linux-kernel - Re: [PATCH 0/2] fs/dcache: fix cache inconsistency on case-insensitive lookups

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Message-ID: <181856a3-3378-4136-9734-b20a732d10c4@collabora.com>
Date: Thu, 15 Aug 2024 09:02:58 +0300
From: Eugen Hristev <eugen.hristev@...labora.com>
To: viro@...iv.linux.org.uk, brauner@...nel.org, tytso@....edu,
 linux-ext4@...r.kernel.org
Cc: jack@...e.cz, adilger.kernel@...ger.ca, linux-fsdevel@...r.kernel.org,
 linux-kernel@...r.kernel.org, krisman@...e.de, kernel@...labora.com,
 shreeya.patel@...labora.com
Subject: Re: [PATCH 0/2] fs/dcache: fix cache inconsistency on
 case-insensitive lookups

On 7/5/24 09:26, Eugen Hristev wrote:
> Hello,
> 
> This is an attempt to go back to this old patch series here :
> 
> https://lore.kernel.org/lkml/cover.1632909358.git.shreeya.patel@collabora.com/
> 
> First patch fixes a possible hang when d_add_ci is called from a filesystem's
> lookup function (like xfs is doing)
> d_alloc_parallel -> lookup -> d_add_ci -> d_alloc_parallel
> 
> Second patch solves the issue of having the dcache saving the entry with
> the same case as it's being looked up instead of saving the real file name
> from the storage.
> Please check above thread for motivation on why this should be changed.
> 
> Some further old discussions here as well:
> https://patchwork.ozlabs.org/project/linux-ext4/patch/20180924215655.3676-20-krisman@collabora.co.uk/
> 
> I am not sure whether this is the right way to fix this, but I think
> I have considered all cases discussed in previous threads.
> 
> Thank you for your review and consideration,
> Eugen
> 

Hello,

I have sent this series a while back, anyone has any opinion on whether it's a good
way to solve the problem ?

Thank you,
Eugen

> 
> Eugen Hristev (2):
>   fs/dcache: introduce d_alloc_parallel_check_existing
>   ext4: in lookup call d_add_ci if there is a case mismatch
> 
>  fs/dcache.c            | 29 +++++++++++++++++++++++------
>  fs/ext4/namei.c        | 13 +++++++++++++
>  include/linux/dcache.h |  4 ++++
>  3 files changed, 40 insertions(+), 6 deletions(-)
>