linux-fsdevel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Amir Goldstein <amir73il@gmail.com>
To: Jan Kara <jack@suse.cz>
Cc: linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: [PATCH v5 10/22] fanotify: no external fh buffer in fanotify_name_event
Date: Thu, 16 Jul 2020 16:30:42 +0300	[thread overview]
Message-ID: <CAOQ4uxhAO-bwHwh4vK__omwHCcLsD6JmFWCHz6t7VeiqpXDSqA@mail.gmail.com> (raw)
In-Reply-To: <20200716124412.GA5022@quack2.suse.cz>

On Thu, Jul 16, 2020 at 3:44 PM Jan Kara <jack@suse.cz> wrote:
>
> On Thu 16-07-20 11:42:18, Amir Goldstein wrote:
> > The fanotify_fh struct has an inline buffer of size 12 which is enough
> > to store the most common local filesystem file handles (e.g. ext4, xfs).
> > For file handles that do not fit in the inline buffer (e.g. btrfs), an
> > external buffer is allocated to store the file handle.
> >
> > When allocating a variable size fanotify_name_event, there is no point
> > in allocating also an external fh buffer when file handle does not fit
> > in the inline buffer.
> >
> > Check required size for encoding fh, preallocate an event buffer
> > sufficient to contain both file handle and name and store the name after
> > the file handle.
> >
> > At this time, when not reporting name in event, we still allocate
> > the fixed size fanotify_fid_event and an external buffer for large
> > file handles, but fanotify_alloc_name_event() has already been prepared
> > to accept a NULL file_name.
> >
> > Signed-off-by: Amir Goldstein <amir73il@gmail.com>
>
> When reading this, I've got one cleanup idea for later: For FID events, we
> could now easily check fh len in fanotify_alloc_fid_event(). If it fits in
> inline size, allocate the event from kmem cache, if it does not, allocate
> appropriately sized event from kmalloc(). Similarly when freeing event we
> could check fh len to determine how to free the event. This way we can
> completely get rid of the external buffer code, somewhat simplify all
> the fh handling, remove the alignment restrictions on fanotify_fh and
> fanotify_info...
>

OK. Note that the f_handle buffer passed to filesystems is expected to be
aligned anyway, although for encoding it may be less important, see:

cbe7fba8edfc ("ovl: make sure that real fid is 32bit aligned in memory")

Thanks,
Amir.

  reply	other threads:[~2020-07-16 13:30 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-16  8:42 [PATCH v5 00/22] fanotify events with name info Amir Goldstein
2020-07-16  8:42 ` [PATCH v5 01/22] fanotify: generalize the handling of extra event flags Amir Goldstein
2020-07-16  8:42 ` [PATCH v5 02/22] fanotify: generalize merge logic of events on dir Amir Goldstein
2020-07-16  8:42 ` [PATCH v5 03/22] fanotify: distinguish between fid encode error and null fid Amir Goldstein
2020-07-16  8:42 ` [PATCH v5 04/22] fanotify: generalize test for FAN_REPORT_FID Amir Goldstein
2020-07-16  8:42 ` [PATCH v5 05/22] fanotify: mask out special event flags from ignored mask Amir Goldstein
2020-07-16  8:42 ` [PATCH v5 06/22] fanotify: prepare for implicit event flags in mark mask Amir Goldstein
2020-07-16  8:42 ` [PATCH v5 07/22] fanotify: use FAN_EVENT_ON_CHILD as implicit flag on sb/mount/non-dir marks Amir Goldstein
2020-07-16  8:42 ` [PATCH v5 08/22] fsnotify: add object type "child" to object type iterator Amir Goldstein
2020-07-16  8:42 ` [PATCH v5 09/22] fanotify: use struct fanotify_info to parcel the variable size buffer Amir Goldstein
2020-07-16  8:42 ` [PATCH v5 10/22] fanotify: no external fh buffer in fanotify_name_event Amir Goldstein
2020-07-16 12:44   ` Jan Kara
2020-07-16 13:30     ` Amir Goldstein [this message]
2020-07-16  8:42 ` [PATCH v5 11/22] dnotify: report both events on parent and child with single callback Amir Goldstein
2020-07-16  8:42 ` [PATCH v5 12/22] inotify: " Amir Goldstein
2020-07-16 12:52   ` Jan Kara
2020-07-16 14:25     ` Amir Goldstein
2020-07-16 15:17       ` Jan Kara
2020-07-16  8:42 ` [PATCH v5 13/22] fanotify: " Amir Goldstein
2020-07-16  8:42 ` [PATCH v5 14/22] fsnotify: send event to " Amir Goldstein
2020-07-16  8:42 ` [PATCH v5 15/22] fsnotify: send event with parent/name info to sb/mount/non-dir marks Amir Goldstein
2020-07-16 17:01   ` Jan Kara
2020-07-16 17:20     ` Amir Goldstein
2020-07-16 17:57       ` Jan Kara
2020-07-16 18:42         ` Amir Goldstein
2020-07-16 22:34           ` Jan Kara
2020-07-17  3:49             ` Amir Goldstein
2020-07-16  8:42 ` [PATCH v5 16/22] fsnotify: remove check that source dentry is positive Amir Goldstein
2020-07-16 13:13   ` Jan Kara
2020-07-16 13:29     ` Jan Kara
2020-07-16 13:54       ` Amir Goldstein
2020-07-16 14:06         ` Jan Kara
2020-07-16  8:42 ` [PATCH v5 17/22] fsnotify: send MOVE_SELF event with parent/name info Amir Goldstein
2020-07-16 13:45   ` Jan Kara
2020-07-16 13:59     ` Amir Goldstein
2020-07-16 14:10       ` Amir Goldstein
2020-07-16 15:57         ` Amir Goldstein
2020-07-16  8:42 ` [PATCH v5 18/22] fanotify: add basic support for FAN_REPORT_DIR_FID Amir Goldstein
2020-07-16  8:42 ` [PATCH v5 19/22] fanotify: report events with parent dir fid to sb/mount/non-dir marks Amir Goldstein
2020-07-16  8:42 ` [PATCH v5 20/22] fanotify: add support for FAN_REPORT_NAME Amir Goldstein
2020-07-16  8:42 ` [PATCH v5 21/22] fanotify: report parent fid + name + child fid Amir Goldstein
2020-07-16 15:59   ` Jan Kara
2020-07-16 16:08     ` Amir Goldstein
2020-07-16  8:42 ` [PATCH v5 22/22] fanotify: report parent fid " Amir Goldstein
2020-07-16 17:13 ` [PATCH v5 00/22] fanotify events with name info Jan Kara

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=CAOQ4uxhAO-bwHwh4vK__omwHCcLsD6JmFWCHz6t7VeiqpXDSqA@mail.gmail.com \
    --to=amir73il@gmail.com \
    --cc=jack@suse.cz \
    --cc=linux-fsdevel@vger.kernel.org \
    --subject='Re: [PATCH v5 10/22] fanotify: no external fh buffer in fanotify_name_event' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

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).