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Commit d1aa0825 authored by Chuck Lever's avatar Chuck Lever Committed by Trond Myklebust
Browse files

NFS: Support raw IPv6 address hostnames during NFS mount operation 



Traditionally the mount command has looked for a ":" to separate the
server's hostname from the export path in the mounted on device name,
like this:

	mount server:/export /mounted/on/dir

The server's hostname is "server" and the export path is "/export".

You can also substitute a specific IPv4 network address for the server
hostname, like this:

	mount 192.168.0.55:/export /mounted/on/dir

Raw IPv6 addresses present a problem, however, because they look
something like this:

	fe80::200:5aff:fe00:30b

Note the use of colons.

To get around the presence of colons, copy the Solaris convention used for
mounting IPv6 servers by address: wrap a raw IPv6 address with square
brackets.

Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent dc045898

fs/nfs/super.c

+82 −8
Original line number Diff line number Diff line
@@ -1195,12 +1195,7 @@ static int nfs_try_mount(struct nfs_parsed_mount_data *args, 
	return status;

}



/*

 * Split "dev_name" into "hostname:export_path".

 *

 * Note: caller frees hostname and export path, even on error.

 */

static int nfs_parse_devname(const char *dev_name,

static int nfs_parse_simple_hostname(const char *dev_name,

				     char **hostname, size_t maxnamlen,

				     char **export_path, size_t maxpathlen)

{
@@ -1256,6 +1251,85 @@ static int nfs_parse_devname(const char *dev_name, 
	return -ENAMETOOLONG;

}



/*

 * Hostname has square brackets around it because it contains one or

 * more colons.  We look for the first closing square bracket, and a

 * colon must follow it.

 */

static int nfs_parse_protected_hostname(const char *dev_name,

					char **hostname, size_t maxnamlen,

					char **export_path, size_t maxpathlen)

{

	size_t len;

	char *start, *end;



	start = (char *)(dev_name + 1);



	end = strchr(start, ']');

	if (end == NULL)

		goto out_bad_devname;

	if (*(end + 1) != ':')

		goto out_bad_devname;



	len = end - start;

	if (len > maxnamlen)

		goto out_hostname;



	/* N.B. caller will free nfs_server.hostname in all cases */

	*hostname = kstrndup(start, len, GFP_KERNEL);

	if (*hostname == NULL)

		goto out_nomem;



	end += 2;

	len = strlen(end);

	if (len > maxpathlen)

		goto out_path;

	*export_path = kstrndup(end, len, GFP_KERNEL);

	if (!*export_path)

		goto out_nomem;



	return 0;



out_bad_devname:

	dfprintk(MOUNT, "NFS: device name not in host:path format\n");

	return -EINVAL;



out_nomem:

	dfprintk(MOUNT, "NFS: not enough memory to parse device name\n");

	return -ENOMEM;



out_hostname:

	dfprintk(MOUNT, "NFS: server hostname too long\n");

	return -ENAMETOOLONG;



out_path:

	dfprintk(MOUNT, "NFS: export pathname too long\n");

	return -ENAMETOOLONG;

}



/*

 * Split "dev_name" into "hostname:export_path".

 *

 * The leftmost colon demarks the split between the server's hostname

 * and the export path.  If the hostname starts with a left square

 * bracket, then it may contain colons.

 *

 * Note: caller frees hostname and export path, even on error.

 */

static int nfs_parse_devname(const char *dev_name,

			     char **hostname, size_t maxnamlen,

			     char **export_path, size_t maxpathlen)

{

	if (*dev_name == '[')

		return nfs_parse_protected_hostname(dev_name,

						    hostname, maxnamlen,

						    export_path, maxpathlen);



	return nfs_parse_simple_hostname(dev_name,

					 hostname, maxnamlen,

					 export_path, maxpathlen);

}



/*

 * Validate the NFS2/NFS3 mount data

 * - fills in the mount root filehandle