From: Theodore Tso <tytso@mit.edu>
To: Jan Kara <jack@suse.cz>
Cc: Jan Blunck <jblunck@suse.de>, Christoph Hellwig <hch@lst.de>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Linux-Kernel Mailinglist <linux-kernel@vger.kernel.org>,
linux-fsdevel@vger.kernel.org
Subject: Re: [RFC 0/2] readdir() as an inode operation
Date: Wed, 31 Oct 2007 03:13:53 -0400 [thread overview]
Message-ID: <20071031071353.GB20965@thunk.org> (raw)
In-Reply-To: <20071030152604.GC27039@atrey.karlin.mff.cuni.cz>
On Tue, Oct 30, 2007 at 04:26:04PM +0100, Jan Kara wrote:
> > This is a first try to move readdir() to become an inode operation. This is
> > necessary for a VFS implementation of "something like union-mounts" where a
> > readdir() needs to read the directory contents of multiple directories.
> > Besides that the new interface is no longer giving the struct file to the
> > filesystem implementations anymore.
> >
> > Comments, please?
> Hmm, are you sure there are no users which keep some per-struct-file
> information for directories? File offset is one such obvious thing which
> you've handled but actually filesystem with more complicated structure
> of directory may remember some hints about where we really are, keep
> some readahead information or so...
For example, the ext3 filesystem, when it is supported hash tree, does
exactly this. See ext3_htree_store_dirent() in fs/ext3/dir.c and
ext3_htree_fill_tree() in fs/ext3/namei.c.
So your patch would break ext3 htree support.
- Ted
prev parent reply other threads:[~2007-10-31 7:16 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-20 10:09 [RFC 0/2] readdir() as an inode operation Jan Blunck
2007-10-20 10:09 ` [RFC 1/2] i_op->readdir: Change readdir() to be " Jan Blunck
2007-10-20 10:09 ` [RFC 2/2] i_op->readdir: Change libfs users to the new interface Jan Blunck
2007-10-30 15:26 ` [RFC 0/2] readdir() as an inode operation Jan Kara
2007-10-31 3:43 ` Brad Boyer
2007-10-31 7:13 ` Theodore Tso [this message]
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