The 64-bit file ID on NTFS and defragmentation

OSR_Community_User · September 16, 2002, 5:52pm

Does the 64-bit file ID on NTFS survive degragmentation? I know that it does not survive file system restoration (i.e. DR), but I have also seen the suggestion that a file system may not persist the file ID across a defrag.

typedef struct _FILE_ID_FULL_DIR_INFORMATION {
ULONG NextEntryOffset <>;
ULONG FileIndex <>;
LARGE_INTEGER CreationTime <>;
LARGE_INTEGER LastAccessTime <>;
LARGE_INTEGER LastWriteTime <>;
LARGE_INTEGER ChangeTime <>;
LARGE_INTEGER EndOfFile <>;
LARGE_INTEGER AllocationSize <>;
ULONG FileAttributes <>;
ULONG FileNameLength <>;
ULONG EaSize <>;
–> LARGE_INTEGER FileId <>;
WCHAR FileName <>[1];
} FILE_ID_FULL_DIR_INFORMATION, *PFILE_ID_FULL_DIR_INFORMATION;

OSR_Community_User · September 16, 2002, 5:59pm

The file ID is based on a generation number stored in the MFT entry (read inode) for the file and the MFT index (read inode number.) If the MFT is defragmented, then the file ID will change.

-----Original Message-----
From: Tom Hansen [mailto:xxxxx@inflectionsystems.com]
Sent: Monday, September 16, 2002 4:50 PM
To: File Systems Developers
Subject: [ntfsd] The 64-bit file ID on NTFS and defragmentation

Does the 64-bit file ID on NTFS survive degragmentation? I know that it does not survive file system restoration (i.e. DR), but I have also seen the suggestion that a file system may not persist the file ID across a defrag.

typedef struct _FILE_ID_FULL_DIR_INFORMATION {
ULONG NextEntryOffset <>;
ULONG FileIndex <>;
LARGE_INTEGER CreationTime <>;
LARGE_INTEGER LastAccessTime <>;
LARGE_INTEGER LastWriteTime <>;
LARGE_INTEGER ChangeTime <>;
LARGE_INTEGER EndOfFile <>;
LARGE_INTEGER AllocationSize <>;
ULONG FileAttributes <>;
ULONG FileNameLength <>;
ULONG EaSize <>;
–> LARGE_INTEGER FileId <>;
WCHAR FileName <>[1];
} FILE_ID_FULL_DIR_INFORMATION, *PFILE_ID_FULL_DIR_INFORMATION;

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OSR_Community_User · September 16, 2002, 6:01pm

Hmm I should have said if the MFT is internally defragmented, then the file ID will change.

-----Original Message-----
From: Fuller, Rob
Sent: Monday, September 16, 2002 4:56 PM
To: ‘File Systems Developers’
Subject: RE: [ntfsd] The 64-bit file ID on NTFS and defragmentation

The file ID is based on a generation number stored in the MFT entry (read inode) for the file and the MFT index (read inode number.) If the MFT is defragmented, then the file ID will change.

-----Original Message-----
From: Tom Hansen [mailto:xxxxx@inflectionsystems.com]
Sent: Monday, September 16, 2002 4:50 PM
To: File Systems Developers
Subject: [ntfsd] The 64-bit file ID on NTFS and defragmentation

Does the 64-bit file ID on NTFS survive degragmentation? I know that it does not survive file system restoration (i.e. DR), but I have also seen the suggestion that a file system may not persist the file ID across a defrag.

typedef struct _FILE_ID_FULL_DIR_INFORMATION {
ULONG NextEntryOffset <>;
ULONG FileIndex <>;
LARGE_INTEGER CreationTime <>;
LARGE_INTEGER LastAccessTime <>;
LARGE_INTEGER LastWriteTime <>;
LARGE_INTEGER ChangeTime <>;
LARGE_INTEGER EndOfFile <>;
LARGE_INTEGER AllocationSize <>;
ULONG FileAttributes <>;
ULONG FileNameLength <>;
ULONG EaSize <>;
–> LARGE_INTEGER FileId <>;
WCHAR FileName <>[1];
} FILE_ID_FULL_DIR_INFORMATION, *PFILE_ID_FULL_DIR_INFORMATION;

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To unsubscribe send a blank email to %%email.unsub%%

OSR_Community_User · September 16, 2002, 6:04pm

The MFT is still a regular stream. Defragmenting the extents of the MFT
will not change the order of filerecords (index numbers) allocated
within it, and therefore won’t change the file id.

This posting is provided “AS IS” with no warranties, and confers no
rights.

-----Original Message-----
From: Fuller, Rob [mailto:xxxxx@inin.com]
Sent: Monday, September 16, 2002 2:56 PM
To: File Systems Developers
Subject: [ntfsd] RE: The 64-bit file ID on NTFS and defragmentation

The file ID is based on a generation number stored in the MFT entry
(read inode) for the file and the MFT index (read inode number.) If
the MFT is defragmented, then the file ID will change.

-----Original Message-----
From: Tom Hansen [mailto:xxxxx@inflectionsystems.com]
Sent: Monday, September 16, 2002 4:50 PM
To: File Systems Developers
Subject: [ntfsd] The 64-bit file ID on NTFS and defragmentation

Does the 64-bit file ID on NTFS survive degragmentation? I know that it
does not survive file system restoration (i.e. DR), but I have also seen
the suggestion that a file system may not persist the file ID across a
defrag.

typedef struct _FILE_ID_FULL_DIR_INFORMATION {
ULONG NextEntryOffset <>;
ULONG FileIndex <>;
LARGE_INTEGER CreationTime <>;
LARGE_INTEGER LastAccessTime <>;
LARGE_INTEGER LastWriteTime <>;
LARGE_INTEGER ChangeTime <>;
LARGE_INTEGER EndOfFile <>;
LARGE_INTEGER AllocationSize <>;
ULONG FileAttributes <>;
ULONG FileNameLength <>;
ULONG EaSize <>;
–> LARGE_INTEGER FileId <>;
WCHAR FileName <>[1];
} FILE_ID_FULL_DIR_INFORMATION, *PFILE_ID_FULL_DIR_INFORMATION;

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To unsubscribe send a blank email to %%email.unsub%%

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OSR_Community_User · September 16, 2002, 6:14pm

That is not what I meant. What I meant is that if you internally defragment the MFT, then the file ID’s will change. For example, if you have a lot of holes in the MFT from deleted files and you re-locate the records in the MFT to the beginning of the MFT, then the file ID’s will change.

-----Original Message-----
From: Daniel Lovinger [mailto:xxxxx@windows.microsoft.com]
Sent: Monday, September 16, 2002 5:01 PM
To: File Systems Developers
Subject: [ntfsd] RE: The 64-bit file ID on NTFS and defragmentation