7 files changed, 50 insertions, 6 deletions

diff --git a/Documentation/filesystems/autofs.rst b/Documentation/filesystems/autofs.rst
index 1ac576458c69..5eb02394fcc3 100644
--- a/Documentation/filesystems/autofs.rst
+++ b/Documentation/filesystems/autofs.rst
@@ -442,7 +442,7 @@ which can be used to communicate directly with the autofs filesystem.
 It requires CAP_SYS_ADMIN for access.
 
 The 'ioctl's that can be used on this device are described in a separate
-document `autofs-mount-control.txt`, and are summarised briefly here.
+document `autofs-mount-control.rst`, and are summarised briefly here.
 Each ioctl is passed a pointer to an `autofs_dev_ioctl` structure::
 
         struct autofs_dev_ioctl {
diff --git a/Documentation/filesystems/dlmfs.rst b/Documentation/filesystems/dlmfs.rst
index 7e2b1fd471d7..70d4e48242c3 100644
--- a/Documentation/filesystems/dlmfs.rst
+++ b/Documentation/filesystems/dlmfs.rst
@@ -36,7 +36,7 @@ None
 Usage
 =====
 
-If you're just interested in OCFS2, then please see ocfs2.txt. The
+If you're just interested in OCFS2, then please see ocfs2.rst. The
 rest of this document will be geared towards those who want to use
 dlmfs for easy to setup and easy to use clustered locking in
 userspace.
diff --git a/Documentation/filesystems/f2fs.rst b/Documentation/filesystems/f2fs.rst
index 68a0885fb5e6..fb7d2ee022bc 100644
--- a/Documentation/filesystems/f2fs.rst
+++ b/Documentation/filesystems/f2fs.rst
@@ -943,3 +943,47 @@ NVMe Zoned Namespace devices
   can start before the zone-capacity and span across zone-capacity boundary.
   Such spanning segments are also considered as usable segments. All blocks
   past the zone-capacity are considered unusable in these segments.
+
+Device aliasing feature
+-----------------------
+
+f2fs can utilize a special file called a "device aliasing file." This file allows
+the entire storage device to be mapped with a single, large extent, not using
+the usual f2fs node structures. This mapped area is pinned and primarily intended
+for holding the space.
+
+Essentially, this mechanism allows a portion of the f2fs area to be temporarily
+reserved and used by another filesystem or for different purposes. Once that
+external usage is complete, the device aliasing file can be deleted, releasing
+the reserved space back to F2FS for its own use.
+
+<use-case>
+
+# ls /dev/vd*
+/dev/vdb (32GB) /dev/vdc (32GB)
+# mkfs.ext4 /dev/vdc
+# mkfs.f2fs -c /dev/vdc@vdc.file /dev/vdb
+# mount /dev/vdb /mnt/f2fs
+# ls -l /mnt/f2fs
+vdc.file
+# df -h
+/dev/vdb                            64G   33G   32G  52% /mnt/f2fs
+
+# mount -o loop /dev/vdc /mnt/ext4
+# df -h
+/dev/vdb                            64G   33G   32G  52% /mnt/f2fs
+/dev/loop7                          32G   24K   30G   1% /mnt/ext4
+# umount /mnt/ext4
+
+# f2fs_io getflags /mnt/f2fs/vdc.file
+get a flag on /mnt/f2fs/vdc.file ret=0, flags=nocow(pinned),immutable
+# f2fs_io setflags noimmutable /mnt/f2fs/vdc.file
+get a flag on noimmutable ret=0, flags=800010
+set a flag on /mnt/f2fs/vdc.file ret=0, flags=noimmutable
+# rm /mnt/f2fs/vdc.file
+# df -h
+/dev/vdb                            64G  753M   64G   2% /mnt/f2fs
+
+So, the key idea is, user can do any file operations on /dev/vdc, and
+reclaim the space after the use, while the space is counted as /data.
+That doesn't require modifying partition size and filesystem format.
diff --git a/Documentation/filesystems/fsverity.rst b/Documentation/filesystems/fsverity.rst
index 0e2fac7a16da..76e538217868 100644
--- a/Documentation/filesystems/fsverity.rst
+++ b/Documentation/filesystems/fsverity.rst
@@ -16,7 +16,7 @@ btrfs filesystems.  Like fscrypt, not too much filesystem-specific
 code is needed to support fs-verity.
 
 fs-verity is similar to `dm-verity
-<https://www.kernel.org/doc/Documentation/device-mapper/verity.txt>`_
+<https://www.kernel.org/doc/Documentation/admin-guide/device-mapper/verity.rst>`_
 but works on files rather than block devices.  On regular files on
 filesystems supporting fs-verity, userspace can execute an ioctl that
 causes the filesystem to build a Merkle tree for the file and persist
diff --git a/Documentation/filesystems/path-lookup.rst b/Documentation/filesystems/path-lookup.rst
index 2b2df6aa5432..9ced1135608e 100644
--- a/Documentation/filesystems/path-lookup.rst
+++ b/Documentation/filesystems/path-lookup.rst
@@ -531,7 +531,7 @@ this retry process in the next article.
 Automount points are locations in the filesystem where an attempt to
 lookup a name can trigger changes to how that lookup should be
 handled, in particular by mounting a filesystem there.  These are
-covered in greater detail in autofs.txt in the Linux documentation
+covered in greater detail in autofs.rst in the Linux documentation
 tree, but a few notes specifically related to path lookup are in order
 here.
 
diff --git a/Documentation/filesystems/path-lookup.txt b/Documentation/filesystems/path-lookup.txt
index 1aa7ce099f6f..d2cf2852e1f8 100644
--- a/Documentation/filesystems/path-lookup.txt
+++ b/Documentation/filesystems/path-lookup.txt
@@ -379,4 +379,4 @@ Papers and other documentation on dcache locking
 
 2. http://lse.sourceforge.net/locking/dcache/dcache.html
 
-3. path-lookup.md in this directory.
+3. path-lookup.rst in this directory.
diff --git a/Documentation/filesystems/ramfs-rootfs-initramfs.rst b/Documentation/filesystems/ramfs-rootfs-initramfs.rst
index 447f767c6462..fa4f81099cb4 100644
--- a/Documentation/filesystems/ramfs-rootfs-initramfs.rst
+++ b/Documentation/filesystems/ramfs-rootfs-initramfs.rst
@@ -315,7 +315,7 @@ the above threads) is:
 2) The cpio archive format chosen by the kernel is simpler and cleaner (and
    thus easier to create and parse) than any of the (literally dozens of)
    various tar archive formats.  The complete initramfs archive format is
-   explained in buffer-format.txt, created in usr/gen_init_cpio.c, and
+   explained in buffer-format.rst, created in usr/gen_init_cpio.c, and
    extracted in init/initramfs.c.  All three together come to less than 26k
    total of human-readable text.