NFS: Use common device name parsing logic for NFSv4 and NFSv2/v3

To support passing a raw IPv6 address as a server hostname, we need to
expand the logic that handles splitting the passed-in device name into
a server hostname and export path

Start by pulling device name parsing out of the mount option validation
functions and into separate helper functions.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 79 insertions, 45 deletions

diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index b880db18035b..c4ee8b3a27c1 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -1196,6 +1196,67 @@ static int nfs_try_mount(struct nfs_parsed_mount_data *args,
 }
 
 /*
+ * 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,
+                             char **hostname, size_t maxnamlen,
+                             char **export_path, size_t maxpathlen)
+{
+        size_t len;
+        char *colon, *comma;
+
+        colon = strchr(dev_name, ':');
+        if (colon == NULL)
+                goto out_bad_devname;
+
+        len = colon - dev_name;
+        if (len > maxnamlen)
+                goto out_hostname;
+
+        /* N.B. caller will free nfs_server.hostname in all cases */
+        *hostname = kstrndup(dev_name, len, GFP_KERNEL);
+        if (!*hostname)
+                goto out_nomem;
+
+        /* kill possible hostname list: not supported */
+        comma = strchr(*hostname, ',');
+        if (comma != NULL) {
+                if (comma == *hostname)
+                        goto out_bad_devname;
+                *comma = '\0';
+        }
+
+        colon++;
+        len = strlen(colon);
+        if (len > maxpathlen)
+                goto out_path;
+        *export_path = kstrndup(colon, len, GFP_KERNEL);
+        if (!*export_path)
+                goto out_nomem;
+
+        dfprintk(MOUNT, "NFS: MNTPATH: '%s'\n", *export_path);
+        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;
+}
+
+/*
  * Validate the NFS2/NFS3 mount data
  * - fills in the mount root filehandle
  *
@@ -1323,8 +1384,6 @@ static int nfs_validate_mount_data(void *options,
 
                 break;
         default: {
-                unsigned int len;
-                char *c;
                 int status;
 
                 if (nfs_parse_mount_options((char *)options, args) == 0)
@@ -1334,21 +1393,17 @@ static int nfs_validate_mount_data(void *options,
                                                 &args->nfs_server.address))
                         goto out_no_address;
 
-                c = strchr(dev_name, ':');
-                if (c == NULL)
-                        return -EINVAL;
-                len = c - dev_name;
-                /* N.B. caller will free nfs_server.hostname in all cases */
-                args->nfs_server.hostname = kstrndup(dev_name, len, GFP_KERNEL);
-                if (!args->nfs_server.hostname)
-                        goto out_nomem;
+                status = nfs_parse_devname(dev_name,
+                                           &args->nfs_server.hostname,
+                                           PAGE_SIZE,
+                                           &args->nfs_server.export_path,
+                                           NFS_MAXPATHLEN);
+                if (!status)
+                        status = nfs_try_mount(args, mntfh);
 
-                c++;
-                if (strlen(c) > NFS_MAXPATHLEN)
-                        return -ENAMETOOLONG;
-                args->nfs_server.export_path = c;
+                kfree(args->nfs_server.export_path);
+                args->nfs_server.export_path = NULL;
 
-                status = nfs_try_mount(args, mntfh);
                 if (status)
                         return status;
 
@@ -1958,7 +2013,7 @@ static int nfs4_validate_mount_data(void *options,
 
                 break;
         default: {
-                unsigned int len;
+                int status;
 
                 if (nfs_parse_mount_options((char *)options, args) == 0)
                         return -EINVAL;
@@ -1977,34 +2032,17 @@ static int nfs4_validate_mount_data(void *options,
                         goto out_inval_auth;
                 }
 
-                /*
-                 * Split "dev_name" into "hostname:mntpath".
-                 */
-                c = strchr(dev_name, ':');
-                if (c == NULL)
-                        return -EINVAL;
-                /* while calculating len, pretend ':' is '\0' */
-                len = c - dev_name;
-                if (len > NFS4_MAXNAMLEN)
-                        return -ENAMETOOLONG;
-                /* N.B. caller will free nfs_server.hostname in all cases */
-                args->nfs_server.hostname = kstrndup(dev_name, len, GFP_KERNEL);
-                if (!args->nfs_server.hostname)
-                        goto out_nomem;
-
-                c++;                    /* step over the ':' */
-                len = strlen(c);
-                if (len > NFS4_MAXPATHLEN)
-                        return -ENAMETOOLONG;
-                args->nfs_server.export_path = kstrndup(c, len, GFP_KERNEL);
-                if (!args->nfs_server.export_path)
-                        goto out_nomem;
-
-                dprintk("NFS: MNTPATH: '%s'\n", args->nfs_server.export_path);
-
                 if (args->client_address == NULL)
                         goto out_no_client_address;
 
+                status = nfs_parse_devname(dev_name,
+                                           &args->nfs_server.hostname,
+                                           NFS4_MAXNAMLEN,
+                                           &args->nfs_server.export_path,
+                                           NFS4_MAXPATHLEN);
+                if (status < 0)
+                        return status;
+
                 break;
                 }
         }
@@ -2020,10 +2058,6 @@ out_inval_auth:
                  data->auth_flavourlen);
         return -EINVAL;
 
-out_nomem:
-        dfprintk(MOUNT, "NFS4: not enough memory to handle mount options\n");
-        return -ENOMEM;
-
 out_no_address:
         dfprintk(MOUNT, "NFS4: mount program didn't pass remote address\n");
         return -EINVAL;