[PATCH AUTOSEL 5.10 12/37] NFSv4: Fix delegation return in cases where we have to retry

[PATCH AUTOSEL 5.10 12/37] NFSv4: Fix delegation return in cases where we have to retry

[Sasha Levin]

From: Trond Myklebust <trond.myklebust@hammerspace.com>

[ Upstream commit be20037725d17935ec669044bd2b15bc40c3b5ab ]

If we're unable to immediately recover all locks because the server is
unable to immediately service our reclaim calls, then we want to retry
after we've finished servicing all the other asynchronous delegation
returns on our queue.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/nfs/delegation.c | 71 +++++++++++++++++++++++++++++++++++----------
 fs/nfs/delegation.h |  1 +
 fs/nfs/nfs4_fs.h    |  1 +
 3 files changed, 58 insertions(+), 15 deletions(-)

diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c
index 04bf8066980c..d6ac2c4f88b6 100644
--- a/fs/nfs/delegation.c
+++ b/fs/nfs/delegation.c
@@ -75,6 +75,13 @@ void nfs_mark_delegation_referenced(struct nfs_delegation *delegation)
 	set_bit(NFS_DELEGATION_REFERENCED, &delegation->flags);
 }
 
+static void nfs_mark_return_delegation(struct nfs_server *server,
+				       struct nfs_delegation *delegation)
+{
+	set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
+	set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
+}
+
 static bool
 nfs4_is_valid_delegation(const struct nfs_delegation *delegation,
 		fmode_t flags)
@@ -293,6 +300,7 @@ nfs_start_delegation_return_locked(struct nfs_inode *nfsi)
 		goto out;
 	spin_lock(&delegation->lock);
 	if (!test_and_set_bit(NFS_DELEGATION_RETURNING, &delegation->flags)) {
+		clear_bit(NFS_DELEGATION_RETURN_DELAYED, &delegation->flags);
 		/* Refcount matched in nfs_end_delegation_return() */
 		ret = nfs_get_delegation(delegation);
 	}
@@ -314,16 +322,17 @@ nfs_start_delegation_return(struct nfs_inode *nfsi)
 	return delegation;
 }
 
-static void
-nfs_abort_delegation_return(struct nfs_delegation *delegation,
-		struct nfs_client *clp)
+static void nfs_abort_delegation_return(struct nfs_delegation *delegation,
+					struct nfs_client *clp, int err)
 {
 
 	spin_lock(&delegation->lock);
 	clear_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
-	set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
+	if (err == -EAGAIN) {
+		set_bit(NFS_DELEGATION_RETURN_DELAYED, &delegation->flags);
+		set_bit(NFS4CLNT_DELEGRETURN_DELAYED, &clp->cl_state);
+	}
 	spin_unlock(&delegation->lock);
-	set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
 }
 
 static struct nfs_delegation *
@@ -528,7 +537,7 @@ static int nfs_end_delegation_return(struct inode *inode, struct nfs_delegation
 	} while (err == 0);
 
 	if (err) {
-		nfs_abort_delegation_return(delegation, clp);
+		nfs_abort_delegation_return(delegation, clp, err);
 		goto out;
 	}
 
@@ -557,6 +566,7 @@ static bool nfs_delegation_need_return(struct nfs_delegation *delegation)
 	if (ret)
 		clear_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);
 	if (test_bit(NFS_DELEGATION_RETURNING, &delegation->flags) ||
+	    test_bit(NFS_DELEGATION_RETURN_DELAYED, &delegation->flags) ||
 	    test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
 		ret = false;
 
@@ -636,6 +646,38 @@ static int nfs_server_return_marked_delegations(struct nfs_server *server,
 	return err;
 }
 
+static bool nfs_server_clear_delayed_delegations(struct nfs_server *server)
+{
+	struct nfs_delegation *d;
+	bool ret = false;
+
+	list_for_each_entry_rcu (d, &server->delegations, super_list) {
+		if (!test_bit(NFS_DELEGATION_RETURN_DELAYED, &d->flags))
+			continue;
+		nfs_mark_return_delegation(server, d);
+		clear_bit(NFS_DELEGATION_RETURN_DELAYED, &d->flags);
+		ret = true;
+	}
+	return ret;
+}
+
+static bool nfs_client_clear_delayed_delegations(struct nfs_client *clp)
+{
+	struct nfs_server *server;
+	bool ret = false;
+
+	if (!test_and_clear_bit(NFS4CLNT_DELEGRETURN_DELAYED, &clp->cl_state))
+		goto out;
+	rcu_read_lock();
+	list_for_each_entry_rcu (server, &clp->cl_superblocks, client_link) {
+		if (nfs_server_clear_delayed_delegations(server))
+			ret = true;
+	}
+	rcu_read_unlock();
+out:
+	return ret;
+}
+
 /**
  * nfs_client_return_marked_delegations - return previously marked delegations
  * @clp: nfs_client to process
@@ -648,8 +690,14 @@ static int nfs_server_return_marked_delegations(struct nfs_server *server,
  */
 int nfs_client_return_marked_delegations(struct nfs_client *clp)
 {
-	return nfs_client_for_each_server(clp,
-			nfs_server_return_marked_delegations, NULL);
+	int err = nfs_client_for_each_server(
+		clp, nfs_server_return_marked_delegations, NULL);
+	if (err)
+		return err;
+	/* If a return was delayed, sleep to prevent hard looping */
+	if (nfs_client_clear_delayed_delegations(clp))
+		ssleep(1);
+	return 0;
 }
 
 /**
@@ -764,13 +812,6 @@ static void nfs_mark_return_if_closed_delegation(struct nfs_server *server,
 	set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
 }
 
-static void nfs_mark_return_delegation(struct nfs_server *server,
-		struct nfs_delegation *delegation)
-{
-	set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
-	set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
-}
-
 static bool nfs_server_mark_return_all_delegations(struct nfs_server *server)
 {
 	struct nfs_delegation *delegation;
diff --git a/fs/nfs/delegation.h b/fs/nfs/delegation.h
index 9b00a0b7f832..26f57a99da84 100644
--- a/fs/nfs/delegation.h
+++ b/fs/nfs/delegation.h
@@ -36,6 +36,7 @@ enum {
 	NFS_DELEGATION_REVOKED,
 	NFS_DELEGATION_TEST_EXPIRED,
 	NFS_DELEGATION_INODE_FREEING,
+	NFS_DELEGATION_RETURN_DELAYED,
 };
 
 int nfs_inode_set_delegation(struct inode *inode, const struct cred *cred,
diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
index 543d916f79ab..3e344bec3647 100644
--- a/fs/nfs/nfs4_fs.h
+++ b/fs/nfs/nfs4_fs.h
@@ -45,6 +45,7 @@ enum nfs4_client_state {
 	NFS4CLNT_RECALL_RUNNING,
 	NFS4CLNT_RECALL_ANY_LAYOUT_READ,
 	NFS4CLNT_RECALL_ANY_LAYOUT_RW,
+	NFS4CLNT_DELEGRETURN_DELAYED,
 };
 
 #define NFS4_RENEW_TIMEOUT		0x01
-- 
2.30.2

[PATCH AUTOSEL 5.10 25/37] NFS: nfs_find_open_context() may only select open files

[Sasha Levin]

From: Trond Myklebust <trond.myklebust@hammerspace.com>

[ Upstream commit e97bc66377bca097e1f3349ca18ca17f202ff659 ]

If a file has already been closed, then it should not be selected to
support further I/O.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
[Trond: Fix an invalid pointer deref reported by Colin Ian King]
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/nfs/inode.c         | 4 ++++
 include/linux/nfs_fs.h | 1 +
 2 files changed, 5 insertions(+)

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index dc2cbca98fb0..9811880470a0 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -1064,6 +1064,7 @@ EXPORT_SYMBOL_GPL(nfs_inode_attach_open_context);
 void nfs_file_set_open_context(struct file *filp, struct nfs_open_context *ctx)
 {
 	filp->private_data = get_nfs_open_context(ctx);
+	set_bit(NFS_CONTEXT_FILE_OPEN, &ctx->flags);
 	if (list_empty(&ctx->list))
 		nfs_inode_attach_open_context(ctx);
 }
@@ -1083,6 +1084,8 @@ struct nfs_open_context *nfs_find_open_context(struct inode *inode, const struct
 			continue;
 		if ((pos->mode & (FMODE_READ|FMODE_WRITE)) != mode)
 			continue;
+		if (!test_bit(NFS_CONTEXT_FILE_OPEN, &pos->flags))
+			continue;
 		ctx = get_nfs_open_context(pos);
 		if (ctx)
 			break;
@@ -1098,6 +1101,7 @@ void nfs_file_clear_open_context(struct file *filp)
 	if (ctx) {
 		struct inode *inode = d_inode(ctx->dentry);
 
+		clear_bit(NFS_CONTEXT_FILE_OPEN, &ctx->flags);
 		/*
 		 * We fatal error on write before. Try to writeback
 		 * every page again.
diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index a2c6455ea3fa..91a6525a98cb 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -79,6 +79,7 @@ struct nfs_open_context {
 #define NFS_CONTEXT_RESEND_WRITES	(1)
 #define NFS_CONTEXT_BAD			(2)
 #define NFS_CONTEXT_UNLOCK	(3)
+#define NFS_CONTEXT_FILE_OPEN		(4)
 	int error;
 
 	struct list_head list;
-- 
2.30.2