Merge tag 'nfs-for-3.4-3' of git://git.linux-nfs.org/projects/trondmy/linux-nfs

Pull NFS client bugfixes from Trond Myklebust:
 - Fix NFSv4 infinite loops on open(O_TRUNC)
 - Fix an Oops and an infinite loop in the NFSv4 flock code
 - Don't register the PipeFS filesystem until it has been set up
 - Fix an Oops in nfs_try_to_update_request
 - Don't reuse NFSv4 open owners: fixes a bad sequence id storm.

* tag 'nfs-for-3.4-3' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
  NFSv4: Keep dropped state owners on the LRU list for a while
  NFSv4: Ensure that we don't drop a state owner more than once
  NFSv4: Ensure we do not reuse open owner names
  nfs: Enclose hostname in brackets when needed in nfs_do_root_mount
  NFS: put open context on error in nfs_flush_multi
  NFS: put open context on error in nfs_pagein_multi
  NFSv4: Fix open(O_TRUNC) and ftruncate() error handling
  NFSv4: Ensure that we check lock exclusive/shared type against open modes
  NFSv4: Ensure that the LOCK code sets exception->inode
  NFS: check for req==NULL in nfs_try_to_update_request cleanup
  SUNRPC: register PipeFS file system after pernet sybsystem

1 files changed, 19 insertions, 12 deletions

diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index 0f43414eb25..7f0fcfc1fe9 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -393,6 +393,7 @@ nfs4_remove_state_owner_locked(struct nfs4_state_owner *sp)
 static void
 nfs4_init_seqid_counter(struct nfs_seqid_counter *sc)
 {
+	sc->create_time = ktime_get();
 	sc->flags = 0;
 	sc->counter = 0;
 	spin_lock_init(&sc->lock);
@@ -434,13 +435,17 @@ nfs4_alloc_state_owner(struct nfs_server *server,
 static void
 nfs4_drop_state_owner(struct nfs4_state_owner *sp)
 {
-	if (!RB_EMPTY_NODE(&sp->so_server_node)) {
+	struct rb_node *rb_node = &sp->so_server_node;
+
+	if (!RB_EMPTY_NODE(rb_node)) {
 		struct nfs_server *server = sp->so_server;
 		struct nfs_client *clp = server->nfs_client;
 
 		spin_lock(&clp->cl_lock);
-		rb_erase(&sp->so_server_node, &server->state_owners);
-		RB_CLEAR_NODE(&sp->so_server_node);
+		if (!RB_EMPTY_NODE(rb_node)) {
+			rb_erase(rb_node, &server->state_owners);
+			RB_CLEAR_NODE(rb_node);
+		}
 		spin_unlock(&clp->cl_lock);
 	}
 }
@@ -516,6 +521,14 @@ out:
 /**
  * nfs4_put_state_owner - Release a nfs4_state_owner
  * @sp: state owner data to release
+ *
+ * Note that we keep released state owners on an LRU
+ * list.
+ * This caches valid state owners so that they can be
+ * reused, to avoid the OPEN_CONFIRM on minor version 0.
+ * It also pins the uniquifier of dropped state owners for
+ * a while, to ensure that those state owner names are
+ * never reused.
  */
 void nfs4_put_state_owner(struct nfs4_state_owner *sp)
 {
@@ -525,15 +538,9 @@ void nfs4_put_state_owner(struct nfs4_state_owner *sp)
 	if (!atomic_dec_and_lock(&sp->so_count, &clp->cl_lock))
 		return;
 
-	if (!RB_EMPTY_NODE(&sp->so_server_node)) {
-		sp->so_expires = jiffies;
-		list_add_tail(&sp->so_lru, &server->state_owners_lru);
-		spin_unlock(&clp->cl_lock);
-	} else {
-		nfs4_remove_state_owner_locked(sp);
-		spin_unlock(&clp->cl_lock);
-		nfs4_free_state_owner(sp);
-	}
+	sp->so_expires = jiffies;
+	list_add_tail(&sp->so_lru, &server->state_owners_lru);
+	spin_unlock(&clp->cl_lock);
 }
 
 /**