linux-kernel - Re: [RFC PATCH v6 0/4] fuse: work queues to invalided dentries

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Message-ID: <877bwp4sr6.fsf@igalia.com>
Date: Mon, 20 Oct 2025 14:17:33 +0100
From: Luis Henriques <luis@...lia.com>
To: Miklos Szeredi <miklos@...redi.hu>
Cc: Bernd Schubert <bernd@...ernd.com>,  Laura Promberger
 <laura.promberger@...n.ch>,  Dave Chinner <david@...morbit.com>,  Matt
 Harvey <mharvey@...ptrading.com>,  linux-fsdevel@...r.kernel.org,
  kernel-dev@...lia.com,  linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH v6 0/4] fuse: work queues to invalided dentries

Hey Miklos,

On Tue, Sep 16 2025, Luis Henriques wrote:

> Hi Miklos,
>
> Here's a new version of the patchset to invalidate expired dentries.  Most
> of the changes (and there are a lot of them!) result from the v5 review.
> See below for details.

Just a gentle ping to make sure it doesn't fall through the cracks.

Cheers,
-- 
Luís


> Changes since v5:
>
> - Changes to dcache: export shrink_dentry_list() and add new helper
>   d_dispose_if_unused()
> - Reduced hash lock array size
> - Set 'inval_wq' max value to USHRT_MAX to prevent a potential overflow in
>   secs_to_jiffies()
> - Updated 'inval_wq' parameter description and comment
> - Removed useless check in fuse_dentry_tree_del_node()
> - Make fuse_dentry_tree_work() use dcache helpers d_dispose_if_unused() and
>   shrink_dentry_list()
> - Fix usage of need_resched() (replaced with cond_resched())
> - fuse_dentry_tree_cleanup() now simply does a WARN_ON() if there are
>   non-empty trees
> - Removed TODO comment in fuse_conn_destroy() -- no need to prune trees
> - Have fuse_epoch_work() use of shrink_dcache_sb() instead of going through
>   all the trees
> - Refactor fuse_conn_put() in a separate patch
> - Fix bug in fuse_dentry_tree_add_node() for cases where dentries have the
>   same timeout
> - Reword some of the commits text
>
> Changes since v4:
>  
> - Dropped extra check in fuse_dentry_tree_add_node() (Chunsheng)
> - Make the dentries trees global instead of per fuse_conn (Miklos)
> - Protect trees with hashed locking instead of a single lock (Miklos)
> - Added new work queue (2nd patch) specifically to handle epoch (Miklos)
>  
> Changes since v3:
>  
> - Use of need_resched() instead of limiting the work queue to run for 5
>   seconds
> - Restore usage of union with rcu_head, in struct fuse_dentry
> - Minor changes in comments (e.g. s/workqueue/work queue/)
>  
> Changes since v2:
>  
> - Major rework, the dentries tree nodes are now in fuse_dentry and they are
>   tied to the actual dentry lifetime
> - Mount option is now a module parameter
> - workqueue now runs for at most 5 seconds before rescheduling
>
> Luis Henriques (4):
>   dcache: export shrink_dentry_list() and new helper
>     d_dispose_if_unused()
>   fuse: new work queue to periodically invalidate expired dentries
>   fuse: new work queue to invalidate dentries from old epochs
>   fuse: refactor fuse_conn_put() to remove negative logic.
>
>  fs/dcache.c            |  18 ++--
>  fs/fuse/dev.c          |   7 +-
>  fs/fuse/dir.c          | 237 +++++++++++++++++++++++++++++++++++++----
>  fs/fuse/fuse_i.h       |  14 +++
>  fs/fuse/inode.c        |  44 ++++----
>  include/linux/dcache.h |   2 +
>  6 files changed, 273 insertions(+), 49 deletions(-)
>