NFS: Use atomic bitops when changing struct nfs_delegation->flags
[safe/jmp/linux-2.6] / fs / nfs / delegation.c
index 7f37d1b..646ba3e 100644 (file)
 #include "delegation.h"
 #include "internal.h"
 
-static void nfs_free_delegation(struct nfs_delegation *delegation)
+static void nfs_do_free_delegation(struct nfs_delegation *delegation)
 {
-       if (delegation->cred)
-               put_rpccred(delegation->cred);
        kfree(delegation);
 }
 
+static void nfs_free_delegation_callback(struct rcu_head *head)
+{
+       struct nfs_delegation *delegation = container_of(head, struct nfs_delegation, rcu);
+
+       nfs_do_free_delegation(delegation);
+}
+
+static void nfs_free_delegation(struct nfs_delegation *delegation)
+{
+       struct rpc_cred *cred;
+
+       cred = rcu_dereference(delegation->cred);
+       rcu_assign_pointer(delegation->cred, NULL);
+       call_rcu(&delegation->rcu, nfs_free_delegation_callback);
+       if (cred)
+               put_rpccred(cred);
+}
+
 static int nfs_delegation_claim_locks(struct nfs_open_context *ctx, struct nfs4_state *state)
 {
        struct inode *inode = state->inode;
        struct file_lock *fl;
        int status;
 
-       for (fl = inode->i_flock; fl != 0; fl = fl->fl_next) {
+       for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
                if (!(fl->fl_flags & (FL_POSIX|FL_FLOCK)))
                        continue;
-               if ((struct nfs_open_context *)fl->fl_file->private_data != ctx)
+               if (nfs_file_open_context(fl->fl_file) != ctx)
                        continue;
                status = nfs4_lock_delegation_recall(state, fl);
                if (status >= 0)
@@ -44,7 +60,7 @@ static int nfs_delegation_claim_locks(struct nfs_open_context *ctx, struct nfs4_
                switch (status) {
                        default:
                                printk(KERN_ERR "%s: unhandled error %d.\n",
-                                               __FUNCTION__, status);
+                                               __func__, status);
                        case -NFS4ERR_EXPIRED:
                                /* kill_proc(fl->fl_pid, SIGLOST, 1); */
                        case -NFS4ERR_STALE_CLIENTID:
@@ -57,7 +73,7 @@ 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 +88,11 @@ 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);
@@ -91,6 +109,7 @@ again:
 void nfs_inode_reclaim_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
 {
        struct nfs_delegation *delegation = NFS_I(inode)->delegation;
+       struct rpc_cred *oldcred;
 
        if (delegation == NULL)
                return;
@@ -98,11 +117,54 @@ void nfs_inode_reclaim_delegation(struct inode *inode, struct rpc_cred *cred, st
                        sizeof(delegation->stateid.data));
        delegation->type = res->delegation_type;
        delegation->maxsize = res->maxsize;
-       put_rpccred(cred);
+       oldcred = delegation->cred;
        delegation->cred = get_rpccred(cred);
-       delegation->flags &= ~NFS_DELEGATION_NEED_RECLAIM;
+       clear_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
        NFS_I(inode)->delegation_state = delegation->type;
        smp_wmb();
+       put_rpccred(oldcred);
+}
+
+static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
+{
+       int res = 0;
+
+       res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid, issync);
+       nfs_free_delegation(delegation);
+       return res;
+}
+
+static struct inode *nfs_delegation_grab_inode(struct nfs_delegation *delegation)
+{
+       struct inode *inode = NULL;
+
+       spin_lock(&delegation->lock);
+       if (delegation->inode != NULL)
+               inode = igrab(delegation->inode);
+       spin_unlock(&delegation->lock);
+       return inode;
+}
+
+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;
+       spin_lock(&delegation->lock);
+       if (stateid != NULL && memcmp(delegation->stateid.data, stateid->data,
+                               sizeof(delegation->stateid.data)) != 0)
+               goto nomatch_unlock;
+       list_del_rcu(&delegation->super_list);
+       delegation->inode = NULL;
+       nfsi->delegation_state = 0;
+       rcu_assign_pointer(nfsi->delegation, NULL);
+       spin_unlock(&delegation->lock);
+       return delegation;
+nomatch_unlock:
+       spin_unlock(&delegation->lock);
+nomatch:
+       return NULL;
 }
 
 /*
@@ -113,12 +175,9 @@ int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct
        struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
        struct nfs_inode *nfsi = NFS_I(inode);
        struct nfs_delegation *delegation;
+       struct nfs_delegation *freeme = NULL;
        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;
@@ -129,34 +188,46 @@ int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct
        delegation->change_attr = nfsi->change_attr;
        delegation->cred = get_rpccred(cred);
        delegation->inode = inode;
+       spin_lock_init(&delegation->lock);
 
        spin_lock(&clp->cl_lock);
-       if (nfsi->delegation == NULL) {
-               list_add(&delegation->super_list, &clp->cl_delegations);
-               nfsi->delegation = delegation;
-               nfsi->delegation_state = delegation->type;
-               delegation = NULL;
-       } else {
+       if (rcu_dereference(nfsi->delegation) != NULL) {
                if (memcmp(&delegation->stateid, &nfsi->delegation->stateid,
-                                       sizeof(delegation->stateid)) != 0 ||
-                               delegation->type != nfsi->delegation->type) {
-                       printk("%s: server %u.%u.%u.%u, handed out a duplicate delegation!\n",
-                                       __FUNCTION__, NIPQUAD(clp->cl_addr.sin_addr));
-                       status = -EIO;
+                                       sizeof(delegation->stateid)) == 0 &&
+                               delegation->type == nfsi->delegation->type) {
+                       goto out;
                }
+               /*
+                * Deal with broken servers that hand out two
+                * delegations for the same file.
+                */
+               dfprintk(FILE, "%s: server %s handed out "
+                               "a duplicate delegation!\n",
+                               __func__, clp->cl_hostname);
+               if (delegation->type <= nfsi->delegation->type) {
+                       freeme = delegation;
+                       delegation = NULL;
+                       goto out;
+               }
+               freeme = nfs_detach_delegation_locked(nfsi, NULL);
        }
-       spin_unlock(&clp->cl_lock);
-       kfree(delegation);
-       return status;
-}
+       list_add_rcu(&delegation->super_list, &clp->cl_delegations);
+       nfsi->delegation_state = delegation->type;
+       rcu_assign_pointer(nfsi->delegation, delegation);
+       delegation = NULL;
 
-static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation)
-{
-       int res = 0;
+       /* 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);
 
-       res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid);
-       nfs_free_delegation(delegation);
-       return res;
+out:
+       spin_unlock(&clp->cl_lock);
+       if (delegation != NULL)
+               nfs_free_delegation(delegation);
+       if (freeme != NULL)
+               nfs_do_return_delegation(inode, freeme, 0);
+       return status;
 }
 
 /* Sync all data to disk upon delegation return */
@@ -170,33 +241,59 @@ 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, 1);
+}
+
+/*
+ * This function returns the delegation without reclaiming opens
+ * or protecting against delegation reclaims.
+ * It is therefore really only safe to be called from
+ * nfs4_clear_inode()
+ */
+void nfs_inode_return_delegation_noreclaim(struct inode *inode)
+{
+       struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
+       struct nfs_inode *nfsi = NFS_I(inode);
+       struct nfs_delegation *delegation;
+
+       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)
+                       nfs_do_return_delegation(inode, delegation, 0);
+       }
+}
+
+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 +308,25 @@ 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) {
-               if (delegation->inode->i_sb != sb)
-                       continue;
-               inode = igrab(delegation->inode);
+       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);
+               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);
-               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 +337,26 @@ 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) {
-               inode = igrab(delegation->inode);
+       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);
-               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);
 }
@@ -261,8 +368,9 @@ void nfs_expire_all_delegations(struct nfs_client *clp)
        __module_get(THIS_MODULE);
        atomic_inc(&clp->cl_count);
        task = kthread_run(nfs_do_expire_all_delegations, clp,
-                       "%u.%u.%u.%u-delegreturn",
-                       NIPQUAD(clp->cl_addr.sin_addr));
+                               "%s-delegreturn",
+                               rpc_peeraddr2str(clp->cl_rpcclient,
+                                                       RPC_DISPLAY_ADDR));
        if (!IS_ERR(task))
                return;
        nfs_put_client(clp);
@@ -280,17 +388,21 @@ 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) {
-               inode = igrab(delegation->inode);
+       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);
-               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 {
@@ -316,27 +428,20 @@ 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);
 
        if (delegation != NULL)
-               nfs_do_return_delegation(inode, delegation);
+               nfs_do_return_delegation(inode, delegation, 1);
        iput(inode);
        module_put_and_exit(0);
 }
@@ -371,14 +476,18 @@ 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) {
-               if (nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
+       rcu_read_lock();
+       list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
+               spin_lock(&delegation->lock);
+               if (delegation->inode != NULL &&
+                   nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
                        res = igrab(delegation->inode);
-                       break;
                }
+               spin_unlock(&delegation->lock);
+               if (res != NULL)
+                       break;
        }
-       spin_unlock(&clp->cl_lock);
+       rcu_read_unlock();
        return res;
 }
 
@@ -388,10 +497,10 @@ 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)
-               delegation->flags |= NFS_DELEGATION_NEED_RECLAIM;
-       spin_unlock(&clp->cl_lock);
+       rcu_read_lock();
+       list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list)
+               set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
+       rcu_read_unlock();
 }
 
 /*
@@ -399,39 +508,40 @@ 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) {
-               if ((delegation->flags & NFS_DELEGATION_NEED_RECLAIM) == 0)
+       struct nfs_delegation *delegation;
+       struct inode *inode;
+restart:
+       rcu_read_lock();
+       list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
+               if (test_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags) == 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);
+               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_free_delegation(delegation);
+               iput(inode);
+               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;
 }