Re: [PATCH -V14 04/11] vfs: Allow handle based open on symlinks

[Nick Piggin <npiggin@suse.de>]

On Tue, Jun 15, 2010 at 10:42:54PM +0530, Aneesh Kumar K.V wrote:
> The patch update may_open to allow handle based open on symlinks.
> The file handle based API use file descritor returned from open_by_handle_at
> to do different file system operations. To find the link target name we
> need to get a file descriptor on symlinks.
> 
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> ---
>  fs/namei.c |   17 ++++++++++++++---
>  1 files changed, 14 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/namei.c b/fs/namei.c
> index c2d19c7..417bf53 100644
> --- a/fs/namei.c
> +++ b/fs/namei.c
> @@ -1422,7 +1422,7 @@ int vfs_create(struct inode *dir, struct dentry *dentry, int mode,
>  	return error;
>  }
>  
> -int may_open(struct path *path, int acc_mode, int flag)
> +static int __may_open(struct path *path, int acc_mode, int flag, int handle)
>  {
>  	struct dentry *dentry = path->dentry;
>  	struct inode *inode = dentry->d_inode;
> @@ -1433,7 +1433,13 @@ int may_open(struct path *path, int acc_mode, int flag)
>  
>  	switch (inode->i_mode & S_IFMT) {
>  	case S_IFLNK:
> -		return -ELOOP;
> +		/*
> +		 * For file handle based open we should allow
> +		 * open of symlink.
> +		 */
> +		if (!handle)
> +			return -ELOOP;
> +		break;
>  	case S_IFDIR:
>  		if (acc_mode & MAY_WRITE)
>  			return -EISDIR;
> @@ -1473,6 +1479,11 @@ int may_open(struct path *path, int acc_mode, int flag)
>  	return break_lease(inode, flag);
>  }
>  
> +int may_open(struct path *path, int acc_mode, int flag)
> +{
> +	return __may_open(path, acc_mode, flag, 0);
> +}

Why don't you just add MAY_OPEN_LNK instead of this ugliness?