- 根目录:
- fs
- hpfs
- alloc.c
/*
* 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;
u32 *bmp;
if (!(bmp = hpfs_map_bitmap(s, sec >> 14, &qbh, "chk"))) goto fail;
if ((cpu_to_le32(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 ((le32_to_cpu(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;
}
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;
}
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 (!le32_to_cpu(bmp[i])) goto cont;
if (n + forward >= 0x3f && le32_to_cpu(bmp[i]) != 0xffffffff) goto cont;
q = i<<5;
if (i > 0) {
unsigned k = le32_to_cpu(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) || (le32_to_cpu(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] &= cpu_to_le32(~(((1 << n) - 1) << (ret & 0x1f)));
hpfs_mark_4buffers_dirty(&qbh);
}
b:
hpfs_brelse4(&qbh);
uls:
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)
{
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;
}
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(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;
}
}
}
return sec;
}
static secno alloc_in_dirband(struct super_block *s, secno near)
{
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;
sec = alloc_in_bmp(s, (~0x3fff) | nr, 1, 0);
if (!sec) return 0;
return ((sec & 0x3fff) << 2) + sbi->sb_dirband_start;
}
/* Alloc sector if it's free */
int hpfs_alloc_if_possible(struct super_block *s, secno sec)
{
struct quad_buffer_head qbh;
u32 *bmp;
if (!(bmp = hpfs_map_bitmap(s, sec >> 14, &qbh, "aip"))) goto end;
if (le32_to_cpu(bmp[(sec & 0x3fff) >> 5]) & (1 << (sec & 0x1f))) {
bmp[(sec & 0x3fff) >> 5] &= cpu_to_le32(~(1 << (sec & 0x1f)));
hpfs_mark_4buffers_dirty(&qbh);
hpfs_brelse4(&qbh);
return 1;
}
hpfs_brelse4(&qbh);
end:
return 0;
}
/* Free sectors in bitmaps */
void hpfs_free_sectors(struct super_block *s, secno sec, unsigned n)
{
struct quad_buffer_head qbh;
u32 *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;
}
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"))) {
return;
}
new_tst:
if ((le32_to_cpu(bmp[(sec & 0x3fff) >> 5]) >> (sec & 0x1f) & 1)) {
hpfs_error(s, "sector %08x not allocated", sec);
hpfs_brelse4(&qbh);
return;
}
bmp[(sec & 0x3fff) >> 5] |= cpu_to_le32(1 << (sec & 0x1f));
if (!--n) {
hpfs_mark_4buffers_dirty(&qbh);
hpfs_brelse4(&qbh);
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;
u32 *bmp;
struct quad_buffer_head qbh;
if ((bmp = hpfs_map_dnode_bitmap(s, &qbh))) {
for (j = 0; j < 512; j++) {
unsigned k;
if (!le32_to_cpu(bmp[j])) continue;
for (k = le32_to_cpu(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++) {
u32 k;
if (!le32_to_cpu(bmp[j])) continue;
for (k = 0xf; k; k <<= 4)
if ((le32_to_cpu(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;
u32 *bmp;
unsigned ssec = (dno - hpfs_sb(s)->sb_dirband_start) / 4;
if (!(bmp = hpfs_map_dnode_bitmap(s, &qbh))) {
return;
}
bmp[ssec >> 5] |= cpu_to_le32(1 << (ssec & 0x1f));
hpfs_mark_4buffers_dirty(&qbh);
hpfs_brelse4(&qbh);
}
}
struct dnode *hpfs_alloc_dnode(struct super_block *s, secno near,
dnode_secno *dno, struct quad_buffer_head *qbh)
{
struct dnode *d;
if (hpfs_count_one_bitmap(s, hpfs_sb(s)->sb_dmap) > FREE_DNODES_ADD) {
if (!(*dno = alloc_in_dirband(s, near)))
if (!(*dno = hpfs_alloc_sector(s, near, 4, 0))) return NULL;
} else {
if (!(*dno = hpfs_alloc_sector(s, near, 4, 0)))
if (!(*dno = alloc_in_dirband(s, near))) return NULL;
}
if (!(d = hpfs_get_4sectors(s, *dno, qbh))) {
hpfs_free_dnode(s, *dno);
return NULL;
}
memset(d, 0, 2048);
d->magic = cpu_to_le32(DNODE_MAGIC);
d->first_free = cpu_to_le32(52);
d->dirent[0] = 32;
d->dirent[2] = 8;
d->dirent[30] = 1;
d->dirent[31] = 255;
d->self = cpu_to_le32(*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))) return NULL;
if (!(f = hpfs_get_sector(s, *fno, bh))) {
hpfs_free_sectors(s, *fno, 1);
return NULL;
}
memset(f, 0, 512);
f->magic = cpu_to_le32(FNODE_MAGIC);
f->ea_offs = cpu_to_le16(0xc4);
f->btree.n_free_nodes = 8;
f->btree.first_free = cpu_to_le16(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))) return NULL;
if (!(a = hpfs_get_sector(s, *ano, bh))) {
hpfs_free_sectors(s, *ano, 1);
return NULL;
}
memset(a, 0, 512);
a->magic = cpu_to_le32(ANODE_MAGIC);
a->self = cpu_to_le32(*ano);
a->btree.n_free_nodes = 40;
a->btree.n_used_nodes = 0;
a->btree.first_free = cpu_to_le16(8);
return a;
}