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From: Jan Kara <jack@suse.cz>
To: Amir Goldstein <amir73il@gmail.com>
Cc: Jan Kara <jack@suse.cz>, linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: [PATCH v5 16/22] fsnotify: remove check that source dentry is positive
Date: Thu, 16 Jul 2020 16:06:18 +0200	[thread overview]
Message-ID: <20200716140618.GF5022@quack2.suse.cz> (raw)
In-Reply-To: <CAOQ4uxjXQWRtxWbiL8Y_01dMC8ntbYi4QnzpfHQqiJ3pP=i5Vg@mail.gmail.com>

On Thu 16-07-20 16:54:08, Amir Goldstein wrote:
> On Thu, Jul 16, 2020 at 4:29 PM Jan Kara <jack@suse.cz> wrote:
> >
> > On Thu 16-07-20 15:13:11, Jan Kara wrote:
> > > On Thu 16-07-20 11:42:24, Amir Goldstein wrote:
> > > > Remove the unneeded check for positive source dentry in
> > > > fsnotify_move().
> > > >
> > > > fsnotify_move() hook is mostly called from vfs_rename() under
> > > > lock_rename() and vfs_rename() starts with may_delete() test that
> > > > verifies positive source dentry.  The only other caller of
> > > > fsnotify_move() - debugfs_rename() also verifies positive source.
> > > >
> > > > Signed-off-by: Amir Goldstein <amir73il@gmail.com>
> > >
> > > But in vfs_rename() if RENAME_EXCHANGE is set and target is NULL,
> > > new_dentry can be negative when calling fsnotify_move() AFAICT, cannot it?
> >
> > FWIW, renameat2() doesn't allow RENAME_EXCHANGE with non-existent target
> > and I didn't find any other place that could call vfs_rename() with
> > RENAME_EXCHANGE and negative target but still vfs_rename() seems to support
> > that and so fsnotify should likely handle that as well.
> 
> If some code did call vfs_rename() like that d_exchange() will barf:
> 
> void d_exchange(struct dentry *dentry1, struct dentry *dentry2)
> {
>         write_seqlock(&rename_lock);
> 
>         WARN_ON(!dentry1->d_inode);
>         WARN_ON(!dentry2->d_inode);

Good point. Thanks for explanation!

								Honza
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

  reply	other threads:[~2020-07-16 14:06 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
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 [this message]
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

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