All of lore.kernel.org
 help / color / mirror / Atom feed
From: Ian Kent <raven@themaw.net>
To: Amir Goldstein <amir73il@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Tejun Heo <tj@kernel.org>, Minchan Kim <minchan@kernel.org>,
	Eric Sandeen <sandeen@sandeen.net>,
	Al Viro <viro@zeniv.linux.org.uk>,
	Rick Lindsley <ricklind@linux.vnet.ibm.com>,
	David Howells <dhowells@redhat.com>,
	Miklos Szeredi <miklos@szeredi.hu>,
	Carlos Maiolino <cmaiolino@redhat.com>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/2] kernfs: dont take i_lock on revalidate
Date: Tue, 1 Nov 2022 16:09:25 +0800	[thread overview]
Message-ID: <5fd7f78e-4b8f-1dd4-5b3c-e2c3583b9e9d@themaw.net> (raw)
In-Reply-To: <CAOQ4uxjiEbHwT7M1GhPb_GFn-oiuvqwS1aOw7N9N8cu5jam5Yw@mail.gmail.com>


On 1/11/22 15:46, Amir Goldstein wrote:
> On Tue, Oct 18, 2022 at 5:58 AM Ian Kent <raven@themaw.net> wrote:
>> In kernfs_dop_revalidate() when the passed in dentry is negative the
>> dentry directory is checked to see if it has changed and if so the
>> negative dentry is discarded so it can refreshed. During this check
>> the dentry inode i_lock is taken to mitigate against a possible
>> concurrent rename.
>>
>> But if it's racing with a rename, becuase the dentry is negative, it
>> can't be the source it must be the target and it must be going to do
>> a d_move() otherwise the rename will return an error.
>>
>> In this case the parent dentry of the target will not change, it will
>> be the same over the d_move(), only the source dentry parent may change
>> so the inode i_lock isn't needed.
> You meant d_lock.
> Same for the commit title.

Ha, well how do you like that, such an obvious mistake, how

did I not see it?


Not sure what to do about it now though ...

Any suggestions anyone?


Ian



      reply	other threads:[~2022-11-01  8:09 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-18  2:32 [PATCH 0/2] kernfs: remove i_lock usage that isn't needed Ian Kent
2022-10-18  2:32 ` [PATCH 1/2] kernfs: dont take i_lock on inode attr read Ian Kent
2022-10-24  8:50   ` Miklos Szeredi
2022-10-31 22:30   ` Tejun Heo
2022-12-21 13:34     ` Anders Roxell
2022-12-22 23:11       ` Ian Kent
2022-12-29  9:20         ` Arnd Bergmann
2022-12-29 13:07           ` Ian Kent
2023-01-23  3:11             ` Ian Kent
2023-07-18 19:00               ` Anders Roxell
2023-07-19  4:23                 ` Ian Kent
2023-07-20  2:03                   ` Ian Kent
2023-07-26 13:49                     ` Miklos Szeredi
2023-07-27  0:38                     ` Ian Kent
2023-07-27  4:30                       ` Imran Khan
2023-07-27  5:35                         ` Imran Khan
2023-07-28  0:00                         ` Ian Kent
2023-07-28  0:16                           ` Ian Kent
2023-07-28  1:06                             ` Imran Khan
2023-07-28  1:29                               ` Ian Kent
2022-10-18  2:32 ` [PATCH 2/2] kernfs: dont take i_lock on revalidate Ian Kent
2022-10-24  8:38   ` Miklos Szeredi
2022-10-31 22:31   ` Tejun Heo
2022-11-01  7:46   ` Amir Goldstein
2022-11-01  8:09     ` Ian Kent [this message]

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=5fd7f78e-4b8f-1dd4-5b3c-e2c3583b9e9d@themaw.net \
    --to=raven@themaw.net \
    --cc=amir73il@gmail.com \
    --cc=cmaiolino@redhat.com \
    --cc=dhowells@redhat.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=miklos@szeredi.hu \
    --cc=minchan@kernel.org \
    --cc=ricklind@linux.vnet.ibm.com \
    --cc=sandeen@sandeen.net \
    --cc=tj@kernel.org \
    --cc=viro@zeniv.linux.org.uk \
    /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
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.