[Bug 1958180] [NEW] "not in multiple of 0x10000" chkdsk errors for sparse files

[Boris Gjenero]

Public bug reported:

In Ubuntu 21.10 using ntfs-3g 1:2017.3.23AR.3-3ubuntu5 I can create
sparse files which result in the following messages from Windows 10 21H2
disk scanning:

Stage 1: Examining basic file system structure ...
The allocated length 0x41000 is not in multiple of 0x10000 for attribute
of type 0x80 and instance tag 0x1.

The Windows GUI will say that the drive was scanned successfully with no
errors, and I will need to look in Event Viewer to see this in scanning
output. Repeated scans will not do anything about this issue. To fix the
issue, make a copy of the affected file in Windows and delete the
original.

Attribute of type 0x80 is the data attribute, which tells where the
file's data is stored. Apparently Windows allocates space for sparse
files in multiples of 64 KB (0x10000), and ntfs-3g does not. The message
from disk scanning in Windows fails to tell you what file is involved. I
only found the affected file after seeing that sparse files use 64 KB
chunks, and then searching the file system for sparse files.

I'm attaching a tar file created with the --sparse option. Extracting it
onto NTFS should create a sparse file which triggers this issue. I'm
testing with a partition with 4 KB clusters.

ProblemType: Bug
DistroRelease: Ubuntu 21.10
Package: ntfs-3g 1:2017.3.23AR.3-3ubuntu5
ProcVersionSignature: Ubuntu 5.13.0-25.26-generic 5.13.19
Uname: Linux 5.13.0-25-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.20.11-0ubuntu71
Architecture: amd64
CasperMD5CheckResult: unknown
CurrentDesktop: XFCE
Date: Mon Jan 17 17:22:47 2022
SourcePackage: ntfs-3g
UpgradeStatus: Upgraded to impish on 2021-10-02 (107 days ago)

** Affects: ntfs-3g (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: amd64 apport-bug impish

** Attachment added: "tar contains sparse file which triggers bug"
   https://bugs.launchpad.net/bugs/1958180/+attachment/5554993/+files/1229312_sparse_266240.tar.xz

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https://bugs.launchpad.net/bugs/1958180

Title:
  "not in multiple of 0x10000" chkdsk errors for sparse files

Status in ntfs-3g package in Ubuntu:
  New

Bug description:
  In Ubuntu 21.10 using ntfs-3g 1:2017.3.23AR.3-3ubuntu5 I can create
  sparse files which result in the following messages from Windows 10
  21H2 disk scanning:

  Stage 1: Examining basic file system structure ...
  The allocated length 0x41000 is not in multiple of 0x10000 for attribute
  of type 0x80 and instance tag 0x1.

  The Windows GUI will say that the drive was scanned successfully with
  no errors, and I will need to look in Event Viewer to see this in
  scanning output. Repeated scans will not do anything about this issue.
  To fix the issue, make a copy of the affected file in Windows and
  delete the original.

  Attribute of type 0x80 is the data attribute, which tells where the
  file's data is stored. Apparently Windows allocates space for sparse
  files in multiples of 64 KB (0x10000), and ntfs-3g does not. The
  message from disk scanning in Windows fails to tell you what file is
  involved. I only found the affected file after seeing that sparse
  files use 64 KB chunks, and then searching the file system for sparse
  files.

  I'm attaching a tar file created with the --sparse option. Extracting
  it onto NTFS should create a sparse file which triggers this issue.
  I'm testing with a partition with 4 KB clusters.

  ProblemType: Bug
  DistroRelease: Ubuntu 21.10
  Package: ntfs-3g 1:2017.3.23AR.3-3ubuntu5
  ProcVersionSignature: Ubuntu 5.13.0-25.26-generic 5.13.19
  Uname: Linux 5.13.0-25-generic x86_64
  NonfreeKernelModules: nvidia_modeset nvidia
  ApportVersion: 2.20.11-0ubuntu71
  Architecture: amd64
  CasperMD5CheckResult: unknown
  CurrentDesktop: XFCE
  Date: Mon Jan 17 17:22:47 2022
  SourcePackage: ntfs-3g
  UpgradeStatus: Upgraded to impish on 2021-10-02 (107 days ago)

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