Commit d826e036 authored by Ian Kent's avatar Ian Kent Committed by Greg Kroah-Hartman
Browse files

kernfs: move revalidate to be near lookup 



While the dentry operation kernfs_dop_revalidate() is grouped with
dentry type functions it also has a strong affinity to the inode
operation ->lookup().

It makes sense to locate this function near to kernfs_iop_lookup()
because we will be adding VFS negative dentry caching to reduce path
lookup overhead for non-existent paths.

There's no functional change from this patch.

Signed-off-by: default avatarIan Kent <raven@themaw.net>
Reviewed-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
Link: https://lore.kernel.org/r/162375275365.232295.8995526416263659926.stgit@web.messagingengine.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 68afbd84

fs/kernfs/dir.c

+43 −43
Original line number Diff line number Diff line
@@ -548,49 +548,6 @@ void kernfs_put(struct kernfs_node *kn) 
}

EXPORT_SYMBOL_GPL(kernfs_put);



static int kernfs_dop_revalidate(struct dentry *dentry, unsigned int flags)

{

	struct kernfs_node *kn;



	if (flags & LOOKUP_RCU)

		return -ECHILD;



	/* Always perform fresh lookup for negatives */

	if (d_really_is_negative(dentry))

		goto out_bad_unlocked;



	kn = kernfs_dentry_node(dentry);

	mutex_lock(&kernfs_mutex);



	/* The kernfs node has been deactivated */

	if (!kernfs_active(kn))

		goto out_bad;



	/* The kernfs node has been moved? */

	if (kernfs_dentry_node(dentry->d_parent) != kn->parent)

		goto out_bad;



	/* The kernfs node has been renamed */

	if (strcmp(dentry->d_name.name, kn->name) != 0)

		goto out_bad;



	/* The kernfs node has been moved to a different namespace */

	if (kn->parent && kernfs_ns_enabled(kn->parent) &&

	    kernfs_info(dentry->d_sb)->ns != kn->ns)

		goto out_bad;



	mutex_unlock(&kernfs_mutex);

	return 1;

out_bad:

	mutex_unlock(&kernfs_mutex);

out_bad_unlocked:

	return 0;

}



const struct dentry_operations kernfs_dops = {

	.d_revalidate	= kernfs_dop_revalidate,

};



/**

 * kernfs_node_from_dentry - determine kernfs_node associated with a dentry

 * @dentry: the dentry in question
@@ -1073,6 +1030,49 @@ struct kernfs_node *kernfs_create_empty_dir(struct kernfs_node *parent, 
	return ERR_PTR(rc);

}



static int kernfs_dop_revalidate(struct dentry *dentry, unsigned int flags)

{

	struct kernfs_node *kn;



	if (flags & LOOKUP_RCU)

		return -ECHILD;



	/* Always perform fresh lookup for negatives */

	if (d_really_is_negative(dentry))

		goto out_bad_unlocked;



	kn = kernfs_dentry_node(dentry);

	mutex_lock(&kernfs_mutex);



	/* The kernfs node has been deactivated */

	if (!kernfs_active(kn))

		goto out_bad;



	/* The kernfs node has been moved? */

	if (kernfs_dentry_node(dentry->d_parent) != kn->parent)

		goto out_bad;



	/* The kernfs node has been renamed */

	if (strcmp(dentry->d_name.name, kn->name) != 0)

		goto out_bad;



	/* The kernfs node has been moved to a different namespace */

	if (kn->parent && kernfs_ns_enabled(kn->parent) &&

	    kernfs_info(dentry->d_sb)->ns != kn->ns)

		goto out_bad;



	mutex_unlock(&kernfs_mutex);

	return 1;

out_bad:

	mutex_unlock(&kernfs_mutex);

out_bad_unlocked:

	return 0;

}



const struct dentry_operations kernfs_dops = {

	.d_revalidate	= kernfs_dop_revalidate,

};



static struct dentry *kernfs_iop_lookup(struct inode *dir,

					struct dentry *dentry,

					unsigned int flags)