JFS: add uid, gid, and umask mount options

OS/2 doesn't initialize the uid, gid, or unix-style permission bits.  The
uid, gid, & umask mount options perform pretty much like those for the fat
file system, overriding what is stored on disk.  This is useful for users
sharing the file system with OS/2.

I implemented a little feature so that if you mask the execute bit, it
will be re-enabled on directories when the appropriate read bit is unmasked.
I didn't want to implement an fmask & dmask option.

Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com>
diff --git a/fs/jfs/jfs_inode.c b/fs/jfs/jfs_inode.c
index ffd2a8a..495df40 100644
--- a/fs/jfs/jfs_inode.c
+++ b/fs/jfs/jfs_inode.c
@@ -83,6 +83,13 @@
 		inode->i_gid = current->fsgid;
 
 	/*
+	 * New inodes need to save sane values on disk when
+	 * uid & gid mount options are used
+	 */
+	jfs_inode->saved_uid = inode->i_uid;
+	jfs_inode->saved_gid = inode->i_gid;
+
+	/*
 	 * Allocate inode to quota.
 	 */
 	if (DQUOT_ALLOC_INODE(inode)) {