NFS: Add an asynchronous delegreturn operation for use in nfs_clear_inode
Otherwise, there is a potential deadlock if the last dput() from an NFSv4 close() or other asynchronous operation leads to nfs_clear_inode calling the synchronous delegreturn. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
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99fadcd764
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e6f8107595
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@ -174,11 +174,11 @@ int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct
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return status;
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}
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static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation)
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static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
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{
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int res = 0;
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res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid);
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res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid, issync);
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nfs_free_delegation(delegation);
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return res;
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}
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@ -208,7 +208,7 @@ static int __nfs_inode_return_delegation(struct inode *inode, struct nfs_delegat
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up_read(&clp->cl_sem);
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nfs_msync_inode(inode);
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return nfs_do_return_delegation(inode, delegation);
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return nfs_do_return_delegation(inode, delegation, 1);
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}
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static struct nfs_delegation *nfs_detach_delegation_locked(struct nfs_inode *nfsi, const nfs4_stateid *stateid)
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@ -228,6 +228,27 @@ nomatch:
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return NULL;
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}
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/*
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* This function returns the delegation without reclaiming opens
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* or protecting against delegation reclaims.
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* It is therefore really only safe to be called from
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* nfs4_clear_inode()
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*/
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void nfs_inode_return_delegation_noreclaim(struct inode *inode)
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{
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struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
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struct nfs_inode *nfsi = NFS_I(inode);
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struct nfs_delegation *delegation;
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if (rcu_dereference(nfsi->delegation) != NULL) {
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spin_lock(&clp->cl_lock);
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delegation = nfs_detach_delegation_locked(nfsi, NULL);
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spin_unlock(&clp->cl_lock);
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if (delegation != NULL)
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nfs_do_return_delegation(inode, delegation, 0);
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}
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}
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int nfs_inode_return_delegation(struct inode *inode)
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{
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struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
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@ -388,7 +409,7 @@ static int recall_thread(void *data)
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nfs_msync_inode(inode);
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if (delegation != NULL)
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nfs_do_return_delegation(inode, delegation);
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nfs_do_return_delegation(inode, delegation, 1);
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iput(inode);
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module_put_and_exit(0);
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}
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@ -29,6 +29,7 @@ int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct
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void nfs_inode_reclaim_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res);
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int nfs_inode_return_delegation(struct inode *inode);
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int nfs_async_inode_return_delegation(struct inode *inode, const nfs4_stateid *stateid);
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void nfs_inode_return_delegation_noreclaim(struct inode *inode);
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struct inode *nfs_delegation_find_inode(struct nfs_client *clp, const struct nfs_fh *fhandle);
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void nfs_return_all_delegations(struct super_block *sb);
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@ -39,7 +40,7 @@ void nfs_delegation_mark_reclaim(struct nfs_client *clp);
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void nfs_delegation_reap_unclaimed(struct nfs_client *clp);
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/* NFSv4 delegation-related procedures */
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int nfs4_proc_delegreturn(struct inode *inode, struct rpc_cred *cred, const nfs4_stateid *stateid);
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int nfs4_proc_delegreturn(struct inode *inode, struct rpc_cred *cred, const nfs4_stateid *stateid, int issync);
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int nfs4_open_delegation_recall(struct nfs_open_context *ctx, struct nfs4_state *state, const nfs4_stateid *stateid);
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int nfs4_lock_delegation_recall(struct nfs4_state *state, struct file_lock *fl);
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int nfs4_copy_delegation_stateid(nfs4_stateid *dst, struct inode *inode);
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@ -864,7 +864,6 @@ static int nfs_dentry_delete(struct dentry *dentry)
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*/
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static void nfs_dentry_iput(struct dentry *dentry, struct inode *inode)
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{
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nfs_inode_return_delegation(inode);
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if (S_ISDIR(inode->i_mode))
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/* drop any readdir cache as it could easily be old */
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NFS_I(inode)->cache_validity |= NFS_INO_INVALID_DATA;
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@ -1145,7 +1145,7 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr)
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void nfs4_clear_inode(struct inode *inode)
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{
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/* If we are holding a delegation, return it! */
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nfs_inode_return_delegation(inode);
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nfs_inode_return_delegation_noreclaim(inode);
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/* First call standard NFS clear_inode() code */
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nfs_clear_inode(inode);
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}
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@ -2991,7 +2991,7 @@ static const struct rpc_call_ops nfs4_delegreturn_ops = {
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.rpc_release = nfs4_delegreturn_release,
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};
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static int _nfs4_proc_delegreturn(struct inode *inode, struct rpc_cred *cred, const nfs4_stateid *stateid)
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static int _nfs4_proc_delegreturn(struct inode *inode, struct rpc_cred *cred, const nfs4_stateid *stateid, int issync)
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{
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struct nfs4_delegreturndata *data;
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struct nfs_server *server = NFS_SERVER(inode);
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@ -3006,7 +3006,7 @@ static int _nfs4_proc_delegreturn(struct inode *inode, struct rpc_cred *cred, co
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.callback_ops = &nfs4_delegreturn_ops,
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.flags = RPC_TASK_ASYNC,
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};
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int status;
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int status = 0;
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data = kmalloc(sizeof(*data), GFP_KERNEL);
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if (data == NULL)
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@ -3028,23 +3028,27 @@ static int _nfs4_proc_delegreturn(struct inode *inode, struct rpc_cred *cred, co
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task = rpc_run_task(&task_setup_data);
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if (IS_ERR(task))
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return PTR_ERR(task);
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if (!issync)
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goto out;
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status = nfs4_wait_for_completion_rpc_task(task);
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if (status == 0) {
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if (status != 0)
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goto out;
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status = data->rpc_status;
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if (status == 0)
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if (status != 0)
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goto out;
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nfs_refresh_inode(inode, &data->fattr);
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}
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out:
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rpc_put_task(task);
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return status;
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}
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int nfs4_proc_delegreturn(struct inode *inode, struct rpc_cred *cred, const nfs4_stateid *stateid)
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int nfs4_proc_delegreturn(struct inode *inode, struct rpc_cred *cred, const nfs4_stateid *stateid, int issync)
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{
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struct nfs_server *server = NFS_SERVER(inode);
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struct nfs4_exception exception = { };
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int err;
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do {
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err = _nfs4_proc_delegreturn(inode, cred, stateid);
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err = _nfs4_proc_delegreturn(inode, cred, stateid, issync);
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switch (err) {
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case -NFS4ERR_STALE_STATEID:
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case -NFS4ERR_EXPIRED:
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