1 files changed, 342 insertions, 0 deletions
diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c
new file mode 100644
index 00000000000..5b9c60f9779
--- /dev/null
+++ b/fs/nfs/delegation.c
@@ -0,0 +1,342 @@
+/*
+ * linux/fs/nfs/delegation.c
+ *
+ * Copyright (C) 2004 Trond Myklebust
+ *
+ * NFS file delegation management
+ *
+ */
+#include <linux/config.h>
+#include <linux/completion.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/spinlock.h>
+
+#include <linux/nfs4.h>
+#include <linux/nfs_fs.h>
+#include <linux/nfs_xdr.h>
+
+#include "delegation.h"
+
+static struct nfs_delegation *nfs_alloc_delegation(void)
+{
+	return (struct nfs_delegation *)kmalloc(sizeof(struct nfs_delegation), GFP_KERNEL);
+}
+
+static void nfs_free_delegation(struct nfs_delegation *delegation)
+{
+	if (delegation->cred)
+		put_rpccred(delegation->cred);
+	kfree(delegation);
+}
+
+static void nfs_delegation_claim_opens(struct inode *inode)
+{
+	struct nfs_inode *nfsi = NFS_I(inode);
+	struct nfs_open_context *ctx;
+	struct nfs4_state *state;
+
+again:
+	spin_lock(&inode->i_lock);
+	list_for_each_entry(ctx, &nfsi->open_files, list) {
+		state = ctx->state;
+		if (state == NULL)
+			continue;
+		if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
+			continue;
+		get_nfs_open_context(ctx);
+		spin_unlock(&inode->i_lock);
+		if (nfs4_open_delegation_recall(ctx->dentry, state) < 0)
+			return;
+		put_nfs_open_context(ctx);
+		goto again;
+	}
+	spin_unlock(&inode->i_lock);
+}
+
+/*
+ * Set up a delegation on an inode
+ */
+void nfs_inode_reclaim_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
+{
+	struct nfs_delegation *delegation = NFS_I(inode)->delegation;
+
+	if (delegation == NULL)
+		return;
+	memcpy(delegation->stateid.data, res->delegation.data,
+			sizeof(delegation->stateid.data));
+	delegation->type = res->delegation_type;
+	delegation->maxsize = res->maxsize;
+	put_rpccred(cred);
+	delegation->cred = get_rpccred(cred);
+	delegation->flags &= ~NFS_DELEGATION_NEED_RECLAIM;
+	NFS_I(inode)->delegation_state = delegation->type;
+	smp_wmb();
+}
+
+/*
+ * Set up a delegation on an inode
+ */
+int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
+{
+	struct nfs4_client *clp = NFS_SERVER(inode)->nfs4_state;
+	struct nfs_inode *nfsi = NFS_I(inode);
+	struct nfs_delegation *delegation;
+	int status = 0;
+
+	delegation = nfs_alloc_delegation();
+	if (delegation == NULL)
+		return -ENOMEM;
+	memcpy(delegation->stateid.data, res->delegation.data,
+			sizeof(delegation->stateid.data));
+	delegation->type = res->delegation_type;
+	delegation->maxsize = res->maxsize;
+	delegation->cred = get_rpccred(cred);
+	delegation->inode = inode;
+
+	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 (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));
+			status = -EIO;
+		}
+	}
+	spin_unlock(&clp->cl_lock);
+	if (delegation != NULL)
+		kfree(delegation);
+	return status;
+}
+
+static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation)
+{
+	int res = 0;
+
+	__nfs_revalidate_inode(NFS_SERVER(inode), inode);
+
+	res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid);
+	nfs_free_delegation(delegation);
+	return res;
+}
+
+/* Sync all data to disk upon delegation return */
+static void nfs_msync_inode(struct inode *inode)
+{
+	filemap_fdatawrite(inode->i_mapping);
+	nfs_wb_all(inode);
+	filemap_fdatawait(inode->i_mapping);
+}
+
+/*
+ * Basic procedure for returning a delegation to the server
+ */
+int nfs_inode_return_delegation(struct inode *inode)
+{
+	struct nfs4_client *clp = NFS_SERVER(inode)->nfs4_state;
+	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);
+	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 all delegations associated to a super block
+ */
+void nfs_return_all_delegations(struct super_block *sb)
+{
+	struct nfs4_client *clp = NFS_SB(sb)->nfs4_state;
+	struct nfs_delegation *delegation;
+	struct inode *inode;
+
+	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);
+		if (inode == NULL)
+			continue;
+		spin_unlock(&clp->cl_lock);
+		nfs_inode_return_delegation(inode);
+		iput(inode);
+		goto restart;
+	}
+	spin_unlock(&clp->cl_lock);
+}
+
+/*
+ * Return all delegations following an NFS4ERR_CB_PATH_DOWN error.
+ */
+void nfs_handle_cb_pathdown(struct nfs4_client *clp)
+{
+	struct nfs_delegation *delegation;
+	struct inode *inode;
+
+	if (clp == NULL)
+		return;
+restart:
+	spin_lock(&clp->cl_lock);
+	list_for_each_entry(delegation, &clp->cl_delegations, super_list) {
+		inode = igrab(delegation->inode);
+		if (inode == NULL)
+			continue;
+		spin_unlock(&clp->cl_lock);
+		nfs_inode_return_delegation(inode);
+		iput(inode);
+		goto restart;
+	}
+	spin_unlock(&clp->cl_lock);
+}
+
+struct recall_threadargs {
+	struct inode *inode;
+	struct nfs4_client *clp;
+	const nfs4_stateid *stateid;
+
+	struct completion started;
+	int result;
+};
+
+static int recall_thread(void *data)
+{
+	struct recall_threadargs *args = (struct recall_threadargs *)data;
+	struct inode *inode = igrab(args->inode);
+	struct nfs4_client *clp = NFS_SERVER(inode)->nfs4_state;
+	struct nfs_inode *nfsi = NFS_I(inode);
+	struct nfs_delegation *delegation;
+
+	daemonize("nfsv4-delegreturn");
+
+	nfs_msync_inode(inode);
+	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;
+		args->result = 0;
+	} else {
+		delegation = NULL;
+		args->result = -ENOENT;
+	}
+	spin_unlock(&clp->cl_lock);
+	complete(&args->started);
+	nfs_delegation_claim_opens(inode);
+	up_write(&nfsi->rwsem);
+	up_read(&clp->cl_sem);
+	nfs_msync_inode(inode);
+
+	if (delegation != NULL)
+		nfs_do_return_delegation(inode, delegation);
+	iput(inode);
+	module_put_and_exit(0);
+}
+
+/*
+ * Asynchronous delegation recall!
+ */
+int nfs_async_inode_return_delegation(struct inode *inode, const nfs4_stateid *stateid)
+{
+	struct recall_threadargs data = {
+		.inode = inode,
+		.stateid = stateid,
+	};
+	int status;
+
+	init_completion(&data.started);
+	__module_get(THIS_MODULE);
+	status = kernel_thread(recall_thread, &data, CLONE_KERNEL);
+	if (status < 0)
+		goto out_module_put;
+	wait_for_completion(&data.started);
+	return data.result;
+out_module_put:
+	module_put(THIS_MODULE);
+	return status;
+}
+
+/*
+ * Retrieve the inode associated with a delegation
+ */
+struct inode *nfs_delegation_find_inode(struct nfs4_client *clp, const struct nfs_fh *fhandle)
+{
+	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) {
+			res = igrab(delegation->inode);
+			break;
+		}
+	}
+	spin_unlock(&clp->cl_lock);
+	return res;
+}
+
+/*
+ * Mark all delegations as needing to be reclaimed
+ */
+void nfs_delegation_mark_reclaim(struct nfs4_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);
+}
+
+/*
+ * Reap all unclaimed delegations after reboot recovery is done
+ */
+void nfs_delegation_reap_unclaimed(struct nfs4_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)
+			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);
+	}
+}