457 lines
11 KiB
C
457 lines
11 KiB
C
/*
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* linux/fs/hpfs/alloc.c
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*
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* Mikulas Patocka (mikulas@artax.karlin.mff.cuni.cz), 1998-1999
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*
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* HPFS bitmap operations
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*/
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#include "hpfs_fn.h"
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static int hpfs_alloc_if_possible_nolock(struct super_block *s, secno sec);
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/*
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* Check if a sector is allocated in bitmap
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* This is really slow. Turned on only if chk==2
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*/
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static int chk_if_allocated(struct super_block *s, secno sec, char *msg)
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{
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struct quad_buffer_head qbh;
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unsigned *bmp;
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if (!(bmp = hpfs_map_bitmap(s, sec >> 14, &qbh, "chk"))) goto fail;
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if ((bmp[(sec & 0x3fff) >> 5] >> (sec & 0x1f)) & 1) {
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hpfs_error(s, "sector '%s' - %08x not allocated in bitmap", msg, sec);
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goto fail1;
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}
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hpfs_brelse4(&qbh);
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if (sec >= hpfs_sb(s)->sb_dirband_start && sec < hpfs_sb(s)->sb_dirband_start + hpfs_sb(s)->sb_dirband_size) {
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unsigned ssec = (sec - hpfs_sb(s)->sb_dirband_start) / 4;
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if (!(bmp = hpfs_map_dnode_bitmap(s, &qbh))) goto fail;
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if ((bmp[ssec >> 5] >> (ssec & 0x1f)) & 1) {
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hpfs_error(s, "sector '%s' - %08x not allocated in directory bitmap", msg, sec);
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goto fail1;
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}
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hpfs_brelse4(&qbh);
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}
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return 0;
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fail1:
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hpfs_brelse4(&qbh);
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fail:
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return 1;
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}
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/*
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* Check if sector(s) have proper number and additionally check if they're
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* allocated in bitmap.
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*/
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int hpfs_chk_sectors(struct super_block *s, secno start, int len, char *msg)
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{
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if (start + len < start || start < 0x12 ||
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start + len > hpfs_sb(s)->sb_fs_size) {
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hpfs_error(s, "sector(s) '%s' badly placed at %08x", msg, start);
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return 1;
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}
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if (hpfs_sb(s)->sb_chk>=2) {
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int i;
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for (i = 0; i < len; i++)
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if (chk_if_allocated(s, start + i, msg)) return 1;
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}
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return 0;
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}
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static secno alloc_in_bmp(struct super_block *s, secno near, unsigned n, unsigned forward)
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{
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struct quad_buffer_head qbh;
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unsigned *bmp;
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unsigned bs = near & ~0x3fff;
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unsigned nr = (near & 0x3fff) & ~(n - 1);
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/*unsigned mnr;*/
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unsigned i, q;
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int a, b;
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secno ret = 0;
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if (n != 1 && n != 4) {
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hpfs_error(s, "Bad allocation size: %d", n);
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return 0;
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}
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lock_super(s);
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if (bs != ~0x3fff) {
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if (!(bmp = hpfs_map_bitmap(s, near >> 14, &qbh, "aib"))) goto uls;
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} else {
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if (!(bmp = hpfs_map_dnode_bitmap(s, &qbh))) goto uls;
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}
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if (!tstbits(bmp, nr, n + forward)) {
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ret = bs + nr;
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goto rt;
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}
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/*if (!tstbits(bmp, nr + n, n + forward)) {
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ret = bs + nr + n;
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goto rt;
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}*/
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q = nr + n; b = 0;
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while ((a = tstbits(bmp, q, n + forward)) != 0) {
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q += a;
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if (n != 1) q = ((q-1)&~(n-1))+n;
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if (!b) {
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if (q>>5 != nr>>5) {
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b = 1;
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q = nr & 0x1f;
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}
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} else if (q > nr) break;
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}
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if (!a) {
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ret = bs + q;
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goto rt;
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}
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nr >>= 5;
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/*for (i = nr + 1; i != nr; i++, i &= 0x1ff) {*/
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i = nr;
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do {
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if (!bmp[i]) goto cont;
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if (n + forward >= 0x3f && bmp[i] != -1) goto cont;
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q = i<<5;
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if (i > 0) {
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unsigned k = bmp[i-1];
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while (k & 0x80000000) {
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q--; k <<= 1;
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}
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}
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if (n != 1) q = ((q-1)&~(n-1))+n;
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while ((a = tstbits(bmp, q, n + forward)) != 0) {
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q += a;
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if (n != 1) q = ((q-1)&~(n-1))+n;
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if (q>>5 > i) break;
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}
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if (!a) {
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ret = bs + q;
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goto rt;
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}
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cont:
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i++, i &= 0x1ff;
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} while (i != nr);
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rt:
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if (ret) {
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if (hpfs_sb(s)->sb_chk && ((ret >> 14) != (bs >> 14) || (bmp[(ret & 0x3fff) >> 5] | ~(((1 << n) - 1) << (ret & 0x1f))) != 0xffffffff)) {
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hpfs_error(s, "Allocation doesn't work! Wanted %d, allocated at %08x", n, ret);
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ret = 0;
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goto b;
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}
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bmp[(ret & 0x3fff) >> 5] &= ~(((1 << n) - 1) << (ret & 0x1f));
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hpfs_mark_4buffers_dirty(&qbh);
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}
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b:
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hpfs_brelse4(&qbh);
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uls:
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unlock_super(s);
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return ret;
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}
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/*
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* Allocation strategy: 1) search place near the sector specified
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* 2) search bitmap where free sectors last found
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* 3) search all bitmaps
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* 4) search all bitmaps ignoring number of pre-allocated
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* sectors
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*/
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secno hpfs_alloc_sector(struct super_block *s, secno near, unsigned n, int forward, int lock)
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{
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secno sec;
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int i;
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unsigned n_bmps;
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struct hpfs_sb_info *sbi = hpfs_sb(s);
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int f_p = 0;
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int near_bmp;
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if (forward < 0) {
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forward = -forward;
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f_p = 1;
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}
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if (lock) hpfs_lock_creation(s);
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n_bmps = (sbi->sb_fs_size + 0x4000 - 1) >> 14;
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if (near && near < sbi->sb_fs_size) {
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if ((sec = alloc_in_bmp(s, near, n, f_p ? forward : forward/4))) goto ret;
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near_bmp = near >> 14;
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} else near_bmp = n_bmps / 2;
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/*
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if (b != -1) {
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if ((sec = alloc_in_bmp(s, b<<14, n, f_p ? forward : forward/2))) {
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b &= 0x0fffffff;
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goto ret;
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}
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if (b > 0x10000000) if ((sec = alloc_in_bmp(s, (b&0xfffffff)<<14, n, f_p ? forward : 0))) goto ret;
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*/
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if (!f_p) if (forward > sbi->sb_max_fwd_alloc) forward = sbi->sb_max_fwd_alloc;
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less_fwd:
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for (i = 0; i < n_bmps; i++) {
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if (near_bmp+i < n_bmps && ((sec = alloc_in_bmp(s, (near_bmp+i) << 14, n, forward)))) {
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sbi->sb_c_bitmap = near_bmp+i;
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goto ret;
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}
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if (!forward) {
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if (near_bmp-i-1 >= 0 && ((sec = alloc_in_bmp(s, (near_bmp-i-1) << 14, n, forward)))) {
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sbi->sb_c_bitmap = near_bmp-i-1;
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goto ret;
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}
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} else {
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if (near_bmp+i >= n_bmps && ((sec = alloc_in_bmp(s, (near_bmp+i-n_bmps) << 14, n, forward)))) {
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sbi->sb_c_bitmap = near_bmp+i-n_bmps;
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goto ret;
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}
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}
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if (i == 1 && sbi->sb_c_bitmap != -1 && ((sec = alloc_in_bmp(s, (sbi->sb_c_bitmap) << 14, n, forward)))) {
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goto ret;
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}
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}
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if (!f_p) {
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if (forward) {
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sbi->sb_max_fwd_alloc = forward * 3 / 4;
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forward /= 2;
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goto less_fwd;
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}
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}
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sec = 0;
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ret:
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if (sec && f_p) {
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for (i = 0; i < forward; i++) {
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if (!hpfs_alloc_if_possible_nolock(s, sec + i + 1)) {
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hpfs_error(s, "Prealloc doesn't work! Wanted %d, allocated at %08x, can't allocate %d", forward, sec, i);
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sec = 0;
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break;
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}
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}
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}
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if (lock) hpfs_unlock_creation(s);
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return sec;
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}
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static secno alloc_in_dirband(struct super_block *s, secno near, int lock)
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{
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unsigned nr = near;
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secno sec;
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struct hpfs_sb_info *sbi = hpfs_sb(s);
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if (nr < sbi->sb_dirband_start)
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nr = sbi->sb_dirband_start;
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if (nr >= sbi->sb_dirband_start + sbi->sb_dirband_size)
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nr = sbi->sb_dirband_start + sbi->sb_dirband_size - 4;
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nr -= sbi->sb_dirband_start;
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nr >>= 2;
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if (lock) hpfs_lock_creation(s);
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sec = alloc_in_bmp(s, (~0x3fff) | nr, 1, 0);
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if (lock) hpfs_unlock_creation(s);
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if (!sec) return 0;
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return ((sec & 0x3fff) << 2) + sbi->sb_dirband_start;
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}
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/* Alloc sector if it's free */
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static int hpfs_alloc_if_possible_nolock(struct super_block *s, secno sec)
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{
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struct quad_buffer_head qbh;
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unsigned *bmp;
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lock_super(s);
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if (!(bmp = hpfs_map_bitmap(s, sec >> 14, &qbh, "aip"))) goto end;
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if (bmp[(sec & 0x3fff) >> 5] & (1 << (sec & 0x1f))) {
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bmp[(sec & 0x3fff) >> 5] &= ~(1 << (sec & 0x1f));
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hpfs_mark_4buffers_dirty(&qbh);
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hpfs_brelse4(&qbh);
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unlock_super(s);
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return 1;
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}
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hpfs_brelse4(&qbh);
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end:
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unlock_super(s);
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return 0;
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}
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int hpfs_alloc_if_possible(struct super_block *s, secno sec)
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{
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int r;
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hpfs_lock_creation(s);
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r = hpfs_alloc_if_possible_nolock(s, sec);
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hpfs_unlock_creation(s);
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return r;
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}
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/* Free sectors in bitmaps */
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void hpfs_free_sectors(struct super_block *s, secno sec, unsigned n)
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{
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struct quad_buffer_head qbh;
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unsigned *bmp;
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struct hpfs_sb_info *sbi = hpfs_sb(s);
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/*printk("2 - ");*/
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if (!n) return;
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if (sec < 0x12) {
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hpfs_error(s, "Trying to free reserved sector %08x", sec);
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return;
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}
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lock_super(s);
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sbi->sb_max_fwd_alloc += n > 0xffff ? 0xffff : n;
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if (sbi->sb_max_fwd_alloc > 0xffffff) sbi->sb_max_fwd_alloc = 0xffffff;
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new_map:
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if (!(bmp = hpfs_map_bitmap(s, sec >> 14, &qbh, "free"))) {
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unlock_super(s);
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return;
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}
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new_tst:
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if ((bmp[(sec & 0x3fff) >> 5] >> (sec & 0x1f) & 1)) {
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hpfs_error(s, "sector %08x not allocated", sec);
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hpfs_brelse4(&qbh);
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unlock_super(s);
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return;
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}
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bmp[(sec & 0x3fff) >> 5] |= 1 << (sec & 0x1f);
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if (!--n) {
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hpfs_mark_4buffers_dirty(&qbh);
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hpfs_brelse4(&qbh);
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unlock_super(s);
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return;
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}
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if (!(++sec & 0x3fff)) {
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hpfs_mark_4buffers_dirty(&qbh);
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hpfs_brelse4(&qbh);
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goto new_map;
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}
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goto new_tst;
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}
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/*
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* Check if there are at least n free dnodes on the filesystem.
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* Called before adding to dnode. If we run out of space while
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* splitting dnodes, it would corrupt dnode tree.
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*/
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int hpfs_check_free_dnodes(struct super_block *s, int n)
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{
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int n_bmps = (hpfs_sb(s)->sb_fs_size + 0x4000 - 1) >> 14;
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int b = hpfs_sb(s)->sb_c_bitmap & 0x0fffffff;
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int i, j;
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unsigned *bmp;
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struct quad_buffer_head qbh;
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if ((bmp = hpfs_map_dnode_bitmap(s, &qbh))) {
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for (j = 0; j < 512; j++) {
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unsigned k;
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if (!bmp[j]) continue;
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for (k = bmp[j]; k; k >>= 1) if (k & 1) if (!--n) {
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hpfs_brelse4(&qbh);
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return 0;
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}
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}
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}
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hpfs_brelse4(&qbh);
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i = 0;
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if (hpfs_sb(s)->sb_c_bitmap != -1) {
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bmp = hpfs_map_bitmap(s, b, &qbh, "chkdn1");
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goto chk_bmp;
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}
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chk_next:
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if (i == b) i++;
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if (i >= n_bmps) return 1;
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bmp = hpfs_map_bitmap(s, i, &qbh, "chkdn2");
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chk_bmp:
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if (bmp) {
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for (j = 0; j < 512; j++) {
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unsigned k;
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if (!bmp[j]) continue;
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for (k = 0xf; k; k <<= 4)
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if ((bmp[j] & k) == k) {
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if (!--n) {
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hpfs_brelse4(&qbh);
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return 0;
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}
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}
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}
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hpfs_brelse4(&qbh);
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}
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i++;
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goto chk_next;
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}
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void hpfs_free_dnode(struct super_block *s, dnode_secno dno)
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{
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if (hpfs_sb(s)->sb_chk) if (dno & 3) {
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hpfs_error(s, "hpfs_free_dnode: dnode %08x not aligned", dno);
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return;
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}
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if (dno < hpfs_sb(s)->sb_dirband_start ||
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dno >= hpfs_sb(s)->sb_dirband_start + hpfs_sb(s)->sb_dirband_size) {
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hpfs_free_sectors(s, dno, 4);
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} else {
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struct quad_buffer_head qbh;
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unsigned *bmp;
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unsigned ssec = (dno - hpfs_sb(s)->sb_dirband_start) / 4;
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lock_super(s);
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if (!(bmp = hpfs_map_dnode_bitmap(s, &qbh))) {
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unlock_super(s);
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return;
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}
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bmp[ssec >> 5] |= 1 << (ssec & 0x1f);
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hpfs_mark_4buffers_dirty(&qbh);
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hpfs_brelse4(&qbh);
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unlock_super(s);
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}
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}
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struct dnode *hpfs_alloc_dnode(struct super_block *s, secno near,
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dnode_secno *dno, struct quad_buffer_head *qbh,
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int lock)
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{
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struct dnode *d;
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if (hpfs_count_one_bitmap(s, hpfs_sb(s)->sb_dmap) > FREE_DNODES_ADD) {
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if (!(*dno = alloc_in_dirband(s, near, lock)))
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if (!(*dno = hpfs_alloc_sector(s, near, 4, 0, lock))) return NULL;
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} else {
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if (!(*dno = hpfs_alloc_sector(s, near, 4, 0, lock)))
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if (!(*dno = alloc_in_dirband(s, near, lock))) return NULL;
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}
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if (!(d = hpfs_get_4sectors(s, *dno, qbh))) {
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hpfs_free_dnode(s, *dno);
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return NULL;
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}
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memset(d, 0, 2048);
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d->magic = DNODE_MAGIC;
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d->first_free = 52;
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d->dirent[0] = 32;
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d->dirent[2] = 8;
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d->dirent[30] = 1;
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d->dirent[31] = 255;
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d->self = *dno;
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return d;
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}
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struct fnode *hpfs_alloc_fnode(struct super_block *s, secno near, fnode_secno *fno,
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struct buffer_head **bh)
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{
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struct fnode *f;
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if (!(*fno = hpfs_alloc_sector(s, near, 1, FNODE_ALLOC_FWD, 1))) return NULL;
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if (!(f = hpfs_get_sector(s, *fno, bh))) {
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hpfs_free_sectors(s, *fno, 1);
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return NULL;
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}
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memset(f, 0, 512);
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f->magic = FNODE_MAGIC;
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f->ea_offs = 0xc4;
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f->btree.n_free_nodes = 8;
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f->btree.first_free = 8;
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return f;
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}
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struct anode *hpfs_alloc_anode(struct super_block *s, secno near, anode_secno *ano,
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struct buffer_head **bh)
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{
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struct anode *a;
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if (!(*ano = hpfs_alloc_sector(s, near, 1, ANODE_ALLOC_FWD, 1))) return NULL;
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if (!(a = hpfs_get_sector(s, *ano, bh))) {
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hpfs_free_sectors(s, *ano, 1);
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return NULL;
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}
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memset(a, 0, 512);
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a->magic = ANODE_MAGIC;
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a->self = *ano;
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a->btree.n_free_nodes = 40;
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a->btree.n_used_nodes = 0;
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a->btree.first_free = 8;
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return a;
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}
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