Index: head/lib/libc/sys/posix_fallocate.2
===================================================================
--- head/lib/libc/sys/posix_fallocate.2
+++ head/lib/libc/sys/posix_fallocate.2
@@ -28,7 +28,7 @@
 .\"     @(#)open.2	8.2 (Berkeley) 11/16/93
 .\" $FreeBSD$
 .\"
-.Dd January 23, 2014
+.Dd October 12, 2017
 .Dt POSIX_FALLOCATE 2
 .Os
 .Sh NAME
@@ -118,6 +118,10 @@
 .It Bq Er ENOSPC
 There is insufficient free space remaining on the file system storage
 media.
+.It Bq Er ENOTCAPABLE
+The file descriptor
+.Fa fd
+has insufficient rights.
 .It Bq Er ESPIPE
 The
 .Fa fd
Index: head/sys/kern/capabilities.conf
===================================================================
--- head/sys/kern/capabilities.conf
+++ head/sys/kern/capabilities.conf
@@ -488,6 +488,7 @@
 ##
 ## Allow I/O-related file descriptors, subject to capability rights.
 ##
+posix_fallocate
 pread
 preadv
 
Index: head/sys/kern/vfs_syscalls.c
===================================================================
--- head/sys/kern/vfs_syscalls.c
+++ head/sys/kern/vfs_syscalls.c
@@ -4400,7 +4400,7 @@
 	if (offset > OFF_MAX - len)
 		return (EFBIG);
 	AUDIT_ARG_FD(fd);
-	error = fget(td, fd, cap_rights_init(&rights, CAP_WRITE), &fp);
+	error = fget(td, fd, cap_rights_init(&rights, CAP_PWRITE), &fp);
 	if (error != 0)
 		return (error);
 	AUDIT_ARG_FILE(td->td_proc, fp);