patch-2.3.2 linux/fs/hpfs/alloc.c

• Lines: 426
• Date: Thu May 13 23:48:20 1999
• Orig file: v2.3.1/linux/fs/hpfs/alloc.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.3.1/linux/fs/hpfs/alloc.c linux/fs/hpfs/alloc.c
@@ -0,0 +1,425 @@
+/*
+ *  linux/fs/hpfs/alloc.c
+ *
+ *  Mikulas Patocka (mikulas@artax.karlin.mff.cuni.cz), 1998-1999
+ *
+ *  HPFS bitmap operations
+ */
+
+#include "hpfs_fn.h"
+
+/*
+ * 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 >= s->s_hpfs_dirband_start && sec < s->s_hpfs_dirband_start + s->s_hpfs_dirband_size) {
+		unsigned ssec = (sec - s->s_hpfs_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 > s->s_hpfs_fs_size) {
+	    	hpfs_error(s, "sector(s) '%s' badly placed at %08x", msg, start);
+		return 1;
+	}
+	if (s->s_hpfs_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, n + forward)) {
+		ret = bs + nr;
+		goto rt;
+	}
+	if (!tstbits(bmp, nr + 2*n, n + forward)) {
+		ret = bs + nr + n;
+		goto rt;
+	}*/
+	q = nr + n; b = 0;
+	while ((a = tstbits(bmp, q, n + forward))) {
+		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) {
+		if (!bmp[i]) continue;
+		if (n + forward >= 0x3f && bmp[i] != -1) continue;
+		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))) {
+			q += a;
+			if (n != 1) q = ((q-1)&~(n-1))+n;
+			if (q>>5 > i) break;
+		}
+		if (!a) {
+			ret = bs + q;
+			goto rt;
+		}
+	}
+	rt:
+	if (ret) {
+		if (s->s_hpfs_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;
+	unsigned i;
+	unsigned n_bmps;
+	int b = s->s_hpfs_c_bitmap;
+	int f_p = 0;
+	if (forward < 0) {
+		forward = -forward;
+		f_p = 1;
+	}
+	if (lock) hpfs_lock_creation(s);
+	if (near && near < s->s_hpfs_fs_size)
+		if ((sec = alloc_in_bmp(s, near, n, f_p ? forward : forward/4))) goto ret;
+	if (b != -1) {
+		if (b < 0x10000000) if ((sec = alloc_in_bmp(s, b<<14, n, f_p ? forward : forward/2))) goto ret;
+		else if ((sec = alloc_in_bmp(s, (b&0xfffffff)<<14, n, f_p ? forward : 0))) goto ret;
+	}	
+	n_bmps = (s->s_hpfs_fs_size + 0x4000 - 1) >> 14;
+	for (i = 0; i < n_bmps / 2; i++) {
+		if ((sec = alloc_in_bmp(s, (n_bmps/2+i) << 14, n, forward))) {
+			s->s_hpfs_c_bitmap = n_bmps/2+i;
+			goto ret;
+		}	
+		if ((sec = alloc_in_bmp(s, (n_bmps/2-i-1) << 14, n, forward))) {
+			s->s_hpfs_c_bitmap = n_bmps/2-i-1;
+			goto ret;
+		}
+	}
+	if ((sec = alloc_in_bmp(s, (n_bmps-1) << 14, n, forward))) {
+		s->s_hpfs_c_bitmap = n_bmps-1;
+		goto ret;
+	}
+	if (!f_p) {
+		for (i = 0; i < n_bmps; i++)
+			if ((sec = alloc_in_bmp(s, i << 14, n, 0))) {
+				s->s_hpfs_c_bitmap = 0x10000000 + i;
+				goto ret;
+			}
+	}
+	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;
+	if (nr < s->s_hpfs_dirband_start)
+		nr = s->s_hpfs_dirband_start;
+	if (nr >= s->s_hpfs_dirband_start + s->s_hpfs_dirband_size)
+		nr = s->s_hpfs_dirband_start + s->s_hpfs_dirband_size - 4;
+	nr -= s->s_hpfs_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) + s->s_hpfs_dirband_start;
+}
+
+/* Alloc sector if it's free */
+
+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;
+	/*printk("2 - ");*/
+	if (!n) return;
+	if (sec < 0x12) {
+		hpfs_error(s, "Trying to free reserved sector %08x", sec);
+		return;
+	}
+	lock_super(s);
+	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 = (s->s_hpfs_fs_size + 0x4000 - 1) >> 14;
+	int b = s->s_hpfs_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;
+			for (k = bmp[j]; k; k >>= 1) if (k & 1) if (!--n) {
+				hpfs_brelse4(&qbh);
+				return 0;
+			}
+		}
+	}
+	hpfs_brelse4(&qbh);
+	i = 0;
+	if (s->s_hpfs_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;
+			for (k = 0xf; k; k <<= 4)
+				if ((bmp[j] & k) == k) {
+					/*printk("%08x,%08x\n",j,i);*/
+					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 (s->s_hpfs_chk) if (dno & 3) {
+		hpfs_error(s, "hpfs_free_dnode: dnode %08x not aligned", dno);
+		return;
+	}
+	if (dno < s->s_hpfs_dirband_start ||
+	    dno >= s->s_hpfs_dirband_start + s->s_hpfs_dirband_size) {
+		hpfs_free_sectors(s, dno, 4);
+	} else {
+		struct quad_buffer_head qbh;
+		unsigned *bmp;
+		unsigned ssec = (dno - s->s_hpfs_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 (!(*dno = alloc_in_dirband(s, near, lock)))
+		if (!(*dno = hpfs_alloc_sector(s, near, 4, 0, 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;
+}