[PATCH 3/6] ext4: don't inherit inappropriate inode flags from parent

["Duane Griffin" <duaneg@dghda.com>]

At present INDEX and EXTENTS are the only flags that new ext4 inodes do
NOT inherit from their parent. In addition prevent the flags DIRTY, ECOMPR,
IMAGIC, TOPDIR, HUGE_FILE and EXT_MIGRATE from being inherited. List
inheritable flags explicitly to prevent future flags from accidentally being
inherited.

Signed-off-by: Duane Griffin <duaneg@dghda.com>
--

This is v2 with inheritable flags now explicitly specified, as per Andreas'
request.

---
 fs/ext4/ext4.h   |    8 ++++++++
 fs/ext4/ialloc.c |    2 +-
 2 files changed, 9 insertions(+), 1 deletions(-)

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 8158083..1a4faa5 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -235,6 +235,14 @@ struct ext4_group_desc
 #define EXT4_FL_USER_VISIBLE		0x000BDFFF /* User visible flags */
 #define EXT4_FL_USER_MODIFIABLE		0x000380FF /* User modifiable flags */
 
+/* Flags that should be inherited by new inodes from their parent. */
+#define EXT4_FL_INHERITED (EXT4_SECRM_FL | EXT4_UNRM_FL | EXT4_COMPR_FL |\
+			   EXT4_SYNC_FL | EXT4_IMMUTABLE_FL | EXT4_APPEND_FL |\
+			   EXT4_NODUMP_FL | EXT4_NOATIME_FL |\
+			   EXT4_COMPRBLK_FL | EXT4_NOCOMPR_FL |\
+			   EXT4_JOURNAL_DATA_FL | EXT4_NOTAIL_FL|\
+			   EXT4_DIRSYNC_FL)
+
 /*
  * Inode dynamic state flags
  */
diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index c6efbab..ff25d57 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -702,7 +702,7 @@ got:
 	 * newly created directory and file only if -o extent mount option is
 	 * specified
 	 */
-	ei->i_flags = EXT4_I(dir)->i_flags & ~(EXT4_INDEX_FL|EXT4_EXTENTS_FL);
+	ei->i_flags = EXT4_I(dir)->i_flags & EXT4_FL_INHERITED;
 	if (S_ISLNK(mode))
 		ei->i_flags &= ~(EXT4_IMMUTABLE_FL|EXT4_APPEND_FL);
 	/* dirsync only applies to directories */
-- 
1.5.3.7