[PATCH 1/4] mount_setattr.2: add and explain missing EBUSY error

[Christian Brauner <brauner@kernel.org>]

In order to ID-map a mount it must not have any writers. If the mount
has writers and the caller tries to ID-map the mount EBUSY will be
returned.

Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
---
 man2/mount_setattr.2 | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/man2/mount_setattr.2 b/man2/mount_setattr.2
index 77233f589..2bf1b24da 100644
--- a/man2/mount_setattr.2
+++ b/man2/mount_setattr.2
@@ -429,6 +429,13 @@ The caller tried to change the mount to
 .BR MOUNT_ATTR_RDONLY ,
 but the mount still holds files open for writing.
 .TP
+.B EBUSY
+The caller tried to create an ID-mapped mount raising
+.BR MOUNT_ATTR_IDMAP
+and specifying
+.I userns_fd
+but the mount still holds files open for writing.
+.TP
 .B EINVAL
 The pathname specified via the
 .I dirfd
@@ -662,6 +669,9 @@ This also implies that the ID mapping of a mount cannot be altered.
 The mount must be a detached mount;
 that is,
 it must have been created by calling
+.IP \(bu
+The mount must not have any writers.
+.\" commit 1bbcd277a53e08d619ffeec56c5c9287f2bf42f
 .BR open_tree (2)
 with the
 .B OPEN_TREE_CLONE
-- 
2.34.1