man/man7/fanotify.7: Document FAN_DENY_ERRNO()

Document FAN_DENY_ERRNO(), which was added in Linux 6.13 to
report specific errors on file access.

Cc: Jan Kara <jack@suse.cz>
Cc: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Message-ID: <20250331082759.1424401-3-amir73il@gmail.com>
Signed-off-by: Alejandro Colomar <alx@kernel.org>

diff --git a/man/man7/fanotify.7 b/man/man7/fanotify.7
index ad864b762a510d69a5361f63849b5da1e87a602e..156e4c35f48196fad96d4a2d560f3fe35ee4c532 100644 (file)
--- a/man/man7/fanotify.7
+++ b/man/man7/fanotify.7
@@ -778,6 +778,28 @@ to deny the file operation.
 If access is denied, the requesting application call will receive an
 .B EPERM
 error.
+Since Linux 6.13,
+.\" commit b4b2ff4f61ded819bfa22e50fdec7693f51cbbee
+if a notification group is initialized with class
+.BR FAN_CLASS_PRE_CONTENT ,
+the file operation can be denied with errors other than
+.BR EPERM .
+For example, for the requesting application to get the
+.B EIO
+error, the event listener can write the response
+.BR FAN_DENY_ERRNO ( EIO ).
+At the time of writing,
+only the following error values could be returned to the application with
+.BR FAN_DENY_ERRNO (\f[I]e\f[])
+macro:
+.BR EPERM ,
+.BR EIO ,
+.BR EBUSY ,
+.BR ETXTBSY ,
+.BR EAGAIN ,
+.BR ENOSPC ,
+.BR EDQUOT .
+.P
 Additionally, if the notification group has been created with the
 .B FAN_ENABLE_AUDIT
 flag, then the