From: Al Viro <viro@zeniv.linux.org.uk>
To: NeilBrown <neil@brown.name>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Christian Brauner <brauner@kernel.org>, Jan Kara <jack@suse.cz>,
Jeff Layton <jlayton@kernel.org>,
Trond Myklebust <trondmy@kernel.org>,
Anna Schumaker <anna@kernel.org>,
Miklos Szeredi <miklos@szeredi.hu>,
Amir Goldstein <amir73il@gmail.com>, Jeremy Kerr <jk@ozlabs.org>,
Ard Biesheuvel <ardb@kernel.org>,
linux-efi@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-nfs@vger.kernel.org, linux-unionfs@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 05/19] VFS: introduce d_alloc_noblock()
Date: Tue, 28 Apr 2026 03:22:45 +0100 [thread overview]
Message-ID: <20260428022245.GU3518998@ZenIV> (raw)
In-Reply-To: <20260427040517.828226-6-neilb@ownmail.net>
On Mon, Apr 27, 2026 at 02:01:23PM +1000, NeilBrown wrote:
> From: NeilBrown <neil@brown.name>
>
> Several filesystems use the results of readdir to prime the dcache.
> These filesystems use d_alloc_parallel() which can block if there is a
> concurrent lookup. Blocking in that case is pointless as the lookup
> will add info to the dcache and there is no value in the readdir waiting
> to see if it should add the info too.
... except that there is - large part of the reasons for that in the original
user (procfs) is that we want getdents() + open() + fstat() + compare ->st_ino
from fstat() with ->d_ino from getdents() to work, even if you race with lookup
from another process coming in the middle of your getdents().
What are your plans in that area?
next prev parent reply other threads:[~2026-04-28 2:22 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-27 4:01 [PATCH v3 00/19] Prepare to lift lookup out of exclusive lock for directory ops NeilBrown
2026-04-27 4:01 ` [PATCH v3 01/19] VFS: fix various typos in documentation for start_creating start_removing etc NeilBrown
2026-04-27 4:01 ` [PATCH v3 02/19] VFS: enhance d_splice_alias() to handle in-lookup dentries NeilBrown
2026-04-27 4:01 ` [PATCH v3 03/19] VFS: allow d_alloc_name() to be used with ->d_hash NeilBrown
2026-04-28 2:10 ` Al Viro
2026-04-27 4:01 ` [PATCH v3 04/19] VFS: use wait_var_event for waiting in d_alloc_parallel() NeilBrown
2026-04-28 3:37 ` Al Viro
2026-04-27 4:01 ` [PATCH v3 05/19] VFS: introduce d_alloc_noblock() NeilBrown
2026-04-28 2:22 ` Al Viro [this message]
2026-04-27 4:01 ` [PATCH v3 06/19] VFS: add d_duplicate() NeilBrown
2026-04-27 4:01 ` [PATCH v3 07/19] VFS: Add LOOKUP_SHARED flag NeilBrown
2026-04-27 7:43 ` Amir Goldstein
2026-04-27 8:47 ` NeilBrown
2026-04-27 9:05 ` Amir Goldstein
2026-04-27 23:51 ` NeilBrown
2026-04-27 4:01 ` [PATCH v3 08/19] VFS/xfs/ntfs: drop parent lock across d_alloc_parallel() in d_add_ci() NeilBrown
2026-04-27 7:49 ` Amir Goldstein
2026-04-27 8:48 ` NeilBrown
2026-04-27 4:01 ` [PATCH v3 09/19] ovl: stop using lookup_one() in iterate_shared() handling NeilBrown
2026-04-27 10:10 ` Amir Goldstein
2026-04-28 0:24 ` NeilBrown
2026-04-27 4:01 ` [PATCH v3 10/19] VFS/ovl: add d_alloc_noblock_return() NeilBrown
2026-04-27 9:40 ` Amir Goldstein
2026-04-28 0:34 ` NeilBrown
2026-04-28 4:35 ` Al Viro
2026-04-27 4:01 ` [PATCH v3 11/19] efivarfs: use d_alloc_name() NeilBrown
2026-04-27 4:01 ` [PATCH v3 12/19] shmem: use d_duplicate() NeilBrown
2026-04-27 4:01 ` [PATCH v3 13/19] nfs: remove d_drop()/d_alloc_parallel() from nfs_atomic_open() NeilBrown
2026-04-27 4:01 ` [PATCH v3 14/19] nfs: use d_splice_alias() in nfs_link() NeilBrown
2026-04-27 4:01 ` [PATCH v3 15/19] nfs: don't d_drop() before d_splice_alias() NeilBrown
2026-04-27 4:01 ` [PATCH v3 16/19] nfs: don't d_drop() before d_splice_alias() in atomic_create NeilBrown
2026-04-27 4:01 ` [PATCH v3 17/19] nfs: Use d_alloc_noblock() in nfs_prime_dcache() NeilBrown
2026-04-27 4:01 ` [PATCH v3 18/19] nfs: use d_alloc_noblock() in silly-rename NeilBrown
2026-04-27 4:01 ` [PATCH v3 19/19] nfs: use d_duplicate() NeilBrown
2026-04-27 8:42 ` [syzbot ci] Re: Prepare to lift lookup out of exclusive lock for directory ops syzbot ci
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