diff --git a/man7/attr.7 b/man7/attr.7
index 491482de3..75379e697 100644
--- a/man7/attr.7
+++ b/man7/attr.7
@@ -155,6 +155,12 @@ attribute information on disk are scalable.
 
 In the JFS, XFS, and Reiserfs filesystem implementations,
 the limit on bytes used in an EA value is the ceiling imposed by the VFS.
+
+In the Btrfs filesystem implementation,
+the total bytes used for the name, value, and implementation overhead bytes
+is limited to the filesystem
+.I nodesize
+value (16kB by default).
 .SH CONFORMING TO
 Extended attributes are not specified in POSIX.1, but some other systems
 (e.g., the BSDs and Solaris) provide a similar feature.