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From: Al Viro <viro@zeniv.linux.org.uk>
To: Ian Kent <raven@themaw.net>
Cc: Matthew Wilcox <willy@infradead.org>,
	Andreas Dilger <adilger@dilger.ca>,
	Waiman Long <longman@redhat.com>,
	Jonathan Corbet <corbet@lwn.net>,
	Luis Chamberlain <mcgrof@kernel.org>,
	Kees Cook <keescook@chromium.org>,
	Iurii Zaikin <yzaikin@google.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Linux FS Devel <linux-fsdevel@vger.kernel.org>,
	linux-doc@vger.kernel.org,
	Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
	Eric Biggers <ebiggers@google.com>,
	Dave Chinner <david@fromorbit.com>,
	Eric Sandeen <sandeen@redhat.com>
Subject: Re: [PATCH 00/11] fs/dcache: Limit # of negative dentries
Date: Fri, 28 Feb 2020 04:52:55 +0000	[thread overview]
Message-ID: <20200228045255.GJ23230@ZenIV.linux.org.uk> (raw)
In-Reply-To: <5598cd24defe490016479518c7344201f6dfa0eb.camel@themaw.net>

On Fri, Feb 28, 2020 at 12:36:09PM +0800, Ian Kent wrote:

> And let's not forget that file systems are the primary
> source of these and not all create them on lookups.
> I may be mistaken, but I think ext4 does not while xfs
> definitely does.

Both ext4 and xfs bloody well *DO* create hashed negative
dentries on lookups.  There is a pathological case when
they are trying to be case-insensitive (and in that situation
we are SOL - if somebody insists upon mounting with
-o make-it-suck, that's what they bloody well get).

Casefondling idiocy aside, negative lookups are hashed.
On all normal filesystems.  Look for d_splice_alias()
getting passed NULL inode - that's where ->lookup()
instances normally create those.

  reply	other threads:[~2020-02-28  4:53 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-26 16:13 [PATCH 00/11] fs/dcache: Limit # of negative dentries Waiman Long
2020-02-26 16:13 ` [PATCH 01/11] fs/dcache: Fix incorrect accounting " Waiman Long
2020-02-26 16:13 ` [PATCH 02/11] fs/dcache: Simplify __dentry_kill() Waiman Long
2020-02-26 16:13 ` [PATCH 03/11] fs/dcache: Add a counter to track number of children Waiman Long
2020-02-26 16:13 ` [PATCH 04/11] fs/dcache: Add sysctl parameter dentry-dir-max Waiman Long
2020-02-26 16:13 ` [PATCH 05/11] fs/dcache: Reclaim excessive negative dentries in directories Waiman Long
2020-02-26 16:13 ` [PATCH 06/11] fs/dcache: directory opportunistically stores # of positive dentries Waiman Long
2020-02-26 16:14 ` [PATCH 07/11] fs/dcache: Add static key negative_reclaim_enable Waiman Long
2020-02-26 16:14 ` [PATCH 08/11] fs/dcache: Limit dentry reclaim count in negative_reclaim_workfn() Waiman Long
2020-02-26 16:14 ` [PATCH 09/11] fs/dcache: Don't allow small values for dentry-dir-max Waiman Long
2020-02-26 16:14 ` [PATCH 10/11] fs/dcache: Kill off dentry as last resort Waiman Long
2020-02-26 16:14 ` [PATCH 11/11] fs/dcache: Track # of negative dentries reclaimed & killed Waiman Long
2020-02-26 16:29 ` [PATCH 00/11] fs/dcache: Limit # of negative dentries Matthew Wilcox
2020-02-26 19:19   ` Waiman Long
2020-02-26 21:28     ` Matthew Wilcox
2020-02-26 21:28   ` Andreas Dilger
2020-02-26 21:45     ` Matthew Wilcox
2020-02-27  8:07       ` Dave Chinner
2020-02-27  9:55     ` Ian Kent
2020-02-28  3:34       ` Matthew Wilcox
2020-02-28  4:16         ` Ian Kent
2020-02-28  4:36           ` Ian Kent
2020-02-28  4:52             ` Al Viro [this message]
2020-02-28  4:22         ` Al Viro
2020-02-28  4:52           ` Ian Kent
2020-02-28 15:32         ` Waiman Long
2020-02-28 15:39           ` Matthew Wilcox
2020-02-28 19:32         ` Theodore Y. Ts'o
2020-02-27 19:04   ` Eric Sandeen
2020-02-27 22:39     ` Dave Chinner
2020-02-27  8:30 ` Dave Chinner
2020-02-28 15:47   ` Waiman Long
2020-03-15  3:46 ` Matthew Wilcox
2020-03-21 10:17   ` Konstantin Khlebnikov

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