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Setup the cluster and mft allocators. 

(Logical change 1.62)
edge.strict_endians
cantab.net!aia21 2002-12-27 17:25:45 +00:00
parent 91597fe050
commit ac10aa7709
1 changed files with 77 additions and 0 deletions
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77
libntfs/volume.c
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@ -371,6 +371,7 @@ error_exit:
*/
ntfs_volume *ntfs_volume_startup(const char *name, unsigned long rwflag)
{
LCN mft_zone_size, mft_lcn;
s64 br;
const char *OK = "OK";
const char *FAILED = "FAILED";
@ -427,6 +428,82 @@ ntfs_volume *ntfs_volume_startup(const char *name, unsigned long rwflag)
free(bs);
bs = NULL;
/*
* We now initialize the cluster allocator.
*
* FIXME: Move this to its own function? (AIA)
*/
// TODO: Make this tunable at mount time. (AIA)
vol->mft_zone_multiplier = 1;
/* Determine the size of the MFT zone. */
mft_zone_size = vol->nr_clusters;
switch (vol->mft_zone_multiplier) { /* % of volume size in clusters */
case 4:
mft_zone_size >>= 1; /* 50% */
break;
case 3:
mft_zone_size = mft_zone_size * 3 >> 3; /* 37.5% */
break;
case 2:
mft_zone_size >>= 2; /* 25% */
break;
/* case 1: */
default:
mft_zone_size >>= 3; /* 12.5% */
break;
}
/* Setup the mft zone. */
vol->mft_zone_start = vol->mft_zone_pos = vol->mft_lcn;
Dprintf("mft_zone_pos = 0x%Lx\n", (long long)vol->mft_zone_pos);
/*
* Calculate the mft_lcn for an unmodified NTFS volume (see mkntfs
* source) and if the actual mft_lcn is in the expected place or even
* further to the front of the volume, extend the mft_zone to cover the
* beginning of the volume as well. This is in order to protect the
* area reserved for the mft bitmap as well within the mft_zone itself.
* On non-standard volumes we don't protect it as the overhead would be
* higher than the speed increase we would get by doing it.
*/
mft_lcn = (8192 + 2 * vol->cluster_size - 1) / vol->cluster_size;
if (mft_lcn * vol->cluster_size < 16 * 1024)
mft_lcn = (16 * 1024 + vol->cluster_size - 1) /
vol->cluster_size;
if (vol->mft_zone_start <= mft_lcn)
vol->mft_zone_start = 0;
Dprintf("mft_zone_start = 0x%Lx\n", (long long)vol->mft_zone_start);
/*
* Need to cap the mft zone on non-standard volumes so that it does
* not point outside the boundaries of the volume. We do this by
* halving the zone size until we are inside the volume.
*/
vol->mft_zone_end = vol->mft_lcn + mft_zone_size;
while (vol->mft_zone_end >= vol->nr_clusters) {
mft_zone_size >>= 1;
vol->mft_zone_end = vol->mft_lcn + mft_zone_size;
}
Dprintf("mft_zone_end = 0x%Lx\n", (long long)vol->mft_zone_end);
/*
* Set the current position within each data zone to the start of the
* respective zone.
*/
vol->data1_zone_pos = vol->mft_zone_end;
Dprintf("data1_zone_pos = 0x%Lx\n", vol->data1_zone_pos);
vol->data2_zone_pos = 0;
Dprintf("data2_zone_pos = 0x%Lx\n", vol->data2_zone_pos);
/* Set the mft data allocation position to mft record 24. */
vol->mft_data_pos = 24;
/*
* The cluster allocator is now fully operational.
*/
/* Need to setup $MFT so we can use the library read functions. */
Dprintf("Loading $MFT... ");
if (ntfs_mft_load(vol) < 0) {