cifs: In the new mount api we get the full devname as source=

so we no longer need to handle or parse the UNC= and prefixpath=
options that mount.cifs are generating.

This also fixes a bug in the mount command option where the devname
would be truncated into just //server/share because we were looking
at the truncated UNC value and not the full path.

I.e.  in the mount command output the devive //server/share/path
would show up as just //server/share

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Shyam Prasad N <nspmangalore@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

Author: Ronnie Sahlberg

fs/cifs/cifsfs.c

@@ -469,7 +469,7 @@ cifs_show_cache_flavor(struct seq_file *s, struct cifs_sb_info *cifs_sb)
 static int cifs_show_devname(struct seq_file *m, struct dentry *root)
 {
 	struct cifs_sb_info *cifs_sb = CIFS_SB(root->d_sb);
-	char *devname = kstrdup(cifs_sb->ctx->UNC, GFP_KERNEL);
+	char *devname = kstrdup(cifs_sb->ctx->source, GFP_KERNEL);
 
 	if (devname == NULL)
 		seq_puts(m, "none");

fs/cifs/fs_context.c

@@ -148,7 +148,6 @@ const struct fs_parameter_spec smb3_fs_parameters[] = {
 
 	/* Mount options which take string value */
 	fsparam_string("source", Opt_source),
-	fsparam_string("unc", Opt_source),
 	fsparam_string("user", Opt_user),
 	fsparam_string("username", Opt_user),
 	fsparam_string("pass", Opt_pass),
@@ -178,6 +177,11 @@ const struct fs_parameter_spec smb3_fs_parameters[] = {
 	fsparam_flag_no("auto", Opt_ignore),
 	fsparam_string("cred", Opt_ignore),
 	fsparam_string("credentials", Opt_ignore),
+	/*
+	 * UNC and prefixpath is now extracted from Opt_source
+	 * in the new mount API so we can just ignore them going forward.
+	 */
+	fsparam_string("unc", Opt_ignore),
 	fsparam_string("prefixpath", Opt_ignore),
 	{}
 };
@@ -313,6 +317,7 @@ smb3_fs_context_dup(struct smb3_fs_context *new_ctx, struct smb3_fs_context *ctx
 	new_ctx->password = NULL;
 	new_ctx->domainname = NULL;
 	new_ctx->UNC = NULL;
+	new_ctx->source = NULL;
 	new_ctx->iocharset = NULL;
 
 	/*
@@ -323,6 +328,7 @@ smb3_fs_context_dup(struct smb3_fs_context *new_ctx, struct smb3_fs_context *ctx
 	DUP_CTX_STR(username);
 	DUP_CTX_STR(password);
 	DUP_CTX_STR(UNC);
+	DUP_CTX_STR(source);
 	DUP_CTX_STR(domainname);
 	DUP_CTX_STR(nodename);
 	DUP_CTX_STR(iocharset);
@@ -732,6 +738,7 @@ static int smb3_reconfigure(struct fs_context *fc)
 	 * just use what we already have in cifs_sb->ctx.
 	 */
 	STEAL_STRING(cifs_sb, ctx, UNC);
+	STEAL_STRING(cifs_sb, ctx, source);
 	STEAL_STRING(cifs_sb, ctx, username);
 	STEAL_STRING(cifs_sb, ctx, password);
 	STEAL_STRING(cifs_sb, ctx, domainname);
@@ -974,6 +981,11 @@ static int smb3_fs_context_parse_param(struct fs_context *fc,
 			cifs_dbg(VFS, "Unknown error parsing devname\n");
 			goto cifs_parse_mount_err;
 		}
+		ctx->source = kstrdup(param->string, GFP_KERNEL);
+		if (ctx->source == NULL) {
+			cifs_dbg(VFS, "OOM when copying UNC string\n");
+			goto cifs_parse_mount_err;
+		}
 		fc->source = kstrdup(param->string, GFP_KERNEL);
 		if (fc->source == NULL) {
 			cifs_dbg(VFS, "OOM when copying UNC string\n");
@@ -1396,6 +1408,8 @@ smb3_cleanup_fs_context_contents(struct smb3_fs_context *ctx)
 	ctx->password = NULL;
 	kfree(ctx->UNC);
 	ctx->UNC = NULL;
+	kfree(ctx->source);
+	ctx->source = NULL;
 	kfree(ctx->domainname);
 	ctx->domainname = NULL;
 	kfree(ctx->nodename);

fs/cifs/fs_context.h

@@ -159,6 +159,7 @@ struct smb3_fs_context {
 	char *username;
 	char *password;
 	char *domainname;
+	char *source;
 	char *UNC;
 	char *nodename;
 	char *iocharset;  /* local code page for mapping to and from Unicode */