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Commit 47cb498e authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFSv4.1: Clean ups for the device id cache 



The fact that the global device id cache holds a reference to the
nfs4_deviceid_node until it is invisible to rcu lookups implies that
we can always assume that the reference count is non-zero in
_find_get_deviceid.

Also clean up nfs4_put_deviceid_node and the removal of the device id
from the cache.

Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent e885de1a

fs/nfs/pnfs.h

+0 −1
Original line number Diff line number Diff line
@@ -198,7 +198,6 @@ struct nfs4_deviceid_node { 


void nfs4_print_deviceid(const struct nfs4_deviceid *dev_id);

struct nfs4_deviceid_node *nfs4_find_get_deviceid(const struct pnfs_layoutdriver_type *, const struct nfs_client *, const struct nfs4_deviceid *);

struct nfs4_deviceid_node *nfs4_unhash_put_deviceid(const struct pnfs_layoutdriver_type *, const struct nfs_client *, const struct nfs4_deviceid *);

void nfs4_delete_deviceid(const struct pnfs_layoutdriver_type *, const struct nfs_client *, const struct nfs4_deviceid *);

void nfs4_init_deviceid_node(struct nfs4_deviceid_node *,

			     const struct pnfs_layoutdriver_type *,

fs/nfs/pnfs_dev.c

+11 −33
Original line number Diff line number Diff line
@@ -100,8 +100,8 @@ _find_get_deviceid(const struct pnfs_layoutdriver_type *ld, 


	rcu_read_lock();

	d = _lookup_deviceid(ld, clp, id, hash);

	if (d && !atomic_inc_not_zero(&d->ref))

		d = NULL;

	if (d != NULL)

		atomic_inc(&d->ref);

	rcu_read_unlock();

	return d;

}
@@ -115,15 +115,15 @@ nfs4_find_get_deviceid(const struct pnfs_layoutdriver_type *ld, 
EXPORT_SYMBOL_GPL(nfs4_find_get_deviceid);



/*

 * Unhash and put deviceid

 * Remove a deviceid from cache

 *

 * @clp nfs_client associated with deviceid

 * @id the deviceid to unhash

 *

 * @ret the unhashed node, if found and dereferenced to zero, NULL otherwise.

 */

struct nfs4_deviceid_node *

nfs4_unhash_put_deviceid(const struct pnfs_layoutdriver_type *ld,

void

nfs4_delete_deviceid(const struct pnfs_layoutdriver_type *ld,

			 const struct nfs_client *clp, const struct nfs4_deviceid *id)

{

	struct nfs4_deviceid_node *d;
@@ -134,7 +134,7 @@ nfs4_unhash_put_deviceid(const struct pnfs_layoutdriver_type *ld, 
	rcu_read_unlock();

	if (!d) {

		spin_unlock(&nfs4_deviceid_lock);

		return NULL;

		return;

	}

	hlist_del_init_rcu(&d->node);

	spin_unlock(&nfs4_deviceid_lock);
@@ -142,27 +142,6 @@ nfs4_unhash_put_deviceid(const struct pnfs_layoutdriver_type *ld, 


	/* balance the initial ref set in pnfs_insert_deviceid */

	if (atomic_dec_and_test(&d->ref))

		return d;



	return NULL;

}

EXPORT_SYMBOL_GPL(nfs4_unhash_put_deviceid);



/*

 * Delete a deviceid from cache

 *

 * @clp struct nfs_client qualifying the deviceid

 * @id deviceid to delete

 */

void

nfs4_delete_deviceid(const struct pnfs_layoutdriver_type *ld,

		     const struct nfs_client *clp, const struct nfs4_deviceid *id)

{

	struct nfs4_deviceid_node *d;



	d = nfs4_unhash_put_deviceid(ld, clp, id);

	if (!d)

		return;

		d->ld->free_deviceid_node(d);

}

EXPORT_SYMBOL_GPL(nfs4_delete_deviceid);
@@ -221,16 +200,15 @@ EXPORT_SYMBOL_GPL(nfs4_insert_deviceid_node); 
 *

 * @d deviceid node to put

 *

 * @ret true iff the node was deleted

 * return true iff the node was deleted

 * Note that since the test for d->ref == 0 is sufficient to establish

 * that the node is no longer hashed in the global device id cache.

 */

bool

nfs4_put_deviceid_node(struct nfs4_deviceid_node *d)

{

	if (!atomic_dec_and_lock(&d->ref, &nfs4_deviceid_lock))

	if (!atomic_dec_and_test(&d->ref))

		return false;

	hlist_del_init_rcu(&d->node);

	spin_unlock(&nfs4_deviceid_lock);

	synchronize_rcu();

	d->ld->free_deviceid_node(d);

	return true;

}