Rust now integrated into bcachefs binary

Rust is now required for building the bcachefs tool, and rust code is
now fully integrated with the C codebase - meaning it is possible to
call back and forth.

The mount helper is now a subcommand, 'mount.bcachefs' is now a small
shell wrapper that invokes 'bcachefs mount'.

This will make it easier to start rewriting other subcommands in rust,
and eventually the whole command line interface.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

1 files changed, 62 insertions, 0 deletions

diff --git a/rust-src/README.md b/rust-src/README.md
new file mode 100644
index 00000000..e4700f6b
--- /dev/null
+++ b/rust-src/README.md
@@ -0,0 +1,62 @@
+Usage
+=====
+
+```
+bcachefs-mount 0.1.0
+Mount a bcachefs filesystem by its UUID
+
+USAGE:
+    bcachefs-mount [OPTIONS] <uuid> <mountpoint>
+
+FLAGS:
+    -h, --help       
+            Prints help information
+
+    -V, --version    
+            Prints version information
+
+
+OPTIONS:
+    -o <options>                 
+            Mount options [default: ]
+
+    -p, --password <password>    
+            Where the password would be loaded from.
+            
+            Possible values are: "fail" - don't ask for password, fail if filesystem is encrypted; "wait" - wait for
+            password to become available before mounting; "ask" -  prompt the user for password; [default: fail]
+
+ARGS:
+    <uuid>          
+            External UUID of the bcachefs filesystem
+
+    <mountpoint>    
+            Where the filesystem should be mounted
+```
+
+Caveats
+=======
+
+* `--password ask` is not yet implemented, but you can use `--password wait`, and load the key with `bcachefs unlock`.
+
+Build
+=====
+
+```sh
+$ git submodule update --init --recursive
+$ cargo build --release
+```
+
+Binary will be built in `target/release/bcachefs-mount`
+
+Dependencies:
+
+* rust
+* blkid
+* uuid
+* liburcu
+* libsodium
+* zlib
+* liblz4
+* libzstd
+* libkeyutils