Re: [PATCH v2] erofs: accept source file descriptor via fsconfig

[Gao Xiang <hsiangkao@linux.alibaba.com>]

On 2026/7/11 15:10, Giuseppe Scrivano wrote:
> Add fsparam_fd("source") so that userspace can pass an already-opened
> file descriptor instead of a path string.  When the fd is provided via
> fsconfig(FSCONFIG_SET_FD, "source", NULL, fd), it is stored directly
> in sbi->dif0.file and erofs_fc_get_tree() skips the filp_open() call.
> 
> This is useful for mount namespaces where the backing file may not be
> reachable by path, and for tools that already hold an fd to the image
> (e.g. composefs reusing an erofs mount's backing file).
> 
> Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>

Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>

Thanks,
Gao Xiang