[PATCH] nfs: Enclose hostname in brackets when needed in nfs_do_root_mount

[PATCH] nfs: Enclose hostname in brackets when needed in nfs_do_root_mount

[Jan Kara]

When hostname contains colon (e.g. when it is an IPv6 address) it needs
to be enclosed in brackets to make parsing of NFS device string possible.
Fix nfs_do_root_mount() to enclose hostname properly when needed. NFS code
actually does not need this as it does not parse the string passed by
nfs_do_root_mount() but the device string is exposed to userspace in
/proc/mounts.

CC: Josh Boyer <jwboyer@redhat.com>
CC: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/nfs/super.c |    8 ++++++--
 1 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index b961cea..42b74f8 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -2694,11 +2694,15 @@ static struct vfsmount *nfs_do_root_mount(struct file_system_type *fs_type,
 	char *root_devname;
 	size_t len;
 
-	len = strlen(hostname) + 3;
+	len = strlen(hostname) + 5;
 	root_devname = kmalloc(len, GFP_KERNEL);
 	if (root_devname == NULL)
 		return ERR_PTR(-ENOMEM);
-	snprintf(root_devname, len, "%s:/", hostname);
+	/* Does hostname needs to be enclosed in brackets? */
+	if (strchr(hostname, ':'))
+		snprintf(root_devname, len, "[%s]:/", hostname);
+	else
+		snprintf(root_devname, len, "%s:/", hostname);
 	root_mnt = vfs_kern_mount(fs_type, flags, root_devname, data);
 	kfree(root_devname);
 	return root_mnt;
-- 
1.7.1

RE: [PATCH] nfs: Enclose hostname in brackets when needed in nfs_do_root_mount

[Myklebust, Trond]

> -----Original Message-----
> From: Jan Kara [mailto:jack@suse.cz]
> Sent: Friday, September 02, 2011 7:10 PM
> To: Myklebust, Trond
> Cc: linux-nfs@vger.kernel.org; Jan Kara; Josh Boyer; Myklebust, Trond
> Subject: [PATCH] nfs: Enclose hostname in brackets when needed in
> nfs_do_root_mount
> 
> When hostname contains colon (e.g. when it is an IPv6 address) it
needs
> to be enclosed in brackets to make parsing of NFS device string
> possible.
> Fix nfs_do_root_mount() to enclose hostname properly when needed. NFS
> code
> actually does not need this as it does not parse the string passed by
> nfs_do_root_mount() but the device string is exposed to userspace in
> /proc/mounts.
> 
> CC: Josh Boyer <jwboyer@redhat.com>
> CC: Trond Myklebust <Trond.Myklebust@netapp.com>
> Signed-off-by: Jan Kara <jack@suse.cz>
> ---
>  fs/nfs/super.c |    8 ++++++--
>  1 files changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/nfs/super.c b/fs/nfs/super.c
> index b961cea..42b74f8 100644
> --- a/fs/nfs/super.c
> +++ b/fs/nfs/super.c
> @@ -2694,11 +2694,15 @@ static struct vfsmount
> *nfs_do_root_mount(struct file_system_type *fs_type,
>  	char *root_devname;
>  	size_t len;
> 
> -	len = strlen(hostname) + 3;
> +	len = strlen(hostname) + 5;
>  	root_devname = kmalloc(len, GFP_KERNEL);
>  	if (root_devname == NULL)
>  		return ERR_PTR(-ENOMEM);
> -	snprintf(root_devname, len, "%s:/", hostname);
> +	/* Does hostname needs to be enclosed in brackets? */
> +	if (strchr(hostname, ':'))
> +		snprintf(root_devname, len, "[%s]:/", hostname);
> +	else
> +		snprintf(root_devname, len, "%s:/", hostname);

What if the hostname is already enclosed in brackets, as is usually the
case if I enter an IPv6 address instead of a DNS name? Won't this cause
it to be bracketed twice?

IOW: If I try to

	mount -t nfs [fe80::20c:29ff:fee9:83e6]:/export /mnt

won't the above end up returning a hostname of [[::20c:29ff:fee9:83e6]]?

Cheers
   Trond

Re: [PATCH] nfs: Enclose hostname in brackets when needed in nfs_do_root_mount

[Jan Kara]

On Fri 02-09-11 16:23:43, Myklebust, Trond wrote:
> > -----Original Message-----
> > From: Jan Kara [mailto:jack@suse.cz]
> > Sent: Friday, September 02, 2011 7:10 PM
> > To: Myklebust, Trond
> > Cc: linux-nfs@vger.kernel.org; Jan Kara; Josh Boyer; Myklebust, Trond
> > Subject: [PATCH] nfs: Enclose hostname in brackets when needed in
> > nfs_do_root_mount
> > 
> > When hostname contains colon (e.g. when it is an IPv6 address) it
> needs
> > to be enclosed in brackets to make parsing of NFS device string
> > possible.
> > Fix nfs_do_root_mount() to enclose hostname properly when needed. NFS
> > code
> > actually does not need this as it does not parse the string passed by
> > nfs_do_root_mount() but the device string is exposed to userspace in
> > /proc/mounts.
> > 
> > CC: Josh Boyer <jwboyer@redhat.com>
> > CC: Trond Myklebust <Trond.Myklebust@netapp.com>
> > Signed-off-by: Jan Kara <jack@suse.cz>
> > ---
> >  fs/nfs/super.c |    8 ++++++--
> >  1 files changed, 6 insertions(+), 2 deletions(-)
> > 
> > diff --git a/fs/nfs/super.c b/fs/nfs/super.c
> > index b961cea..42b74f8 100644
> > --- a/fs/nfs/super.c
> > +++ b/fs/nfs/super.c
> > @@ -2694,11 +2694,15 @@ static struct vfsmount
> > *nfs_do_root_mount(struct file_system_type *fs_type,
> >  	char *root_devname;
> >  	size_t len;
> > 
> > -	len = strlen(hostname) + 3;
> > +	len = strlen(hostname) + 5;
> >  	root_devname = kmalloc(len, GFP_KERNEL);
> >  	if (root_devname == NULL)
> >  		return ERR_PTR(-ENOMEM);
> > -	snprintf(root_devname, len, "%s:/", hostname);
> > +	/* Does hostname needs to be enclosed in brackets? */
> > +	if (strchr(hostname, ':'))
> > +		snprintf(root_devname, len, "[%s]:/", hostname);
> > +	else
> > +		snprintf(root_devname, len, "%s:/", hostname);
> 
> What if the hostname is already enclosed in brackets, as is usually the
> case if I enter an IPv6 address instead of a DNS name? Won't this cause
> it to be bracketed twice?
> 
> IOW: If I try to
> 
> 	mount -t nfs [fe80::20c:29ff:fee9:83e6]:/export /mnt
> 
> won't the above end up returning a hostname of [[::20c:29ff:fee9:83e6]]?
  No it won't - I've actually verified my patch with experiment ;). The
hostname nfs_do_root_mount() gets is already without possible brackets
(these have been removed when we first parsed the string passed from
userspace by nfs_parse_devname() - yes, it took me some time to drill
through the NFS call stack during mount to actually find out who removes
the brackets from the passed hostname and who composes the device name back
without them).

								Honza
-- 
Jan Kara <jack@suse.cz>
SUSE Labs, CR

Re: [PATCH] nfs: Enclose hostname in brackets when needed in nfs_do_root_mount

[Jan Kara]

On Sat 03-09-11 02:22:31, Jan Kara wrote:
> On Fri 02-09-11 16:23:43, Myklebust, Trond wrote:
> > > -----Original Message-----
> > > From: Jan Kara [mailto:jack@suse.cz]
> > > Sent: Friday, September 02, 2011 7:10 PM
> > > To: Myklebust, Trond
> > > Cc: linux-nfs@vger.kernel.org; Jan Kara; Josh Boyer; Myklebust, Trond
> > > Subject: [PATCH] nfs: Enclose hostname in brackets when needed in
> > > nfs_do_root_mount
> > > 
> > > When hostname contains colon (e.g. when it is an IPv6 address) it
> > needs
> > > to be enclosed in brackets to make parsing of NFS device string
> > > possible.
> > > Fix nfs_do_root_mount() to enclose hostname properly when needed. NFS
> > > code
> > > actually does not need this as it does not parse the string passed by
> > > nfs_do_root_mount() but the device string is exposed to userspace in
> > > /proc/mounts.
> > > 
> > > CC: Josh Boyer <jwboyer@redhat.com>
> > > CC: Trond Myklebust <Trond.Myklebust@netapp.com>
> > > Signed-off-by: Jan Kara <jack@suse.cz>
> > > ---
> > >  fs/nfs/super.c |    8 ++++++--
> > >  1 files changed, 6 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/fs/nfs/super.c b/fs/nfs/super.c
> > > index b961cea..42b74f8 100644
> > > --- a/fs/nfs/super.c
> > > +++ b/fs/nfs/super.c
> > > @@ -2694,11 +2694,15 @@ static struct vfsmount
> > > *nfs_do_root_mount(struct file_system_type *fs_type,
> > >  	char *root_devname;
> > >  	size_t len;
> > > 
> > > -	len = strlen(hostname) + 3;
> > > +	len = strlen(hostname) + 5;
> > >  	root_devname = kmalloc(len, GFP_KERNEL);
> > >  	if (root_devname == NULL)
> > >  		return ERR_PTR(-ENOMEM);
> > > -	snprintf(root_devname, len, "%s:/", hostname);
> > > +	/* Does hostname needs to be enclosed in brackets? */
> > > +	if (strchr(hostname, ':'))
> > > +		snprintf(root_devname, len, "[%s]:/", hostname);
> > > +	else
> > > +		snprintf(root_devname, len, "%s:/", hostname);
> > 
> > What if the hostname is already enclosed in brackets, as is usually the
> > case if I enter an IPv6 address instead of a DNS name? Won't this cause
> > it to be bracketed twice?
> > 
> > IOW: If I try to
> > 
> > 	mount -t nfs [fe80::20c:29ff:fee9:83e6]:/export /mnt
> > 
> > won't the above end up returning a hostname of [[::20c:29ff:fee9:83e6]]?
>   No it won't - I've actually verified my patch with experiment ;). The
> hostname nfs_do_root_mount() gets is already without possible brackets
> (these have been removed when we first parsed the string passed from
> userspace by nfs_parse_devname() - yes, it took me some time to drill
> through the NFS call stack during mount to actually find out who removes
> the brackets from the passed hostname and who composes the device name back
> without them).
  Ping? Trond, will you merge the patch please? I guess it got somehow
lost.

								Honza

Re: [PATCH] nfs: Enclose hostname in brackets when needed in nfs_do_root_mount

[Josh Boyer]

On Tue, Nov 08, 2011 at 02:06:08PM +0100, Jan Kara wrote:
> On Sat 03-09-11 02:22:31, Jan Kara wrote:
> > On Fri 02-09-11 16:23:43, Myklebust, Trond wrote:
> > > > -----Original Message-----
> > > > From: Jan Kara [mailto:jack@suse.cz]
> > > > Sent: Friday, September 02, 2011 7:10 PM
> > > > To: Myklebust, Trond
> > > > Cc: linux-nfs@vger.kernel.org; Jan Kara; Josh Boyer; Myklebust, Trond
> > > > Subject: [PATCH] nfs: Enclose hostname in brackets when needed in
> > > > nfs_do_root_mount
> > > > 
> > > > When hostname contains colon (e.g. when it is an IPv6 address) it
> > > needs
> > > > to be enclosed in brackets to make parsing of NFS device string
> > > > possible.
> > > > Fix nfs_do_root_mount() to enclose hostname properly when needed. NFS
> > > > code
> > > > actually does not need this as it does not parse the string passed by
> > > > nfs_do_root_mount() but the device string is exposed to userspace in
> > > > /proc/mounts.
> > > > 
> > > > CC: Josh Boyer <jwboyer@redhat.com>
> > > > CC: Trond Myklebust <Trond.Myklebust@netapp.com>
> > > > Signed-off-by: Jan Kara <jack@suse.cz>
> > > > ---
> > > >  fs/nfs/super.c |    8 ++++++--
> > > >  1 files changed, 6 insertions(+), 2 deletions(-)
> > > > 
> > > > diff --git a/fs/nfs/super.c b/fs/nfs/super.c
> > > > index b961cea..42b74f8 100644
> > > > --- a/fs/nfs/super.c
> > > > +++ b/fs/nfs/super.c
> > > > @@ -2694,11 +2694,15 @@ static struct vfsmount
> > > > *nfs_do_root_mount(struct file_system_type *fs_type,
> > > >  	char *root_devname;
> > > >  	size_t len;
> > > > 
> > > > -	len = strlen(hostname) + 3;
> > > > +	len = strlen(hostname) + 5;
> > > >  	root_devname = kmalloc(len, GFP_KERNEL);
> > > >  	if (root_devname == NULL)
> > > >  		return ERR_PTR(-ENOMEM);
> > > > -	snprintf(root_devname, len, "%s:/", hostname);
> > > > +	/* Does hostname needs to be enclosed in brackets? */
> > > > +	if (strchr(hostname, ':'))
> > > > +		snprintf(root_devname, len, "[%s]:/", hostname);
> > > > +	else
> > > > +		snprintf(root_devname, len, "%s:/", hostname);
> > > 
> > > What if the hostname is already enclosed in brackets, as is usually the
> > > case if I enter an IPv6 address instead of a DNS name? Won't this cause
> > > it to be bracketed twice?
> > > 
> > > IOW: If I try to
> > > 
> > > 	mount -t nfs [fe80::20c:29ff:fee9:83e6]:/export /mnt
> > > 
> > > won't the above end up returning a hostname of [[::20c:29ff:fee9:83e6]]?
> >   No it won't - I've actually verified my patch with experiment ;). The
> > hostname nfs_do_root_mount() gets is already without possible brackets
> > (these have been removed when we first parsed the string passed from
> > userspace by nfs_parse_devname() - yes, it took me some time to drill
> > through the NFS call stack during mount to actually find out who removes
> > the brackets from the passed hostname and who composes the device name back
> > without them).
>   Ping? Trond, will you merge the patch please? I guess it got somehow
> lost.

Did this patch ever get queued up?  I don't see it in Linus' tree or
linux-next so I'm guessing no.  Is there a reason why?

josh