CRED: Use creds in file structs

Attach creds to file structs and discard f_uid/f_gid.

file_operations::open() methods (such as hppfs_open()) should use file->f_cred
rather than current_cred().  At the moment file->f_cred will be current_cred()
at this point.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
diff --git a/fs/coda/file.c b/fs/coda/file.c
index 29137ff..5a87699 100644
--- a/fs/coda/file.c
+++ b/fs/coda/file.c
@@ -174,7 +174,7 @@
 	BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
 
 	err = venus_close(coda_inode->i_sb, coda_i2f(coda_inode),
-			  coda_flags, coda_file->f_uid);
+			  coda_flags, coda_file->f_cred->fsuid);
 
 	host_inode = cfi->cfi_container->f_path.dentry->d_inode;
 	cii = ITOC(coda_inode);
diff --git a/fs/file_table.c b/fs/file_table.c
index bc4563f..0fbcacc 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -36,7 +36,9 @@
 
 static inline void file_free_rcu(struct rcu_head *head)
 {
-	struct file *f =  container_of(head, struct file, f_u.fu_rcuhead);
+	struct file *f = container_of(head, struct file, f_u.fu_rcuhead);
+
+	put_cred(f->f_cred);
 	kmem_cache_free(filp_cachep, f);
 }
 
@@ -121,8 +123,7 @@
 	INIT_LIST_HEAD(&f->f_u.fu_list);
 	atomic_long_set(&f->f_count, 1);
 	rwlock_init(&f->f_owner.lock);
-	f->f_uid = cred->fsuid;
-	f->f_gid = cred->fsgid;
+	f->f_cred = get_cred(cred);
 	eventpoll_init_file(f);
 	/* f->f_version: 0 */
 	return f;
diff --git a/fs/hppfs/hppfs.c b/fs/hppfs/hppfs.c
index 795e2c1..b278f7f 100644
--- a/fs/hppfs/hppfs.c
+++ b/fs/hppfs/hppfs.c
@@ -426,7 +426,7 @@
 
 static int hppfs_open(struct inode *inode, struct file *file)
 {
-	const struct cred *cred = current_cred();
+	const struct cred *cred = file->f_cred;
 	struct hppfs_private *data;
 	struct vfsmount *proc_mnt;
 	struct dentry *proc_dentry;
@@ -490,7 +490,7 @@
 
 static int hppfs_dir_open(struct inode *inode, struct file *file)
 {
-	const struct cred *cred = current_cred();
+	const struct cred *cred = file->f_cred;
 	struct hppfs_private *data;
 	struct vfsmount *proc_mnt;
 	struct dentry *proc_dentry;