Merge tag 'ntfs-for-7.1-rc1-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/linkinjeon/ntfs

Pull ntfs resurrection from Namjae Jeon:
 "Ever since Kari Argillander’s 2022 report [1] regarding the state of
  the ntfs3 driver, I have spent the last 4 years working to provide
  full write support and current trends (iomap, no buffer head, folio),
  enhanced performance, stable maintenance, utility support including
  fsck for NTFS in Linux.

  This new implementation is built upon the clean foundation of the
  original read-only NTFS driver, adding:

   - Write support:

     Implemented full write support based on the classic read-only NTFS
     driver. Added delayed allocation to improve write performance
     through multi-cluster allocation and reduced fragmentation of the
     cluster bitmap.

   - iomap conversion:

     Switched buffered IO (reads/writes), direct IO, file extent
     mapping, readpages, and writepages to use iomap.

   - Remove buffer_head:

     Completely removed buffer_head usage by converting to folios. As a
     result, the dependency on CONFIG_BUFFER_HEAD has been removed from
     Kconfig.

   - Stability improvements:

     The new ntfs driver passes 326 xfstests, compared to 273 for ntfs3.
     All tests passed by ntfs3 are a complete subset of the tests passed
     by this implementation. Added support for fallocate, idmapped
     mounts, permissions, and more.

  xfstests Results report:

     Total tests run: 787
     Passed         : 326
     Failed         : 38
     Skipped        : 423

  Failed tests breakdown:
    - 34 tests require metadata journaling
    - 4 other tests:
         094: No unwritten extent concept in NTFS on-disk format
         563: cgroup v2 aware writeback accounting not supported
         631: RENAME_WHITEOUT support required
         787: NFS delegation test"

Link: https://lore.kernel.org/all/da20d32b-5185-f40b-48b8-2986922d8b25@stargateuniverse.net/ [1]

[ Let's see if this undead filesystem ends up being of the "Easter
  miracle" kind, or the "Nosferatu of filesystems" kind... ]

* tag 'ntfs-for-7.1-rc1-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/linkinjeon/ntfs: (46 commits)
  ntfs: remove redundant out-of-bound checks
  ntfs: add bound checking to ntfs_external_attr_find
  ntfs: add bound checking to ntfs_attr_find
  ntfs: fix ignoring unreachable code warnings
  ntfs: fix inconsistent indenting warnings
  ntfs: fix variable dereferenced before check warnings
  ntfs: prefer IS_ERR_OR_NULL() over manual NULL check
  ntfs: harden ntfs_listxattr against EA entries
  ntfs: harden ntfs_ea_lookup against malformed EA entries
  ntfs: check $EA query-length in ntfs_ea_get
  ntfs: validate WSL EA payload sizes
  ntfs: fix WSL ea restore condition
  ntfs: add missing newlines to pr_err() messages
  ntfs: fix pointer/integer casting warnings
  ntfs: use ->mft_no instead of ->i_ino in prints
  ntfs: change mft_no type to u64
  ntfs: select FS_IOMAP in Kconfig
  ntfs: add MODULE_ALIAS_FS
  ntfs: reduce stack usage in ntfs_write_mft_block()
  ntfs: fix sysctl table registration and path
  ...

2 files changed, 160 insertions, 0 deletions

diff --git a/Documentation/filesystems/index.rst b/Documentation/filesystems/index.rst
index 6cbc3e0292ae..fc7254d01a2b 100644
--- a/Documentation/filesystems/index.rst
+++ b/Documentation/filesystems/index.rst
@@ -99,6 +99,7 @@ Documentation for filesystem implementations.
    isofs
    nilfs2
    nfs/index
+   ntfs
    ntfs3
    ocfs2
    ocfs2-online-filecheck
diff --git a/Documentation/filesystems/ntfs.rst b/Documentation/filesystems/ntfs.rst
new file mode 100644
index 000000000000..5c96b04a4d7a
--- /dev/null
+++ b/Documentation/filesystems/ntfs.rst
@@ -0,0 +1,159 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=================================
+The Linux NTFS filesystem driver
+=================================
+
+
+.. Table of contents
+
+   - Overview
+   - Utilities support
+   - Supported mount options
+
+
+Overview
+========
+
+NTFS is a Linux kernel filesystem driver that provides full read and write
+support for NTFS volumes. It is designed for high performance, modern
+kernel infrastructure (iomap, folio), and stable long-term maintenance.
+
+
+Utilities support
+=================
+
+The NTFS utilities project, called ntfsprogs-plus, provides mkfs.ntfs,
+fsck.ntfs, and other related tools (e.g., ntfsinfo, ntfsclone, etc.) for
+creating, checking, and managing NTFS volumes. These utilities can be used
+for filesystem testing with xfstests as well as for recovering corrupted
+NTFS devices.
+
+The project is available at:
+
+  https://github.com/ntfsprogs-plus/ntfsprogs-plus
+
+
+Supported mount options
+=======================
+
+The NTFS driver supports the following mount options:
+
+======================= ====================================================
+iocharset=name          Character set to use for converting between
+                        the encoding is used for user visible filename and
+                        16 bit Unicode characters.
+
+nls=name                Deprecated option.  Still supported but please use
+                        iocharset=name in the future.
+
+uid=
+gid=
+umask=                  Provide default owner, group, and access mode mask.
+                        These options work as documented in mount(8).  By
+                        default, the files/directories are owned by root
+                        and he/she has read and write permissions, as well
+                        as browse permission for directories.  No one else
+                        has any access permissions.  I.e. the mode on all
+                        files is by default rw------- and
+                        for directories rwx------, a consequence of
+                        the default fmask=0177 and dmask=0077.
+                        Using a umask of zero will grant all permissions to
+                        everyone, i.e. all files and directories will have
+                        mode rwxrwxrwx.
+
+fmask=
+dmask=                  Instead of specifying umask which applies both to
+                        files and directories, fmask applies only to files
+                        and dmask only to directories.
+
+showmeta=<BOOL>
+show_sys_files=<BOOL>   If show_sys_files is specified, show the system
+                        files in directory listings.  Otherwise the default
+                        behaviour is to hide the system files.
+                        Note that even when show_sys_files is specified,
+                        "$MFT" will not be visible due to bugs/mis-features
+                        in glibc. Further, note that irrespective of
+                        show_sys_files, all files are accessible by name,
+                        i.e. you can always do "ls -l \$UpCase" for example
+                        to specifically show the system file containing
+                        the Unicode upcase table.
+
+case_sensitive=<BOOL>   If case_sensitive is specified, treat all filenames
+                        as case sensitive and create file names in
+                        the POSIX namespace (default behavior). Note,
+                        the Linux NTFS driver will never create short
+                        filenames and will remove them on rename/delete of
+                        the corresponding long file name. Note that files
+                        remain accessible via their short file name, if it
+                        exists.
+
+nocase=<BOOL>           If nocase is specified, treat filenames
+                        case-insensitively.
+
+disable_sparse=<BOOL>   If disable_sparse is specified, creation of sparse
+                        regions, i.e. holes, inside files is disabled for
+                        the volume (for the duration of this mount only).
+                        By default, creation of sparse regions is enabled,
+                        which is consistent with the behaviour of
+                        traditional Unix filesystems.
+
+errors=opt              Specify NTFS behavior on critical errors: panic,
+                        remount the partition in read-only mode or
+                        continue without doing anything (default behavior).
+
+mft_zone_multiplier=    Set the MFT zone multiplier for the volume (this
+                        setting is not persistent across mounts and can be
+                        changed from mount to mount but cannot be changed
+                        on remount).  Values of 1 to 4 are allowed, 1 being
+                        the default.  The MFT zone multiplier determines
+                        how much space is reserved for the MFT on the
+                        volume.  If all other space is used up, then the
+                        MFT zone will be shrunk dynamically, so this has no
+                        impact on the amount of free space.  However, it
+                        can have an impact on performance by affecting
+                        fragmentation of the MFT. In general use the
+                        default.  If you have a lot of small files then use
+                        a higher value.  The values have the following
+                        meaning:
+
+                        =====   =================================
+                        Value   MFT zone size (% of volume size)
+                        =====   =================================
+                          1             12.5%
+                          2             25%
+                          3             37.5%
+                          4             50%
+                        =====   =================================
+
+                        Note this option is irrelevant for read-only mount.
+
+preallocated_size=      Set preallocated size to optimize runlist merge
+                        overhead with small chunck size.(64KB size by
+                        default)
+
+acl=<BOOL>              Enable POSIX ACL support. When specified, POSIX
+                        ACLs stored in extended attributes are enforced.
+                        Default is off. Requires kernel config
+                        NTFS_FS_POSIX_ACL enabled.
+
+sys_immutable=<BOOL>    Make NTFS system files (e.g. $MFT, $LogFile,
+                        $Bitmap, $UpCase, etc.) immutable to user initiated
+                        modifications for extra safety. Default is off.
+
+nohidden=<BOOL>         Hide files and directories marked with the Windows
+                        "hidden" attribute. By default hidden items are
+                        shown.
+
+hide_dot_files=<BOOL>   Hide names beginning with a dot ("."). By default
+                        dot files are shown. When enabled, files and
+                        directories created with a leading '.' will be
+                        hidden from directory listings.
+
+windows_names=<BOOL>    Refuse creation/rename of files with characters or
+                        reserved device names disallowed on Windows (e.g.
+                        CON, NUL, AUX, COM1, LPT1, etc.). Default is off.
+discard=<BOOL>          Issue block device discard for clusters freed on
+                        file deletion/truncation to inform underlying
+                        storage.
+======================= ====================================================