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NFS: Add a new ACCESS rpc call cache to the linux nfs client

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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 <Trond.Myklebust@netapp.com>
This commit is contained in:
Trond Myklebust
2006-07-25 11:28:18 -04:00
parent 3eeab61aa3
commit 1c3c07e9f6
3 changed files with 126 additions and 29 deletions
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137
fs/nfs/dir.c
View File

@@ -1638,35 +1638,134 @@ out:
return error;
}
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 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);
/* 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_zap_cache(struct inode *inode)
{
spin_lock(&inode->i_lock);
/* This will release the spinlock */
__nfs_access_zap_cache(inode);
}
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;
}
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 = &nfsi->cache_access;
struct nfs_access_entry *cache;
int err = -ENOENT;
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;
spin_lock(&inode->i_lock);
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_inode *nfsi = NFS_I(inode);
struct nfs_access_entry *cache = &nfsi->cache_access;
if (cache->cred != set->cred) {
if (cache->cred)
put_rpccred(cache->cred);
cache->cred = get_rpccred(set->cred);
}
/* FIXME: replace current access_cache BKL reliance with inode->i_lock */
spin_lock(&inode->i_lock);
nfsi->cache_validity &= ~NFS_INO_INVALID_ACCESS;
spin_unlock(&inode->i_lock);
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)