Re: [PATCH v2] erofs-utils: lib: correctly set {u,g}id in erofs_rebuild_make_root()

[Gao Xiang]

On 2026/1/14 15:38, Yifan Zhao wrote:

In rebuild mode, the {u,g}id of the root inode is currently defaulted
to 0 and is not controlled by --force_{u,g}id. This behavior also
causes the {u,g}id of intermediate directories created by
`erofs_rebuild_mkdir()` to be set to 0.

This patch fixes the behavior by explicitly setting permissions for the
root inode:

- If --force-{u,g}id is not specified, it now defaults to the current
    user's {u,g}id.
- If --force-{u,g}id is specified, it correctly updates the ownership
    for all files and directories.

Signed-off-by: Yifan Zhao <zhaoyifa...@huawei.com>
---
  include/erofs/inode.h | 3 ++-
  lib/inode.c           | 5 ++++-
  mkfs/main.c           | 2 +-
  3 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/include/erofs/inode.h b/include/erofs/inode.h
index 8b91771..2a7af31 100644
--- a/include/erofs/inode.h
+++ b/include/erofs/inode.h
@@ -48,7 +48,8 @@ int erofs_importer_load_tree(struct erofs_importer *im, bool 
rebuild,
  struct erofs_inode *erofs_mkfs_build_special_from_fd(struct erofs_importer 
*im,
                                                     int fd, const char *name);
  int erofs_fixup_root_inode(struct erofs_inode *root);
-struct erofs_inode *erofs_rebuild_make_root(struct erofs_sb_info *sbi);
+struct erofs_inode *erofs_rebuild_make_root(struct erofs_importer *im,
+                                           struct erofs_sb_info *sbi);

#ifdef __cplusplus

  }
diff --git a/lib/inode.c b/lib/inode.c
index 26fefa2..4f87757 100644
--- a/lib/inode.c
+++ b/lib/inode.c
@@ -2375,7 +2375,8 @@ int erofs_fixup_root_inode(struct erofs_inode *root)
        return err;
  }

-struct erofs_inode *erofs_rebuild_make_root(struct erofs_sb_info *sbi)

+struct erofs_inode *erofs_rebuild_make_root(struct erofs_importer *im,
+                                           struct erofs_sb_info *sbi)
  {

we could support !im, I mean

        struct erofs_importer_params *params = im ? im->params : NULL;

        struct erofs_inode *root;

@@ -2384,6 +2385,8 @@ struct erofs_inode *erofs_rebuild_make_root(struct erofs_sb_info *sbi)

                return root;
        root->i_srcpath = strdup("/");
        root->i_mode = S_IFDIR | 0777;
+       root->i_uid = im->params->fixed_uid == -1 ? getuid() : 
im->params->fixed_uid;
+       root->i_gid = im->params->fixed_gid == -1 ? getgid() : 
im->params->fixed_gid;

        root->i_uid = params && params->fixed_uid < 0 ? getuid() :
                        params->fixed_uid;
...

Thanks,
Gao Xiang