Initial import of modified Linux 2.6.28 tree

Original upstream URL:
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git | branch linux-2.6.28.y

1 files changed, 519 insertions, 0 deletions

diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c
new file mode 100644
index 0000000..cc563cf
--- /dev/null
+++ b/fs/nfs/delegation.c
@@ -0,0 +1,519 @@
+/*
+ * linux/fs/nfs/delegation.c
+ *
+ * Copyright (C) 2004 Trond Myklebust
+ *
+ * NFS file delegation management
+ *
+ */
+#include <linux/completion.h>
+#include <linux/kthread.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 "nfs4_fs.h"
+#include "delegation.h"
+#include "internal.h"
+
+static void nfs_do_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_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 != NULL; fl = fl->fl_next) {
+		if (!(fl->fl_flags & (FL_POSIX|FL_FLOCK)))
+			continue;
+		if (nfs_file_open_context(fl->fl_file) != ctx)
+			continue;
+		status = nfs4_lock_delegation_recall(state, fl);
+		if (status >= 0)
+			continue;
+		switch (status) {
+			default:
+				printk(KERN_ERR "%s: unhandled error %d.\n",
+						__func__, status);
+			case -NFS4ERR_EXPIRED:
+				/* kill_proc(fl->fl_pid, SIGLOST, 1); */
+			case -NFS4ERR_STALE_CLIENTID:
+				nfs4_schedule_state_recovery(NFS_SERVER(inode)->nfs_client);
+				goto out_err;
+		}
+	}
+	return 0;
+out_err:
+	return status;
+}
+
+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;
+	struct nfs4_state *state;
+	int err;
+
+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;
+		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, state, stateid);
+		if (err >= 0)
+			err = nfs_delegation_claim_locks(ctx, state);
+		put_nfs_open_context(ctx);
+		if (err != 0)
+			return;
+		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;
+	struct rpc_cred *oldcred;
+
+	if (delegation == NULL)
+		return;
+	memcpy(delegation->stateid.data, res->delegation.data,
+			sizeof(delegation->stateid.data));
+	delegation->type = res->delegation_type;
+	delegation->maxsize = res->maxsize;
+	oldcred = delegation->cred;
+	delegation->cred = get_rpccred(cred);
+	delegation->flags &= ~NFS_DELEGATION_NEED_RECLAIM;
+	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 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;
+}
+
+/*
+ * Set up a delegation on an inode
+ */
+int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
+{
+	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;
+
+	delegation = kmalloc(sizeof(*delegation), GFP_KERNEL);
+	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->change_attr = nfsi->change_attr;
+	delegation->cred = get_rpccred(cred);
+	delegation->inode = inode;
+
+	spin_lock(&clp->cl_lock);
+	if (rcu_dereference(nfsi->delegation) != NULL) {
+		if (memcmp(&delegation->stateid, &nfsi->delegation->stateid,
+					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);
+	}
+	list_add_rcu(&delegation->super_list, &clp->cl_delegations);
+	nfsi->delegation_state = delegation->type;
+	rcu_assign_pointer(nfsi->delegation, delegation);
+	delegation = NULL;
+
+	/* 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);
+
+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 */
+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
+ */
+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);
+
+	nfs_msync_inode(inode);
+	down_read(&clp->cl_sem);
+	/* Guard against new delegated open calls */
+	down_write(&nfsi->rwsem);
+	nfs_delegation_claim_opens(inode, &delegation->stateid);
+	up_write(&nfsi->rwsem);
+	up_read(&clp->cl_sem);
+	nfs_msync_inode(inode);
+
+	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;
+}
+
+/*
+ * Return all delegations associated to a super block
+ */
+void nfs_return_all_delegations(struct super_block *sb)
+{
+	struct nfs_client *clp = NFS_SB(sb)->nfs_client;
+	struct nfs_delegation *delegation;
+	struct inode *inode;
+
+	if (clp == NULL)
+		return;
+restart:
+	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);
+		rcu_read_unlock();
+		if (delegation != NULL)
+			__nfs_inode_return_delegation(inode, delegation);
+		iput(inode);
+		goto restart;
+	}
+	rcu_read_unlock();
+}
+
+static int nfs_do_expire_all_delegations(void *ptr)
+{
+	struct nfs_client *clp = ptr;
+	struct nfs_delegation *delegation;
+	struct inode *inode;
+
+	allow_signal(SIGKILL);
+restart:
+	if (test_bit(NFS4CLNT_STATE_RECOVER, &clp->cl_state) != 0)
+		goto out;
+	if (test_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state) == 0)
+		goto out;
+	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);
+		rcu_read_unlock();
+		if (delegation)
+			__nfs_inode_return_delegation(inode, delegation);
+		iput(inode);
+		goto restart;
+	}
+	rcu_read_unlock();
+out:
+	nfs_put_client(clp);
+	module_put_and_exit(0);
+}
+
+void nfs_expire_all_delegations(struct nfs_client *clp)
+{
+	struct task_struct *task;
+
+	__module_get(THIS_MODULE);
+	atomic_inc(&clp->cl_count);
+	task = kthread_run(nfs_do_expire_all_delegations, clp,
+				"%s-delegreturn",
+				rpc_peeraddr2str(clp->cl_rpcclient,
+							RPC_DISPLAY_ADDR));
+	if (!IS_ERR(task))
+		return;
+	nfs_put_client(clp);
+	module_put(THIS_MODULE);
+}
+
+/*
+ * Return all delegations following an NFS4ERR_CB_PATH_DOWN error.
+ */
+void nfs_handle_cb_pathdown(struct nfs_client *clp)
+{
+	struct nfs_delegation *delegation;
+	struct inode *inode;
+
+	if (clp == NULL)
+		return;
+restart:
+	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);
+		rcu_read_unlock();
+		if (delegation != NULL)
+			__nfs_inode_return_delegation(inode, delegation);
+		iput(inode);
+		goto restart;
+	}
+	rcu_read_unlock();
+}
+
+struct recall_threadargs {
+	struct inode *inode;
+	struct nfs_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 nfs_client *clp = NFS_SERVER(inode)->nfs_client;
+	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 = nfs_detach_delegation_locked(nfsi, args->stateid);
+	if (delegation != NULL)
+		args->result = 0;
+	else
+		args->result = -ENOENT;
+	spin_unlock(&clp->cl_lock);
+	complete(&args->started);
+	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, 1);
+	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 nfs_client *clp, const struct nfs_fh *fhandle)
+{
+	struct nfs_delegation *delegation;
+	struct inode *res = NULL;
+	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;
+		}
+	}
+	rcu_read_unlock();
+	return res;
+}
+
+/*
+ * Mark all delegations as needing to be reclaimed
+ */
+void nfs_delegation_mark_reclaim(struct nfs_client *clp)
+{
+	struct nfs_delegation *delegation;
+	rcu_read_lock();
+	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list)
+		delegation->flags |= NFS_DELEGATION_NEED_RECLAIM;
+	rcu_read_unlock();
+}
+
+/*
+ * Reap all unclaimed delegations after reboot recovery is done
+ */
+void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
+{
+	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;
+		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)
+			nfs_free_delegation(delegation);
+		goto restart;
+	}
+	rcu_read_unlock();
+}
+
+int nfs4_copy_delegation_stateid(nfs4_stateid *dst, struct inode *inode)
+{
+	struct nfs_inode *nfsi = NFS_I(inode);
+	struct nfs_delegation *delegation;
+	int ret = 0;
+
+	rcu_read_lock();
+	delegation = rcu_dereference(nfsi->delegation);
+	if (delegation != NULL) {
+		memcpy(dst->data, delegation->stateid.data, sizeof(dst->data));
+		ret = 1;
+	}
+	rcu_read_unlock();
+	return ret;
+}