9p: xattr simplifications

Now that the xattr handler is passed to the xattr handler operations, we
can use the same get and set operations for the user, trusted, and security
xattr namespaces.  In those namespaces, we can access the full attribute
name by "reattaching" the name prefix the vfs has skipped for us.  Add a
xattr_full_name helper to make this obvious in the code.

For the "system.posix_acl_access" and "system.posix_acl_default"
attributes, handler->prefix is the full attribute name; the suffix is the
empty string.

Signed-off-by: Andreas Gruenbacher <[email protected]>
Cc: Eric Van Hensbergen <[email protected]>
Cc: Ron Minnich <[email protected]>
Cc: Latchesar Ionkov <[email protected]>
Cc: [email protected]
Signed-off-by: Al Viro <[email protected]>

fs/9p/Makefile

@@ -10,10 +10,7 @@ obj-$(CONFIG_9P_FS) := 9p.o
 	vfs_dentry.o \
 	v9fs.o \
 	fid.o  \
-	xattr.o \
-	xattr_user.o \
-	xattr_trusted.o
+	xattr.o
 
 9p-$(CONFIG_9P_FSCACHE) += cache.o
 9p-$(CONFIG_9P_FS_POSIX_ACL) += acl.o
-9p-$(CONFIG_9P_FS_SECURITY) += xattr_security.o

fs/9p/acl.c

@@ -212,31 +212,12 @@ int v9fs_acl_mode(struct inode *dir, umode_t *modep,
 	return 0;
 }
 
-static int v9fs_remote_get_acl(struct dentry *dentry, const char *name,
-			       void *buffer, size_t size, int type)
-{
-	char *full_name;
-
-	switch (type) {
-	case ACL_TYPE_ACCESS:
-		full_name =  POSIX_ACL_XATTR_ACCESS;
-		break;
-	case ACL_TYPE_DEFAULT:
-		full_name = POSIX_ACL_XATTR_DEFAULT;
-		break;
-	default:
-		BUG();
-	}
-	return v9fs_xattr_get(dentry, full_name, buffer, size);
-}
-
 static int v9fs_xattr_get_acl(const struct xattr_handler *handler,
 			      struct dentry *dentry, const char *name,
 			      void *buffer, size_t size)
 {
 	struct v9fs_session_info *v9ses;
 	struct posix_acl *acl;
-	int type = handler->flags;
 	int error;
 
 	if (strcmp(name, "") != 0)
@@ -247,9 +228,9 @@ static int v9fs_xattr_get_acl(const struct xattr_handler *handler,
 	 * We allow set/get/list of acl when access=client is not specified
 	 */
 	if ((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT)
-		return v9fs_remote_get_acl(dentry, name, buffer, size, type);
+		return v9fs_xattr_get(dentry, handler->prefix, buffer, size);
 
-	acl = v9fs_get_cached_acl(d_inode(dentry), type);
+	acl = v9fs_get_cached_acl(d_inode(dentry), handler->flags);
 	if (IS_ERR(acl))
 		return PTR_ERR(acl);
 	if (acl == NULL)
@@ -260,26 +241,6 @@ static int v9fs_xattr_get_acl(const struct xattr_handler *handler,
 	return error;
 }
 
-static int v9fs_remote_set_acl(struct dentry *dentry, const char *name,
-			      const void *value, size_t size,
-			      int flags, int type)
-{
-	char *full_name;
-
-	switch (type) {
-	case ACL_TYPE_ACCESS:
-		full_name =  POSIX_ACL_XATTR_ACCESS;
-		break;
-	case ACL_TYPE_DEFAULT:
-		full_name = POSIX_ACL_XATTR_DEFAULT;
-		break;
-	default:
-		BUG();
-	}
-	return v9fs_xattr_set(dentry, full_name, value, size, flags);
-}
-
-
 static int v9fs_xattr_set_acl(const struct xattr_handler *handler,
 			      struct dentry *dentry, const char *name,
 			      const void *value, size_t size, int flags)
@@ -298,8 +259,8 @@ static int v9fs_xattr_set_acl(const struct xattr_handler *handler,
 	 * xattr value. We leave it to the server to validate
 	 */
 	if ((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT)
-		return v9fs_remote_set_acl(dentry, name,
-					   value, size, flags, handler->flags);
+		return v9fs_xattr_set(dentry, handler->prefix, value, size,
+				      flags);
 
 	if (S_ISLNK(inode->i_mode))
 		return -EOPNOTSUPP;
@@ -320,7 +281,6 @@ static int v9fs_xattr_set_acl(const struct xattr_handler *handler,
 
 	switch (handler->flags) {
 	case ACL_TYPE_ACCESS:
-		name = POSIX_ACL_XATTR_ACCESS;
 		if (acl) {
 			umode_t mode = inode->i_mode;
 			retval = posix_acl_equiv_mode(acl, &mode);
@@ -351,7 +311,6 @@ static int v9fs_xattr_set_acl(const struct xattr_handler *handler,
 		}
 		break;
 	case ACL_TYPE_DEFAULT:
-		name = POSIX_ACL_XATTR_DEFAULT;
 		if (!S_ISDIR(inode->i_mode)) {
 			retval = acl ? -EINVAL : 0;
 			goto err_out;
@@ -360,7 +319,7 @@ static int v9fs_xattr_set_acl(const struct xattr_handler *handler,
 	default:
 		BUG();
 	}
-	retval = v9fs_xattr_set(dentry, name, value, size, flags);
+	retval = v9fs_xattr_set(dentry, handler->prefix, value, size, flags);
 	if (!retval)
 		set_cached_acl(inode, handler->flags, acl);
 err_out:

fs/9p/xattr.c

@@ -137,6 +137,48 @@ ssize_t v9fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
 	return v9fs_xattr_get(dentry, NULL, buffer, buffer_size);
 }
 
+static int v9fs_xattr_handler_get(const struct xattr_handler *handler,
+				  struct dentry *dentry, const char *name,
+				  void *buffer, size_t size)
+{
+	const char *full_name = xattr_full_name(handler, name);
+
+	if (strcmp(name, "") == 0)
+		return -EINVAL;
+	return v9fs_xattr_get(dentry, full_name, buffer, size);
+}
+
+static int v9fs_xattr_handler_set(const struct xattr_handler *handler,
+				  struct dentry *dentry, const char *name,
+				  const void *value, size_t size, int flags)
+{
+	const char *full_name = xattr_full_name(handler, name);
+
+	if (strcmp(name, "") == 0)
+		return -EINVAL;
+	return v9fs_xattr_set(dentry, full_name, value, size, flags);
+}
+
+static struct xattr_handler v9fs_xattr_user_handler = {
+	.prefix	= XATTR_USER_PREFIX,
+	.get	= v9fs_xattr_handler_get,
+	.set	= v9fs_xattr_handler_set,
+};
+
+static struct xattr_handler v9fs_xattr_trusted_handler = {
+	.prefix	= XATTR_TRUSTED_PREFIX,
+	.get	= v9fs_xattr_handler_get,
+	.set	= v9fs_xattr_handler_set,
+};
+
+#ifdef CONFIG_9P_FS_SECURITY
+static struct xattr_handler v9fs_xattr_security_handler = {
+	.prefix	= XATTR_SECURITY_PREFIX,
+	.get	= v9fs_xattr_handler_get,
+	.set	= v9fs_xattr_handler_set,
+};
+#endif
+
 const struct xattr_handler *v9fs_xattr_handlers[] = {
 	&v9fs_xattr_user_handler,
 	&v9fs_xattr_trusted_handler,

fs/9p/xattr.h

@@ -19,9 +19,6 @@
 #include <net/9p/client.h>
 
 extern const struct xattr_handler *v9fs_xattr_handlers[];
-extern struct xattr_handler v9fs_xattr_user_handler;
-extern struct xattr_handler v9fs_xattr_trusted_handler;
-extern struct xattr_handler v9fs_xattr_security_handler;
 extern const struct xattr_handler v9fs_xattr_acl_access_handler;
 extern const struct xattr_handler v9fs_xattr_acl_default_handler;