[PATCH v2 3/3] fanotify.7: Document FAN_DENY_ERRNO()

[Amir Goldstein <amir73il@gmail.com>]

Document FAN_DENY_ERRNO(), that was added in v6.13 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>
---

Changes since v1:
- Split out to 3 patches
- Add example of FAN_DENY_ERRNO

 man/man7/fanotify.7 | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/man/man7/fanotify.7 b/man/man7/fanotify.7
index 863578bd7..a532a963a 100644
--- 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
+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
-- 
2.34.1