* Kernel bugzilla 198569: fanotify_mark() and FAN_Q_OVERFLOW
@ 2020-04-23 10:36 Michael Kerrisk (man-pages)
2020-04-23 11:23 ` Jan Kara
0 siblings, 1 reply; 6+ messages in thread
From: Michael Kerrisk (man-pages) @ 2020-04-23 10:36 UTC (permalink / raw)
To: Heinrich Schuchardt
Cc: Amir Goldstein, linux-man, alexandermv, Matthew Bobrowski, Jan Kara
Hi Heinrich,
Would you be able to take a look at
https://bugzilla.kernel.org/show_bug.cgi?id=198569
It relates to some text you added to the fanotify_mark(2) manual page:
FAN_Q_OVERFLOW
Create an event when an overflow of the event queue occurs.
The size of the event queue is limited to 16384 entries if
FAN_UNLIMITED_QUEUE is not set in fanotify_init(2).
This was in the following commit
[[
commit 5d730f864a6603b090cd1078668cede05d02b8c4
Author: Heinrich Schuchardt <xypron.glpk@gmx.de>
Date: Tue Nov 8 23:13:38 2016 +0100
fanotify_mark.2: Mention FAN_Q_OVERFLOW
To receive overflow events it is necessary to set this bit
in fanotify_mark().
]]
As far as I can see, FAN_Q_OVERFLOW (test program, reading the kernel
source) is only an output flag. But on the other hand, I know you are
generally careful, so I wonder if something changed (though, at a
quick glance, I could not see evidence that it has).
Thanks,
Michael
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Kernel bugzilla 198569: fanotify_mark() and FAN_Q_OVERFLOW
2020-04-23 10:36 Kernel bugzilla 198569: fanotify_mark() and FAN_Q_OVERFLOW Michael Kerrisk (man-pages)
@ 2020-04-23 11:23 ` Jan Kara
2020-04-23 12:19 ` Amir Goldstein
0 siblings, 1 reply; 6+ messages in thread
From: Jan Kara @ 2020-04-23 11:23 UTC (permalink / raw)
To: Michael Kerrisk (man-pages)
Cc: Heinrich Schuchardt, Amir Goldstein, linux-man, alexandermv,
Matthew Bobrowski, Jan Kara
Hi Michael!
On Thu 23-04-20 12:36:26, Michael Kerrisk (man-pages) wrote:
> Would you be able to take a look at
> https://bugzilla.kernel.org/show_bug.cgi?id=198569
>
> It relates to some text you added to the fanotify_mark(2) manual page:
>
> FAN_Q_OVERFLOW
> Create an event when an overflow of the event queue occurs.
> The size of the event queue is limited to 16384 entries if
> FAN_UNLIMITED_QUEUE is not set in fanotify_init(2).
>
> This was in the following commit
>
> [[
> commit 5d730f864a6603b090cd1078668cede05d02b8c4
> Author: Heinrich Schuchardt <xypron.glpk@gmx.de>
> Date: Tue Nov 8 23:13:38 2016 +0100
>
> fanotify_mark.2: Mention FAN_Q_OVERFLOW
>
> To receive overflow events it is necessary to set this bit
> in fanotify_mark().
> ]]
>
> As far as I can see, FAN_Q_OVERFLOW (test program, reading the kernel
> source) is only an output flag. But on the other hand, I know you are
> generally careful, so I wonder if something changed (though, at a
> quick glance, I could not see evidence that it has).
Yeah, the manpage is wrong AFAICT. FAN_Q_OVERFLOW is not accepted in the
input mask. It is only output event flag.
Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Kernel bugzilla 198569: fanotify_mark() and FAN_Q_OVERFLOW
2020-04-23 11:23 ` Jan Kara
@ 2020-04-23 12:19 ` Amir Goldstein
2020-04-23 12:42 ` Michael Kerrisk (man-pages)
0 siblings, 1 reply; 6+ messages in thread
From: Amir Goldstein @ 2020-04-23 12:19 UTC (permalink / raw)
To: Jan Kara
Cc: Michael Kerrisk (man-pages),
Heinrich Schuchardt, linux-man, alexandermv, Matthew Bobrowski
On Thu, Apr 23, 2020 at 2:23 PM Jan Kara <jack@suse.cz> wrote:
>
> Hi Michael!
>
> On Thu 23-04-20 12:36:26, Michael Kerrisk (man-pages) wrote:
> > Would you be able to take a look at
> > https://bugzilla.kernel.org/show_bug.cgi?id=198569
> >
> > It relates to some text you added to the fanotify_mark(2) manual page:
> >
> > FAN_Q_OVERFLOW
> > Create an event when an overflow of the event queue occurs.
> > The size of the event queue is limited to 16384 entries if
> > FAN_UNLIMITED_QUEUE is not set in fanotify_init(2).
> >
> > This was in the following commit
> >
> > [[
> > commit 5d730f864a6603b090cd1078668cede05d02b8c4
> > Author: Heinrich Schuchardt <xypron.glpk@gmx.de>
> > Date: Tue Nov 8 23:13:38 2016 +0100
> >
> > fanotify_mark.2: Mention FAN_Q_OVERFLOW
> >
> > To receive overflow events it is necessary to set this bit
> > in fanotify_mark().
> > ]]
> >
> > As far as I can see, FAN_Q_OVERFLOW (test program, reading the kernel
> > source) is only an output flag. But on the other hand, I know you are
> > generally careful, so I wonder if something changed (though, at a
> > quick glance, I could not see evidence that it has).
>
> Yeah, the manpage is wrong AFAICT. FAN_Q_OVERFLOW is not accepted in the
> input mask. It is only output event flag.
>
Right.
Note that fanotify.7 documents FAN_Q_OVERFLOW as part of event output mask
so perhaps the FAN_Q_OVERFLOW entry for fanotify_mark.2 input mask should
just be removed?
Similarly, the input only flag FAN_EVENT_ON_CHILD is documented in
fanotify_mark.2, but not in fanotify.7.
FAN_ONDIR has been input only until v5.1 and since then it can also be
in output mask for group with FAN_REPORT_FID.
This is documented in fanotify_mark.2, but not in fanotify.7.
Thanks,
Amir.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Kernel bugzilla 198569: fanotify_mark() and FAN_Q_OVERFLOW
2020-04-23 12:19 ` Amir Goldstein
@ 2020-04-23 12:42 ` Michael Kerrisk (man-pages)
2020-04-23 16:42 ` Amir Goldstein
0 siblings, 1 reply; 6+ messages in thread
From: Michael Kerrisk (man-pages) @ 2020-04-23 12:42 UTC (permalink / raw)
To: Amir Goldstein
Cc: Jan Kara, Heinrich Schuchardt, linux-man, alexandermv, Matthew Bobrowski
Hello Amir, Jan,
On Thu, 23 Apr 2020 at 14:19, Amir Goldstein <amir73il@gmail.com> wrote:
>
> On Thu, Apr 23, 2020 at 2:23 PM Jan Kara <jack@suse.cz> wrote:
> >
> > Hi Michael!
> >
> > On Thu 23-04-20 12:36:26, Michael Kerrisk (man-pages) wrote:
> > > Would you be able to take a look at
> > > https://bugzilla.kernel.org/show_bug.cgi?id=198569
> > >
> > > It relates to some text you added to the fanotify_mark(2) manual page:
> > >
> > > FAN_Q_OVERFLOW
> > > Create an event when an overflow of the event queue occurs.
> > > The size of the event queue is limited to 16384 entries if
> > > FAN_UNLIMITED_QUEUE is not set in fanotify_init(2).
> > >
> > > This was in the following commit
> > >
> > > [[
> > > commit 5d730f864a6603b090cd1078668cede05d02b8c4
> > > Author: Heinrich Schuchardt <xypron.glpk@gmx.de>
> > > Date: Tue Nov 8 23:13:38 2016 +0100
> > >
> > > fanotify_mark.2: Mention FAN_Q_OVERFLOW
> > >
> > > To receive overflow events it is necessary to set this bit
> > > in fanotify_mark().
> > > ]]
> > >
> > > As far as I can see, FAN_Q_OVERFLOW (test program, reading the kernel
> > > source) is only an output flag. But on the other hand, I know you are
> > > generally careful, so I wonder if something changed (though, at a
> > > quick glance, I could not see evidence that it has).
> >
> > Yeah, the manpage is wrong AFAICT. FAN_Q_OVERFLOW is not accepted in the
> > input mask. It is only output event flag.
> >
>
> Right.
>
> Note that fanotify.7 documents FAN_Q_OVERFLOW as part of event output mask
> so perhaps the FAN_Q_OVERFLOW entry for fanotify_mark.2 input mask should
> just be removed?
Yes, I'll just remove that piece from fanotify_mark.2.
>
> Similarly, the input only flag FAN_EVENT_ON_CHILD is documented in
> fanotify_mark.2, but not in fanotify.7.
>
> FAN_ONDIR has been input only until v5.1 and since then it can also be
> in output mask for group with FAN_REPORT_FID.
> This is documented in fanotify_mark.2, but not in fanotify.7.
I'm overlooking something: where is this detail documented in
fanotify_mark.2? (I mean, I see mention of FAN_ONDIR, but no mention
of a change in v5.1.)
And would you be willing to write a small patch for fanotify.7 :-) ?
Thanks,
Michael
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Kernel bugzilla 198569: fanotify_mark() and FAN_Q_OVERFLOW
2020-04-23 12:42 ` Michael Kerrisk (man-pages)
@ 2020-04-23 16:42 ` Amir Goldstein
2020-05-15 11:44 ` Michael Kerrisk (man-pages)
0 siblings, 1 reply; 6+ messages in thread
From: Amir Goldstein @ 2020-04-23 16:42 UTC (permalink / raw)
To: Michael Kerrisk (man-pages)
Cc: Jan Kara, Heinrich Schuchardt, linux-man, alexandermv, Matthew Bobrowski
On Thu, Apr 23, 2020 at 3:42 PM Michael Kerrisk (man-pages)
<mtk.manpages@gmail.com> wrote:
>
> Hello Amir, Jan,
>
> On Thu, 23 Apr 2020 at 14:19, Amir Goldstein <amir73il@gmail.com> wrote:
> >
> > On Thu, Apr 23, 2020 at 2:23 PM Jan Kara <jack@suse.cz> wrote:
> > >
> > > Hi Michael!
> > >
> > > On Thu 23-04-20 12:36:26, Michael Kerrisk (man-pages) wrote:
> > > > Would you be able to take a look at
> > > > https://bugzilla.kernel.org/show_bug.cgi?id=198569
> > > >
> > > > It relates to some text you added to the fanotify_mark(2) manual page:
> > > >
> > > > FAN_Q_OVERFLOW
> > > > Create an event when an overflow of the event queue occurs.
> > > > The size of the event queue is limited to 16384 entries if
> > > > FAN_UNLIMITED_QUEUE is not set in fanotify_init(2).
> > > >
> > > > This was in the following commit
> > > >
> > > > [[
> > > > commit 5d730f864a6603b090cd1078668cede05d02b8c4
> > > > Author: Heinrich Schuchardt <xypron.glpk@gmx.de>
> > > > Date: Tue Nov 8 23:13:38 2016 +0100
> > > >
> > > > fanotify_mark.2: Mention FAN_Q_OVERFLOW
> > > >
> > > > To receive overflow events it is necessary to set this bit
> > > > in fanotify_mark().
> > > > ]]
> > > >
> > > > As far as I can see, FAN_Q_OVERFLOW (test program, reading the kernel
> > > > source) is only an output flag. But on the other hand, I know you are
> > > > generally careful, so I wonder if something changed (though, at a
> > > > quick glance, I could not see evidence that it has).
> > >
> > > Yeah, the manpage is wrong AFAICT. FAN_Q_OVERFLOW is not accepted in the
> > > input mask. It is only output event flag.
> > >
> >
> > Right.
> >
> > Note that fanotify.7 documents FAN_Q_OVERFLOW as part of event output mask
> > so perhaps the FAN_Q_OVERFLOW entry for fanotify_mark.2 input mask should
> > just be removed?
>
> Yes, I'll just remove that piece from fanotify_mark.2.
> >
> > Similarly, the input only flag FAN_EVENT_ON_CHILD is documented in
> > fanotify_mark.2, but not in fanotify.7.
> >
> > FAN_ONDIR has been input only until v5.1 and since then it can also be
> > in output mask for group with FAN_REPORT_FID.
> > This is documented in fanotify_mark.2, but not in fanotify.7.
>
> I'm overlooking something: where is this detail documented in
> fanotify_mark.2? (I mean, I see mention of FAN_ONDIR, but no mention
> of a change in v5.1.)
fanotify_mark.2:
The FAN_ONDIR flag is reported in an event mask only if the fanotify_fd
file descriptor has been initialized with the flag FAN_REPORT_FID.
fanotify_init.2:
FAN_REPORT_FID (since Linux 5.1)
>
> And would you be willing to write a small patch for fanotify.7 :-) ?
>
I guess I was asking for it ;-)
I have some more work cut out for me on this man page for v5.7 or later.
Adding yet another fanotify_init flag, so I'll make this change part of my
next series.
Thanks,
Amir.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Kernel bugzilla 198569: fanotify_mark() and FAN_Q_OVERFLOW
2020-04-23 16:42 ` Amir Goldstein
@ 2020-05-15 11:44 ` Michael Kerrisk (man-pages)
0 siblings, 0 replies; 6+ messages in thread
From: Michael Kerrisk (man-pages) @ 2020-05-15 11:44 UTC (permalink / raw)
To: Amir Goldstein
Cc: Jan Kara, Heinrich Schuchardt, linux-man, alexandermv, Matthew Bobrowski
On Thu, 23 Apr 2020 at 18:42, Amir Goldstein <amir73il@gmail.com> wrote:
>
> On Thu, Apr 23, 2020 at 3:42 PM Michael Kerrisk (man-pages)
> <mtk.manpages@gmail.com> wrote:
> >
> > Hello Amir, Jan,
> >
> > On Thu, 23 Apr 2020 at 14:19, Amir Goldstein <amir73il@gmail.com> wrote:
> > >
> > > On Thu, Apr 23, 2020 at 2:23 PM Jan Kara <jack@suse.cz> wrote:
> > > >
> > > > Hi Michael!
> > > >
> > > > On Thu 23-04-20 12:36:26, Michael Kerrisk (man-pages) wrote:
> > > > > Would you be able to take a look at
> > > > > https://bugzilla.kernel.org/show_bug.cgi?id=198569
> > > > >
> > > > > It relates to some text you added to the fanotify_mark(2) manual page:
> > > > >
> > > > > FAN_Q_OVERFLOW
> > > > > Create an event when an overflow of the event queue occurs.
> > > > > The size of the event queue is limited to 16384 entries if
> > > > > FAN_UNLIMITED_QUEUE is not set in fanotify_init(2).
> > > > >
> > > > > This was in the following commit
> > > > >
> > > > > [[
> > > > > commit 5d730f864a6603b090cd1078668cede05d02b8c4
> > > > > Author: Heinrich Schuchardt <xypron.glpk@gmx.de>
> > > > > Date: Tue Nov 8 23:13:38 2016 +0100
> > > > >
> > > > > fanotify_mark.2: Mention FAN_Q_OVERFLOW
> > > > >
> > > > > To receive overflow events it is necessary to set this bit
> > > > > in fanotify_mark().
> > > > > ]]
> > > > >
> > > > > As far as I can see, FAN_Q_OVERFLOW (test program, reading the kernel
> > > > > source) is only an output flag. But on the other hand, I know you are
> > > > > generally careful, so I wonder if something changed (though, at a
> > > > > quick glance, I could not see evidence that it has).
> > > >
> > > > Yeah, the manpage is wrong AFAICT. FAN_Q_OVERFLOW is not accepted in the
> > > > input mask. It is only output event flag.
> > > >
> > >
> > > Right.
> > >
> > > Note that fanotify.7 documents FAN_Q_OVERFLOW as part of event output mask
> > > so perhaps the FAN_Q_OVERFLOW entry for fanotify_mark.2 input mask should
> > > just be removed?
> >
> > Yes, I'll just remove that piece from fanotify_mark.2.
> > >
> > > Similarly, the input only flag FAN_EVENT_ON_CHILD is documented in
> > > fanotify_mark.2, but not in fanotify.7.
> > >
> > > FAN_ONDIR has been input only until v5.1 and since then it can also be
> > > in output mask for group with FAN_REPORT_FID.
> > > This is documented in fanotify_mark.2, but not in fanotify.7.
> >
> > I'm overlooking something: where is this detail documented in
> > fanotify_mark.2? (I mean, I see mention of FAN_ONDIR, but no mention
> > of a change in v5.1.)
>
> fanotify_mark.2:
> The FAN_ONDIR flag is reported in an event mask only if the fanotify_fd
> file descriptor has been initialized with the flag FAN_REPORT_FID.
>
> fanotify_init.2:
> FAN_REPORT_FID (since Linux 5.1)
>
> >
> > And would you be willing to write a small patch for fanotify.7 :-) ?
> >
>
> I guess I was asking for it ;-)
> I have some more work cut out for me on this man page for v5.7 or later.
> Adding yet another fanotify_init flag, so I'll make this change part of my
> next series.
Thanks, Amir. I look forward to the patch(es).
Cheers,
Michael
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2020-05-15 11:44 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-04-23 10:36 Kernel bugzilla 198569: fanotify_mark() and FAN_Q_OVERFLOW Michael Kerrisk (man-pages)
2020-04-23 11:23 ` Jan Kara
2020-04-23 12:19 ` Amir Goldstein
2020-04-23 12:42 ` Michael Kerrisk (man-pages)
2020-04-23 16:42 ` Amir Goldstein
2020-05-15 11:44 ` Michael Kerrisk (man-pages)
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).