1 files changed, 110 insertions, 76 deletions

diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c
index 7f37d1bea83f..20ac403469a0 100644
--- a/fs/nfs/delegation.c
+++ b/fs/nfs/delegation.c
@@ -27,6 +27,13 @@ static void nfs_free_delegation(struct nfs_delegation *delegation)
         kfree(delegation);
 }
 
+static void nfs_free_delegation_callback(struct rcu_head *head)
+{
+        struct nfs_delegation *delegation = container_of(head, struct nfs_delegation, rcu);
+
+        nfs_free_delegation(delegation);
+}
+
 static int nfs_delegation_claim_locks(struct nfs_open_context *ctx, struct nfs4_state *state)
 {
         struct inode *inode = state->inode;
@@ -57,7 +64,7 @@ out_err:
         return status;
 }
 
-static void nfs_delegation_claim_opens(struct inode *inode)
+static void nfs_delegation_claim_opens(struct inode *inode, const nfs4_stateid *stateid)
 {
         struct nfs_inode *nfsi = NFS_I(inode);
         struct nfs_open_context *ctx;
@@ -72,9 +79,11 @@ again:
                         continue;
                 if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
                         continue;
+                if (memcmp(state->stateid.data, stateid->data, sizeof(state->stateid.data)) != 0)
+                        continue;
                 get_nfs_open_context(ctx);
                 spin_unlock(&inode->i_lock);
-                err = nfs4_open_delegation_recall(ctx->dentry, state);
+                err = nfs4_open_delegation_recall(ctx, state, stateid);
                 if (err >= 0)
                         err = nfs_delegation_claim_locks(ctx, state);
                 put_nfs_open_context(ctx);
@@ -115,10 +124,6 @@ int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct
         struct nfs_delegation *delegation;
         int status = 0;
 
-        /* Ensure we first revalidate the attributes and page cache! */
-        if ((nfsi->cache_validity & (NFS_INO_REVAL_PAGECACHE|NFS_INO_INVALID_ATTR)))
-                __nfs_revalidate_inode(NFS_SERVER(inode), inode);
-
         delegation = kmalloc(sizeof(*delegation), GFP_KERNEL);
         if (delegation == NULL)
                 return -ENOMEM;
@@ -131,10 +136,10 @@ int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct
         delegation->inode = inode;
 
         spin_lock(&clp->cl_lock);
-        if (nfsi->delegation == NULL) {
-                list_add(&delegation->super_list, &clp->cl_delegations);
-                nfsi->delegation = delegation;
+        if (rcu_dereference(nfsi->delegation) == NULL) {
+                list_add_rcu(&delegation->super_list, &clp->cl_delegations);
                 nfsi->delegation_state = delegation->type;
+                rcu_assign_pointer(nfsi->delegation, delegation);
                 delegation = NULL;
         } else {
                 if (memcmp(&delegation->stateid, &nfsi->delegation->stateid,
@@ -145,6 +150,12 @@ int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct
                         status = -EIO;
                 }
         }
+
+        /* Ensure we revalidate the attributes and page cache! */
+        spin_lock(&inode->i_lock);
+        nfsi->cache_validity |= NFS_INO_REVAL_FORCED;
+        spin_unlock(&inode->i_lock);
+
         spin_unlock(&clp->cl_lock);
         kfree(delegation);
         return status;
@@ -155,7 +166,7 @@ static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *
         int res = 0;
 
         res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid);
-        nfs_free_delegation(delegation);
+        call_rcu(&delegation->rcu, nfs_free_delegation_callback);
         return res;
 }
 
@@ -170,33 +181,55 @@ static void nfs_msync_inode(struct inode *inode)
 /*
  * Basic procedure for returning a delegation to the server
  */
-int __nfs_inode_return_delegation(struct inode *inode)
+static int __nfs_inode_return_delegation(struct inode *inode, struct nfs_delegation *delegation)
 {
         struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
         struct nfs_inode *nfsi = NFS_I(inode);
-        struct nfs_delegation *delegation;
-        int res = 0;
 
         nfs_msync_inode(inode);
         down_read(&clp->cl_sem);
         /* Guard against new delegated open calls */
         down_write(&nfsi->rwsem);
-        spin_lock(&clp->cl_lock);
-        delegation = nfsi->delegation;
-        if (delegation != NULL) {
-                list_del_init(&delegation->super_list);
-                nfsi->delegation = NULL;
-                nfsi->delegation_state = 0;
-        }
-        spin_unlock(&clp->cl_lock);
-        nfs_delegation_claim_opens(inode);
+        nfs_delegation_claim_opens(inode, &delegation->stateid);
         up_write(&nfsi->rwsem);
         up_read(&clp->cl_sem);
         nfs_msync_inode(inode);
 
-        if (delegation != NULL)
-                res = nfs_do_return_delegation(inode, delegation);
-        return res;
+        return nfs_do_return_delegation(inode, delegation);
+}
+
+static struct nfs_delegation *nfs_detach_delegation_locked(struct nfs_inode *nfsi, const nfs4_stateid *stateid)
+{
+        struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
+
+        if (delegation == NULL)
+                goto nomatch;
+        if (stateid != NULL && memcmp(delegation->stateid.data, stateid->data,
+                                sizeof(delegation->stateid.data)) != 0)
+                goto nomatch;
+        list_del_rcu(&delegation->super_list);
+        nfsi->delegation_state = 0;
+        rcu_assign_pointer(nfsi->delegation, NULL);
+        return delegation;
+nomatch:
+        return NULL;
+}
+
+int nfs_inode_return_delegation(struct inode *inode)
+{
+        struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
+        struct nfs_inode *nfsi = NFS_I(inode);
+        struct nfs_delegation *delegation;
+        int err = 0;
+
+        if (rcu_dereference(nfsi->delegation) != NULL) {
+                spin_lock(&clp->cl_lock);
+                delegation = nfs_detach_delegation_locked(nfsi, NULL);
+                spin_unlock(&clp->cl_lock);
+                if (delegation != NULL)
+                        err = __nfs_inode_return_delegation(inode, delegation);
+        }
+        return err;
 }
 
 /*
@@ -211,19 +244,23 @@ void nfs_return_all_delegations(struct super_block *sb)
         if (clp == NULL)
                 return;
 restart:
-        spin_lock(&clp->cl_lock);
-        list_for_each_entry(delegation, &clp->cl_delegations, super_list) {
+        rcu_read_lock();
+        list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
                 if (delegation->inode->i_sb != sb)
                         continue;
                 inode = igrab(delegation->inode);
                 if (inode == NULL)
                         continue;
+                spin_lock(&clp->cl_lock);
+                delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
                 spin_unlock(&clp->cl_lock);
-                nfs_inode_return_delegation(inode);
+                rcu_read_unlock();
+                if (delegation != NULL)
+                        __nfs_inode_return_delegation(inode, delegation);
                 iput(inode);
                 goto restart;
         }
-        spin_unlock(&clp->cl_lock);
+        rcu_read_unlock();
 }
 
 static int nfs_do_expire_all_delegations(void *ptr)
@@ -234,22 +271,26 @@ static int nfs_do_expire_all_delegations(void *ptr)
 
         allow_signal(SIGKILL);
 restart:
-        spin_lock(&clp->cl_lock);
         if (test_bit(NFS4CLNT_STATE_RECOVER, &clp->cl_state) != 0)
                 goto out;
         if (test_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state) == 0)
                 goto out;
-        list_for_each_entry(delegation, &clp->cl_delegations, super_list) {
+        rcu_read_lock();
+        list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
                 inode = igrab(delegation->inode);
                 if (inode == NULL)
                         continue;
+                spin_lock(&clp->cl_lock);
+                delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
                 spin_unlock(&clp->cl_lock);
-                nfs_inode_return_delegation(inode);
+                rcu_read_unlock();
+                if (delegation)
+                        __nfs_inode_return_delegation(inode, delegation);
                 iput(inode);
                 goto restart;
         }
+        rcu_read_unlock();
 out:
-        spin_unlock(&clp->cl_lock);
         nfs_put_client(clp);
         module_put_and_exit(0);
 }
@@ -280,17 +321,21 @@ void nfs_handle_cb_pathdown(struct nfs_client *clp)
         if (clp == NULL)
                 return;
 restart:
-        spin_lock(&clp->cl_lock);
-        list_for_each_entry(delegation, &clp->cl_delegations, super_list) {
+        rcu_read_lock();
+        list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
                 inode = igrab(delegation->inode);
                 if (inode == NULL)
                         continue;
+                spin_lock(&clp->cl_lock);
+                delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
                 spin_unlock(&clp->cl_lock);
-                nfs_inode_return_delegation(inode);
+                rcu_read_unlock();
+                if (delegation != NULL)
+                        __nfs_inode_return_delegation(inode, delegation);
                 iput(inode);
                 goto restart;
         }
-        spin_unlock(&clp->cl_lock);
+        rcu_read_unlock();
 }
 
 struct recall_threadargs {
@@ -316,21 +361,14 @@ static int recall_thread(void *data)
         down_read(&clp->cl_sem);
         down_write(&nfsi->rwsem);
         spin_lock(&clp->cl_lock);
-        delegation = nfsi->delegation;
-        if (delegation != NULL && memcmp(delegation->stateid.data,
-                                args->stateid->data,
-                                sizeof(delegation->stateid.data)) == 0) {
-                list_del_init(&delegation->super_list);
-                nfsi->delegation = NULL;
-                nfsi->delegation_state = 0;
+        delegation = nfs_detach_delegation_locked(nfsi, args->stateid);
+        if (delegation != NULL)
                 args->result = 0;
-        } else {
-                delegation = NULL;
+        else
                 args->result = -ENOENT;
-        }
         spin_unlock(&clp->cl_lock);
         complete(&args->started);
-        nfs_delegation_claim_opens(inode);
+        nfs_delegation_claim_opens(inode, args->stateid);
         up_write(&nfsi->rwsem);
         up_read(&clp->cl_sem);
         nfs_msync_inode(inode);
@@ -371,14 +409,14 @@ struct inode *nfs_delegation_find_inode(struct nfs_client *clp, const struct nfs
 {
         struct nfs_delegation *delegation;
         struct inode *res = NULL;
-        spin_lock(&clp->cl_lock);
-        list_for_each_entry(delegation, &clp->cl_delegations, super_list) {
+        rcu_read_lock();
+        list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
                 if (nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
                         res = igrab(delegation->inode);
                         break;
                 }
         }
-        spin_unlock(&clp->cl_lock);
+        rcu_read_unlock();
         return res;
 }
 
@@ -388,10 +426,10 @@ struct inode *nfs_delegation_find_inode(struct nfs_client *clp, const struct nfs
 void nfs_delegation_mark_reclaim(struct nfs_client *clp)
 {
         struct nfs_delegation *delegation;
-        spin_lock(&clp->cl_lock);
-        list_for_each_entry(delegation, &clp->cl_delegations, super_list)
+        rcu_read_lock();
+        list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list)
                 delegation->flags |= NFS_DELEGATION_NEED_RECLAIM;
-        spin_unlock(&clp->cl_lock);
+        rcu_read_unlock();
 }
 
 /*
@@ -399,39 +437,35 @@ void nfs_delegation_mark_reclaim(struct nfs_client *clp)
  */
 void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
 {
-        struct nfs_delegation *delegation, *n;
-        LIST_HEAD(head);
-        spin_lock(&clp->cl_lock);
-        list_for_each_entry_safe(delegation, n, &clp->cl_delegations, super_list) {
+        struct nfs_delegation *delegation;
+restart:
+        rcu_read_lock();
+        list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
                 if ((delegation->flags & NFS_DELEGATION_NEED_RECLAIM) == 0)
                         continue;
-                list_move(&delegation->super_list, &head);
-                NFS_I(delegation->inode)->delegation = NULL;
-                NFS_I(delegation->inode)->delegation_state = 0;
-        }
-        spin_unlock(&clp->cl_lock);
-        while(!list_empty(&head)) {
-                delegation = list_entry(head.next, struct nfs_delegation, super_list);
-                list_del(&delegation->super_list);
-                nfs_free_delegation(delegation);
+                spin_lock(&clp->cl_lock);
+                delegation = nfs_detach_delegation_locked(NFS_I(delegation->inode), NULL);
+                spin_unlock(&clp->cl_lock);
+                rcu_read_unlock();
+                if (delegation != NULL)
+                        call_rcu(&delegation->rcu, nfs_free_delegation_callback);
+                goto restart;
         }
+        rcu_read_unlock();
 }
 
 int nfs4_copy_delegation_stateid(nfs4_stateid *dst, struct inode *inode)
 {
-        struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
         struct nfs_inode *nfsi = NFS_I(inode);
         struct nfs_delegation *delegation;
-        int res = 0;
+        int ret = 0;
 
-        if (nfsi->delegation_state == 0)
-                return 0;
-        spin_lock(&clp->cl_lock);
-        delegation = nfsi->delegation;
+        rcu_read_lock();
+        delegation = rcu_dereference(nfsi->delegation);
         if (delegation != NULL) {
                 memcpy(dst->data, delegation->stateid.data, sizeof(dst->data));
-                res = 1;
+                ret = 1;
         }
-        spin_unlock(&clp->cl_lock);
-        return res;
+        rcu_read_unlock();
+        return ret;
 }