s, near, 1, FNODE_ALLOC_FWD, 1))) return NULL;
406 if (!(f = hpfs_get_sector(s, *fno, bh))) {
407 hpfs_free_sectors(s, *fno, 1);
408 return NULL;
409 }
410 memset(f, 0, 512);
411 f->magic = FNODE_MAGIC;
412 f->ea_offs = 0xc4;
413 f->btree.n_free_nodes = 8;
414 f->btree.first_free = 8;
415 return f;
416 }
417
418 struct anode *hpfs_alloc_anode(struct super_block *s, secno near, anode_secno *ano,
419 struct buffer_head **bh)
420 {
421 struct anode *a;
422 if (!(*ano = hpfs_alloc_sector(s, near, 1, ANODE_ALLOC_FWD, 1))) return NULL;
423 if (!(a = hpfs_get_sector(s, *ano, bh))) {
424 hpfs_free_sectors(s, *ano, 1);
425 return NULL;
426 }
427 memset(a, 0, 512);
428 a->magic = ANODE_MAGIC;
429 a->self = *ano;
430 a->btree.n_free_nodes = 40;
431 a->btree.n_used_nodes = 0;
432 a->btree.first_free = 8;
433 return a;
434 }
435