[linux-cifs-client] Re: [PATCH] cifs: fix pointer initialization and checks in cifs_follow_symlink (try #3)

[Christoph Hellwig]

On Tue, May 19, 2009 at 10:00:37AM -0400, Jeff Layton wrote:
> diff --git a/fs/cifs/link.c b/fs/cifs/link.c
> index ea9d11e..cd83c53 100644
> --- a/fs/cifs/link.c
> +++ b/fs/cifs/link.c
> @@ -107,48 +107,48 @@ void *
>  cifs_follow_link(struct dentry *direntry, struct nameidata *nd)
>  {
>  	struct inode *inode = direntry->d_inode;
> +	int rc = -ENOMEM;
>  	int xid;
>  	char *full_path = NULL;
> +	char *target_path = NULL;
> +	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
> +	struct cifsTconInfo *tcon = cifs_sb->tcon;
>  
>  	xid = GetXid();
>  
> +	/*
> +	 * For now, we just handle symlinks with unix extensions enabled.
> +	 * Eventually we should handle NTFS reparse points, and MacOS
> +	 * symlink support. For instance...
> +	 *
> +	 * rc = CIFSSMBQueryReparseLinkInfo(...)
> +	 *
> +	 * For now, just return -EACCES when the server doesn't support posix
> +	 * extensions. Note that we still allow querying symlinks when posix
> +	 * extensions are manually disabled. We could disable these as well
> +	 * but there doesn't seem to be any harm in allowing the client to
> +	 * read them.
> +	 */
> +	if (!(tcon->ses->capabilities & CAP_UNIX)) {
> +		rc = -EACCES;
> +		goto out;
> +	}
>  
> +	full_path = build_path_from_dentry(direntry);
>  	if (!full_path)
>  		goto out;
>  
>  	cFYI(1, ("Full path: %s inode = 0x%p", full_path, inode));
>  
> +	rc = CIFSSMBUnixQuerySymLink(xid, tcon, full_path, &target_path,
> +				     cifs_sb->local_nls);
> +	kfree(full_path);
> +out:
>  	if (rc != 0) {
>  		kfree(target_path);
>  		target_path = ERR_PTR(rc);
>  	}

Looks good.