Re: [PATCH] debufgs: debugfs_create_blob can set the file size

["Darrick J. Wong" <djwong@kernel.org>]

On Wed, Feb 07, 2024 at 02:06:19PM -0600, Timur Tabi wrote:
> debugfs_create_blob() is given the size of the blob, so use it to
> also set the size of the dentry.  For example, efi=debug previously
> showed
> 
> -r-------- 1 root root 0 Feb  7 13:30 boot_services_code0
> -r-------- 1 root root 0 Feb  7 13:30 boot_services_code1
> -r-------- 1 root root 0 Feb  7 13:30 boot_services_data0
> -r-------- 1 root root 0 Feb  7 13:30 boot_services_data1
> -r-------- 1 root root 0 Feb  7 13:30 boot_services_data2
> -r-------- 1 root root 0 Feb  7 13:30 boot_services_data3
> -r-------- 1 root root 0 Feb  7 13:30 boot_services_data4
> 
> but with this patch it shows
> 
> -r-------- 1 root root  12783616 Feb  7 13:26 boot_services_code0
> -r-------- 1 root root    262144 Feb  7 13:26 boot_services_code1
> -r-------- 1 root root  41705472 Feb  7 13:26 boot_services_data0
> -r-------- 1 root root  23187456 Feb  7 13:26 boot_services_data1
> -r-------- 1 root root 110645248 Feb  7 13:26 boot_services_data2
> -r-------- 1 root root   1048576 Feb  7 13:26 boot_services_data3
> -r-------- 1 root root      4096 Feb  7 13:26 boot_services_data4
> 
> Signed-off-by: Timur Tabi <ttabi@nvidia.com>
> ---
>  fs/debugfs/file.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c
> index c6f4a9a98b85..d97800603a8f 100644
> --- a/fs/debugfs/file.c
> +++ b/fs/debugfs/file.c
> @@ -1152,7 +1152,14 @@ struct dentry *debugfs_create_blob(const char *name, umode_t mode,
>  				   struct dentry *parent,
>  				   struct debugfs_blob_wrapper *blob)
>  {
> -	return debugfs_create_file_unsafe(name, mode & 0644, parent, blob, &fops_blob);
> +	struct dentry *dentry;
> +
> +	dentry = debugfs_create_file_unsafe(name, mode & 0644, parent, blob, &fops_blob);
> +	if (!IS_ERR(dentry))
> +		d_inode(dentry)->i_size = blob->size;

Aren't you supposed to use i_size_write for this?

--D

> +
> +	return dentry;
> +
>  }
>  EXPORT_SYMBOL_GPL(debugfs_create_blob);
>  
> -- 
> 2.34.1
> 
>