On Tue, Sep 30, 2014 at 11:46:05AM +1000, Dave Chinner wrote:
> From: Dave Chinner <dchinner@xxxxxxxxxx>
>
> Currently the extent size hint is set unconditionally in
> xfs_ioctl_setattr(), even when the FSX_EXTSIZE flag is not set. This
> means we can set values from uninitialised stack variables. Hence
> only set the extent size hint from userspace when both the mask
> falg is set and the inode has the XFS_DIFLAG_EXTSIZE flag set to
> indicate that we should have an extent size hint set on the inode.
>
> Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>
> ---
> fs/xfs/xfs_ioctl.c | 16 ++++++++++++++--
> 1 file changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
> index 87c3bd1..24c926b 100644
> --- a/fs/xfs/xfs_ioctl.c
> +++ b/fs/xfs/xfs_ioctl.c
> @@ -1231,13 +1231,25 @@ xfs_ioctl_setattr(
>
> }
>
> - if (mask & FSX_EXTSIZE)
> - ip->i_d.di_extsize = fa->fsx_extsize >> mp->m_sb.sb_blocklog;
> if (mask & FSX_XFLAGS) {
> xfs_set_diflags(ip, fa->fsx_xflags);
> xfs_diflags_to_linux(ip);
> }
>
> + /*
> + * Only set the extent size hint if we've already determined that the
> + * extent size hint should be set on the inode. If no extent size flags
> + * are set on the inode then unconditionally clear the extent size hint.
> + */
> + if (mask & FSX_EXTSIZE) {
> + int extsize = 0;
> +
> + if (ip->i_d.di_flags &
> + (XFS_DIFLAG_EXTSIZE | XFS_DIFLAG_EXTSZINHERIT))
> + extsize = fa->fsx_extsize >> mp->m_sb.sb_blocklog;
> + ip->i_d.di_extsize = extsize;
Quick question: this sounds sane, but it will have the following effect
(if I understand things correctly): updating other flags on the inode
(e.g. XFS_XFLAG_NOATIME) might change the recorded extent size. True, it
will correct the size if not appropriate and it will have a noop impact,
but still it will be an unrelated inode change. Would it make sense to
document this in the xfsctl man page then?
thanks,
iustin
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