erofs-utils: introduce fuse implementation

Let's add a simple erofsfuse approach, and benefits are:

 - images can be supported on various platforms;
 - new unpack tool can be developed based on this;
 - new on-disk features can be iterated, verified effectively.

This commit only addresses reading uncompressed regular files.
Other file (e.g. compressed file) support is out of scope here.

Note that erofsfuse is an unstable feature for now (also notice
LZ4_decompress_safe_partial() was broken in lz4-1.9.2, which
just fixed in lz4-1.9.3), let's disable it by default for a while.

Signed-off-by: Li Guifu <>
Signed-off-by: Huang Jianan <>
Signed-off-by: Guo Weichao <>
Signed-off-by: Gao Xiang <>
14 files changed