NFSv4: Clean up the support for returning multiple delegations

Add a flag to mark delegations as requiring return, then run a garbage
collector. In the future, this will allow for more flexible delegation
management, where delegations may be marked for return if it turns out
that they are not being referenced.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c
index ebc06f2da31ad9601c709c185a518fe122783b56..bc9d4f9a788d3fce7cfb130fbd8ebda1578e3b37 100644 (file)
--- a/fs/nfs/delegation.c
+++ b/fs/nfs/delegation.c
@@ -255,6 +255,34 @@ static int __nfs_inode_return_delegation(struct inode *inode, struct nfs_delegat
        return nfs_do_return_delegation(inode, delegation, 1);
 }
 
+/*
+ * Return all delegations that have been marked for return
+ */
+static void nfs_client_return_marked_delegations(struct nfs_client *clp)
+{
+       struct nfs_delegation *delegation;
+       struct inode *inode;
+
+restart:
+       rcu_read_lock();
+       list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
+               if (!test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
+                       continue;
+               inode = nfs_delegation_grab_inode(delegation);
+               if (inode == NULL)
+                       continue;
+               spin_lock(&clp->cl_lock);
+               delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
+               spin_unlock(&clp->cl_lock);
+               rcu_read_unlock();
+               if (delegation != NULL)
+                       __nfs_inode_return_delegation(inode, delegation);
+               iput(inode);
+               goto restart;
+       }
+       rcu_read_unlock();
+}
+
 /*
  * This function returns the delegation without reclaiming opens
  * or protecting against delegation reclaims.
@@ -296,63 +324,46 @@ int nfs_inode_return_delegation(struct inode *inode)
 /*
  * Return all delegations associated to a super block
  */
-void nfs_return_all_delegations(struct super_block *sb)
+void nfs_super_return_all_delegations(struct super_block *sb)
 {
        struct nfs_client *clp = NFS_SB(sb)->nfs_client;
        struct nfs_delegation *delegation;
-       struct inode *inode;
 
        if (clp == NULL)
                return;
-restart:
        rcu_read_lock();
        list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
-               inode = NULL;
                spin_lock(&delegation->lock);
                if (delegation->inode != NULL && delegation->inode->i_sb == sb)
-                       inode = igrab(delegation->inode);
+                       set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
                spin_unlock(&delegation->lock);
-               if (inode == NULL)
-                       continue;
-               spin_lock(&clp->cl_lock);
-               delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
-               spin_unlock(&clp->cl_lock);
-               rcu_read_unlock();
-               if (delegation != NULL)
-                       __nfs_inode_return_delegation(inode, delegation);
-               iput(inode);
-               goto restart;
        }
        rcu_read_unlock();
+       nfs_client_return_marked_delegations(clp);
+}
+
+static void nfs_client_return_all_delegations(struct nfs_client *clp)
+{
+       struct nfs_delegation *delegation;
+
+       rcu_read_lock();
+       list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list)
+               set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
+       rcu_read_unlock();
+       nfs_client_return_marked_delegations(clp);
 }
 
 static int nfs_do_expire_all_delegations(void *ptr)
 {
        struct nfs_client *clp = ptr;
-       struct nfs_delegation *delegation;
-       struct inode *inode;
 
        allow_signal(SIGKILL);
-restart:
+
        if (test_bit(NFS4CLNT_STATE_RECOVER, &clp->cl_state) != 0)
                goto out;
        if (test_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state) == 0)
                goto out;
-       rcu_read_lock();
-       list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
-               inode = nfs_delegation_grab_inode(delegation);
-               if (inode == NULL)
-                       continue;
-               spin_lock(&clp->cl_lock);
-               delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
-               spin_unlock(&clp->cl_lock);
-               rcu_read_unlock();
-               if (delegation)
-                       __nfs_inode_return_delegation(inode, delegation);
-               iput(inode);
-               goto restart;
-       }
-       rcu_read_unlock();
+       nfs_client_return_all_delegations(clp);
 out:
        nfs_put_client(clp);
        module_put_and_exit(0);
@@ -379,27 +390,9 @@ void nfs_expire_all_delegations(struct nfs_client *clp)
  */
 void nfs_handle_cb_pathdown(struct nfs_client *clp)
 {
-       struct nfs_delegation *delegation;
-       struct inode *inode;
-
        if (clp == NULL)
                return;
-restart:
-       rcu_read_lock();
-       list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
-               inode = nfs_delegation_grab_inode(delegation);
-               if (inode == NULL)
-                       continue;
-               spin_lock(&clp->cl_lock);
-               delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
-               spin_unlock(&clp->cl_lock);
-               rcu_read_unlock();
-               if (delegation != NULL)
-                       __nfs_inode_return_delegation(inode, delegation);
-               iput(inode);
-               goto restart;
-       }
-       rcu_read_unlock();
+       nfs_client_return_all_delegations(clp);
 }
 
 struct recall_threadargs {

diff --git a/fs/nfs/delegation.h b/fs/nfs/delegation.h
index 5e9f40e0a7d81f0e1a9708e095e363df6718d359..c772bab12eea67d45232b7580e6c3a8bc34632c1 100644 (file)
--- a/fs/nfs/delegation.h
+++ b/fs/nfs/delegation.h
@@ -20,12 +20,16 @@ struct nfs_delegation {
        int type;
        loff_t maxsize;
        __u64 change_attr;
-#define NFS_DELEGATION_NEED_RECLAIM 0
        unsigned long flags;
        spinlock_t lock;
        struct rcu_head rcu;
 };
 
+enum {
+       NFS_DELEGATION_NEED_RECLAIM = 0,
+       NFS_DELEGATION_RETURN,
+};
+
 int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res);
 void nfs_inode_reclaim_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res);
 int nfs_inode_return_delegation(struct inode *inode);
@@ -33,7 +37,7 @@ int nfs_async_inode_return_delegation(struct inode *inode, const nfs4_stateid *s
 void nfs_inode_return_delegation_noreclaim(struct inode *inode);
 
 struct inode *nfs_delegation_find_inode(struct nfs_client *clp, const struct nfs_fh *fhandle);
-void nfs_return_all_delegations(struct super_block *sb);
+void nfs_super_return_all_delegations(struct super_block *sb);
 void nfs_expire_all_delegations(struct nfs_client *clp);
 void nfs_handle_cb_pathdown(struct nfs_client *clp);
 

diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index d8e062fe76b110a5cc66c8f0098e427e483c49f7..bd4c3dd550df99f7ba8eb5d704ca481f4962ae87 100644 (file)
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -2433,7 +2433,7 @@ static void nfs4_kill_super(struct super_block *sb)
 {
        struct nfs_server *server = NFS_SB(sb);
 
-       nfs_return_all_delegations(sb);
+       nfs_super_return_all_delegations(sb);
        kill_anon_super(sb);
 
        nfs4_renewd_prepare_shutdown(server);