linux-ext4 - Re: [PATCH v6 04/21] fsnotify: Reserve mark flag bits for backends

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Message-ID: <87k0kc2poz.fsf@collabora.com>
Date:   Mon, 23 Aug 2021 10:36:28 -0400
From:   Gabriel Krisman Bertazi <krisman@...labora.com>
To:     Jan Kara <jack@...e.cz>
Cc:     Amir Goldstein <amir73il@...il.com>, Jan Kara <jack@...e.com>,
        Linux API <linux-api@...r.kernel.org>,
        Ext4 <linux-ext4@...r.kernel.org>,
        linux-fsdevel <linux-fsdevel@...r.kernel.org>,
        Khazhismel Kumykov <khazhy@...gle.com>,
        David Howells <dhowells@...hat.com>,
        Dave Chinner <david@...morbit.com>,
        Theodore Tso <tytso@....edu>,
        "Darrick J. Wong" <djwong@...nel.org>,
        Matthew Bobrowski <repnop@...gle.com>, kernel@...labora.com
Subject: Re: [PATCH v6 04/21] fsnotify: Reserve mark flag bits for backends

Jan Kara <jack@...e.cz> writes:

> On Fri 13-08-21 10:28:27, Amir Goldstein wrote:
>> On Fri, Aug 13, 2021 at 12:40 AM Gabriel Krisman Bertazi
>> <krisman@...labora.com> wrote:
>> >
>> > Split out the final bits of struct fsnotify_mark->flags for use by a
>> > backend.
>> >
>> > Signed-off-by: Gabriel Krisman Bertazi <krisman@...labora.com>
>> >
>> > Changes since v1:
>> >   - turn consts into defines (jan)
>> > ---
>> >  include/linux/fsnotify_backend.h | 18 +++++++++++++++---
>> >  1 file changed, 15 insertions(+), 3 deletions(-)
>> >
>> > diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
>> > index 1ce66748a2d2..ae1bd9f06808 100644
>> > --- a/include/linux/fsnotify_backend.h
>> > +++ b/include/linux/fsnotify_backend.h
>> > @@ -363,6 +363,20 @@ struct fsnotify_mark_connector {
>> >         struct hlist_head list;
>> >  };
>> >
>> > +enum fsnotify_mark_bits {
>> > +       FSN_MARK_FL_BIT_IGNORED_SURV_MODIFY,
>> > +       FSN_MARK_FL_BIT_ALIVE,
>> > +       FSN_MARK_FL_BIT_ATTACHED,
>> > +       FSN_MARK_PRIVATE_FLAGS,
>> > +};
>> > +
>> > +#define FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY \
>> > +       (1 << FSN_MARK_FL_BIT_IGNORED_SURV_MODIFY)
>> > +#define FSNOTIFY_MARK_FLAG_ALIVE \
>> > +       (1 << FSN_MARK_FL_BIT_ALIVE)
>> > +#define FSNOTIFY_MARK_FLAG_ATTACHED \
>> > +       (1 << FSN_MARK_FL_BIT_ATTACHED)
>> > +
>> >  /*
>> >   * A mark is simply an object attached to an in core inode which allows an
>> >   * fsnotify listener to indicate they are either no longer interested in events
>> > @@ -398,9 +412,7 @@ struct fsnotify_mark {
>> >         struct fsnotify_mark_connector *connector;
>> >         /* Events types to ignore [mark->lock, group->mark_mutex] */
>> >         __u32 ignored_mask;
>> > -#define FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY 0x01
>> > -#define FSNOTIFY_MARK_FLAG_ALIVE               0x02
>> > -#define FSNOTIFY_MARK_FLAG_ATTACHED            0x04
>> > +       /* Upper bits [31:PRIVATE_FLAGS] are reserved for backend usage */
>> 
>> I don't understand what [31:PRIVATE_FLAGS] means
>
> I think it should be [FSN_MARK_PRIVATE_FLAGS:31] (identifying a range of
> bits). I'd maybe write just "Bits starting from FSN_MARK_PRIVATE_FLAGS are
> reserved for backend usage". With this fixed feel free to add:

Thank you, I will address the comment and add your reviewed-by tags.

-- 
Gabriel Krisman Bertazi