NFS: Prevent memory allocation failure in nfsacl_encode()

nfsacl_encode() allocates memory in certain cases.  This of course
is not guaranteed to work.

Since commit 9f06c719 "SUNRPC: New xdr_streams XDR encoder API", the
kernel's XDR encoders can't return a result indicating possibly a
failure, so a memory allocation failure in nfsacl_encode() has become
fatal (ie, the XDR code Oopses) in some cases.

However, the allocated memory is a tiny fixed amount, on the order
of 40-50 bytes.  We can easily use a stack-allocated buffer for
this, with only a wee bit of nose-holding.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/posix_acl.h b/include/linux/posix_acl.h
index d68283a898bb..54211c1cd926 100644
--- a/include/linux/posix_acl.h
+++ b/include/linux/posix_acl.h
@@ -71,6 +71,7 @@ posix_acl_release(struct posix_acl *acl)
 
 /* posix_acl.c */
 
+extern void posix_acl_init(struct posix_acl *, int);
 extern struct posix_acl *posix_acl_alloc(int, gfp_t);
 extern struct posix_acl *posix_acl_clone(const struct posix_acl *, gfp_t);
 extern int posix_acl_valid(const struct posix_acl *);