Commit 21fd9e87 authored by Chengen Du's avatar Chengen Du Committed by Anna Schumaker
Browse files

NFS: Correct timing for assigning access cache timestamp 



When the user's login time is newer than the cache's timestamp,
the original entry in the RB-tree will be replaced by a new entry.
Currently, the timestamp is only set if the entry is not found in
the RB-tree, which can cause the timestamp to be undefined when
the entry exists. This may result in a significant increase in
ACCESS operations if the timestamp is set to zero.

Signed-off-by: default avatarChengen Du <chengen.du@canonical.com>
Fixes: 0eb43812 ("NFS: Clear the file access cache upon login”)
Reviewed-by: default avatarBenjamin Coddington <bcodding@redhat.com>
Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
parent 7ff84910

fs/nfs/dir.c

+1 −1
Original line number Diff line number Diff line
@@ -3089,7 +3089,6 @@ static void nfs_access_add_rbtree(struct inode *inode, 
		else

			goto found;

	}

	set->timestamp = ktime_get_ns();

	rb_link_node(&set->rb_node, parent, p);

	rb_insert_color(&set->rb_node, root_node);

	list_add_tail(&set->lru, &nfsi->access_cache_entry_lru);
@@ -3114,6 +3113,7 @@ void nfs_access_add_cache(struct inode *inode, struct nfs_access_entry *set, 
	cache->fsgid = cred->fsgid;

	cache->group_info = get_group_info(cred->group_info);

	cache->mask = set->mask;

	cache->timestamp = ktime_get_ns();



	/* The above field assignments must be visible

	 * before this item appears on the lru.  We cannot easily