* 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)
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