alloc.c 11.1 KB
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456
/*
 *  linux/fs/hpfs/alloc.c
 *
 *  Mikulas Patocka (mikulas@artax.karlin.mff.cuni.cz), 1998-1999
 *
 *  HPFS bitmap operations
 */

#include "hpfs_fn.h"

static int hpfs_alloc_if_possible_nolock(struct super_block *s, secno sec);

/*
 * Check if a sector is allocated in bitmap
 * This is really slow. Turned on only if chk==2
 */

static int chk_if_allocated(struct super_block *s, secno sec, char *msg)
{
	struct quad_buffer_head qbh;
	unsigned *bmp;
	if (!(bmp = hpfs_map_bitmap(s, sec >> 14, &qbh, "chk"))) goto fail;
	if ((bmp[(sec & 0x3fff) >> 5] >> (sec & 0x1f)) & 1) {
		hpfs_error(s, "sector '%s' - %08x not allocated in bitmap", msg, sec);
		goto fail1;
	}
	hpfs_brelse4(&qbh);
	if (sec >= hpfs_sb(s)->sb_dirband_start && sec < hpfs_sb(s)->sb_dirband_start + hpfs_sb(s)->sb_dirband_size) {
		unsigned ssec = (sec - hpfs_sb(s)->sb_dirband_start) / 4;
		if (!(bmp = hpfs_map_dnode_bitmap(s, &qbh))) goto fail;
		if ((bmp[ssec >> 5] >> (ssec & 0x1f)) & 1) {
			hpfs_error(s, "sector '%s' - %08x not allocated in directory bitmap", msg, sec);
			goto fail1;
		}
		hpfs_brelse4(&qbh);
	}
	return 0;
	fail1:
	hpfs_brelse4(&qbh);
	fail:
	return 1;
}

/*
 * Check if sector(s) have proper number and additionally check if they're
 * allocated in bitmap.
 */
	
int hpfs_chk_sectors(struct super_block *s, secno start, int len, char *msg)
{
	if (start + len < start || start < 0x12 ||
	    start + len > hpfs_sb(s)->sb_fs_size) {
	    	hpfs_error(s, "sector(s) '%s' badly placed at %08x", msg, start);
		return 1;
	}
	if (hpfs_sb(s)->sb_chk>=2) {
		int i;
		for (i = 0; i < len; i++)
			if (chk_if_allocated(s, start + i, msg)) return 1;
	}
	return 0;
}

static secno alloc_in_bmp(struct super_block *s, secno near, unsigned n, unsigned forward)
{
	struct quad_buffer_head qbh;
	unsigned *bmp;
	unsigned bs = near & ~0x3fff;
	unsigned nr = (near & 0x3fff) & ~(n - 1);
	/*unsigned mnr;*/
	unsigned i, q;
	int a, b;
	secno ret = 0;
	if (n != 1 && n != 4) {
		hpfs_error(s, "Bad allocation size: %d", n);
		return 0;
	}
	lock_super(s);
	if (bs != ~0x3fff) {
		if (!(bmp = hpfs_map_bitmap(s, near >> 14, &qbh, "aib"))) goto uls;
	} else {
		if (!(bmp = hpfs_map_dnode_bitmap(s, &qbh))) goto uls;
	}
	if (!tstbits(bmp, nr, n + forward)) {
		ret = bs + nr;
		goto rt;
	}
	/*if (!tstbits(bmp, nr + n, n + forward)) {
		ret = bs + nr + n;
		goto rt;
	}*/
	q = nr + n; b = 0;
	while ((a = tstbits(bmp, q, n + forward)) != 0) {
		q += a;
		if (n != 1) q = ((q-1)&~(n-1))+n;
		if (!b) {
			if (q>>5 != nr>>5) {
				b = 1;
				q = nr & 0x1f;
			}
		} else if (q > nr) break;
	}
	if (!a) {
		ret = bs + q;
		goto rt;
	}
	nr >>= 5;
	/*for (i = nr + 1; i != nr; i++, i &= 0x1ff) {*/
	i = nr;
	do {
		if (!bmp[i]) goto cont;
		if (n + forward >= 0x3f && bmp[i] != -1) goto cont;
		q = i<<5;
		if (i > 0) {
			unsigned k = bmp[i-1];
			while (k & 0x80000000) {
				q--; k <<= 1;
			}
		}
		if (n != 1) q = ((q-1)&~(n-1))+n;
		while ((a = tstbits(bmp, q, n + forward)) != 0) {
			q += a;
			if (n != 1) q = ((q-1)&~(n-1))+n;
			if (q>>5 > i) break;
		}
		if (!a) {
			ret = bs + q;
			goto rt;
		}
		cont:
		i++, i &= 0x1ff;
	} while (i != nr);
	rt:
	if (ret) {
		if (hpfs_sb(s)->sb_chk && ((ret >> 14) != (bs >> 14) || (bmp[(ret & 0x3fff) >> 5] | ~(((1 << n) - 1) << (ret & 0x1f))) != 0xffffffff)) {
			hpfs_error(s, "Allocation doesn't work! Wanted %d, allocated at %08x", n, ret);
			ret = 0;
			goto b;
		}
		bmp[(ret & 0x3fff) >> 5] &= ~(((1 << n) - 1) << (ret & 0x1f));
		hpfs_mark_4buffers_dirty(&qbh);
	}
	b:
	hpfs_brelse4(&qbh);
	uls:
	unlock_super(s);
	return ret;
}

/*
 * Allocation strategy:	1) search place near the sector specified
 *			2) search bitmap where free sectors last found
 *			3) search all bitmaps
 *			4) search all bitmaps ignoring number of pre-allocated
 *				sectors
 */

secno hpfs_alloc_sector(struct super_block *s, secno near, unsigned n, int forward, int lock)
{
	secno sec;
	int i;
	unsigned n_bmps;
	struct hpfs_sb_info *sbi = hpfs_sb(s);
	int f_p = 0;
	int near_bmp;
	if (forward < 0) {
		forward = -forward;
		f_p = 1;
	}
	if (lock) hpfs_lock_creation(s);
	n_bmps = (sbi->sb_fs_size + 0x4000 - 1) >> 14;
	if (near && near < sbi->sb_fs_size) {
		if ((sec = alloc_in_bmp(s, near, n, f_p ? forward : forward/4))) goto ret;
		near_bmp = near >> 14;
	} else near_bmp = n_bmps / 2;
	/*
	if (b != -1) {
		if ((sec = alloc_in_bmp(s, b<<14, n, f_p ? forward : forward/2))) {
			b &= 0x0fffffff;
			goto ret;
		}
		if (b > 0x10000000) if ((sec = alloc_in_bmp(s, (b&0xfffffff)<<14, n, f_p ? forward : 0))) goto ret;
	*/
	if (!f_p) if (forward > sbi->sb_max_fwd_alloc) forward = sbi->sb_max_fwd_alloc;
	less_fwd:
	for (i = 0; i < n_bmps; i++) {
		if (near_bmp+i < n_bmps && ((sec = alloc_in_bmp(s, (near_bmp+i) << 14, n, forward)))) {
			sbi->sb_c_bitmap = near_bmp+i;
			goto ret;
		}	
		if (!forward) {
			if (near_bmp-i-1 >= 0 && ((sec = alloc_in_bmp(s, (near_bmp-i-1) << 14, n, forward)))) {
				sbi->sb_c_bitmap = near_bmp-i-1;
				goto ret;
			}
		} else {
			if (near_bmp+i >= n_bmps && ((sec = alloc_in_bmp(s, (near_bmp+i-n_bmps) << 14, n, forward)))) {
				sbi->sb_c_bitmap = near_bmp+i-n_bmps;
				goto ret;
			}
		}
		if (i == 1 && sbi->sb_c_bitmap != -1 && ((sec = alloc_in_bmp(s, (sbi->sb_c_bitmap) << 14, n, forward)))) {
			goto ret;
		}
	}
	if (!f_p) {
		if (forward) {
			sbi->sb_max_fwd_alloc = forward * 3 / 4;
			forward /= 2;
			goto less_fwd;
		}
	}
	sec = 0;
	ret:
	if (sec && f_p) {
		for (i = 0; i < forward; i++) {
			if (!hpfs_alloc_if_possible_nolock(s, sec + i + 1)) {
				hpfs_error(s, "Prealloc doesn't work! Wanted %d, allocated at %08x, can't allocate %d", forward, sec, i);
				sec = 0;
				break;
			}
		}
	}
	if (lock) hpfs_unlock_creation(s);
	return sec;
}

static secno alloc_in_dirband(struct super_block *s, secno near, int lock)
{
	unsigned nr = near;
	secno sec;
	struct hpfs_sb_info *sbi = hpfs_sb(s);
	if (nr < sbi->sb_dirband_start)
		nr = sbi->sb_dirband_start;
	if (nr >= sbi->sb_dirband_start + sbi->sb_dirband_size)
		nr = sbi->sb_dirband_start + sbi->sb_dirband_size - 4;
	nr -= sbi->sb_dirband_start;
	nr >>= 2;
	if (lock) hpfs_lock_creation(s);
	sec = alloc_in_bmp(s, (~0x3fff) | nr, 1, 0);
	if (lock) hpfs_unlock_creation(s);
	if (!sec) return 0;
	return ((sec & 0x3fff) << 2) + sbi->sb_dirband_start;
}

/* Alloc sector if it's free */

static int hpfs_alloc_if_possible_nolock(struct super_block *s, secno sec)
{
	struct quad_buffer_head qbh;
	unsigned *bmp;
	lock_super(s);
	if (!(bmp = hpfs_map_bitmap(s, sec >> 14, &qbh, "aip"))) goto end;
	if (bmp[(sec & 0x3fff) >> 5] & (1 << (sec & 0x1f))) {
		bmp[(sec & 0x3fff) >> 5] &= ~(1 << (sec & 0x1f));
		hpfs_mark_4buffers_dirty(&qbh);
		hpfs_brelse4(&qbh);
		unlock_super(s);
		return 1;
	}
	hpfs_brelse4(&qbh);
	end:
	unlock_super(s);
	return 0;
}

int hpfs_alloc_if_possible(struct super_block *s, secno sec)
{
	int r;
	hpfs_lock_creation(s);
	r = hpfs_alloc_if_possible_nolock(s, sec);
	hpfs_unlock_creation(s);
	return r;
}

/* Free sectors in bitmaps */

void hpfs_free_sectors(struct super_block *s, secno sec, unsigned n)
{
	struct quad_buffer_head qbh;
	unsigned *bmp;
	struct hpfs_sb_info *sbi = hpfs_sb(s);
	/*printk("2 - ");*/
	if (!n) return;
	if (sec < 0x12) {
		hpfs_error(s, "Trying to free reserved sector %08x", sec);
		return;
	}
	lock_super(s);
	sbi->sb_max_fwd_alloc += n > 0xffff ? 0xffff : n;
	if (sbi->sb_max_fwd_alloc > 0xffffff) sbi->sb_max_fwd_alloc = 0xffffff;
	new_map:
	if (!(bmp = hpfs_map_bitmap(s, sec >> 14, &qbh, "free"))) {
		unlock_super(s);
		return;
	}	
	new_tst:
	if ((bmp[(sec & 0x3fff) >> 5] >> (sec & 0x1f) & 1)) {
		hpfs_error(s, "sector %08x not allocated", sec);
		hpfs_brelse4(&qbh);
		unlock_super(s);
		return;
	}
	bmp[(sec & 0x3fff) >> 5] |= 1 << (sec & 0x1f);
	if (!--n) {
		hpfs_mark_4buffers_dirty(&qbh);
		hpfs_brelse4(&qbh);
		unlock_super(s);
		return;
	}	
	if (!(++sec & 0x3fff)) {
		hpfs_mark_4buffers_dirty(&qbh);
		hpfs_brelse4(&qbh);
		goto new_map;
	}
	goto new_tst;
}

/*
 * Check if there are at least n free dnodes on the filesystem.
 * Called before adding to dnode. If we run out of space while
 * splitting dnodes, it would corrupt dnode tree.
 */

int hpfs_check_free_dnodes(struct super_block *s, int n)
{
	int n_bmps = (hpfs_sb(s)->sb_fs_size + 0x4000 - 1) >> 14;
	int b = hpfs_sb(s)->sb_c_bitmap & 0x0fffffff;
	int i, j;
	unsigned *bmp;
	struct quad_buffer_head qbh;
	if ((bmp = hpfs_map_dnode_bitmap(s, &qbh))) {
		for (j = 0; j < 512; j++) {
			unsigned k;
			if (!bmp[j]) continue;
			for (k = bmp[j]; k; k >>= 1) if (k & 1) if (!--n) {
				hpfs_brelse4(&qbh);
				return 0;
			}
		}
	}
	hpfs_brelse4(&qbh);
	i = 0;
	if (hpfs_sb(s)->sb_c_bitmap != -1) {
		bmp = hpfs_map_bitmap(s, b, &qbh, "chkdn1");
		goto chk_bmp;
	}
	chk_next:
	if (i == b) i++;
	if (i >= n_bmps) return 1;
	bmp = hpfs_map_bitmap(s, i, &qbh, "chkdn2");
	chk_bmp:
	if (bmp) {
		for (j = 0; j < 512; j++) {
			unsigned k;
			if (!bmp[j]) continue;
			for (k = 0xf; k; k <<= 4)
				if ((bmp[j] & k) == k) {
					if (!--n) {
						hpfs_brelse4(&qbh);
						return 0;
					}
				}
		}
		hpfs_brelse4(&qbh);
	}
	i++;
	goto chk_next;
}

void hpfs_free_dnode(struct super_block *s, dnode_secno dno)
{
	if (hpfs_sb(s)->sb_chk) if (dno & 3) {
		hpfs_error(s, "hpfs_free_dnode: dnode %08x not aligned", dno);
		return;
	}
	if (dno < hpfs_sb(s)->sb_dirband_start ||
	    dno >= hpfs_sb(s)->sb_dirband_start + hpfs_sb(s)->sb_dirband_size) {
		hpfs_free_sectors(s, dno, 4);
	} else {
		struct quad_buffer_head qbh;
		unsigned *bmp;
		unsigned ssec = (dno - hpfs_sb(s)->sb_dirband_start) / 4;
		lock_super(s);
		if (!(bmp = hpfs_map_dnode_bitmap(s, &qbh))) {
			unlock_super(s);
			return;
		}
		bmp[ssec >> 5] |= 1 << (ssec & 0x1f);
		hpfs_mark_4buffers_dirty(&qbh);
		hpfs_brelse4(&qbh);
		unlock_super(s);
	}
}

struct dnode *hpfs_alloc_dnode(struct super_block *s, secno near,
			 dnode_secno *dno, struct quad_buffer_head *qbh,
			 int lock)
{
	struct dnode *d;
	if (hpfs_count_one_bitmap(s, hpfs_sb(s)->sb_dmap) > FREE_DNODES_ADD) {
		if (!(*dno = alloc_in_dirband(s, near, lock)))
			if (!(*dno = hpfs_alloc_sector(s, near, 4, 0, lock))) return NULL;
	} else {
		if (!(*dno = hpfs_alloc_sector(s, near, 4, 0, lock)))
			if (!(*dno = alloc_in_dirband(s, near, lock))) return NULL;
	}
	if (!(d = hpfs_get_4sectors(s, *dno, qbh))) {
		hpfs_free_dnode(s, *dno);
		return NULL;
	}
	memset(d, 0, 2048);
	d->magic = DNODE_MAGIC;
	d->first_free = 52;
	d->dirent[0] = 32;
	d->dirent[2] = 8;
	d->dirent[30] = 1;
	d->dirent[31] = 255;
	d->self = *dno;
	return d;
}

struct fnode *hpfs_alloc_fnode(struct super_block *s, secno near, fnode_secno *fno,
			  struct buffer_head **bh)
{
	struct fnode *f;
	if (!(*fno = hpfs_alloc_sector(s, near, 1, FNODE_ALLOC_FWD, 1))) return NULL;
	if (!(f = hpfs_get_sector(s, *fno, bh))) {
		hpfs_free_sectors(s, *fno, 1);
		return NULL;
	}	
	memset(f, 0, 512);
	f->magic = FNODE_MAGIC;
	f->ea_offs = 0xc4;
	f->btree.n_free_nodes = 8;
	f->btree.first_free = 8;
	return f;
}

struct anode *hpfs_alloc_anode(struct super_block *s, secno near, anode_secno *ano,
			  struct buffer_head **bh)
{
	struct anode *a;
	if (!(*ano = hpfs_alloc_sector(s, near, 1, ANODE_ALLOC_FWD, 1))) return NULL;
	if (!(a = hpfs_get_sector(s, *ano, bh))) {
		hpfs_free_sectors(s, *ano, 1);
		return NULL;
	}
	memset(a, 0, 512);
	a->magic = ANODE_MAGIC;
	a->self = *ano;
	a->btree.n_free_nodes = 40;
	a->btree.n_used_nodes = 0;
	a->btree.first_free = 8;
	return a;
}