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Feng Yuning <fengyuning1984@gmail.com>:

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- Fix ntfs reading problem (occurs when trying to load Windows from an NTFS partition, reading always failed).

svn path=/trunk/; revision=28364
This commit is contained in:
Aleksey Bragin 2007-08-15 20:04:50 +00:00
parent 85c976b666
commit 0364357251
1 changed files with 75 additions and 46 deletions
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121
reactos/boot/freeldr/freeldr/fs/ntfs.c
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@ -176,7 +176,7 @@ static ULONGLONG NtfsReadAttribute(PNTFS_ATTR_CONTEXT Context, ULONGLONG Offset,
ULONGLONG CurrentOffset;
ULONGLONG ReadLength;
ULONGLONG AlreadyRead;
if (!Context->Record.IsNonResident)
{
if (Offset > Context->Record.Resident.ValueLength)
@ -186,16 +186,18 @@ static ULONGLONG NtfsReadAttribute(PNTFS_ATTR_CONTEXT Context, ULONGLONG Offset,
RtlCopyMemory(Buffer, (PCHAR)&Context->Record + Context->Record.Resident.ValueOffset + Offset, Length);
return Length;
}
/*
* Non-resident attribute
*/
/*
* I. Find the corresponding start data run.
*/
if (Context->CacheRunOffset == Offset)
AlreadyRead = 0;
if(Context->CacheRunOffset <= Offset && Offset < Context->CacheRunOffset + Context->CacheRunLength * NtfsClusterSize)
{
DataRun = Context->CacheRun;
LastLCN = Context->CacheRunLastLCN;
@ -208,7 +210,7 @@ static ULONGLONG NtfsReadAttribute(PNTFS_ATTR_CONTEXT Context, ULONGLONG Offset,
LastLCN = 0;
DataRun = (PUCHAR)&Context->Record + Context->Record.NonResident.MappingPairsOffset;
CurrentOffset = 0;
while (1)
{
DataRun = NtfsDecodeRun(DataRun, &DataRunOffset, &DataRunLength);
@ -223,70 +225,97 @@ static ULONGLONG NtfsReadAttribute(PNTFS_ATTR_CONTEXT Context, ULONGLONG Offset,
/* Sparse data run. */
DataRunStartLCN = -1;
}
if (Offset >= CurrentOffset &&
Offset < CurrentOffset + (DataRunLength * NtfsClusterSize))
{
break;
}
if (*DataRun == 0)
{
return 0;
return AlreadyRead;
}
CurrentOffset += DataRunLength * NtfsClusterSize;
}
}
/*
* II. Go through the run list and read the data
*/
AlreadyRead = 0;
while (Length > 0)
ReadLength = min(DataRunLength * NtfsClusterSize - (Offset - CurrentOffset), Length);
if (DataRunStartLCN == -1)
RtlZeroMemory(Buffer, ReadLength);
if (NtfsDiskRead(DataRunStartLCN * NtfsClusterSize + Offset - CurrentOffset, ReadLength, Buffer))
{
ReadLength = min(DataRunLength * NtfsClusterSize, Length);
if (DataRunStartLCN == -1)
RtlZeroMemory(Buffer, ReadLength);
else if (!NtfsDiskRead(DataRunStartLCN * NtfsClusterSize + Offset - CurrentOffset, ReadLength, Buffer))
break;
Length -= ReadLength;
Buffer += ReadLength;
AlreadyRead += ReadLength;
/* We finished this request, but there still data in this data run. */
if (Length == 0 && ReadLength != DataRunLength * NtfsClusterSize)
break;
/*
* Go to next run in the list.
*/
if (*DataRun == 0)
break;
DataRun = NtfsDecodeRun(DataRun, &DataRunOffset, &DataRunLength);
if (DataRunOffset != -1)
Length -= ReadLength;
Buffer += ReadLength;
AlreadyRead += ReadLength;
if (ReadLength == DataRunLength * NtfsClusterSize - (Offset - CurrentOffset))
{
/* Normal data run. */
DataRunStartLCN = LastLCN + DataRunOffset;
LastLCN = DataRunStartLCN;
CurrentOffset += DataRunLength * NtfsClusterSize;
DataRun = NtfsDecodeRun(DataRun, &DataRunOffset, &DataRunLength);
if (DataRunLength != -1)
{
DataRunStartLCN = LastLCN + DataRunOffset;
LastLCN = DataRunStartLCN;
}
else
DataRunStartLCN = -1;
if (*DataRun == 0)
return AlreadyRead;
}
else
while (Length > 0)
{
/* Sparse data run. */
DataRunStartLCN = -1;
}
CurrentOffset += DataRunLength * NtfsClusterSize;
}
ReadLength = min(DataRunLength * NtfsClusterSize, Length);
if (DataRunStartLCN == -1)
RtlZeroMemory(Buffer, ReadLength);
else if (!NtfsDiskRead(DataRunStartLCN * NtfsClusterSize, ReadLength, Buffer))
break;
Length -= ReadLength;
Buffer += ReadLength;
AlreadyRead += ReadLength;
/* We finished this request, but there still data in this data run. */
if (Length == 0 && ReadLength != DataRunLength * NtfsClusterSize)
break;
/*
* Go to next run in the list.
*/
if (*DataRun == 0)
break;
CurrentOffset += DataRunLength * NtfsClusterSize;
DataRun = NtfsDecodeRun(DataRun, &DataRunOffset, &DataRunLength);
if (DataRunOffset != -1)
{
/* Normal data run. */
DataRunStartLCN = LastLCN + DataRunOffset;
LastLCN = DataRunStartLCN;
}
else
{
/* Sparse data run. */
DataRunStartLCN = -1;
}
} /* while */
} /* if Disk */
Context->CacheRun = DataRun;
Context->CacheRunOffset = Offset + AlreadyRead;
Context->CacheRunStartLCN = DataRunStartLCN;
Context->CacheRunLength = DataRunLength;
Context->CacheRunLastLCN = LastLCN;
Context->CacheRunCurrentOffset = CurrentOffset;
return AlreadyRead;
}