From 1c3c07e9f6cc50dab2aeb8051325e317d4f6c70e Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Tue, 25 Jul 2006 11:28:18 -0400 Subject: NFS: Add a new ACCESS rpc call cache to the linux nfs client The current access cache only allows one entry at a time to be cached for each inode. Add a per-inode red-black tree in order to allow more than one to be cached at a time. Should significantly cut down the time spent in path traversal for shared directories such as ${PATH}, /usr/share, etc. Signed-off-by: Trond Myklebust --- fs/nfs/dir.c | 133 +++++++++++++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 116 insertions(+), 17 deletions(-) (limited to 'fs/nfs/dir.c') diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index e7ffb4deb3e..094afded2b1 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -1638,35 +1638,134 @@ out: return error; } -int nfs_access_get_cached(struct inode *inode, struct rpc_cred *cred, struct nfs_access_entry *res) +static void nfs_access_free_entry(struct nfs_access_entry *entry) +{ + put_rpccred(entry->cred); + kfree(entry); +} + +static void __nfs_access_zap_cache(struct inode *inode) { struct nfs_inode *nfsi = NFS_I(inode); - struct nfs_access_entry *cache = &nfsi->cache_access; + struct rb_root *root_node = &nfsi->access_cache; + struct rb_node *n, *dispose = NULL; + struct nfs_access_entry *entry; + + /* Unhook entries from the cache */ + while ((n = rb_first(root_node)) != NULL) { + entry = rb_entry(n, struct nfs_access_entry, rb_node); + rb_erase(n, root_node); + n->rb_left = dispose; + dispose = n; + } + nfsi->cache_validity &= ~NFS_INO_INVALID_ACCESS; + spin_unlock(&inode->i_lock); - if (cache->cred != cred - || time_after(jiffies, cache->jiffies + NFS_ATTRTIMEO(inode)) - || (nfsi->cache_validity & NFS_INO_INVALID_ACCESS)) - return -ENOENT; - memcpy(res, cache, sizeof(*res)); - return 0; + /* Now kill them all! */ + while (dispose != NULL) { + n = dispose; + dispose = n->rb_left; + nfs_access_free_entry(rb_entry(n, struct nfs_access_entry, rb_node)); + } } -void nfs_access_add_cache(struct inode *inode, struct nfs_access_entry *set) +void nfs_access_zap_cache(struct inode *inode) { - struct nfs_inode *nfsi = NFS_I(inode); - struct nfs_access_entry *cache = &nfsi->cache_access; + spin_lock(&inode->i_lock); + /* This will release the spinlock */ + __nfs_access_zap_cache(inode); +} - if (cache->cred != set->cred) { - if (cache->cred) - put_rpccred(cache->cred); - cache->cred = get_rpccred(set->cred); +static struct nfs_access_entry *nfs_access_search_rbtree(struct inode *inode, struct rpc_cred *cred) +{ + struct rb_node *n = NFS_I(inode)->access_cache.rb_node; + struct nfs_access_entry *entry; + + while (n != NULL) { + entry = rb_entry(n, struct nfs_access_entry, rb_node); + + if (cred < entry->cred) + n = n->rb_left; + else if (cred > entry->cred) + n = n->rb_right; + else + return entry; } - /* FIXME: replace current access_cache BKL reliance with inode->i_lock */ + return NULL; +} + +int nfs_access_get_cached(struct inode *inode, struct rpc_cred *cred, struct nfs_access_entry *res) +{ + struct nfs_inode *nfsi = NFS_I(inode); + struct nfs_access_entry *cache; + int err = -ENOENT; + spin_lock(&inode->i_lock); - nfsi->cache_validity &= ~NFS_INO_INVALID_ACCESS; + if (nfsi->cache_validity & NFS_INO_INVALID_ACCESS) + goto out_zap; + cache = nfs_access_search_rbtree(inode, cred); + if (cache == NULL) + goto out; + if (time_after(jiffies, cache->jiffies + NFS_ATTRTIMEO(inode))) + goto out_stale; + res->jiffies = cache->jiffies; + res->cred = cache->cred; + res->mask = cache->mask; + err = 0; +out: + spin_unlock(&inode->i_lock); + return err; +out_stale: + rb_erase(&cache->rb_node, &nfsi->access_cache); + spin_unlock(&inode->i_lock); + nfs_access_free_entry(cache); + return -ENOENT; +out_zap: + /* This will release the spinlock */ + __nfs_access_zap_cache(inode); + return -ENOENT; +} + +static void nfs_access_add_rbtree(struct inode *inode, struct nfs_access_entry *set) +{ + struct rb_root *root_node = &NFS_I(inode)->access_cache; + struct rb_node **p = &root_node->rb_node; + struct rb_node *parent = NULL; + struct nfs_access_entry *entry; + + spin_lock(&inode->i_lock); + while (*p != NULL) { + parent = *p; + entry = rb_entry(parent, struct nfs_access_entry, rb_node); + + if (set->cred < entry->cred) + p = &parent->rb_left; + else if (set->cred > entry->cred) + p = &parent->rb_right; + else + goto found; + } + rb_link_node(&set->rb_node, parent, p); + rb_insert_color(&set->rb_node, root_node); spin_unlock(&inode->i_lock); + return; +found: + rb_replace_node(parent, &set->rb_node, root_node); + spin_unlock(&inode->i_lock); + nfs_access_free_entry(entry); +} + +void nfs_access_add_cache(struct inode *inode, struct nfs_access_entry *set) +{ + struct nfs_access_entry *cache = kmalloc(sizeof(*cache), GFP_KERNEL); + if (cache == NULL) + return; + RB_CLEAR_NODE(&cache->rb_node); cache->jiffies = set->jiffies; + cache->cred = get_rpccred(set->cred); cache->mask = set->mask; + + nfs_access_add_rbtree(inode, cache); } static int nfs_do_access(struct inode *inode, struct rpc_cred *cred, int mask) -- cgit v1.2.3