NFS: Add final pieces to support in-kernel mount option parsing

Hook in final components required for supporting in-kernel mount option
parsing for NFSv2 and NFSv3 mounts.

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

diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index 48db52a..757aa3b 100644 (file)
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -1051,10 +1051,28 @@ out_err:
 /*
  * Validate the NFS2/NFS3 mount data
  * - fills in the mount root filehandle
+ *
+ * For option strings, user space handles the following behaviors:
+ *
+ * + DNS: mapping server host name to IP address ("addr=" option)
+ *
+ * + failure mode: how to behave if a mount request can't be handled
+ *   immediately ("fg/bg" option)
+ *
+ * + retry: how often to retry a mount request ("retry=" option)
+ *
+ * + breaking back: trying proto=udp after proto=tcp, v2 after v3,
+ *   mountproto=tcp after mountproto=udp, and so on
+ *
+ * XXX: as far as I can tell, changing the NFS program number is not
+ *      supported in the NFS client.
  */
-static int nfs_validate_mount_data(struct nfs_mount_data *data,
-                                  struct nfs_fh *mntfh)
+static int nfs_validate_mount_data(struct nfs_mount_data **options,
+                                  struct nfs_fh *mntfh,
+                                  const char *dev_name)
 {
+       struct nfs_mount_data *data = *options;
+
        if (data == NULL)
                goto out_no_data;
 
@@ -1087,8 +1105,78 @@ static int nfs_validate_mount_data(struct nfs_mount_data *data,
                        memset(mntfh->data + mntfh->size, 0,
                               sizeof(mntfh->data) - mntfh->size);
                break;
-       default:
-               goto out_bad_version;
+       default: {
+               unsigned int len;
+               char *c;
+               int status;
+               struct nfs_parsed_mount_data args = {
+                       .flags          = (NFS_MOUNT_VER3 | NFS_MOUNT_TCP),
+                       .rsize          = NFS_MAX_FILE_IO_SIZE,
+                       .wsize          = NFS_MAX_FILE_IO_SIZE,
+                       .timeo          = 600,
+                       .retrans        = 2,
+                       .acregmin       = 3,
+                       .acregmax       = 60,
+                       .acdirmin       = 30,
+                       .acdirmax       = 60,
+                       .mount_server.protocol = IPPROTO_UDP,
+                       .mount_server.program = NFS_MNT_PROGRAM,
+                       .nfs_server.protocol = IPPROTO_TCP,
+                       .nfs_server.program = NFS_PROGRAM,
+               };
+
+               if (nfs_parse_mount_options((char *) *options, &args) == 0)
+                       return -EINVAL;
+
+               data = kzalloc(sizeof(*data), GFP_KERNEL);
+               if (data == NULL)
+                       return -ENOMEM;
+
+               /*
+                * NB: after this point, caller will free "data"
+                * if we return an error
+                */
+               *options = data;
+
+               c = strchr(dev_name, ':');
+               if (c == NULL)
+                       return -EINVAL;
+               len = c - dev_name - 1;
+               if (len > sizeof(data->hostname))
+                       return -EINVAL;
+               strncpy(data->hostname, dev_name, len);
+               args.nfs_server.hostname = data->hostname;
+
+               c++;
+               if (strlen(c) > NFS_MAXPATHLEN)
+                       return -EINVAL;
+               args.nfs_server.export_path = c;
+
+               status = nfs_try_mount(&args, mntfh);
+               if (status)
+                       return -EINVAL;
+
+               /*
+                * Translate to nfs_mount_data, which nfs_fill_super
+                * can deal with.
+                */
+               data->version           = 6;
+               data->flags             = args.flags;
+               data->rsize             = args.rsize;
+               data->wsize             = args.wsize;
+               data->timeo             = args.timeo;
+               data->retrans           = args.retrans;
+               data->acregmin          = args.acregmin;
+               data->acregmax          = args.acregmax;
+               data->acdirmin          = args.acdirmin;
+               data->acdirmax          = args.acdirmax;
+               data->addr              = args.nfs_server.address;
+               data->namlen            = args.namlen;
+               data->bsize             = args.bsize;
+               data->pseudoflavor      = args.auth_flavors[0];
+
+               break;
+               }
        }
 
        if (!(data->flags & NFS_MOUNT_SECFLAVOUR))
@@ -1117,11 +1205,6 @@ out_no_sec:
        dfprintk(MOUNT, "NFS: nfs_mount_data version supports only AUTH_SYS\n");
        return -EINVAL;
 
-out_bad_version:
-       dfprintk(MOUNT, "NFS: bad nfs_mount_data version %d\n",
-                data->version);
-       return -EINVAL;
-
 #ifndef CONFIG_NFS_V3
 out_v3_not_compiled:
        dfprintk(MOUNT, "NFS: NFSv3 is not compiled into kernel\n");
@@ -1242,7 +1325,7 @@ static int nfs_get_sb(struct file_system_type *fs_type,
        int error;
 
        /* Validate the mount data */
-       error = nfs_validate_mount_data(data, &mntfh);
+       error = nfs_validate_mount_data(&data, &mntfh, dev_name);
        if (error < 0)
                goto out;
 
@@ -1283,6 +1366,8 @@ static int nfs_get_sb(struct file_system_type *fs_type,
        error = 0;
 
 out:
+       if (data != raw_data)
+               kfree(data);
        return error;
 
 out_err_nosb: