]> err.no Git - linux-2.6/commitdiff
NFSv4: Check for the existence of a delegation in nfs4_open_prepare()
authorTrond Myklebust <Trond.Myklebust@netapp.com>
Thu, 5 Jul 2007 23:02:21 +0000 (19:02 -0400)
committerTrond Myklebust <Trond.Myklebust@netapp.com>
Wed, 11 Jul 2007 03:40:43 +0000 (23:40 -0400)
We should not be calling open() on an inode that has a delegation unless
we're doing a reclaim.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
fs/nfs/nfs4proc.c

index 05afb7ba3bc454e727034eff24a4cb9c9efcde38..ea332e831d75d443c7673271e8f79523397cbf1f 100644 (file)
@@ -65,6 +65,7 @@ static int nfs4_async_handle_error(struct rpc_task *, const struct nfs_server *)
 static int _nfs4_proc_access(struct inode *inode, struct nfs_access_entry *entry);
 static int nfs4_handle_exception(const struct nfs_server *server, int errorcode, struct nfs4_exception *exception);
 static int nfs4_wait_clnt_recover(struct rpc_clnt *clnt, struct nfs_client *clp);
+static int _nfs4_do_access(struct inode *inode, struct rpc_cred *cred, int openflags);
 
 /* Prevent leaks of NFSv4 errors into userland */
 int nfs4_map_errors(int err)
@@ -224,6 +225,7 @@ struct nfs4_opendata {
        struct path path;
        struct dentry *dir;
        struct nfs4_state_owner *owner;
+       struct nfs4_state *state;
        struct iattr attrs;
        unsigned long timestamp;
        unsigned int rpc_done : 1;
@@ -296,6 +298,8 @@ static void nfs4_opendata_free(struct kref *kref)
                        struct nfs4_opendata, kref);
 
        nfs_free_seqid(p->o_arg.seqid);
+       if (p->state != NULL)
+               nfs4_put_open_state(p->state);
        nfs4_put_state_owner(p->owner);
        dput(p->dir);
        dput(p->path.dentry);
@@ -320,6 +324,15 @@ static int nfs4_wait_for_completion_rpc_task(struct rpc_task *task)
        return ret;
 }
 
+static int can_open_delegated(struct nfs_delegation *delegation, mode_t open_flags)
+{
+       if ((delegation->type & open_flags) != open_flags)
+               return 0;
+       if (delegation->flags & NFS_DELEGATION_NEED_RECLAIM)
+               return 0;
+       return 1;
+}
+
 static void update_open_stateflags(struct nfs4_state *state, mode_t open_flags)
 {
        switch (open_flags) {
@@ -380,6 +393,65 @@ static void update_open_stateid(struct nfs4_state *state, nfs4_stateid *open_sta
        spin_unlock(&state->owner->so_lock);
 }
 
+static void nfs4_return_incompatible_delegation(struct inode *inode, mode_t open_flags)
+{
+       struct nfs_delegation *delegation;
+
+       rcu_read_lock();
+       delegation = rcu_dereference(NFS_I(inode)->delegation);
+       if (delegation == NULL || (delegation->type & open_flags) == open_flags) {
+               rcu_read_unlock();
+               return;
+       }
+       rcu_read_unlock();
+       nfs_inode_return_delegation(inode);
+}
+
+static struct nfs4_state *nfs4_try_open_delegated(struct nfs4_opendata *opendata)
+{
+       struct nfs4_state *state = opendata->state;
+       struct nfs_inode *nfsi = NFS_I(state->inode);
+       struct nfs_delegation *delegation;
+       int open_mode = opendata->o_arg.open_flags & (FMODE_READ|FMODE_WRITE|O_EXCL);
+       nfs4_stateid stateid;
+       int ret = -EAGAIN;
+
+       rcu_read_lock();
+       delegation = rcu_dereference(nfsi->delegation);
+       if (delegation == NULL)
+               goto out_unlock;
+       for (;;) {
+               if (!can_open_delegated(delegation, open_mode))
+                       break;
+               /* Save the delegation */
+               memcpy(stateid.data, delegation->stateid.data, sizeof(stateid.data));
+               rcu_read_unlock();
+               lock_kernel();
+               ret = _nfs4_do_access(state->inode, state->owner->so_cred, open_mode);
+               unlock_kernel();
+               if (ret != 0)
+                       goto out;
+               ret = -EAGAIN;
+               rcu_read_lock();
+               delegation = rcu_dereference(nfsi->delegation);
+               if (delegation == NULL)
+                       break;
+               /* Is the delegation still valid? */
+               if (memcmp(stateid.data, delegation->stateid.data, sizeof(stateid.data)) != 0)
+                       continue;
+               rcu_read_unlock();
+               update_open_stateid(state, NULL, &stateid, open_mode);
+               goto out_return_state;
+       }
+out_unlock:
+       rcu_read_unlock();
+out:
+       return ERR_PTR(ret);
+out_return_state:
+       atomic_inc(&state->count);
+       return state;
+}
+
 static struct nfs4_state *nfs4_opendata_to_nfs4_state(struct nfs4_opendata *data)
 {
        struct inode *inode;
@@ -388,6 +460,11 @@ static struct nfs4_state *nfs4_opendata_to_nfs4_state(struct nfs4_opendata *data
        nfs4_stateid *deleg_stateid = NULL;
        int ret;
 
+       if (!data->rpc_done) {
+               state = nfs4_try_open_delegated(data);
+               goto out;
+       }
+
        ret = -EAGAIN;
        if (!(data->f_attr.valid & NFS_ATTR_FATTR))
                goto err;
@@ -423,6 +500,7 @@ static struct nfs4_state *nfs4_opendata_to_nfs4_state(struct nfs4_opendata *data
        update_open_stateid(state, &data->o_res.stateid, deleg_stateid, data->o_arg.open_flags);
        rcu_read_unlock();
        iput(inode);
+out:
        return state;
 err_put_inode:
        iput(inode);
@@ -690,6 +768,23 @@ static void nfs4_open_prepare(struct rpc_task *task, void *calldata)
        
        if (nfs_wait_on_sequence(data->o_arg.seqid, task) != 0)
                return;
+       /*
+        * Check if we still need to send an OPEN call, or if we can use
+        * a delegation instead.
+        */
+       if (data->state != NULL) {
+               struct nfs_delegation *delegation;
+
+               rcu_read_lock();
+               delegation = rcu_dereference(NFS_I(data->state->inode)->delegation);
+               if (delegation != NULL &&
+                  (delegation->flags & NFS_DELEGATION_NEED_RECLAIM) == 0) {
+                       rcu_read_unlock();
+                       task->tk_action = NULL;
+                       return;
+               }
+               rcu_read_unlock();
+       }
        /* Update sequence id. */
        data->o_arg.id = sp->so_owner_id.id;
        data->o_arg.clientid = sp->so_client->cl_clientid;
@@ -906,90 +1001,6 @@ static int nfs4_open_expired(struct nfs4_state_owner *sp, struct nfs4_state *sta
        return ret;
 }
 
-/*
- * Returns a referenced nfs4_state if there is an open delegation on the file
- */
-static int _nfs4_open_delegated(struct inode *inode, int flags, struct rpc_cred *cred, struct nfs4_state **res)
-{
-       struct nfs_delegation *delegation;
-       struct nfs_server *server = NFS_SERVER(inode);
-       struct nfs_client *clp = server->nfs_client;
-       struct nfs_inode *nfsi = NFS_I(inode);
-       struct nfs4_state_owner *sp = NULL;
-       struct nfs4_state *state = NULL;
-       int open_flags = flags & (FMODE_READ|FMODE_WRITE);
-       int err;
-
-       err = -ENOMEM;
-       if (!(sp = nfs4_get_state_owner(server, cred))) {
-               dprintk("%s: nfs4_get_state_owner failed!\n", __FUNCTION__);
-               return err;
-       }
-       err = nfs4_recover_expired_lease(server);
-       if (err != 0)
-               goto out_put_state_owner;
-       /* Protect against reboot recovery - NOTE ORDER! */
-       down_read(&clp->cl_sem);
-       /* Protect against delegation recall */
-       down_read(&nfsi->rwsem);
-       delegation = NFS_I(inode)->delegation;
-       err = -ENOENT;
-       if (delegation == NULL || (delegation->type & open_flags) != open_flags)
-               goto out_err;
-       err = -ENOMEM;
-       state = nfs4_get_open_state(inode, sp);
-       if (state == NULL)
-               goto out_err;
-
-       err = -ENOENT;
-       if ((state->state & open_flags) == open_flags) {
-               spin_lock(&inode->i_lock);
-               update_open_stateflags(state, open_flags);
-               spin_unlock(&inode->i_lock);
-               goto out_ok;
-       } else if (state->state != 0)
-               goto out_put_open_state;
-
-       lock_kernel();
-       err = _nfs4_do_access(inode, cred, open_flags);
-       unlock_kernel();
-       if (err != 0)
-               goto out_put_open_state;
-       update_open_stateid(state, NULL, &delegation->stateid, open_flags);
-out_ok:
-       nfs4_put_state_owner(sp);
-       up_read(&nfsi->rwsem);
-       up_read(&clp->cl_sem);
-       *res = state;
-       return 0;
-out_put_open_state:
-       nfs4_put_open_state(state);
-out_err:
-       up_read(&nfsi->rwsem);
-       up_read(&clp->cl_sem);
-       if (err != -EACCES)
-               nfs_inode_return_delegation(inode);
-out_put_state_owner:
-       nfs4_put_state_owner(sp);
-       return err;
-}
-
-static struct nfs4_state *nfs4_open_delegated(struct inode *inode, int flags, struct rpc_cred *cred)
-{
-       struct nfs4_exception exception = { };
-       struct nfs4_state *res = ERR_PTR(-EIO);
-       int err;
-
-       do {
-               err = _nfs4_open_delegated(inode, flags, cred, &res);
-               if (err == 0)
-                       break;
-               res = ERR_PTR(nfs4_handle_exception(NFS_SERVER(inode),
-                                       err, &exception));
-       } while (exception.retry);
-       return res;
-}
-
 /*
  * on an EXCLUSIVE create, the server should send back a bitmask with FATTR4-*
  * fields corresponding to attributes that were used to store the verifier.
@@ -1016,7 +1027,7 @@ static int _nfs4_do_open(struct inode *dir, struct path *path, int flags, struct
        struct nfs_server       *server = NFS_SERVER(dir);
        struct nfs_client *clp = server->nfs_client;
        struct nfs4_opendata *opendata;
-       int                     status;
+       int status;
 
        /* Protect against reboot recovery conflicts */
        status = -ENOMEM;
@@ -1027,12 +1038,17 @@ static int _nfs4_do_open(struct inode *dir, struct path *path, int flags, struct
        status = nfs4_recover_expired_lease(server);
        if (status != 0)
                goto err_put_state_owner;
+       if (path->dentry->d_inode != NULL)
+               nfs4_return_incompatible_delegation(path->dentry->d_inode, flags & (FMODE_READ|FMODE_WRITE));
        down_read(&clp->cl_sem);
        status = -ENOMEM;
        opendata = nfs4_opendata_alloc(path, sp, flags, sattr);
        if (opendata == NULL)
                goto err_release_rwsem;
 
+       if (path->dentry->d_inode != NULL)
+               opendata->state = nfs4_get_open_state(path->dentry->d_inode, sp);
+
        status = _nfs4_proc_open(opendata);
        if (status != 0)
                goto err_opendata_put;
@@ -1099,6 +1115,11 @@ static struct nfs4_state *nfs4_do_open(struct inode *dir, struct path *path, int
                        exception.retry = 1;
                        continue;
                }
+               if (status == -EAGAIN) {
+                       /* We must have found a delegation */
+                       exception.retry = 1;
+                       continue;
+               }
                res = ERR_PTR(nfs4_handle_exception(NFS_SERVER(dir),
                                        status, &exception));
        } while (exception.retry);
@@ -1390,9 +1411,7 @@ nfs4_open_revalidate(struct inode *dir, struct dentry *dentry, int openflags, st
        cred = rpcauth_lookupcred(NFS_CLIENT(dir)->cl_auth, 0);
        if (IS_ERR(cred))
                return PTR_ERR(cred);
-       state = nfs4_open_delegated(dentry->d_inode, openflags, cred);
-       if (IS_ERR(state))
-               state = nfs4_do_open(dir, &path, openflags, NULL, cred);
+       state = nfs4_do_open(dir, &path, openflags, NULL, cred);
        put_rpccred(cred);
        if (IS_ERR(state)) {
                switch (PTR_ERR(state)) {