ext4: tighten restrictions on inode flags

At the moment there are few restrictions on which flags may be set on
which inodes.  Specifically DIRSYNC may only be set on directories and
IMMUTABLE and APPEND may not be set on links.  Tighten that to disallow
TOPDIR being set on non-directories and only NODUMP and NOATIME to be set
on non-regular file, non-directories.

Introduces a flags masking function which masks flags based on mode and
use it during inode creation and when flags are set via the ioctl to
facilitate future consistency.

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: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 1 insertions, 2 deletions

diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index 42dc83fb247a..22dd29f3ebc9 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -48,8 +48,7 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
                 if (err)
                         return err;
 
-                if (!S_ISDIR(inode->i_mode))
-                        flags &= ~EXT4_DIRSYNC_FL;
+                flags = ext4_mask_flags(inode->i_mode, flags);
 
                 err = -EPERM;
                 mutex_lock(&inode->i_mutex);