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From: David Howells <dhowells@redhat.com>
To: NeilBrown <neil@brown.name>, Alexander Viro <viro@zeniv.linux.org.uk>
Cc: dhowells@redhat.com, "Marc Dionne" <marc.dionne@auristor.com>,
	linux-afs@lists.infradead.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 1/2] afs: use d_time instead of d_fsdata
Date: Thu, 02 Jul 2026 11:53:02 +0100	[thread overview]
Message-ID: <147549.1782989582@warthog.procyon.org.uk> (raw)
In-Reply-To: <178298805168.27465.937804342736897811@noble.neil.brown.name>

NeilBrown <neilb@ownmail.net> wrote:

> > > Interestingly the value stored in ->d_time or d_fsdata is u64 which does
> > > not fit in "unsigned long" or "void *" on 32 bit hosts.  Maybe that
> > > doesn't matter.
> > 
> > Hmmm...  It looks like NFS may have a bug here:
> > 
> > static int nfs_dentry_verify_change(struct inode *dir, struct dentry *dentry)
> > {
> > 	if (nfs_server_capable(dir, NFS_CAP_CASE_INSENSITIVE) &&
> > 	    d_really_is_negative(dentry))
> > 		return dentry->d_time == inode_peek_iversion_raw(dir);
> > 	return nfs_verify_change_attribute(dir, dentry->d_time);
> > }
> > 
> > dentry->d_time may be 32-bits, but inode_peek_iversion_raw() is always 64 bits
> > and i_version is set to the 64-bit fattr->change_attr.
> 
> I wonder if there would be any appetite for making d_time (or d_version)
> always 64bit, much like i_ino was recently changed to u64.

I suspect Al wouldn't be happy about that.  He counts the bits in struct
dentry very carefully.

David


  reply	other threads:[~2026-07-02 10:53 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-07-02  1:58 [PATCH 0/2] afs: avoid unhash/rehash NeilBrown
2026-07-02  1:58 ` [PATCH 1/2] afs: use d_time instead of d_fsdata NeilBrown
2026-07-02  8:54   ` David Howells
2026-07-02 10:12     ` NeilBrown
2026-07-02  9:09   ` David Howells
2026-07-02 10:27     ` NeilBrown
2026-07-02 10:53       ` David Howells [this message]
2026-07-02  1:58 ` [PATCH 2/2] afs: don't unhash/rehash dentries during unlink/rename NeilBrown

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