NFS: Remove BKL usage from open()

All the NFSv4 stateful operations are already protected by other locks (in
particular by the rpc_sequence locks.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/dir.c

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 73e0f97..c68ec44 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -139,10 +139,8 @@
 
 	nfs_inc_stats(inode, NFSIOS_VFSOPEN);
 
-	lock_kernel();
 	/* Call generic open code in order to cache credentials */
 	res = nfs_open(inode, filp);
-	unlock_kernel();
 	return res;
 }
 
@@ -1019,9 +1017,7 @@
 	}
 
 	/* Open the file on the server */
-	lock_kernel();
 	res = nfs4_atomic_open(dir, dentry, nd);
-	unlock_kernel();
 	if (IS_ERR(res)) {
 		error = PTR_ERR(res);
 		switch (error) {
@@ -1083,9 +1079,7 @@
 	 * operations that change the directory. We therefore save the
 	 * change attribute *before* we do the RPC call.
 	 */
-	lock_kernel();
 	ret = nfs4_open_revalidate(dir, dentry, openflags, nd);
-	unlock_kernel();
 out:
 	dput(parent);
 	if (!ret)

fs/nfs/file.c

diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index f919d9a..9f1bed9 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -128,9 +128,7 @@
 		return res;
 
 	nfs_inc_stats(inode, NFSIOS_VFSOPEN);
-	lock_kernel();
 	res = nfs_open(inode, filp);
-	unlock_kernel();
 	return res;
 }
 

fs/nfs/nfs4proc.c

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 4451287..c910413 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -451,9 +451,7 @@
 		/* Save the delegation */
 		memcpy(stateid.data, delegation->stateid.data, sizeof(stateid.data));
 		rcu_read_unlock();
-		lock_kernel();
 		ret = nfs_may_open(state->inode, state->owner->so_cred, open_mode);
-		unlock_kernel();
 		if (ret != 0)
 			goto out;
 		ret = -EAGAIN;