linux-kernel - Re: [PATCH] [V2] fs/9p: TREADLINK bugfix

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Message-ID: <87zkre38x1.fsf@linux.vnet.ibm.com>
Date:	Thu, 06 Jan 2011 10:50:26 +0530
From:	"Aneesh Kumar K. V" <aneesh.kumar@...ux.vnet.ibm.com>
To:	"M. Mohan Kumar" <mohan@...ibm.com>,
	v9fs-developer <v9fs-developer@...ts.sourceforge.net>,
	"linux-fsdevel\@vger.kernel.org" <linux-fsdevel@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] [V2] fs/9p: TREADLINK bugfix

On Wed,  5 Jan 2011 22:19:56 +0530, "M. Mohan Kumar" <mohan@...ibm.com> wrote:
> Remove v9fs_vfs_readlink_dotl function and use generic_readlink. Update
> v9fs_vfs_follow_link_dotl function to accommodate this change
> 
> Signed-off-by: M. Mohan Kumar <mohan@...ibm.com>
> Reported-by:  Dr. David Alan Gilbert <linux@...blig.org>
> ---
> Changes from previous version:
> * Use __getname in v9fs_vfs_follow_link_dotl
> * Remove v9fs_vfs_readlink_dotl function
> 
>  fs/9p/vfs_inode.c |   53 +++++++++++++++++------------------------------------
>  1 files changed, 17 insertions(+), 36 deletions(-)
> 
> diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
> index 2ce3668..7e613e8 100644
> --- a/fs/9p/vfs_inode.c
> +++ b/fs/9p/vfs_inode.c
> @@ -1994,30 +1994,6 @@ error:
>  	return err;
>  }
> 
> -static int
> -v9fs_vfs_readlink_dotl(struct dentry *dentry, char *buffer, int buflen)
> -{
> -	int retval;
> -	struct p9_fid *fid;
> -	char *target = NULL;
> -
> -	P9_DPRINTK(P9_DEBUG_VFS, " %s\n", dentry->d_name.name);
> -	retval = -EPERM;
> -	fid = v9fs_fid_lookup(dentry);
> -	if (IS_ERR(fid))
> -		return PTR_ERR(fid);
> -
> -	retval = p9_client_readlink(fid, &target);
> -	if (retval < 0)
> -		return retval;
> -
> -	strncpy(buffer, target, buflen);
> -	P9_DPRINTK(P9_DEBUG_VFS, "%s -> %s\n", dentry->d_name.name, buffer);
> -
> -	retval = strnlen(buffer, buflen);
> -	return retval;
> -}
> -
>  /**
>   * v9fs_vfs_follow_link_dotl - follow a symlink path
>   * @dentry: dentry for symlink
> @@ -2028,23 +2004,28 @@ v9fs_vfs_readlink_dotl(struct dentry *dentry, char *buffer, int buflen)
>  static void *
>  v9fs_vfs_follow_link_dotl(struct dentry *dentry, struct nameidata *nd)
>  {
> -	int len = 0;
> +	int retval;
> +	struct p9_fid *fid;
>  	char *link = __getname();
> +	char *target;
> 
> -	P9_DPRINTK(P9_DEBUG_VFS, "%s n", dentry->d_name.name);
> +	P9_DPRINTK(P9_DEBUG_VFS, "%s\n", dentry->d_name.name);
> 
>  	if (!link)
> -		link = ERR_PTR(-ENOMEM);
> -	else {
> -		len = v9fs_vfs_readlink_dotl(dentry, link, PATH_MAX);
> -		if (len < 0) {
> -			__putname(link);
> -			link = ERR_PTR(len);
> -		} else
> -			link[min(len, PATH_MAX-1)] = 0;
> +		return NULL;
> +	fid = v9fs_fid_lookup(dentry);
> +	if (IS_ERR(fid))
> +		return fid;

need to do a __putname(link) and do a nd_set_link(nd, ERR_PTR(fid))

> +	retval = p9_client_readlink(fid, &target);
> +	if (retval < 0) {
> +		__putname(link);
> +		kfree(target);

On error target should not be allocated right ? So why kfree ?

> +		return NULL;
>  	}
> -	nd_set_link(nd, link);
> 
> +	strcpy(link, target);
> +	nd_set_link(nd, link);
> +	kfree(target);
>  	return NULL;
>  }
> 

-aneesh
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