Hi Giuseppe, On Wed, Jul 08, 2026 at 11:34:27AM +0200, Giuseppe Scrivano wrote: > Add EROFS_IOC_GET_SOURCE_FD ioctl that returns a file descriptor to the > backing image file for file-backed erofs mounts. > > Returns -ENOENT for block-device-backed erofs mounts where there is no > backing file. > > The UAPI constant is defined in include/uapi/linux/erofs.h. > > Signed-off-by: Giuseppe Scrivano <[email protected]>
Thanks for the patch! The functionality is indeed useful to users, but similar to overlayfs one, I'm not sure if the interface is the best way. Since after we add this to EROFS, we will support this way forever. I wonder if there could be a way as a common vfs uapi to get source fds, but I don't have better ideas for now... (that is why I suggested to Cc linux-api too..) Thanks, Gao Xiang
