.TH NTFS2BTRFS "8" "May 2023" "ntfs2btrfs 20230501" "System Administration"
.SH NAME
ntfs2btrfs \- convert ntfs filesystem to btrfs filesystem
.SH SYNOPSIS
\fBntfs2btrfs\fR [options] \fIdevice\fR
.SH DESCRIPTION
This is a tool which does in-place conversion of Microsoft's NTFS filesystem
to the open-source filesystem Btrfs, much as \fBbtrfs\-convert\fR does for ext2.
.SH OPTIONS
.PP
-c \fI<ALGO>\fR, --compress=\fI<ALGO>\fR
.RS 4
Uses the specified algorithm to recompress files that are compressed on the
NTFS volume; valid choices are \fIzstd\fR, \fIlzo\fR, \fIzlib\fR, or \fInone\fR.
If you don't specify any value, \fIzstd\fR will be used, assuming it's been
compiled in. Note that this will be ignored if you also select --no-datasum (see
below).
.RE
.PP
-h \fI<ALGO>\fR, --hash=\fI<ALGO>\fR
.RS 4
Uses the specified checksumming algorithm; valid choices are \fIcrc32c\fR,
\fIxxhash\fR, \fIsha256\fR, and \fIblake2\fR. The first of these will be used by
default, and should be fine for most purposes.
.RE
.PP
-r, --rollback
.RS 4
Tries to restore the original NTFS filesystem. See \fBROLLBACK\fR below.
.RE
.PP
-d, --no-datasum
.RS 4
Skips calculating checksums for existing data. Don't choose this unless you're
sure it's what you want.
.RE
.SH ROLLBACK
The original filesystem image is saved as \fIimage/ntfs.img\fR as a reflink copy. You
can restore this at any time by using the rollback option, provided that you've
not moved the data by doing a balance. Bear in mind that this restores the volume
to how it was when you did the conversion, meaning that any changes you've made
since will be lost.
.PP
If you decide to keep the conversion, you can remove the \fIimage\fR subvolume at
any point to free up space.
.SH XATTRS
Various bits of NTFS-specific data are stored as Btrfs xattrs, in a manner that
the Windows btrfs driver understands (\fBhttps://github.com/maharmstone/btrfs\fR). Some
should also be understood by tools such as Wine and Samba, but YMMV.
.IP \[bu] 2
The NTFS attribute value is stored as a hex string at \fIuser.DOSATTRIB\fR.
.IP \[bu] 2
The reparse points on directories are stored at \fIuser.reparse\fR. NTFS symlinks should
be converted into POSIX symlinks. The data for other reparse points will be stored as
the contents of the files.
.IP \[bu] 2
The NT security descriptor is stored as \fIsecurity.NTACL\fR.
.IP \[bu] 2
Alternate data streams on files are stored in the \fIuser\fR namespace, e.g. \fI:Zone.Identifier\fR
becomes \fIuser.Zone.Identifier\fR.
.SH SEE ALSO
.BR btrfs (8),
.BR mkfs.btrfs (8).
.SH AUTHOR
Written by Mark Harmstone (\fBmark@harmstone.com\fR).

.SH WEB
.IP https://github.com/maharmstone/ntfs2btrfs