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

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Message-Id: <201101061125.20488.mohan@in.ibm.com>
Date:	Thu, 6 Jan 2011 11:25:20 +0530
From:	"M. Mohan Kumar" <mohan@...ibm.com>
To:	"Aneesh Kumar K. V" <aneesh.kumar@...ux.vnet.ibm.com>
Cc:	"v9fs-developer" <v9fs-developer@...ts.sourceforge.net>,
	linux-fsdevel@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] [V2] fs/9p: TREADLINK bugfix

Thanks Aneesh, I will be posting the patch with addressing your comments.

On Thursday 06 January 2011 10:50:26 am Aneesh Kumar K. V wrote:
> 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

----
M. Mohan Kumar
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