ext2: don't inherit inappropriate inode flags from parent

At present BTREE/INDEX is the only flag that new ext2 inodes do NOT
inherit from their parent.  In addition prevent the flags DIRTY, ECOMPR,
INDEX, IMAGIC and TOPDIR from being inherited.  List inheritable flags
explicitly to prevent future flags from accidentally being inherited.

This fixes the TOPDIR flag inheritance bug reported at
http://bugzilla.kernel.org/show_bug.cgi?id=9866.

Signed-off-by: Duane Griffin <duaneg@dghda.com>
Acked-by: Andreas Dilger <adilger@sun.com>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/ext2/ialloc.c

@@ -565,7 +565,7 @@ got:
 	inode->i_blocks = 0;
 	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
 	memset(ei->i_data, 0, sizeof(ei->i_data));
-	ei->i_flags = EXT2_I(dir)->i_flags & ~EXT2_BTREE_FL;
+	ei->i_flags = EXT2_I(dir)->i_flags & EXT2_FL_INHERITED;
 	if (S_ISLNK(mode))
 		ei->i_flags &= ~(EXT2_IMMUTABLE_FL|EXT2_APPEND_FL);
 	/* dirsync is only applied to directories */

include/linux/ext2_fs.h

@@ -194,6 +194,13 @@ struct ext2_group_desc
 #define EXT2_FL_USER_VISIBLE		FS_FL_USER_VISIBLE	/* User visible flags */
 #define EXT2_FL_USER_MODIFIABLE		FS_FL_USER_MODIFIABLE	/* User modifiable flags */
 
+/* Flags that should be inherited by new inodes from their parent. */
+#define EXT2_FL_INHERITED (EXT2_SECRM_FL | EXT2_UNRM_FL | EXT2_COMPR_FL |\
+			   EXT2_SYNC_FL | EXT2_IMMUTABLE_FL | EXT2_APPEND_FL |\
+			   EXT2_NODUMP_FL | EXT2_NOATIME_FL | EXT2_COMPRBLK_FL|\
+			   EXT2_NOCOMP_FL | EXT2_JOURNAL_DATA_FL |\
+			   EXT2_NOTAIL_FL | EXT2_DIRSYNC_FL)
+
 /*
  * ioctl commands
  */