CRED: Wrap task credential accesses in the HPFS filesystem

Wrap access to task credentials so that they can be separated more easily from
the task_struct during the introduction of COW creds.

Change most current->(|e|s|fs)[ug]id to current_(|e|s|fs)[ug]id().

Change some task->e?[ug]id to task_e?[ug]id().  In some places it makes more
sense to use RCU directly rather than a convenient wrapper; these will be
addressed by later patches.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz>
Signed-off-by: James Morris <jmorris@namei.org>

fs/hpfs/namei.c

@@ -92,11 +92,11 @@ static int hpfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 	inc_nlink(dir);
 	insert_inode_hash(result);
 
-	if (result->i_uid != current->fsuid ||
-	    result->i_gid != current->fsgid ||
+	if (result->i_uid != current_fsuid() ||
+	    result->i_gid != current_fsgid() ||
 	    result->i_mode != (mode | S_IFDIR)) {
-		result->i_uid = current->fsuid;
-		result->i_gid = current->fsgid;
+		result->i_uid = current_fsuid();
+		result->i_gid = current_fsgid();
 		result->i_mode = mode | S_IFDIR;
 		hpfs_write_inode_nolock(result);
 	}
@@ -184,11 +184,11 @@ static int hpfs_create(struct inode *dir, struct dentry *dentry, int mode, struc
 
 	insert_inode_hash(result);
 
-	if (result->i_uid != current->fsuid ||
-	    result->i_gid != current->fsgid ||
+	if (result->i_uid != current_fsuid() ||
+	    result->i_gid != current_fsgid() ||
 	    result->i_mode != (mode | S_IFREG)) {
-		result->i_uid = current->fsuid;
-		result->i_gid = current->fsgid;
+		result->i_uid = current_fsuid();
+		result->i_gid = current_fsgid();
 		result->i_mode = mode | S_IFREG;
 		hpfs_write_inode_nolock(result);
 	}
@@ -247,8 +247,8 @@ static int hpfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t
 	result->i_mtime.tv_nsec = 0;
 	result->i_atime.tv_nsec = 0;
 	hpfs_i(result)->i_ea_size = 0;
-	result->i_uid = current->fsuid;
-	result->i_gid = current->fsgid;
+	result->i_uid = current_fsuid();
+	result->i_gid = current_fsgid();
 	result->i_nlink = 1;
 	result->i_size = 0;
 	result->i_blocks = 1;
@@ -325,8 +325,8 @@ static int hpfs_symlink(struct inode *dir, struct dentry *dentry, const char *sy
 	result->i_atime.tv_nsec = 0;
 	hpfs_i(result)->i_ea_size = 0;
 	result->i_mode = S_IFLNK | 0777;
-	result->i_uid = current->fsuid;
-	result->i_gid = current->fsgid;
+	result->i_uid = current_fsuid();
+	result->i_gid = current_fsgid();
 	result->i_blocks = 1;
 	result->i_nlink = 1;
 	result->i_size = strlen(symlink);

fs/hpfs/super.c

@@ -475,8 +475,8 @@ static int hpfs_fill_super(struct super_block *s, void *options, int silent)
 
 	init_MUTEX(&sbi->hpfs_creation_de);
 
-	uid = current->uid;
-	gid = current->gid;
+	uid = current_uid();
+	gid = current_gid();
 	umask = current->fs->umask;
 	lowercase = 0;
 	conv = CONV_BINARY;