On Tue 01-04-25 21:46:29, Amir Goldstein wrote:
> Used to subscribe for notifications for when mounts
> are attached/detached from a mount namespace.
>
> Cc: Jan Kara <jack@xxxxxxx>
> Cc: Miklos Szeredi <mszeredi@xxxxxxxxxx>
> Reviewed-by: Christian Brauner <brauner@xxxxxxxxxx>
> Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
Looks good. Feel free to add:
Reviewed-by: Jan Kara <jack@xxxxxxx>
Honza
> ---
>
> Changes since v1:
> - Add RVB
> - Add reference to statx() unique mnt_id (Jan)
> - Fix description of MARK_MNTNS path (Miklos)
>
> man/man2/fanotify_init.2 | 20 ++++++++++++++++++
> man/man2/fanotify_mark.2 | 35 +++++++++++++++++++++++++++++++-
> man/man7/fanotify.7 | 44 ++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 98 insertions(+), 1 deletion(-)
>
> diff --git a/man/man2/fanotify_init.2 b/man/man2/fanotify_init.2
> index 699b6f054..26289c496 100644
> --- a/man/man2/fanotify_init.2
> +++ b/man/man2/fanotify_init.2
> @@ -330,6 +330,26 @@ that the directory entry is referring to.
> This is a synonym for
> .RB ( FAN_REPORT_DFID_NAME | FAN_REPORT_FID | FAN_REPORT_TARGET_FID ).
> .TP
> +.BR FAN_REPORT_MNT " (since Linux 6.14)"
> +.\" commit 0f46d81f2bce970b1c562aa3c944a271bbec2729
> +This value allows the receipt of events which contain additional information
> +about the underlying mount correlated to an event.
> +An additional record of type
> +.B FAN_EVENT_INFO_TYPE_MNT
> +encapsulates the information about the mount and is included alongside the
> +generic event metadata structure.
> +The use of
> +.BR FAN_CLASS_CONTENT ,
> +.BR FAN_CLASS_PRE_CONTENT,
> +or any of the
> +.B FAN_REPORT_DFID_NAME_TARGET
> +flags along with this flag is not permitted
> +and will result in the error
> +.BR EINVAL .
> +See
> +.BR fanotify (7)
> +for additional details.
> +.TP
> .BR FAN_REPORT_PIDFD " (since Linux 5.15 and 5.10.220)"
> .\" commit af579beb666aefb17e9a335c12c788c92932baf1
> Events for fanotify groups initialized with this flag will contain
> diff --git a/man/man2/fanotify_mark.2 b/man/man2/fanotify_mark.2
> index da569279b..dab7e1a32 100644
> --- a/man/man2/fanotify_mark.2
> +++ b/man/man2/fanotify_mark.2
> @@ -67,7 +67,8 @@ contains
> all marks for filesystems are removed from the group.
> Otherwise, all marks for directories and files are removed.
> No flag other than, and at most one of, the flags
> -.B FAN_MARK_MOUNT
> +.BR FAN_MARK_MNTNS ,
> +.BR FAN_MARK_MOUNT ,
> or
> .B FAN_MARK_FILESYSTEM
> can be used in conjunction with
> @@ -99,6 +100,20 @@ If the filesystem object to be marked is not a directory, the error
> .B ENOTDIR
> shall be raised.
> .TP
> +.BR FAN_MARK_MNTNS " (since Linux 6.14)"
> +.\" commit 0f46d81f2bce970b1c562aa3c944a271bbec2729
> +Mark the mount namespace specified by
> +.IR pathname .
> +If the
> +.I pathname
> +is not a path that represents a mount namespace (e.g.
> +.BR /proc/ pid /ns/mnt ),
> +the call fails with the error
> +.BR EINVAL .
> +An fanotify group that is initialized with flag
> +.B FAN_REPORT_MNT
> +is required.
> +.TP
> .B FAN_MARK_MOUNT
> Mark the mount specified by
> .IR pathname .
> @@ -395,6 +410,24 @@ Create an event when a marked file or directory itself has been moved.
> An fanotify group that identifies filesystem objects by file handles
> is required.
> .TP
> +.BR FAN_MNT_ATTACH ", " FAN_MNT_DETACH " (since Linux 6.14)"
> +.\" commit 0f46d81f2bce970b1c562aa3c944a271bbec2729
> +Create an event when a mount was attached to or detached from a marked mount namespace.
> +An attempt to set this flag on an inode, mount or filesystem mark
> +will result in the error
> +.BR EINVAL .
> +An fanotify group that is initialized with flag
> +.B FAN_REPORT_MNT
> +and the mark flag
> +.B FAN_MARK_MNTNS
> +are required.
> +An additional information record of type
> +.B FAN_EVENT_INFO_TYPE_MNT
> +is returned with the event.
> +See
> +.BR fanotify (7)
> +for additional details.
> +.TP
> .BR FAN_FS_ERROR " (since Linux 5.16, 5.15.154, and 5.10.220)"
> .\" commit 9709bd548f11a092d124698118013f66e1740f9b
> Create an event when a filesystem error
> diff --git a/man/man7/fanotify.7 b/man/man7/fanotify.7
> index 77dcb8aa5..a2f766839 100644
> --- a/man/man7/fanotify.7
> +++ b/man/man7/fanotify.7
> @@ -228,6 +228,23 @@ struct fanotify_event_info_pidfd {
> .EE
> .in
> .P
> +In cases where an fanotify group is initialized with
> +.BR FAN_REPORT_MNT ,
> +event listeners should expect to receive the below
> +information record object alongside the generic
> +.I fanotify_event_metadata
> +structure within the read buffer.
> +This structure is defined as follows:
> +.P
> +.in +4n
> +.EX
> +struct fanotify_event_info_mnt {
> + struct fanotify_event_info_header hdr;
> + __u64 mnt_id;
> +};
> +.EE
> +.in
> +.P
> In case of a
> .B FAN_FS_ERROR
> event,
> @@ -442,6 +459,12 @@ A file or directory that was opened read-only
> .RB ( O_RDONLY )
> was closed.
> .TP
> +.BR FAN_MNT_ATTACH
> +A mount was attached to mount namespace.
> +.TP
> +.BR FAN_MNT_DETACH
> +A mount was detached from mount namespace.
> +.TP
> .B FAN_FS_ERROR
> A filesystem error was detected.
> .TP
> @@ -540,6 +563,7 @@ The value of this field can be set to one of the following:
> .BR FAN_EVENT_INFO_TYPE_FID ,
> .BR FAN_EVENT_INFO_TYPE_DFID ,
> .BR FAN_EVENT_INFO_TYPE_DFID_NAME ,
> +.BR FAN_EVENT_INFO_TYPE_MNT ,
> .BR FAN_EVENT_INFO_TYPE_ERROR ,
> .BR FAN_EVENT_INFO_TYPE_RANGE ,
> or
> @@ -727,6 +751,26 @@ in case of a terminated process, the value will be
> .BR \-ESRCH .
> .P
> The fields of the
> +.I fanotify_event_info_mnt
> +structure are as follows:
> +.TP
> +.I .hdr
> +This is a structure of type
> +.IR fanotify_event_info_header .
> +The
> +.I .info_type
> +field is set to
> +.BR FAN_EVENT_INFO_TYPE_MNT .
> +.TP
> +.I .mnt_id
> +Identifies the mount associated with the event.
> +It is a 64bit unique mount id as the one returned by
> +.BR statx (2)
> +with the
> +.BR STATX_MNT_ID_UNIQUE
> +flag.
> +.P
> +The fields of the
> .I fanotify_event_info_error
> structure are as follows:
> .TP
> --
> 2.34.1
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
