@@ -134,6 +134,33 @@ xattr_permission(struct inode *inode, const char *name, int mask)
return inode_permission(inode, mask);
}
+/*
+ * Look for any handler that deals with the specified namespace.
+ */
+int
+xattr_supported_namespace(struct inode *inode, const char *prefix)
+{
+ const struct xattr_handler **handlers = inode->i_sb->s_xattr;
+ const struct xattr_handler *handler;
+ size_t preflen;
+
+ if (!(inode->i_opflags & IOP_XATTR)) {
+ if (unlikely(is_bad_inode(inode)))
+ return -EIO;
+ return -EOPNOTSUPP;
+ }
+
+ preflen = strlen(prefix);
+
+ for_each_xattr_handler(handlers, handler) {
+ if (!strncmp(xattr_prefix(handler), prefix, preflen))
+ return 0;
+ }
+
+ return -EOPNOTSUPP;
+}
+EXPORT_SYMBOL(xattr_supported_namespace);
+
int
__vfs_setxattr(struct dentry *dentry, struct inode *inode, const char *name,
const void *value, size_t size, int flags)
@@ -61,6 +61,8 @@ ssize_t generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_siz
ssize_t vfs_getxattr_alloc(struct dentry *dentry, const char *name,
char **xattr_value, size_t size, gfp_t flags);
+int xattr_supported_namespace(struct inode *inode, const char *prefix);
+
static inline const char *xattr_prefix(const struct xattr_handler *handler)
{
return handler->prefix ?: handler->name;
Add a function that checks is an extended attribute namespace is supported for an inode, meaning that a handler must be present for either the whole namespace, or at least one synthetic xattr in the namespace. To be used by the nfs server code when being queried for extended attributes support. Cc: linux-fsdevel@vger.kernel.org Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Frank van der Linden <fllinden@amazon.com> --- fs/xattr.c | 27 +++++++++++++++++++++++++++ include/linux/xattr.h | 2 ++ 2 files changed, 29 insertions(+)