Optionally record the special files (symlinks, fifos, sockets, character
and block devices) using reparse points instead of using Interix representation.
Doing so, the special files are interoperable with Windows Subsystem for
linux (WSL).
Windows traditionally rejected having both EA and reparse data assigned
to a file, but Windows 10 has dropped the constraint and it uses this
condition massively, so do the same. Note that pre-Windows 10 chkdsk.exe
removes the EA' on reparse points, potentially damaging more recent
volumes.
The Windows Subsystem for Linux (WSL) of Windows 10 uses reparse points
to record special files (symlinks, fifos, sockets, char or block devices).
Honor such reparse points with the same meaning as WSL.
The location of the mount point field in the volume attributes was
dependent on compiling options, thus creating an uneasy dependency
for plugins. So relocate the field to be independent on options.
Currently memory allocations are done through ntfs_malloc() and
ntfs_calloc(), but releases are done through free(3). Defining an
ntfs_free() relay facilitates the debugging of memory leaks in
plugins.
When building a symlink to emulate a Windows junction or absolute
symlink, use the mount point recorded in the volume attributes.
This enables the plugins to emulate object as symlinks.
The reparse tag is not quoted in the "unsupported reparse point"
fake symlink shown when a reparse point cannot be processed. The tag
is useful to determine which plugin, if any, is missing.
When filling a hole in a sparse file, the beginning of the runlist
does not need to be updated. However the allocated size is within
the extent holding its beginning and it needs to be updated.
The 'position' argument is only used for the legacy resource fork and is
disallowed for other extended attributes. The name check is placed first
in the functions as this is how macOS behaves (EINVAL is returned if the
attribute is not the resource fork attribute and the position is non-0
even when the attribute does not exist).
In rare situations, removing an entry from an index root while
rebalancing the index tree, its space was not recovered from the index
root, causing chkdsk to complain. Truncate the index root when this
happens.
When the mount option "posix_nlink" is used, the number of links
returned by stat complies with Posix : the legacy 8.3 names are not
taken into account, and the subdirectories are taken into account
for directories. This causes some overhead for recomputing the
number of links.
When a compressed file has been deteriorated through hardware error
or accidental overwriting, some unrelated data could be leaked.
Make sure to zero fill the buffer when this happens.
The translations of Windows paths designed for translating Windows symlinks
and mount points may also be used in plugins for translation execlinks,
so make them available.
The types of reparse point objects cannot be decided upon the data
available in a directory, so we must delegate their determination to a
specific plugin when available, and be consistent if there is none.
Following some change in the Linux kernel, the kernel cacheing of
attributes is not satisfactory (at least the number of hard links is
not refreshed), and has to be disabled.
Since Windows 10, the cluster size may be greater than 128 sectors, and
it has to be recorded as a power of 2 in the boot sector. Hence there
are two possible ways of cluster size. Accept both ways leading to
valid values.
On linux the request argument of ioctl() is defined as an unsigned long,
but the fuse protocol squashes it into a signed int. As a consequence
the value received by ntfs-3g may appear as negative and different from
the value defined by the corresponding macro.
So define the request argument as unsigned long in ntfs-3g. It has
however to be fed as unsigned from fuse until the fuse protocol is
updated.
An earlier patch enabled updating a file proper id without changing
the other id (birth, volume, domain). However the first time the id
is set, these other ids have to be zeroed.
As similar reparse tags are being used for accessing OneDrive files
and directories, a similar policy has to be used for accessing them.
Until giving full access to OneDrive files with a local copy is
mature enough to have it processed internally, it is safer to have
it delegated to an external plugin. This reverts [4f450a]
When permissions are enabled and setxattr() is rejected, an error
must be returned even though the option silent is set. This is needed
for "cp -p" to know it has to try setting the permissions again and use
chmod().
