From: David Howells <dhowells@redhat.com>
To: Amir Goldstein <amir73il@gmail.com>
Cc: dhowells@redhat.com, Jan Kara <jack@suse.cz>,
Al Viro <viro@zeniv.linux.org.uk>, Ian Kent <raven@themaw.net>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
linux-api@vger.kernel.org,
linux-block <linux-block@vger.kernel.org>,
keyrings@vger.kernel.org,
LSM List <linux-security-module@vger.kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [RFC][PATCH 0/7] Mount, FS, Block and Keyrings notifications
Date: Tue, 04 Jun 2019 13:33:01 +0100 [thread overview]
Message-ID: <16167.1559651581@warthog.procyon.org.uk> (raw)
In-Reply-To: <CAOQ4uxjLzURf8c1UH_xCJKkuD2es8i-=P-ZNM=t3aFcZLMwXEg@mail.gmail.com>
Amir Goldstein <amir73il@gmail.com> wrote:
> Well I am sure that ring buffer for fanotify events would be useful, so
> seeing that David is proposing a generic notification mechanism, I wanted
> to know how that mechanism could best share infrastructure with fsnotify.
>
> But apart from that I foresee the questions from users about why the
> mount notification API and filesystem events API do not have better
> integration.
>
> The way I see it, the notification queue can serve several classes
> of notifications and fsnotify could be one of those classes
> (at least FAN_CLASS_NOTIF fits nicely to the model).
It could be done; the main thing that concerns me is that the buffer is of
limited capacity.
However, I could take this:
struct fanotify_event_metadata {
__u32 event_len;
__u8 vers;
__u8 reserved;
__u16 metadata_len;
__aligned_u64 mask;
__s32 fd;
__s32 pid;
};
and map it to:
struct fanotify_notification {
struct watch_notification watch; /* WATCH_TYPE_FANOTIFY */
__aligned_u64 mask;
__u16 metadata_len;
__u8 vers;
__u8 reserved;
__u32 reserved2;
__s32 fd;
__s32 pid;
};
and some of the watch::info bit could be used:
n->watch.info & WATCH_INFO_OVERRUN watch queue overran
n->watch.info & WATCH_INFO_LENGTH event_len
n->watch.info & WATCH_INFO_RECURSIVE FAN_EVENT_ON_CHILD
n->watch.info & WATCH_INFO_FLAG_0 FAN_*_PERM
n->watch.info & WATCH_INFO_FLAG_1 FAN_Q_OVERFLOW
n->watch.info & WATCH_INFO_FLAG_2 FAN_ON_DIR
n->subtype ffs(n->mask)
Ideally, I'd dispense with metadata_len, vers, reserved* and set the version
when setting the watch.
fanotify_watch(int watchfd, unsigned int flags, u64 *mask,
int dirfd, const char *pathname, unsigned int at_flags);
We might also want to extend the watch_filter to allow you to, say, filter on
the first __u64 after the watch member so that you could filter on specific
events:
struct watch_notification_type_filter {
__u32 type;
__u32 info_filter;
__u32 info_mask;
__u32 subtype_filter[8];
__u64 payload_mask[1];
__u64 payload_set[1];
};
So, in this case, it would require:
n->mask & wf->payload_mask[0] == wf->payload_set[0]
to be true to record the message.
David
next prev parent reply other threads:[~2019-06-04 12:33 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-28 16:01 [RFC][PATCH 0/7] Mount, FS, Block and Keyrings notifications David Howells
2019-05-28 16:01 ` [PATCH 1/7] General notification queue with user mmap()'able ring buffer David Howells
2019-05-28 16:26 ` Greg KH
2019-05-28 17:30 ` David Howells
2019-05-28 23:12 ` Greg KH
2019-05-29 16:06 ` David Howells
2019-05-29 17:46 ` Jann Horn
2019-05-29 21:02 ` David Howells
2019-05-31 11:14 ` Peter Zijlstra
2019-05-31 12:02 ` David Howells
2019-05-31 13:26 ` Peter Zijlstra
2019-05-31 14:20 ` David Howells
2019-05-31 16:44 ` Peter Zijlstra
2019-05-31 17:12 ` David Howells
2019-06-17 16:24 ` Peter Zijlstra
2019-05-29 23:09 ` Greg KH
2019-05-29 23:11 ` Greg KH
2019-05-30 9:50 ` Andrea Parri
2019-05-31 8:35 ` Peter Zijlstra
2019-05-31 8:47 ` Peter Zijlstra
2019-05-31 12:42 ` David Howells
2019-05-31 14:55 ` David Howells
2019-05-28 19:14 ` Jann Horn
2019-05-28 22:28 ` David Howells
2019-05-28 23:16 ` Jann Horn
2019-05-28 16:02 ` [PATCH 2/7] keys: Add a notification facility David Howells
2019-05-28 16:02 ` [PATCH 3/7] vfs: Add a mount-notification facility David Howells
2019-05-28 20:06 ` Jann Horn
2019-05-28 23:04 ` David Howells
2019-05-28 23:23 ` Jann Horn
2019-05-29 11:16 ` David Howells
2019-05-28 23:08 ` David Howells
2019-05-29 10:55 ` David Howells
2019-05-29 11:00 ` David Howells
2019-05-29 15:53 ` Casey Schaufler
2019-05-29 16:12 ` Jann Horn
2019-05-29 17:04 ` Casey Schaufler
2019-06-03 16:30 ` David Howells
2019-05-29 17:13 ` Andy Lutomirski
2019-05-29 17:46 ` Casey Schaufler
2019-05-29 18:11 ` Jann Horn
2019-05-29 19:28 ` Casey Schaufler
2019-05-29 19:47 ` Jann Horn
2019-05-29 20:50 ` Casey Schaufler
2019-05-29 23:12 ` Andy Lutomirski
2019-05-29 23:56 ` Casey Schaufler
2019-05-28 16:02 ` [PATCH 4/7] vfs: Add superblock notifications David Howells
2019-05-28 20:27 ` Jann Horn
2019-05-29 12:58 ` David Howells
2019-05-29 14:16 ` Jann Horn
2019-05-28 16:02 ` [PATCH 5/7] fsinfo: Export superblock notification counter David Howells
2019-05-28 16:02 ` [PATCH 6/7] block: Add block layer notifications David Howells
2019-05-28 20:37 ` Jann Horn
2019-05-28 16:02 ` [PATCH 7/7] Add sample notification program David Howells
2019-05-28 23:58 ` [RFC][PATCH 0/7] Mount, FS, Block and Keyrings notifications Greg KH
2019-05-29 6:33 ` Amir Goldstein
2019-05-29 14:25 ` Jan Kara
2019-05-29 15:10 ` Greg KH
2019-05-29 15:53 ` Amir Goldstein
2019-05-30 11:00 ` Jan Kara
2019-06-04 12:33 ` David Howells [this message]
2019-05-29 6:45 ` David Howells
2019-05-29 7:40 ` Amir Goldstein
2019-05-29 9:09 ` David Howells
2019-05-29 15:41 ` Casey Schaufler
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