[PATCH v2] AOSP: erofs-utils: fix sub-directory prefix for canned fs_config

[Huang Jianan]

Hi Xiang,

This patch works well with or without --fs-config-file in build.

Tested-by: Huang Jianan <huangjianan at oppo.com>

Thanks,

Jianan

在 2020/12/28 18:51, Gao Xiang 写道:
> From: Gao Xiang <hsiangkao at aol.com>
>
> "failed to find [%s] in canned fs_config" was observed by using
> "--fs-config-file" option as reported by Yue Hu [1].
>
> The root cause was that the mountpoint prefix to subdirectories is
> also needed if "--mount-point" presents. However, such prefix cannot
> be added by just using erofs_fspath().
>
> One exception is that the root directory itself needs to be handled
> specially for canned fs_config. For such case, the prefix of the root
> directory has to be dropped instead.
>
> [1] https://lkml.kernel.org/r/20201222020430.12512-1-zbestahu@gmail.com
>
> Link: https://lore.kernel.org/r/20201226062736.29920-1-hsiangkao@aol.com
> Fixes: 8a9e8046f170 ("AOSP: erofs-utils: add fs_config support")
> Reported-by: Yue Hu <huyue2 at yulong.com>
> Signed-off-by: Gao Xiang <hsiangkao at aol.com>
> ---
> changes since v2:
>   - fix IS_ROOT misuse reported by Jianan, very sorry about this since
>     I know little about canned fs_config.
>
> (please kindly test again...)
>
>   lib/inode.c | 39 +++++++++++++++++++++++++--------------
>   1 file changed, 25 insertions(+), 14 deletions(-)
>
> diff --git a/lib/inode.c b/lib/inode.c
> index 0c4839d..e6159c9 100644
> --- a/lib/inode.c
> +++ b/lib/inode.c
> @@ -696,32 +696,43 @@ int erofs_droid_inode_fsconfig(struct erofs_inode *inode,
>   	/* filesystem_config does not preserve file type bits */
>   	mode_t stat_file_type_mask = st->st_mode & S_IFMT;
>   	unsigned int uid = 0, gid = 0, mode = 0;
> -	char *fspath;
> +	const char *fspath;
> +	char *decorated = NULL;
>   
>   	inode->capabilities = 0;
> +	if (!cfg.fs_config_file && !cfg.mount_point)
> +		return 0;
> +
> +	if (!cfg.mount_point ||
> +	/* have to drop the mountpoint for rootdir of canned fsconfig */
> +	    (cfg.fs_config_file && erofs_fspath(path)[0] == '\0')) {
> +		fspath = erofs_fspath(path);
> +	} else {
> +		if (asprintf(&decorated, "%s/%s", cfg.mount_point,
> +			     erofs_fspath(path)) <= 0)
> +			return -ENOMEM;
> +		fspath = decorated;
> +	}
> +
>   	if (cfg.fs_config_file)
> -		canned_fs_config(erofs_fspath(path),
> +		canned_fs_config(fspath,
>   				 S_ISDIR(st->st_mode),
>   				 cfg.target_out_path,
>   				 &uid, &gid, &mode, &inode->capabilities);
> -	else if (cfg.mount_point) {
> -		if (asprintf(&fspath, "%s/%s", cfg.mount_point,
> -			     erofs_fspath(path)) <= 0)
> -			return -ENOMEM;
> -
> +	else
>   		fs_config(fspath, S_ISDIR(st->st_mode),
>   			  cfg.target_out_path,
>   			  &uid, &gid, &mode, &inode->capabilities);
> -		free(fspath);
> -	}
> -	st->st_uid = uid;
> -	st->st_gid = gid;
> -	st->st_mode = mode | stat_file_type_mask;
>   
>   	erofs_dbg("/%s -> mode = 0x%x, uid = 0x%x, gid = 0x%x, "
>   		  "capabilities = 0x%" PRIx64 "\n",
> -		  erofs_fspath(path),
> -		  mode, uid, gid, inode->capabilities);
> +		  fspath, mode, uid, gid, inode->capabilities);
> +
> +	if (decorated)
> +		free(decorated);
> +	st->st_uid = uid;
> +	st->st_gid = gid;
> +	st->st_mode = mode | stat_file_type_mask;
>   	return 0;
>   }
>   #else