Re: [ 64/82] ext4: dont trash state flags in EXT4_IOC_SETFLAGS

From: Ben Hutchings
Date: Thu Jun 07 2012 - 23:03:15 EST


On Thu, 2012-06-07 at 13:04 +0900, Greg KH wrote:
> 3.4-stable review patch. If anyone has any objections, please let me know.
>
> ------------------
>
> From: Theodore Ts'o <tytso@xxxxxxx>
>
> commit 79906964a187c405db72a3abc60eb9b50d804fbc upstream.
>
> In commit 353eb83c we removed i_state_flags with 64-bit longs, But
> when handling the EXT4_IOC_SETFLAGS ioctl, we replace i_flags
> directly, which trashes the state flags which are stored in the high
> 32-bits of i_flags on 64-bit platforms. So use the the
> ext4_{set,clear}_inode_flags() functions which use atomic bit
> manipulation functions instead.
[...]
> @@ -115,8 +115,14 @@ long ext4_ioctl(struct file *filp, unsig
> if (err)
> goto flags_err;
>
> - flags = flags & EXT4_FL_USER_MODIFIABLE;
> - flags |= oldflags & ~EXT4_FL_USER_MODIFIABLE;
> + for (i = 0, mask = 1; i < 32; i++, mask <<= 1) {
> + if (!(mask & EXT4_FL_USER_MODIFIABLE))
> + continue;
> + if (mask & flags)
> + ext4_set_inode_flag(inode, i);
> + else
> + ext4_clear_inode_flag(inode, i);
> + }
> ei->i_flags = flags;
[...]

Shouldn't this last assignment have been deleted?

Ben.

--
Ben Hutchings
I haven't lost my mind; it's backed up on tape somewhere.

Attachment: signature.asc
Description: This is a digitally signed message part